Tech Talk - Rogallo Wing & More
November/December 1963 American Modeler
Most people probably think of the familiar triangular Rogallo Wing as a platform for hang gliders, but its original intention was as a recovery system for manned space vehicles returning from orbit. In fact, Francis M. Rogallo won a $35,000 prize from NASA in 1963 for the invention. It had been seriously considered for the Gemini rocket program. Parachutes won out in the end, and were the primary form of recovery for the entire manned space program up until the Space Shuttle fleet was commissioned. In an utterly sickening turn of fate and irony, America's astronauts now hitch rides on Communist Russia and China spacecraft which return to Earth on parachutes. NASA's urgent mission now is, according to its administrator (Charles Bolden), is to establish an outreach to a foreign religious group.|
Scientific Side of Modeling
By Bill Effinger
Coupe 'd Hiver event grows popular. This is a new challenge for the oldtimers and a real break for the newcomers in outdoor rubber. The Frenchmen started it, so the name stands, meaning "Winter Cup." Pronounced coop-d-veer and originally intended for Winter Flying in small fields, the category is finding eager followers among both beginners and experts. Maybe it's because the rules are simple: Motor limited to .35 ounces; model, less motor must weigh 2 1/4-oz minimum; must ROG (no VTO possible with small motor but most models can "hop-off" without wheels); minimum fuselage cross section is 3.1 sq. inches.
Over their heads, a $35,000 "kite"! Francis M. Rogallo and his wife, Gertrude, are $35,000 richer due to the invention which they hold. It is a "Rogallo Wing" model; the design led to the development of paragliders which can be packaged and deployed. National Aeronautics and Space Administration made award, largest NASA has ever given to inventors. Device is being considered for main recovery system in phases of Gemini earth-orbit space program.
With such rules nobody to date has made a "max" flight ... thus the challenge. Only one thing I don't like is that there is no limitation on wing area. The New England Wakefield Group is largely responsible for the popularity of the event in this country. Many existing models fit the event.
For the Yankee Championships Hank Struck couldn't quite finish his special job so he resurrected his 23 year-old Interstate Cadet Scale National's Winner and managed to place seventh with it by just reducing the amount of rubber motor. But I asked Hank for a sketch of his "Boom Daze" which is shown here. Every club should start their newcomers in rubber with this event before trying the bigger Wakefield jobs.
Airfoil Testing. Last issue I promised to give results of tests for symmetrical airfoils. Sorry to advise that although all the sample panels and planes are ready, we just couldn't complete the experiments in time for this issue.
Mail Bag. Letters have been coming in showing that there is terrific interest in airfoils and basic aerodynamics. Future columns will concentrate more on this segment of modeling. Howard McEntee gave my home address in his column and letters and phone calls started coming direct rather than through the magazine's editorial offices. It shows how carefully everybody reads Howard's articles! I am in the process of moving, my address when this goes to print will be Ramblewood Drive, Branford, Conn. So you can send your questions direct to me if you wish.
Boom Daze Plans
New Record Sparks Memories. Announcement of a 13,320-ft FAI R/C Altitude Record by Maynard Hill of Washington, D.C., brings back memories of the attempt I made back in 1950. This latest mark was made by R/C models followed by radar which was synchronized with optical tracking. The radar picked up blips off Mylar towed as a ten-foot streamer on the model's tail.
My earlier attempt was for a free-flight record - R/C was not permitted then. We built "Super Brigadiers" with extra wing area for the attempt. Models had extra large fuel tanks, good for about 30 minutes engine run. With the Navy's permission, we were able to ground test the engines at the Bethesda, Md., Medical Center in a decompression chamber. The tests were interesting since we went up to a simulated altitude of 20,000 feet in the chamber; an Ohlsson "33" engine was run during the check. Power fell off due to the lower air density with the fuel mixture enrichening at the same time. However, there appeared to be plenty of power for flying the model at 20,000 ft.
In the chamber we had difficulty taking notes at this altitude, but the real pay-off was when we came back to sea level conditions too quickly. We were all slightly intoxicated for about two hours and couldn't walk a straight line. Somewhat embarrassing to say the least!
Dallas, Texas, was chosen for the test trial. We were told that we could expect the cloud layer to form there at 22,000 feet. When we got there, the local "Weather Guesser" laughed at the tall Texas story we had been told. Actually the layer forms at 7,000 to 9,000 feet. Getting though this disturbed air, even if no clouds appear, is the hardest part of an altitude attempt. We just couldn't make it.
In those days the model had to be tracked by an instrumented full-scale airplane flying at all times below the model. Just picking up a sight on a model from a full scale airplane is tough enough. We sent up weather balloons at the same time as the model so we could follow the drift but on three out of four flights we just couldn't follow the model. The instruments were in a Grumman TBF which couldn't turn sharply enough.
Now, with radar permitted, I look to see the record broken soon again. If you want to try, pick a location with high cloud formation. I suggest spark ignition rather than glow plugs for high altitude since g.p. power falls off faster with glow than spark ignition. Spark also has the advantage of being able to bum gasoline; its consumption is considerably lower that glow fuel.
(By the way, have any readers tried transistorized spark ignition yet?)
Posted July 6, 2013