Great tales from discussion groups…….part #1

Builders,

I often complain about disinformation on internet discussion groups, but I don’t often provide examples. Well, in the interest of humor, maybe we should look at a few…..

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The internet isn’t new anymore, and you would think that by now most people writing to discussion groups would know their comments will have a very long shelf life, and this equally applies if they are brilliant or if they are Bull.

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Actually, I suspect many of the people on these groups know this, and that it why the don’t use their names. Yesterdays “Flyboy26” who said something stupid becomes “Conexpert21” with a clean history tomorrow.

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OK, here is one of my favorites: Couple of years ago on a Pietenpol discussion group guy gets on and says he is going to use a Corvair, (Mind you, the Corvair is the designer, Bernard Pietenpol’s choice for the airframe.) He immediately  gets a negative reaction from Continental fans. Below is a sample:

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“Car engines are not designed to operate anywhere near full power for more than a few seconds at a time, whereas an aircraft engine must be capable of full power continuously.  That’s why Corvairs require such little tricks as painting the pushrod tubes white to try to keep the oil down to a manageable temperature.  Putting that engine in an airplane is asking it to do something it was simply not designed to do.  Now the Corvair guys are adding a 5th main bearing (at significant expense, negating the supposed cost advantage of using a car engine to begin with) to handle the loads that a propeller puts on the crankshaft.  There have been numerous cases of crankshafts breaking in Corvairs in aircraft, although I don’t know of any in a Pietenpol, other than Shad Bell’s. Car engines (other than the Model A) also tend to get their power at higher RPMs than are useful for driving propellers.  Props really loose efficiency when the tips start going supersonic (to say nothing of being VERY noisy – ever hear a T-6 takeoff?) and with the size props used on planes of our size that happens at about 2500 RPM.  Power generated at speeds faster than that is not very useful and there needs to be substantial torque in the 2000 – 2500 RPM range.  That’s why so many auto engine conversions require gearing to reduce the propeller speed, which adds cost, weight and complexity, and hurts reliablity.”

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OK, where do we start? – We don’t run the engine at it’s automotive power setting nor rpm limit-Painting the pushrod tubes is to protect the O-rings, has nothing to do with oil temps- It wasn’t designed as an airplane engine, that is why we converted it into one – Dan’s bearing is $1,050  and building a cheap engine wasn’t a goal, building a good one is. – Two Piets with no radius on the grind broke a crank , no damage to either plane. More than 100 Corvair Piets have flown, less than 10 have a 5th bearing.- I have well documented examples of dramatic performance increases with Corvairs and 68″ props over small Continentals with 72″ props.- 2500rpm on a 72″ prop at 60mph is barely above .7 mach at the tip. All direct drive certified engines since WWII are either 2700 or 2800 rpm rated, often with props well over 72″ in diameter. Steve Wittman disproved the slow prop myth with his Buttercup…in 1937. (He used a 64″ prop at 3,400 rpm on a plane that flew slower than a Piet) – you only need torque at 2000-2500 rpm if you have to run it at that rpm, and you would only do this if it is a pre-war design with old metallurgy like cotter-pined rod nuts.

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OK, why am I bringing this up? First, because if anyone Googles “Pietenpol Corvair” that top quote comes up as if it was written yesterday. I write a lot about how builders are subject to continuous disinformation in the guise of helpful advice. If that is what they hear all the time, and they have not see a Corvair fly a Pietenpol in person, ‘theory’ like this seems real.

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The same list has lots of stories about affordable Continental engines that are  available with accessories for $6000, and in some cases it is said these engines are “Zero timed”.  What these people don’t understand is that the original manufactured is the only person allowed to claim “Zero timed.” Below, from the Continental website:

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“Because it’s an exact science.

Continental produces a rebuilt engine to factory-new engine specifications, and we are the only facility authorized by the FAA to build zero-time Continental Rebuilt Engines.”

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And yes, it’s in the regs: “This only applies to the original engine manufacturer and may not be represented by field overhaulers.”

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 You can’t call up Continental in Mobile AL, and get a Zero time C-85 for $6K. (Small problem, they have not made a C-85 in 44 years and do not offer Zero time ones) It is worth noting that the 85 has a nearly identical parts count to a 0-200, and a zero time version of the latter is well over $18K…if you already own a good core.

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Let’s just say that a builder doesn’t know the difference between the FAA terms, Zero time, Overhaul to new limits, and overhaul to service limits. The last is not even vaguely comparable in quality or lifespan compared to the first, and I do not believe that there is a single C-85 for sale in the country with an actual legal logbook with an entry that that meets even the definition of overhauled to service limits, with the yellow tags and the accessories for $6k. Not even close. Grace’s Taylorcraft has a C-85 engine in it, and the parts alone to overhaul it correctly cost $8800 in 1999, and this did not include buying the engine nor any labor,  just the parts to overhaul it.

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The only C-85 you will find for $6K is one made of well used parts and a fresh paint job. That isn’t “Zero timed”.  The key words are “experimental only” and “no logs” when you see these engines for sale. That means they contain parts that are not legal for use on Certified planes. Such an engine will never make TBO, and if you are unlucky, it will break. When it does, you will then find out that many aircraft shops and mechanics will not touch your $6K engine. Ask any person who works in a FAA licensed repair station about having out of spec parts in the shop. When I ran the MT propeller repair station the FAA inspectors required all out of spec parts to be marked with a stamped X and kept in a locked room for condemned parts that only the director had keys to. If you have out of spec parts around, they might get into certified engines, and then the repair station gets it’s ticket pulled. That is why professional shops don’t work on junk.

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I like Continentals, and have a lot of time flying behind them. Their primary quality is reliability. but you only access this quality by spending top dollar to keep the engine the way that it was from the factory.  Anyone who thinks that you can have the reliability of a certified motor when you buy one that is advertised as “no logs” or “experimental only” is on drugs. You don’t get to have it both ways.   Continental’s reputation was not built on engines made of junk and spray painted. If the engine was just as reliable with out of spec parts, then they wouldn’t be out of spec would they?

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There are always people who argue that they have to have “a reliable certified engine” and that they will not fly auto engines. Then the first thing they do is go out and look for the cheapest collection of parts bolted together that are masquerading as a “certified”  engine. That behavior isn’t rational, but people who are compulsively cheap often are satisfied with the illusion of reliability instead of the real thing.

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Want to know who isn’t fooled by this? Our old friends Physics, Chemistry and Gravity. If the FAA considers the engine un-airworthy in a certified plane, it is just as un-airworthy in an experimental one. Physics, Chemistry and Gravity don’t care if the plane was built in a factory or your garage.  An engine built of out of spec parts doesn’t magically become airworthy when it is bolted on an experimental.

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So now, when you read something like this actual quote from the C-150 discussion group:

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“I have a recommendation for an excellent shop in Canada, with whom I’ve worked for 20 years. My O-200 was zero’d there few years ago, and I’m very happy with it. PM me if you like.

Pilot DAR”

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That the “pilot DAR” doesn’t know what he is speaking about, because you can’t get a zero timed Continental from anywhere but the factory, and the factory is 1,400 miles south of the Canadian border.

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There is some realistic advise on the net, for example the comment below:

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“You don’t really know until you open the engine up; a bum crankshaft can add thousands to the overhaul cost.  Figure on a bare minimum of $12,000 up to slightly over $20,000 depending on what you are doing and what comes up.  Remember the accessories are part of the cost and the old ones can be mostly good or all junk.”

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If you are building a Corvair and looked at Dan’s $2,200 new billet crankshaft and thought it is a good value, you are right. If someone thought that was expensive, they better not buy a worn out, undersized or previously prop struck Continental, because their new cranks cost a lot more than that, and don’t forget, they will have spent $6,000 on their ‘core’ engine, not the Corvair average of $200.

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Below is an advertisement for Don George, a respected, but fair priced FAA overhaul shop in central Florida. Note the fine print that says the core parts from the engine you already own must be reusable. If you had an engine with an “experimental only” crank in it, they would not accept it, and the price would be even higher:

Overhaul    Your Engines Price includes fuel system, magnetos, starter, new harness and spark plugs. Price is contingent on repairable crankcase, crankshaft and cylinders and    subject to applicable air worthiness directives and service bulletins.

O-200-A  (New Cylinders)			$15,818

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I don’t want to leave anyone with the impression that I think the internet is all bad. After years of having damage done by bull stories on the internet to my work with the Corvair, my new approach is to directly point out disinformation in hopes of getting people to recognize this type of story comes from people who are not an asset to home building.