Best Prop/Fuel for OS Surpass 91: max speed

Right now I run 10% towerpower and use a 14x8. Not very fast. How much
faster will a 60 size warbird go with a 13x9 and 15% fuel?
Joel
Reply to
Joel
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Right now I run 10% towerpower and use a 14x8. Not very fast. How much faster will a 60 size warbird go with a 13x9 and 15% fuel?
Joel ================================= Looking at the rpm numbers others have reported on
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the engine should be turning around 8400 currently. That is theoretically about 63 mph.
They don't have any info for the 13x9 @15%. Unless you can find rpm numbers from someone, you're going to just have to try it to find out. At 8400, the 13x9 works out to 71 mph. At 9000, if the engine will turn it, you'd theoretically go 76 mph. A12x11 is another recommended prop for the engine, and it works out to 87 mph at 8400.
The mph numbers come from thrusthp, which is a free download.
Reply to
Carrell
I used to race an OS .91 Surpass in an EZ-P-51. I settled on an APC 12.5X9 Pattern prop and 40% Powermaster. It would turn that prop around 10.9K on the ground and unloaded quite a bit in the air. If you want max speed with 15% nitro, try a 12X8. Don't be afraid to rev the engine. They will handle 12K on the ground just fine. Oh, sure, there are those who will have dire predictions about running that fast but I can just about guarantee that none of them have actually done it.
If its speed you want, nitro is what you need.
Reply to
Paul McIntosh
Carrell,
A link is generally helpful!
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Jim Lilly - Team Z
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Using - Virtual Access(OLR), ZAP 4.0, & WinXP Pro w/SP1
Reply to
Jim Lilly
Carrell,
A link is generally helpful!
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Jim Lilly - Team Z ======================== I didn't have the link handy and was ready to go to sleep. Anyone who cares could go to any search engine and type 'thrusthp' and have the link in 10 seconds.
Reply to
Carrell
Don't forget the diameter of your plane. The prop tips should be quite a bit larger. also a wide bladed prop can help if your hull is too big for the propsize. Seen good results from hand made props. They are straight the first 4 inches.
Reply to
Maarten

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