Aeroovee to Rotax mount conversion???

Rotax 912 series discussion.

Re: Aeroovee to Rotax mount conversion???

Postby Bryan Cotton » Sat Sep 24, 2022 12:25 pm

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

The bad way! No way! I've made a lot of washers with a cup saw, or holesaw as we call them over here.

Looks great!
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Re: Aeroovee to Rotax mount conversion???

Postby Kai » Sat Sep 24, 2022 3:19 pm

Yup!

It is just a question of measuring the inner diameter of the coleslaw- sorry: hole saw, and add perhaps a mm or two. That is the washer diameter you will need. You need to make sure that the washer covers ALL of the rubber damper surface. If not you may be sure that the washer will start to dig into the rubber.

Don´t ask how I found out.
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Re: Aeroovee to Rotax mount conversion???

Postby xeriotti » Sat Sep 24, 2022 9:27 pm

Kai wrote:Yup!

It is just a question of measuring the inner diameter of the coleslaw- sorry: hole saw, and add perhaps a mm or two. That is the washer diameter you will need. You need to make sure that the washer covers ALL of the rubber damper surface. If not you may be sure that the washer will start to dig into the rubber.

Don´t ask how I found out.


jajajajaja Ive learned lots of stuff that people shouldnt ask how i did!!! XD

Listen.... Anyone know how is the engine oriented in Rotax equipped Sonex/Waiex? How much compensation for p-factor and attitude This one ended straight ahead (0 de grees laterally) ....and 1.8 de degrees pointed down..
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Re: Aeroovee to Rotax mount conversion???

Postby Kai » Sun Sep 25, 2022 1:59 am

Well,

My guess is purely speculative: nothing at all- straight as a ramrod.

Certainly no angular deviation from the 3 main axis centerlines- especially nothing ´nose down´. The reason is the overly effective barn door flap which tends to stand the plane on its nose on final: there is not enough trim authority to compensate, and you need additional help from the elevator. With a little down angle on the prop and the engine on anything more than low idle, this would certainly aggrevate the situation.

The ones we do up here are all oriented with the prop flange in the same planes as the Jab 33A. Longitudinally this is easier said than done- a lot depends on what dimensions the original engine mount has.

Should the installation check reveal any deviations, this is adjusted with washers.

Thx
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Re: Aeroovee to Rotax mount conversion???

Postby xeriotti » Sun Sep 25, 2022 2:24 pm

And what angle are Aerovees and Jabs pointed???

Im thinking about test flying it...before fitting the cowling... That way if theres any correction to be made i can modify the cowling to perfectly line to the prop cone.
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Re: Aeroovee to Rotax mount conversion???

Postby 13brv3 » Sun Sep 25, 2022 2:32 pm

I wouldn't angle the engine up or down, but I'd certainly allow for some right offset to compensate for the left turning thrust. I left mine straight, and there's a pretty big change in yaw when you add or reduce power. At some point, I'll shim the engine to the right, though I have no clue how much would be needed.

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Re: Aeroovee to Rotax mount conversion???

Postby xeriotti » Sun Sep 25, 2022 7:53 pm

13brv3 wrote:I wouldn't angle the engine up or down, but I'd certainly allow for some right offset to compensate for the left turning thrust. I left mine straight, and there's a pretty big change in yaw when you add or reduce power. At some point, I'll shim the engine to the right, though I have no clue how much would be needed.

Rusty


What the manual says about engine angle? In other aircraft its usually 2 degrees pointing down and maybe 1 or two compensating p-factor....

What are you guys using and what are your results?
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Re: Aeroovee to Rotax mount conversion???

Postby Skippydiesel » Mon Sep 26, 2022 7:42 am

I am sure that I have seen this debate elsewhere - the result "fence sitting" ie about equal numbers for/against, with neither side bringing a scientific/researched/tested argument to sway the reader in either direction.
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Re: Aeroovee to Rotax mount conversion???

Postby xeriotti » Tue Sep 27, 2022 2:18 am

Skippydiesel wrote:I am sure that I have seen this debate elsewhere - the result "fence sitting" ie about equal numbers for/against, with neither side bringing a scientific/researched/tested argument to sway the reader in either direction.


Im flying it without cowling....If it flies striaight and has no weird tendencies when applying or substracting throttle im leaving it as it is and proceed with the cowling.... Unless someone changes my mind along the way XD
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Re: Aeroovee to Rotax mount conversion???

Postby xeriotti » Tue Sep 27, 2022 2:28 am

And some updates... Im rtying to solve my firewall forward. So im starting with what i think are the easier items...

Im fitting a 22ah Gel-AGM Battery... It will be held in place with this box and backplate (firewall is so thin.. the backplate will have welded nuts on it and will be ribeted in place from the inside) The box will be held in place via 5 M6 screws. Aint going nowhere.
Image

And this is my 30 degree oil reservoir mount for the firewall... Also has a reinforcement backplate for the firewall
Image

No aluminum available fast, esasy and cheap.... So im going for stainless if available, otherwise...mild steel and then powdercoating.

Up next I will try to solve the exhaust system... Id love to make a 4 to 1 happen.... Sounds beautifuly disturbing and im sure there is some performance gain in there..
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