A final and equally interesting use for the Baby Biwinger(above left) would be to build one as part of a display or as a unique and distinctive display stand for your K&B .020 Infant if you have an antique engine collection. But be warned, there are those out there who may be tempted to try and fly this cute little rascal.
very light. As can be seen from the lower part of the table, all the major components need- ed to make a suitable R/C installation for the Baby Biwinger is less than the weight of the Cox Tee Dee .010 engine and prop! You might have to lengthen the nose a bit,
and use lighter and thinner gages of mater- ial for the wings, fuselage sides and tail sur- faces, but that would also result in a lighter model. You won’t need the 1⁄8-inch plywood firewall and the landing gear can now be 1⁄32 or .020 piano wire instead of the beefier orig- inal construction and you won’t need all that dope on the model to protect it from the ex- haust residue from the engine. Replace the very tough solid rubber and
aluminum Perfect brand wheels with the light plastic wheels from a rubber model like a Sleek Streak will further lighten the mod- el. So the option of an “Electronic String” tied to the Baby Biwinger is now a very strong possibility. If you can find some real- ly thin gages of the foam material out there in your area, then material substitutions are also a strong possibility. The possibility of an R/C Baby Biwinger that is half the weight of the original model shown is a very real possibility. If you build the F/F version as originally designed, flying the model was always re- ally easy. Just glide test the model over the proverbial tall grass before even thinking about a powered flight. If you have built the model correctly it should not need very much weight to get it to balance right. Both of mine required none at all that I can remember. When you have a nice smooth glide that
looks straight or like the start of a big circle to the right you are ready for your first pow- ered flight. Try to set the needle valve to a fairly fat rich setting for the first few flights and launch into the wind with a level or slightly nose high attitude and the wings banked to the left. Both of my models rolled into a left climbing spiral turn and except for the addition of some downthrust, no other changes were required. It flew just like a Joe Wagner Dakota and was as if it was all au- tomatic. Just remember to keep the engine
FLYING MODELS
and none of these three engines is easily replaceable any more. Close up (above right) of the three candidate glow engines that could be used for the glow F/F version of this project. A Cox Tee Dee .020 while a possible fit is not recommended at this time.... A modeler’s gotta know his limitations.
runs short though. This plane is a lot lighter than the Dakota and may have a better glide as well with its simple cambered balsa sheet airfoil. I’ve often been asked what is the secret to working with these tiny engines so success- fully. I have to say there is no real secret to working with 1⁄2A engines and smaller other than some good housekeeping. The following four cardinal rules have served me well over my lifetime. 1. Keep your engine scrupulously clean. I usually let the tank run dry after the last flight of the day and use a very light after run oil as a preservative, pulling the engine through several times with the spring starter if the engine has one. If the engine has been in the “dirt” or some other such mishap, do not try to turn the engine, but take it home and completely disassemble it on a clean cloth and clean all components throughly. Then oil it and reassemble your treasure. 2. Use only clean fresh fuel. If there is
“stuff” floating around in the fuel from your can, get rid of it. The tiny orifices in the ven- turi of these engines won’t tolerate this ma- terial and your flying day will be ruined.
3. Good strong battery with clean con-
tacts. If the plug does not glow with a bright orange element, you are in for a bad day. 4. Good glow plug. No glow, no fire. In the final analysis, the original model
may have been good with the K&B .020 In- fant it was designed for which met with ac- claim when Lud appeared at the the 1951 Nats with a whole cardboard box full of them. The example that we ran tached out at 10,000 rpm max with a 4.8 diameter prop, but it is absolutely spectacular with a Cox TD .010 on the front end and a really large flying field to accommodate it. Several of my Tee Dee .010s have been tached at well over 26,000 rpm with that little 3-inch diameter prop. But if you don’t have a huge field at your disposal then an electronic “string” on your model may be the optimum solution. Just use the very lightest materials you can find when building your Biwinger and success will be yours. All within a Peanut Scale sized 13-inch wing span and budget that may be peanut sized but not to be confined to the “Peanut Gallery” when it comes to flight performance.
Weights for R/C Option Item Cox Tee Dee .010 with small back and prop
K&B .020 Infant engine with prop (note weight difference) Cox Pee Wee .020 with prop (reference) Complete airframe without engine and prop Second completed Baby Biwinger Parkzone PKZ3624 motor and gear box GWS EP5043 prop and spinner Spektrum AR6400 Ultra Microlite Rx
Spektrum AS2000L linear servo (not required for this model) 110 mAh Li-Po battery
Weight
18 grams 32 grams 27 grams 46 grams 64 grams 6 grams 2 grams
3.9 grams 1.7 grams 3 grams
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