Stuka Stunt Main Forum · 26 of 26 known posts recovered
If I remember correctly, Fox included several venturi inserts. It looks like you got one of the bigger ones, and it may have trouble running on suction. You'll also have to purchase a custom muffler with strap, too.
The engine was not one of Fox's great successes. It was fairly heavy. As far as I know, it is not particularly desired by collectors. You or your friend might have better luck with one of Fox's current 40's - they're way, way better, and some are available specially tuned for stunt.
"Fox 40 CL (1972). George Aldrich was working with Fox on the design of this motor. Motor is excellent condition, it has been reworked by Lew Wollard, and test run by him. ST style needle valve assemby. No box. Comes with a 20.00 custom made muffler"
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The best flying stock kit SIG Super Chipmunks (2 total) I've seen were powered by this engine. The set up for these was 60'×.015" lines, Hot Rock, Top Flite 11×6 (old style) Super-M, Fox SuperFuel, with the launch RPM unknown (I had no tach in those days.), but set at the edge of the 4 to 2 break. The first one was the plane a local flyer, Ken Snyder, used to learn the pattern. The second was a replacement for the first that helped him perfect it. Both were excellent flyers with (estimated) slow laps.
I have wanted one since I saw those planes fly. (This was in the days prior to a muffler requirement. I haven't yet tried to find a muffler that will work for this engine.)I don't recognize the venturi set up on the one you picture. It looks like it may have been modified, or that it is a different version than that with which I'm familiar.
I am attaching shots of the two (one is NIB) Fox .40 Stunts that I have picked up over the last few years via da Bay, just for comparison purposes. Have fun.
Tim;
It looks as if your friend has the RC version (crudely converted to CL) that was designed by George Aldrich. The RC version had a carb that was press fitted into the case. The CL version had the longer venturi. Looks like someone press fitted some tubing into your friends to create a venturi and then put a second piece of tubing into it to get the choke area right.
I remember for about a year seeing one of these in the case of the local hobby shop with a price of $19.99 on it during the early 1970s. I had to have it. By the time I had saved the money the LHS had sold it. Sad face.
About two years before he passed, George passed on to me that he had in fact designed the engine. George related that he incorporated some schneurle technology into it, but did not call it a true schneurle ported engine. Duke Fox then made some mods to the design that GMA did not approve of. The engine was not a big seller and was only made for a few years. It was soon replaced by the "large case" Fox 40 and 45 schneurle ported engines.
I have since acquired a couple of these engines. This is another mill that had tons of potential. Had it been better balanced it might have really made a mark in CL Stunt. But, when one considered that the ST G21-46 was available at the same time, serious stunt flyers opted for the ST.
V/r
Bob Kruger
Bigiron
Currell
George told me years ago that Duke had originally planned for it to be a Pylon engine (you can see where the rear ball bearing would have gone), but soon gave up and told George to turn it into a stunt engine.
Biggest problem was weight, but it did have grunt to it. The stated fact that the ST 46 was being used and there wasn't a big market for a heavier 40 size alternative was the probable cause of it's lack of popularity.
I have two; one NIB, and one that was R/C but the carb was removed and the C/L insert was put in with a needle valve. I used it to power my T-Bird II for a long time. It has a fantastic 4-2 break.
Bill <><
When the character of a man is not clear to you, look at his friends.
Japanese Proverb
It is heavy and wide as everyone seems to agree. From what I can tell....should be a great stunt engine. Just need to find the right model for it. Any thoughts?
Mike;
I don't know about your engine, but my GMA Fox 40s are real shakers. This may cause some fuel foaming problems - as high vibration engines often do on a profile nose. Bob Reeves seemed to have broken the code on how to run it on a profile back in the 1970s - so he may have some good tips for you.
The plan for my Fox 40 was to build a modified Oriental with a longer tail moment, larger control surfaces, and a slightly thicker airfoil. The nose would also be a little wider to accomodate wider case. I ended up keeping the fuse the same width and running an LA 46 in it. The LA 46 gives good power, doesn't need special fuel, and is much better balanced. However, I still have the plans I did for my Fox 40 and may crank one out this winter.
It is regretable that Duke Fox never really broke the code on balancing an engine.
V/r
Bob
I have popped of the backplate of the one I have and it looks as though Lew Wollard has started the process. the crank has been lightened but the piston looks as though it has lightening possibilities left
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If I were to try that today I am sure it wouldn't work
All we need now is a picture of the Razorblade!
