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Prefered engine qualities?

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Old 06-03-2010, 11:47 PM
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RPool
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Default Prefered engine qualities?

Which characteristic is preferable from an engine for precision aerobatics...high reving with low pitch prop, or lots of "grunt" and a higher pitched prop? I just got my 73" SBach and I'm struggling with engine choice. I'm torn between several 30 cc engines and a torque(y) 42 cc coming out this month...
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Old 06-04-2010, 09:22 AM
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ORIGINAL: RPool

Which characteristic is preferable from an engine for precision aerobatics...high reving with low pitch prop, or lots of ''grunt'' and a higher pitched prop? I just got my 73'' SBach and I'm struggling with engine choice. I'm torn between several 30 cc engines and a torque(y) 42 cc coming out this month...
I have a thread in the Pattern Forum on the care and feeding of the SAP180HP. If your plane will end up around 12 lbs give or take, consider this engine on pipe. Lots of output. The engine's field manners are impeccable. Very lightweight set-up that I am using in 2 meter Pattern planes. The SAP IBEC is also something to consider. I helped test this device that good friend Ed Alt designed, and it works superbly. Weight savings due to the IBEC is around 5 ozs (no extra battery and switch needed)

The 42cc engine I had my eye on is the one that AussieStevie has talked about from Australia I would guess. He has not answered any of my question in regard to the engne so I will no longer consider this an option. There is the MT line also that a bunch of fellows have had nothing but grief with....also not an option
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Old 06-04-2010, 03:16 PM
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You are reading my mind! Unfortunately I have no pipe tunnel in my 73" Pilot RC SBach. It is listed as a feature, but it's not there! I actually had the Syssa and IBEC in my "cart" on the website, but baulked. The plane is supposed to be 10.5 lbs...what do you think?
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Old 06-04-2010, 03:54 PM
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Quote:
ORIGINAL: RPool

You are reading my mind! Unfortunately I have no pipe tunnel in my 73'' Pilot RC SBach. It is listed as a feature, but it's not there! I actually had the Syssa and IBEC in my ''cart'' on the website, but baulked. The plane is supposed to be 10.5 lbs...what do you think?
You can run the engine on its included muffler and turn a smaller prop. It would work fine with something like a 17x8-10, 18x6-8 or 19x6 on muffler. Expected rpms in the mid 8's

The pipe allows more pitch to be used. I use a 17x12 apc and have run 18.1x10 apc and 19x10 hybrid that I make myself. All work great on pipe. My rpm is in the low-mid 8's on pipe.

If the plane has no tunnel built-in, then your options may be limited to running muffler alone.

My pattern planes and the 78" EF Extra have superb performance on pipe. Pattern planes are 10.5 lbs and Ef Extra is just under 11.5 lbs. Your Sback weight is on par with these.

The SAP will take 3-4 gallons of regular 87 Octn gas to break in. I use BelRay MC-1 synthetic motorcycle oil at 50:1. Buy at motrcycle shops. SAP recommends the Amsoil Saber Pro synthetic at about 85:1. I've run both and sticking with the BelRay

Before making the jump spend a couple hours perusing through the thread....lots of good info there. Bottom line, it's a great engine and is made here in Conn. Todd Syssa gives great service too.

Good luck and let me know if I can help
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