I was in a tinkering mood yesterday and I decided to satisfy an old curiosity, mainly the title of this thread.
I opened up a new Brodak .40 and procured an OS FP carb, graciously loaned to me by George Waters. After removing the Brodak venturi and NVA, I took a few cursory measurements and found that the carb would need a very slight modification to fit (I did not want to modify the engine case).
It took all of 15 minutes to alter the carb and it was a perfect fit.
I then put it on the test stand and ran it in per the supplied instructions.
After approximately 30 minutes of run-in time, I checked its behavior as a throttled engine.
I could not have been more pleased with the results. With an 11-5 Top Flite wood, it ran perfectly from around 3,800 to 9,800 RPM, with excellent response anywhere in between.
So, why did I really do this? To encourage people to get into RC?
Nahhhhhhhhhhhhhh - you all know me better than that.
As many of you must have noticed, there is a lot of recent interest in CL scale - all the way from Fun to Precision. Lots of profile planes for this size engine. Many if not all people use three-line systems for engine speed control.
So, why not take one of the most popular CL engines on the market and apply it to use in scale?
Actually, a great many of the CL flyers also dabble in RC - here is just another alternate powerplant.
Besides, it was fun to tinker!!!!!!
Bob Z.