What rpm should an OS .91FS w/pump turn
08-09-2002, 10:31 PM
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What rpm should an OS .91FS w/pump turn
I'm just about to install a "new" used OS .91SF w/ pump into a new .60 Spit. I had it on the test stand and it would turn a 14x8 wood MA prop at 8,100-8,200 full throttle and idle down to 2,300.
Having no experience with this set-up I don't know if that's good or bad.
Also, the head seemed a little hot despite the fact that she was pumping a nice trail of smoke.
Can anyone tell me how this compares to their .91?
Having no experience with this set-up I don't know if that's good or bad.
Also, the head seemed a little hot despite the fact that she was pumping a nice trail of smoke.
Can anyone tell me how this compares to their .91?
08-09-2002, 11:01 PM
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What rpm should an OS .91FS w/pump turn
I have a YS-91AC in a Variant running a Graupner 14 X 7 p/n 1316/36/18 and it turns about 9000 which is excellent. My frineds who run these enignes and central Hobbies recommend this prop. I can recommend a good site to purchase these very reasonable. rccreations.com.
08-10-2002, 02:22 PM
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What rpm should an OS .91FS w/pump turn
I have been flying the OS 91 Surpass wo/pump in a Ultra Sport 60. I fly a 13x9 APC prop and it turns about 9700 to 9800 rpm. I just flew it 4 times yesterday (Fri). I did the break-in with a 13x8 APC prop and it went to 10,400 rpm at normal needle valve setting. I did not like the vibration and some on RCU said this was to high rpm. I was told to maintain rpm on ground slightly below 10,000 rpm - ok, fine with me. This is my first 4 cycle. I can't say I'm thrilled. I like their reliability. Plane has about 15 to 20 flights, no dead sticks, and those in our club say it runs perfect, but I'm to much into the deep throated whine of powerhouse 2 cycle's. Could be.
