Reply to William Wynne's "Mark Langford's crankshaft issue" blog


created January, 2011

In William's blog, much of what he writes about my crank break has a bit of spin on it...he doesn't come right out and say it, but implies and infers it. For example, William wrote:

"Many of these builders followed Markís list closely and admire his efforts. As I said, many of these people identify with him because he is the Corvair pilot they "know." I have seen this same effect of focusing on the experience of one pilot before. Many years ago, before Mark had a 5th bearing, I frequently asked builders if they would be interested in having one. Almost to a man, the people on Markís list said that they didnít think they needed one because Mark didnít have one. The week after he broke his second crank, the exact same group almost entirely reversed their feelings and now all said they wanted to look into 5th bearings. This is the nature of personal identification, but it is not exactly the kind of analytical decision making that I was speaking of at the beginning of this post. I question the idea of making a decision on flying your Corvair based on the experience of one pilot while missing the input, experience and data from several hundred others." And note that now I'm just "one pilot", while there's all this other experience and data from "several hundred others" out there flying behind Corvair engines. My, how I've fallen in stature in a month's time!

I guess you could take this paragraph several different ways, but to me it looks like WW is saying that he tried to offer fifth bearings to CorvAircraft builders, but Mark Langford's reluctance kept others from progressing to a fifth bearing, while others were forging on ahead with that latest innovation. Those who were "online" and informed know better. William wasn't even on the list between June 19th 2005 (when I broke the first one) and January 20th of 2008 (when I broke the second one), except for signing on once in 2007 to make a single post slamming some of his competition (and rightfully so). There were about 125 posts regarding a fifth bearing during that period, but none were from William. If he was "frequently asking builders" about fifth bearings during that time, it was in contradiction to his direction to me (and apparently Dan Weseman) to keep the development of his fifth bearing confidential, and it certainly wasn't on the CorvAircraft list where 700 builders would have heard it. It's hard to believe that WW would have missed an opportunity to sell something to that audience. I believe the confidentiality was an effort to keep the "movement" from grinding to a halt until a front bearing solution was developed and tested, or an outright stampede to alternative powerplants.

Another example is WW's statement that "ML#1 has not been the methodology that we have used to build engines in 6 years." That's true, but between the time I started building my engine in 2000 and the time I first flew it in 2005, their were only 36 posts to the CorvAircraft list with the word "nitrided", and only one was from William...his response in 2002 to someone's question regarding nitriding. His reply was "I have flown nitrided, non-nitrided and .010 .010 reground cranks. I think that it is not an issue. My accident broke both prop blades off at the root on a reground crank which had several hundred flight hours. I sent the crank out and it checked out dimensionally. It had a very slight amount of wear. It passed the first NDT test, but I am going to send it out to a real good FAA NDT/NDE place at the Orlando airport. If it passes, this should be a very good indicator of the cranks inherent strength...In short, there is nothing wrong with nitriding, but it is not required for flying. " Yet his blog comment implies that I was flagrantly ignoring conventional wisdom of the time. The fact is that I organized a "group deal" on nitriding Corvair cranks in August of 2005, months before William offered them for sale to Corvair builders. When it became clear that most CorvAircraft list members were opting for the inexpensive insurance that nitriding offered (and yes, they followed the "one pilot's" advice on this), William got on board as well. I realize that William "reserves the right to get smarter" (and I gave him that phrase), but as a graduate of Embry Riddle and an apparent expert on aircraft crankshafts, this might have caused him to wonder if a little insurance afforded by nitriding would be a good thing. Could it be a flaw in judgement, or an effort to keep the Corvair engine affordable for the masses?

William and I started talking about developing a fifth bearing immediately after my first crank break in 2005. I said I was going to design and build one, but William said he was headed in the same direction and he'd make one for me and then sell them to others. That made a lot of sense to me, especially since I was swamped at work, so I let him go for it. We emailed and talked about it on the phone, he made slow progress on it, but by the time December of 2006 rolled around, it had faded away to the far back burner of William's efforts, and I wasn't pressing him to finish it up because I'd been lulled into thinking just maybe nitriding was going to work out for us, and was headed to England for the next seven months.

On January 31st 2008, a few days after my 2nd break, we saw William's first post to the list regarding a fifth bearing, "Crankshafts, Part 2A", where he detailed all the things to make sure are done right to ensure crankshaft longevity. But his opinion on the fifth bearing was "I honestly feel that if these procedures are followed, the Corvair crank will reliably serve 95% of homebuilders' needs without a fifth bearing." That doesn't sound like he was trying to convince CorvAircraft builders they needed a fifth bearing.

Also in the recent blog, under "some thoughts on Corvair crankshafts", and still under the same heading of "Mark Langford's crank issue" there was much discussion of inferior crank grinding, prop strikes, detonation, etc, implying that my crankshaft had plenty of reasons to be suspect. The bottom line is that crankshaft came from William, and the crank and cam were assembled into the case by Mark Petnunius to ensure that WW's first flying fifth bearing was a perfect state-of-the art Corvair crank. There was never a prop strike on that engine, and what small amount of detonation that was experienced was minor, immediately controlled, and left no sign that it even happened on any part of the engine. But if he thinks a slight case of detonation experienced in a Corvair engine is cause for pulling the crank and magnafluxing it, the crank is too weak to start with. One thing I was told by the engineers at TCM was that detonation could not damage a properly designed aircraft crankshaft. Similarly, on crank break three, the cause is focused on my balancer and rear starter, disregarding the opinion of a former TCM crankshaft failure expert.

In another blog named "Billet cranks made in the USA", William writes about the new crankshaft that Dan Weseman is working on for the Corvair. Dan mentioned this concept years ago after my first crank break, and it's been the dream of many CorvAircraft builders, including me and most other guys who are actually flying behind Corvair engines. In a June 18th 2005 post to the list (just after my first break), Dan wrote "I will probably catch it for this but I don't think my crank will live forever in my setup. Even nitrided I (me Dan Weseman) believe the margins of strength are too small for something as vital as the crankshaft . I am set up to test one of the first batch of the WW fifth bearing setup, and would be one of the first in line for a new manufacture "beefed up" crankshaft AND the fifth bearing. But none of this stuff is ready SO... I choose to carefully fly and know that at this point I've done all I can!!"

Dan is now leading the new charge for a NEW Corvair crankshaft, and in his blog William says "Likewise, now that Dan is moving up a notch in the stress department, going to a large radius billet crank is just part of his plan to make sure that he has 200% of the strength he needs, not 99%. The most common question that people have about these cranks is "Do I need one?" My primary answer for this is that the vast majority of builders do not need one of these. That is my opinion based on the big picture of statistical evidence we have from being at the center of the Corvair movement." I guess my statistical evidence is no longer at the center of the movement. This is similar to what William said about the fifth bearing, even while he was building one for me at the time. Personally, I think anything you can do to make the crankshaft live in a Corvair is a good thing. I'm not the only CorvAircraft builder/flyer to come up with that piece of wisdom! And the reality of it is that a brand new 4340 crankshaft will have at least 50% more fatigue strength than the stock 5140 GM crank, and then nitriding will improve on that at least another 25%. But even more importantly, those critical journal radiuses where these cracks originate need to be much larger in radius to reduce that stress riser where the cracks originate! There's the smoking gun in every case. You simply can't do that with an old stock crankshaft. And in most cases that crank has already lived one life in a car engine. The stronger material of a 4340 crank would allow thinner cheeks, and those critical radiuses could be increased. And after nitriding, the radiuses should be fillet rolled to increase strength even more. The fifth bearing took care of the prop loads on the #6 crankpin journal up front, but those critical radiuses are now the weak link, especially after being ground down .010" and compromising those critical fillets. The end result will be a crankshaft that's more than twice as fatigue resistant as the most pristine stock 8604 Corvair crank. And when you compare that to the cost of the current "state of the art" in CorvAircraft cranks, it's not a lot more cost, especially if you factor in replacing a crumpled airplane! And although I've said many times that all CorAircraft engines should have a fifth bearing installed, I'll now add a "high strength crankshaft specifically designed and built for aircraft use" to the list.

Another thing that is simply false is "Some people lean their engines until they run rough, which in the case of a Corvair, it is detonating." That is simply wrong, and if William really believes that, he needs actually fly behind a Corvair for a while to get better educated. If I'm at 7500' loping along at 3050 RPM and I lean it out to roughness, it's because a cylinder finally leaned out enough to quit, not because of detonation. William knows this, but to those who may not know any better, it's another innuendo of doubt in my engine management practices, despite the fact that I don't lean my engine to roughness. I lean it by an air/fuel gauge which is verified by CHT readings. I can even tell you which cylinder it is because I have 6 EGT probes, something WW also doesn't think is necessary. If, "in the case of the Corvair, it is detonating" any time the engine is leaned out to roughness, there are a whole lot of general aviation engines that ought to have their crankshafts scrapped.

It's funny how over the past six years I've been championed by William as one of the most positive forces in the "Corvair Movement", and whenever it suited his sales pitch, my name was mentioned as a success story and my Corvair experience was a goal to strive for. Now that I've reported an inconveniently bad data point on my engine history, I'm just a "complex internet personality with a different perspective". I predict that future fifth-bearing failures will also be the fault of the builder/pilot and not the crankshaft's. You might recall that one of the factors William blamed my first crank break on was a "blob of Loctite under the prop hub". He and I both know that's a crock, but that's the story that was told. I guess I can't blame him...his livelihood depends on CorvAircraft engine sales. And I'm not surprised my fall from grace...I've always suspected this day would come. Apparently my services as the flying Corvair success story are no longer needed. Come to think of it, they're not even possible, so that makes sense.

Likewise, the CorvAircraft list has been lauded by William as the one list where fairness and even-handedness rule, without toleration for troublemakers. William has asked me many times to throw certain folks off the list, particularly competitors, but I refused to do it until they stepped over MY bounds and violated list rules, or otherwise hung themselves in other ways. Eventually William crossed that threshold as well, so yes, I unsubscribed him from the list as I have done with about 25 others over the years. A few days later he apologized, and said that my actions would prove that I am independent. I guess you might call it "bad karma" that my crank broke a week later, but the two incidents are completely unrelated. William above all others should understand why I didn't come home and immediately blurt out a "broken crank / crash report" on the list. Perhaps he's just irritated that he wasn't one of the three that I confided in regarding the break, while I waited on a "real" expert judgement on the cause of the break. I suspect he'd have been quite happy to be given a head start on spinning the situation and/or having a solution in the works before the news broke.

The week after crank break 3, I was thinking a lot about my decision to fly behind a Corvair engine, and did some soul (and internet) searching to remind myself why I chose the Corvair over the freshly built VW that I already had on hand. I already knew, I just wanted to see if I can locate a record of it. I found a post that I'd made to the KRnet list in March of 1999, in reponse to a message posted by Randy Stein. It was a quote from William Wynne that went "I have never seen a cracked head, cylinder, case, crank or rod in the hundreds of Corvair engines I have inspected. It is a very strong engine." To which I replied, "What a testimonial. I guess that new 2600cc Type 4 in the basement might be going into the Karmann Ghia now." Those words are still located on William's site, and I sincerely doubt they are true in 2012 .

I've spent the day writing this, while I should have been working on my new plane. I've collected several pages of quotes to prove various other points, but it'd take me three or four more days to assemble it and write it all up, and then William would counter with another of his well articulated rebuttals, and we could go around like that for weeks. He has a knack for re-writing history. I don't have time for it, so I'll quit with what I have above and will call it "point made". Before publishing this, I almost deleted everything above and replaced it with the following:
I'll put my reputation for accuracy in data collection, honest reporting of that data, and fairness in moderating the CorvAircraft list against William's any time. I've spent a lot of time and money proving the Corvair and "flying the Corvair flag", not making a dime off "the Movement" in the process. My attempts to make the Corvair a viable aircraft engine have been enjoyable, exciting, educational, and rewarding, and I've met and have retained a lot of great friends over the years, so it was well worth it. If "the Movement" produces a more resilient crankshaft, I'll put one in my 3100cc engine and continue the testing effort, but not until then. Besides, I'm fresh out of airplanes to test with...

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