bob27s
Posts: 4949
Joined: 4/9/2002
From: Cleveland,
OH, USA
Status: offline
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quote:
ORIGINAL: Mark 5
Hello,bob27s,I have to agree with you.The YS60 is one of the strongest 60's out there.They are also very dependable,too bad this engine is no longer available. Razor-RCU,do you really think that a jett50 has more power than a YS 60?You have got to be kidding! The jett50 is one great engine,but more power than a YS60, I dont think so.Unless you sprinkle a little pixie dust on jett 50,then it would be more powerfull than the OS90DF. 
Razor is not all that far off base... but making a statement like that either way would require some qualification.
The SJ50 and SJ60L are quite powerful. The SJ-60LX even more so.
Replace the standard jett-stream muffler with a full size pipe, and there is more to be had.
(In fact, the SJ-60L and SJ-60LX have gained some favor with the SPA and BPA pattern organizations - replacing in some aircraft what were in the historical aircraft OS-FSR, Rossi, Webra and YS .61 engines. )
The engines are designed for different applications, and different RPM ranges.
If you went just by HP numbers calculated on a calibrated dyno, the SJ50 and YS60 engines might look pretty much equal.
But when you look at the rpm curve and where the HP is developed at, you see the divergence in application.
For speed, a smaller diameter prop is prefered, spinning at higher rpm (generalized). The SJ50 or SJ60 engines are better suited for that than the YS60 is. Keeping that prop disk area to a mimimum is a significant drag-reduction.
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Bob Brassell
Jett Engineering - Engine Mfg Support Forum Host
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Printable Version
All Forums >> RC Airplanes >> Extreme Speed Prop Planes >> RE: A NEW PATRIOT IS BORN!!! 
RE: A NEW PATRIOT IS BORN!!! - 
Ihope you dont rip the covering off with those high speed low inverted passes of yours. 
