Mailing List flyrotary@lancaironline.net Message #50288
From: Mike Wills <rv-4mike@cox.net>
Subject: Re: [FlyRotary] Re: Performance 68x72 prop. [FlyRotary] Re: TB size, Travel and Power
Date: Mon, 8 Mar 2010 19:30:18 -0800
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Thanks for the input Al. The small delta seems to be abnormal compared to the experiences of most others so good to know I'm not the only one. Since Ed's old prop has less pitch than my current, seems like that would be a good test. Still planning on some intake mods, mostly to get enough room to fit a proper air cleaner. So I'm going to focus on that first.
 
Mike

From: Al Gietzen
Sent: Sunday, March 07, 2010 10:25 PM
Subject: [FlyRotary] Re: Performance 68x72 prop. [FlyRotary] Re: TB size, Travel and Power

 

Thanks. As I've mentioned before my static RPM is in the same ballpark (5300) but in level flight only comes up to a max of around 5700 - 5800. So if I could bolt your prop on and get up to 6400, that would be a pretty dramatic change. The small delta between static and level flight RPM is another reason I suspect something weird going on in the engine limiting power.

Mike

 

Mike;

 

That doesn’t really seem out of line to me.  IIRC; when I had the 85 pitch prop the static and max level were quite similar to what you’re getting – maybe just a bit higher.  I think a bit less prop will get you close to where you want to be.  I don’t know what the tradeoffs are between less pitch or shorter blade; but I’m thinking less pitch is the way to go.

 

Of course some more power would do the job as well.

 

Al

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