Legacy 2.2L with 2 to 1 re-drive.

[Texas Armadillo]

Our Chapter is building a 2 place machine. We have a Legacy 2.2L engine, and are looking to buy a re-drive. We have found a 2 to 1, but we have heard that a 2 to 1 on this engines will set up some harmonics, or some kind of harmful vibration. Has anyone else heard of this, or are you running this set up?

Thanx,
Jeff

[Aussie_Paul]

Jeff, I believe that you need to avoid exact numbers like 2 to 1 or 3 to 1. There are harmonics involved abd can be quite severe.

I have run a lot of ej-22s and the best redrive ratio and prop diameter seems to be 2.25 to 1 and a 68" prop. A 2.6 to 1 and a 76" prop will be more efficient BUT it is more difficult to get CLT without needing a ladder to get into the machine!!!!!!!!!

I hope this helps.

Aussie Paul. :)

[Texas Armadillo]

It helps a lot.

Thank you, Sir!

js

[Aussie_Paul]

....Ernie Boyette is the US agent for the New Zealander Niel Hintz Autoflight gearboxes suited to fit the ej-22. They have the ability to be mounted with the prop below the engine crank which is what you want for a gyro.

Here in Oz I use the 110 hp Hirth box with a locally made adapter. I have over 500 hours on this set up training and all I ever do is change the gearbox oil. See what you can get a Hirth box for over there.

paulbruty@lexicon.net is my personal email if you think you need to go direct.

I hope that this helps Les.

Aussie Paul. :)

[Chopper Reid]

I run a Rotax gearbox,2.6 ratio and 76 inch prop on the back of my 2.2 Suby. I had a NSI with a 2.2 ratio before and the diference between the two ratios is very noticeable. Only thing you have to do with the Rotax gearbox is replace the bottom bearing every 250 /300 hours.