Props and RPM

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TerenceE
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Props and RPM

Postby TerenceE » Thu Aug 13, 2015 11:50 am

Hi guys

I need some advice on the following:

Windlass trike with 503 UL DCDI, B type gearbox and Aquilla wing. The prop is an old Geo Kelly 63-32 wooden prop that was serviced last year by Peter de Necker and has barely worked since. Prop looks great. Now the problem is I have a MGL Avionics Smart Single EMS 503 that shows me 7000rpm during take-off. I downloaded the the Rotax manuals from the internet and they show peak performance of 37kW at around 6500rpm and give a max allowable rpm of 6800. My questions are:

1. Am I doing damage to the engine at 7000rpm for a few seconds during take-off? I don't want to cause long term problems.
2. Can it be that the EMS Rev counter can be so far out?

I spoke to Peter de Necker and he was concerned about the high revs and recommended to stay below 6700rpm. He also said he doesn't want to sound like a salesman, but he would recommend a prop with a higher pitch. He says a 63-35 will do better and provide a higher cruise speed with the faster Aquilla wing. Makes sense to me! Any thoughts will be appreciated.

Cheers
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meglin
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Re: Props and RPM

Postby meglin » Mon Aug 17, 2015 11:57 am

In any case it is better to have a resettable step to fully utilize the power of the engine.
Sabre 1600 mm 63 "will be just right.
It will be quieter, softer rod will be greater.
7000 - this is not normal, often can not be used.
It is necessary to set the fin so that the earth was 6300-6500.
Not more.

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kloot piloot
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Re: Props and RPM

Postby kloot piloot » Mon Aug 17, 2015 7:39 pm

Am I doing damage to the engine at 7000rpm for a few seconds during take-off?
Don't do it.
Roel Jansen
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