Offbeat (sorry) Drone post

I have an old (obviously) Drone Diesel which may be over-the-hill. I haven't tried to run it for years, but it feels "soft". Who can chrome the cylinder to restore compression?

I've often wondered how you adjusted these, with no contrapiston..

Well, you just twiddle the needle until the thing goes "zing-zingg-zinngg" and try a flight. Then you re-adjust from there.

Allen Heinrich (Aerodyne) used to offer a replacement head with an adjustable contra-piston, and I'm trying to get one even now. Arne Hendt made a half-size "mini-Drone" replica (about .035 c.i.) which has the adjustable contra-piston. I haven't had the guts to run mine, yet.

If I can get the big 'un working again, I hope to build big-and-little copies of the plane Bob Tucker won the '47 Nats Stunt title with. Ought to make an interesting display . . .

>I've often wondered how you adjusted these, with no contrapiston..

Someone mentioned on a thread one time that they would adjust the ether/kerosene ratio until it ran well. I suspect that the ratio would depend on what size prop you were using.
I have not tried this. I do not have a Drone.

I have 2 Drone .29 ball bearing engines. One fixed compression the other variable compression. Both run very well but vibrate quite a bit. The variable compression head makes starting easier. I use castor oil content to vary the compression of the fixed head drone. The castings on these engines look heavy but the metal is soft. With the vibration the tendency is to really bolt these down. Be careful mounting these engines in test stands and planes as it is VERY easy to distort the case. Avoid test stands with a wood or metal bar clamping the mounting lugs on the B.B. version. Any slight distortion causes hard starting, low power and dirty exhaust oil. A drone .29 B.B. with worn bearngs show similar problems. Bearings are easily available and simple to replace. Be careful with the Aerodyne replacement head screws. These heads work very well but the screws provided are too short. With a balanced prop, correct mounting and good fuel Drone .29 B.B. makes all kinds of torque and is an easy to handle engine. Andy

Hi Ralph:
Bobby Oge can chrome you Drone cylinder and fit the piston to the cylinder. I am sending you this reply from my workplace. If someone else doesn't give you Bobby's address, I will post it to you in a day or two. Happy Holidays, Bud Brautlecht