Aeroovee to Rotax mount conversion???

[xeriotti]

Dont worry!!! I changed my mind about flying without a cowling XD.... (Thanks BTW)

No pics of the process yet.... but ive been shaping the cowling today.... im going to use the lower portion of the original cowling provided by Sonex Aircraft.... And will shape te front and upper parts to make room for the 912... Im also going to add some naca vents and ducts to accomplish propper cooling of the water and oil radiators...

[13brv3]

I'm glad to hear that. When making the cowl, try to leave yourself an easy way to rework it later to add some right thrust angle to the engine. I will be shimming my engine to the right eventually to reduce some of the throttle induced yaw. It's not a high priority now though.
Rusty

[xeriotti]

Its really hot over here... And im not a morning persona jaajajaj So im working just a while per day to make this happn...

Recycled the most part from the original Sonex Aircraft cowling.... 75% of the sides and almost all the front and belly... And yes... My propeller cone is enormous and sexy XD


Some paper tape adde to imagine how the new hood will look like



The exhaust sounds amazing.... Cutaway is ready so it doesnt rubs againsssst anything. Will add a little cowl lip for rigidity and improved cooling purposes

[xeriotti]

Ive been playing with packing tape, cardboard and foam....










Im good at molding and ended up beign pretty close to my idea of mean and pointy... But im deffinitely not messing with fiberglass, my friend Diego did his magic....he is a seasoned RC model maker, and he takes part in almost every aircraft project i made that involves composite materials...



A few layers of fiberglass and epoxy resin later.... (4 layers of 160 gram bidirectional and epoxy resin)



Looks fast XD

[xeriotti]

Working a bit more on the cowling :)

[SonexN76ET]

I will endeavor to post more photos soon

[SonexN76ET]

Your cowling is shaping up nicely.

Here is a photo of my cowling as I prepare it for final finish. Perhaps this will give you some further ideas.

Jake

[xeriotti]

Your cowling is shaping up nicely.

Here is a photo of my cowling as I prepare it for final finish. Perhaps this will give you some further ideas.

Jake

Looks great!!!!

How you compare your plane...from the Aerovee to the Rotax 912? Cruise Speed, Max Speed, Climb Performance, Fuel comsumption?

[bishoff7]

Hi all . I am the guy from Downunder that built that engine mount adaptor that fitted straight onto the Aerovee mount which is still on there and still going fine. As would be expected the rubber mounts have had to be replaced several times over the years but that is the only maintenance that has been required . The mount is far from elegant but practical and fairly easy to fabricate and the drawings for it were done from the dimensions provided from the plans from Sonex and the detailed drawings given on the Rotax web site which could be directly imported into a cad program .Regards Bish

(PS) for what its worth my lessons learned with the Rotax is that it is a far more complex engine than the Aerovee and the fine tuning of your cooling systems are a fairly complex to the point of being a real PITA , having some experience in fluid dynamics is definetly an advantage. The Aerovee is much simpler on install and on maintenance and a sweet motor to boot Regards Bish

[Kai]

Í´m speculating several of the previous Sonex engine mounts are suitable for adaption to a 912. The first custom built mount I know of positioned the prop flange of the Rotax in the exact same position as the Aerovee- with the welding jig and all it was a tremendous lot of work: never again! Not to mention the purchased Rotax rubber dampers with associated parts wich cost a small fortune.

My own 912 installation was indeed inspired by the beautiful simplicity of the square tube ring mount designed and built by Bishoff77- however the basis for my conversion was the standard Jab33A mount supplied by Sonex, and the Sonex rubbers for that engine. I theorized that the J33A and the R912 are of roughly the same installed weight, so it was only a question of fabricating adapter plates that would mate the 33A mount to the Rotax standard ring mount. These bars came out looking a little scary- someone on these pages that shall remain unnamed unceremoneously labeled them looking like railway tracks: I can´t say I disagree.

Rubber isolators set #1 are still sitting there, but it is early days yet as there are only 55 hours on the engine-sooner or later they will have to be replaced.

Photos of this installation have previously been posted on these pages, so I won´t bother you with that, but it is safe to say that the cowling provided most of the head scratching, both externally and the cooling bit. I ended up with a slightly redesigned cowling bottom and cooling air outlets over its entire width, as well as the side outlets for the B-series. I must have done something right because I am nowhere near overheating, no matter what I do. Two BMW full flow thermostats peg the coolant temp at 72 centigrades.