Dated Sources of Information: Example – Fiberglass fuel tanks
William Wynne
Builders:
I am now about to demonstrate my commitment to the risk management of today’s homebuilders, by “Touching the Third Rail” of homebuilding, I am going to say something that strongly disagrees with a man who since his passing has been elevated to infallible sainthood in homebuilding, Tony Bingelis. This will certainly generate hate mail, but that’s OK it just keeps the Christmas card list short.
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Before people get up in arms, let me make several statements: Tony Bingelis was a real homebuilder, He made about 10 planes, he wrote a lot of useful articles, particularly in the era when many homebuilts were plans built, and the plans lacked a lot of finishing details. Critically, while his writing didn’t include phrases like “I might be wrong about this” no where did he claim to be infallible. That aspect of his legend came later, not from people who appreciated his books (like me) but from people who wanted to have an infallible saint to follow, who’s comments were often vague enough to seem to support their particular personal myth they wanted to believe.
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Want an example? In his book on power plants, Bingelis’s advice on prop length is “Keep your prop as long as possible, as long as possible” Sounds like a witty clever idea, but doesn’t constitute any learning, testing or experience. It is just a catch phrase that countless people have used as ‘evidence’ that their belief that props turning over 2200 rpm are inefficient, and any prop smaller than 72″ makes no thrust. Let’s compare an actual data point, from a contemporary of Bingelis: Steve Wittman. get a look at this story: From The Past: With Steve Wittman 20 years ago today. I went flying with him, his prop was a Cessna 150 prop cut down to 62″, and when we were doing 195mph, it was turning 3,600 rpm. Anyone who understands anything about the life’s work of Wittman knows that if the plane would have been 1 mph faster with a 63″ prop, it would have had one. My point is that Bingelis published a lot of great detail design stuff, but when he didn’t have first hand experience, he resorted to vague hangar mythology statements like his one on props, that later generations would treat as some kind of religious body of wisdom, which is a bad concept, in a field where we are supposed to Learn Build and fly.
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One of the first things people are going to say is that Bingelis’s book has a disclaimer in the introduction. It does, stating that none of the information is guaranteed to work. Actually this is one of the things I dislike about his writing. Go back and read it with a fresh set of eyes. Nearly every chapter has a subtitle disclaimer in it saying ‘this may not work for you, you should ask around. Read his comments on tank sealers: he will not come out and say “Don’t use it” he kind of says it but has a CYA, statement about how you should “ask around for yourself. ” If that was how one was to get information, why was the book written?
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What is wrong with a Fiberglass tank in the fuselage? First , It is the least crash worthy of any tank material. Second, they put stuff in fuel today that was not even dreamed of when Bingelis’s book was written in 1986. The stuff can even be regional, and it might be in the tank of fuel you get on a cross country, after years without issue. Third, fuel tank sealers that worked great 15 years ago, don’t reliably work against the ethanol content in fuel today. Fourth, I have done a lot of high end composite work, and most home made fuel tanks including the one pictures are brittle pieces of crap, because the guy who laid them up had no training, and put about twice as much resin in the weave as desirable.
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So what is the real lesson here? I had a guy tell me that he is building a Pietenpol, and his Piet buddies, told him that Bingelis’s books are “timeless” and that he didn’t need anything other than the plans. I pointed out to him that I own an original set of 1930’s flying and glider manuals, I love them, they worth more than $1,500, but I am not going to build a Pietenpol tank out of soldered tern plate, just because that is what is shown in the plans, and 1930 or 1986, it doesn’t matter, dated information is dated information. Books on aerodynamics structures and physics of flight don’t change, however, books on materials and process do, and only a foolish person would restrict himself to information 30 years old.
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Today, there are lots of sources for proven information. There are modern day Steve Wittmans, and you should follow them, because their suggestions are based not on quaint sayings, but on tests you can study and understand.
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Above, a fiberglass 12 gallon aux tank that flew for several years in the passenger compartment of my friends Caviler, a wooden low wing plane with a 60mph landing speed. The book is one of Bingelis’s three, immensely popular books. In this one, it details all the attributes of making this kind of tank, even on planes where the tank is in the fuselage, with narry a word about the kind of risk this is. The book was published 30 years ago and Bingels has been dead for 15 years. Perhaps if he was alive he might revise his recommendations in light of modern opinions about such tanks.
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If you or your buddy have such a tank in your plane, I am not suggesting that it is “Un-airworthy” , but I am asking you as an intelligent human being to do some research and consider things. If your buddy says, “It’s been in there for years, I have seen plenty of them. besides, it is in Tony Bingelis’s book” Then he is just the kind of mythology spreader I am speaking of, and it is a waste of time to try to get him to think, he just wants an infallible source to cite as validation for him being too cheap or lazy to change it. Please read carefully: If you have seen my story:Steel tube fuselages, “Safe” planes and 250mph accidents, and you decide that you still are ok with this kind of tank, because you have given it open minded thought, I am ok with that, that is actual thinking, not validation.
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Above, dull hatchet, half hearted swipe, and it is right through. Aluminum would do much better, and I doubt any human could put a dull axe through a rotationally molded plastic tank. There are countless plastic tanks, look at SummitRacing.com and search “Fuel Cell” Yes, they are cheaper than the materials in a fiberglass tank.
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I have been an aircraft mechanic for 25 years. If I was doing an inspection on a 70 year old plane, but only used the AD’s written up to 1986, under the justification that it was a “classic” plane and the information about it couldn’t have gotten any better since 1986, the FAA would take away my License, period. If some one was hurt in the plane because it was not compliant with a post 1986 AD, then I would be looking at a complementary vacation at a federal gated community. Experimental aircraft don’t have AD’s but the logic of using up to date information is exactly the same.
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Why this stuff matters to me: I have been burned over 40% of my body. I have written very plainly about the experience, and written articles like this: Pietenpol Fuel lines and Cabanes but quite frankly, I think most people don’t really care. Improving the fuel lines in a Pietenpol could be done for about $100 and four hours work, yet, years later, 75% of the planes still have hard fuel lines on them. Some people don’t care, others don’t like me personally and will not improve their plane, just because the suggestion came from me. I write this knowing that the great majority of people will not take the information seriously. I am OK with that, I don’t base my happiness on the actions of others.
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-ww.
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To read about the contributions of Tony Bingelis to Homebuilding follow this EAA link:
