Feed back...Best engine combo for the Zenith 750?  Neil

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Randall; Most aviation engines IN EXPERIMENTAL AIRCRAFT do not run mufflers. While I'm not intending this response to be comprehensive, I'd venture to say that I'm not aware of any U.S.-based engines that run mufflers. I'm sure there may be some, but unless it comes that way from the factory (perhaps UL or Rotax), Continentals, Lycomings, Corvairs, and I'll even venture to say that Vikings do not come with mufflers. There may be some other nations that REQUIRE muffling, but not here. The relatively low compressions do not create a lot of noise in comparison to prop noise.

As an A&P I spent my career working on various engines. In GA cabin heat usually comes from your muffler shroud. I have flow some Lyc that did not have a muffler and it is impossible with our headphones, The UL and Viking both have mufflers as does the Cont. I prefer the UL muffler system simply because of how it is laid out.

Well, as I stated, I was discussing experimental engines. The Continental *does* have a muffler in a Cessna, but not (usually) on experimentals. Doesn't for a fact on mine, using the Zenith-provided FWF kit. It *does* have shrouds for cabin and carb heat, but they are just around the pipes, not miufflers. My AeroVee VW conversion in my Sonex didn't have mufflers, either. It's probably more a function of the engine supplier for experimentals. Now you've got me thinking... I dunno about the O-200D continental that TCM sells. I would think that it would *not* come with exhaust, simply because there's too many variables WRT installation specifics etc. dealing with cowl exits.

I understand the physics of why some don't have sound suppression but after 12,000 plus flight hours back in the day before hearing protection I don't have much hearing left so I need mufflers

I know what you mean; when I started flying in '78, no headsets and the handheld mic. That plus a few years working in a systems lab with the giant cooling air systems constantly hissing and my hearing is shot, too. Thank goodness for ANR headsets!

Has anyone actually reported on the performance they’re seeing with the Corvair in the 750? I see that a lot of builders have stated their intentions to use the engine and would expect that some are up and flying. One thing that I was questioning was the ability of the engine to oil at the high climb angles that the airframe is capable of.
Any performance reviews of the engine in this airframe would be appreciated.
Thanks in advance, Tim.
I do know that William ran one of his engines in a plane that was tied down at a 23 degree up angle. He put the main wheels up on a stack of concrete blocks that were almost waist high and then tied the tail down to the ground. He then ran the thing at full power for an extended time period, I do not remember exactly how long, but it was a long time. The airframe used in this test was a high wing homebuilt, but not a Zenith. It ran without a hiccup and without any oil starvation.

Yes, there are some Corvair powered 750's out there, but I do not know how many. I am starting a Corvair powered 601XLB.

Since the Corvair weighs about the same as an O-200 and puts out slightly more power, it should match or outperform and O-200 powered version of the plane.
I have seen mention of the 22-23 deg. test but one doesn't have to look very hard to find pictures of the 701 climbing at angles in excess of 30 degrees. I don't expect to have to do this at every take-off but if a guy needs the maximum stol capability it would be nice to know that your engine was getting oil. Might be worth additional modifications to pan and oil pick-up to increase the margins some. I'm sure William would have some input here. Gus flew this engine/airframe combo he might chime in as well.
I attended the Corvair College held near Orlando this spring. I witnessed Dan Weseman & take his WW Corvair- powered Wicked Cleenex doing 90 degree climbs, rolls, loops, and a lot of other manuevers I don't even know the names of, none of which would be done in a 750, at least not intentionally. If the WW Corvair can do that, what would keep it from handling the take-off angle of the 750 and much more? The only possible issue I can think of would be overheating at full throttle low speed climb, & all air-cooled engines must deal with it. Time will tell when the first Corvair powered 750 develops some performance data. WW and his "Corvair Movement" associates/vendors have high quality products and are the most innovative & independent people I have ever met. Going to a Corvair College is well worth the time & money spent, just come prepared to get dirty & learn a lot.
Neil,
First let me say welcome aboard.
Secondly, I think the 750 is a wonderful choice!
Had I not started a 701 already and being in the final throws with a 601, I would have certainly chosen the 750.
No matter I have at least 3 friends who intend on building 750's so I'll have plenty to play with... :)
They also intend to power them with Corvairs......
Any way with regards to your engine choices, I would sincerely encourage you to look into the Corvair.
There are a plethora of Zenith aircraft flying Corvairs.
Mostly 601's but there is a 701 flying and there are several 750s very near flying.
The 750's firewall is the same as the 601 and so the well established 601 installation applies.
If you want to see a video of a 750 running its Corvair in front of my shop, just go to my page and scroll down to my videos.
This airplane belongs to Ron Robeson who is on this list
You might want to contact him and get his feed back.
He could answer any questions about the installation you might have.
All of the aircraft I am building are and will be powered by Corvairs.
I am also building several Corvairs for others.
If you want more information about Corvairs and the aircraft they have flown, you can check out www.flycorvair.com.
William Wynne has been working with Corvairs about 20 years now and he's in FLA also.
And if you want to keep up with what I am up to you can see www.magnificentmachine.com

If you have any questions about Corvairs or their conversion please feel free to call.
I would be happy to talk about Corvairs.
Brady McCormick
360-635-6042

I'm still all over the map regarding an engine choice.  I have been intrigued watchin "Cub Crafters" of Yakima Washington develop a really cool LSA cub model.  They are now using an ECI engine (Lycoming derivative) to get 180HP for takeoff and 80HP continuous up to 12,000 feet.  If the CH750 can handle the weight (245 dry), that seems like a great option for those of us out in the western mountain states where much of our flying will be back country stuff above 5000 MSL.

 

Does anyone know anything about this engine?  Following is an excerpt from the their website...

...CubCrafters worked closely with ECi, of San Antonio, Texas, on the CC340 engine, which is fully certified to ASTM standards for Light Sport Aircraft...the CC340 is a thoroughly modern version of the venerable Lycoming designs...Therefore, any mechanic trained in the repair and maintenance of Lycoming is equally qualified to work on the CC340. Modern updates include dual electronic ignitions (no heavy magnetos) and lightweight accessory 

components. In addition, an innovative cooling plenum more efficiently directs airflow to the cylinders and oil cooler. CubCrafters created a new, less restrictive 4-into-1 exhaust design that weighs just 6.2 pounds (half that of comparable systems). The alternator mount was modified to fit closer to the crankshaft, making the belt shorter and lighter.

The result is an engine that weighs less than 250 pounds, and is rated at 180 horsepower for takeoff and climb, and 80 horsepower for continuous power settings. At cruise power, fuel consumption is as low as five gallons per hour. Used as specified, the engine has a 2,400-hour TBO.

 

Thoughts?

Just to throw another thought into the arena, I just watched a video of Rotec Engineering running a Jabiru 3300 with WATER COOLED HEADS!  Not only did this keep CHT's down it also kept EGT & Oil Temps down, and for those of us who live in cold climates provides a perect cabin heater arrangement.  No probability of shock cooling during a rapid descent either.

 Just something to consider.

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