Aerodis America/CRSS Orion, Rigel and Theta Projects

[Prodr1guez]

Hey team, I finally finished the wing repair on N200AZ. The engine mount is unknown, I'm putting a watercooled car engine in it due to air restrictions etc. The economy hasn't been kind with me and things are super tight at the moment. But I'll keep working on it. By the way, N200AZ will be changed to another N# as that belongs to something else now. Ant advice is welcomed

 

[djfawcett]

If you have an interest, we (airbossaviation.com) can design an engine mount for you. We can also recommend a fabricator.

As a heads up, the mount is by far not the biggest issue. The drive shaft has to be properly sized with the necessary dampening system. Otherwise, your engine will not last very long.

 

[Prodr1guez]

I agree with you and definitely will give them a shout. My fear of long shafts has driven me to look at multiple options like the FK-11 or going all electric. But knowing that someone can help me fabricate the engine mount is awesome. I am getting really close to that stage and I cant wait to see it fly

 

[Prodr1guez]

Ever find engine mounts? Do you have any idea what they are supposed to look like? May sound a little wierd to ask, but there is a not normal engine that was potentially going to end up in that specific airframe that may have them attached. No guarantees, but might be the right stuff……Awesome that someone has gotten this project that wants to make it whole again!

I have an Idea of the engine mount that is suppossed to go with it. I also decided to do away from the lycoming engine as there is no airflow at all in that area. I am going for a watercooled engine and a warp or ivo prop

 

[Ob_seven]

Hi folks

Regarding drive shaft :
1 : needs to properly handle the torque of the engine with long fatigue life. Torque is easily derived from max hp, and for a 4 stroke 4 s cylinder you need to multiply that value by 3. This is the load design .

2 : at max rpm lateral divergence needs to be calculated . Typically not an issue for cf shafts but watchout for steel ones. The Orion shaft is 1966mm long. Diameter 89 wall thickness 1,6mm. Going longer than this is impossible as the lateral limit is about 3000 for steel

3 : torsional resonance needs to be computed. This can easily be done with a holzer model. It is a multidimensional spring mass in rotation. Inertia and torsional stiffness. We tune orion shafts to have torsion first mode at 50hz. 3000 rpm and we cannot go there with lycomings. This means forbiden band at 1500 +-75 as well as 750 and 375 .

4 : kickback at engine start are strictly forbidden. This is what overshresses the shafts

Regarding dampeners : no this is not what is needed. You need to know your resonance frequencies and never fly there. A dampener is a super soft spring that will dramatically lower your resonance frequencies.
You need to measure your engine crankshaft inertia and then measure all inertias with bifilar suspension like the rotax prop measurement method . You need to measure or calculate torsional stiffness of your shafts and critical « soft « parts.

Then apply holzer on that.

Look for an old thread on van’s forum regarding strange Subaru engine wear at 300h. DanH and rve6guy did exchange about all that and you will see how they tuned their reduction unit !

Cheers from the French orion guys.

 

[SorenThePilot]

I agree with you and definitely will give them a shout. My fear of long shafts has driven me to look at multiple options like the FK-11 or going all electric. But knowing that someone can help me fabricate the engine mount is awesome. I am getting really close to that stage and I cant wait to see it fly

Beautiful plane you have there! Refreshing to see it restored, I got a couple photos of it on a trailer at a tire center back in 2019 right after it was bought and was being moved from WA to TX.

 

[Ob_seven]

Hi there.
Here is the link towards the thread on Vans forum that you need to look at about TVs...

Experience with Subaru at 358 Hours - Page 8 - VAF Forums

Page 8-Experience with Subaru at 358 Hours Alternative Engines

vansairforce.net

 

[hesham]

Hi folks

Regarding drive shaft :
1 : needs to properly handle the torque of the engine with long fatigue life. Torque is easily derived from max hp, and for a 4 stroke 4 s cylinder you need to multiply that value by 3. This is the load design .

2 : at max rpm lateral divergence needs to be calculated . Typically not an issue for cf shafts but watchout for steel ones. The Orion shaft is 1966mm long. Diameter 89 wall thickness 1,6mm. Going longer than this is impossible as the lateral limit is about 3000 for steel

3 : torsional resonance needs to be computed. This can easily be done with a holzer model. It is a multidimensional spring mass in rotation. Inertia and torsional stiffness. We tune orion shafts to have torsion first mode at 50hz. 3000 rpm and we cannot go there with lycomings. This means forbiden band at 1500 +-75 as well as 750 and 375 .

4 : kickback at engine start are strictly forbidden. This is what overshresses the shafts

Regarding dampeners : no this is not what is needed. You need to know your resonance frequencies and never fly there. A dampener is a super soft spring that will dramatically lower your resonance frequencies.
You need to measure your engine crankshaft inertia and then measure all inertias with bifilar suspension like the rotax prop measurement method . You need to measure or calculate torsional stiffness of your shafts and critical « soft « parts.

Then apply holzer on that.

Look for an old thread on van’s forum regarding strange Subaru engine wear at 300h. DanH and rve6guy did exchange about all that and you will see how they tuned their reduction unit !

Cheers from the French orion guys.

Nice info,and welcome aboard.