Mailing List flyrotary@lancaironline.net Message #50727
From: George Lendich <lendich@aanet.com.au>
Subject: Re: [FlyRotary] Tuned lengths
Date: Thu, 1 Apr 2010 16:31:59 +1000
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
 Al,
Your probably right, but for me, I'm planning a single rotor, a 2 rotor is way too heavy as it not only affects the  weight and balance it puts me over a certain weight limit. If I were to use a 2 rotor I might not even worry as 160 hp would be more than adequate - then there's those who like to squeeze the efficiencies as much as possible, like Ed. Then there's those who do it because it can be done. I also find it interesting research.
George (down under)

So let me just play devils advocate and throw this in here.

 

I designed my intake manifold to be compact, lightweight, and fit into the cowl without any contusions or bumps. I designed a compact tangential muffler, and a secondary muffler, for light weight and suppression of the noise. No effort to ‘tune’ on either end.

 

The result is that I get a very flat torque curve, and about 90 HP per rotor at 6300, using the 9.7 turbo rotors in a NA engine (actual dyno data).  It is also one of the quietest rotarys around and the exhaust system is still solid and sound after 180 hrs of operation.

 

No; I’m not bragging – and I don’t doubt that a few more HP could be squeezed out over a small rpm range with tuning. The point is simply – how much time and effort do you want to put into the misty netherland of tuning the intake and exhaust?  Maybe focus on lightweight and durable design.

 

Just a thought,

 

Al G

 

 

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