Prop model and length options?

[mcjon77]

Hi guys,

For the Rotax builders and flyers, what propeller length (and model) are you using/planning to use? Also, is anyone planning on lengthening the landing gear an inch or so? I have been considering a 3 blade 64" Warp drive. Truth be told, I am about 2 years away from having to make the decision, though.

[SonexN76ET]

Anyone who is considering using a Rotax in a legacy Sonex please contact Sonex and request they develop and sell an engine mount for the Rotax. I plan on someday swapping my Aerovee for a Rotax (when I can afford it). I think that if enough of us request a Rotax mount the factory may produce one.

[Brett]

I'd buy one tommorow if they did.....

[garyb]

I am still building my Sonex Rotax its at the 90% stage now. I have increased the ground clearance by about 3.5" more than standard and I am using a 68" prop 64" would be okay with standard clearance.
Regards Gary.

[Brett]

Hi Gary,,, will really look forward to seeing your performance figures with that prop and engine combo.

[gammaxy]

Sonex told me a about a year ago that 60" diameter is their limit. Measuring from the plans, that looks to give about 9" of clearance without any deflection of the gear. Does anyone currently sell 60" propellers for the Rotax on a Sonex?

I played around with JavaProp to design optimal propellers for the ~2300rpm Rotax and estimated you get ~8% more thrust at Vy when you step up from 60" to 68". The differences in cruise is much smaller, so I imagine you could be happy with the smaller diameter.

Gary's longer landing gear seems like a good idea to me, something I'd strongly consider for larger propellers.

14 cfr 23.925 says:

(a) Ground clearance. There must be a clearance of at least seven inches (for each airplane with nose wheel landing gear) or nine inches (for each airplane with tail wheel landing gear) between each propeller and the ground with the landing gear statically deflected and in the level, normal takeoff, or taxing attitude, whichever is most critical. In addition, for each airplane with conventional landing gear struts using fluid or mechanical means for absorbing landing shocks, there must be positive clearance between the propeller and the ground in the level takeoff attitude with the critical tire completely deflated and the corresponding landing gear strut bottomed. Positive clearance for airplanes using leaf spring struts is shown with a deflection correspondingto 1.5g.

[WaiexN143NM]

Hi all,
Who was posting a year ago about using a custom ring mount to convert from an aerovee mount to a rotax mount? Is that you gary?
Thanks chris for always good info posts.
WaiexN143NM
Michael

[mcjon77]

Anyone who is considering using a Rotax in a legacy Sonex please contact Sonex and request they develop and sell an engine mount for the Rotax. I plan on someday swapping my Aerovee for a Rotax (when I can afford it). I think that if enough of us request a Rotax mount the factory may produce one.

The engine mount issue was one of my biggest concerns. When they came out with the B model conversion kit and I looked at the features (including a rotax engine mount option) I have decided to go that route. I will probably order the b conversion kit next year.

[Concorde]

Anyone who is considering using a Rotax in a legacy Sonex please contact Sonex and request they develop and sell an engine mount for the Rotax. I plan on someday swapping my Aerovee for a Rotax (when I can afford it). I think that if enough of us request a Rotax mount the factory may produce one.

We have tried that for many years with no luck ....

[garyb]

Hi all,
Who was posting a year ago about using a custom ring mount to convert from an aerovee mount to a rotax mount? Is that you gary?
Thanks chris for always good info posts.
WaiexN143NM
Michael

Check this post out
viewtopic.php?f=60&t=579
bishoff7 was making an adaptor from Aerovee mount to Rotax
Cheers