I'm thinking a Cox Queen Bee .074 (will have to check to be sure...)


Edit: Yep...it is...
http://www.rcuniverse.com/forum/1-2-...bee-074-a.html

I concur in that it is a Cox Queen Bee .074 RC engine.

Well it looks kinda cool.

Yes 100% Cox Queen bee .074 engine. same power of a golden bee/black widow but with a not so good carb. It was heavy but did what it was designed for and that was to be a throttled 1/2A engine.

There isn't anything really wrong with the Queen Bee engines. Cox needed to have a engine with RC throttle capability and a muffler on it for the current rules where mufflers are required at the flying fields. But a muffler on a 1/2a engine robs a fair amount of power from it. So they had to increase the displacement to compensate. Also going with a glow plug hurt performance slightly which also meant the displacement had to be larger too. So the engine wound up being .074 cubic inch displacement to compensate. The reed valve intake is actually not a bad thing either as you can run the engine forward or in reverse, like for using in a pusher application. Yes the engine's performance is more like a regular .049 engine but if you put a muffler on a regular .049 engine then it doesn't perform as well as the .074 engine does. Unfortunately the Cox Queen Bee wasn't popular and it wound up being discontinued after a while.

Throw a Cox 09 TD high compression head on it for a decent upgrade in performance. Also do not be afraid to add nitro to the mix 25% would not be out of line and 30% will get it into better performance area. Other plugs are the Fox 09 and the Fox 10. Some have said that the Gilbert 074 head also fits.

Dennis

I'm surprised after all the trouble and sacrifices Cox made in engineering this engine to add a throttle control and muffler that they didn't add a pressure tap to the muffler to allow a pressurized fuel tank? I would think that would be a huge help to make them more user friendly.

Yes that is a interesting thought as to why they didn't have a muffler pressure tap on the engine for pressurizing the fuel tank. Probably the accountants got involved in cost reduction at the time. But the carburetor is in the rear and much more close to the fuel tank though, so maybe it wasn't a problem.

Well things similar were done in the past. Fox originally made a .049 engine for COMET when Comet was going to sell some RTF control line planes. But the planes came out on the heavy side, so Fox had to up the displacement to make the engines .07's instead in order to compensate for the added weight.

I suspect that the Gilbert .07 engines for the Gilbert RTF control line planes had the same problem in that they likely upped the displacement from .049 to .07 to compensate too. The .11's were probably .09's at first for the same reason.

The .06 engines and .07 engines we see that were being sold probably had the same problems with mufflers and RC throttles, glow plugs, etc. Thus they had upped the displacement on them from .049 to compensate too. You see that with the Norvel .049 and .06 engines and the Thunder Tiger .07 engine too.