I am very greatful that you supplied the fan.
I cannot take any credit for the idea, I may have machined up the bearing blocks etc to fit the fan into the housing and taking the drive off the mechanics and solved any issues that I had in doing the conversion but the thinking behind the mod was not done by myself, I can take credit only for my work that I've done.
I do think it is a fantastic idea.
Yes the mod didn't work as expected until i fitted the extended duct onto the engine, again this wasn't my idea.
I tried one and then two pipes as it didn't work as expected on this R22 and then the duct was fitted which gave the result we all are looking for.
The one pipe goes to the top of the engine directed at the engines cooling fan (this has worked via an electric fan on my Bell 222 with Morley F1 mechanics that I built a good few years ago)
the other pipe is directed at the carb, but I tried not to have it to close to the carb as I didn't want to cause any carb freezing issues
(I now know this isn't a problem)
As you say the 5 that was done all worked with great results and that is why I carried on with the hope that this R22 will fly without overheating with the doors on
The final testing was done on those realy warm days we've just had and the heli flies fine from start to the finish of the flight.
When I first had the heli I did try using an electric fan under the engine which did work and allowed me to fly doors on but the fans only lasted 3 flights until the heat of the engine destroyed the fan.
The part number for the duct is 104/24 and the guy's from the states that helped me use this on the later mid engined Bell 47 type mechanic'd R22
If you do take an older R22 apart to do the modification its worth having a set of layshaft bearings handy as they were very well worn on my R22.