Norman’s Klingberg Wing
The temperature in Amherst, New Hampshire, is about 20 degrees cooler than it is in San Jose as I open an email from our East Coast Correspondent, Norman McInstry.
“The bake-a-plane project was complete late summer,” he writes. “First flight was a bad landing, which broke the right wing. I made new ones & added tape where needed. A pusher motor configuration proved better than tractor, so I made a pylon to be used both ways & attached by one sheetrock screw.
“Flying characteristics are very docile & predictable. I have actually caught a few thermals. It goes up very quickly due to extreme light weight, approximately 13 ounces.
Smaller Motor. “Motor is from an Ascent motor glider. I did install a brushless set-up but it was way too much power.
“Plywood molds are baked in the oven at 250° F for 20-25 minutes, removed & allowed to cool an hour before opening the molds.
“The stabilizer curvature is same as wing & can be baked at same time, centered in the mold. It is 10 inches long & approximately 5 inches wide. (This not a critical dimension.)”
Indoor Flying. With the weather turning nastier, Norman is also logging indoor flight time with his Heli-Max AXE CP mini electric helicopter. “Due to its contra-rotating blades, it’s quite easy to fly,” he says.
“I just completed a Klingberg Wing, which is yet to be test flown.
A Better Hang Glider. “In early 70s hang gliders were the craze, so Rol Klingberg decided to build a better mousetrap. Only one was ever built & flown in California. Future Flight decided to kit it & sold a few kits around 1974.”
This bit of history sent me off on a web search, where I found the following account (original in French; this is a Babelfish translation) by Rol Klingberg.
“There are no plans for the Klingberg Wing. I built the wing without plans (I never drew them) and used some gauges to make the parts. As a long time aeromodeler, pilot and engineer, I simply did not need a plan for a single prototype.
Badly Damaged. “The test pilot (Daryl ‘Monty’ Bell) sold the wing after a crash landing in Torrey Pines. The wing was damaged so badly that somebody other than me could not rebuild it.”
The original wing spanned nearly 39 feet and weighed 85 lbs. without instruments or parachute. The pilot occupied an opening in the center of the wing, out of the airstream. With a high glide ratio, Klingberg hoped his design would beat the world distance record for a foot-launched glider.
It had flown a number of test flights, totaling about 5 hours, before the big crash.
In addition to learning about Klingberg and his wing, I got sidetracked into reading about the Horten twist and drag and airfoil esoterica. If I understand correctly, the Klingberg design used a small amount of twist in the wing to control washout. This twist design was pioneered by Walter and Reimar Horten in some very streamlined 1940s flying wing designs which sailplane enthusiasts still savor.
Slimmer Wing. The Future Flight kit is a 2-meter version of the Klingberg Wing. It has a much slimmer chord than the wings I’ve flown.
And now back to Norman.
“Paul Maranaccio, one of my Cape Cod neighbors, bought two kits & kept them in limbo until 2006, when he built one. It had a most remarkable glide, maybe the best I have ever seen! From initial hand launch shoulder high, this thing went about 250 feet straight out before alighting.
“Paul later equipped it with electric motor, but it did not fly as well with extra weight.
“When I moved to New Hampshire, Paul gave me his second kit. I modified it slightly by using strip ailerons instead of built-in ones as per plans. I shall later install a small motor on a pylon at the center of gravity. My model weighs 25 ounces.”
Tags: Airplanes, Crashes, Flying, Helicopters, People, Radio Control, Wings.