flyrotary@lancaironline.net Mailing List Archive

Tom is that a PP 3 rotor? If side port, is it ported in any way?

I am not denying all that you say. But 2 rotors are way more readily available and my friend has one already, allegedly basically brand new. We do need to do some tests on it, but if it is a good motor, I think he will want to avoid trying to source a 3 rotor or build a PP out of his 2 rotor. But he thinks he needs more power, hence the turbo option.

Question about turbo control for you all. If your goal is very modest boost at sea level, but normalizing at altitude, can you not just use a boost controller and set a MAP as in manifold absolute pressure and stick to that? Say you set it for 3 psi (roughly 18 psi absolute), that would be very modest boost at sea level, but at altitude, the turbo would try to stick to that - maybe it is 6 psi or whatever over atmospheric, but the same absolute pressure. Is there any reason to feel you are stressing the motor if you are sticking to reasonable boost like that?

— James

On Oct 7, 2015, at 12:33 PM, Tom Mann <flyrotary@lancaironline.net> wrote:

Whenever the topic comes up about adding a turbo to a Rotary I go back to what was the reasoning I used when making the decision to go Rotary in the first place.

My reasoning was to eliminate as much mechanical complexity as I possibly could. If I added a turbo then the level of complexity (and weight) went up.

I reasoned that if I needed (or just plain wanted) additional power, I would just add another rotor. That actually gives me more power that the turbo for where I need it most and the weight comparison is negligible for the trade-off in power/complexity.

I believe that a 2 rotor (using Mistral Engines as a benchmark) produces 190hp N/A (291 lbs) vs. 230hp Turbo (328 lb). The three rotor generates 300 hp @ 375 lb so yes, it’s it’s roughly +50 lbs but +70 hp as well without a significant increase in complexity.

I opted for the 3-rotor solution. Less things to go wrong (which is important to me.)

T Mann