William Wynne

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


Ask The Authority!

July 2003 Daily Question & Answers

NOTE: To search for anything on this page, the toolbar on the top of your browser has an Edit function with a Find on This Page feature. Just type in the key word in which you're interested, and the Find feature will take you right to it. If you don't see your question answered here, or at one of the following pages,

November-December 2003 Q & A Page

October 2003 Q & A Page

September 2003 Q & A Page

August 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: Serial number, heads
Date: 7/31/03

I cannot find a listing for a Corvair with the serial number ending in RB. Also, how do I identify types of heads? I have found four in a wrecking yard, but no engines...they might be usable for aircraft use and then again they may not be....by the way, I bought manual #5441 from you...

Bob, rwbtoy@fireserve.net
Reply from WW:
I don't have to check the book on the RB code. It is a 1965-66 164cid, 140hp motor for a high performance Corsa model. I know this because my land based Corvair is an RB coded 1966 Corsa convertible. Corsas only came with manual transmissions, so you have no worries about the retarded cam gear which came on 140 motors with auto transmissions.
Everything on this motor is good for rebuilding and flying except the heads. The crank is the same 8409 forging, but it is nitrided, a small plus. Just get a set of '65-69 95 or 110hp heads and you're in business. Note that the old 140 heads should bring $200 on eBay, more if you have the linkage and carbs. The heads you need are worth half of this. A Corvair car collector would swap you heads in a heartbeat. Let me know what you find.

Subj: Corvair Power 4 Gyro
Date: 7/30/03

I want a SMOOTH reliable engine (that does NOT sound like a snowmobile) for a tandem gyro...probably Air Command here in Texas. Operational weight of ship should be around 1200 lbs. Subaru is too complex. Do you think Corvair is a realistic solution? Regards,

Charley, thejones@ev1.net
Reply from WW:
Gyros are not my field of expertise, but I listen to people who know them well, and I think the combo will work. The Corvair has a double-sided thrust bearing and is a proven pusher engine (its thrust bearing was designed to work in this direction). A smaller diameter prop on the motor, typical of gyros, will be an advantage to the Corvair; it builds HP faster than prop efficiency declines for a net increase in thrust. It is simplicity defined, and no aircraft powerplant can compete on a cost basis. This said, it also has a very nice note to the ear, which leaves two-stroke and four-cylinder guys a little envious. Let us know how we can help.

Subj: T-51
Date: 7/29/03

I was reading about the T-51 produced by Titan Aircraft (Ohio). What are your thoughts on a Corvair for this aircraft?

Jim Rogers, Mena, Ariz., docuome@msn.com
Reply from WW:
I've seen this aircraft in person and it is a beautifully made, light weight, kit. Although its performance may put it in the Sport Pilot category, it's not likely to be eligible because the category proposal includes only fixed gear airplanes.
A while back, I had someone else inquire about putting a Corvair on this airplane. The response from Titan indicated that the aircraft is so specifically engineered for the Rotax engine that it would be very difficult, to say the least, to install other engines. Also, the kit carries a very high price tag. There are a number of other high end kits much more suitable to the Corvair. But, I understand your attraction to this beautiful airplane.

Subj: Rings Question
Date: 7/28/03

After scouring the Manual for information on rings, I see a moderate endorsement for chrome. In my exchanges with Larry S., I'm told he also has moly rings as well. Clark's seems to have two different finishes for their rebored cylinders, one of which is intended for moly. Do you have any input to offer on this issue?

Clay "Hoppy" Hopperdietzel, Vision, Tomball, Texas, hoppy@houston.rr.com
Reply from WW:
I have flown all three major types: cast, chrome and moly. They all work. Most of the motors I build have chrome rings and standard wall finishes. Cast rings break in very fast, but are not as good at high operating temps. Moly can take a while to break in, especially if the first hours of operation are a lot of mild ground running. Chrome is sort of middle of the road, and they have proven themselves in some very harsh tests we have run.

Subj: Complete motor
Date: 7/27/03

I'm in the process of building a Zodiac 601XL and have heard you may be able to supply a 100-110 HP engine. I live in Alberta, Canada. Can you pass on some costs, etc.

Dave, Zodiac 601XL, Alberta, Canada, dnimigon@telusplanet.net
Reply from WW:
My primary business is teaching people how to, and assisting them with, building their own engines. You can learn more about this throughout my www.flycorvair.com Web site. Although it is not my primary focus, I do occasionally provide complete motors. That story is also on the Web site. Click on complete engines at the FlyCorvair.com Online Catalog. I'm doing a lot of work to develop the Zodiac 601 installation and make it as easy as possible for 601 builders. I've already made several motor mounts and have a very accurate jig in which to produce more. There are a few more items to work on specific to the 601 installation, such as a cowling and intake manifold. All of my other products are applicable to a 601. The bible of flying Corvair motors is my Conversion Manual, and either way you go, it's the starting point where every one of my customers begins.

Subj: Correct Corvair engine for aircraft
Date: 7/26/03

I am going to go out and scout around the Memphis area for some corvair engine cores. Are there certain model numbers/years/serial numbers that are preferable or should be avoided at all costs? Thanks in advance,

Rick Pellicciotti, rick.pellicciotti@fedex.com
Reply from WW:
You are looking for a 164cid motor, a 1964-69 110 or 95 model. My Conversion Manual, available at the Online Catalog, has about 10 pages on codes, castings, engine selection and where to find the best engines and what to pay for them. Every month we get a letter from a guy who was looking at worn out Continentals for $4,500 and then got a "deal" spending only $900 on a 1962 Corvair, and now that he's got the Corvair, he wants a Conversion Manual. 1962 motors are the wrong year and they are worth less than $50. Please send me the letter codes before you buy anything, or you can get the Manual from us. Do not pay any more than $300 for a motor.

Subj: Corvair Conversion Manual, 2002 Edition
Date: 7/25/03

I want to buy Corvair Conversion Manual, 2002 Edition. Can I send you cash through your postal address, and then you send me my copy?

And I have a question... This is my first time to even think of building my own engine, is it kind of possible to make it happen without any help other than the Conversion Manual? Sincerely,
Mulusew B., doilicho@hotmail.com
Reply from WW:
A number of first time engine builders have completed Corvair motors by studying my Manual closely and doing the work as outlined. Keep in mind I encourage builders to e-mail with questions as often as they like. If you are in the U.S., the Manual is $59, and outside the U.S. there's a $15 international S&H fee for a total of $74 payable in USD to William Wynne, P.O. Box 290802, Port Orange, FL 32129-0802. Most of our builders are first time engine builders. I've noticed that first timers read the directions with greater attention than people with experience who feel they don't have to pay as much attention.

Subj: Vision Personal Corvair Cruiser
Date: 7/24/03

Hi guys. Here attached are the photos William took of Morgan. Enjoy!

Grace Ellen, FlyCorvair.com Ask The Authority

Reply from: Steve Rahm, Vision001@VisionAircraft.com
Thanks, I'll get some of them on the site. Have a great trip!!

Steve, Vison Personal Cruiser

Subj: Prop Spinners, Flying Piet
Date: 7/23/03

Thanks for the "Corvair Flyer" in the mail ... it's a great publication. I'm very interested in the front spinner plate that you come up with for wood props using the Van's 13" spinner. I'll buy one when you get them ready!

Another Piet is soon to fly on Corvair power... Carl Loar's stock Piet with a very plain-Jane 164 CID. I'll let you know when he does his first flight and see if he gets some photos. He's just completed weight & balance so it won't be long.
Oscar Zuniga, San Antonio, Texas, taildrags@hotmail.com, www.flysquirrel.net
Reply from WW:
Good to hear from you. Please encourage Carl to contact me. A number of guys somehow figure they don't want to bother me before their first flight. I'd gladly spend an hour on the phone going over a checklist of items with anybody. Although it's all in the Manual, invariably in conversation I can find something that was left undone.
I'll put a post on the FlyCorvair.com Online Catalog when I have the front spinner plates available.

Subj: CG
Date: 7/22/03

Hope Oshkosh treats you right. Wish I could be there. Question: Where is the CG located for your engine conversion with the front starter? Weight should be considered to be right around 225 lbs. for weight and balance calculations? Thanks.

Oscar Lind, Seattle, Wash., oscar@waggonerguide.com
Reply from WW:
Depending on a number of small factors, the exact CG location is variable. But, you can get a pretty accurate calculation figuring the CG to be in line with the #4 sparkplug.
225 represents the engine with the oil in it and the systems to run it. Mounts weigh 5-6 pounds, props are in the 5-10 pound range.

Subj: Murhpy Rebel/Corvair
Date: 7/21/03

I have been considering a Murphy Rebel as a project, but have been put off a bit by the cost of the 912s and 235s that they recommend. Now, after reading through your Web site, am I seeing a viable alternative in a Corvair engine? I have always had very good luck with them (a VW conversion and a Porsche 356 conversion back in the '70s ). I never had any problems with those engines at all ! I'm not fully versed yet in all the math needed to figure this all out, but I can build one of those motors. What do you think?

Allan Nelson, Seattle, Wash., allan@wattsrv.com
Reply from WW:
I have always liked the Rebel since it came out 10 or 12 years ago. Your positive experience is typical of people who have actually worked with Corvair engines. I am sure the Rebel can be suscessfully powered by a Corvair.

Subj: Zenair 601 Motor Mount
Date: 7/20/03

I'm writing to confirm that you propose to use the 38mm long x 3/8 ID washer and welded tube firewall attachment depicted in the lower centre of diagram 6-YE-2 that I provided to you. The original engine mount fittings that mate with the mount attach points have the short bolt for the Jabiru mount. I'm getting the O-235 mount fittings from Nick @ Zenith and will be installing those in the next week or so unless you tell me otherwise.

Neil Hulin, Zenair 601, Cincinnati, Ohio, nhulin@hotmail.com

Reply from WW:
I thought I'd post a photograph of your new motor mount. Also in the above photo is my 601 Corvair Motor Mount Jig. As you noted, it shares the same fuselage mounting points as the 235 installation.

The mount weighs 6 pounds on the nose. It turns out, after careful calculation, the Corvair's prop flange will be 2" ahead of where the 235's is. This is mandated by the fact that the Corvair is a significantly lighter engine. Because the Corvair has no mags on the back, there is a generous amount of room in the engine compartment which always makes for an easier installation. The 601 and the Vision have this space in common, and are the best candidates for my upcoming turbo installation.

Although I'm very busy, I'm planning on bringing your mount and one other 601 mount to Oshkosh. If anyone out there would like to bring the second mount home and save on the shipping, send an e-mail to WilliamTCA@aol.com and let me know.

Subj: Starter Kits
Date: 7/19/03

Do you still have the starter kits available? If so, what is today's price and do you take PayPal for that like the rest of the stuff?

David Voit, Vision Corvair Cruiser, Lodi, Calif., dvoit@pacbell.net

Reply from WW:
We're getting a big batch of stuff ready for Oshkosh and Starter Kits are one of the things we are boxing up. They will appear on the FlyCorvair.com Online Catalog with a PayPal button in a few days. I will send you a note as soon as it does. We will have a discount for Corvair Flyer subscribers also. You will see that in your mailbox in a few days as we mailed out hundreds of copies of the Summer 2003 issue today.

I built a jig for the Vision Corvair Cruiser motor mount two days ago and spent most of the day welding up Cruiser Motor Mount #1. A very rigid and compact design. The photo above shows three of my motor mount jigs. The orange one is the Cruiser jig, the green one is my well used KR2-KR2S jig, and the black one is for the Zenair 601. We'll post a photo of the Cruiser mount on the plane here on the Q&A in a few days.

Be glad to make you a motor mount whenever you're ready. At lunch I sat down and figured out that this was the 17th different Corvair motor mount design I have done. Some, like my KR-2, have sold more copies than I could remember.

Subj: ENGINE HOURS
Date: 7/18/03

I WENT THRU THE LOG BOOKS AFTER I GOT BACK AND THEY ADDED UP AS FOLLOWS:

39.5 HOURS TOTAL 18.5 HOURS IN FLIGHT

THANKS FOR ALL THE HOSPITALITY. YOUR FRIEND,

BOB LESTER, KR2, FORT LAUDERDALE, FLA., rel111901@aol.com

Reply from WW:
I got this quick note from Bob Lester and thought I'd share a photo of his Corvair powered KR2 leaving the runway at Spruce Creek for the 180 mile trip to Boca Raton, Fla. He had cruised up at 160mph at 6,000 feet. He said the engine was turning a little less than 3,000 rpm and the fuel burn was around 6 gph.

Subj: Turbo Heads
Date: 7/17/03

My name is Guy Kelly and I purchased Manual #5608. I think it was Grace that included a note with it regarding a Guy Sillikers of Sunny Corner, N.B., Canada. Tell her that he is still alive at 85 and talks as much as ever. He lives 18 miles west of me.

I have a Corvair that was modified about 25 years ago and never run. Problem is that it's a '63 turbo according to the block #T0119YR (head #3817287). Heads have been modified for dual plugs. Original centre plugged (threaded), two other machined one on each side of centre plug. Excellent workmanship. It has two distributors: the original and another on pulley end of crank by way of a bracket.

Could you use these heads, and could I put a set of your 110 heads on this motor, or should I try to get another engine? Any info would be apreciated. Thanks.

Guy Kelly, Miracmichi City, Canada, mammie@nb.sympatico.ca
Reply from WW:
Guy Sillikers was a big part of Grace's childhood. She enjoyed her months spent in Canada.

The Conversion Manual contains a lot of good reasons why a 1964-69 engine is more desirable. But your engine is somewhat of an exception. A '63 turbo motor actually has the stronger crank material and stronger rods of the 1964-69 motor. The non-turbo 1960-63s did not have these features. Forged pistons will be a little difficult to find for the 145cid motor. But cylinder heads are dirt cheap for these engines, and I would highly recommend going back to a standard set of heads for it. Dual plugs in any Corvair head require a lot of cooling fin removal right where you need it the most. Let us know how it goes.

Subj: Ultravair
Date: 7/16/03

Check this out ... what think you?

  • From: faburns@rockwellcollins.com
  • We plan on trailering the MiniMax to Oshkosh the weekend of the 26th of July and parking it in the ultralight area. Someone will be there with it throughout AirVenture. I will deliver it there the 26th or 27th then return home until Thursday the 31st, then I will stay there until the end. I had a lot of help from friends here at work and they will be there during the week too, but they would prefer it if I answered any technical questions. This engine has been in the back of my mind for years and with their help all the pieces finally came together.
  • Mary Jones, Experimenter Editor, Oshkosh, Wisc.

    Reply from WW:
    Interesting motor. I'm looking forward to seeing it in person. Fletcher Burns was one of my first customers to buy my Conversion Manual years ago and build a full Corvair motor. He is a clever guy and still holds the record for lowest price of a Corvair rebuild and conversion ($1,100). He is quite a scrounger and home machinist. He is an experienced builder - I know he built at least one plane, a Sonerai II.

    I looked at the photo for a few minutes and think he has got all the major points. It appears to have a cam drive VW oil pump, and I am curious as to what type of regulator he's got. He will have some new type of thrust bearing because the standard one is in the missing part of the motor. 80 pounds for it actually seems a touch high.

    I keep a lot of data on the Corvair, and I think he may well be the first guy to make a 1/3 Vair run. Several people built a 1/2 Vair inline three in the 1970s, but they are radically out of balance and have poor power to weight. If he has good solutions to the issues, he will change the landscape of the 1/2 VW world because Corvair stuff is very cheap and tough as nails by comparison. Power is going to be slightly less, because a 1/3 Corvair is only 900 to 1033cc, but most of the motors in the class have optimistic power claims.

    Technical Note from WW: Mary Jones, my boss at EAA Publications, forwarded the above message and photo to me. I thought people would like to see the photo. A few days ago, I answered an e-mail and said the Corvair is sort of an all or nothing affair in response to a guy trying to make a 3 or 4 cylinder engine out of it. Technically, the only reasonable possible combination is the full motor or an opposed twin like we see in the above photo. We'll get more information at Oshkosh and post it on FlyCorvair.com.

    Subj: Corvair in STOL aircraft
    Date: 7/15/03

    Several people, as well as myself, are interested in the Corvair engine in the Ragwing Stork, an 80 percent scale reproduction of the Fiesler Storch. There is currently a debate as to how effective the Corvair would be in STOL applications. What is your opinion on the Corvair as an engine in a STOL bird, such as the Stork?

    Drew, Ragwing Stork
    Reply from WW:
    I have received numerous inquiries on this subject. Let me take a few moments to address the general topic. Please share this with other builders who are considering the same type of installation.

    Please note that I've had no direct contact with Roger Mann. One of his builders gave me his phone number, but I've only spoken with his answering machine. Although we travel to airshows nationwide, I've never seen or met Roger. I bring this up because I've had numerous people share comments attributed to Roger that may have lost something in the translation.

    The primary concerns of an engine installation are weight and thrust. Although I have not seen what Roger's published limits are, I can honestly state this from converting many airframes to Corvair power: A standard Corvair engine installation weighs 35-40 pounds more than a direct drive VW Type I. It is lighter than a Subaru EA-81 with reduction by 25-50 pounds. It is very close to the same weight as an O-200. Modified Corvairs, such as the 190cid model, are 8 pounds lighter than the standard conversion. Specially built Corvairs have been made perhaps 10 pounds lighter still. But, the engines I will restrict my comments to are the standard Corvair models, which 90% of our engine builders are converting. This is the 164cid (2,700cc) electric start motor with no special attempt to lighten it.

    On the subject of thrust, there is a great degree of misunderstanding amongst homebuilders. Let me preface my remarks by saying I have a unique background in props, coming from Embry-Riddle Aeronautical University, having been the highest ranking U.S. employee for the esteemed company MT-Propeller, having been a dealer for many other types of props, and having owned, tested and flown many different propellers. I believe very few people making comments on the Internet could match my background on this.

    People always quote ridiculously high static thrust numbers and overemphasize the importance of diameter. If you would like a reality check on thrust numbers, Bob Barrows, the highly respected designer of the Bearhawk line of planes, thrust tested dozens of certified airplanes that came through his facility over the years. His Web site lists the exact engine make, model, prop, etc. If you study the data, you'll see that it takes something on the order of a 360cid 200hp Lycoming swinging a 72" diameter metal prop to generate 800 pounds of static thrust. This is why you should be very skeptical when people throw around numbers in the 600-700 pound range associated with 90-100cid engines.

    On the subject of diameter, consider this: Cessna built 15,000 150s with O-200s. Many people know that this airplane has an empty weight of 1,050 pounds or more and is a large aircraft by 2-seat homebuilt standards. Yet, these workhorses do all of their work on 69" diameter propellers. Cessna could have chosen any diameter prop they wanted, but 69" is their optimum diameter. It is a myth that there is an advantage to a 72" prop over one which is slightly smaller. If a Cessna 150 would have had even 150 feet per minute more rate of climb with a 72" prop, they would have put one on. The truth is, the engine made greater average thrust over a wide range of airspeeds with the 69" prop that is certified on the plane.

    Even if you're expecting much greater than 150 performance from your homebuilt, the point is that an O-200 does a very respectable job of powering an airplane as big as a 150 because it has a highly optimized propeller which stands in contrast to the 72" wives' tale.

    It is possible to get very high static thrust numbers by pitching the prop so low that its useful range of airspeeds might be below 60 mph. A lot of numbers are quoted this way. The same engine and prop diameter, pitched for an 85 to 90mph cruise, will have much lower, perhaps 30% less static thrust, but it will be a useful prop.

    We recently thrust tested a 72" Warp Drive on a Corvair without a cowling, and with a cast iron exhaust and big muffler in place. It pulled 385 pounds of thrust at 2700rpm at a pitch which would yield a cruise speed of 85 or 90mph, with a redline of 105 or 110. With a cowl and a flight exhaust, it would be 425 pounds or so. This combo would produce good average thrust over a wide range of airspeeds. In contrast, slow turning fixed pitch props are good performers at a much smaller range of airspeeds. In a contest from brake release, take off, climb to 500' and level flight to100mph, smart money bets on a setup like a Corvair or an O-200 over a smaller motor turning a heavily reduced prop.

    There is also the issue of cost. I am puzzled by designs which are labeled as "affordable," yet the designer wants you to use a motor which costs more than the airframe. Most of our customers are spending less than $3,000 total on their motors. This seems much more in line with the philosophy of plans built airplanes.

    Over the years, I have owned a tested a lot of different flight equipment. I do not comment on things I have not worked with myself. Last week a guy told me that a C-85 produced more thrust than a Corvair. I asked him if he had ever seen a Corvair turn a prop. His answer was no. I asked if he even owned or operated a C-85. He did not. I own both, and have built, flown and tested them. Some people are pretty bold about making statements of which they have no firsthand knowledge.

    I am giving 5 forums on engines at Oshkosh this year (schedule is posted at News from The Corvair Authority) . I will also be spending a lot of time at the Contact! magazine Booth 3109. I encourage anyone to come by and talk about motors and props. Be glad to share what I know.

    Subj: 601/Corvair Progress Report
    Date: 7/15/03

    I have purchased a 1968 95 HP (TA) engine, 164 CID and it has the correct heads on it, 3878569 with quench area. The interesting thing is that the engine has a "Torsional Vibration Dampener" on it, and I was told by the seller that the engine was never worked on to the degree that something like that would have been replaced. He claimed that the vibration dampener was stock because the car had air conditioning right from the factory(?).

    I will be checking the Web site frequently as your development of the "firewall forward" stuff for the CH601 may be where I'm headed.

    Thanks again for being "in the arena."

    Gerry Scampoli, Zenith 601, Manual # 5600, GScampoli@HomeMarketFoods.com
    Reply from WW:
    The last three years of Corvair production are famous for having a lot of minute variations. Years ago, I purchased a completely original RD code 110 engined 1967 Monza coupe. It had no harmonic balancer. Your experience may be similar to this. In any case, it doesn't matter because we know what we need for flying.

    I am bringing Neil Hulin's 601/Corvair motor mount with us to Oshkosh. I have several forums there (see the News from The Corvair Authority page for the full schedule), but I'll leave the engine mount on display at the Contact! magazine booth. I built a very stout and accurate jig for it. I am working from complete sets of factory drawings supplied by Neil, and the mount should bolt right up. It has correct offset, inclination and CG information for the Corvair.

    Subj: PFA Corvairs
    Date: 7/13/03

    We had a very successful day with our PFA Chief Engineer who was impressed and 'excited' by the Corvair! It was a very popular exhibit on our Pietenpol Club stand! You may be getting an enquiry from a fellow builder David Hanchet ref shipping a core over for him... Regards.

    Paul J. Shenton, Pietenpol, England

    Reply from WW:
    Glad to hear things are progressing in England with the PFA. Some people on this side of the pond often parrot the story that introducing new engines to the PFA is impossible. Your efforts on behalf of the Corvair obviously stand in contradiction to this. As always, progress in aviation is made by people in The Arena. Congratulations on your efforts so far.

    Subj: Forged pistons
    Date: 7/12/03

    Like many others, Iím having difficulty finding forged pistons. My machinist has bored my cylinders and they cleaned up at .060. Do you have or know anyone who might have a set of .060 forged pistons for sale at a reasonable price? Thanks,

    John Krumrine, Zodiac 601XL, College Park, Penn., jqk4@psu.edu
    Reply from WW:
    Please note that forged TRW pistons are back in production and the first batch will be on the shelf at Larry's Corvair Parts (phone number in my Corvair Conversion Manual) July 25. They are priced at $269 a set, and Larry says they will be available in all sizes. He is taking advance orders at this point. When you contact Larry's, please tell them you're an aircraft builder, as we're trying to get an idea of how high the percentage of forged piston buyers are aircraft guys.

    Subj: Corvair for Jodel D-18
    Date: 7/11/03

    I read and re-read all your very informative info.

    Dad was an A&P, and automotive instructor for trade schools and community schools, so reading and looking at your information to me is secound nature. ( Plenty of dining room conversations revolving around engines and transmisions! lol) And about 200 tranys rebuilt and 3 VW engines rebuilt under my belt, so I can imagine the time and work you have put into the Corvair.

    I have owned one certified plane (PA-16) w/O-235 engine and now have finally decided on building the Jodel D-18 as it's my estimate that it may be a strong candidate for the Corvair installation. Weight and balance seem to work out nicely. Do you have any personal information on this? Or comments? Thank you for all your efforts.

    Michael Pitman, Portland, Oregon
    Reply from WW:
    Jodels are well respected designs. For the models aimed at the 100hp category, it is a natural match. Perhaps the only drawback to a Jodel is its somewhat large one-piece spar, which presents a space challenge to some people building. But, its good qualities certainly outweigh minor drawbacks. A gentleman in our EAA chapter has one and raves about it. It certainly appears to be a nice flying plane.

    The Jodel's proven nature stands in contrast to a lot of new designs that crop up which generate a lot of interest, but to people working in the industry remain unproven. All aircraft, from the Wright Flyer to the 747, were unproven designs in the beginning. But the work of flight proving a design is the realm of the professional, not the sport pilot. There are actually a handful of new designs every year which are marketed to unsuspecting people who assume that the airplane is structurally sound and has been wrung out. Sadly, this is not always true. New builders have occasionally wasted a lot of time building an airplane which has never been reviewed in a magazine, flown to Oshkosh, taken on a significant flight, etc. For those who are new to aviation and building and are a low time pilot, I encourage you to build successful flight proven designs such as the Jodel.

    Subj: Oil cooler
    Date: 7/10/03

    Hope you remember me from Preston, Minn.; the can of Cherry Grove dirt? My Piet is ready to go, at least so I thought. I was doing high speed taxi and the oil temp rose to 280 degrees! I got out your Manual and ordered a folded fin cooler. Is this the right thing to do or should I install a remote cooler? My present oil cooler is an 8 fin. Also, where should the oil temp probe be located? It looks like mine is in the rear of the engine just above the oil pan. Hope to see you at Broadhead. Thanks.

    Dave Mensink, Pietenpol, Preston, Minn., dmensink@earthlink.net
    Reply from WW:
    We remember your hospitality well, and we still have our can of Cherry Grove dirt on the kitchen counter.

    A folded fin or twelve plate will be superior to the 8-plate by a mile. 280 degrees is too high. The cooler should make a difference. Also note that twice in the past year we've had two customer oil temp problems turn out to be faulty gauges reading high. Your Pietenpol style setup with the blower fan is particularly resistant to high temps. Please note there's several little sheet metal pieces that mate with the top shroud to ensure the air's directed over the cooler.

    See you at Brodhead.

    Subj: Dual Points Distributor
    Date: 7/9/03

    I purchased the Conversion Manual from you a few months ago and I have since noticed that there is a Mallory dual points distributor from Clark's. Is this similar to what you do when you rebuild one?

    Scott Laughlin, cookwithgas@hotmail.com
    Reply from WW:
    The Mallory is aimed at high rpm racing. It has only three lobes and each set of points runs half the motor. The idea was that the points wouldn't get worked as hard if the motor was spun to 7,000rpm. My setup uses a six-lobed cam to create redundant ignition. Since we turn less rpm than the car did, we have no problem with point life.

    Subj: The New Conversion
    Date: 7/8/03

    We finally got our engine running. It may need some more tweaking, but is not broken in by any means. We had a terrible time starting it (hand prop) until we had about an hour of ground running on it. The problem seemed to be the terrible strong drag on the cast Grant rings. It was so hard you couldn't tell when you were coming up on compression, but that is getting a lot better with every run. We are using the breakerless distributor set about 12 degrees initial and haven't gotten enough courage to try to see what kind of advance we are getting at full throttle. It turns 3,000rpm static and a little over on takeoff. First flight was today (about 15 minutes) and so will have to get some more time to get the readings finalized. Rich reported the airspeed read 85 at level flight and the GPS said 71mph over the ground. We think our oil temp is a little high and will be working on lowering it some. --240 degrees "F" at the filter. I don't think we have enough outlet on the bottom cowl so will open that several more square inches next. The John Deere Dynamo works great so far. We are not electrical engineers so don't know how long the "Goldwing Motorcycle" battery will take the 14.2 volts. I think it will depend on the amperage more than the voltage??

    We aren't going to make the Brodhead Pietenpol Fly-In. I (Ray) am an early Hatz builder, Serial No.#6 1981. Although I don't own it anymore, I'm pledged to attend the 35th year Hatz Reunion at Merrill, Wisc., that same weekend. I will attend the Grass Roots affair at Brodhead in September. Maybe Rich will fly the Pietenpol over there for his only cross country this summer.

    It has been a long and frustrating task rebuilding the Corvair but I hope it will prove to be worth the effort. The biggest problem we found was the baffling and the remote mount filter and cooler.

    Well as my old TWA captain buddy used to say, "Keep the oily side down and the shiny side up" and we will hope to see you some day at a Sport Plane Fly-In.

    Richard & Ray Hill, Pietenpol, raydot@pcpartner.net
    Reply from WW:
    Congratulations.

    It will get much looser, as I am sure you know. 240 is not too high if this is before the cooler. It will drop 20 or 30 degrees when the cylinder friction goes down. Generally this takes 2 to 5 hours.

    14.2 should be fine; check the water in the battery frequently, but this should not be too high.

    It may have been work, but if building and flying planes was easy, then everyone would do it. I am sure you know it was worth the effort.

    Subj: Metal Props
    Date: 7/7/03

    My name is Samuel and I'm building a Midget Mustang (MIA) from kit. The plane is designed for engines from C-85 CFJ with prop diameter of 58" up to 150hp engines as Mustang Aeronautics (maker of kit) publish. The Corvair engine is a good choice for me and I would like to know if it accepts metal propellers as well? Many thanks.

    Sam Tor, Midget Mustang, Israel, torsh@zahav.net.il
    Reply from WW:
    A good friend of mine has an 80% complete Midget Mustang. I just made a Corvair to MM mount for it two weeks ago. A picture of it is below. My friend has owned one before and thinks they are great planes.

    I do not aprove of metal props on Corvairs. Most people no longer fly fixed pitch metal props on things like Midget Mustangs because the speed of the plane requires the prop be pitched out of limits. People have been killed doing this, so the general thought is that wood props are the way to go. (Popular fast homebuilts like 360 powered RVs have special metal props made for them.)

    Subj: Ballast Resistor
    Date: 7/6/03

    Where does the ballast resistor fit into the ignition system?

    Fish Fischer, Dragonfly, Warrenton, Ore., fishhole@pacifier.com
    Reply from WW:
    A ballast resistor's purpose is to lower the 12 volt system voltage to the coil for continuous operation. Thus, it is in line, in the 12 volt line, to the positive side of the coil.

    Subj: Stromberg Carb
    Date: 7/5/03

    I have a question about the Stromberg carb. I have found one and the guy who is rebuilding it for me says that he is installing the large needle valve and that he has a venturi that looks as if it has been polished (?) and maybe about 40mm. My question is: Does this sound good for our application? I am thinking with the bigger venturi maybe I can feed the motor more fuel, i.e. more power. Yes -No? He says he is also setting it up for running with a fuel pump 2-4psi. I believe your Conversion Manual states that the stock pump runs about 5psi, so I will have to also run a regulator. If I am running a boost pump (Zodiac CH601 XL), will the stock fuel pump handle the extra pressure or should I run a fuel line from the boost pump to the carb bypassing the stock pump? Thanks for any help.

    Doug Cowlthorp, Zodiac CH601 XL, Winnipeg, Canada, thorp@escape.ca
    Reply from WW:
    If the venturi is actually 40mm, it's probably too big for a Corvair. The Corvair will run surprisingly well on carbs as small as 32mm, and in some cases we use 35s. But, if you do the math, a 40mm carb has a drastic increase in area that the Corvair does not need. Too big a carburetor sacrifices some desirable characteristics, such as accurate metering at WOT. A Corvair fuel pump is in the 5-6psi range. I have seen it run being fed by an electric fuel pump, but test your pump carefully. Many of them produce excessively high pressure and you would need a regulator. If you're interested in using the stock pump, perhaps you should look at an MA3 carb, as they handle fuel pressure naturally and come equipped with 35mm venturis.

    Subj: Corvair Powered SL-2 Project
    Date: 7/4/03

    I sent you an e-mail a couple weeks ago asking for Corvair engine information. Thank you for the reply. I will be getting the Conversion Manual and Corvair Flyer newsletter soon. I put together a Web site, http://geocities.com/davedpilot, to show what I've been working on. I will add more content as time allows. Check it out and link to it if you want. I put a link to flycorvair.com, if you don't mind. Thanks.

    Dave Goolsby, davedpilot@yahoo.com
    Reply from WW:
    Let me first say that you're an awesome CAD draftsman. The graphics are first rate and very eye pleasing. Secondly, your aircraft design has a very aesthetically pleasing shape to it. I'll be interested to see how it progresses for you. I have a number of people, both amateurs and professionals, working on designs specifically for the Corvair engine. The engine's affordable nature has certainly sparked a lot of creative interest. I showed your design to several people, and one relatively green guy said "Hey, that looks like a .... " so and so. About simultaneously, the experienced guys said, "Yes, all good aircraft designs bear a resemblance to another successful design." If anybody brings this up about your design, make sure you use the response of the professionals.

    Subj: 12-Cylinder Corvair
    Date: 7/3/03

    Could two Corvair engines be mounted in tandem or top and bottom to drive one prop and produce 200 + HP? One carb to feed both engines --12 cylinders !!!??? How is that for a WILD idea?

    Lynn Clark, Chappell, Neb., ilflyaw@megavision.com
    Reply from WW:
    I'm usually entertained by challenging ideas. I hear stories that many people in the business are always complaining about customers who have off the wall ideas. While we get the occasional question about putting a Corvair motor in a Lancair IV, for the most part, questions that are like yours are simply creative people exercising their imagination and I applaud this. I am certainly guilty of enjoying many a late night in the hangar with my mechanical friends and musing over such ideas. Anyone who doesn't enjoy this process is missing some of the fun. Keep in mind, though, actually building and flying some of these may be hazardous to your health. 200hp of Corvair engines would probably weigh 440 pounds. Even if they shared some items - starter, carb - it would still weigh 400 pounds for 200hp. Compared to many other automotive conversions which claim to produce 200hp, this would actually weigh less than things with radiators and cast iron blocks. As a reality check, a 360cid 200hp Lycoming has an all up weight in the neighborhood of 330 pounds. Keep up the imagineering.

    Subj: Corvair Engines on eBay
    Date: 7/2/03

    I came to your web-site from Vision Plane. Both sites gave me a push of adrenaline when thinking that I may no longer only dream of but really fly my plane! Congratulations for your perseverance and contribution to "everybody's flying pocket."

    Lately I've noticed that someone is selling several Corvair engines on the eBay. May I please have your advice about their feasibility to be overhauled and transformed into flying engines? Many thanks in advance.

    Sasha, sasha47@kornet.net
    Reply from WW:
    Thank you for your nice comments about my work. Vision aircraft are the products of my friend Steve Rahm. He is very devoted to the concept of keeping aviation simple and reasonably affordable, as am I.

    My Corvair Conversion Manual contains all the details on engine selection, head numbers, how to identify the parts, etc. It's available for $59 in the U.S. and $74 for international orders by credit card at the FlyCorvair.com Online Catalog or by check or money order in U.S. dollars payable to William Wynne, P.O. Box 290802, Port Orange, FL 32129-0802. But, basically you're looking for a 1964-69 95 or 110hp motor. Either one is a good start on building a 100hp aircraft conversion.

    Subj: Carb location
    Date: 7/1/03

    I've read your Manual cover to cover and find it very enlightening. It's refreshing to read about the real world instead of a lot of ill-informed arcticles from people who haven't gotten their hands dirty. Thank you. Question: How difficult would it be to move the carb forward to about mid-engine? The design I most want to build has a lot of structure under the back third or so of the O-200 powering it. I'd much rather power this aircraft with a Corvair. Do you have experience with the carb in other positions under the engine? Are you still as impressed with the Aerocarb? Many thanks.

    Oscar Lind, Seattle, Wash., oscar@waggonerguide.com
    Reply from WW:
    Thank you for the nice comments. The Corvair is not particularly sensitive to carburetor location. It makes its horsepower the old fashioned way, by cubic inches. I have tested countless carburetor locations, sizes and styles. The engine is a good performer with virtually any system that visually makes sense. The two features that are most counterintuitive are that the length of the tubing does not affect the horsepower output of the engine and that the engine will make its power on a smaller carburetor than would be required for the same power output in an engine with less cylinders. Our friend Steve Makish (see Steve Makish's Corvair Powered KR2 on FlyCorvair.com) is currently flying a Corvair powered KR with an Ellison throttle body in much the same location as you describe. The airplane has well over 100 hours of Corvair powered flight on it.

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