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1. 08:03 PM - Re: Vibration(?) problems (jerb)
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| Subject: | Re: Vibration(?) problems |
--> Engines-List message posted by: jerb <ulflyer@verizon.net>
What type of engine, gear box model, ratio and prop brand and # blades do
you have?
jerb
At 09:10 AM 3/14/05 -0600, you wrote:
>--> Engines-List message posted by: AI Nut <ainut@hiwaay.net>
>
>Since the engine sounds smooth without the prop attached, it sounds as
>if you're hitting a resonance zone. If strong enough, these can destroy
>engine and prop on the ground, and cause you to crash if in flight.
>Avoid that rpm range unless you can change the resonance frequency to
>something above the engines upper rpm limit or down in the 300-500 rpm
>range. That might be difficult in your situation.
>
>
>Peter Cowan/Lexy Cameron wrote:
>
> >--> Engines-List message posted by: "Peter Cowan/Lexy Cameron"
> <cowcam@pipcom.com>
> >
> >My "proven" Rotax 912 80hp "aircraft" engine has a very annoying
> >problem. At most rpm's it is fairly smooth but between 3800 to
> >4000 it feels like it is running very rough. Before I did some
> >updates to the gear box I described it as knocking it was that
> >bad. After the updates (overload clutch, new bellvilles etc) it
> >is just rough. It is not carb synch; it is not ignition. I have
> >checked the balance of the prop and set the pitch on the 72"
> >Warp. If I take the prop off and runn the engine it runs pretty
> >smooth with just a hint of vibration at the 3800 range.
> >Can anyone suggest what this means and the fix? I will double
> >check prop pitch and balance and I'd like to try a three blade.
> >Anyone know how significent the moment of inertia issue is which
> >PowerFin props say is one of their advantages over Warp?
> >And Hello ED. I'm watching the progress of a 75hp two rotor about
> >to be marketed.
> >Thanks
> >Peter
> >
> >
> >
> >
>
>
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