-=> Quoting Roger Marshall to Ken Ellison <=-
 RM> Hi, Ken...
 KE> was in particular on my PT-40.  I have a GS-40 on it and was running
 KE> a 10 X 6 on it.  After a few flights I had some pilots ask what size
 KE> prop I was using and they said I should use a 10 X 8.  I tried it and
 RM> knows what he's talking about so his advice is very good.  As to using
 RM> a 10x6 vs. a 10x8 prop on a GS-40...the ST line of engines are ALL
 RM> very good, well-made, and very powerful.  The GS-40 will pull the 10x8
 RM> very easily without overloading the engine - you see, overloading is
 RM> EXACTLY what we must avoid because it doesn't allow the engine to
 RM> reach its normal RPM, stresses the metal due to overheating, and
 RM> quickly will ruin the engine. A powerful engine can use the largest
 RM> prop in the range but a weak engine (like the OS-40HP, the Thunder
 RM> Tiger, and some others) will suffer badly, they will have to use the
 RM> lowest dia/pitch prop in the size category. Many modelers will
 RM> experiment with a range of props with their engines to find what works
 RM> best - but always after the engine is well broken in and usually the
 RM> testing is done with a tachometer.  Good luck and TTYL - Roger 
 I run the APC 10X7 on my piped GS-45 ST engine and get 14K on the ground.
 I would say that a 10X8 on the 40 would be too much, I would use the 10X6
 or maybe the 11X6 or 11X5, I don't think speed is really the answer
 for a PT-40. I did try the 10X8 on my st GS45 and got too much speed.
                      Adam
... I tried OS/2 once, but I didn't inhale.
--- Blue Wave/TG v2.12
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