Anyone contemplating installing the Edge Performance EPeX150i in a Zenith design?  As I understand it, it is a completely overhauled to factory spec 4 cylinder Yamaha engine, 150 hp, weighs no more or even less than a Rotax 914, and under $20K!

There's been a lot of buzz about the Edge Performance engines what with Steve Henry running one at 300 hp for STOL competitions,etc., but I've not seen a single mention about a Zenith application - seems the 150 hp version would be ideal in a STOL 750!

John N750A

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I think one thing that might be a deterrent and why it hasn't happened quite yet or has been slow to enter the field is it doesn't have a FWF kit that comes with, I know a few people are planning on this setup though as they have reached out in regard to making a mount etc. I think even Steve did his own mount, cowling, cooling etc. would like to see what the future holds for it -Alissa

I used to race Porsche 911 race cars in ALMS and Grand Am. A rebuild was $40K+, TBO was 40 hours. The ultimate Race Performance engine might not be what you want in your daily driver. What you do to win a STOL competition at the elite level does not necessarily translate into longevity. 

From what I have heard, it's a well proven, tough and durable snow machine engine.

Agree - we're not talking about the 300+ hp version - "only" 150 hp!  As I understand it, the base engine/EPex150i is just a fuel injected, normally aspirated engine - no turbo, no "big bore," no high-compression, etc.  I think their history in snow machines pretty much proves durability under tortuous conditions!



Seems to me that you are the perfect builder - flyer person to take on this challenge. Yep I agree150 HP would be awesome on a CH750. CH750 get off the ground quick, just need more rate of clime.


I have been researching. Right now I am planning on a Lycoming-320 on my 750Cruzer. The EpeX looks pretty incredible and something I definitely want to learn more. You?

I've been talking to Ray at Kaolin Aviation about a UL520iST (turbo) in my 750SD.  Ray has one in his RV and claims it works very well with no heat issues, etc.  He presently has a 3 blade prop but has a 4 blade Aeromaster on order.

Other than being the most expensive option I'm looking at, it would be an excellent performer and about the same weight as the Titan, etc.

Any thoughts/comments?


The RV is much faster. That means it has available much more cooling air.

Your right Ken - I queried both Ray and the UL factory rep in Belgium about potential heat problems.   When I mentioned my concern due to the low airspeed of the 750, Ray agreed, but pointed out that the cowling on the 750 is significantly larger than his RV thus more air movement in that regard.  I believe  Ray to be the guru for these engines and trust his judgment. 

Belgium also assured me heat would not be a problem because of the unique design of the engine.  But I also believe my 750SD would be the first with this engine.  Clearly I would be the "guinea pig" which makes me nervous, add to that, I'm a neophyte on experimental aircraft.  I also understand originally the engine did not have an intercooler - now I'm told it should have one. 

Obviously I'm on the fence and appreciate input from you folks.



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