William Wynne

"The Corvair Authority"
5000-18 HWY 17 #247
Orange Park, FL 32003

Ask The Authority!

August 2003 Daily Question & Answers

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November-December 2003 Q & A Page

October 2003 Q & A Page

September 2003 Q & A Page

July 2003 Q & A Page

January-June 2003 Q & A Page

2002 Q & A Page

then by all means e-mail William at WilliamTCA@aol.com. Thank you.

Subj: Front Starter Kit Specs
Date: 8/31/03


A number of people have asked questions about how the Front Starter components are assembled. I've added several photographs, a description and instructions to the Online Catalog of Products from TCA at a special Front Starter Kit Link. Also, all components of the Front Starter System are now listed with links to descriptions and pictures at the Online Catalog at www.FlyCorvair.com.
Thank you.

Subj: Low Profile Front Starter and Ring Gear
Date: 8/30/03

William, what is the smallest diameter ring gear and starter combination that can be had for the lowest view over a close fitting cowling? How much more complicated is it to go to a rear ring gear set to get the lowest view over the nose? Sorry to have missed your outing last Saturday.

Sam Sayer, Zephyrhills, Fla., Karibird37@msn.com
Reply from WW:
The Corvair can use a 10.5" ring gear in the front. Putting the starter on the back of the motor requires modifying the oil system and changing the location of the filter and cooler. This presents a significant amount of complexity which many people do not wish to introduce to the motor. The above photo is a view of my current low profile front starter. You can see more photos at the eBay auction of the 100hp Corvair Conversion I built - but the site is only up until the auction ends Sept. 4. I'm working on a starter nose which will further reduce the current height by 3/4". But I have the setup in the photos available right now, and it requires no oil system modifications.

Subj: PIET - Road Trip
Date: 8/29/03

Had a fun weekend, especially at your place. Can't wait to build up these 6 engines. I am sending you a UPS package, but can't send to a PO Box. Do you have a shipping address?

Did you look at the three engines you got a call about? If you are not going to buy them, are they avaialble? We still need three more. More Later,
Barry Davis, Pietenpol, Georgia, bed@mindspring.com

Each of the six guys from Georgia in the photo above is building a Corvair powered Pietenpol. Look for their story in the next issue of The Corvair Flyer newsletter. We'll be mailing these in early Fall, so be sure to subscribe or renew now.
Reply from WW:
We had a great time also. Our hangar address is 210-11 Cessna Blvd., Port Orange, FL 32128.
There were actually four motors there, and I bought them all. They had been outside for a long time and were really only good for miscellaneous parts. At $60 for all four, the price was right. Keep looking up in Georgia; you're bound to find more with a little work. If anybody in the Atlanta area knows of a source, please e-mail Barry directly.

Subj: My Corvair engine runs for the first time
Date: 8/28/03

Add me to your list of having a running Corvair engine. Attached is a picture of my corvair engine running for the first time on my Pietenpol fuselage. Hope to have the plane finished later this fall. Thanks,

P.F. Beck, Pietenpol, Barnwell, S.C., pfbeck@barnwellsc.com
Reply from WW:
Congratulations! I'm sure it's a proud moment for you. The pictures you've shown us all along have always displayed good craftsmanship and work. I'm sure the engine will reward you with many happy hours of flying. Keep us posted.

Subj: Which Engine
Date: 8/27/03

I received your Conversion Manual today and I can't wait to get started. I will get the one page Registration and Liability Statement sent out here in the next day or two. A little busy here with the forest fires going on here and I have 2 flight crews in my guard unit out fighting them.

I might have jumped the gun, but before receiving your Manual, I purchased 2 Corvair engines. Granted I might have paid more than I should, but I have 2 engines! I just want to get a clarification on the engines I do have. The last 2 digits on the serial numbers I have are YM and YN. These are the 110 hp and are 1964, correct? Are these the engines with the cylinder heads I should be concerned with and will these engines work for my application?
I am currently starting my KR-2S (modified) project, after being away for close to a year being deployed to Afghanistan, so coming across these engines has sparked my interest in building again, plus after selling one of our vehicles and the wife giving me 75% of the money for the sale to go towards my KR project. Any advice will be greatly appreciated, since I have never taken apart a piston engine before. Thanks in advance.
John E., KR-2S, Independence, Ore., jesch@earthlink.net
Reply from WW:
You may have jumped the gun. Both YM and YN engines could be either 164cid or 145cid. The only way to tell for sure is to remove the top cover, rotate the crank and look for the 1/2" tall numbers that read 8409. If the crank says 5607, you have 145cid engines. If you send me the number on your cylinder heads, I'll be able to give you more specific information about them. If it turns out that these are 145cids, a good source for you for a 164cid core would be The Corvair Underground. My Oregon geography isn't good enough to say how far apart the two of you are, but he certainly would be able to provide you with the correct core.
In either case, keep building. We're glad to have you back from Afghanistan, and it's good to hear that you have a very understanding spouse. Your enthusiasm and her support is the proven combination behind many a successful airplane project.

Subj: Where to Buy Motor Mount Bushings
Date: 8/26/03

Gettting ready to mount the Corvair to a copy of Your Pietenpol mounts. Can You give me an idea of where to get those neoprene bushings for the mount isolation? My local car parts guys say there are many different types. Thanks,

Steve, Elma, Wash., srs1@techline.com
Reply from WW:
Above is a photo of the sway bar bushings we use, Energy Suspension Part No. 9.8105RC. They're available from our local Auto Zone. If anyone has trouble getting a set, send $20 payable to William Wynne, P.O. Box 290802, Port Orange, FL 32129-0802. This will cover mailing you a set in the U.S.

Subj: Suggestions for next Manual revisions
Date: 8/25/03

Hey William, I had another suggestion, this time for your next revision of the Manual. (And by the way, this last Manual is a vast improvement over the first one. Great job!)

Picture this scenario: My hangar is a 50 minute drive from my house. So I drive out to the hangar to work on something, and when I get halfway into a procedure (whether working on the engine or on the airframe), I discover I am missing a particular size bolt or a particular lube or tool or something. Murphy's law says it will be something I cannot get at the Chief Auto Parts, but needed to have ordered last week from Larry's or Clark's or something.

It would improve the plans immensely if, for each of the chapters (Disassembly, Case Assembly, Rod, Piston, and Cylinder Assembly, Head Assembly, etc. etc. etc.), you had a list of tools required, parts required and materials required. That way, a builder doesn't get started on a particular procedure only to discover halfway through that he doesn't have a particular item that is required. He can make sure he has ordered all the parts and expendables and has all the necessary tools for that procedure.

I know you aren't trying to replace the Corvair Service Manual, but even for the procedures you do cover, it sure would be nice to have that list in one place, easily digested, at the beginning of each chapter. It would be especially handy for those of us who are doing this for the first time, and have to basically go out and buy every bottle of anti-seize, every can of spray paint, every can of STP, every valve compressor, etc. Thanks,

Dave Morris, Dragonfly, Bedford, Texas, Dave@davemorris.com
Reply from WW:
Your suggestion is a point well taken. I am getting closer to this ideal with my Engine Assembly Videotape Series, which helps people visualize what they'll need for engine assembly. One of the things I've worked on before, which I think would be most useful to builders, in addition to what you've said, is a flowchart on the sequence of building an engine. I saw one of these done for the Sonex aircraft by the factory and it was very, very good. I'll have to put some more time into developing one of these for the Corvair. I'll keep your suggestion in mind as well and put it to work when I can.

Subj: How many passengers?
Date: 8/24/03

Hello! First of all what an impressive engine you have. I'm new in the homebuilder aircraft. I don't have any experience. I'm just wondering: If I built my own plane, can I use multi-engine plane using your engine and how many passengers you think can lift? Thank you.

Leo Pestano, AandL121699@aol.com
Reply from WW:
Thank you for your compliments on the motor. Most single engine Corvair powered planes are two-seaters. A small percentage are single-seaters, and I do not know of any which have flown three or four passengers yet. There are at least five people working on twin engine Corvair powered planes. Four of these are two-seaters. But the sky's the limit when it comes to how many engines could lift how many people. It's easy to imagine a tri-motor that would lift six people, or a four-engine airplane which would carry eight. If you're interested in designing an airplane, the best place to start is with John Roncz's Sport Aviation articles.

Subj: Hypereutectic pistons
Date: 8/23/03

Hello, this is Ted Phillips. I haven't wrote you for awhile partially because of my busy schedule at work and my Corvair re-build! Getting ready to fire my baby up hopefully within the next 30 days. This is a very proud and exciting stage of my plane build. The reason I am writing you (besides catching up) is I feel that as a Manual owner I should inform you of the one deviation I have made from your Manual. I just know that I'm going to get an ass chewing for this, but I have used Clark's Hi-Tech pistons in my engine. The reason for this decision is based on the fact that during the past winter I was told by Clark's that forged pistons were not available and may never be available again! I felt at the time that I only had one way to go, now I know that forged are available but I am wanting to use the pistons I have installed. I know there are detonation concerns with the Hi-Tech pistons, but I thought to manage the risk I would slightly retard the timing and only use 100LL fuel. Do you think these precautions would be adequate ? I know that you are no fan of eutectic (sp) pistons but they must be better than cast, correct? Let me know your thoughts. If you think it is a very poor decision for me to use them I will defer to your judgement and save for the forged pistons. Thanks for your time,

Ted Phillips, GN-1, Chariton, Iowa, tedanddj@mchsi.com
Reply from WW:
You will not get an ass chewing from me. Although I grew up in a U.S. military family, I believe it's a myth that military fathers teach their sons how to deliver first class ass chewings. All you'll get from me is the benefit of my knowledge and wise counsel. The decisions, as always, are all yours.
Hypereutectic pistons are cast pistons. There are only three ways to make pistons: forge them, machine them from a billet, or cast them. A hypereutectic piston is a special version of a cast piston. While they're better than original cast pistons, they're still substandard to forged pistons for flight purposes. I cannot recommend that you fly hypereutectic pistons because I've never flown them myself. But, I do believe you could fly them on 100ll with reduced timing and careful attention to CHT, etc. But this is far from a ringing endorsement or a blanket approval. Now that the TRW pistons are back in stock, you always have the option of changing the ones in your motor out for forged pistons. BTW, I'm sure that TRW pistons are cheaper than hypereutectics. I don't think you'd have the same margin of safety with hypereutectics that you do with forged. The decision is yours to make.

Subj: Skystar Series 7
Date: 8/22/03

Your feedback service is one of the best I've seen. Answering all these questions would drive me nuts, especially the redundant ones.-- Here's another one. Will the Corvair engine work in the Kitfox Series 7 by Skystar? If so, can we get the 125Hp I'd like to run?

May God continue to bless you with an abundance of patience :-)

Russ, rspmaggio@msn.com
Reply from WW:
A 3,100cc Corvair motor will deliver the kind of power you're expecting, and is among the lowest weight engines in this power category. But of course the biggest advantage would be the fact that such a motor could be built for about $4,000 in parts and a satisfying investment in time.

Subj: 65 110 RB engine
Date: 8/21/03

Hi. Is a '65 110 engine with an RB code suitable for conversion? It is not listed in your Manual one way or the other, but the Corvair Underground book lists it as a "manual trans" the same as RA, another code you do not recommend. Am I to assume it has the same low compression heads?

Max Marshall, Manual #5615, byteajoern@webtv.net
Reply from WW:
The reason why RB letter coded engines aren't in the Conversion Manual is that they're 140hp 4-carburetor engines. However, if you have the bottom half of one of these engines, it is perfectly suitable for conversion to a flight engine following the practices outlined in the Manual. You will just need a set of acceptable cylinder heads. Likewise, an RA motor can always have the bottom end used, but the cylinder heads have to be verified to ensure they are correct. Many RAs came with cylinder heads which end in the digits 0708 - these are not acceptable heads, but they interchange with plenty of other sets that are.

Subj: Corvair Jugs
Date: 8/20/03

Just got my jugs back from Clark's; they were able to hone them out and keep them stock. I also ordered a set of long skirt pistons (they only have about 7 pistons left) and I'm awaiting the arrival of my Safety Shaft that I ordered from you a couple of days ago to get my crank tapped. Before I bore you with my happiness, I was wanting to know how much it would cost me for you to make me an engine mount for my KR2S and what information you would need to make it? I'm making it a taildragger.

Last thing: The gentleman from Indiana who was at Sun 'N Fun when I had my case there and we removed the studs, I think his last name was Hudson. Do you have a good e-mail address on him? I would like to see his finished product. Thanks for all you and Grace and the bunch do for all of us...

Bob Glidden, KR2S N181FW, glidden@ccrtc.com
Reply from WW:
There's a picture of Larry Hudson, his son Cody and the motor on display at Brodhead at the News from The Corvair Authority page on www.FlyCorvair.com. The Hudsons did a very nice job on their engine. Larry's e-mail address is indyannie_1999@yahoo.com.
I have a jig to make motor mounts for the KR2 and KR2S. As long as your fuselage has a firewall with the same vertical dimensions as the plans, my mount will work with it. The taildragger version is $450 + S&H. The tricycle gear version costs $500 + S&H.

Subj: I'm interested in converting
Date: 8/19/03

I apologize if the answers are in your Manual, but these questions come to my mind when trying to decide to have a go at building an engine based on your Manual.

  • I am technically savvy but own no specialized equipment. What investment in tools is required to be able to do a Corvair engine conversion?
  • Does your Manual start off with some guidelines on what engine to start with? It seems one must pay attention to serial number or model/year in order to have a successful conversion.
  • The 120 HP engine has a larger bore. Is there any info on how that is obtained? Is the standard engine bored out (seems like a lot of metal has to go) or do you purchase new cylinders/heads? Where does one get pistons? I assume the larger bore can work with the regular valves because the lower rpm (compared to automotive use) gives the engine enough time to suck the extra air in?
  • JP, jspeyart@pi.net
    Reply from WW:
    The majority of my customers are first time engine builders. The engine does not require any special tools. Perhaps a $30 beam type torque wrench from Sears is the only thing beyond wrenches and sockets. It certainly doesn't require a lathe, milling machine or anything like that.
    The Conversion Manual contains all the information you need to know about how to choose an engine: all the casting, stamping numbers, etc. It's available for $59 in the U.S., and $74 for international orders, including Canada, payable by check or money order in US Dollars to William Wynne, P.O. Box 290802, Port Orange, FL 32129-0802, or by credit card via PayPal at the www.FlyCorvair.com Online Catalog.
    More info is in the Manual, but in a nutshell, the 120hp engine is made by putting 94mm VW cylinders and pistons on the Corvair motor. The machine work required is provided at a very modest cost by the man who offers the kit to do this modification. Your assumption about valve sizing is quite correct, also.

    Subj: Candidate Engine
    Date: 8/18/03

    I've run across another candidate engine through a member of a Corvair club. The owner has sent me a couple of photos that I was hoping you would look at and render your opinion. The seller says it's a 1967 110 HP engine. He acquired it from someone in Georgia and has had it in storage for the past 12 years. Prior to that I have no history. He claims the crank turns freely and that the matching heads are #3878566. Asking price is $150.00 OBO. I notice it does not have the Harmonic Balancer. I am suspicious about the block serial number. It almost appears as it has been re-stamped and that the original numbers are barely noticeable just underneath the current numbers. Just my imagination? I intend to look at it next week and will ask to pull the top cover off so I can inspect the crank. Any comments or advice is always appreciated, Thanks for your time,

    Ron Franck, franck@geneseo.net
    Reply from WW:
    Your plan to take off the top cover and look for 8409 on the crank is a good one. Judging from your information, I suspect the motor is a 1967 110hp. Some of these engines did not have balancers from the factory. I owned a 1967 Monza with this exact engine; it had never been touched when I got it, and yet it had no balancer. GM did some odd things the last three years of production. Let us know how it turns out.

    Subj: Preceptor for Corvair
    Date: 8/17/03

    I have gone thru your list & haven't seen anyone ask this question: Has anyone tried a Corvair in a Preceptor Pup (2 place)?

    Doug Baird, DBaird@barroncollier.com
    Reply from WW:
    I do not believe anybody has done that particular combination yet. I remember that Ultrapups were equipped with full VW engines, but I have no knowledge of what the upper limit of weight or hp is for your bird. The Corvair would certainly have enough power for a very impressive installation if the engine met the airframe's design specs.

    Subj: Turbo Corvair
    Date: 8/16/03

    For several months, I've eagerly awaited your article on turboing the Corvair to appear in the Summer issue of The Corvair Flyer. This is of very great interest to me, and I am sure, to many others. What happened? I have no doubt at all that your plate is very full; however, please let me and others know what the status of your turbo project is. Even preliminary information would be much appreciated. Thanks,

    G. Andris Vaskis, Westminster, Md., vaskis@gte.net
    Reply from WW:
    Yes, you're quite correct that the plate is very full. The turbo motor is essentially done. The work was interrupted by Oshkosh, but we are back on track. We have an airframe lined up to fly it on in the Fall after we run it on the test stand. I'm not sure, but we may get it running on the test stand before we send out the next Corvair Flyer newsletter. Be assured that it's of a personal interest for me to get it done, and that there are no technical difficulties standing between me and success, just a matter of getting a few more hours in here and there to get the engine ready for the stand.

    Subj: 88mm VW pistons/cylinders
    Date: 8/15/03

    Hi William:

    I have reported to my group (3 builders) our meeting at OSH. All the information you gave me was shared with them.

    If you remember, I told you that one of our buddies does want to use the VW 88mm cylinder-piston produced down here by Mahle. Although I respect him in this regard, I'm trying to talk him away from this approach because I think this will represent messing too much with the engine by introducing non-original parts in it. Nevertheless, I told him I would contact you in order to know exactly what would be involved in this.

  • The 88mm pistons would require him to rebore the case?
  • You told me the VW piston pins do not match the bore in the rod, and that the rod should be re-bored. Is this very specialized work, or something a good machinist would do?
  • Is there any other work to be done in the rod beyond that?
  • I suppose some work has to be done in the heads also to accommodate the new dimensions. Is that so?

    Any other thoughts? Best Regards,

  • Oswaldo, KR2, Rio, Brazil
    Reply from WW:
    The 88mm VW pistons and cylinders require no machine work to the case or the heads. Only the 94mm cylinders do. I consulted with Jeff at SC Performance to make sure that the 88mms would be dimensionally identical to the Corvair motor in height, etc., to make the engine a bolt together kit. If your friend wants to use the 88mm combination, Jeff will redo the rods to the VW pin size for $50. This is in addition to his regular $200 for rebuilt rods. He also has the $300 rod set which has polished beams. There are valid reasons to be attracted to both the stock pistons and the 88s. Neither one changes the fact that the conversion is a very simple one.

    Subj: New inquizator
    Date: 8/14/03

    Hi William. Until I saw the Corvair conversion at the Great Plains booth at AirVenture this year, I thought the AeroVee was the best value on earth. Now I know that's still true up to 80HP. But the Corvair looks like a very serious engine up to 120HP. At that HP, I'm wondering about altitude. Did I read that you're investigating turbo-normalizing the Corvair? Seems like a Q2 or the new Vision2 could really redefine the envelope if they could get above weather at speed. Please let me know what you're up to w/turbo.

    Joe Tocci, EAA Chapter 2, Fort Wayne, Ind., chairman@smdfund.org
    Reply from WW:
    Thank you for your nice e-mail. A few clarifications are in order. Great Plains is the VW outfit run by our friend Steve Bennett. He has nothing to do with Corvairs. You probably saw the Corvair motor on display at the Contact! magazine booth, around the corner from Steve. It's easy to get sensory overload at The Big O.
    My turbo engine is almost ready to run, and we'll post more information on the Web site soon. It's actually not turbo normalizing, but rather a turbo boost system. And its performance will decay at altitude. Turbo normalizing requires in-flight adjustable props. My intention is to come up with a very simple system that will retain 100hp at 10,000 feet. A Q2 does not have room under the cowl for a turbo Corvair motor, but you're quite right that a Vision EX is a good match. We'll keep you posted with a synopsis at the News from The Corvair Authority page on www.FlyCorvair.com, and also in greater depth in The Corvair Flyer newsletter.

    Subj: Head Studs
    Date: 8/13/03

    William & Grace,

    It was a thrill to meet you at the Contact! magazine booth and to participate in your engine seminar at Oshkosh. I have not yet contacted Clark's about the dragging OT-10 cam, but will do so tomorrow morning. I need seven (7) upper studs and two (2) lower studs. All of the case threads look good except for two, which have two partially broken threads. Would you confirm that ANY sign of broken threads require helicoil? In a couple of months, I will be needing a distributor rebuild and exhaust stubs.

    Joseph Snow, Brookville, Ohio, 1flashq@ameritech.net
    Reply from WW:
    It was great to meet you at Oshkosh as well. Yes, any sign of broken threads requires a helicoil. Please let us know if you still need the studs. I have used studs in good condition for $4 each payable by check or money order to William Wynne, P.O. Box 290802, Port Orange, FL 32129-0802. This includes the S&H in the U.S.

    Subj: Which Corvair Engines?
    Date: 8/12/03

    Hello, I attended your seminar at Oshkosh (I was the guy with his young son - in case you remember) and was very interested. You said there was some group that sold engines as opposed to finding one in a junkyard. What is their Web address? I just bought a partially completed KR2S kit and although I won't need a motor for a while, I will eventually need one and I want to start learning about it. When the time comes, I fully intend to take you up on your offer and come to your place for a class. Anyway, hopefully we can work together in the future. Thanks.

    Ray, KR2S, ray_pilot@yahoo.com
    Reply from WW:
    The Corvair Society of America, www.corvair.org, is who you're looking for. If you do not already have my Conversion Manual, I highly suggest you get it before acquiring a core motor. Every week, somebody buys the motor first, then tells me they spent too much money acquiring the wrong motor. All the part numbers, castings and stampings for the correct motors, along with how we evaluate them, are contained in the Manual. The Manual costs $59 in the U.S., $74 for international orders, including Canada. You can either send a check or money order payable in U.S. Dollars to William Wynne, P.O. Box 290802, Port Orange, FL 32129-0802, or pay for the Manual by credit card via PayPal at the FlyCorvair.com Online Catalog.

    Subj: VW 88mm pistons/cylinders
    Date: 8/11/03

    At AirVenture, you mentioned that, given the dearth of forged TRW pistons, the VW 88mm pistons make an attractive alternative to the forged stock pistons/cylinders, particularly as regards their lower weight. I can find no reference to this substitution in the Manual, and would appreciate it if you could provide me with the details, e.g., part numbers, possible sources, modifications needed to the sheet metal flashings, etc. Perhaps you could put this in a mailer as an "addendum" to your Manual, or a column in your Corvair Flyer newsletter (which I just subscribed to, so I apologize if you've already done that), or in your Q&A column.

    Don Lawrence, Los Angeles, Calif., don.lawrence@comcast.net
    Reply from WW:
    The TRW pistons are now in stock at Larry's Corvair Parts (phone # in your Conversion Manual). If you're still interested in the VW pistons and cylinders, the only source that I deal with on these kits is SC Performance. As stated in the Manual, Bob Sutcliffe developed these conversions. Bob has since sold his business to the very capable Jeff Ballard in Ventura, Calif. His phone number is 805 644-0006. Specific information about piston and cylinder combinations was covered in The Corvair Flyer just before you subscribed. New subscribers can obtain all the back issues as a collection for $10 in the U.S., $15 for international orders, including CANADA, payable only by check or money order for U.S. Dollars to William Wynne, P.O. Box 290802, Port Orange, FL 32129-0802.
    My Engine Assembly Video Part II, which will be available next month, has good visual comparisons of all piston/cylinder combinations for Corvair flight engines. Our friend Merrill Isaacson, aka SkyManta, a video wizard, is in final editing on these now. He is the production talent behind my other videos, as well. Look for Part II coming soon to the Online Catalog of Parts Available from The Corvair Authority.

    Subj: Sonerai Pics
    Date: 8/10/03

    Here are some better pictures of the Sonerai. About 60 hours now.

    Glen David, Indiana, propellerprecision@hotmail.com

    Reply from WW:
    Congratulations. The aircraft looks excellent. Please send us flight data when you get a chance.

    Subj: Upside Down Vair
    Date: 8/9/03

    Will the Vair fly inverted? Just in case my bird wanted to go inverted with me in it that is?

    John Foreman, Sonex #564, jwf3@daimlerchrysler.com
    Reply from WW:
    There's two ways to fly inverted: pulling positive Gs, such as the top of a loop, and true inverted flight, such as flying upside down in level flight. A Corvair motor, like all other aircraft engines, can do the first. In a maneuver like this, the engine and systems have no idea they're inverted in relation to the ground. In the second situation, you need inverted fuel and oil systems. 99% of aircraft engines, including certified engines, cannot do this. Only aerobatic airplanes like Pitts biplanes and Decathlons have oil systems which function with the airplane inverted. Having done a small amount of flying like this, I can assure you that the weak link is the pilot. Very few people are qualified to fly outside maneuvers and it takes a lot of training and physical strength to be safe and proficient.

    Subj: Thrust bearing
    Date: 8/8/03

    I attended your forum at Oshkosh and I must say I was impressed with your enthusiasm and dedication. I am unwinding from my trip as I expect you are, so I will try to phrase a yes or no question. I raised the question at your forum and you gave a good answer. A little fog has now settled but I think you said the thrust is taken at the opposite end of the crank from the prop hub. Are there any future plans to attach the prop to the transmission end?

    Danny, dannyjoe@insightbb.com
    Reply from WW:
    Good to hear from you. We just got back last night. We had a very good trip and really enjoyed sharing what we know with people who can use it. This is what it is all about. The thrust bearing is on the dirstibutor end of the Corvair. This is at the back bumper in the car, or a firewall in the plane. The Corvair is and has always been driven off the transmission end of the engine.

    Subj: Zenair twin, 100ll
    Date: 8/7/03

    I greatly enjoyed my visit to your Web site. The information put forth was very informative and rang of real world experience. I currently own a '66 Cherokee 180 C, but have the homebuilt bug biting me on the butt. I am trying to decide what airplane/engine I want to build/use and I appreciate the information. I owned a '65 Corvair Monza as a teenager and have always regretted selling it. Spent a lot of money at Clark's....

    I have been waiting on Zenith to develop the 620 twin. They are recommending Jabiru engines but I was thinking either Suby or Corvair. Your words of wisdom have been helpful. Do you believe that there will be any issues with the engine when 100LL is phased out in a few years? Thanks,
    Ronnie Jones, jones_rl@sbcglobal.net
    Reply from WW:
    I spent a lot of time with the Heinz family at Oshkosh. They're having a lot of success with the 601XL and expect it to be a major player in the pending Sport Pilot category. Their twin might be a lower priority project these days. I saw the plane in person several years ago, and it was very interesting. I'm not sure it was intended for engines any heavier than the feathery light Jabiru 80hp.
    I've operated the Corvair motor on both 100ll and auto gas. It works on either. Specific details of operational settings for both fuels are contained in my Conversion Manual, available at the Online Catalog.

    Subj: Zodiac 601 Mount
    Date: 8/6/03

    I saw in your answer to Neil Hulin's e-mail on the "Ask The Authority!" page that the 601 is one of the best candidates for your upcoming turbo installation. I am seriously considering matching my future Corvair engine up with a Zodiac XL. Will your install be on an XL? If not, which 601? Also, tell me more about your "turbo" engine. Thanks,

    Gary Kaplan, Zodiac 601, Mount Juliet, Tenn., Kaplan@qualityind.com
    Reply from WW:
    Yes, the 601 and the Corvair are a very good match. At Oshkosh, we spent a lot of time with the Heinz family, and they pointed out that the firewall bolt pattern has been the same on all 601 models for a long time. Thus, my work with Neil Hulin and others on 601XL projects applies to the previous models as well.
    The 601 has enough room in the engine compartment to install a turbo without crowding things too much. While it isn't needed to have good performance on the 601, the turbo is an interesting potential option. The XL has a 180mph Vne. A turbo motor at medium altitude (8,000-12,000 feet) would really make this airplane scoot. The high Vne is important because Vne is based on true airspeed, not indicated. If the Vne of the airplane was low, say 140mph, even a modest turbo Corvair motor could exceed this at altitude.
    I'll have more information on my turbo testing in the next Corvair Flyer newsletter.

    Subj: Vacuum pump
    Date: 8/5/03

    I caught your forum at AirVenture and had a question which didn't spring to mind until the drive home. Anyway, here goes: Do you know of anyone using an engine driven vacuum pump with a Corvair powered aircraft? Thanks for a very informative forum.

    Bryan Bowlsbey, R70BWB1@wpo.cso.niu.edu
    Reply from WW:
    No one that I know of, but many people are using belt driven pumps, and such an installation would be fairly easy on a Corvair. Everyone I can think of is using electric gyros.

    Subj: Stromberg carb
    Date: 8/4/03

    I hope you had a great time at AirVentures 2003! I need some info on the Stromberg carb. I've got a C-90 carb, but the previous owner says it leaks and no matter how many rebuild kits he uses, it still leaks. Is there a company that can rebuild the unit for me - and hopefully do it correctly? The project may hinge on the carb. Semper Fi,

    Dan Edwards, Dragonfly, newtonsrun@msn.com
    Reply from WW:
    A conservative estimate from Oshkosh would be 500 planes on the field with this exact carburetor. I did not notice any of them leaking fuel on the ground. This suggests the chances are excellent that your carb can be made to behave. Pat Panzera had a good source for needles and seats, but first check to make sure the float height is not ridiculously high. The rubber tipped needles in these carbs seal very well, but may be incompatible with auto fuel. A little careful homework here should yield you an excellent carburetor.

    Subj: Piston skirts
    Date: 8/3/03

    What is the difference in the long skirt TRW pistons and the short skirt? I know the long skirt are 1/2" longer, but is there that much difference in weight? And would it be ok to use the long skirts? Thank you in advance.

    Bob Glidden, Manual # 5471, glidden@ccrtc.com
    Reply from WW:
    The long skirts will work as a set. Our application is low rpm. Short skirts are usually aimed at higher rpm applications. The past few years of TRW production have been short skirts and these work fine. But, there was nothing wrong with the previous pistons. They weigh slightly more, but the strength of ARP rod bolts negates this difference. The only issue is that you cannot mix long and short skirts in the same engine.

    Subj: CH 701
    Date: 8/2/03

    I hope you are well. I have made my choice: The Corvair and the 701 are the only combo that make any sense in my world. So how can I make this work? Am I to be left out when hundreds of 701s are in the air with other heavy auto powerplants? Am I missing something here? Why have the Gods of aviation vexed me so? Is there any hope? Thanks,

    Steve Harmon, Ohio, iceman2@sbcglobal.net
    Reply from WW:
    Don't think of it as the gods vexing you. Rather, they are giving you an opportunity to show just how devoted to aviation you are. If you won the lottery, bought a turboprop Malibu and had a supermodel wife who also was a pilot, you'd probably fly a lot, but this would prove nothing of your devotion and love. In your situation, where you face adversity, hardship and moments of frustration, all under fiscal constraint, when you eventually triumph, the gods will reward you with many hours of wonderful flights because you proved worthy and only cursed them under your breath in moments of real frustration. The Heinz family reiterated their position that they do not like engines over 200 pounds on the 701. I seriously doubt that hundreds have flown with motors above this weight. The number is probably close to two dozen or so. Obviously it could be done, but the Heinzes do not encourage it.

    Subj: Crank case vent
    Date: 8/1/03

    Great site! Thanks for taking the effort needed to supply this great info!

    I have noticed that you offer a top cover to replace the stock cover with the fan bearing on it. Do you vent the crank case anywhere? There is a vent on the stock cover is there not? Is a vent needed and if so where/how is that done with your cover? Thanks in advance.
    Brandon, brandon@jdhgroup.com
    Reply from WW:
    Through much experimentation and testing, I've found the best place to vent the engine is through one of the valve covers. There is a lot less oil thrown around in the valve cover and a simple Cessna 150 air/oil separator does the job. This leaves the top cover free to be a simple sheet and greatly simplifies front starter mounting.

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