A short history of the east coast U.S. hang glider manufacturer Sky Sports, by Everard Cunion, June 2016, including photos and info from Chris Gonzales
“He’s got the church and the palace of Westminster on his side. Who have you got?”
“My mum. She thinks I’m a genius.”
— from a dialog in The Sweeney, a popular 1970s television series about a fictionalised UK Metropolitan Police ‘flying squad’
Looking for a new England
Sky Sports was a hang glider manufacturer based in Connecticut, New England (according to their magazine advert in August, 1977) north of New York. (Do not confuse the east coast manufacturer Sky Sports with the similar sounding Sport Kites of California; later renamed Wills Wing.) The flying there is arguably more demanding than in California, where most hang glider manufacturers were based, because of the wind and rain. A bit like where I live in old England, by the sound of it. However, unlike old England, the flying regions of New England are largely tree-covered, with ‘tree slot’ launches and tight landing areas.
While some trained aeronautical engineers made great contributions to early hang glider development, on the whole they did not build better hang gliders than those who were self taught (whose mums doubtless thought they were geniuses). As far as I know, Sky Sports originally relied on designs by hang gliding pioneer Tom Peghiny, whose early work included a ‘cylindrical’ Rogallo wing with highly curved leading edges. His later work included a monoplane with a V-tail, which was nevertheless weight-shift controlled, like conventional Rogallo wings.
Eventually, Peghiny was joined by another self-taught hang glider designer, Terry Sweeney, an electronics technician (self taught in that too) working in the field of radar jamming electronics for the military. Together, they created the Sirocco, one of the first double-surface flex-wing hang gliders. (That info comes from an interview with Terry Sweeney by Bill Allen, published in Hang Gliding, August 1977.)
Notice the shape of the sail of the Sirocco in the accompanying screenshot from the Francis Freedland documentary film 1978 Pico Peak International Hang Gliding Meet (see my review). The inboard battens were secured in position with cables to the control frame corners and (apparently) to the top of the king post. The sail was thereby kept from applying upward (or in the event of severe misfortune, downward) force on the crosstubes. (Nowadays they build the crosstubes strong enough to take any additional bending forces imparted by the sail.) Those wires arguably also improved the span-wise twist distribution of the wing.
Incidentally, the pilot in the screenshot is flying in a seat harness inside the control frame.
This Sirocco 1 originally belonged to Chris Gonzales’ instructor, Mike McCarron.
Double surface wings enclose the cross-tubes between the upper and lower surfaces of the sail, which eliminates the aerodynamic drag of the crosstubes. This photo also shows deflexor cables cluttering the leading edges. They added strength and kept the lanky tubes from distorting out of shape. However, those deflexors also created a lot of drag, increased the cost of manufacture, and increased the time you spent rigging and de-rigging your wing. Modern hang gliders do not have them.
Sweeney worried about the lack of pitch stability of the standard Rogallo in a dive, as many of us did. At zero angle of attack, the sail ‘luffed’ (flapped uselessly) and created no lift to shift your weight relative to, so you were unable to pull out of the dive. Given enough height, the drag of the flapping sail would — in theory — pull you out, but we rarely gained enough height for that in those days. In 1973, Sweeney added a strut under the sail near each wingtip, with a cable to the top of the king post that limited the strut’s downward arc about its attachment to the leading edge. In an extreme dive, it acted as an up-elevator. It was a combined dive strut and reflex bridle, as we would understand it today.
Bear in mind that the personal computer was still years away. Unless you had links with academia, in which case you might obtain time on a mainframe computer, you either used a slide rule to aid hand-written calculations or you used a programmable calculator to help design your wings. If you were a bit outside the box, you used a Hewlett Packard reverse Polish notation calculator, which did not even have an equals = key!
Sweeney’s hang glider design program, which he used on the Sirocco project, contained 224 steps. However… “We still sort of handle the shapes intuitively — the nose angles and the sweeps, and the anhedral/dihedral tuning, and stuff.” (From the interview by Bill Allen in Hang Gliding, August 1977.)
The Sirocco II, which (according to those who know) was Sweeney’s own project with input from Sky Sports test pilots, had six battens per side, as compared with the original Sirocco’s five per side. The Sirocco II also had a wider nose angle and more area at the tips. Chris Gonzales describes it as a “great design.”
Related (internal links)
Mid-day lightning in Vermont, my review of the Francis Freedland documentary film 1978 Pico Peak International Hang Gliding Meet
Vtg Goth Lolita, my review of the Stanley Kubrick movie Lolita, set in New England, but largely filmed in olde England
Skyhook Sailwings, a short history of the early hang glider manufacturer based in the north of England
See also (external link)
For a remarkable photo of the Sky Sports Sirocco, see this Oz Report forum post. On a Windows computer, right-click the partial image and select Open image in new tab or View image (or your browser’s equivalent) from the shortcut menu.