William Wynne

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


What's New

February 19, 2006 Hangar Update

Here's the latest update. It starts with two photos Grace Ellen took in the Galapagos Islands three weeks ago. There are a large number of photos here. Hope there's something for everyone. Enjoy.

Here is a belated Valentine for aquatic mammals. Grace's favorite creatures in the Galapagos were the sea lions. The highlight of her trip was swimming with one. Many of you who have called since her return have asked a lot of questions about the trip, which Grace really enjoyed.

We sent out the entire first run of Engine Disassembly DVDs the day Merrill brought them to the shop. Grace has just filled all the back orders, and we now have plenty more on hand. It's also available on VHS tape.

This is a blue footed boobie. They're a little bigger and plumper than a seagull. Other than penguins, they were the most interesting birds in the islands, Grace said.

Fifth Bearing Progress: Above is a nitrided crank, without its distributor gear and flange, in position with our Mark I Fifth Bearing Extension Shaft. If it looks unfamiliar, it's because it's designed to use the Continental prop hub also displayed in the photo. It's a CNC part made of 4340 steel. The advantage of this design is that it can use one-piece bearings, hubs and seals. It is obviously intended for fixed pitch or ground adjustable props only, as the Continental tapered flange extends to the center of the prop hub. Our Mark II design, based on the Pontiac 455 bearing, will have a typical integrated prop flange. This will require a splitting housing. The only advantage to the Mark II Style is that it will allow the use of in-flight adjustable propellers such as an MTV-1 or Hoffman HOV-62.

Keep in mind that these and the spline drive are high end developments for the Corvair. Almost all current applications can be effectively covered by properly ground ion nitrided crankshafts. Please give us a chance to make some progress on this stuff. We'll have it on the Web site and on display at Sun 'N Fun, April 4-10 in Lakeland, Fla. Answering a lot of questions individually takes away a lot of time from R&D.

We will have another update in a week or two.

Manual Ownership


Several questions came up this week about second hand Conversion Manuals. My Conversion Manual is a very expensive stack of paper for $59. What makes it worth every penny is that it comes with all of our experience. Manual owners are entitled to this. You're free to purchase a used Manual, but be fair and keep a few things in mind. Over the years, I've sold thousands of Manuals. About 50 have changed hands three or four times. They're often sold online by the kind of people who spend all day at the computer. Experience shows that these guys will bombard me with longwinded, multipage questions on fuel injection and quadruple redundant electronic ignition for six months. These endless questions are written on their employer's time clock. If I answer them succintly, seemingly terse, or ignore them, these same people have all the time in the world to call me a bastard all over the Internet. When they're done daydreaming about what they'll never build, they sell the same Manual online to another guy who's exactly like them, and the fun starts all over again. Fifty of these people and legitimate business grinds to a halt.

Also, be aware that many Manuals sold online are counterfeit. I've seen the same Manual sold twice. I've had builders ask me to autograph conterfeit copies bought online. Right now, there's a copy of my Conversion Manual for sale on eBay. Notably, it's listed as written by "Wayne Wynne." I'm actually OK with the concept that someone who cannot read my name off the front cover is no longer planning on building a flying motor. My problem is that this same Manual was for sale previously. With shipping, it's bid up almost to the price we sell it for. If somebody buys this for a $5 savings and contacts me next week, we'll be starting off with me understanding that they'll go an awful long way to save a buck; not the kind of people I like around airplanes.

To date, 98% of Manual owners have been very reasonable about this. Many father-son teams building two engines were not required to have their own Manuals. We send free Manuals to any deployed U.S. Soldier, Sailor, Airman or Marine who contacts us. The list goes on, but keep in mind it's our call based on being reasonable and serving the maximum number of builders who really want to complete an engine.

Also note that we only sell parts to people who have a Conversion Manual and a Product Rights Agreement on file with us. Enough said.

Fly In June 2-3 in Alliance, Ohio


There is a Corvair Wings and Wheels airplane and auto event coming up June 2-3 at Barber Field in Alliance, Ohio. Corvair builder Kip Gardner, who was our host at the same site for Corvair College #7 and a Midwest Night School, is spearheading the event. Forrest Barber owns the airport, and it is a beautiful, large grass strip, one of the nicest airports we've visited. I'm encouraging everyone interested in Corvairs to attend. If you have a Corvair powered airplane and you're not looking forward to Oshkosh being your first airshow, Barber Field offers clear, uncrowded air space. It is a central location and I'm sure we'll see a good turnout. It was erroneously reported that this will be a College style workshop. Although Grace and I are planning on flying up weather permitting, I just want to attend and enjoy the day amongst friends. There will be plenty of time for exchanging ideas and checking out parts, but I'm really looking forward to an aviation event where I'm not turning wrenches for 12 hours. We'll have more on the event as we get closer.

Dragonfly Wings For Sale

Ever wonder why I'm a Chevy guy? As a teenager, I was regaled by Ford fans with a thousand tales of how great the ultimate Ford engine, the 1970 351 Cleveland four barrel, was. Just like the guy in the Warner Bros. cartoon who finds the singing Frog in the time capsule and visualizes his fortune, I acquired a 351C in mint condition in 1981. Long story short, all the Ford fans with cash were nowhere to be found. After two weeks of decreasing prospects, I sold it to an old man in Vailsburg, N.J., who warned me that if I made a face, I wasn't going to get the $120. Of course, the following week, every Ford guy told me he would have given me $2,000 for it.

Fast forward to 2005. My singing Frog is this Dragonfly project. Assured that it's worth thousands, I get no offers at a fraction of that. For space reasons, the fuselage has taken up residence at the Volusia County Landfill.

But, I still have a set of Dragonfly wings with Mark 2 inboard gear in good condition for sale. They've flown before, and come with a legitimate set of plans and serial number. They're for sale for $1,000 firm now. I am only going to keep them until Sun 'N Fun. If they don't sell, they will join the fuselage in the County Landfill. This is the lowest price I can imagine for an airworthy set of wings for a two-place experimental aircraft. I am certain someone in the Dragonfly community will step up and defend the honor of their design. I do not have photos. And I won't think it's funny if you Dragonfly guys call the week after Sun 'N Fun to tell me you would have bought them for thousands of dollars.

KR Motor Mounts

It was brought to my attention that there was someone on the KR-Net offering to make motor mounts. I'm not sure if the offer was for Corvair/KR mounts. Without hurting anybody's feelings, let me say that the motor mount is the foundation of your engine installation, and even if it is made correctly, if it's slightly dimensionally wrong, the cowling, exhaust, intake, etc. will not fit. I have the only jig that makes this Mount to match all the other parts of the installation. I've made about 40 of them, including most of those flying today. I realize that there is sometimes a wait to get one from us, but common sense says it is worth it in the long run. I take a dim view of people who don't have a jig, or a KR, or a Corvair, proposing to make mounts to a design that was the result of a lot of hard work to develop.

If there's a bit of a tone to this, realize we've been working a continuous chain of 12-16 hour days. The schedule will be a lot like this through Sun 'N Fun. We're planning on a very positive, professional showing there that Corvair engine builders everywhere will be proud of. Take a look at the following photos to see what's in the works.

Here I use a forklift to unload a Zenith 601XL fast build kit. It belongs to Rick Lindstrom of California. Rick has worked on countless aviation media projects over the years, but is best known to Corvair builders as a staff writer for Kit Planes magazine. Although Rick was planning on a different project when he wrote the story on our work with the Corvair last year, he changed plans to a Corvair powered 601XL fast build. He's documenting the project for future magazine articles, and elected to build it in our shop. When completed, this aircraft will give West Coast 601 builders plenty of opportunity to see the Corvair at work in their home state.

Russell Lepre of Flight Crafters, Zenith's distributor for the southeastern U.S., brought over the kit on a trailer. He's on the left in this photo with Rick in the center and me at right.

When Rick left 3 1/2 days later, the fuselage was largely done and on the gear, the rudder was built, and its Corvair Motor Mount was installed. The work progressed quickly because of the high degree of prefabrication, along with Gus working side-by-side with Rick during his stay.

The same day Rick left, Jake Jaks showed up with his Pober Junior Ace fuselage on a trailer. Jake is Corvair College #1 Graduate #1. He is from Tallahassee and has been flying his Corvair powered Junior Ace for the past year. It was hand prop, and he brought the engine to Corvair College #9 so we could upgrade it to a Front Starter System. The aircraft is slated for coverage by EAA publications at Sun 'N Fun. In order to make a good showing, I invited Jake to bring the fuselage in for a mad, three-day, 18-hour-a-day installation session. Within 10 minutes of him showing up, Whobiscat ran inside the hangar with a field mouse the size of an egg in her mouth and promptly carried it into the back of Jake's fuselage. Attempts to dislodge the cat by turning the fuselage on its nose only led to the cat holding on internally with her claws. She eventually emerged on her own, without the mouse. The cat slept in this position on top of the fuselage for a day and a half to wait out the mouse. I locked the cat in the bathroom, and the mouse made a break for it.

Here are Jake and Grace with the finished product. It was a rare cold snap and the temperature dropped below freezing every night. I can usually outlast any customer in a long work session. Being a VMI graduate and a former Marine F-4 pilot, Jake proved to be a tough match in the hangar. He worked productively hour after hour and a lot got done. On Day 2, Jake and I engaged in dangerous brinksmanship at the Dunkin Donuts counter. We overloaded on sugar and coffee in a way that got his plane done, but probably aged us five years. He took the plane home for reassembly and the finishing touches.

Jake's engine got the full treatment. We'd previously sent the cylinder heads to Mark at Falcon. I replaced Jake's crank with a nitrided one with large radiuses. In 1999, Jake got rods with used stock bolts from the Corvair Underground. After 60 hours of time, the bearings showed the big ends of two of the rods were nowhere near round. I scrapped them, and replaced them with a perfect set from Jeff Ballard. The rest of the engine looked good internally, and only the bearings and gaskets were replaced. As part of the engine upgrade, we installed a Deep Sump Oil Pan, remade the exhaust, welded on low profile intake pipes to fit in his new nosebowl, and made a stainless intake for Jake's Stromberg. Many small details, like urethane bushings, were added. All the changes were testimony to how much we've advanced the engine since Jake's basic engine was built six years ago.

Jake's installation is such a good example of a basic gravity feed engine that I had Merrill shoot the raw material for a new DVD to cover this type of installation. Notice how the exhaust pipe gives generous clearance to the gascolator. The airbox is J-3; exhaust manifolds are stock with 1200F paint. I welded a boss for the mechanical temp probe in the bottom of his pan.

The top view shows the Starter and how we retained the stock filter housing. The oil fill is a shortened neck in the stock location. This cannot be done on a 601 because the cowling is fixed in the center and would have to be removed to add oil if the filler neck were not in the valve cover. Jake's installation is now super clean, and the engine is as strong as any Corvair flying.

Just when we were waving good bye, part of Jake's borrowed trailer's structure gave way. I sprinted all the way around the hangar row to catch him before he got to the road. Jake backed it up, we broke out the Mig welder, and he was rolling again in 15 minutes. Look for his green and yellow Junior Ace on the flight line at Sun 'N Fun.

After 41 days straight in the shop, I promised to take Valentine's Day off with Grace. Mushy romantic that I am, we spent the day at Kennedy Space Center. While it was all great, the new Apollo building was fantastic and something to stir the hearts of every American and aviator old enough to remember the courage, ingenuity and bold daring of the program. Here, Grace enjoys the observation tower with Pad 39 in the background.

601 builder Phil Maxson of Washington, N.J., showed up just as Jake was leaving. Phil brought his 601XL down to our shop at Corvair College 9. The gameplan is to complete the engine installation and finish work, then test fly it out of our hangar. It would have been done last month, but we have poured an enormous amount of resources into the crankshaft issues. With the solutions in place and communicated to builders (see Feb. 4, 2006 Hangar Update), we are returning to Phil's airplane with a vengeance. His plane is an excellent example of a well built 601 airframe with a by the book engine installation. I have promised the Heintzes that this airplane will be in show condition and ready to display in their booth at Sun 'N Fun. Every step of the installation process has been documented for future installation manuals and DVDs. This way, builders at home directly benefit from being able to observe and replicate this installation on their own airplanes.

Phil spent a brutal week in the hangar working day and night. Much of his job was to begin the polishing process on his airframe. It will have a similar paint trim to our 601. In this photo of his wing, you can see the reflection of Kevin's yellow 1967 Monza coupe and my 1966 Corsa convertible.

Here, Phil and his plane on the last day of his visit. During his stay, the wings got their final fitting and the wiring was completed (including installation of a B&C capacitor-crowbar over-voltage regulator). Before Phil arrived, Kevin and I broke down his engine and re-assembled it with a nitrided crankshaft. Although it was apart for four days, Kevin and I figure that there was barely five man hours in the job. While I don't expect builders to be able to match this, anyone who claims that there's too much work to swapping a crank is not being realistic. Phil's engine was the sixth crank replacement we've done in the past month. Anyone serious about completing an airplane will regard this as a small bump in their plans. Equally, anyone looking for an excuse to quit can use this just as well as any other event that occurs in homebuilding.

Here's a Prepreg Nosebowl on Phil's 601. It is held in place with a special wood disc that spaces it correctly behind the prop flange face. With it in this position, the sheetmetal can be fitted. Although we have patterns, everyone's firewall angle is slightly different and trimlines of the fuselage skins vary. Thus, the sheetmetal is best trimmed large and matched to the plane. Again, this is being documented for easier duplication.

Here's another view of Rick Lindstrom's fast build 601. After studying it, Gus and I were tempted to set the record for how fast you can build a 601. We were thinking something like 21 working days. But this is not the plan for Rick's plane. He's going to legitimately build it himself with our assistance firewall forward, and with small parts of the airframe. Rick will be making frequent return visits to complete the project.

If you've been to the hangar before and you're wondering where all this work is getting done, we went through a savage clean up operation in January. I've shelved all our personal projects until we complete all of the Corvair projects and back orders on hand. Realistically, the pace of work has increased to the point where I don't see the possibility of getting many hours in on our personal stuff. Thus, the 320 and Tri-Motor project have been moved upstairs. The boats are gone, and almost half the project Corvairs have been scrapped or relocated. Builders across the country should know that I'm very serious about making large advancements in the quality, quantity and diversity of products churned out of our shop.

Here's a quick sample from Phil's plane. This bracket holds the throttle cable to mate an Ellison carb to the stock 601 throttle cross shaft. The hardware is off the shelf to make it easy to duplicate.

Here's the Ellison on Phil's stainless intake. Note the bracket holding the throttle cable and the single side primer nozzle. Many, many certified aircraft have the primer nozzle to only one bank of cylinders. I started Cleone Markwell's Ellison Corvair without a primer in 20F weather without a problem. This system will work like a charm.

Builders at home should understand that prior to our January crank testing I honestly felt that nitriding was simnply a good option. This is Dave The Bear's Wagabond engine. Obviously we have it completely apart to install a nitrided crankshaft. You can check our 2005 Updates (links at bottom of page) to see that we had this engine mostly torn down for an upgrade in October, before Dave put the finishing touches on the plane. It would have been far easier to replace the crank at that time, but I had no evidence to indicate that it was necessary. We now know differently, and just like builders in the field, common sense dictates that we change our own crankshafts to nitrided ones. I have always told the straight, unvarnished story to our builders. The crankshaft issues are no different. We built our own engines just as we recommended our customers do. No one in the field is experiencing a task that we avoided. Conversely, it's the fact that we've always flown exactly what we teach builders that allowed us to discover the crank issues and communicate them to builders before anybody got hurt. I expect to see the discussions on crankshafts settle down shortly. Honestly, people who are going to take advantage of our knowledge, testing and experience will do so without further discussion. People who think that my testing does not apply to them, or are too lazy, will find a rationale not to comply with the recommended improvement. Just like political arguments, everybody's already made up their mind and all the talk in the world isn't going to bring anybody into the other camp.

At our local Dunkin Donuts, I often see a man who has told me that he worked for Ronald Reagan, he knows secret information about the Kennedy assassinations, and that he's quite sure that extraterrestrials are on planet earth right now. I always politely listen and I'm exceedingly courteous to him. S.E. Hinton pointed out that even the most primitive of societies have an innate respect for the insane. Likewise, there will be some builders who choose not to nitride their crank or take any of the measures I consider minimum requirements. These builders will find me as polite and friendly as ever, but this shouldn't be misinterpreted as my respect for their judgement.

February 4, 2006 Hangar Update

Above is a photo of Grace Ellen, high in the Andes at Macchu Picchu. Her T-shirt is from Corvair College #4. Grace and her mother took a well deserved two-week vacation to the Galapagos Islands, mainland Ecuador and Peru. Now that she's returned, we're beginning the steady accelerating pace of work that culminates 59 days from today at Sun 'N Fun, April 4-10 in Lakeland, Fla. A number of changes this year in the business, especially bringing Merrill into the Hangar Gang, will put us in a good position to bring good service and outstanding R&D to Corvair builders everywhere. It's going to be a great year. Make sure that you're a part of it.

While there has been a lot of talk about crankshaft issues, and there will be more in this update, it is important to realize that progress continues unabated. In the photo above, I'm shaking hands with 601 builder Siggy Feuersanger. The occasion is Gus and I delivering and installing Siggy's engine. He purchased one of the very first Zenith Fast Build Kits. Although it was delivered in the middle of the fall, the airframe is essentially done. It is an XL taildragger, just like our aircraft. While any airplane project is a challenge, a 601 kit is among the easiest of experimental kits to build. The 601 Fast Build Kit is a dramatic reduction in time from the regular kit. The quality of the factory work is outstanding. The Heintzes continue to make subtle improvements in the 601. Notably, the standard fuel capacity is bumped up to 30 gallons, and the leading edges are now 1 gauge thicker. We regarded it as a compliment when Siggy simultaneously placed an order for an engine with us at the same time he ordered his 601 kit. Last year we regarded crank nitriding as an option, not a requirement. Siggy selected this option, and thus his engine is flight ready without further modification. Siggy is an aviator of great experience, including flying during WWII, and working for Grumman as a flight test engineer. He's looking forward to writing a new chapter in the story of his flight experience with many fine hours aloft in his Corvair powered Zenith.

More Crank Info

Pictured above is the crank rack in my hangar. It has only half of the cranks in the hangar in it. Having this many on hand helps us in pursuit of crank R&D. A builder wrote us assuming that our testing was based on seeing two or three cranks. He proposed looking at two groups of five. I honestly told him that over the years we'd seen literally hundreds of Corvair crankshafts, and if my comments were based on seeing only 10, I'd keep them to myself. Beyond direct experience, the strength of our commentary is also based on my ability to corelate this with experts we've sought out.

In my book, Steve Wittman was the greatest airplane builder/pilot of all time, and Smokey Yunick was the greatest internal combustion R&D man. I got to fly with Steve Wittman and discuss engines with Smokey Yunick because I've never been shy about seeking out experts, introducing myself and listening to the voice of experience. My knowledge of the Corvair engine exists simply because of our testing, flight experience and the input of qualified people. This goes on continuously, and this is why our knowledge isn't static, but always increasing in quality and quantity.

Crank Procedure
The following is the radiusing and nitriding procedure which I sincerely hope all Corvair engine builders will take. The Corvair is an experimental engine and you are free to build it any way you wish. If it were a certified engine, an AD would force you into compliance. In the case of experimental aircraft, I can only appeal to your common sense and hope that you will avail yourself of what our testing has shown to be a significant reduction in risk for a very modest cost. Nitriding the crank reminds me of five years ago, when I told everyone that flight engines really needed forged pistons. A giant debate ensued, mostly on the Net. People who were not flying had plenty of arguments: "Cast pistons are good enough," "I heard people flew them for years without a problem," "I don't want to spend the extra money," etc. In the end, I convinced perhaps 95% of builders that forged pistons were the only way to go. My call for nitriding all flight engines has been met with positive review and simple acceptance from most builders. A handful have brought up the same type of arguments that we'd heard before against forged pistons. In the long term, our testing and logic will win over the vast majority of people. Nitrided cranks will take their plance alongside forged pistons and ARP rod bolts as minimums. It's all part of teaching you how to build the best engine at a reasonable cost. This is the focus of our work. No part of my work is aimed at finding out what most people can get away with.

Ion Nitriding
Builders fall into three categories: core crank stage; reworked crank stage; and flying crank stage. The situation varies a bit, but essentially I want everyone to have their crank ion nitrided.

Core Crank Builder
This is the point when your crank is in the same condition as removed from your core motor. Previously, builders had sent their cranks to us. We threaded them, ground them, and equipped them with
Hybrid Studs and a Safety Shaft. If they were also gas nitrided, the turnaround time on the crank crept up toward six weeks. We did not run an exchange; each builder got his own crank back. This has been an elaborate operation because the grinder and the nitrider are 30 and 100 miles away from us, respectively, in opposite directions. Our nitrider is also a gas nitrider, which is not as desirable as an ion nitrider. The nitrider we've selected as the best available for Corvair engine builders is Nitron Inc., in Lowell, Mass. Since it would not make sense for us to mail your crank back and forth to Massachusetts, we're now encouraging builders to have their cranks ground with proper radiuses at their local machine shop, where they also can be threaded for the Safety Shaft. They can then be mailed directly to Nitron, where your crank can be turned around in a week or two. We will still provide Safety Shafts and Hybrid Studs, and of course, the Conversion Manual contains a drawing showing the threading of the crank. Unlike gas nitriding, ion nitriding can reliably be done as the last procedure in preparing your crank. It is done at a significantly lower temperature than gas nitriding, and there is comparatively no chance of crank warpage in the ion process. This is a significant benefit and you should take advantage of it by having all your machine work done before sending the crank.

Reworked Crank
The reworked crank stage includes anyone between the core crank and an engine that has flown. You may have had your crank prepped and just kept in a bag, you may have installed it in your engine already, or you may have even run the engine extensively on the ground. In any of these cases, the crank can be prepped and shipped to Nitron directly. Again, the turnaround time will normally be one to two weeks. Engines that have been run on the ground only have not put any significant bending stress on the crankshaft. They are excellent candidates for nitriding. Again, this is another opportunity to inspect the radiuses before shipment. We will shortly have an update with some good photos on this. Keep in mind that the staff at Nitron are experts in their field, but they are not going to offer any commentary on magnafluxing, radiusing, or machine work. They are taking the highly respectable position of keeping their comments within their field of expertise.

Flying Crank
The third category is flying engines. If you have a Corvair that's flown even just a few hours, you should call me at the hangar 9 a.m. to 5 p.m. EST weekdays, (386) 478-0396, and discuss your position in detail. The reason why we're insisting on proper radiuses and nitriding crankshafts is to reduce the chance of them cracking due to flight loads. Using the right people and the right equipment, I can inspect a crank to see if any crack has started. But here is a much more reliable procedure than inspection: retiring the crank. The types of cracks that we're concerned about do not happen in cars because they do not experience the bending loads associated with flight. A crank removed from a car and given a careful ring test for cracks is a better position to start with than using a non-nitrided crank that has experienced flight loads. The flight crank may have a minute, undetected crack, and the nitriding will do no good. For this reason, I encourage people with flying engines to directly contact me. We have a large number of cranks in reserve for this program. It is in the long term interest of Corvair powered flight that we have a procedure available to retire previously flown non-nitrided crankshafts. Unlike other aircraft engines, the cores are fairly cheap, and I'm willing to shoulder a lot of the burden to make this happen. Please note that this is a trade-in program for people with flying engines only. I do not sell crankshafts outright to builders in the first two stages because this would rapidly deplete our reserve that makes the stage three program possible. We're here to help everybody, but reasonable builders will understand us prioritizing this.

Sending Your Crank to Nitron
Nitron Inc.'s address is: 26 Wellman St., Lowell, MA 01851. Nitron is run by an extremely friendly, aviation knowledgeable gentleman whose first name is Pramod. I first met him several years ago at Oshkosh. His phone number is (978) 458-3030. As we've mentioned with our other business sources, please be respectful of Pramod's time. We're providing detailed instructions here so that builders can utilize his services with a minimum of hassle and delay. If every builder needed to call and review the following procedure, or wanted to debate ion vs. gas nitriding, the process would have to be more expensive and it would take longer. I encourage builders to follow the procedure and trust my judgement that Nitron is the correct provider of what we're seeking.

Prepping
The crank needs to be as clean as possible. The fuel pump eccentric, washer and distributor gear should be removed with a puller. If you have a stage two engine, a propane torch can be used to warm the end of the crank to 300F to soften the Loctite on the Hybrid Studs and Safety Shaft. Do not subject the Studs to more than 30 pounds of torque in unscrewing them, and be cautious not to overstress the crankshaft when removing the Safety Shaft. As an alternative to propane, the crank can be left in a household oven to heat soak at 300F for an hour.

The crank should be degreased, dried off and wrapped in a plastic bag. It should then be wrapped in two turns of clean carpeting, leaving excess to protect the ends of the crank. Take a little time to build a sturdy wood box held together with sheetrock screws. Mark which screws to remove to open the box. Nitron normally deals with batch quantities of industrial goods. We want to make handling our retail work as easy as possible for them.

The cost is $150 plus the return shipping. When you're ready to ship your crank (I recommend the U.S. Postal Service for this), find out how much it costs, add this as the return cost to the $150 nitriding charge, make the check out to Nitron Inc. and include it in the box with a Nitriding Liability Statement. This Liability Statement is a simple, plain language form to help everyone understand that they are still in charge of their own risk management. This is a reasonable request. Many of the nitriding outfits I contacted refused to touch experimental aircraft parts. Others doubled their price. I believe that Nitron's process is the one we want, and it's simply an additional plus that he's willing to provide it to experimental aircraft builders at a reasonable cost.

Upon the return of your crankshaft, you'll still have to carefully clean it before installing it in your engine. But its ion nitriding will provide a significant reduction in the risk of crankshaft breakage in any Corvair flight engine.

A word about fillets: In our previous update, I wanted to convey to builders that properly radiused fillets were not a substitute for nitriding. After speaking with a few builders, I realized I need to equally convey that first class nitriding does not make bad radiuses acceptable. In extreme cases of tool marks or nonexistent radiuses, nitriding can actually make the situation worse. This is a rare instance, as most crank grinders understand what a proper radius looks like. We're working to have an update on radiuses, which will include highly magnified images to compare with your crankshaft. We're actively investigating available radius gauges to put simple tools in the hands of every builder. We're shooting to have this done next week. I want builders to understand that radiusing and nitriding are complementary procedures, and I consider both a requirement. Reasonable builders will obviously want to stack everything in their favor within the bounds of affordability to reduce their risk. We've all heard the saying "If the job of the captain was to protect the safety of the ship, he'd never leave port." The only perfectly safe airplane is one that never flys. But we're all in this to go flying. My goal is to help you do it without taking unnecessary risks. A properly radiused ion nitrided crankshaft provides a large increase in strength and fatigue resistance to a direct drive Corvair's crankshaft. Because there have been many examples that have been flown for a thousand hours without this, some builders will take the perspective that they can get away without it. Conversely, my mindset on the issue is this: If the crank will usually perform well without it, the ion process will move the engine one giant step closer toward being what homebuilders would consider bulletproof. Industry people with an in depth knowledge of metals and processes recognize that a properly done job will likely give the crankshaft an infinite fatigue life based on the loads we currently apply to it.

Ongoing Fifth Bearing Research

Keeping in mind that there are builders who would like to use the Corvair with propellers and flight loads that go well beyond what is currently considered acceptable on direct drive automotive engines like the Corvair, VW and Jabbiru, we continue work on fifth bearings and spline drives.

In the above photo are three crankshafts: The top one is from a Lycoming O-320, the middle is a Continental O-200, and the bottom is a Corvair. To resist the bending loads brought on by a flying propeller, the top two cranks have extended length front bearings. This can clearly be seen as the distance between the front throw and the raised thrust surface behind their prop flanges. The Corvair, being an automotive crank, does not have this. It counts on its stiffness across the first two throws. With light props, this has proven to work over the past 45 years. With proper radiusing and ion nitriding, I believe that most all of the flying applications today, such as KR-2s, Pietenpols and 601s, with 8 pound props, can fly with an acceptable level of risk. This is not unusual. VW engines and Jabbirus are both restricted to using props with an even smaller moment of inertia than a Corvair. It's interesting to note that the Corvair's main bearing diameter is 2.1" and the O-200's is only about 1.8". The O-320 is about 2.3".

My goal by putting a fifth bearing on a Corvair is to move the engine into a strength category falling somewhere between the O-320 and O-200. The O-320 crank seen above is approved for continuous use with 75 pound constant speed props. I'm reasonably sure you could pull a snap roll with the combination and not break the crank. The O-200 has been shown to successfully fly aerobatics with a 25 pound metal prop. This is made possible by the length of the straight section of the shaft supported by bearings behind the prop flange. We're getting closer to having a running example of just such a system. By changing the style of the nosecone, and the crank extension, the system can actually test several different types of bearings.

In the above photo are four plain bearing styles. The long one on the bottom is from an O-320. It has separate thrust surfaces in the case. Keep in mind that this is essentially serving as the last two bearings in the engine, and the strength of the system is based on the diameter of the shaft, but importantly, how far the two bearings are apart. From left to right across the top are a Corvair thrust bearing, Pontiac 455, and small block Chevy.

Our primary focus is utilizing the small block bearing as the fifth bearing. I exchanged some e-mail with our friend from Canada, Wayne Burtney, this week. Wayne is a very clever guy who is building a Pegzair. In Corvair circles, he is best known for having built a 3,100cc engine with a fifth bearing housing that utilized a Corvair's thrust bearing. He built this from a set of 1960s drawings that are currently sold by Falcon Air in Canada. The project drew attention because it was featured in Contact! magazine. Wayne shared with me that he has not run the engine, and it is currently in storage while he finishes the wings for his plane. In the past two weeks, I've received more than a hundred e-mails, varying from polite to rude, about crankshafts and fifth bearings. All contained some type of suggestion of how to proceed. Many of these clearly came from someone who'd never seen a Corvair engine in person. Buried in this comes an e-mail from Wayne which I can honestly say is the standout suggestion received: He said that he would not build his current drive again; given a fresh start, he'd base his efforts on a 460 Ford bearing and its 3.00" interior bore size. This would allow the use of a lot of existing components, like Hybrid Studs and a Safety Shaft. In retrospect, it is not surprising that the most practical suggestion came from a guy who already built an engine. Based on his thought, I studied the Clevite bearing catalog and went down to the auto parts store to pick up the Pontiac bearing. It is 3.25" and slightly wider than the Ford bearing. We're going to work on this in parallel with the small block, study both and see which yields more practical application.

A few words about research: 17 years ago, I had a Corvair engine sitting in front of me, and having read every issue of Kit Planes I could get my hands on, I was determined to make it into a good airplane engine. I was long on enthusiasm, but did not own a plane, have a pilot's license, nor enough money to overhaul the engine in one shot. I'd overhauled countless land based powerplants, but had no real background in experimental aviation powerplants. At the time, I did not realize that the articles I was reading came from people who were perhaps a single step ahead of me in the process. Although I would not have wanted to hear it at the time, it would take many hard years before we could mount an effective R&D program on any subject. Yes, it took spending money, and lots of it in some cases. But there was no substitute for the practical experience that came only with time and day to day experience; learning from experts in the field like Al Jonic, people who were making things fly, not writing magazine articles, was a real turning point. My five years at Embry Riddle was the force multiplier that enhanced every aspect of my pursuit of the affordable airplane powerplant. I read all of the suggestions that recently came in. Had there been an Internet, it's not difficult to imagine myself writing one of them 17 years ago. I've not forgotten the desire to create that drove me 17 years ago. It's more alive today in my hangar than it was in my imagination then. The frustrations I experienced then are a large part of why I'm thankful to be able to work in our hangar seven days a week in an effective manner today.

On a slightly less serious note, a handful of people asked whether it was statistically a good test to look at a small number of engines and base my nitriding recommendation on it. My recommendation is really based on our overall experience with hundreds of engines. The latest round of testing is really just a small part of this. I'm well aware of the statistical limitations on small samples. While my mathematics skills in differential equations were nothing to write home about, I was a stellar student in statistics at Embry Riddle. A lot of branches of aviation, from engineering analysis to accident investigation, use statistics, and the school had a very rigorous program of statistics classes. I was later hired by the school to teach statistics. Upon reviewing my record in calculus, the head of the program labeled me an idiot savante in statistics.

Concurrently, we're working on the spline drive, which will be a field installable front bearing unit. The fifth bearing and the spline drive share some parts in common, like the front plate. We received some mail about splines, mostly some general questions. One or two e-mails did contain comments from people unfamiliar with splines. One of these people stated that the power of a Corvair engine could not be transmitted through a spline.

The above photo shows a phantom view of the Corvair transmission and differential from the GM manual. Below it are two halves of a Corvair input shaft. The input shaft connects the clutch disk to the input side of the transmission. It, of course, is splined on each end. If you study the drawing in the shop manual, you'll see that the power from the engine in the car goes through at least six sets of splines on its way to driving the wheels. Splines are very common in the mechanical world. Virtually all cars have them in the driveline. The largest aircraft engine I've ever touched is a Curtiss Wright turbo compound R-3350. This 3,700hp piston engine drove its propeller through a set of SAE-60 splines. With 59 days till Sun 'N Fun, we're shooting to fly a fifth bearing engine there, and perhaps have a spline drive prototype on display. Seventeen years after beginning my work with the Corvair, we're in a pretty good position to conduct such tests. Years ago, I could come up with ideas, make drawings and discuss them, but today, through hard work and persistence, I've been able to assemble the skills of the Hangar Gang, including an extraordinarily skilled test pilot, a facility full of tools, instrumentation, three flying testbed airplanes, the years of experience, and contacts with expertise in the supporting industries. This puts us in the unique position of actually being able to design, build, test and perfect systems that we could only talk about years ago. My basic creativity drives the work, but we're glad to conduct this work on behalf of Corvair engine builders everywhere, and make the information available to all. It's going to be a creative and exciting year. We're glad to have you along.

Now At The Hangar

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December 2006 At The Hangar Part 1

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At The Hangar In July 2006

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OSH, Illinois and SAA June 13, 2005

At The Hangar June 13, 2005 Part II

At The Hangar In May 2005

At The Hangar In April 2005


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