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Thread: Corvair power?

  1. #1

    Join Date
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    Default Corvair power?

    New to the group. Just got back from OSH with a head full of ideas. Eager to get the OK for the CEO (wife) to begin in earnest... I think having her try on the trike - in the left seat! - at the Kitfox booth may have sealed the deal! She liked it waaay better than her C150.

    Most anyone here knows more about Kifoxes than I, so... Does anyone have any ideas/thoughts/experiences/wisdom regarding a Corvair conversion on a Super Sport? Too heavy?


    Any insight is appreciated,
    ram

  2. #2
    Administrator RandyL's Avatar
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    Default

    I suspect a Corvair would be too heavy. Also, the firewall forward kit from Kitfox is configured with everything you need for a Rotax. If you use another engine you'll need to engineer many of the systems yourself. Imagine having to design and build your own cowl for example.

    General rule of thumb for any customizations you make when building a kit aircraft: multiply the time required for that area by 10x. That said, they are "experimental" aircraft and we all get to pursue the path we prefer.
    Randy Lervold
    TeamKitfox.com Admin Emeritus
    Day job: www.dynonavionics.com

  3. #3

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    Default Maybe too wide, too?

    Randy - Good point. So it got me to wondering if one could use the KF supplied cowl and modify the baffle, but - if my mm to inches conversion is correct - the Corvair may also be too wide at ~28 inches. Keep researchin'...

    Another question - you ordered the QB wing. The KF web site isn't too clear as to what's included over a standard wing?

    BTW - Good job on the mykitfox.com site!

    ram

  4. #4
    Administrator RandyL's Avatar
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    You raise another issue... baffling. the Rotax FWF kit doesn't have any baffling since it has water cooled heads. With a Corvair, or any other air cooled engine, you'd need to come up with baffling to control the cooling airflow. That's a whole black art unto itself!

    On the QB wing, it comes with the skeleton fully assembled, all other tasks still need to be done by the builder. Still, there's lots of ribs that would normally need to be glued in place. Perhaps others can comment on how much time it saves.
    Randy Lervold
    TeamKitfox.com Admin Emeritus
    Day job: www.dynonavionics.com

  5. #5
    Super Moderator Mark's Avatar
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    Hi Ram,

    If there was only one QB item to purchase from all options available, I would recommend the QB Wing. Imagine building a wing to tolerance on sawhorses vs. someone who has built hundreds of them on a factory jig. The amount of time and headaches saved is well worth the reasonable price.

    You will install your tanks, lift strut brackets, and some other associated hardware which is pretty straightforward.
    Mark & Renee Smith
    Boise, ID
    "Build It ..."

  6. #6

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    Default

    ram, I like the idea of hanging a Corvair on the front of the SS. I've been thinking about it for a while and believe it would be a good combination.

    Caveat...most of my opinions about the Corvair engine in an airplane come from William Wynne at www.flycorvair.com. I have spent a lot of time thinking about risk management regarding the Corvair and have some academic opinions but no real experience, except for that '66 Monza I owned several years back. This is the way I see the installation:

    It is lighter than a Lycoming O-235 or O-200 and about 40 lbs heavier than a Rotax 912S. But since the SS can go up to 1550 gross then this is not a problem. It will actually help the cg if you intend on hauling a lot of stuff in the cargo area. If you want to go for an LSA certification then you might want to look at the rotax or Jabiru.

    It is less than half the cost of a Rotax installation.

    William Wynne has engineered a lot of parts to do the coversion. It is not a plug-and-play installation like the Rotax, but it is not starting from scratch either. Things you need to engineer are cooling baffling (which I think you would be able to use the stock cowl), exhaust, intake manifold, mount, and some of the fuel lines. The good thing is that WW has the beginnings of these systems for sale.

    As for the risks involved, the Corvair has suffered several crankshaft breaks in-flight. Simply put, the front crank bearing is not big enough and the crank is not strong enough to absorb the gyroscopic and torsional loads of aerobatic flight, a heavy prop, or a high-horsepower motor. Right now I believe the only proper way to operate a Corvair on a plane is with a light prop, no aerobatics, and limited to 100hp.

    I want to build my Corvair engine with the big bore (3100cc) and get about 125 hp. There are a few options that I need to explore. First, I am waiting for the results of WW's "fifth bearing" design which adds a larger bearing surface. Second, there are a few people that make billett crankshafts, but these might cost-prohibitive.

    My only other reservation is the future of gasoline. If the ignorance of our legislature continues to mandate higher blends of crap-ethanol gasoline then it will not be a viable fuel for aircraft. Will a whole new line of engines that run on flex fuel or heavy fuel (diesel/Jet-A) be available in the future.

    How about a big rubberband? It's easy, cheap, and no problems with ethanol.

  7. #7

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    Default Corvair engine in a kitfox.

    I am building a series 6 Kitfox and have a Corvair engine ready to go. I bought the cowling for the 0200/o235 engines .The Corvair engine will fit very well. My engine weighs 237 lbs. about the same as an 0200.


    bbannon.

  8. #8

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    Default

    Quote Originally Posted by crazyivan View Post
    My only other reservation is the future of gasoline. If the ignorance of our legislature continues to mandate higher blends of crap-ethanol gasoline then it will not be a viable fuel for aircraft. Will a whole new line of engines that run on flex fuel or heavy fuel (diesel/Jet-A) be available in the future.
    Turbodiesels interest me very much. For the reason you mentioned, as well as the fact that I'm a dieselhead. I owned a '99 VW New Beetle turbodiesel that I souped up (and blew up). The current owner, a VW tuner, has the thing running 250 hp AT THE WHEELS, uncorrected, from the 1.9 liters. The torque is beyond imagination. I drove it recently and it scared me.

    But I digress. The current crop of aero diesels are a bit on the heavy side for a Kitfox, but lighter enignes are in the works. Indeed, leaded aviation fuel is a commodity with no future. Refiners sell very little of it, relatively speaking, and they'd love to quit making it altogether. "Diesels" running on Jet A are the future.

    Somebody has a Zenith 701 flying around with a Mercedes A-class 3-cylinder turbodiesel. It has a belt drive, though, which bothers me a lot.

  9. #9
    Senior Member
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    Default Re: Corvair power?

    [quote=crazyivan;254]ram, I like the idea of hanging a Corvair on the front of the SS. I've been thinking about it for a while and believe it would be a good combination.

    Caveat...most of my opinions about the Corvair engine in an airplane come from William Wynne at www.flycorvair.com. I have spent a lot of time thinking about risk management regarding the Corvair and have some academic opinions but no real experience, except for that '66 Monza I owned several years back. This is the way I see the installation:

    It is lighter than a Lycoming O-235 or O-200 and about 40 lbs heavier than a Rotax 912S. But since the SS can go up to 1550 gross then this is not a problem. It will actually help the cg if you intend on hauling a lot of stuff in the cargo area. If you want to go for an LSA certification then you might want to look at the rotax or Jabiru.

    It is less than half the cost of a Rotax installation.

    William Wynne has engineered a lot of parts to do the coversion. It is not a plug-and-play installation like the Rotax, but it is not starting from scratch either. Things you need to engineer are cooling baffling (which I think you would be able to use the stock cowl), exhaust, intake manifold, mount, and some of the fuel lines. The good thing is that WW has the beginnings of these systems for sale.

    As for the risks involved, the Corvair has suffered several crankshaft breaks in-flight. Simply put, the front crank bearing is not big enough and the crank is not strong enough to absorb the gyroscopic and torsional loads of aerobatic flight, a heavy prop, or a high-horsepower motor. Right now I believe the only proper way to operate a Corvair on a plane is with a light prop, no aerobatics, and limited to 100hp.

    I want to build my Corvair engine with the big bore (3100cc) and get about 125 hp. There are a few options that I need to explore. First, I am waiting for the results of WW's "fifth bearing" design which adds a larger bearing surface. Second, there are a few people that make billett crankshafts, but these might cost-prohibitive.
    quote]

    You can actually build one for about $2 - 3K but there is an issue with getting insurance. I have one and in talking with the insurance man, he will not insure a plane with a Corvair engine. I probably need to check again, but that was his answer about 2 years ago.

  10. #10
    Senior Member Slyfox's Avatar
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    Default Re: Corvair power?

    Not to be an A on this one. But it really supprises me how people always try to cheat out on the engine. Remember, you are more than a couple feet in the air when flying. A person should be going after something that is proven for aircraft. I had somebody I know about 3 months ago that had a corvair engine in his aircraft, went down on his first flight, engine quit. He didn't make it.
    steve
    slyfox
    model IV 1200-flying
    912uls
    IVO medium in-flight
    RV7A-flying
    IO-360
    constant speed prop

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