Extreme Speed Prop Planes Discuss the need for speed with fast prop planes (Screamin Demon, Diamond Dust, Shrikes or any REAL sound breakin'''' plane)

Prop Choice, Jett 90L, Patriot XL

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Old 09-19-2005, 06:04 PM
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kamakazie frank
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Default Prop Choice, Jett 90L, Patriot XL

Have flown my Patriot XL with The Jett 90L turning an 11 x 9 APC prop @ 13500 on the ground & its just not doing the trick for me.
The engine has about one gallon of fuel through it. I know this is a big bird and it just does not seem to be flying as fast as my expectations.
Just wondering what you guys are propping the 90L with this combination?
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Old 09-19-2005, 07:43 PM
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AirGar
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Default RE: Prop Choice, Jett 90L, Patriot XL

I run the APC 11x8 on my Jett 90L. That's the prop Dubb recomended.

Gary
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Old 09-20-2005, 06:27 AM
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kamakazie frank
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Default RE: Prop Choice, Jett 90L, Patriot XL

Thanks Airgar.

What rpm's where you running on the ground with the 11 x 8 prop?

KF
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Old 09-20-2005, 08:46 AM
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Default RE: Prop Choice, Jett 90L, Patriot XL

Frank,

Sounds like the engine is running right. Just not the right prop combo here.

Try going back to the baseline 12x6 to start with. The engine should turn over 14K with that prop, and will unload more in the air. That is the baseline prop for the engine, and will give you the best reference to work with. Once you see how it performs with that, you can compair the speed from other props.

Trying an 11x8 is probably a good idea too. Same thing, engine should be over 14K rpm.

I do not think the plane is accelerating enough to utilize the 11x9 here. Its a good prop, but the plane has to get up over 120 mph for it to work properly if it is lugging down to 13,500 on the ground - the engine has to be able to unload about 1000 rpm in the air, and my guess the patriot is not doing that. This prop does work ok on the Jett-90LX engine, but only because its turning 500 rpm more to start with.

The other way to go is down in diameter. The 10x10 turns up very nicely, and even try a 10x11. One jett 90 pilot out there is telling me he has 135mph with the 10x11 prop (I think he clipped down an 11x11 to get the rpm up). The small diameter may add 50 feet to your take-off roll, just so you are prepared.

The trick here ....... allow the engine to turn up over 14K rpm.

Bob
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Old 09-20-2005, 10:03 AM
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Default RE: Prop Choice, Jett 90L, Patriot XL

Thanks again Bob!

KF
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