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By USHPA7
#406271
Yeah Red, if I had made it a flex wing I would have had a "modern" hang glider in 1971. I had very little money to build it so that determined what materiales I used. The LE's were rain for rent irrigation tubing (suggested by Roy Haggard). Roy later went on to design the Dragonfly flex wing, which he said my design had inspired.

Back then everybody was saying that nobody would want to fly a 75 lb hang glider (that was the estimated weight of my Skysail). Ha - time proved them wrong.

Frank.








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By TjW
#406303
USHPA7 wrote:
Sun Jan 20, 2019 11:02 am
Back then everybody was saying that nobody would want to fly a 75 lb hang glider (that was the estimated weight of my Skysail). Ha - time proved them wrong.

Frank.
Later on, I took grief for have to stuff six battens per side on my Fledge.
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By red
#406309
TjW wrote:
Tue Jan 22, 2019 9:41 pm
USHPA7 wrote:
Sun Jan 20, 2019 11:02 am
Back then everybody was saying that nobody would want to fly a 75 lb hang glider (that was the estimated weight of my Skysail). Ha - time proved them wrong.
Frank.
Later on, I took grief for have to stuff six battens per side on my Fledge.
TjW,

Same here, from the same pilots who now stuff 21 ribs into their glider, without a second thought. :lol:
#406310
<< "Later on, I took grief for have to stuff six battens per side on my Fledge".>>

I think the simplicity and lightness of the "standard" Rogallo tended to delay progress on more complicated but better flying and safer gliders.

While I was struggling learning to fly my 75 lb Skysail, which had to be transported in two halves, in a trailer and took a lot of assembly time, my teenage son Matt was flying his 30 lb Eipper 17' Rogallo off mountains all over SoCal. He often went with the Bob Wills group to fly new sites.

Frank
#406317
USHPA7 wrote:
Wed Jan 23, 2019 1:23 am
I think the simplicity and lightness of the "standard" Rogallo tended to delay progress on more complicated but better flying and safer gliders.
That may be true, but it also created a larger market to accommodate those pilots who eventually wanted "more complicated but better flying and safer gliders."

That's often the way technology proceeds, by making inferior products that many, many people bought, thereby creating a demand for superior products. I don't think Apple would have created the iPod without Sony's already having released the Walkman, proving that there was a market for portable music devices. Who uses a Walkman anymore? Who even owns one?

Similarly, those of us who have been around computers may still remember using cassette tapes to store programs and data. They made it possible for the home computer user to store their stuff, and without them the home computer would have stayed a hobbyist's plaything rather than a useful tool. Although the cassettes did the job, they were in many ways a major PITA. When the floppy disk came along, people abandoned the cassette format, only to abandon the floppy disk when thumb drives came along. But if those first computers had no method at all for conveniently storing data, the personal computer industry would have been dead in the water, with no market for floppies or thumb drives.

At least, that's my take on it.
#406320
Yes.

That is why I designed and I am building the "Hang Gliding Basic Trainer", Puffin. To get that entry level glider back in the hands of beginners. Sure it's not as simple as the Rogallo ( 10 battens to slide in) but hopefully will be as easy to handle and fly better and then the student moves on to better performing gliders.

My premise: many aircraft pilots learned to fly in a lower aspect ratio, easy handling, slower flying airplane, than they currently fly. Why not HG pilots?

New flip phones are again available (I use one).

Frank
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By mario
#406327
Frank, your new trainer glider reminds me of the glider Paul MacCready was designing and making when I first started hanging out with his family in 1974. I was just 11 years old and they were working on what Paul called the “MacCready Safety Glider”. It was basically a Rogallo wing that had the crossbar extending out to the tips to create truncated tips and it had shaped ribs along the wing. His youngest son was the test pilot on the dune and he discovered on the first flight that the stiff wing had reverse roll control and crashed it. Luckily he wasn’t hurt too badly and they scrappped the glider. That wing fortunately became the source for my sailing canoe with jib (which worked great) and unfortunately ended young Marshall’s desire to ever fly again. We went on to designing many wings after that, and made our models with control frames and movable dangling weights to simulate a pilot’s input. Making those models with my brothers and the MacCreadys, going to the dunes to ground skim all day, watching poeple like Volmer Jensen, Taras, Chris Wills and many others fly, and seeing people like you and other designers coming out with a new design every week were the best years of my life.
Here’s an article you may remember: https://www.nytimes.com/1973/09/01/arch ... t-sky.html
It kinda predicts paragliders in the end of the article.
Good luck with your project!
Mario Miralles
#406330
Thanks Mario.

I had not seen that article. It brought back a lot of memories. Kind of sad to realize that the popularity of the new sport didn't grow like we thought it would. Now we only have two manufactures left in the US. :( And hang gliding is illegal anywhere in the city of Torrance. I remember people sitting out on their patios of the houses on the cliff top enjoying watching the gliders float past. I'm glad that, thanks to Joe Greblo, we still have Dockweiler Beach even though it doesn't have the high cliff of Torrance Beach.

I was not aware of the MacCready safety glider experiment. I wonder how similar to mine it was?

My Puffin's keel pocket and floating cross spar may cure the adverse yaw problem he had with his design.

I always enjoyed talking with Paul every chance I got. One time he brought me his son's Colver vario to repair because it had been in the salt water off Point Fermin when his son landed in the surf.

Frank
#406334
mario wrote:
Thu Jan 24, 2019 1:00 am
It was basically a Rogallo wing that had the crossbar extending out to the tips to create truncated tips

That rang a bell for me. Back in the 70s, Chandelle came out with the "Competition" glider, and one of its design features was a crossbar that attached toward the aft end of the leading edges. I think the idea was to reduce deflection at the rear of the spar. At any rate, the glider quickly earned a reputation for "adverse flight characteristics" and was at least part of the company's ultimate demise. Maybe there's somebody on the board who can give more details than this.

I remember having a Chandelle Comp come into my shop in Maryland, where we "de-Comped" it, shortening the crossbar and fitting it at a more conventional point along the leading edge ... converting it, in essence, back to the "standard Rogallo" configuration. Although it flew well enough after the conversion, the owner still wasn't happy with it and ended up buying a Cirrus 3 from us.
By USHPA7
#406335
The dangerous aspect of the Comp was lack of reflex. Once the nose went down to a critical low angle it would go into a divergent, non-recoverable dive. The lack of stabilizing reflex gave the glider a better glide than other rogallos.

My son Matt, witnessed a death at Box Springs Mountain in SoCal. The Comp pilot said to anyone standing nearby: "Here I go in my "killer Comp"" just as he started his launch run. People had started calling the glider that name by then and he was mocking them (reminds me of the attitude toward PG's near the ground collapse nowadays).

Away from the mountain he went into the dive and I don't know what caused the nose to drop in the first place, possibly turbulence, but the dive became divergent and he went straight in.

Matt quit flying hang gliders then, after being on the scene of the accident.

Frank C.
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By TjW
#406336
jlatorre wrote:
Thu Jan 24, 2019 12:20 pm
mario wrote:
Thu Jan 24, 2019 1:00 am
It was basically a Rogallo wing that had the crossbar extending out to the tips to create truncated tips

That rang a bell for me. Back in the 70s, Chandelle came out with the "Competition" glider, and one of its design features was a crossbar that attached toward the aft end of the leading edges. I think the idea was to reduce deflection at the rear of the spar. At any rate, the glider quickly earned a reputation for "adverse flight characteristics" and was at least part of the company's ultimate demise. Maybe there's somebody on the board who can give more details than this.
As I understood it, there was a pitch stability issue. Under load, the forward/inboard part of the leading edge bowed in, and the outboard/rear part flexed out, giving more camber in the front and less washout.
A couple of them dove in. Whether this was specific to the Comp, or just the same luffing dive problem that all standards had would be hard for me to say.
I always thought the folding crossbar was cool. It made for a remarkably quick setup if you left the control bar set up, as was the style at the time. Pull up the kingpost and fasten the wire, spread the leading edges and fasten the the center of the crossbar with, I think, a pip pin.
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By red
#406339
jlatorre wrote:
Thu Jan 24, 2019 12:20 pm
mario wrote:
Thu Jan 24, 2019 1:00 am
It was basically a Rogallo wing that had the crossbar extending out to the tips to create truncated tips
That rang a bell for me. Back in the 70s, Chandelle came out with the "Competition" glider, and one of its design features was a crossbar that attached toward the aft end of the leading edges. I think the idea was to reduce deflection at the rear of the spar. At any rate, the glider quickly earned a reputation for "adverse flight characteristics" and was at least part of the company's ultimate demise. Maybe there's somebody on the board who can give more details than this.
Campers,

I remember the Chandelle Comp glider. What follows is all to the best of my memory, and the teachings of pilots I trusted . . . The leading edges were 18,' and the crossbars attached at 15' from the nose. Those skinny leading edges would flex upward in slow flight, creating a Cylindrical sail. (In theory, the glider would "fit" in flight on two large parallel cylinders, that had some overlap between the cylinders.) The Cylindrical variant of the Rogallo wing did fly better, but did not handle very well. It did also fly slower than a Standard Rogallo. That much is the good news.

The bad news was that if the Chandelle Comp glider ever stalled or went weightless, the leading edges became straight again. The glider then became a fully stalled Standard Rogallo, and the nose dropped into a dive. Now there was little or no lift (so, no Cylindrical, and no airfoil shape to the sail), but only drag. With the drag on the sail, the leading edges then bowed inward at the nose, not upward, which caused the wingtips to pivot outward. That pivot action pulled the trailing edge down flatter, creating a "down elevator" all across the wingspan. That "down elevator" caused the glider to dive steeper, faster, and steeper, until stopped by the ground. Weight shift by the pilot would have no effect on the dive. Luff lines (which were almost completely unknown, and not in common use then) might have caused the glider to recover from the dive. A modern HG parachute (which did not exist then, either) would have saved the day, if the glider was high enough to use one. We seldom flew high enough to use a parachute, in those days.

It was not long after that time when the Pitch-Testing truck was developed, and now all HGs are REQUIRED to pass the truck testing.

NONE of these problems would apply to Frank's new Puffin design, because the Puffin will have large and strong leading edge tubes, fixed ribs (so the airfoil can NOT collapse in a stall), and (ANTI-) luff lines, so the trailing edge can NOT get pulled downward even if the frame flexed at all.

We did pay a high price for the aerodynamics lessons 'way back when, but we have learned.

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