RE: 1/5 Pepsi Chipmunk - Build
Ari,
My Chipmunk plans show a Zenoah G23 (earlier version of the G26) fitted on the plan view (model as seen from above) with only the carburetor exposed through the side of the cowl.......remember the full size standard version (RAF or RCAF) has a much narrower cowl than the high powered hotted up aerobatic Pepsi and Pennzoil. Have a look at Apache Aviation's website which shows all the variations.
The cowl starts the same size as the firewall (+/- 6'' and reduces to about 5'' at the carb.
I guess a lot depends on what silencer/ muffler you are thinking of using as the plans do not show this. The stock muffler is very flat and would probably fit.
All Airforce Chipmunks have fixed gear, only the Pennzoil had retracts(??)
We have two here at nearbye RAF base. They are used to train pilots learning to fly Spifires for the Battle of Britain memorial flight.
Ron