flyrotary@lancaironline.net Mailing List Archive

I read through the thread on VAF; his motivation is to have totally redundant propulsion, without any of the various issues arising from L/R or F/R props. I dismissed his idea as being way too heavy for a single engine a/c. I totally missed the idea of splitting the engine into a pair of single rotors.I'll bet Richard can confirm that a 1-rotor can't come anywhere near half the weight of a 2-rotor, even with aluminum end plates, and you haven't yet doubled the starter, alternator, controller, etc weights.

Someone in South America did the concentric prop thing on an EZ about 15-20 years ago using small piston engines, and even flew it to OSH. So it obviously can be done, but I don't see a 1-rotor engine as being a viable path. Shame there aren't more of the smaller 2-rotor engines around to play with.

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On Sun, Aug 15, 2021 at 11:16 AM RES res12@fairpoint.net <flyrotary@lancaironline.net> wrote:

Ernest, you pretty much said it all.
Let me just add a few thing.
Since you have pretty much everything double, so are possible failure sources.
Why counter rotating propellers? Is there a power density issue?
Would have to spend millions and millions to getting that into the air.
I have been there done that at a much simpler scale, with just one rotor, all the way to safely fly it in my 700lb airplane.

There is a lot more to it!

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From: RV9flyer 13B Rotary rv9flyer13b@gmail.com
Sent: Sunday, August 15, 2021 8:10 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Interesting "Twin Pack" Rotary Demo Idea

An aero-engineer on the VANS Alternative Engine list posted his dream project on creating a Twin Pack single rotor to put in an RV-8. Some very creative thinking to bring it along this far IMO!

Doug

https://www.youtube.com/watch?v=kMxJ7G-lRhk