Early Development

The Rogallo Wing and Early Development
Francis Rogallo had invented his 'Rogallo Wing' in 1945 and worked privately on the design for the next 13 years. As part of the Space Race in the late 1950s, the design was brought into USA government agencies and further developed to investigate its value in delivering capsules back to earth with much greater precision than the existing round designs.
There is some fascinating information about the project here
http://amyshirateitel.com/2011/05/22/losing-rogallo-from-gemini/

Also there is some of the test footage and research reports on YouTube as follows –









As you will be aware the space program did not utilise the Rogallo wing for capsule recovery, but the knowledge gained from this research was utilised by the parachute industry to develop flexible wings to deliver both skydivers and military personnel and payloads with greater precision. It is certain that without this development the sport of parachuting would have been a lot slower in developing gliding canopies, if at all.
Pioneer and Irvin, amongst others, both developed designs and Irvin introduced several in the sport of parachuting.

The Rogallo Wing was and still is commonly used on hang-gliders and kites.

NASA wind tunnel tests on capsule and canopy models
Payload Tests

Pioneer test designs
Cutting from skydiving press mid 1960s
Irvin design
Irvin’s Eagle model morphed into the Delta II Parawing as the first commercially available parawing.

Irvin Eagle


Multi-coloured rigging lines to assist with the packing sequence.










The Delta II Parawing had a unique reefing system known as an “Opening Shock Inhibitor” as well as multi-coloured rigging lines which helped the packing sequence.


The OSI was intended to retard the opening forces during inflation. A similar function to a modern day slider, but designed long before the slider had ever been thought of. Steve Snyder helped develop the OSI and ultimately also contributed to the development of the ram-air slider. It consisted of a long and heavy duty cotton strap which was rolled around groups of lines during packing. The sequence of lines was critical hence the colour coding of the lines to help this process. The OSI was locked shut with a Velcro tab which was attached to the OSI “rip line”, which itself was attached to the front or “nose” of the canopy. The idea was that on inflation the nose of the canopy released the Velcro tab on the OSI and the wrap could unfurl as the canopy inflated and expanded.

Opening Shock Inhibitor (OSI) during packing
"OSI around lines, note the white rip line which releases the OSI on canopy inflation"

4 comments:

Randy Barnes said...

I owned the first Delta II Parawing sold in Texas (red & white checkerboard design)purchased from McElfish Parachute Service in Dallas. It was a real adventure to jump. Made my 1st through 5th at Seagoville, TX. 1st was great, gentle opening, flew beautifully, made the peas, Nice. 2nd jump, slow opening, otherwise OK. 3rd jump a total streamer and cutaway. 4th, incredibly hard opening. Saw stars, ya ha! 5th (a week later) malfunction..cutaway. This is getting old. 6th and 7th another week later. Hard openings, really knocked the snot out of me. Kept reviewing packing..all seemed by the book. Jump # 8 through 11, smooth openings, alls well. Maybe I've got this thing down. Jump 12, hard opening, two burned panels. Two weeks later Jump 13, partial malfunction, spinning, another cutaway. End of story. Sold canopy to soldier at Ft. Hood. Bought new PC and started having fun again.
Randy Barnes
Rockport, TX

craig said...

You either love or hate these canopies, I must say it has quite a reputation and not a good one at that. Thanks for your post much appreciated.

Anonymous said...

My Delta II (serial Number 431) was well made, thick no stretch lines that are color coded. The Deployment bag was well made from some square footage of canvas pacing mat and my best guess of what the bridle should be, compared to the size of the canopy. The lower lines were designed to open in groups of three: one release with every untwist of the Opening Shock Inhibitor (Synder's wraP)
One large or two small pilot chutes did the air anchor duties, as the jumper fell several feet away.

JC Smith said...

I had one of the first Delta IIs in Oklahoma back in the late '60s. The openings were a bit squirrely. We used to refer to the openings as "one humpers, and two humpers." Once we shortened the OSI and modified the packing a little the openings got a lot more consistent. There were three of us who all got them at about the same time. Paul Kiewit (C-5974) was the first. He didn't tell anyone about it and when he jumped it we all thought he had a line-over malfunction when we saw his opening. Shortly after that R.L. "Bob" Sellman (C-5261) and I got ours at about the same time and we both made the same mistake when we assembled them. We both ended up flying backwards on our first Delta II jumps. Mine even made the cover of "The Static Line" (The Oklahoma Parachute Association "magazine" put out by J. Walter Hickerson). The three of us were all members of the Oklahoma University Skydivers. None of the three of us ever had a malfunction on a Delta II but the openings were wild enough that a fourth club member used to jump with two reserves (a piggyback and a chest mount) when he started jumping his. Sadly, Bob passed away quite some time ago and Paul did also earlier this year. Blue skies my friends. JC Smith (D-2797)