Aeroovee to Rotax mount conversion???

[xeriotti]

That's a lot lighter than I would have guessed. Now for the fun part of adding the engine attachments.
Rusty

Im with other projects on the go... But i have the attachments almost ready... 4 anchor points in the engine and 8 tubes connecting to the adapter plate.... I already have 3 tubes done, when the 4th is ready i might rtack weld it together to resolve the other 4...

Its not fun at all... Takes lots of guessing measures and lucky strikes to make those notches and leghts right!!

[Bryan Cotton]

Nice work! I'm enjoying the fabrication pictures.

It's type 2 fun - where it seems more fun later.

[xeriotti]

Its not a modern art sculpture... Its working alone XD

[xeriotti]

Saturday night special... Took a little more measuring and trial and error than expected at first but with a blend of a little metalworing skill and a ton of luck with tha handmade notched tubes it ended up pretty much perfect...





















Its only tacked in placee, next step is to fully tig weld everything, heat treat, bead blast and powder coat it white :) (aerovee mount is black... i worked so hard to get it right i want it to stand out when cowling is off XD)

[xeriotti]

Its looking good.... almost stained my fingers white to put it there jajajaja

When its totally dry im bolting it to the engine, meanwhile i have to sort other things out...liek the alminum washers for the rubber mounts...

[13brv3]

That certainly looks like it will work. Thanks for all the pictures.
Rusty

[Kai]

Ï can only agree with all the others- an impressive piece of work indeed! The low weight is frankly astounding! My best wishes for all possible final success.

Yet I cannot refrain from pointing out, that there might possibly have been introduced some avoidable structural issues in both this ring mount, and the complete design as a whole.

The first one I already pointed out in an earlier posting in this thread: the missing upper square tube on the Aerovee engine mount as seen on original J33A engine mounts. It must be realized that the R912 is close to identical in weight to the J33A, and that with its reduction gear it produces torque (it torques to the left: RIGHT pedal!!) of a magnitude previously not seen by the upper fuselage angle attach brackets. The decision to omit this square tube stiffener should be made after careful consideration.

The second one is best illustrated by posting a photo of an original R912 ring mount- if one looks closely and compares the two designs, it is easy to see: one upper engine support tube is missing. In addition several of the engine support tubes are just not only butt welded to the front of the ring, but in fact go through it and are also welded at the back.

My two bits.
Thx

[Kai]

Further to my previous posting directly above, I enclose a photo of yet another amateur built Sonex Legacy/R912 engine mount, based on the original Rotax ring. Very clearly the upper square tube cross stiffener is illustrated. Also note that this tube supports a lot of the engine loads.

[xeriotti]

Kai!! we are tuned in the same frecuency!!!

Im definitely going to add that crossbar reinforcement.... Im toing to sandwich sing the already existing mounting points on the waiex where the engine mount meets the aluminum fuselage. Rotax produces lots of thrust and torque... I think its a must.

About the missing tube... My tubes are anchored more widely, forming triangles that will avoid that paralelogramic effect the guys at rotax tried con counter with that angled tube up there.

The thru-tubes is a solution when you dont have enough wall thickness for an optimal weld... In my case, the tubes that connect to the engine are .083in thick 4130, welded to a 1/8" thick plate... The rest of the engine mount isnt as tough...And i dont know of any engine ripped off a sonex to date XD

I painted it white, i will regularly check it but I think it will work fine...


I really appreciate all the knoledge, help and ideas you guys give me... Every small idea or comment is added safety, fun and is what makes experimental aviation so marevelous... Really valuable for me and for every person that reads our lines

[xeriotti]

It fits, and looks neat...


Aluminum washers to contain the rubber dampers... Made the bad way with a 60mm cup saw that gives me 56mm washers...


Drilled the 10mm center to fit the engine mount thats on the plane, bolt it together with an M10 bolt and lathe turned to 50mm OD


Shiny faces flattened and polished by hand.


In no more than 10 minutes with a little help from my dad it was on the airframe.... Surprisingly easy!









Rather Important.... My center hub distance to the ground with the airplane leveled (window at 0 degrees) is 40.35" (102,5cms) Applying the 9" clearance rule, i would be able to fit a 62.7 inch propeller...
Im going to fit 500x5 tyres, and I may have a little less clearance.... But performance is king. A 68" custom made wooden propeller is on its way :)