Hang gliding 1978 and 1979 part 2
This page follows Hang gliding 1978 and 1979 part 1.
The images on this page are mostly my artistic derivations of contemporary photos. See Copyright of early hang gliding photos.
A colour photo of Liz flying her Condor appears on the next page and there is an external link to an article about her farther down this page.
In 2012, long time instructor Ken De Russy sent me several American hang gliding magazines and books pre-dating my own collection. They provided much information I drew on for these pages.
The UP Mosquito was unique in its combination of forward-canted king post, triangular tip fins, and heavily bowed leading edges. A British pilot reported that the leading edge tubes were straight, but when launching in light wind, they took up their curved alignment part way through the launch run with an alarming clunk!
For a link to Richard Cobb’s comprehensive UP Mosquito page, see the related topics menu Ultralight Products of California and Utah.
The Mitchell Wing was, like the earlier Icarus 2 and 5 by Taras Kiceniuk Jr. and Volmer Jensen’s VJ-23 and VJ-24, a rigid hang glider that required a trailer to transport it. Like the Icarus 5, it was a tail-less monoplane in which aerodynamic stability is built into the wing, as is the case with most flex-wing (Rogallo) hang gliders. Unlike the Icarus 5, the Mitchell Wing was ‘cantilevered’; its structural strength was built inside the wing rather than relying on external struts and cables. Roll and yaw control were provided by tip rudders, much as with the Icarus rigids and the ‘semi rigid’ Fledgling, while pitch control was by pilot weight shift.
George Worthington, a former US Navy pilot, became a world distance record-holding hang glider pilot in his fifties and sixties flying a Mitchell Wing as well as flying flex-wing hang gliders in the Owens valley.
While sandbag testing of single surface gliders suspended upside-down is effective (refer to the related topics menu Testing for stability and structural strength) 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 Hiway upside-down test) force on the cross-tubes?
That was one impetus behind hang gliding associations in several countries creating structural and pitch stability test rigs. They included the Hang Glider Manufacturers Association in the USA, the DHV in Germany, and the British Hang Gliding Association.
I don’t know of anyone, inside or outside of the hang gliding industry, who is capable of doing an accurate structural analysis of a flex wing hang glider; the loading situations are far too complex and varied.
— Mike Meier of Wills Wing writing in Hang Gliding, June 1983, to explain why rigorous testing is required
See also the Hang glider sail painting related topics menu.
George Worthington was a retired navy pilot who held world distance records in both rigid and flex-wing hang gliders. Tom Peghiny started designing and building his own hang gliders while still at school. Dennis Pagen writes the most authoritative texts about every aspect of hang gliding.
Dennis Pagen, a prolific author of hang gliding technical articles and books, was U.S. champion in 1978 flying a Sky Sports Sirocco II, which he partly designed. For more about this east coast manufacturer, see my page Flying squad.
Fly straight with perfection
Find me a new direction
— From the lyrics of The Raven by the Stranglers, 1979
A manufacturer in the USA discovered by accident that their novice level glider without deflexor wires bracing the leading edges outperformed their more advanced wings. (I am not sure whether Electra Flyer of New Mexico or Wills Wing of California was first with that discovery.) Realizing that deflexors caused too much drag, hang glider manufacturers then changed to stronger leading edge tubes instead. Wills Wing, just one of the several hang glider manufacturers based in California, replaced their three production hang glider types, the Omega, Omni, and Alpha, by a single defelexorless design; the Raven. (See the related topics menu Sport Kites/Wills Wing of California.)
Notice the absence of deflexors along the leading edges, with their cables, adjusters, supporting struts, and attachment fittings. All gone! Even the outer ends of the crosstubes and their attachments to the leading edges are tucked away into the slower moving air close to the underside of the sail.
Erik Fair, shown here demonstrating correct landing flare technique in a Wills Wing Raven, wrote an entertaining and instructive book titled Right Stuff for Hang Glider Pilots.
In this image the creases in the left (underside) leading edge pocket, caused by differential span-wise tension between the leading and trailing edges, create an incorrect impression of the camber of the sail, incidentally. The orientation of the batten pockets provides an accurate indication.
This topic continues in Hang gliding 1978 and 1979 part 3.
3 Decades of Liz by Liz Sharp as told to C.J. Sturtevant in Hang Gliding & Paragliding, May 2008