William Wynne

"The Corvair Authority"
Mail to:
Sport Performance Aviation LLC
Attn: William Wynne
1528 Virgils Way, Suite 8
Green Cove Springs, FL 32043

Open E-Mail

April 2005

Welcome to the Open E-Mail Page at www.FlyCorvair.com. Here's the concept: We answer a lot of e-mail every day, and there are a number of really good questions that our R&D allows us to dispense valid advice from. Twice a week, Wednesdays and Sundays, we're going to post blocks of these questions with answers right here. Open e-mail allows us to dispense information and answer questions in a broad forum. By checking it out regularly, builders can expand their knowledge, and keep abreast of developments.

In many ways, it will function like an Internet discussion group, where builders can reference previous questions with follow ons or even write in to share their perspective of what worked for them. As an advantage over most Internet discussion groups, the discussion will stay friendly, focused on building and flying Corvair engines, and most important, because the discussion will be moderated and edited by us, all the technical information will be factual, useful and proven. There's still plenty of room to talk about different ideas and future plans, but the center of the discussion will be reality based information to help people who want to build and fly the Corvair achieve that goal.

Here's how it works: Simply click here, E-mail WilliamTCA@FlyCorvair.com, and include the word Open in the subject line of your e-mail. Please include your name, state, provence or country, and type of aircraft you're building. If you own one of our Conversion Manuals, please include your Manual number. Our very busy travel schedule sometimes prevents us from answering e-mail as fast as it comes in. But we're making the commitment here to post blocks of answered Open E-mail questions twice a week. It is my intention in 2005 to focus 100% of my Internet communications through this Open E-mail format. Of course, regular business communications can be sent to us by normal e-mail with a different subject line. For the fastest response, please phone our hangar line, (386) 478-0396, which is forwarded to my cell phone when we're out of town (it's not necessary to call both). All of this is done to improve communications, maintain an informative, friendly conversation on Corvair conversions, and serve the ultimate goal of helping you safely build and fly your Corvair engine.

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.

Subj: Prop hub bolts
Date: 4/1/05

What diameter can I machine the rear of my prop hub so the 3/16" bolts that hold the gear and puck together will clear? I have machined it as per your drawing and have purchased your Pulley for Front Alternator Setup. I have a Ford Probe ring gear and made the puck the same as the drawing in the newsletter. Look forward to hearing from you.

Darren B., VP-2, Melbourne, Australia

Reply from WW:
If you're operating from a drawing in an early Manual, the only modification you need to make in order to utilize our most up to date front starter is to turn the barrel of the hub down to 3.250" just ahead of the 3" step at the rear. All of our production Hubs have been made this way since 1998.

Subj: Sun 'N Fun

Date: 3/31/05

I will be attending Sun 'N Fun and was wondering if you will have a selection of parts for sale or exchange at the show. Thanks, looking forward to seeing you.

Thanks, Greg Stuckert
Subj: 601XL Firewall Forward Package
Date: 3/28/05

I'm glad to see you guys are getting ready for the 2005 airshow season. I was wondering if you are planning to have the XL firewall forward stuff done, for Sun 'N Fun. I think that was your original estimate.

I'm working now on the canopy and have most of the panel complete. I'm waiting for the Stewart Warner tach to come in from my local supplier, and then I'm a few switches away from having the panel installed.

I hope all is well with you, Grace and the rest of the gang.

Phil Maxson, Washington, NJ, 601XL/Corvair

Reply from WW:
We will be at Sun 'N Fun in Lakeland, Fla., the nation's second largest airshow, April 12-18, 2005. We will be easily found in the Zenith Aircraft Booth. When we visited the factory 6 weeks ago, we came to an agreement with Sebastien and Nick again about displaying our aircraft in their booth at Sun 'N Fun and Oshkosh this year. We all agreed it worked out favorably for all of us last year.

This year, we will have a firewall forward on display, in addition to our aircraft. This will feature most of our conversion components. We will have most of these available for sale at the show.

We'll see you there.


The Hangar Gang has been working night and day to put the finishing touches on our line of 601 installation goodies (see photo below).

Stay tuned to www.FlyCorvair.com for 10 new photos from around the hangar

Above are 30 CNC bent thin wall stainless intake manifolds designed to match up exactly with our welded-on intake pipe mod. We have stainless exhaust systems nearing completion also. Additionally, the firewall forward display will show the fuel, breather, ignition and filtration systems in perfect detail. We'll have this to show people at both Sun 'N Fun and Oshkosh, and will put many, many photos of this on FlyCorvair.com as soon as we can.

We'd like to thank all the builders for their patience in giving us the time to research, flight test and develop these products. The payoff will be the builders doing installations this year enjoying the option of saving a lot of time and having a professional looking installation.

Subj: Lifters, Tach
Date: 3/30/05

I have my engine running and have had for some time, but when I purchased it in a 95% complete rebuilt state from the person who rebuilt it, the oil was already in the hydraulic valve lifters. Consequently, I cannot now set the lifters as per your directions in your Conversion Manual. (I have a noisy valve lifter now.) Can you please let me know the correct way to set them now that the oil is in them. Also can you please give me the address or Web site where I can order the Stewart Warner Tacho that you talk about, as I cannot obtain that style of Tacho here in Australia. The engine is a Corsa model, swinging a 66 x 52 inch Australian made Bolly, ground adjustable composite prop, and gives me 2600 rpm static (a borrowed Tacho). I have read your Manual about a dozen times now, and find it extremely informative. Good work.

Regards, Roger Foster, Manual #5520, Newcastle, N.S.W., Australia
Reply from WW:
First, congratulations for having a running engine in your possession. This is an excellent beginning point toward achieving your dreams in aviation.

You mention having a Corsa model. Corsa is the 1965-66 high performance option for the Corvair. If your engine block was coded RB, it was a 140hp large valve, four carburetor engine. If it's RL, it was a 180hp turbo. If it's an RR, it is the ultra rare 140hp engine with factory installed A/C. I fully understand the concept of using what's available in a remote location, but keep in mind that none of these engines are the recommended powerplant for flying, for reasons outlined in the Conversion Manual.

I understand that there is a large population of diesel powered equipment in Australia. The intended purpose of the Stewart Warner tach we use is for diesel engines. Any tooth counting tachometer setup that can be adjusted to count the amount of teeth on your ring gear will work. This may save you the trouble of having one shipped from Stewart Warner in the U.S. However, as a last resort, keep in mind that we will work to provide you with anything it takes to make your installation complete and safe.

Once the engine has been run, it's far more difficult to reset the lifters. You'll have to be very careful because you'll be working within 6" of the turning propeller. Under no circumstances give in to the temptation to run the engine wihout the prop. It's not just the engine's cooling system, it is a crucial piece which provides a flywheel and governing effect to the engine.

Subj: Safety Shaft
Date: 3/26/05

Could I use Fortal Aluminum for my safety shaft? Fortal Aluminum is a wrought Aluminum alloy plate in the 7000 series. It is VERY similar to 7075-T651 in mechanical properties. Typical minimum yield strength is between 65,000 psi (in greater than 2.5" section thickness) and 76,000 psi (in less than 2.5" section thickness) and is as strong as most typical structural steels at only a third of the weight of steel. I can get this easily. If you don't think it would be okay, I will stick with the steel version.

Regards, Darren, VP-2, Australia

Reply from WW:
I never worked with that alloy, so I don't know what it machines like. Part of the criteria for using it as a safety shaft is that it must have the ability to be threaded and machined cleanly. I do not know who Fortal's advertising manager is, but he deserves a raise. For being an uncommon alloy, you read about it quite a bit on the Web. We just completed another batch of 24 aluminum 7075 Safety Shafts. We had been sending these out for the same price as the ones we made from 4130 steel. They are CNC threaded, but even with automated processing, they cost us substantially more to produce than the steel ones. Typically, 7075 is only available as a rod, and boring the 6" long hole up the middle is considered time consuming on CNC equipment. We may go back to the tried and true .188 wall 4130 and offer the 7075 Shaft as a slightly more expensive option.
Subj: Insurance
Date: 3/26/05

Thanks again for all the great work you are doing to help keep flying affordable and safe. In reviewing the engine for sale, you note that it qualifies for Falcon insurance. Is that also true for any engine built according to the Manual's specs? I'm getting ready to purchase the Jabiru and my wife is keen on their engine also to keep the whole project as certified by manufacture. I however am crazy enough to be more comfortable flying behind something I built and know exactly what's inside. Any thoughts/help?

Thanks, Tom #5518

Reply from WW:
As far as I know, the Jabiru engines are experimental engines just like the Corvair. Four-stroke Rotaxes have certified versions, but I don't think that the Jabirus do. Our own aircraft has Falcon Insurance, and the vice president, Bob Mackey, is our rep and a good friend of ours. He has insured a number of Corvair powered aircraft. Some of these were plans built from the Conversion Manual, others are products of our shop. Either is insurable, including hull and liability. However, there is a slightly more favorable rate available on engines built and test run by us in our shop. In order to pave the way for general insurability, we had to first present the data to Falcon as a firewall forward package, a format they were used to dealing with. After this, we took great care to explain the plans built nature of the Corvair and our work promoting it to Bob. He was very receptive and as a result, we have favorable rates available to Corvair engine builders through the EAA's selected provider. This was a major project of ours in 2004, and I was very pleased when the whole plan came together.
Subj: How about a little less HP
Date: 3/26/05

I am considering a Zenith Zodiac CH 601 XL, to be built light and kept within LSA limits. I note that yours readily exceeds 138 MPH, and therefore is not an LSA qualified airplane. I donít want to go to the Rotax 912 at 80 HP, or a VW at about the same power Ė they have 4 cylinders. I really want the smoothness of a flat 6, and the lower cost of a Corvair is very attractive.

A solution would be to operate the Corvair at less than 100 HP, say about 90. A larger diameter prop could be used to keep the peak RPM down, but propeller ground clearance requirements would still have to be met. Limiting peak spark advance would reduce power, but not (materially) reduce fuel flow, so is not an attractive solution. What do you think of reducing the intake manifold diameter (give the engine a little asthma) to reduce peak power? Any other ideas?

Jack Massie

Reply from WW:
I can tell you've put a lot of thought into this, but you need not be concerned. Our airplane, when operated with the Warp Drive prop set at a high pitch setting, will exceed the speed limit. However, the ground adjustable nature of the Warp Drive will allow you to use a lower pitch setting, which will keep you within the letter and the intent of the LSA rule. Set this way, you'll have the additional benefit of an extremely strong rate of climb. As a contributing editor for EAA publications, I have spent a lot of time with people from headquarters and listened to much of the discussion about the rule. It is my belief that anyone operating an aircraft expressly designed for the rule, such as a 601XL, would not have a major issue at hand if their airplane was close to the limit. I believe that a number of aircraft, like the 601, which the manufacturer has stated and demonstrated conforms to the LSA rule, will not be the target of undue attention from the regulators. I think the main focus will be to keep people from attempting to operate 180mph aircraft like RVs in the LSA category.
Subj: FWF Kit
Date: 3/23/05

Throughout my studies of all of your documentation Iíve wondered how I will deal with the various welding jobs that will be required when I finally start building my engine. I am skilled in many areas that will allow me to build an engine and airframe (hopefully a 601). However, I lack the experience and tools to do any welding. Iím sure that I could learn and want to someday but I donít want to learn on something I will fly. Iím sure that there are other builders in a similar situation.

I read that you are working on a firewall forward ďKitĒ and plans for the 601. I look forward to seeing the finished product. With this in mind, when you are finished, do you intend to make the suggested parts available? Specifically, Iím interested in the modified head/intake tube, Lower intake ďYĒ, exhaust system and modified valve covers. If you donít plan to make them production items/services, would you be willing to provide any of them on a one time basis? Iíve been to your shop and seen you & the crewís welding first hand. World class craftsmanship! I could hire the work locally but Iíd rather spend my welding money with you to help support the effort you are giving us. Besides, Iíll be sure that itís done right.

As a side note: The materials to start framing my new shop were delivered yesterday. Iíll start building Saturday, the first step toward building an engine & plane.

Best to you and the crew, Dave Thompson, Manual # 5876, Saving to build a 601 Westminster, California

Reply from WW:
When you were here last year, we were at the beginning of the 601 flight testing. In the past year, we put about 160 hours on the plane. Once the systems were evaluated and perfected, we made jigs and tooling and now produce virtually all the parts of which you speak. Most 601 builders are not welders. For our engine program to be a success, we recognize that we have to make all the welded parts readily available, at reasonable prices. A good example are the 601 Motor Mounts. We have built many, many of these this year for builders from coast to coast. We are going to debut the lower intake manifolds and exhaust systems at Sun 'N Fun. The head milling and welding on of the alumnium pipes has been very popular this year. We've done about 50 sets. This mod is required to utilize our new intake manifold. They complement each other and hug the engine very close. Again, this is a good illustration of how all of our work is designed as integrated systems. If you'd like your heads milled and intakes welded on, you can ship them to our hangar, 735 Airpark Road, Hangar A-3, Edgewater, FL 32132. If you'd like to discuss any other work on your heads, like time serts in the sparkplug holes or stainless valves, give me a call on the hangar line, and we'll get your parts in process.
Subj: Loctite 620
Date: 3/23/05

I noticed some discussion on 620 Loctite on an earlier open email and I have some info that should be helpful to some of the readers. I work at a mine in south central Montana where the mechanics were given an 8 hour course on the many different uses of Loctite. Here is the article as it is written in the source book volume 4. Loctite 620 Slip Fit High Temp. A high temperature adhesive that has the capability to operate at 450 f (232c) for long periods. Loctite 620 fixtures in 30 minutes at room temperature, but requires a secondary heat to generate the high temperature resistance. Used to bond cylindrical parts with gaps up to 0.015" (0.35mm). 620 provides strength of 3,800 psi on steel after 24 hours.

Dan Shultz

Reply from WW:
Thank you for the tip. 620 has definitely been a great asset since we introduced it into our shop a few years ago. The only thing I want to remind people about is that the directions say you specifically have to shake it before using it.
Subj: Lead Time
Date: 3/22/05

My 601XL is coming along nicely, but Zenith's lead time for the wings is 12 weeks. During the waiting period, I will work on my engine. One question I have sounds stupid, but where do you put the oil in if I use your new Oil System? The only problem I am having (a good one) is each week or so, you come up with a newer and better revision. I know I will have to start ordering soon, so I guess that can't be helped.

I know you are busy, but what is a reasonable lead time I should plan on after I ship you my cores? I have a few months leeway and want to make sure I give you plenty of time for my order.

Thanks for your knowledge, John Butterfield

Reply from WW:
Although it seems like we're always coming up with new stuff, we've had the 601 installation completely finalized for the past five months. It takes time to get out the information during winter when we can't get it to an airshow and show it to people. If you look at our 601 Page, you'll see that the oil filler neck is integrated into the valve cover. If you send us your valve covers and filler neck, we will modify the filler neck and weld it into the right hand side valve cover and put the breather vent and return on the left hand side cover. We send it complete with fresh hardware. The price for this is $95 and includes the return S&H anywhere in the United States. Although we've been extremely busy prepping for the airshow season, the leadtime on back orders is actually dropping. Keep in mind that the Hangar Gang works on parts on a cycle. For example, we only do Distributors during one four or five day session each month. This is the most efficient way to work, and fortunately, most homebuilders can tolerate a few weeks on a part, if necessary. Of course, if you're in a pinch for something, we can always turn out something crucial overnight. The beginning of the airshow season requires the most preparation. The firewall forward display we're finishing up this week will go to Sun 'N Fun. It has an enormous amount of man hours in it, and will be of a lot of educational value to builders. But, once it's done, it will only need to be transported to the next airshow, not remade from scratch. Thus, in the coming months, we'll be able to devote more effort to getting faster turnaround on all of our parts. Keep in mind that items like Prop Hubs, Front Starter Kits and Hybrid Studs, are almost always on the shelf and ready to ship any day.
Subj: Head work
Date: 3/22/05

Regarding reworking the heads (Casting number 3856759) I've got the heads disassembled and cleaned. The valve guides need replacing, the seats are secure and serviceable. I am going to have the local shop do the valve work. I will reassemble the valves. I plan on installing this engine in a 601XL. I will use the stock oil cooler and oil filter. What is the cost of having your shop cut off the intake flange and welding on the intake tubes? At what stage would you want to do this? In the bare condition, after new guides are installed or fully assembled?

Herb Brayton, Zenair 601XL, Manual 6459

Reply from WW:
The cost of the machine work and the welding on of the pipes to the heads is $200. I prefer to do this with the heads somewhat clean, but before any other machine work is done. If the machine work is done already, we can still do the job, but it requires that we completely disassemble your heads before machining and welding. Send them to our hangar address, 735 Airpark Road, Hangar A-3, Edgewater, FL 32132, any time you're ready.

March 2005 Open E-mail Page

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