LETTER TO DENNIS PAGEN

Dear Dennis Pagen,

     This is the second letter sent to you.  You might remember receiving the first letter in the early nineteen eighties.  If you do not recall the previous letter, here is a hint.  The first letter requested that you recommend some books on the subject of avian aerodynamics.  Your reply was generous and provided useful information.  Your help is sincerely appreciated Dennis.  Thank you!

     At this time, you are the only person who has contributed to a project that pertains to a new method for controlling the flight of a hang glider.  There is a sporadic and so far, unsuccessful effort underway to wright a thesis that will explains how this concept works.  The plan is to publish the entire document on the internet when completed.  It is believed that lives can be saved by making this nascent technology open-sourced.

     When writing a technical paper, it is useful to imagine talking to a targeted audience.  When the subject matter is esoteric, it is easiest to select someone that is recognized as an expert in the related field of study.  Most of what is known about hang gliding aerodynamics and hang glider design can be found in your instruction manuals and many magazine articles.  Therefore, you were the one who was chosen.

     The following are some excerpts taken from the attempted thesis.  This innovation cannot be fully explained by these brief extracts.  Even so, you can get some insight as to what the concept is about by reading them.  It is hoped that you will keep an open mind-set while imagining what it would be like to fly a hang glider like the one about to be revealed to you.  The intention of this letter is to arouse enough curiosity that you might become interested in becoming a valued partner in the ACE project.

=================================================================================

The ACE Concept

Introduction

     This discussion endeavors to present a novel method for controlling the flight of a hang glider.  This concept is given the acronym, ACE.  ACE may stand for articulated control enhancement or avian control enhancement.  The ACE method of flight control is as much of a discovery as it is an invention.  An improved understanding of how soaring birds perform their rudimentary gliding flight, eventually lead to its conception.

     ACE uses biomimicry to emulate the manner in which avian lifeforms control their non-flapping flight.  ACE is a synthesis of two diverse methods utilized to control flight.  Weight shift is integrated with avian-style interactive aerodynamic flight control.  These two dissimilar methods are united in a way that causes them to work together in congruence as a single synergistic system.

     A hang glider that would embody ACE technology is signified herein by the name, Ascender.  The Ascender is the archetype for another category of hang glider.  Instead of being called a flexible or rigid winged hang glider, it should be referred to as an articulated winged hang glider.  The Ascender gives rise to a realistic bird-like style of humanoid flight.  Some of the capabilities exhibited by soaring birds can be made available to people through the implementation of an Ascender type of hang glider based on the ACE method of flight control.

     The Ascender is simple to set up and break down.  It is easy to load and unload for transport.  It is launched and landed by foot.  The pilot flies in the face down or prone position.  She performs the same weight shifting maneuvers as those used to control a conventional weight shift hang glider.  Nevertheless, when flying the Ascender, those same pilot actions have a potentiated effect.

     Every activity of the flight process, including the takeoff run and the landing flair can be improved through the actualization of a properly engineered Ascender.  No empirical evidence will be presented at this time.  However, it is intended that the feasibility of the ACE concept be established by the rational logic of the principles upon which it is founded.  This discussion strives to explain the ACE method of flight control and some of its potential benefits for the reader’s pragmatic consideration.

Triadic Wing

     The Ascender has a unique wing.  The one wing is segmented into three main parts.  Each part or wing segment is joined to the other two as an interconnected triad or unified set of three.  The wing segments fly together as a single jointed or articular wing creating a mostly confluent airflow.

     The wing segments are named according to their respective locations.  They are the left wing, right wing, and tail wing.  The complete assemblage of wing segments along with the mainframe assembly that hold them together is given the name, triadic wing.

     When referring to the left wing and right wing segments as a pair, they are called, primary wings.  The primary wings provide the primary source of lift and roll control.  The primary wings are double surface high aspect ratio airfoils.  They do not require deep cambered high-lift airfoils like those on smaller conventional hang gliders.  They are cambered to maximize laminar flow and the glide ratio while flying at the glider’s best glide speed.  The primary wings are rigid airfoils aligned as a nearly collinear couple.  A little dihedral is used to provide some roll stability.

     The leading edge of the tail wing is connected near to the trailing edges of the primary wings.  Flexible materials are used as fairing to provide a smooth shape changing transition between the primary wings themselves and between the primary wings and the tail wing.  The tail wing provides a secondary source of lift when flying at airspeeds slower than the best glide speed but faster than the stooping-flight speed.  The size and shape of the tail wing is designed to enhance the slower airspeed performance of the primary wings.  The tail wing is an active partially slotted plain flap that also functions as a multipurpose control devise.  The tail wing provides gravity actuated pitch stability, yaw control, and dive recovery.

     The three wing segments of the triadic wing are linked together with swivel joints that allow mechanical flexibility or articulated motion to take place between them.  Because the triadic wing is made of jointed segments that can be manipulated in relation to one another, the Ascender is understood to be an articulated winged hang glider.

     A linkage system is used to integrate weight shift with avian-style interactive aerodynamic flight control.  The Ascender is mechanized by the linkage system.  The glider’s triadic wing is a subassembly of the greater linkage system.  Hence, the wing segments of the triadic wing are integral links of the linkage system.  The linkage system is adjustable and governs how the actions of the pilot manipulate the wing segments.  The coalescence of weight shift with articulated aerodynamic control culminates as an amplification of direct three-axis flight controls.

Note:  Nylon bushing inserts are used as both linear and rotary bearings.  They reduce friction and prevent wear where one section of rigid tubing slides telescopically and or turns in relation to another.  They make mechanization of the Ascender possible.  The term stooping-flight is defined under the titles, “Control Surface Manipulations” and “Landing Approach.”

Triad-of-Lift

     Tripods are often used for the stable support of expensive and fragile instruments such as telescopes, cameras, transits, and etcetera.  The minimum number of legs that can guarantee balanced freestanding support is three.  This explains why most portable stands have three legs.  Tripods derive their equilibrium by establishing a counterpoised configuration.  Each leg is positioned and adjusted in a manner that counterbalances the other two.

     Within the context of non-powered flight, flight support may simply be referred to as lift.  The triadic wing is engineered to produce ongoing flight support in the form of counterpoised lift.  Hence, it could be said that the triadic wing provides stability with a metaphorical tripod-of-lift.  To eliminate the metaphor, the triadic wing is described as creating a stable triad-of-lift.

Avian Analogy

     Avian lifeforms have three major lift producing appendages.  These airfoil surfaces are their left wing, right wing, and tail wing.  During non-flapping flight, the wings of birds fly together creating a mostly confluent airflow.  They produce a potentially stable triad-of-lift.  Their ensemble of wings interacts with each other as though they were a single but segmented and articulated wing.

     The one segmented and articulated triadic wing is analogous to the three wings of avian lifeforms.  Their relative positions are the same as the wings of soaring birds.  How the wing segments interact with one another is somewhat similar to how the birds use their wings to control their gliding flight.  These conspicuous resemblances are not a coincidence.  The Ascender’s aerodynamics and the ACE method of flight control are based in large part on their example.

Note:  The wing segments of the triadic wing do not have the same strict shape as the wings of soaring birds.  This is because the sizes and the Reynolds numbers are proportionally different.  The wings of avian life forms have evolved with an emphasis on reducing viscus drag while the wings of a hang glider must be designed with more concern for the reduction of inertial drag.  Even so, the fundamental slow speed fluid mechanics is the same.

     The three largest lift producing appendages of avian lifeforms also function as control devices.  During gliding flight, birds direct their flight path with wing shape changes and relative motion between their wings.  Thus, the rudimentary flight controls of soaring birds occur in response to the dynamic exchange of forces taking place between their three synergetic wings and the surrounding or ambient atmosphere.  This is a three-way interactive form of aerodynamic controls.  The use of three-way interaction provides versatility.  Birds do not require control devices such as those used by sailplanes.  No ailerons, elevator, flaps, and etcetera are needed because birds exploit relative motion between their wings instead.  Simply stated, their wings are their control devices.

     Millions of years ago, avian lifeforms adapted to flight by evolving three mobile lift producing appendages to perform three-axis flight control within the three-dimensions of the atmosphere.  Birds have been soaring aloft ever since.  There are thousands of avian species in existence today.  They can be found almost everywhere on the planet.  This exceedingly successful three-wing planform is a classic example of convergent evolution.  It has been perfected by an exacting process known as natural selection or survival of the fittest.

     The three wings of soaring birds create a potentially stable triad-of-lift.  Avian lifeforms practice efficient flying and acute flight control with this simple arrangement.  The source from which birds apply flight control is naturally stable.  However, it is well known that birds practice unstable flight.  The instability is caused by how birds prefer to control their flight, not the ever shapeshifting configuration from which they control their flight.

     When on the ground, the bigger birds have the advantage.  However, when airborne the pecking order is inverted.  Smaller birds can often be seen chasing larger birds out of a contested airspace.  This is because the smaller birds can typically perform the most nimble flight maneuvers.  When birds compete over territorial rights, flight agility is of more consequence than size.  Hence, aerial superiority is determined chiefly by quickness in control response, not size.

     For the reason just explained and others omitted for the sake of brevity, birds intentionally sacrifice stability in exchange for quickness in control response.  Applying flight controls in a destabilizing manner is acceptable for avian lifeforms because they have lightning-fast reflexes.  Birds execute numerous manipulations of their wings to continuously balance their triad-of-lift and direct their flight path.  Most of the smaller movements happen so fast they are difficult to see.  The speed and frequency with which birds apply flight control permits constant balancing to work for them.  There super-fast reflexes compensate for the intentional sacrifice in stability.

     Like soaring birds performing rudimentary gliding flight, the Ascender’s aerodynamic flight controls occurs in response to relative movements taking place between its three wing segments.  However, the pilot is not required to have reflexes as prompt as the birds.  One reasons for this is that the pilot plus glider center of gravity is located well below the three sources of lift created by the triadic wing.  This setup supplies some manifest pendulous stability.

     When wings create lift in an essentially straight line they are said to have a planked wingedplanform.  Yet another reason why the pilot is not required to have superfast reflexes is due to how the Ascender’s primary wings are arranged.  Because the primary wings of the triadic wing are planked wings, they have some innate pitch stability.  They have a tendency to wind-vane or merge into alignment with air current directional changes as they are encountered.  The Ascender is effected less by turbulence because its primary wings tend to go with the flow or merge with the changes in air current direction instead of opposing them.  This is explained under the titles, “Planked Winged Planform” and “Articulated Versus Fixed.”

     Soaring birds do very little weight shifting while gliding.  For birds to apply aerodynamic controls, they must push against the air.  Newtonian physics asserts that the force that actually alters a bird’s flight trajectory is the reactionary force of the air pushing back against the bird.  To affect pitch control, birds push against the air with their tail wing to acquire the required reactionary forces.  How birds use their tail wings to assist with the pitching action of their primary wings and bodies is one of the main reasons for the sacrifice in stability.

     The predominant reason why lightning-fast reflexes are not required to fly the Ascender has to do with how its primary wings and tail wing interact with each other.  Because the ACE method of flight control employs weight shift in addition to aerodynamic control, the Ascender’s tail wing may be used in a somewhat different way than how the birds choose to use their tail wing.  The Ascender’s tail wing pitches in the opposite direction from that of the birds as that motion relates to the pitching actions of its primary wings.

     To help raise the angle of attack of their primary wings and bodies, birds flick the trailing edge of their tail wing up.  To help lower the angle of attack of their primary wings and bodies, birds flick the trailing edge of their tail wing down.  Using their tail wing in this manner hastens pitch control response but sacrifices pitch stability.

     The Ascender pitches the trailing edge of its tail wing down as its primary wings raise their angle of attack.  The Ascender pitches the trailing edge of its tail wing up as its primary wings lowers their angle of attack.  The Ascender acquires pitch stability by reversing how birds sacrifice their pitch stability.  This is explained under the titles, “Pitch Stability” and “The Kite-Flyer.”

Pitch Stability

     For a given set of factors, the airspeed of a hang glider is determined by its angle of attack.  Trim speed is the airspeed at which a glider flies when its angle of attack is not being influenced by the pilot and or effected by turbulence.  While cruising at trim speed, the center of lift is in vertical alignment with the center of gravity and the glider flies in a state of equilibrium.  A glider is said to be pitch stable when it has a propensity to return to its trim speed angel of attack naturally.

     Another attribute of the ACE method of flight control is called sequential transposition.  This reversal in the succession of the center of lift with the center of gravity occurs when the glider’s airspeed crosses over from one side of its trim speed angle of attack to that of the other.  This sequential transposition occurs automatically regardless of what causes the change in angle of attack to take place.

     Instead of the customary hang loop, the pilot flies suspended from the bottom end of a small subassembly.  This mechanism is another integral link of the linkage system.  Because it functions as the glider’s control lever arm, it is given the name, control stick.  The upper end of the control stick is connected to the glider’s keel tube with a hinged joint.  This allows the control stick to swing fore and aft or longitudinally in relation to the keel tube and glider.  The keel tube is mounted in nylon bushings up inside the triadic wing.  This permits the keel tube to rotate when the pilot swings sideways or laterally in relation to the glider.

     The main support straps of the pilot’s harness are wrapped around and belted through a spreader plate.  The spreader plate keeps the harness from pinching in too much on the pilot and protects the pilot’s backside.  Before takeoff, the bottom end of the control stick is pinned to the spreader plate forming a hinged joint.  This connection takes place next to the pilot’s backside very close to her personal center of mass.  Two additional support lines or ropes pass through idler rollers on the out sides of the control stick.  The ropes are used to even out the support of the pilot’s weight while allowing the pilot to pivot back and forth between the upright and prone position.

     The outer parts of the control stick are made from two sections of rigid tubing.  The upper section is smaller in diameter than the lower section.  The upper section is sleeved by the larger diameter lower section.  Because the lower tube overlaps the upper tube, the control stick can retract and extend telescopically.  There is a hang loop on the inside of the control stick.  While flying the pilot’s weight is actually supported by the internal hang loop.  There is also a slightly longer internal aircraft cable.  The cable serves as a failsafe just in case the hang loop should break.  Stop rings are used to prevent the control stick from retracting or extending further than desired.  The stop ring that prevents the control stick from extending too far also serves as a backup.

     When a relative motion takes place between the pilot’s center of mass and the primary wings, the control stick has to stay pointed towards the pilot’s center of mass.  This is because the control stick is free to swing longitudinally and laterally in relation to the glider and the pilot hangs from the bottom end of the rigid control stick.  Therefore, as the angle of the primary wings change in relation to the pilot’s center of mass, it also changes in relation to the angle of the control stick from which the pilot is suspended.

     The control stick is linked mechanically to the tail wing by two push-pull tubes.  This setup causes the angle of the glider in relation to the control stick to determine the angle of the tail wing in relation to the primary wings.  In other words, the nose up or nose down pitching action of the glider in relation to the control stick and pilot forces the tail wing to pitch up or down in relation to the primary wings.

1. From trim speed, as turbulence and or the pilot cause the primary wings to raise their angle of attack, they pitch nose up relative the angle of the control stick the pilot hangs from.
2. The increase in angle between the primary wings and the control stick forces the tail wing to lower its trailing edge.
3. The hinging action of the tail wing takes place at its leading edge.  Thus, when the tail wing hinges its trailing edge down, it actually raises its pitch angle in relation to the primary wings.
4. Raising the pitch angle of the tail wing in relation to the primary wings causes the tail wing to create more lift.
5. Because more lift is produced at the aft end of the glider, the overall center of lift moves rearward.
6. The center of lift moves in the same direction as the center of gravity.
7. The center of lift travels further rearward than the center of gravity does.
8. Transposition of the center of lift to behind the center of gravity causes the pitching moment force to become negative.
9. The negative pitching moment force tends to return the primary wings and glider back to their trim speed angle of attack.
10. From trim speed, as turbulence and or the pilot cause the primary wings to lower their angle of attack, they pitch nose down relative to the angle of the control stick the pilot hangs from.
11. The decrease in angle between the primary wings and the control stick forces the tail wing to raise its trailing edge.
12. The hinging action of the tail wing takes place at its leading edge.  Thus, when the tail wing hinges its trailing edge up, it actually lowers its pitch angle in relation to the primary wings.
13. Lowering the pitch angle of the tail wing in relation to the primary wings causes the tail wing to create less lift.
14. Because less lift is produced at the aft end of the glider, the overall center of lift moves forward.
15. The center of lift moves in the same direction as the center of gravity.
16. The center of lift travels further forward than the center of gravity does.
17. Transposition of the center of lift to in front of the center of gravity causes the pitching moment force to become positive.
18. The positive pitching moment force tends to return the primary wings and the glider back to their trim speed angle of attack.

     In the same duration of time, the center of lift always travels further than the center of gravity.  Because the center of lift travels faster than the center of gravity, the center of lift separates a longer extent from the center of gravity as they progress further away from the glider’s trim speed angle of attack.  The longer the distance between the center of lift and the center of gravity becomes, the stronger will be the pitching moment force that tends to return the glider back to its trim speed angle of attack.  This happens because of an increase in mechanical advantage.  Because the pitching moment force increases with distance traveled, the pilot has to exert a stronger force to make the primary wings and glider raise or lower their angle of attack to a greater degree from the glider’s trim speed angle of attack.  Thus, the pilot experiences positive feedback pitch stability.

     This method for achieving pitch stability is unusual because it is actuated by gravity.  Because it is gravity activated, it takes place as a naturally occurring automatic process.  Thus, when the pilot is not applying a control input, the pitch stability is maintained by autopilot-like pitch control.

The Kite Flyer

     William Beeson an American pioneer of untethered or free flight was granted US patent number 376937 in 1888.  His invention was entitled, “The Flying Machine.”  The flying machine combined weight shift with aerodynamic control.  The flying machine had an unusual method for providing the pitch stability of an untethered kite or unmanned hang glider.

     The top end of a pendulum was connected to the keel of the kite with a hinged joint.  The bottom end of the pendulum was weighted and gravity forced the pendulum to hang nearly vertical.  There was an elevator hinged to the aft end of the kite.  A push-pull stick linked the pendulum to the elevator.  When the kite’s angle of attack was disturbed by turbulence, the angle of the kite changed in relation to the angle of the pendulum.  This forced the elevator to hinge up or down in relation to the kite.  The pitching action of the elevator relative to the kite caused the center of lift to move in the same direction but further than the center of gravity.  That resulted in a sequential transposition of the center of lift with the center of gravity.  Thus, the pitching moment force had a tendency to return the kite back to its trim speed angle of attack when disturbed by turbulence.

     Most movable horizontal airfoil surfaces located behind the wing are called elevators.  Elevators are customarily used to provide pitch control not pitch stability.  However, because the elevator of William Beeson’s Flying Machine was mechanically linked to the pendulum, the elevator was actuated by gravity.

     This method for achieving pitch stability was unusual because it was actuated by gravity.  Because it was gravity activated, it took place as a naturally occurring automatic process.  Thus, the pitch stability was maintained by autopilot-like pitch control.

     Gravity causes a pendulum to hang vertically.  When flying a weight shift hang glider, the pilot hangs like the weight on the end of a pendulum.  The pilot moves the glider in relation to her hanging or pendulous position by exerting force against the glider.  Due to gravity, once the control input is no longer being applied and the inertial forces have subsided, the pilot settles back into hanging nearly vertical just like the pendulum of the Kit Flier’s Flying Machine.  Therefore, when the pilot is not applying a control input the Ascender’s tail wing is automatically actuated by gravity just like the elevator on the Kite Flier’s untethered kite or unmanned hang glider.

     Ironically, William Beeson invented this method of achieving autopilot-like pitch stability over a hundred years before the author of this paper realized that the pitch stability of a planked winged hang glider could be acquired by reversing how the birds sacrificed their pitch stability.  A number of people attempted to recreate William Beeson kite flying experiments but failed.  This was possibly because their designs did not cause the center of lift to travel further than the center of gravity.  Hence, the sequential transposition did not occur and the gravity actuated pitch stability did not take place.  The ACE method of flight control does assures that the center of lift will outrun the center of gravity.  This is explained under the titles, “Hole Drilling Analogy,” “Applied Forces,” “Received Forces,” and “ACE Fights Fire with Fire.”

Hole Drilling Analogy

     It is important that the swinging motion of the control stick and pilot be impeded by the closed-loop circuitry of the linkage system.  Because it is not obvious why this happens it is worthwhile to present an analogy.  Therefore, we will compare drilling a hole in a steel plate with a hand drill and drilling the hole in the steel plate with a drill press.

     When using the hand drill, the steel plate is clamped to a workbench.  If the drill bit jams while drilling the hole in the steel plate and the plate resist being turned, the hand drill kicks back in the hand of the operator.  This happens because the transfer of forces is open-ended.  The hand drill scenario is analogous to flying a conventional weight shift hang glider.  When the pilot applies a force to move the glider and the glider resist she ends up swinging herself in relation to the glider.

      When using the drill press, the steel plate is clamped to the drill press itself.  This establishes a closed-loop circuit through which the transfer of forces must pass.  If the drill bit jams while drilling a hole in the steel plate, the confined forces kicks back against themselves.  Therefore, the applied force and the resistance force counteract against one another and cancel each other out.  That is because the transfer of forces is contained within the closed-loop circuitry of the drill press.  This is analogous to the Ascender’s linkage system.  When the pilot applies force against the glider and the glider resist, the interacting forces cancel each other out.  This tends to impede the swinging action of the control stick.  Thus, as the resistance increases so does the stiffness of the pilot’s pendulous position.  That allows the pilot to exert grater force to make the glider move in relation to herself and the control stick she hangs from.

     If the pilot’s center of mass were to swing too far in relation to the glider, the pilot plus glider center of gravity might travel further than the center of lift.  That could result in a temporary loss of gravity actuated pitch stability.  However, because the glider has to do most of the moving in relation to the control stick and pilot, the pilot’s center of mass does not actually travel very fare relative to the glider.  This explains why at normal flight speeds the center of lift always travels further than the center of gravity.  Therefore, the sequential transposition does take place and the glider’s unusual kind of pitch stability is maintained.

Adjustable Pitch Stability

     ACE provides pitch stability by using an automatic process to vary the amount of lift created by the tail wing.  For a given set of conditions, two factors determine how much the tail wing varies the amount of lift it creates.  One is the size of the tail wing selected for a specific flight and the other is how many degrees the tail wing pitches up and down in relation to the primary wings.

     The kinematics of the linkage system allows for a short range of adjustability.  One such adjustment permits the pilot to relocate the point of juncture where the push-pull tubes connect to the control stick.  The control stick swings longitudinally where it connects to the keel tube.  The distance between where the control stick connects to the keel tube and where the push-pull tubes connect to the control stick determines how much the tail wing pitches up and down when a relative change in angle takes place between the glider and the control stick the pilot hangs from.

     The further the tail wing pitches in relation to the glider, the more the lift it creates will vary.  The greater the lift variation created by the tail wing, the further the center of lift outruns the center of gravity.  The further the center of lift progresses away from the center of gravity, the stronger the pitching moment force becomes.  This happens because of increasing mechanical advantage.  The stronger the pitching moment force becomes, the stronger the tendency for the glider to return to its trim speed angle of attack.  The stronger the tendency for the glider to return to its trim speed angle of attack, the more pitch stability it is understood to have.  Hence, the size of the tail wing selected before flight and the point of juncture where the push-pull tubes connect to the control stick, determines the glider’s pitch stability setting for the duration of a particular flight.

     The simple and swift method used to set the glider’s pitch stability allows the pilot to make last minute changes just before time to launch the glider.  Thus, the pilot may adjust the pitch stability to accommodate the weather conditions of each flight.  When flying conditions are intense, having enough pitch stability is crucial.  Hence, adjustable pitch stability can increase flight safety.  ACE reduces the usual fixed pitch stability compromise to coincide the special needs of every flight.

Note:  By installing a fiberglass compression spring with a VG-rope-like-setup, the pitch stability could be adjusted while in flight.  This would allow the pilot to adjust the glider’s pitch stability to accommodate the weather conditions while they were changing during the flight.  Even though this could be done, it is not necessarily recommended because of the small increase in complexity.  The more complex a design becomes the more possible ways something might go wrong.

Variable Sizing

     Because the Ascender is mechanized by the linkage system, additional options are easy to implement.  Adjustable pitch stability is but one example.  Because the pitch stability is easily adjusted, the pilot may choose from a variety of different tail wing shapes and sizes.  Different tail wing designs may be chosen to accentuate different desirable flying attributes.

     The leading edge sailcloth of every tail wing is the same because they must all Velcro and safety pin to the same linkage system hardware.  However, different tail wing shapes and sizes require different sailcloth patterns, spar lengths, and color-coded battens.  Because the tail wing is quick and easy to exchange, the pilot may choose which tail wing she prefers to fly with just before time to launch into flight.  The total or overall size of the glider is determined by the size of the tail wing selected.  Hence, variable sizing allows just one hang glider to serve as though it were several hang gliders of different sizes.  This benefit is gained without the expense and inconvenience of having to purchase and transport several different size hang gliders.  ACE reduces the usual compromise of having to fly in all wind conditions with one size hang glider.

Yaw Controls

     The pilot applies a roll control force and banks the glider by lowering the angle of attack of one primary wing segment while raising the angle of attack of the other one on the opposite side.  Thus, by interacting with one another the primary wings function as full wing-sized ailerons.  Applying the primary wings differentially causes an adverse yaw force.  This source of adverse yaw occurs in addition to the other known causes of adverse yaw.  Hence, an even greater yaw control force must be applied to counteract the combined or total adverse yaw force and coordinate the turn.

     ACE provides two methods for applying a yaw control force.  The first technique is to bank the primary wings and glider in relation to the horizon and the tail wing.  The second technique is to turn the tail wing and its rudder fin.  Both methods cause some of the tail wing’s downwash to be deflected off to one side or somewhat obliquely in relation to the glider’s direction of flight.  Accelerating air in one direction causes an equal reactionary force in the opposite direction.  Because the tail wing and rudder are located at the aft end of the glider, pushing air off to one side steers or yaws the glider in that direction.

     The pilot flies the glider wearing a harness attached to the bottom end of the lower control stick section.  The top end of the upper control stick section is connected to the keel tube.  The keel tube is mounted in nylon bushings and is free to rotate in relation to the primary wings and glider.  The tail wing is connected to the aft end of the keel tube.  Thus, as the primary wings and glider bank in relation to the horizon, they bank in relation to the pilot, control stick, keel tube, and tail wing.  Because the glider becomes banked in relation to the tail wing, the tail wing’s downwash is deflected off to one side in relation to the glider’s direction of flight.  That produces a yaw control force.  It feels to the pilot as though she swings her center of mass laterally and she does a little.  However, in actual practice the primary wings and glider do most of the banking in relation to the horizon and the tail wing.  Because the tail wing remains mostly parallel to the horizon, it continues to do work against gravity and provide a substantial amount of lift.

     The pilot flies in the prone position and hanging from the bottom end of the lower control stick section.  Because the lower section of the control stick overlaps its upper section, it is free to turn around the upper section.  The upper end of the lower control stick section has an adjustable slide with saddled spacers or standoffs mounted on each side of it.  The two push-pull tubes are bolted through gimbal or ball jointed rod ends to the outside ends of the standoff and to the leading edge of the tail wing.  The tail wing is connected with a single pin to the aft end of the keel tube.  That allows the tail wing to turn at its point of juncture to the keel tube.  As the pilot points her body to one side in relation to the keel tube, the lower control stick section turns along with her.  Turning the lower control stick section turns the standoffs.  This causes one push pull tube to push towards the tail wing and the other to pull away from the tail wing.  That turns the tail wing.  When the tail wing turns in relation to the keel tube, its vertical fin functions as a rudder.  Because the ends of the push-pull tubes are the same length and distance apart, when the pilot turns her body, she turns the tell wing and rudder in the same direction and for the same number of degrees.

     The techniques used to apply yaw control forces occur in response to the interactions that take place between the primary wings and the tail wing.  The pilot could bank the primary wings relative to the tail wing without turning the tail wing and its rudder.  The pilot would do this by swinging her center of mass laterally without turning her body in relation to the keel tube.  The pilot could turn the tail wing and its rudder without banking the primary wings in relation to the tail wing.  The pilot would do this by turning her body in relation to the keel tube without swinging her center of mass laterally.  Thus, it is possible for the pilot to apply either one of the two yaw control techniques independently of the other.  Even so, in actual practice both yaw control techniques are typically carried out concurrently in one fluid motion.  The pilot does this by swinging her center of mass laterally while turning her body in relation to the keel tube.  By blending both techniques correctly, the pilot counteracts the total amount of adverse yaw force and coordinates the turn.

     The manner in which pilot’s typically maneuver their bodies to perform coordinated turns when flying a conventional weight shift hang glider is the same as those used to apply both yaw control techniques when flying the Ascender.  The pilot pulls in with one hand while pushing out with the other hand to maneuvers her body in the manner needed to apply both yaw control techniques.  This works out perfectly because these are the same hand movements used by the plot to force the primary wings to hinge or pitch in opposite directions.  Thus, the same physical actions used to bank the glider also produces the yaw control force needed to counteract the adversely yaw force.

Control Surface Manipulations

     To prevent confusion, the pilot’s actions are described at this time as taking place separately.  However, they are actually carried out simultaneously as a combination of actions.  When a control input is being applied, it feels to the pilot as though she swings her center of mass in relation to the glider and she does a little.  Even so, most of the relative motion is actually the glider moving in relation to the pilot.

     For the Ascender to be both lightweight and have robustly structural integrity, it is essential that the primary wings be connected to the rest of the glider at their inside trailing edges in addition to their inside leading edges.  Hence, the trailing edges of the primary wings are connected to a rocker arm link located near the aft end of the keel tube.  This allows the primary wings to hinge in relation to each other at their leading edges while being securely attached to the glider at their trailing edges.  Because of the rocker arm link, the primary wing on one side of the glider cannot pitch in relation to the glider unless the other side becomes pitched to the same degree in the opposite direction.  The only way for both primary wings to change their angle of attack in the same direction is for the glider itself to raise or lower its overall angle of attack.  Therefore, when it is said that the primary wings raise or lower their angle of attack in unison, it is understood that the glider itself raises or lowers its overall angle of attack.

1. From trim speed, the pilot pushes out an equal distance with both hands in unison.

The pilot swings backward a little but mostly the primary wings raise their angle of attack in unison by raising the angle of attack of the glider itself.  This increases the degree of angle between the primary wings and the control stick.  That causes the tail wing to pitch nose up in relation to the primary wings by lowering its trailing edge.  The glider’s airspeed deaccelerates.

• The pilot pushes out further an equal distance with both hands in unison.

The same description stated above takes place until the glider’s airspeed slows to its minimum sink speed.  The glider descends through the ambient atmosphere as slow as possible over time.

• The pilot pushes out even further an equal distance with both hands in unison.

The same description stated above takes place until the glider slows to its stooping-flight speed.  The root section or central area of the primary wings and the tail wing becomes stalled.  That causes a large loss of lift and huge increase in drag.  Thus, the tail wing interacts with the primary wings to function as a spoiler and drag beak.  The outer and much larger extents of the primary wings continue to produce lift.  The glider keeps flying but descends at a very steep angle.  The tail wing goes into a flutter oscillation and vibrates the control stick the pilot hangs from.  This serves as a stall warning alarm.

• The pilot pushes out as far as possible an equal distance with both hands in unison.

The same description stated above takes place until the entire triadic wing becomes completely stalled and stops flying.  If the glider is close to the ground, the pilot who has already pivoted to the upright position, puts her feet down, and lands.  If the glider is high above the ground, it falls into a steep nosedive.  The nosedive is the glider’s stall recovery.

• From trim speed, the pilot pulls in an equal distance with both hands in unison.

The pilot swings forward a little but mostly the primary wings lower their angle of attack in unison by lowering the angle of attack of the glider itself.  The degree of angle between the primary wings and the control stick decreases.  That causes the tail wing to pitch nose down in relation to the primary wings by raising its trailing edge.  The glider’s airspeed accelerates.

• The pilot pulls in further an equal distance with both hands in unison.

The same description stated above takes place until the glider accelerates to its best glide speed.  The tail wing becomes aligned with the downwash streaming from the primary wings.  The tail wing essentially stops creating lift and causes very little drag.  The glider achieves its longest glide ratio relative to the ambient atmosphere.

• The pilot pulls in even further an equal distance with both hands in unison.

The same description as stated above takes place until the glider accelerates to an even faster airspeed.  The tail wing hinges its trailing edge up out of alignment with the downwash streaming from the primary wings.  That deflects air up and causes a downward force at the aft end of the glider.  Thus, the tail wing interacts with the primary wings to function as though it were the reflexed trailing edge of the primary wings.  This is the glider’s dive recovery.

• The pilot pulls in with one hand while pushing out an equal distance with the other hand.

The hand that pulls in lowers the angle of attack of the primary wing on its side of the glider.  The hand that pushes out raises the angle of attack of the primary wing on its side of the glider.  Thus, the primary wings interact with each other differentially to function as full wing-sized ailerons.  A roll control force is applied.  The pilot swings her center of mass laterally a little but mostly the primary wings and glider bank in relation to the horizon, pilot, control stick, keel tube, and tail wing.  The downwash that flows from the tail wing becomes oblique in relation to the glider’s direction of flight.  A yaw control force is applied.  Because the tail wing remains mostly parallel to the horizon, it continues to do work against gravity and produce a substantial amount of lift.

• The pilot points her body to one side or turns in relation to the keel tube and glider.

The bottom section of the control stick turns along with the pilot in relation to the keel tube.  That causes one push-pull tube to push towards the tail wing while the other pulls away from the tail wing.  That turns the tail wing and its vertical rudder fin.  This deflects air off to one side in relation to the glider’s direction of flight.  A yaw control force is applied.

     The above statements are true but somewhat misleading.  They make the ACE method of flight control seem much more restricted than it really is.  This is because they do not describe the many ways in which the pilot may apply all three-axis of flight control concurrently in one fluid motion.

     The linkage system’s rocker arm link will not allow one primary wing to pitch in relation to the glider unless the other becomes pitched to the same degree in the opposite direction in relation to the glider.  This eliminates the instability associated with asymmetrical manipulation of the primary wings.  However, it does not prevent the pilot from applying pitch control, roll control, and yaw control simultaneously with the same graceful maneuvering of her body.

     When the pilot moves her hands either forwards or rearward an equal distance in unison, she controls the angle of attack of the glider but does not alter the bank angle of the glider.  When the pilot pull in with one hand while pushes out an equal distance with the other hand, she controls the bank angle of the glider but has little effect on the glider’s angle of attack.  For the pilot to control both the angle of attack of the glider and the bank angle of the glider at the same time, all she has to do is moves her hands an unequal distance in relation to each other.

     For example, suppose the pilot wants to initiate a left hand turn by lowering the overall angle of attack of the glider while banking the glider to the left.  One way to accomplish this is to hold the right hand in place while pulling in forcefully with the left hand until the left primary wing lowers its angle of attack by perhaps teen degrees.  In this scenario, the left primary wing segment pitches down five degrees in relation to the glider as the glider itself lowering its pitch angle by five degrees in relation to the right primary wing.  Because the pilot’s right hand did not permit the right primary wing to pitch up in relation to the glider, the glider had to pitch down in relation to the right primary wing.  In other words, the rocker arm link caused the glider to lower its overall angle of attack so that both primary wings could pitch in opposite directions the same number of degree in relation to the glider.  Therefore, the rocker arm link prevents the asymmetrical pitching of the primary wings while allowing three-axis of flight control to be applied simultaneously.

     In addition to the above example, the pilot could have pulled in with both hands while pulling in a further distance with the left hand.  That would have lowered the angle of attack of the glider even further while banking the glider to the left.  To raise the overall angle of attack of the glider while banking it to the left, the pilot would have to push out forcefully a further distance with the right hand than she pulls in with the left hand.  Banking the glider to the right instead of to the left is performed by switching the direction of the hand movements.  Because the pilot may apply a blend of control movements in one fluid motion, it feels as though she holds the primary wings in her respective hands.  Actually, she is connected to the primary wings through the linkage system.

Modus Operandi

     The ACE method of flight control provides for two different modes of operation with the same structural hardware mechanics.  The first mode of operation is called safe-mode.  In safe-mode, the rocker arm link is pinned to the keel tube.  This links the banking of the rocker arm link to the rotation of the keel tube.  Remember that the rocker arm link becomes banked when the primary wings pitch in opposite directions and the rotation of the keel tube is caused by the pilot swings her center of mass laterally.  Also, remember that the tail wing becomes banked by the rotation of the keel tube.  Therefore, when the pilot forces the primary wings to pitch in opposite directions, she also forces her center of mass to swing laterally and vice versa.  In safe-mode, the rocker arm link essentially becomes the leading edge of the tail wing.  This is because when the rocker arm link banks to one side, the tail wing has to move synchronously with the rocker arm.

     Safe-mode works out because the hand movements used to make the primary wings pitch in opposite directions are also the same as those used by the pilot to swing her center of mass laterally.  While in safe-mode, the pilot cannot bank the glider in relation to the horizon without causing the tail wing to bank in the opposite direction relative to the glider.  In other words, the pilot cannot initiate a turn without applying a yaw control force to counteract at least some of the adverse yaw force.  Thus, safe-mode helps to prevent inexperienced pilots from making uncoordinated turns.  Safe-mode makes the glider’s flight more coordinated by providing a kind of yaw-roll coupling,

     The second mode of operation is called freed-mode.  In freed-mode, the rocks arm link rocks around the keel tube but it is not pinned to the keel tube.  The rocker arm link does not serve as the leading edge of the tail wing.  In other words, the pilot may swings her center of mass laterally and turn the keel tube, which banks the tail wing without rocking the rocker arm link or forcing the primary wings to pitch in opposite directions.  In addition, freed-mode permits the pilot to pitch the primary wings in the opposite direction, which causes the glider to bank to one side without forcing the pilot’s center of mass to swing laterally.

     Despite freed-mode’s lack of yaw-roll coupling, how the pilot actually preforms turns in freed-mode is very similar to that of safe-mode.  However when in freed-mode, the pilot may vary the timing of the control inputs.  For example, the pilot might start out by hinging or pitching the primary wings in opposite directions and then swing her center of mass laterally a moment or two later.  The pilot might start out by swinging her center of mass laterally and then pitch the primary wings in opposite directions a moment or two later.  These momentary delays allow the pilot to play with the inertial, centripetal, and centrifugal forces she experiences when performing turns.  In freed-mode, the pilot is given more freedom to express her personal artistic stile of flying.

     The mechanization of the Ascender by the linkage system provides for both the safe and freed modus operandi.  By inserting a single modus quick pin, the glider is locked into safe-mode.  By extracting the modus quick pin, the glider is permitted to fly in freed-mode.  The pilot gets to decide just before time to launch into flight which modus operandi she prefers.

Note:  With a single spring-loaded pin and a VG-rope-like-setup, the pilot could switch from one modus operandi to the other while in flight.  This could be done easily but it is not necessary.

CONTROL SURFACE ENLARGEMENT

Avian Wings

     For a given set of factors, the ability for strong gusty winds to toss about a bird on the wing increases with the size of the bird’s wings in proportion to the size of their bodies.  Most species of soaring birds have wings that are enormous in comparison to their bodies.  These facts evoke the following questions.  How is it possible for soaring birds to stay in control when flying in severe turbulence?  How could birds have ever evolved wings that were proportionally big enough to become soaring birds in the first place?

     One answer to the previous questions has to do with how birds use their three versatile lift producing appendages.  Because birds utilize interaction between their wings to control flight, their wings also serve as their control devises.  Thus, birds utilize the entire outer surface area of their wings as control surfaces.

     For a given set of conditions, the amount of force that a bird can apply against the air to control flight depends on the size of the control surface area being used.  The wings of birds are their control devices.  Hence, the larger a bird’s wings become the bigger their control surfaces become.  The bigger the control surfaces become the greater the force that can be applied to control flight.

     Birds adapted to soaring flight by gradually evolving larger lift producing appendages.  Because the control surface area was enlarged at the same time and by the same amount as the wings, soaring birds were enabled to apply stronger control forces.  Hence, the principle of using their wings to function as both lift producing appendages and control surfaces had a tendency to compensate for the increased influence allowed to the wind by having bigger wings.  Therefore, avian-style interactive aerodynamic flight controls made it possible for some species of birds to evolve wings proportionally big enough for them to become predominantly non-flapping birds.

Ascender’s Triadic Wing

     Control forces applied by the pilot and pressures caused by strong gusty winds sometimes compete for dominance over the glider.  One of the most decisive factors involved in the struggle is the size of the wing.  The ACE method of flight control takes advantage of the same principle that explains how it was possible for some species of birds to have evolved wings that were proportionally big enough to become soaring birds.

     For a given set of conditions, the amount of force that a pilot can apply against the air to control flight depends on the size of the control surface areas being used.  The Ascender’s wing segments form the outer surface area of its triadic wing.  Besides serving as lift producing airfoils, interaction between the wing segments causes them to function as aerodynamic control devices.

     Because the control surface area is enlarged by the same amount as the triadic wing, the pilot is enabled to apply stronger control forces.  Hence, the principle of using the wing segments to function as both lift producing airfoils and control surfaces has a tendency to compensate for the increased influence allowed to the wind by having a larger wing.  Therefore, the unification of weight shift with avian-style interactive aerodynamic flight control makes it possible for humans to fly an extra-large hang glider with a much bigger wing.

FLIGHT CONTROLS

Control Strength Evaluation

     When a control input is being applied, relative motion takes place between the pilot and the glider.  One way to evaluate flight control effectiveness is based on how far the pilot has to swing her center of mass to make the glider respond as desired.  Weak flight control is indicated by the pilot doing most of the moving in relation to the glider.  Strong flight control is indicated by the glider doing most of the moving in relation to the pilot.  Powerful flight control is demonstrated by the glider being made to do most of the moving even though the glider is extra-large and the turbulence becomes intense.

Simplistic Statement

     Extreme simplification of a rather complex subject leads to the following generalizations.  These rules-of-thumb are not altogether true but are useful for the purpose of comparison.

• The flight controls of a conventional hang glider are operated by moving the center of gravity in relation to the center of lift (weight shift).
• The flight controls of birds and sailplanes are operated by moving the center of lift in relation to the center of gravity (aerodynamic control).
• The flight controls of the Ascender are operated by the concurrent translocation of both the center of lift and the center of gravity (duality of weight shift plus aerodynamic control).

CONTROL COMPARISON

Weight Shift Alone

     With weight shift as the principal method used to apply flight control, the pilot swings about freely beneath the wing.  The pilot cannot apply a strong force against the glider because she does not have a firm position from which to exert force.  Higher wind speeds and turbulence can make it difficult to exercise enough control especially when flying a larger size hang glider.

     Because the pilot dangles from the end of a flexible hang loop, she depends mostly on her inertial resistance to force the glider to move in relation to her body.  Because the pilot has more mass than the glider, she has more inertial resistance than the glider.  Hence, the glider usually does most of the moving in relation to the pilot.  However, if weather conditions and or the size of the glider prevent the glider from moving readily in relation to the pilot, the pilot ends up doing most of the moving in relation to the glider.  The pilot only has a short distance that she can swing her center of mass to activate the desired response.  For the pilot to have adequate control over the glider her inertial resistance needs to be about twice that of the glider.

     For anything to have inertia, it must have mass.  Due to the Earth’s gravity, an increase the mass is increase the weight.  Hence, to have adequate control over a standard weight shift hang glider, the pilot’s weight needs to be about twice that of the glider.  In conclusion, with weight shift as the principal method used to apply flight control, the size of the glider is limited by inertial dependency, and having a heavy wing loading cannot be avoidable.

Weight Shift plus Aerodynamic Control

Applied Forces

     The ACE method of flight control causes weight shift to work in conjunction with avian-style interactive aerodynamic flight control.  A closed-loop chain of links referred to as the linkage system makes this possible.  One integral link of that chain is the control stick mentioned previously.  Because the pilot hangs from the bottom end of a rigid control stick, the control stick has to stay pointed towards her center of mass when a relative change in angle takes place between the glider and the pilot’s center of mass.  Hence, a change in angle between the glider and the pilot is also a change in angle between the glider and the control stick from which the pilot is suspended.  Any relative change in angle that takes place between the glider and the control stick, forces the wing segments to be manipulated in relation to each other.  The interactions that take place between the wing segments can create strong aerodynamic control forces.

     Aerodynamic control forces occur when control surfaces pushing against the air.  The wing segments that make up the triadic wing are the Ascender’s control surfaces.  When the wing segments push against the air, the air presses back against them with an equal and opposite reactionary force in compliance with the third low of motion.  Hence, air pressures oppose manipulation of the wing segments.

     Resistance to the manipulation of the wing segments causes resistance to the movement of the control stick mechanically linked to the wing segments.  In different words, the resistance makes it more difficult for the control stick to swing in relation to the glider.  Resistance to the motion of the rigid control stick inhibits the swinging actions of the pilot attached to the bottom end of the control stick.  Impedance to the pilot’s pendulous motion causes her pendulous position to become firmer.  The stronger the resistance to the pilot’s exertions, the firmer the pilot’s pendulous position becomes.  Therefore, the inertial resistance of the pilot’s body is thereby augmented by increased pendulous resistance.  Having a firmer position from which to pull and push off from enables the pilot to exert stronger control forces.

Received Forces

     When the triadic wing is struck by a gust of wind, its wing segments receive the blast.  This air pressure or force transmits from the wing segments back to the control stick.  The bottom end of the control stick then pushes against the pilot at its point of juncture to the pilot.  The pilot feels how the glider’s base tube and control stick attempt to travel in relation to each other.  The control stick and base tube always attempt to move in opposite directions.  Either they try to move towards each other or they try to move away from each other.  When the pilot wants to prevent the wing segments from being manipulated by turbulence, all she has to do is prevent her hands from moving in relation to her center of mass.  That causes the received forces to counteract one another.  They cancel each other out because the linkage system forms a closed-loop circuit with the pilot positioned within the interplay of forces.

     Any received force that tries to manipulate the wing segments also attempts to move the control stick mechanically linked to the wing segments.  Any force that attempts to swing the control stick in one direction tends to inhibit the control stick from swinging in the opposite direction.  In different words, it becomes more difficult for the control stick to swing in relation to the glider.  Resistance to the movement of the rigid control stick impedes the swinging actions of the pilot attached to the bottom end of the control stick.  Impedance to the pilot’s pendulous motion causes her pendulous position to become firmer.  The stronger the received forces trying to manipulate the wing segments, the firmer the pilot’s pendulous position becomes in the direction needed to oppose the received forces.  Therefore, the inertial resistance of the pilot’s body is thereby augmented by increased pendulous resistance.  Having a firmer position from which to pull and push off from enables the pilot to exert stronger control forces.

ACE Fights Fire with Fire

     The outcome is always the same for either applied or received forces.  Whether the pilot’s exertions are resisted by aerodynamic pressures or aerodynamic pressures are resisted by the pilot, all resistance is exploited by the ACE method of flight control to increase the potential to apply stronger control forces.  This increase in potential becomes automatically available on demand.

     When flight conditions allow the glider to react readily to control inputs, the pilot only has to swing her center of mass a short distance to make the glider respond as intended.  In other words, it is easy for the pilot to make the glider move in relation to her center of mass.  However, when flight conditions cause the glider to resist being controlled, the ACE method of flight control still assures that the glider will have to do most of the moving in relation to the pilot.  This is because any form of resistance impedes the swinging action of the control stick and the pilot hanging from the bottom end of the control stick.  That makes the pilot’s pendulous position firmer in the opposite direction to the resistance and for the duration of the resistance.  The stronger the resistance becomes, the firmer the pilot’s pendulous position becomes.  By having a firmer position from which to apply force, the pilot is enabled to exert stronger control forces.  Thus, the pilot is actually being empowered by the resistance to the control effort itself.

     Every time the pilot moves her hands in relation to her center of mass, a relative motion has to take place between the glider and the pilot’s center of mass.  Hence, the more the pilot is prevented from moving in relation to the glider, the more the glider has to move in relation to the pilot.  Therefore, the ACE method of flight control guarantees that the pilot will always be empowered to apply a greater control force as and whenever needed.

     Because the potential to apply more control over the glider is derived from the resistance to the control effort, more becomes spontaneously available on demand.  Paradoxically, the ACE method of flight control literally uses resistance to control as its tactic to overpower resistance to control.  Hence, the saying, “ACE fights fire with fire.”

Elimination of Inertial Dependency

     Aerodynamic control is applied by forcing a relative motion to take place between the wing segments.  Manipulation of the wing segments occurs when a relative motion takes place between the glider and the control stick.  A relative motion takes place between the glider and the control stick when the pilot moves the glider in relation to her center of mass.  A relative motion always takes place between the glider and the pilot’s center of mass when the pilot moves her hands in relation to her center of mass.  Therefore, aerodynamic control forces are always applied whenever the pilot moves her hands in relation to her center of mass.

     Aerodynamic control forces are stronger and have a greater effect on flight control than is possible by weight shift.  Hence, ACE technology eliminates inertial resistance as the principal method used to apply flight controls.  Because inertial dependency is eliminated, it is no longer compulsory for the pilot to weigh more than the glider.  For so long as a relative motion is taking place between the glider and the ambient atmosphere, the pilot will always have aerodynamic controls at hand.

     In conclusion, because aerodynamic controls work in conjunction with weight shift, the size of the glider is not limited by inertial dependency and having a heavy wing loading can be avoided.  That makes it practical to fly an extra-large hang glider with a lighter wing loading.  This makes high altitude soaring flights much easier to achieve.

Power Steering

     Because the pilot is attached to the bottom end of the control stick and because the control stick is a rigid lever arm, the pilot applies force to control the glider from an already leveraged position.  Due to the mechanical advantage involved, a weak input applies a strong force, and a strong input applies a powerful force.  Hence, the ACE method of flight control provides a sort of three-dimensional power steering.  This makes it easy for the pilot to manipulate the wing segments even when the glider is extremely large and the turbulence is severe.

     Because of the mechanical advantage, the pilot must move her hands a further distance to manipulate the wing segments to a lesser degree.  This keeps the control response from being too quick for human reflexes and it helps to prevent the pilot from over controlling the glider.

Control Summary

     For the reasons explained above and others yet to be revealed, the overpowering ACE method of flight control subjugates the glider to the pilot’s position of dominance.

1. ACE integrates weight shift with avian-style interactive aerodynamic flight control.  This duality exploits the concurrent translocation of both the center of lift and the center of gravity.
2. ACE uses interaction between the wing segments to provide aerodynamic flight control.  This causes flight control forces to increase along with the size of the triadic wing.  That makes it possible for humans to fly an extra-large hang glider with a much bigger wing.
3. ACE augments inertial resistance with increased pendulous resistance.  That enables the pilot to apply stronger control forces whenever needed.
4. ACE literally uses resistance to control as its tactic to overcome resistance to control.  This makes the potential to apply stronger control forces spontaneously available on demand.
5. ACE eliminates inertia dependency as the principal method for applying control forces.  This makes it practical to fly an extra-large hang glider with a lighter wing loading.
6. ACE takes advantage of the pilot’s already leveraged position.  This makes it easy for the pilot to manipulate the wing segments even in severe turbulence.  It keeps the control response from being too quick for human reflexes and helps prevent the pilot from over controlling the glider.
7. ACE causes the glider to do most of the moving in relation to the pilot even when the glider is extra-large and the flying conditions are extreme.  That demonstrates powerful flight control.
8. ACE makes hang gliding safer by providing immediate potentiated three-axis flight control, with just a negligible reduction in stability.

Benefits of Amplified Flight Control

     The necessity to maintain flight control dictates the upper limit to the size of the hang glider.  The Ascender’s obedient and responsive attributes makes it advantageous to fly an extra-large hang glider while enjoying enhanced flight control at the same time.  Flying a larger size hang glider with a bigger wing provides a lighter wing loading.  Wings having a lighter wing loading produce a better minimum sink rate.  Slower decent through the air requires less updraft velocity to achieve high altitude soaring success.  Descending slower through the air results in topping out higher when soaring in ridge lift and climbing out faster when working thermals.

     Gliders with a lighter wing loading can fly slower before a stall ensues.  When flight speed occurs at a slower airspeed it makes launching and landing less difficult and safer.  Flying slower while turning carves smaller diameter circles.  Because smaller turns can be made without having to bank the glider as much, the minimum sink rate is improved.  The ability to execute tighter turns facilitates circling within the thermal’s core zone.  Because the thermal’s core zone rises faster than the rest of the thermal, spending more time within the core zone hastens the ascent.

     When it comes to the slower airspeed requirement of a foot launched and landed hang glider, a good method to attain soaring flight is to increase flight control.  On those days when the updrafts are very weak, soaring flight is not possible unless the glider has an unusually light wing loading with an exceptionally slow descent rate.  To have those advantages, a very large wing is essential.  The ACE method of flight control fulfills the need to fly an extra-large hang glider while providing accelerated three-axis flight control simultaneously.

     On those days when the updrafts are strong, flying a larger size hang glider with a lighter wing loading is not necessary to soar.  Even so, when the updrafts are stronger, other flight conditions are typically stronger as well.  Intense and gusty winds can make it more difficult to keep the glider under control.  The ACE method of flight control diminishes that problem by providing powerful three-axis flight control.

     There are some visible air movement indicators but the air itself is invisible.  The severity of turbulence can change over time and vary at different altitudes.  Because flight control is substantially increased with only a negligible decrease in stability, the pilot gains an improved ability to cope with unpredictable weather conditions.  Because all human flight is inherently dangerous, nothing is of more important than flight safety.  Hence, safety is the paramount design criterion.  ACE utilizes amplified three-axis flight control as its strategy to mitigate the risk.

Modular Construction

     Because the Ascender has a segmented triadic wing, it may be structured in several different ways.  The primary wings could be rigid and have a hard shell-like outer surface or they could be flexible and be made from sailcloth, tubing, and battens.  A third alternative is called the D-tube leading edge method of construction.  With the D-tube method, the leading edges are rigid but the remainder of the wing is made from flexible materials.

     All of the movable joints and articulation that take place in the triadic wing are located within the mainframe hardware of the linkage system.  The triadic wing is assembled by sliding, snapping, and safety pinning the wing segments to the mainframe hardware.  Thus, the mechanics devised to make rigid wing segments manipulate can also be used for flexible wings.  Hence, a hang glider made with any of the three constructional methods can be mechanized by the same linkage system hardware.  There are advantages and disadvantages to whichever method of construction that might be chosen.  It would be too confusing to explain them all.  For the purposes of this discussion, the primary wings will be rigid having a hard shell-like outer surface while the tail wing will be flexible and be made of sailcloth, spars, and color-coded battens.

     Handmade hang gliders require well-trained and skilled artisans to assure the quality of the product.  It is labor intensive, time consuming, and expensive to build hang gliders in a series of single customized products.  Because the triadic wing is segmented, its wing segments can be manufactured as standardized interchangeable parts.  Hence, the Ascender may be mass-produced in collective runs of prefabricated modular units.  This is conducive to a semi-automated process.  Therefore, the Ascender should be less expense to manufacture.

     Because the wing segments are interchangeable modules, they are easy to replace.  It takes about the same amount of time to exchange a broken wing segment with a replacement as it does to setup the glider.  Hence, if just one wing segment is damaged beyond repair, it is only necessary to purchase another wing segment and avoid having to buy another entirely new hang glider.

     Over time, the hang glider manufacturer will surely make incremental design improvements.  The owner of an older model hang glider may choose to modernize her hang glider by replacing the older wing segments with an up to date set.  By continuing to use the same hardware, the pilot can upgrade her hang glider without having to buy the whole hang glider.

Breakaway Design Scheme

     Because the triadic wing is cantilevered, the greatest stresses are focused to the junctures within the linkage system’s mainframe hardware.  Besides allowing swivel actions to take place, the movable parts at these focal point junctures serve as shear pins.  When an outright crash occurs, they first bend and then snap apart.  While the triadic wing is crunching in and breaking into, the glider and pilot are being slowed down.  Thus, the maximum magnitude of the impact is lowered by lengthening the interval of time it takes to come to a complete stop.

     The breakaway design scheme is not expected to prevent the glider from being destroyed.  However, it is hoped that the sacrificial loss of the glider will diminish the likelihood of injury to the pilot.  The best-case scenario for an outright crash would be the complete destruction of the glider with the pilot walks away uninjured.

Lengthened Airspeed Range of Efficient Flight

     When not considering travel distance over land but flight relative to the ambient atmosphere, the most efficient flying takes place at and between the best glide speed and minimum sink speed.  The Ascender’s tail wing interacts with the primary wings to function as an active partially slotted plain flap.  How flaps lengthen the airspeed range of efficient flight is well understood.  It does not demand repeating at this time.  However, there is a process unique to the ACE method of flight control that is worthwhile explaining.

     The ACE method of flight control makes use of weight shift and aerodynamic control.  When applying pitch control, both the center of lift and the center of gravity are translocated.  The wing loading of the primary wings and the drag causes by the tail wing vary greatly.  The ACE method of flight control makes use of these variables to lengthen the airspeed range of efficient flight.

     By pulling in the pilot lowers the angle of attack of the primary wings, moves her center of mass forward a little more underneath the primary wings and raises the trailing edge of the tail wing.  Raising the trailing edge of the tail wing lowers its pitch angle in relation to the primary wings.  Lowering the pitch angle of the tail wing in relation to the primary wings causes the tail wing to produce a decreased proportion of the total required lift.  Hence, the primary wings have to produce more of the total required lift.  This increases the wing loading of the primary wings.  The wing loading of the primary wings is also increased by the pilot’s center of mass being more underneath the primary wings.  It tends to balance out for the pilot’s weight to be more under the primary wings because the primary wings are creating more lift.  The glider flies faster because the primary wings have a lower angle of attack, the primary wings have a heaver wing loading, and the tail wing causes less drag.

     When the Ascender is flying at its best glide speed, the tail wing is aligned with the downwash streaming from the primary wings.  Hence, the tail wing area of the triadic wing essentially stops creating lift.  Even though the actual size of the triadic wing does not change, the surface area being used to produce lift is effectively smaller.  Therefore, the Ascender preforms more like a virtually smaller size hang glider with a heaver wing loading.  This causes the best glide speed to occur at a faster airspeed.  By achieving a faster best glide speed, the glide ratio is extended.

     By pushing out the pilot raises the angle of attack of the primary wings, moves her center of mass rearward a little less underneath the primary wings, and lowers the trailing edge of the tail wing.  Lowering the trailing edge of the tail wing raises its pitch angle in relation to the primary wings.  Raising the pitch angle of the tail wing in relation to the primary wings causes the tail wing to produce an increased proportion of the total required lift.  Hence, the primary wings produce less of the total required lift.  This decreases the wing loading of the primary wings.  The wing loading of the primary wings is also decreased by the pilot’s center of mass being less underneath the primary wings.  It tends to balance out for the pilot’s weight to be less under the primary wings because the primary wings are creating less lift.  The glider flies slower because the primary wings have a higher angle of attack, the primary wings have a lighter wing loading, and the tail wing causes more drag.

     When the Ascender is flying at its minimum sink speed, the tail wing has approximately a positive fifteen-degree angle of attack relative to the downwash it encounters streaming from the primary wings.  Hence, the tail wing area of the triadic wing essentially creates its maximum amount of lift.  Even though the actual size of the triadic wing does not change, the surface area being used to produce lift is effectively larger.  Therefore, the Ascender preforms more like a virtually larger size hang glider with a lighter wing loading.  Achieving a lighter wing loading allows the minimum sink speed to occur at a slower airspeed and the rate of descent is reduced.

     Interaction of the tail wing with the primary wings enhances both the glide ratio and the minimum sink rate.  That provides for the best of both worlds.  ACE reduces the usual non-articulated design compromise between slower and faster airspeeds.

PLANFORM COMPARISON

Sweptback Planform

     When a standard sweptback hang glider flies into an updraft, its nose is knocked up.  That raises its angle of attack, which causes the wing to become more misaligned with the change in air current direction.  When a standard sweptback hang glider flies into a downdraft, its nose is knocked down.  That lowers its angle of attack, which causes the wing to become more misaligned with the change in air current direction.  Sweptback hang gliders react in this manner because the leading nose area of the wing enters the change in air current direction before the trailing wing tips.  Thus, a sweptback hang glider reacts against changes in vertical air movements as they are encountered.  Flying through turbulence cause a sweptback glider to be knocked up, dropped, then slammed up, and dumped again repeatedly.  Flying faster only increases the pounding.

Planked Winged Planform

     Because the primary wings of the Ascender are planked wings with their center of lift in an essentially straight line, they react to changes in vertical air movement differently than wings having a sweptback planform.  When the primary wings of the triadic wing fly into an updraft, they tend to lower their angle of attack thereby aligning with the change in air current direction.  When the primary wings of the triadic wing fly into a downdraft, they tend to raise their angle of attack thereby aligning with the change in air current direction.  Thus, the planked primary wing segments of the triadic wing have a tendency to wind-vane or merge into alignment with the air currents as they are encountered.

     The primary wings receive less impact because they have less of a tendency to oppose the turbulent air currents.  Because the Ascender is effected less by turbulence it inherits some naturally occurring pitch stability.  Because the primary wings receive less impact from wind gust, the glider and pilot experience a smoother ride.  This is especially the case when flying at faster airspeeds.  The Ascender flies more efficiently because going with the flow consumes less energy than pounding through the turbulence.

Articulated Versus Fixed

     When a wing experiences rising airflow on one side and sinking airflow on the other, the side that enters the updraft receives an upward push while the side that enters the downdraft receives a downward push.  Thus, the forces involved attempt to bank and thereby turn the glider away from the updraft or lift and towards the downdraft or sink.  This is detrimental to the purpose of soaring.  Hence, the pilot that flies a conventional non-articulated winged hang glider must struggle to prevent being pushed in the wrong direction for soaring.

     When the Ascender’s triadic wing experiences rising airflow on one primary wing segment and sinking airflow on the other, the primary wing that encounters the updraft tends to lower its angle of attack while the primary wing that encounters the downdraft tends to raises its angle of attack.  Two attributes of the triadic wing make this happen.  The first is that the primary wings are essentially planked wings that tend to merge into alignment with the air currents as they are encountered.  The second is that the primary wings may be allowed to pitch in opposite directions.

     When one primary wing segment has a lower angle of attack from that of the other, the side having the lowest angle of attack tends to rolls downward while the side having the highest angle of attack tends to rolls upward.  Thus, the Ascender has a tendency to bank towards the lift and away from the sink.  This compensates somewhat for the forces attempting to bank the glider in the wrong direction for soaring.  Because of this compensation, the pilot that flies the Ascender in normal flying conditions does not have to struggle to prevent being pushed out of the lift.

     Because of how the primary wings react to differences in vertical air movements on opposite sides of the glider, the same benefits that pertain to the pitch axis are also applicable where the role axis is concerned.  Hence, the Ascender receives less impact, experiences a smoother ride, inherits some roll stability, flies more efficiently, and is more enjoyable to fly than hang gliders having a non-articular sweptback planform.  ACE reduces the amount of physical exertion usually required to achieve soaring success.

     When the difference in vertical air movement on one side of the glider is small in comparison to that of the other, the primary wings have a weaker tendency to merge into alignment with the air currents.  This is acceptable because less compensation is needed.  When the difference in vertical air movement on one side of the glider is large in comparison to that of the other, the primary wings have a stronger tendency to merge into alignment with the air currents.  This is acceptable because more compensation is needed.  Thus, more compensation against being banked away from the lift and towards the sink becomes spontaneously available on demand.

     When the pilot wants to descend, she simply prevents the wing segments from pitching in relation to one another.  This causes the Ascender to fly more like a conventional non-articulated hang glider that is easily banks and turned away from the lift and towards the sink.  However, when the pilot wishes to ascend, she should assist some with how the primary wings naturally react to differences in vertical air movements on opposite sides of the glider.  In normal weather conditions, this comparatively easy to apply force is approximately the same whether the difference in vertical air movement on one side of the glider is either small or large in comparison to that of the other.

     How the primary wing segments react to the difference in vertical air currents informs the pilot which direction she should fly to locate a strong updrafts or thermals.  By helping the primary wings pitch a little further than they would normally do by themselves, the pilot steers the glider in the direction of the strongest lift.  All the pilot has to do is recognize the signals and go with the flow.  Simply stated, the Ascender is engineered to have an intrinsic inclination to soar!

Variable Washout

     When a wing is twisted in such a manner that the wingtips have a lower pitch angle than the center or root section of the wingspan, it is called washout.  The primary wings of the triadic wing are essentially planked wings.  They do not require very much washout during straight flight.  This is because the Ascender uses an entirely different method for providing pitch stability and for regulating stall progression than hang gliders having a sweptback planform.

     When the primary wings hinge or pitch in opposite directions, they are effectively increasing the degree of twist at the root section of the triadic wing.  This is a kind of variable washout.  This articulated twisting of the primary wings contributes to the total degree of washout over the length of the wingspan.  The variable washout adds to the fixed washout already present in the shape of the primary wings.  Thus, the total degree of washout is determined by how much the fixed washout is augmented by the variable washout.

     The triadic wing requires less fixed washout while flying straight because its fixed washout is supplemented by variable washout when initiating curved flight.  When the Ascender is flying straight, the triadic wing has only a few degrees of fixed washout because the primary wings are parallel to one another.  By having less washout, a greater percentage of the wingspan flies at its optimum angle of attack during straight flight.  That improves straight flying efficiency.

     While turning, the wingtip on the inside of the turn flies slower than the rest of the wing.  Hence, the inside wingtip typically stalls first.  Having more washout causes the inside wingtips to have a lower angle of attack.  When the inside wingtip has a lower angle of attack, the glider can reach a higher overall angle of attack before a wing tip stall ensues.  The ability to achieve a higher overall angle of attack allows the glider to execute slower turns.  Slower turns carve tighter turns.  The ability to circle within smaller thermals increases the percentage high altitude soaring flights.

     To execute a coordinated turn, the glider must be banked at least some to one side.  To begin the turning process, the pilot banks the glider by forcing the primary wings to pitch in opposite directions.  This pitching action effectively twists the triadic wing at its root section and thereby provides variable washout.  The variable washout adds the fixed washout increasing the total degree of washout over the length of the wingspan.  This variable washout causes the lowest angle of attack to be on the inside wingtip where it is needed the most.  This delays the wing tip stall and allows the glider to achieve a higher overall angle of attack when preforming curved flight.

     When the Ascender initiates curved flight, the triadic wing has both fixed washout and variable washout because the primary wings have different angles of attack.  By having more washout, a greater percentage of the wingspan flies at its optimum angle of attack during curved flight.  That improves curved flight efficiency.

     Having less fixed washout improves straight flight but then curved flight suffers.  Having more fixed washout improves curved flight but then straight flight suffers.  The ACE method of flight control decreases the degree of washout when flying straight and increases the degree of washout when initiating the turn.  Therefore, ACE provides for the best of both worlds.  ACE reduces the usual fixed washout design compromise between straight flight and curved flight.

Landing Approach

     Most of the time when soaring, the tail wing flies in the downwash that streams from around the root section of the primary wings.  The tail wing experiences a lower apparent angle of attack due to the declivity of the downwash that flows from the primary wings.  This allows the tail wing to have a higher pitch angle than the primary wings without stalling.  However, this changes when the root section of the primary wings becomes stalled.

     As the primary wings raise their angle of attack, the linkage system forces the tail wing to lower its trailing edge thereby raising its pitch angle in relation to the primary wings.  At a specific critical angle of attack, the root section of the primary wings becomes stalled.  This disrupts the continuity of the downwash passing around the root section of the primary wings to the tail wing.  That causes the tail wing to become stalled because its angle of attack is now too high for the direction of the airflow it experiences.

     It could be argued that, the tail wing becomes stalled first and that causes the root section of the primary wings to become stalled.  This is based on the theory that stalls occur when there is too great of a difference in air pressure between the top and bottom surfaces of a wing.  That makes for an interesting debate.  However, the important fact to remember is that, when either the root section of the primary wings or the tail wing becomes stalled, they will both become stalled.

     When the root section of the primary wings and the tail wing become stalled, that area of the triadic wing stops creating lift.  Even so, the glider continues to fly because the much larger outer extents of the primary wings continue to produce lift.  This partially stalled condition is called stooping-flight.  The term stooping-flight is used instead of the customary mush-mode term because of its likeness to how birds perform stooping-flight when descending at a very steep angle.

     Because the tail wing becomes stalled when performing stooping-flight, the center of lift moves from behind to in front of the center of gravity.  This causes a positive pitching moment force.  That would be pitch divergent and unacceptable if it were not for the huge increase in drag caused by the tail wing.  Once stalled the tail wing experiences a loss of lift and a big increase in drag.  This indicates that the tail wing is interacting with the primary wings to functions as a spoiler and drag brake.  Because this drag takes place behind and so far below the center of gravity, it attempts to force the glider to pitch nose downwards.  The negative pitching moment force counteracts and overpowers the positive pitching moment force.  Thus, when flying at the glider’s stooping-flight speed, the pilot has to push out harder to reach the higher angle of attack.  Because the pilot has to pushes out harder, she continues to experience positive feedback pitch stability.

     The struggle between the positive and negative pitching moment forces consumes a lot of the potential energy being transduced into kinetic energy.  Hence, stooping-flight is very inefficient where both the glide ratio and the minimum sink rate are concerned.  Even so, stooping-flight is ideal for descending at a very steep angle into the backend of a small clearing or small landing field.  This is especially desirable when the landing area is surrounded by tall obstructions such as trees and or power lines.

     When slowing down to stooping-flight speed, the root section of the primary wings and the tail wing both becomes stalled.  Thus, the airflow around the tail wing becomes perturbed.  That causes the tail wing to go into a flutter oscillation and vibrate the control stick the pilot hangs from.  Stooping-flight speed is slower than the minimum sink speed but slightly faster than the completely stalled airspeed.  Thus, stooping-flight serves as a stall warning devise or stall alarm.

     When flying at stooping-flight speed, turning the glider becomes somewhat sluggish but it does permit the landing approach to be remarkably steep without accumulating too much energy retention.  Because stooping-flight serves as a stall alarm, the pilot may stair-step down into the back end of a small landing field.  This is performed by pushing out until the control stick begins to vibrate and then quickly pulling back in again repeatedly.  Each stare step would probably causes a rapid and steep descent of approximately twenty-five feet.

Widened Flare Window

     Because the inertial resistance of the pilot’s body is augmented by increased pendulous resistance and because the pilot controls the glider from an already leveraged position, the opportune time to flare the glider or the flare window can be widened.  The Ascender has design features that allow it to be flared assertively at a much faster airspeed.  One feature is that the primary wings are planked wings with their center of lift in an essentially straight line.  Another is that the primary wings segments have a high aspect ratio.  Yet another is that the majority of the glider’s mass is in close proximity to the triadic wing’s center of lift.  Even another is that the tail wing segment is closely coupled with the primary wing segments.  Because of these combined attributes, the Ascender can be flared quickly enough and high enough that it becomes completely stalled before getting the chance to popup into a whipstall.

     Because the Ascender can be flared assertively at a much faster airspeed, it does not have to be slow down gradually while skimming along in ground effect.  Therefore, only a short distance is necessary to execute the landing.  Because less distance is required, the landing field may be much smaller.  This permits more clearings to serve as landing fields and additional hang gliding sites may be opened up.  Because a smaller area can suffice as an adequate place to land, flying cross-country becomes less risky.

     Because the Ascender has an extra-large wing with a lighter wing loading, it can fly slower before it begins to stall.  Because stall speed occurs at a slower airspeed, the glider can fly slower before it has to be flared.  The flair window is widened because the glider may be flared either sooner at a faster airspeed or later at a slower airspeed.  Because the Ascender may be flared safely over a wider range of airspeeds, the pilot requires less proficient to preform graceful stand up landings.  However when first learning to fly the Ascender, beginning pilots may use the control stick vibration caused by stooping-flight as an indicator when it is a good time to flair the glider.

     Pilots are seldom injured while in flight.  The greatest danger exists when coming back into contact with the Earth.  Therefore, the landing is one of the most consequential factors to consider when deciding if it is or is not safe to fly.  Because the Ascender has an extremely wide flare-window, it should be the safest glider to fly.  ACE reduces the usual design compromise between flight performance and landing ease.

Master Link

     The linkage system’s mainframe assembly and three wing segments complete the triadic wing.  The triadic wing, the control stick, control frame, cables, and some smaller parts complete the glider.  However, the linkage system is not complete unless the pilot is included.  This is because the pilot’s body serves as an essential interrelated component of the total linkage system.

     When the pilot pins her harness to the bottom end of the control stick, takes the prone position, and grips the base tube with both hands, she establishes a three-point connection with the glider.  This three-way linking up with the glider completes the three-way closed-loop circuitry of the overall linkage system.  Therefore, the pilot is literally the connecting master link that completes the three-way closed-loop circuity of the overall linkage system.

     The pilot applies forces to the glider by moving her hands in relation to her center of mass.  This relocates the pilot plus glider center of gravity and manipulates the wing segments.  The shape of the triadic wing is transformed by the manipulations that take place between the wing segments.  Changing the wing’s shape changes how the glider flies.  Hence, it is agreed that the wing segments function as an artificial extensions of the pilot’s body.  This strategy places the pilot in command and subjugates the glider to her position of dominance.

     Because the Ascender is mechanized by the linkage system and because the pilot is the connecting master link of that linkage system, it is understood that a direct physical interface exists between the pilot and the wing segments.  The wing segments are actuated by the pilot’s body and the pilot’s body is augmented by the wing segments.

     The pilot is interlinked with the dynamic interchange of forces that passes back and forth through the linkage system.  Hence, the pilot can feel the three-way interplay of forces that takes place between wing segments.  Because of the special principles associated with the ACE method of flight control, the pilot can feel the wing segments functioning as an appendage to her body.

     While flying, it feels to the pilot as though the left and right primary wings segments are connected to her respective left and right shoulders.  One reason for this is that the primary wings are located just above the pilot’s shoulders.  Another reason is that the pilot uses her arms and shoulder muscles to actuate movement of the primary wings.  While flying, it feels to the pilot as though the tail wing is connected to her center of mass.  One reason for this is that the tail wing is mechanically connected very close to her center of mass by way of the linkage system.  Another reason is that, how the pilot moves the primary wings in relation to her center of mass, determines how the tail wing has to move in relation to the primary wings.

Self-controlled Flight

     The pilot is in fact the master link of the linkage system.  However, she is not a requisite for the glider to be capable of flight.  The Ascender maintains flight stability regardless of having a mechanically flexible or articulated wing.  Fiberglass coil springs are used to apply an adjustable amount of preload-tension to the linkage system.  The preload-tension attempts to hold the wing segments in a specific related alignment.  This relative alignment forms the triadic wing’s default contour.  That default contour causes the glider to have a propensity to fly straight, level, and at its trim speed angle of attack.

     If the pilot does not intervene, when the glider is struck by a gust of wind, the linkage system’s springs absorbs some of the shock by permitting the wing segments to be deflected somewhat into alignment with the changing air current direction.  Then the linkage system’s preload-tension automatically returns the triadic wing back to its default contour.  This gives the glider the impetus to resume flying straight, level, and at its trim speed angel of attack.  In this manner, the linkage system tends to provide some autopilot-like yaw, roll, and pitch stability.

     At times, the pilot may choose to hold the base tube lightly with the tips of her index fingers and thumbs.  This permits the glider fly itself.  Allowing the glider to self-control helps the pilot to better sense how the wing segments are moving in relation to one another as they respond to the changes in air current direction.

     Because of the interactions that take place between the primary wings and the tail wing, the pilot feels how the vertical airflow or lift being entered compares with that just exited.  Because of the interactions that take place between the primary wings themselves, the pilot feels how the lift on one side of the glider compares with that on the opposite side of the glider.  Because the wing segments naturally align themselves with air current directional changes, they tend to trace out the dynamic shape of the air currents and thereby describe the invisible ambient atmosphere.  This enhanced awareness can help the pilot to better visualize the environment in which she is flying.  With some practice, pilots will learn to use this acquired knowledge to their advantage.

Flight of Fantasy

     According to the scientists, avian lifeforms evolved the ability to fly during the epoch of the dinosaurs.  This was long before we evolved into Homo sapiens.  For as long as our species have been looking up, there were birds to be seen soaring around overhead.  People have always watched the birds, envied their freedom, and wanted to imitate them.  The original experimenters of manned flight first envisioned birds as a model to go by.  Their attempts failed for two main reasons.  One reason was that they had yet to learn the underlying principles of flight.  Another reason was that they did not understand enough about how birds control their non-flapping flight.  Ironically, this information is now available on the internet.  It is free to those willing to do extensive research.

     Contemporary hang glider makers have perfected the sweptback planform and increased flight control with wing warping.  This increase in control has made the activity of hang gliding much safer.  Advancements in hang glider design have resulted in beautifully crafted works of art.  Modern kite designers really do know what they are doing and sincerely deserve our appreciation.  Even so, they continue to use weight shift as the principal method of flight control and they do not really attempt to exploit the aerodynamic controls demonstrated by nature’s natural flyers.

     Standard sweptback hang gliders are still somewhat like maned untethered kites.  The pilot dangles from a wing and swings her body about to direct the glider’s flightpath.  Even though greatly improved, this is the same process used by Otto Lilienthal.  Otto is often referred to as the pioneer of hang gliding.  He lost control of his glider, crashed, and died in eighteen ninety-six.

     Avian lifeforms can fly because they evolved the ability to do so.  Human can fly because they have evolved a superior intellect.  However, the flying abilities of soaring birds far surpass those of even the very best hang gliding pilots.  Therefore, it is sensible for intelligent people to use their creative intellect to figure out how to fly more like our fine feathered friends.

     Serious scientists sometimes conduct thought-experiments by imagining abstract scenarios.  They consider how things might be if they were somehow different from what they are assumed to be.  By pondering over what-if questions, they broaden their perspective and come up with original ideas.  Occasionally, this leads them to a deeper understanding of the real world.

     There are fundamental distinctions between the Ascender and all other types of hang gliders.  It is judicious to recognize that the Ascender is much more advanced than a manned untethered kite.  To differentiate between a conventional hang glider and the Ascender, the reader is now asked to embark upon a flight of fantasy by imagining something like a bad science fiction movie.

     Let us pretend that there is an alternate reality where a species of humanoid-like lifeforms evolved the ability to fly.  We shall call these bird-like primates bird-people.  Infant bird-people are born with little proto wings that develop as they grow older.  The fledglings start out learning to walk, run, and then to fly like their parents.  It is normal for the bird-people to fly because they grow natural wings that function as a part of their bodies.

     Now suppose that sadly some bird-people have a rare birth defect and are born without any wings.  These unfortunate individuals are disabled because they cannot fly like the others of their kind.  Because they are handicapped, it is logical to substitute their missing wings with prosthetic wings.  Artificial wings are not going to function as good as real wings.  Even so, if a synthetic substitute were engineered to respond to their body movements as though it were a set of real wings, it would become possible for them to preform gliding flight like the normal bird-people.

     The two previous paragraphs presented a thought-experiment.  The purpose was to instill an opened mindset and consider things from a different point of view.  This innovative perspective suggests that, when it comes to flying like real birds, human beings are inherently disabled because they cannot grow real wings.  Once we begin to think of ourselves as being handicapped, it becomes logical to devise a prosthetic wing.  An artificial wing is not going to function as good as the real wings of birds.  However, if an artificial substitute were engineered to respond to our body movements as though it were a set of real wings, it would become possible for humans to perform gliding flight somewhat similar to the true masters of flight.

     Prostheses are synthetic replacements for missing body parts.  Because people do not grow winged appendages in the first place, the Ascender cannot be correctly defined as a prosthesis.  Even so, the articulated wing segments of the Ascender’s triadic wing are in fact engineered to function as though they were an artificial substitute for missing natural wings.  That is because the pilot’s body maneuvers do manipulate the wing segments as though they were an appendage to her body.  This profound distinction raises the Ascender to a loftier category of hang glider.

     To fly with the supreme flying abilities personified by soaring birds demands the exploitation of their aerodynamic controls.  ACE technology comes much closer to accomplishing that than anything else in existence today.  ACE engenders biomimicry into the design of a hang glider and that differentiates the Ascender from all other types of gliders.  ACE can endow hang gliding pilots with the ability to fly more like the soaring birds that we cannot help but to admire.  ACE is going to make it practical for us to attain some of the remarkable capabilities exemplified by God’s own paragons of flight.

Safety

     It is probable that many hang gliding pilots are not going to accept the ACE concept at first.  This is as it should be.  That is because new ideas ought to be meet with skepticism until they have been proven by the exacting process of thorough testing.  This is especially true when the ultimate proof-of-concept will eventually be determined by no less than life or death consequences.

     When a hang gliding accident results in the demise of the pilot, it is typically due to a crash.  Most collisions occur when the pilot loses control of the glider or makes a mistake in how the glider is controlled.  There is an obvious and veritable correlation between flight control and flight safety.  Therefore, a substantial increase in flight control, with only a negligible loss in stability, should be beneficial in the endeavor to prevent needless injuries and the loss of human lives.

     There has been a prevalent theme throughout this discussion.  It is the assertion that the integration of weight shift with articulated aerodynamic control provides a more effectual technology for controlling the flight of a hang glider than with weight shift alone.  This is a true statement for a number of compelling reasons.

=================================================================================

     Dennis, it is understood that you will have some concerns about the ACE concept.  This is expected because there is much more information that needs to be revealed about the ACE method of flight control.  Please, feel free to state your opinion and ask questions.  It would be wonderful to hear from you.  Your help is sorely needed.  If this subject interests you, please reply by writing to the following address:

                                                                                                                       James Allen Rouse or (Jim)

                                                                                                                       330 S. Cedar Ave. Apt. 211

                                                                                                                       South Pittsburg, Tennessee

                                                                                                                                                         37380

                                                                                                                       With respect for your expertise,

                                                                                                                       _________________________

                                                                                                                       James A. Rouse