Hang gliding 1977
This page follows Hang gliding 1976 part 2.
The images on this page are artistic derivations of contemporary photos. See Copyright of early hang gliding photos.
On June 24th, 1977, Bob Wills of Wills Wing was killed when his hang glider was struck by the down-wash of a helicopter filming him for a Jeep advert. Rob Kells, Steve Pearson, and Mike and Linda Meier took on the development of Bob’s latest design, and Wills Wing continued as one of about sixteen major hang glider manufactures in the USA. (1)
Wills Wing re-used the name Cross Country for their popular 1995 wing.
See the related topics menu Sport Kites/Wills Wing of California.
If you let a hang glider catch the wind at the wrong angle and you do not correct it quickly enough, nothing can stop it turning over and taking you with it. (Been there, done that, got the t-shirt…)
See the related topics menu Seagull Aircraft of Santa Monica, California.
The damage in this incident was limited to the power line and the glider.
Jim and Henry Braddock were second and first, respectively, at the U.S. national championships held at Heavener, Oklahoma, in July 1977. (Heavener rhymes with heathen, not heaven, apparently.)
Powered hang gliding was going through its early stages at this time. (See Early powered ultralights.) It brought problems additional to those inherent in hang gliding. The man standing and speaking in the following picture is hang gliding photographer and columnist Bill Allen.
The original photo by Jim Theis, on which this artistic rendering is based, is of Dan O’Neil dune-soaring an Electra Flyer Cirrus 3 in a gale on the dunes at at Boca Raton, Florida, during tropical depression Anita in August 1977.
Grouse Mountain, where Leroy Grannis took the photo on which this image is based, overlooks the city of Vancouver, Canada. For more of Grouse Mountain, see Grouse Mountain invitational 1984.
Hang gliding was still regarded as a spectator sport in the late 1970s. Here is a snippet about pilots John Davis and Glenn Hockett and competition promoter Don Whitmore:
Davis and Hockett and Whitmore were interviewed for national TV, and the remaining pilots packed their gear in the warm late afternoon sunlight. The city of Vancouver was shining, the ships in the bay swinging into the seabreeze.
— W.A. ‘Pork’ Roecker writing in Hang Gliding, September 1979
Former actress Bettina Gray traveled the world to photograph hang gliders and this shot of the Skyhook Sunspot shows the shape of the sail in flight. See Skyhook Sailwings.
Immediately after launching on his first flight in the Sunspot, this author entered a series of rolls, to the left, then to the right, then left, right, and so on, until after maybe 20 seconds his nervous system caught up with the new glider’s combination of roll inertia (more that I was used to) and damping (less) that caused a subtle delay in its roll and yaw response. This Sunspot swing was common on such first flights, I learned later. Indeed, such pilot-induced oscillation (PIO) affects many pilots regardless of ability. One of the most skilled pilots ever, the astronaut Mark Stucky, suffered from pilot-induced oscillation in 1977 when he returned to hang gliding after 15 months away:
I was heading home after another PIO-filled weekend, trying my best to visualize just what the glider was doing and what the proper response should be. I somehow figured it out and surprised everybody when the next flight went smoothly.
— Lt. Col. Mark Stucky USMC (call sign Forger) in Hang In There Part Deux, Inadvertent Cloud Flying in Hang Gliding & Paragliding, February 2008 (linked later on this page)
Seth B. Anderson, chief of NASA Ames Research Center and hang gliding monitor at Yosemite National Park, presented a paper about hang gliding at the American Institute of Aeronautics and Astronautics Flight Dynamics Conference, 1994.(2) In 1991, Anderson entered a severe pilot-induced oscillation (PIO) on final approach to a landing in the Yosemite valley:
Observers on the ground stated that bank angles were approaching 45° about 50 feet above ground level (AGL). As I was slipping downward in a left bank, I recognized that a PIO had developed and I knew that an uncontrolled, serious-injury ground impact was only seconds away.
— Seth B. Anderson writing in Hang Gliding, September 1995
Anderson ‘released his grip’ on the control bar (not completely, I assume), the glider pitched nose-up, and ‘immediately the roll oscillation terminated.’ He landed only 10 feet in front of tall pine trees.
PIO is bad enough, but some later hang gliders required no out-of-synch pilot input to enter the so-called Dutch roll. (If you ever saw the opening sequences of the 1970s television series The Six Million Dollar Man, you have seen a crash caused by Dutch roll.) Hang glider pilot and NASA test pilot Mark ‘Forger’ Stucky determined that a high-performance hang glider of 1989 exhibited Dutch roll rather than being merely susceptible to pilot-induced oscillation (like the Skyhook Sunspot). See his article in Hang Gliding & Paragliding, February 2009 (also linked later on this page).
There might be a genetic element determining a pilot’s susceptibility to PIO in the ‘wiring’ of the brain.
Re PIO, my HP AT 158 seemed pretty well behaved until I rocked up out of prone and did tight S-turns. At that point I could feel the she wanted to oscillate in yaw – like her moment of inertia was just going to swing her around a bit more than expected. It did not feel coupled to roll in any significant way and was fairly easy to sort out. I generally loved how she handled, probably my favorite overall glider. Kudos to Mr. Pearson.
— Long time hang glider pilot Chris Gonzales (referring to Wills Wing designer Steve Pearson) (3)
The wing that Ash is flying in this picture is a Birdman Moonraker. See also Birdman and Solar Wings of Wiltshire, England.
The Hiway Scorpion sported a ventral fin. See the related topics menu Hiway of Sussex, England, and Abergavenny, Wales. Eventually this site was lost to pressure by local residents.
Aspect ratio, or span divided by average chord, measures the spindliness of the glider. More span provides greater efficiency, in principle. In practice, however, increasing span incurs problems in controlling the washout (span-wise twist) of the sail and it also imposes higher structural loads and it can incur handling problems.
In 1977, Electra Flyer added the state-of-the-art Olympus to their successful Cirrus series of wings. See the related topics menu Electra Flyer of Albuquerque, New Mexico.
The Gryphon 2, while retaining the bowsprit configuration with thick cables holding the wings spread (instead of cross-tubes) did away with the large under-surface of the first Gryphons.
Why was the extent of the under-surface reduced? I never flew one or discussed it with Miles Handley, so this is only speculative, but two reasons strike me as likely:
- First, the under-surface had no battens and, therefore, its camber could change both with angle of attack and — more crucially — with airspeed. I make the same point regarding the Markowski Eagle III: See under Technical in Scientific American hang glider for details.
- In addition, reducing the amount of double surface moves the point of maximum camber forward, which in flex-wing hang gliders generally (starting with the Mouette Atlas of 1979) was found to improve pitch handling greatly.
In addition, the tip rudders of the mark 1 were replaced with a wing warping mechanism. The latter connected the hang strap, via a pivoting tube attached to the rear of the keel, then connected via cables, to the leading edges.
See the Miles Wings Gulp and Gryphon related topics menu.
At first we had hoped to conduct strength tests using a car-top aerodynamic loading system, but we were warned by the experience of UP and Albatross in America that any test done in this manner tends to result in a large pile of scrap after the smallest fault develops in the glider. We therefore opted to test the strength of the glider by a static loading method (as is used for conventional aircraft).
— Steve Hunt of Hiway Hang Gliders writing in the BHGA magazine Wings, September 1977
Rigid wings such as the Easy Riser biplane were static-load tested too.
As the airframe and sail distort, in a flex-wing at least, the washout distribution changes, which guides you in where to place the next sandbag. According to Hiway Hang Gliders, the crosstubes of the glider were first to fail, by Euler buckling.
Notice in the Albatross test that the control frame down-tubes, which are normally straight, are bending under compression. Straight edges in the background are straight, so the curvature is not merely a photographic effect.
While sandbag testing of single surface gliders suspended upside-down is effective, there is a particular problem with sandbag testing of double surface sails: You cannot reach the underside of the upper surface to put sandbags on it. Even if you could — and even if there was enough room — how many sandbags should you place on the lower surface to add an ‘upward’ (downward in the upside-down test) force on the cross-tubes?
That was one impetus behind hang gliding associations in several countries creating structural test rigs subsequently.
This topic continues in Hang gliding 1978 and 1979 part 1.
Ashley Doubtfire, legendary hang gliding instructor, on British Hang Gliding History
Dutch roll: Hang in There, Getting My Way in Hang Gliding & Paragliding Vol39/Iss02 Feb 2009 by Mark Stucky, including Dutch roll in a Wills Wing HP AT 145
George Worthington Launching in the Owens Valley, 1977ish: Digitized film only 25 seconds long on YouTube. George was a retired U.S. Navy pilot and hang gliding world record setter in both rigid- and flex-wings.
HALF DOME! (1977) on skydiver and photographer Randy Forbes’ vimeo channel. Rich Piccirilli, Jim Hanbury, and Brian Johnson, together with film maker Carl Boenish and Wills Wing insider Chris Price, carry out a raid at Yosemite National Park, the details of which are narrated by text embedded in the video at the end…
It took two days traveling at night to get to the summit. Carl had so much camera gear that he had to hire two mules to bring him to the base of the ladder, which was 400 feet, straight up to the top. We hiked in the moonlight by waterfalls and raccoons. The next day while sleeping, our camp was attacked by an albino bear with pink eyes! He slashed a hole in our hanging food bag…
PIO: Hang In There Part Deux, Inadvertent Cloud Flying in Hang Gliding & Paragliding Vol38/Iss02 Feb 2008 by Mark Stucky, including PIO in hang gliders
1. Mike Meier, Wills Wing–The Early Years in Sky Adventures, Legends and stories About the Early Days of Hang Gliding and Paragliding edited by Jim (Sky Dog) Palmieri and Maggie Palmieri, 1998
2. Flight Characteristics of Modern High-Performance Hang Gliders by Seth B. Anderson, Hang Gliding magazine, September 1995
3. Chris Gonzales comment about PIO in Hang gliding late 1970s and early 1980s on Brave Guys and Beautiful Dolls