September 21, 2023
Glow engines / My planes / Vintage F3A

New engine for Sun Fli

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I wasn’t really happy with the performance of the O.S .65 AX engine with 11 inch propellers so I’ve fitted a brand new O.S .61 FSR ABC engine that will use a Tore Paulsen style pipe and Hatori aluminum header.

This engine has been in its box since the 1980s and will finally see service.
I tried a Hatori 90NA muffler on the O.S .65 AX which gave lots of power but it was quite loud.
Tore Paulsen silent pipe custom made by Øyvind Andreassen here in Moss
Hatori header. The pipe is fitted at the recommended (by Tore Paulsen) length from the exhaust port, which is 22 cm.
Break-in, it ran through 5 full tanks of 10 % nitro fuel and reached 10500 RPM on an APC 11×11. I backed off just a little and it now turns at 10200 RPM and is very stable. I think the pipe needs to be longer, it should be able to reach 12000 RPM on this setup.