Corvair Engines

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Corvair Engines

Posted: Sat Oct 15, 2011 9:21 am

by chris

After seeing the unusual engine mount on Rhetts post in the sonex build status thread, I investigated his build page to see that he is installing a corvair engine.

Thats something that I have not heard much about, so I thought that a corvair engine thread would make for some good discussion.

How many corvair powered sonex airframes are flying?

What is the typical weight of the engine?

How much horsepower?

Is there any documented performance numbers for the corvair?

Does one build a corvair from an old core or is there a place to purchase a running/kit corvair engine (along the lines of the vw revmaster aerovee great plains engines)?

What are the costs associated with building or buying if possible, a corvair engine?

What are some advantages or disadvantages of building a corvair? I’m guessing cost and possibly power as an advantage with less support/no support from sonex as a disadvantage.

Any other thoughts about using corvair engines?

Re: Corvair Engines

Posted: Sat Oct 15, 2011 1:40 pm

by MichaelFarley56

This is an interesting topic of conversation. I’ll freely admit my knowledge is pretty limited but from what I’ve gathered Sonex does not support the Corvair based mostly on engine weight. I wish I knew how much it weighs but I do know it’s over the 200 lb recommendation by the factory.

That being said, I know that several builders have installed and are very happy with their Corvair engine. Most have claimed that it’s powerful and a very smooth running engine. The cowling requires modification as well as the engine mount.

A lot of these engines are being used on the Zenith 601 XL airframes and seem to be well liked. Back when I was looking at that airframe most Corvair users were happy with their choice.

I also seem to remember the nickname “Cleanex” being used to describe Sonexes with a Corvair… If you google hit you can easily find a lot more info.

Re: Corvair Engines

Posted: Sat Oct 15, 2011 6:42 pm

by rizzz

You can find a lot of info on Sonex/Corvair combinations here:
http://www.flycorvair.com/corvair.html#Sonex

Also, these guys make full Sonex firewall forward kits for their own Corvair conversion engine (incl. Cowling & Mount):
http://www.aeromaxaviation.com/

(BTW: they also make wing tanks for the Sonex)

Re: Corvair Engines

Posted: Sat Oct 15, 2011 8:49 pm

by Andy Walker

MichaelFarley56 wrote:This is an interesting topic of conversation. I’ll freely admit my knowledge is pretty limited but from what I’ve gathered Sonex does not support the Corvair based mostly on engine weight. I wish I knew how much it weighs but I do know it’s over the 200 lb recommendation by the factory.

That’s really the only big strike against the Corvair. I think it’s 210-220lb. I’ve seen various packages giving power from 90-115hp. At those power levels and weights you will not get Jabiru 3300 performace, but it will be much better than the Aerovee and only about $8K or so. I’m too much of a wimp to go against the factory recommendations on FWF weight, but otherwise it looks like a neat option for the more adventurous types.

Re: Corvair Engines

Posted: Thu Dec 22, 2011 12:05 am

by vicdelgado9

Chris, since I am building a Corvair powered Sonex, I have done quite a bit of research myself, but most of it through internet and speaking with the builders.

How many corvair powered sonex airframes are flying? Dan Wesemen, the builder of the original “Cleanex” mentioned there were 7 flying , 2 years ago. I would be willing to guess there is over a dozen easily now, based on turnouts to William Wynne’s Corvair Colleges.

What is the typical weight of the engine? FWF weights can be 210 to 240 lbs. The 3100cc Big Boy being the lightest of the conversions.

How much horsepower? William Wynne states 100 hp for a stock Corvair 2650cc engine. 110hp for the 2850cc, 120hp for the 3100cc Big Boy engine. The 3100CC Big Boy engine is lighter (about 12-15 lbs) than the standard Corvair because of the additional material removed when boring out the block and heads for larger 94mm cylinders.Based on speaking with pilots that have flown the 3100cc Sonex planes, I believe the Corvair may have more available power than the Jabiru, and can certainly run at full power longer than the Jabiru 3300, which is rated for 107 hp and 120hp intermittantly.

Is there any documented performance numbers for the corvair? These are From Dan Weseman’s FlyCleanex.com website:

ALT (AGL) RPM GPS (MPH) FPM GPH
7500 wot 3410 174 6
7500 3350 168 5.8
2500 wot 3460 174
2500 3250 155 (nrml “low alt” cruise) 5.5
200 wot 3540 178 7.2
CLIMB
1000 wot 3050 80 1750
1000 wot 3110 115 1150

Does one build a corvair from an old core or is there a place to purchase a running/kit corvair engine (along the lines of the vw revmaster aerovee great plains engines)? Yes, One needs to locate a core engine to build. The majority of the engine parts in the conversion are new with minimum block, crank, heads and some miscellaneous parts reused. William Wynne sells conversion parts or completely converted engines also.

What are the costs associated with building or buying if possible, a corvair engine? My estimate for building is $6500 to $9500

What are some advantages or disadvantages of building a corvair? I’m guessing cost and possibly power as an advantage with less support/no support from sonex as a disadvantage. Sonex will not provide technical support for the Corvair engine installation, and requests that those planes that do not have one of the 3 approved engines by Sonex, not be registered as under the Sonex name, hence where the name Cleanes, Son of Cleanex, Corvair, Sonair, etc.. comes from. Since many builders call their planes many different names, and since it is not an approved combination, Cleanex type aircraft are like step children and fly and exist under the table so to speak, without a lot of hoorah and fanfare. But there is plenty of support and help for Corvair installations from William Wynne and other builders. My main reason for choosing the Corvair, is that it is a simple and dependable engine that is not stressed in its role as an Aero Conversion engine, and very inexpensive to repair or rebuild, A typical rebuild will be $1000 or less compared to an aircraft engine of several thousand dollars. That fit my philosophy of inexpensive to build and maintain. And Last but not least, it is an American made product. Our economy can use all of the help it can get right now, so it is nice that the dollars spent stay in the USA.

Any other thoughts about using corvair engines? The more and more I have researched and learned about the Corvair, the more I believe I made the right choice for me. This engine was originally designed by Chevrolet to be an aircraft engine, for Aviation contract they were trying to win. When they did not recieve the contract, They decided to use the engine in the automotive market to compete with the mid and rear engine European sports cars. So it, like the VW actually started off as an aircraft engine and was then converted for use in Automobiles.

That is the short version… I could talk about Corvairs for days!! :slight_smile:

Re: Corvair Engines

Posted: Thu Dec 22, 2011 12:15 am

by vicdelgado9

Correction to the engine displacements in the above post:

2850cc is 100hp
3000cc or 3.0liter is 110hp
3100cc is 120hp

Re: Corvair Engines

Posted: Thu Dec 22, 2011 12:23 am

by chris

Thanks for the corvair info Vic. Very helpful. Looking forward to seeing the how the 2 sone…err… I mean corvex or cleanex’s on this site progress. Keep us updated.

Re: Corvair Engines

Posted: Sat Dec 24, 2011 7:54 pm

by rizzz

I just noticed the Aeromax aviation website is not online anymore (http://www.aeromaxaviation.com/). Have they gone out of business? Anybody know anything?

Info about the Aeromax Corvair conversion can still be found on this site though http://www.lightsportaircraftpilot.com/ … index.html

Re: Corvair Engines

Posted: Mon Dec 26, 2011 1:22 am

by vicdelgado9

Yes, Aeromax is out of business, as well as Magnificent Machines, that had the Carbon fiber valve covers and oil pans as well as light weight corvair engine.

Re: Corvair Engines

Posted: Thu Jan 19, 2012 2:17 am

by sonex980

Hi Chris,

I noticed you mentioned the photo of my engine mount and thought I would chime in.

The best place for information regarding the Corvair engine is at www.flycorvair.com, www.flycorvair.net, and www.roysgarage.com

Everything you need to know is at those sites.

Re: Corvair Engines

Posted: Mon Oct 29, 2012 9:55 pm

by structurespilot

Corvair rebuild 007.JPG
Corvair rebuild 007.JPG880×658 227 KB

Corvair rebuild 007.JPG (252.81 KiB) Viewed 8278 times

Corvair rebuild 008.JPG
Corvair rebuild 008.JPG870×652 232 KB

Corvair rebuild 008.JPG (255.96 KiB) Viewed 8278 times

Well here’s my humble Corvair core. I’ve started taking it apart, and it’s going well so far. I know it looks like a pile of scap right now but I have a vision. The cylinders and pistons will be scraped for new VW ( 92mm) ones. The case halves, heads, and crank, are the most inportant parts. If they turn out to be bad, then I will need a new core. So far so good.

Regards, Norm

Re: Corvair Engines

Posted: Tue Oct 30, 2012 2:19 am

by rizzz

Wow, what a project!
Keep us informed, love to see more pictures as you progress.

Re: Corvair Engines

Posted: Tue Oct 30, 2012 10:22 pm

by MichaelFarley56

Wow Norm, you have quite the project there! I keep thinking of Cousin Eddie on the movie Christmas Vacation… “She’s a beaut Clark…”

Where did you find the engine? The more I read about the Corvairs, the more impressed I am by them. I hope all of the important parts are still good for you on this one, and you’ll be able to make it into a good one! Keep us updated on your progress.

Re: Corvair Engines

Posted: Tue Oct 30, 2012 11:07 pm

by rizzz

There are a number of Corvair engine blocks for sale on Barnstormers, some very cheap!
Just search for Corvair on their website.

Re: Corvair Engines

Posted: Wed Oct 31, 2012 4:09 pm

by structurespilot

My brother gave me this core from one of his parts cars. He has two spare engines and more spare cars. I’m quite happy with my choice so far. They are suppose to be very smooth running engines. Anyone remember flying behind the old 172’s with the continental 6 cylinder engines? More cylinders, but smaller in size, makes for a smooth ride.

There a lot of info on the internet but, the best two sites for me are: Flycorvair.net (flycorvair.com), and FlyCleanex.com.

All parts are purchased through these two places, and Clarks Corvairs.

Regards, Norm.

Back to work on my H-Stab, breaks over…

Re: Corvair Engines/Performance

Posted: Sat May 03, 2014 1:49 am

by daleandee

Corvair Engines - Safety Alert

Posted: Sun Aug 10, 2014 3:05 pm

by daleandee

Re: Corvair Engines

Posted: Sun Aug 10, 2014 8:39 pm

by GordonTurner

Hi Dale,

Good catch on the “SB”…for anybody thinking about this engine as a possibility go check out the website (flycorvair.com).

I’m not flying yet but the buildup of my engine with William has been a super positive learning experience for me and my boys. My 15 year old is looking for his own corvair now that he can get running for next year…uh oh, here we go!!!’

Gordon

Re: Corvair Engines

Posted: Sun Aug 10, 2014 10:52 pm

by daleandee

Re: Corvair Engines

Posted: Mon Aug 11, 2014 9:09 am

by GordonTurner

I already suggested the rolling parts cart approach. That got a nasty look…

Re: Corvair Engines

Posted: Fri Sep 26, 2014 6:23 pm

by Lsaircraft

I love the corvair engine but I have always wondered why no one has drilled the heads for dual ignition, seems silly to me that you would go through all the work turning it into an aircraft engine but skip the last step.

Re: Corvair Engines

Posted: Thu Oct 02, 2014 7:56 pm

by Son_of_X

Uhhh…yea…think you need to do some reading here.

http://flycorvair.net/?s=ignition

Re: Corvair Engines

Posted: Fri Oct 03, 2014 11:16 am

by Sonex 772

Lsaircraft wrote:I love the corvair engine but I have always wondered why no one has drilled the heads for dual ignition, seems silly to me that you would go through all the work turning it into an aircraft engine but skip the last step.

I have a Corvair Engine in my Sonex and it does have Dual Ignition as do all the Corvair Engines that are converted to aircraft use, but it still uses the same spark plugs. In the Distributor there are two sets of points, one is the Crans Cams XR-I electronic ignition modual and a set of regular point, each on works independently of there other. If one fails then you have the back up of the second one.. If you have ever seen a Corvair Head you would see that there is not where to drill the head for a second set of plugs..

My engine purrs like a kitten and if you do very thing that is calls for in the manual that come with your engine or ask questions if you are not sure of what you are doing the Corvair Engine is just as reliable as any other engine on the market, plus my Sonex will keep up with any Jab 3300 for more than half the cost..

Mike

Re: Corvair Engines

Posted: Fri Oct 03, 2014 6:02 pm

by daleandee

Re: Corvair College - EAA Video

Posted: Thu Nov 06, 2014 1:42 am

by daleandee

Re: Corvair Engines

Posted: Thu Nov 06, 2014 2:09 pm

by GordonTurner

Hi Dale

I was planning to attend, but work has left me on the west coast. Dang, would love to see your plane and meet you.

Enjoy, Gordon

Re: Corvair Engines

Posted: Thu Nov 06, 2014 7:12 pm

by MichaelFarley56

That’s a really cool video Dale! Thank you for sharing. Did you “graduate” the Corvair college yourself? I’m amazed you can actually take an old case, tear it down, rebuild it, and run it in a few days. I assume you have to have all needed new parts (bearings, cylinders, etc) ordered early and ready to go.

Great idea and it looks like an excellent time!

Re: Corvair Engines

Posted: Thu Nov 06, 2014 9:49 pm

by fastj22

I’m planning on attending the Texas college in February to build my engine for my Pietenpol. I already have the core. Just need guidance, and a decade of build time.

Re: Corvair Engines

Posted: Thu Nov 06, 2014 11:55 pm

by daleandee

Re: Corvair College

Posted: Sun Nov 16, 2014 1:22 am

by daleandee

2

Re: Corvair Engines

Posted: Fri Aug 21, 2015 2:59 pm

by corton

Any builders out there who wouldn’t mind some regular emails/phone calls on building a Corvair? There’s a lot of information out there, and not all of it is centrally organized, so I just need someone who’s BTDT to check with.

As some examples, I’m building a 2700 engine. William Wynne says that the DIY parts should run about $5500, but I’m coming in around $8000 on mine (haven’t spent that yet, but…) Or is that for parts only, and services like rebuilding the heads just adds-on from there? So the question is: how much did you spend on the engine?

How long did it take you to get the heads back from Falcon?

Did you use Dan W for your crank processing? How long did he take?

Did you use all of Williams gold parts?

Thanks;
Carl

(edit - thought I had a signature line)
DFW Area

Re: Corvair Engines

Posted: Fri Aug 21, 2015 3:52 pm

by GordonTurner

Hi Carl,

I’m having a 3.0 built by WW. It’s difficult to address exact costs right now because I’m away from home. I have had Dan W make me one of his new crankshafts and while it took awhile the cost which included machining of the case and new connecting rods seemed fine. My heads are being done now. Same story, took a long time but costs are fine.

Fortunately I started on the engine early. I’m still finishing up the wings and have a ways to go on the fuselage before I’ll need the motor, and I appreciate having the engine costs come in a little here and a little there.

When i ordered the motor mount, Dan cranked it right out.

Gordon

Re: Corvair Engines

Posted: Sat Jan 16, 2016 6:59 pm

by 1flyingyogi

Does anyone have an idea of how many Sonex’s are currently flying with Corvairs?

Looks like most of the Corvairs are from William Wynne, but what do you think about the ones from Azalea Aviation (Bill Clapp)? Are they not as popular just because he got in it later (and so less well known) compared to WW or is there some other reason why builders aren’t using them as much?

I spent a bit of time talking and corresponding with Bill Clapp through email and the logic behind his design sounds good to me. But I’m just a newbie so what do I know. What do you guys think?

Re: Corvair Engines

Posted: Sat Jan 16, 2016 9:15 pm

by samiam

Go to www.flycorvair.net and do a search for Azalea Aviation. You will find out what WW’s thoughts are on this. He is a stalwart when it comes to safety and flying by proven methods, and feels very strongly that the project that he has R&D’ed for the last 25+ years is quite strong. It’s not for everyone though.

Just my two cents. Good luck!

Re: Corvair Engines

Posted: Sat Jan 16, 2016 10:52 pm

by vigilant104

1flyingyogi wrote:I spent a bit of time talking and corresponding with Bill Clapp through email and the logic behind his design sounds good to me. But I’m just a newbie so what do I know. What do you guys think?

I have no direct experience with his products, but Bill is very open and easy to reach, he is a frequent participant on the Homebuilt Airplanes board (http://www.homebuiltairplanes.com), and has a reputation for delivering his products on time and for dealing fairly with people. His demeanor is friendly and supportive: he’s not arrogant, condescending, or rude to newbies trying to find out about Corvair engines. If you haven’t been there already, you might take a look at the Homebuilt Airplanes site and see what he’s written and what others have said about his products.

Be warned–there’s quite a bit of “sniping” between those in the Corvair aircraft engine biz, and it’s often not pretty. You’ll have judge for yourself who the villains and heroes are, but if you are seen traveling between the camps you are likely to wind up with an arrow in your back. It feels like the 8th grade sometimes.

Re: Corvair Engines

Posted: Sun Jan 17, 2016 9:34 am

by 1flyingyogi

vigilant104 wrote:

1flyingyogi wrote:Be warned–there’s quite a bit of “sniping” between those in the Corvair aircraft engine biz, and it’s often not pretty. You’ll have judge for yourself who the villains and heroes are, but if you are seen traveling between the camps you are likely to wind up with an arrow in your back. It feels like the 8th grade sometimes.

Haha. Yes, I totally get that. I’m not at all interested in the drama. I only want to make an informed decision and see what other users experiences are with the products these guys have to offer - not their personalities, although having someone easy to deal with is a plus, but the conflicts and drama they have with each other, I prefer to stay away from.

So on that note, is there anyone else here on the forum with Azalea’s Sypder conversion who would like to share his experience? Or WW’s conversion? I’d like to hear experiences from both, but looking specifically for Bill Clapp’s, since there doesn’t seem to be very many people flying his.

Thanks again.
Brian

Corvair Engines

Posted: Sun Jan 17, 2016 10:00 am

by Sonex1517

Brian

There are certainly a number of Corvair conversions flying, and some of the owners do frequent the forum. I hope one of them will join in and share their experiences.

Robbie Culver
Sonex 1517
Chicagoland
N1517S

Re: Corvair Engines

Posted: Sun Jan 17, 2016 11:07 am

by fastj22

For the past 3 Airventures, I always make time to attend one of WW’s talks. They are more a rival meeting than a seminar. He is a true preacher in the religion of experimental aviation. However, you are either with him or against him. There is no middle ground. And anyone who doesn’t become a true believer, is shunned.

That being said, the Spyder certainly looks nice. But I’m not sure that rear flywheel will mate well with the sonex fuel tray.

Re: Corvair Engines

Posted: Mon Jan 18, 2016 4:26 pm

by mooneybum

CORVAIR ENGINES, well I went to one of WW Corvair forum, there was some one selling all kind of engine parts,
I looked at an dissasembled old engine, asked WW if that man was cosher to buy from and he said yes. I bought
all that stuff and took it to my hanger. Now by closer inspection I found a hole in the crank case and a big bad spot
on the crank shaft. I figured that it may be repairable but better ask WW. Calling for four weeks and e-mailing
him for the same time, I never got an answer. I did not wont to blame any body or my money back, all I was looking
for was advise.
I will never deal with this guy again.

Re: Corvair Engines

Posted: Tue Jan 19, 2016 11:22 pm

by dc75

.

Re: Corvair Engines

Posted: Wed Jan 20, 2016 12:01 pm

by Sonex 772

[quote="dc75. The only downfall to his engines in a sonex is the rear mount starter.[/quote]

What do you think the downfall is on the rear mounted Starter??

I have been running a Bill Clap Corvair in my Sonex for some time now and have 58 hrs on it and it all works great.. I like the fact the every thing is mounted on the rear of the engine, this gives you the opportunity to use a Sonex Cowl..

The WW cowl makes the front of a Sonex not look like a Sonex..

Mike

Re: Corvair Engines

Posted: Wed Jan 20, 2016 1:04 pm

by fastj22

Sonex 772 wrote:[quote="dc75. The only downfall to his engines in a sonex is the rear mount starter.

What do you think the downfall is on the rear mounted Starter??

I have been running a Bill Clap Corvair in my Sonex for some time now and have 58 hrs on it and it all works great.. I like the fact the every thing is mounted on the rear of the engine, this gives you the opportunity to use a Sonex Cowl..

The WW cowl makes the front of a Sonex not look like a Sonex..

Mike[/quote]
Did you have to modify the fuel tray? Seems to me the flywheel would interfere. Did you build your own mount?

Re: Corvair Engines

Posted: Wed Jan 20, 2016 5:52 pm

by dc75

.

Re: Corvair Engines

Posted: Wed Jan 20, 2016 9:44 pm

by Direct C51

The Wesemans and sport performance aviation are now THE one stop shop for a WW Corvair conversion. Contact them and they can work up an invoice for all of the machining including the heads, all the WW Gold parts, the SPA parts, and other miscellaneous parts like the Yanmar Alternator. They have made it very easy. WW is incredibly frustrating to get in contact with. Even with a huge order just waiting to be placed, I can’t get him to return a phone call or answer an email. WW knows a lot about Corvair conversions, but SPA knows how to run a business.

I highly recommend against a rear starter. Having a Sonex cowl is a pretty small reward for such high risk. Rear starters complicate the oil system, they place an unguarded ring gear inches from the fuel filler neck, and most importantly the rear of the Corvair crank just isn’t designed for those loads.

Re: Corvair Engines

Posted: Wed Sep 28, 2016 5:18 pm

by dbdevkc

I would be very interested in learning from anyone with Sonex+Corvair experience about:

  • finished aircraft weight
  • weight and balance
  • gph usage/performance
  • climb rate

Any Waiex using Corvair?

Does someone with experience with the Corvair think there would be any advantages/disadvantages with it in a B model?

Thanks,
Kevin

Re: Corvair Engines

Posted: Thu Sep 29, 2016 8:43 am

by Sonex1517

Kevin

I think you will find Dale Williams more than willing to share his Corvair experience. There are several others that lurk the forum that also fly behind a Corvair.