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rampilot
08-04-2008, 12:52 PM
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. :D

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

RandyL
08-04-2008, 02:53 PM
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.

rampilot
08-05-2008, 06:22 AM
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

RandyL
08-05-2008, 06:32 AM
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.

Mark
08-05-2008, 07:26 AM
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.

crazyivan
08-07-2008, 08:25 AM
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.

BBannon
09-29-2008, 08:23 PM
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.

mickey
09-30-2008, 07:46 PM
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.

Paul Z
12-27-2008, 07:08 AM
[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 (http://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.

Slyfox
12-27-2008, 09:54 AM
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.

Rodney
01-26-2009, 02:09 PM
Well - lots of guys & gals have gone down behind Continentals and Lycomings and didn't make it either - same thing for Rotecs and almost any other engine you want to name. :(

Just this week we had a guy land his Cessna 150 on a golf course in Dallas after his engine quit. Guy must be a bad golfer too cause he ended up in a sand trap. OK sorry - bad humor. :D

The corvair certainly has had it's problems - but if you follow the history closely, most of the problems have centered around crankshaft issues.

Now with the addition of nitrided cranks and a fifth bearing added to handle gyroscopic propeller loads, this engine is certainly worth consideration.

I'll say this, any time a serious issue has arisen with the Corvair engine, there is a very active group of owners, engineers and builders that have actively addressed the issues head on, and kept the public well informed of their progress and changes.

Not so with Lycoming and Continental. How open have they been with their own crankshaft issues. Just ask Malibu owners if you have any doubts. Here's an AD for you fella - and oh - by the way - it's gonna cost you 30 thousand buck to fix your engine. :mad:

I for one applaud the efforts that have been made to make the corvair engine, and vw engines too for that matter, safe to put in an airplane.

As soon as I sell my current airplane I'll be starting in on a Kitfox - and a corvair engine will certainly be high on my list for consideration. :D

Regards
Rodney Wren

Rodney
02-13-2009, 01:52 PM
Hey - did I kill this thread????????????\

Sure didn't mean to.

I too really like the idea of a Kitfox with a Corvair - especially one with the new 5th bearing and the 4340 cranks that are becoming available.

I've talked to Aeromax and they will build to suit at a fairly reasonable price - especially compared to Lycoming and Rotax.

Anyone else thinking along this line??

Regards
Rodney Wren

Rodney
02-14-2009, 08:37 AM
Well RATS! :(

Anyone in the North Texas/Oklahoma area doing a Kitfox with a Corvair????

I'd love to see one.

Thanks
Rodney

tleed
10-26-2009, 06:55 PM
Looks like I'm going to be something of a pioneer here. I'm planning to hang a Corvair on the front of my Model IV-1200. I did a lot of talking and reading before I went with that combination.

I've been to one of William Wynne's "Corvair Colleges". The info stream there was way too deep to drink all at once. Suffice it to say there is a large support system there. I wound up opting for one of the fifth bearing set-ups with a nitrided crank. I'm not a daredevil.

As to weight, apparently Subie's are pretty heavy and there are a significant number of them that have been hung on the front of a Model IV.

William Wynne has also done a lot in regard to cowling, baffling, engine mounts, intake/exhaust, etc. In fact, I'm carting my frame down to SC in a couple of weeks to have him help me work out the engine mount and an upcoming Corvair College.

Thomas

Dead Roman
12-22-2009, 09:39 PM
William has posted on his site thet he feels the model IV and up would be more than satisfactory for corvair use. I plan to build his 3100cc motor rated at 120hp. Its also the lightest model. Throw in the fact that im gonna build it up as hand prop only any you drop even more weight.

Slyfox
12-23-2009, 04:08 PM
hand prop, why on earth would you want to go threw that garbage for?

Dead Roman
12-23-2009, 05:24 PM
Whats wrong with hand prop? People been doing it for years.

Slyfox
12-23-2009, 06:34 PM
if that's what you want, go for it, not this kid. Oh and what's wrong with it, I love my arms for one.

I know a guy that thought it was cool to have such a plane until one day he started it and it went full throttle, got away from him and ended up in the river after flying by itself a bit.

horsepower
12-23-2009, 10:09 PM
If your wanting to go starterless for the less weight I believe they make a light weight mini starter for Corvairs.I admire your decision to break the mold and go for something a little different than the 912.If you were one of the ones that bought a 912 a few years back then you did well but the price now is out of line in my book.They are a great engine and if money was no object thats what I would have,that being said I have heard good things about the newer Corvairs and the extra bearings make it a true aircraft engine.Get yourself a starter, on a hot day that beast can kick back like a mule. Good luck with the engine. Randy

SkyPirate
12-23-2009, 10:58 PM
Actually I don't blame you either into looking for other power plants ,..that is why I am going to be probably the first to use a 2009 ford 2.0 DOHC engine on an aircraft ,..it's 140 HP and weighs in close to 200 lbs ,.I'm going to build my own manifolds to try and lose some weight ,..I will have to add a PRSU which will add a little weight but also torque along with the weight:) ,,as mentioned in a previous post ,..i can get a ford 2.0 out of a 2008/2009 model focus with 5k miles or less for around $800.00 or less ,..

Chase

jonbakerok
12-25-2009, 04:58 PM
When I went through this exercise I concluded that the corvair was just too heavy, based on the weights I was able to find. Here's the engines I considered:

...............Ramp weight...Lost payload...HP
Lycoming O-23........250......87................118
Corvair O-164.........225......62................100
Continental O-200...215......52................100
Subaru E81............200......37................100
Jabiru 3300cc.........178......15................120
Aerovee VW...........166......3...................80
Rotax 912..............163......0...................80
Jabiru 2200cc.........132.....-31.................85

I got real excited about the Aerovee but after some research I became skeptical about the HP claims. The company wasn't interested in helping with a Kitfox installation, either. Great Plains VW might be an option, though.

Then a used Jab 2200 turned up and ended the debate.

Besides the lost payload I was worried how far forward an extra 60 pounds up front would move the CG. I once considered buying a Model 5 locally that had a Subie up front. It had a huge hunk of lead in the tail to make it balance.

Dead Roman
12-25-2009, 05:32 PM
Subaru installations will never come close to as light as a corvair installation. There is a kitfox with a great plains vw flying. I think the performance is not quite as good as a 503.


also. You guys should be looking into the 0-190 which weighs it around 212 and puts out 120/hp

Pilot4Life
12-25-2009, 07:41 PM
Was that 0-190 power at take-off or continuous power available?

Also, that chart that jonbakerok made up was interesting to see the side-by-side comparison, but remember that the 912s puts out 100hp on take-off and, from what I've understood, 90hp cont. The 912 listed was more than likely the original. Would be great to see some updated information. Hmm...maybe a homework project for myself? I'll do some digging and perhaps come up with an up to date side-by-side! I'll get to it soon enough! Good luck!

Dead Roman
12-25-2009, 08:25 PM
110 continuous at 3000 RPM

120 Climb/peak at 3200 rpm


I think 200 rpm is a fairly arbitrary number that probably wont make a whole lot of difference in engine temps/life. Also these numbers were pulled off an engine with a very restrictive exhaust. Actual numbers are probably going to look more liek 120 continuous, 125-130ish peak.


I am in no way affiliated with william wynne or any of his work on corvair powerplants. He is confident his powerplants will be solid performers on the kitfox IV and higher airframes. I personally think spending the kind of money rotax wants for a 912 on anything other than a radial is insane. Same goes for anything produced by continental/lycoming. I feel like what William is doing with the corvair is going to be revoloutionary for homebuilding.

tleed
12-26-2009, 01:50 PM
I'm with Dead Roman on the weight of the Subie E81 installations. That 200 lbs. isn't close to the final installed weight that it takes to hang that thing on the front of the airplane. I didn't make a chart as nice as jonbakerok's, but when I was working through my hp/weight research, I made certain discoveries.

First, Subie users often omit the weight of the water & radiator & other associated water-cooling apparatus necessary to get that engine on the plane. But no plane will fly w/o it, so you have to count it. And, while I've never heard of a Corvair running on the front of a Model IV, I've heard of several Subie's. Who made up the rule that Subie's can go on the front of Model IV's, but not Corvairs? But, even more curiously, I ran across several Subie's on the front of Model IV's becoming available because their owners were replacing them with something else. So perhaps a Subie really is too heavy. But, see my first note above. They're heavier, installed, than some people want you to think.

Second, the VW installations often include re-drives or mega-aggressive bore/stroke combos. That's more weight, complexity, and/or cost. That said, I looked hard at a VW, but finally went with the Corvair instead.

Third, my Corvair will be well under 225 lbs. and will develop it's max torque & hp in a relatively unstressed condition and at a relatively low rpm. It won't have any water or radiators onboard or re-drives either.

Dead Roman
12-26-2009, 02:35 PM
Another bonus about corvairs is the 120hp they make is made at RPM's welll below what they were built to handle. Very smooth running engines as well. For the kind of light aircraft that most of us tend to build(i mean homebuilders as a whole) it is and absoloutley ideal powerplant. People talk about its TBO being low, it also costs less that a quarter of what it would cost to overhaul an o-200 to overhaul a corvair.

Mnflyer
12-26-2009, 05:07 PM
Hi, is dual ignition available on the corvair engine? That would be the deal beaker for me, I have flown behind a VW, while it ran fine I never loked the single ignition and it was a bear to start when warm/hot and the set up I had was extremely prone to carb icing. I agree 100% that subes are not an engine for the model IV's or any Kitfox as far as I'm concerned they are too heavy.

Dead Roman
12-26-2009, 05:14 PM
you can have everything except dual spark plugs i believe.

SkyPirate
12-26-2009, 07:17 PM
someone that is handy with casting and knows the formula/recipee can take a corvair head and modify it for dual plugs,..getting the recipee right is the trick though.
as for dual ignition,..I have had a couple pistons melt on me ,..dual ignition didnt help me a bit ,..so dual ignition isn't a priority to me,..a good single ignition suits me fine,..just stay on top of it,..9 times out of 10 ,..a single ignition system will give you some sort of a hint that it might be on it's way out,..
and I'm not kicking redundancy :) just my personal preference,..
the ninja approach :) be. . . . . the plane ,..ha ha

Just another good reason why it's good to practice dead stick landings ,..before their is a problem :)

Chase

Mnflyer
12-27-2009, 06:41 AM
Hi Chase, dual ignition will / has nothing to do with preventing piston melt down that would be caused by too low a fuel octane, wrong spark plug heat range or ignition timing or any combination there of. Maybe you can detect ignition failure 9 times out of 10 but iI sure can't and I have experienced mag failure a number of times and believe me had I known before takeoff that a mag was going to fail I'd replaced it before takeoff, now spark plug and ignition wiring problems even ignition timing can generally be sensed prior to total failure.

Personally from my research I think the Corvair engine maybe be a great aircraft engine with the latest mods available for it, it just needs a dual ignition mod to my way of thinking.
And being prepared for off field landings is always a must.

SkyPirate
12-27-2009, 12:05 PM
True Mnflyer ,..but my point was in saying that ,..was that there is only a single piston per cylinder,..as for noticing a possible failure in the ignition system ,..a dual ignition will hide some of the foretold warning signs,..
a hot coil or a coil with a crack will run great until you put it under a load,..not saying all would use an auto ignition system ,..but I;m sure some would,..
I am going to use an auto ignition system on the motor I'm using ,.it's a 2009 ford 2.0 DOHC
it's 140 HP at 212 lbs, motor alone ,..no add on's,..but I plan on building new manifolds to lose some weight,..it will be a learning process,.I'm sure that no one has used this conversion yet.
it will need a reduction unit ,..the power/torque band comes in at 4500 rpm so I won't be turning 5k and up RPMS all the time ,..in the auto ,,it get's 35 mpg,..
I bought a 2009 model car with this motor in it for the purpose of studying it .
The advantages of this motor being that it's of todays technology ,..it is also the motor used on the rally cars and there are already allot of components that they make for this engine to lighten it ,..aluminum harmonic balancer,..aluminum flywheel ,..etc and heavy duty ignition systems,..and it will burn corn fuel all day long :) or alcohol,..aviation fuel etc.

Chase

tleed
12-27-2009, 01:05 PM
So how much does the reduction unit you're going to use weigh for that Ford 2.0? Because if you really want to measure apple-for-apple to the Corvair, that's the figure you need. Comparing the engine weight alone is artificial if/since/because you'll be adding more weight to make it useful in the plane and I won't with my Corvair.

SkyPirate
12-27-2009, 02:07 PM
good point ..the reduction unit will have some weight ,..but ,.. by using the reduction unit I eliminate having to go inside the engine with any machining for thrust plates/bearings ,..the PRSU will have timken bearings so no end loads on the motor,..the only load on the motor will be in the direction it was built for.
I can build a PRSU for this motor and have it weigh in at around 10 lbs or less ..the bearings ,..there are no short cuts,.. they are what they are ,..you can not make them out of any other product besides ( added weight ) steel,.except for ceramic,..the cost of ceramic timken bearings for a PRSU,.. I might as well buy a rotax 912 and be done with it,..this would only be to lose ounces in weight so not justifyable ,..although ceramic bearings are the best of the best,..
So in effect ..1.5 lbs +/- for the lower drive pulley ,.. .75 lbs +/- for upper ..the rest of the weight is in the support system and ..bearing assembly for the upper pulley ,..I won't know the actual weight until I build it,..the crank will support the lower pulley and keep it in line with only side loads applied to it which is what the motor's internal bearings are designed for ..you just need to have ample support for the upper pulley that is subject to omni dirrectional loads ,.the timken bearings are designed for omni dirrectional loads,..which eliminates the need for thrust plates/bearings


oh ,.in case any one was wondering ,..I'll machine the pulley 's out of 6061-0 and them heat treat them to T-6 spec's,..they will be a cog belt pulley


Chase

Dead Roman
12-27-2009, 05:54 PM
Are you using a belt drive?

SkyPirate
12-27-2009, 08:09 PM
Yes a belt drive ..cog belt

Chase