Seduction, Number 50 and the 'M' Word
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Seduction, Number 50 and the 'M' Word |
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As you can see from Richard Clements' article, we have an unhappy camper as a result of our policy regarding modifications. Richard asks for an open discussion of this issue. I'm happy to oblige, and it's a good idea to remind everyone about our policy regarding modifications to the Falco design. We understand that everyone does things a little differently, and it doesn't bother us when we see a builder changing the paint scheme or upholstery. But when the changes become substantial, involve major things, appear to have little engineering involved and bring a new element of risk and possible embarrassment to the Falco design, we no longer sell parts to the builder of that airplane. When we invoke this policy on modifications -- as we have done in a number of instances -- we keep it between the builder and ourselves. It is not our intent to embarrass anyone, and we hope that the builder will change his mind -- as some have done. As we all know, under the rules of the amateur-built category, you can go into your garage, build anything you like and go fly it. There's total freedom to design and build anything you want and, within reason, the FAA will let you go fly the contraption, if only to make a single pass down a runway to prove that you don't know beans about designing and building a plane. On the other hand, airplanes have a number of inherent dangers associated with them, and it's difficult to design an airplane well, even if you're an experienced aeronautical engineer. Among our builders, we have the full spectrum of personality types. At one end, there's the ultra-conservative who has the highest regard for the engineering that goes into a design like the Falco. At the other is the rebellious type with a theory on everything and a contempt for all things conventional. Everything is too expensive, the major aircraft companies are populated by idiots, and all the world is crazy except for me. They fall in love with their own ideas, and the airplane becomes a soapbox for 'see how clever I am' speeches. It's easy to spot the extreme crazies out there, but a little knowledge is a dangerous thing. People who make changes often have great confidence in their designs and tend to not see the dangers. In the introduction to Race Car Engineering and Mechanics, Paul van Valkenburgh says "...the most humbling knowledge is that the more you learn about anything, the more you realize how little anyone knows for sure. If anyone tries to give the idea that he knows all the answers, you can be sure that he really doesn't even know the questions very well." Let me tell you the story of my friend Walter Marsh, who lives here. Walter is easily one of the smartest people I know. He's got a degree in mechanical engineering and is a self-taught electrical engineer and programmer. He can program everything from an IBM System 32, to a PC, to a controller chip for embedded systems. There's hardly a mechanical device that Walter is not intimately familiar with. Walter worked for years at Philip Morris, designing machines to make cigarettes, and then moved to another company that made street-sweeping machines. Walter can, and has, designed almost anything. He's eccentric, with few social graces, almost no patience for slow-witted people, and everyone who knows him regards him as a genius. When Walter gets his mind on something, there's no stopping him, and he becomes so focused on his current project that he barely notices the rest of the world. When I designed Gonzales, our spar-milling machine, Walter wired it and hooked up all of the motor controls. It's all a big mystery to me, but routine stuff for Walter. When this project was going on, Brenda Avery was sitting at her desk one day when Walter came to see me. She said it was the most amazing sight. Looking for all the world like a poorly dressed, white-male Whoopi Goldberg, Walter sort of fell through the door and stumbled headlong into my office with an arm-load of wires-right through Brenda's office and by her desk. "He didn't even see me!" she said. "He wasn't being impolite not speaking to me -- I didn't even exist." You get the picture of what this guy is like? Well, some years ago, Walter and a couple of friends built a two-place Quickie. As they were working on the plane, Walter developed a contempt for the design of the airplane. Much of the systems design was left to their imagination in the first place. He designed a dual-bus electrical system with redundant 14-volt systems that were joined in series for a 24-volt starting cycle-something like that. It was very sophisticated, and also heavy, which rendered the Q-II effectively into a single-place machine. Walter was at home with such things as levers, pulleys, control systems and electrical circuitry. But it's also remarkable how blind he was to obvious things. They got an experienced Q-II pilot to do the first flight, and the airplane was so badly out of rig that it required full right aileron to keep it level. They only learned about this after getting it airborne, and the pilot was able to turn in one direction only, completed a quick circuit and landed. Then Walter proposed twiddling with the turnbuckles on the control cables to move one aileron up and the other down, to correct the rigging problem. I explained to him that this would simply move the position of the control stick, and it wouldn't do a thing to correct the problem. So they heated the wing, twisted it into position and let it cool -- aren't thermoplastic airplanes wonderful! -- and then Walter was ready to take the plane up himself. He sat in my office one day as I explained to him that 95% of all accidents on first flights of homebuilt airplanes were related to problems with the fuel systems. I could tell that Walter was hearing the words, but not really taking it all in. A week later, a much humbler Walter Marsh came to my office, sat down and said, "Tell me about fuel systems." "What happened?" I asked. Walter then explained that he had three complete engine stoppages on his first flight in the airplane. And with a VW engine, the propeller does not windmill. Walter had been able to get the engine running again with the starter, but it was a frightening experience. We then went through the design of the fuel system. Like most people, Walter had heard that you should have a 'low point drain' and that the gascolator should be installed on the firewall. So he ran the fuel line through the firewall, located the gascolator down at the bottom of the firewall, right next to the exhaust pipe, and then back up to the engine. The obvious problem was that the heat from the exhaust pipe was boiling the fuel, creating a vapor lock. It was an easy problem to diagnose and fix. (Even so, Walter continued to have so many problems with the engine quitting, that the plane is now permanently retired.) I recite all this, not to embarrass Walter, but to demonstrate that even the brightest of people can make the most basic mistakes in a field that they don't completely comprehend. I've seen this same syndrome occur over and over, with the Falco and with many other airplanes. There's a built-from-Falco-plans airplane in Canada that has 6:00x6 tires, hydraulic retraction system, Mazda engine and fixed-pitch prop that's ready for flight. People who have seen it say that it barely resembles a Falco and appears to have clipped wings. It's reported that on the attempted first flight the plane would not get off the ground and over-ran the end of the runway. There's an all-metal Falco-like plane somewhere in Texas that was started by an eccentric lumber-mill owner in Alabama who thought the Falco should have been designed in aluminum, so he hired an engineer to crank out a set of drawings. The basic structure is done, but he's lost interest in the project and has sold it to an arrogant know-it-all homebuilder in Texas who told me with supreme confidence that the plane would easily handle a 300 hp engine -- he could apparently tell that by simply looking at the design -- but wanted our assistance in working out the retraction system mechanism. Fat chance. We should remember that there are also a lot of lawyers out there and that we live in a litigious society. Because of this, all companies who offer kits are forced to have a policy regarding modifications. Without such a policy, you would have a free-for-all and the wild diversions in design would come back to haunt all of us over time. It's been my experience that the builders who engage in these modifications have little understanding of the legal consequences and the potential for destroying our company. With the Christen Eagle, before you bought the kit, you had to agree in a written contract not to change the design in any way and that you would use the specified engine and propeller model number and no other. We have a policy as well, and we refuse to sell components to anyone who makes major modifications to the Falco. We're open to suggestions and changes, of course, but we would expect anyone changing the Falco design to put the proposed change through the normal process of engineering review and analysis. John Oliver has done this with the front fuel tank, as has Howard Benham on underwing tanks. We have no problem with either one of these, because they did the normal amount of engineering that any responsible company would do.
If you are going to have a policy, it should be applied uniformly. When we do this, we keep it between the builder and ourselves, and we don't want to embarrass anyone. Besides, it's a painful thing for everyone because I have always liked the people I've had to say 'no' to, and inevitably those people who fall below the line feel outraged and wronged. That's true of any policy, law or regulation. But for all the rest who follow the design, there's a benefit in having a common design and that we can all learn from our common experience with a design that's essentially the same with all of the airplanes. In the case of Richard Clements' airplane, the changes he has made and the observations he offers, first I want to say that I like Richard Clements, and there's no joy in imposing this policy on him or anyone else. I also hope he never has a problem with the airplane. On Aerolite, Richard's account differs from my memory of the events. When Trimcraft first starting making Falco ribs, they used Weldwood plastic resin glue. As Richard relates, the plywood gussets literally fell off when the staples were removed. Others reported the same thing. As we all now know, Weldwood plastic resin glue has very poor adhesion to birch plywood. Trimcraft switched to Aerolite, and we've had no further reports of problems. Second, Richard had a problem with Aerolite that appears to have been a bad batch. In his tests with Aerolite, Richard reported that the glue had little strength. A Falco-building engineer friend, Robert Cordray, tested the same batch and confirmed that the glue had little strength, but Cordray subsequently purchased an additional supply of Aerolite and found it was fine. My conclusion, and Cordray's, was that Richard had a bad batch of Aerolite. On the Bondmaster M666 epoxy glue, from what I have read of the product, it's probably an excellent product and may well be a wonderful glue. I tend to be very conservative when it comes to glues, and I wish I had a better understanding of the glue, because all glues have their peculiarities. On the other changes, it's been my experience that Richard is too quick to change things and, from my perspective, doesn't stop to ask why things are done the way they presently are. I also have trouble following the logic of some of his 'fixes'. For example, Richard bases his redesign of the retraction system on two things. When Dave Aronson's Falco first flew, there was a problem with the way the wheel well door was connected to the screwjack. This is one of those messy details in the evolvement of the Falco design, in that we hooked up the wheel well door mechanism in accordance with some drawings that Mr. Frati had sent us. In that case, the pushrod was connected to the screwjack end fitting bolt and not to the screwjack. This created some geometry problems that caused the gear to start to retract when you got excessive tension on the wheel well door pushrod in the gear-down position. It was a flat-out design error that has nothing to do with the method of retraction. We corrected this by moving the connection to the screwjack itself and changing the geometry of the pushrods. Second, Richard observed that Karl Hansen's Falco was popping circuit breakers. This was related to a problem of voltage drop caused by locating the landing gear motor relays on the back of frame 6 and by the substantial loads being imposed on the system by the full set of wheel well doors all around. We relocated the relays to frame 5, increased the wire and circuit breaker size, and designed a new '13-second' gearbox to accommodate the loads imposed by all those gear doors. How and why these things justify a complete change to a hydraulic system without a downlock system-particularly after Richard had already purchased our retraction system kit-is completely beyond me. It appears, at times, that Richard tends to hear only what he wants to hear. For example, there's the well-understood situation that when rot occurs in wood airplanes and boats, it usually happens under metal fittings. The generally accepted reason is that when condensation occurs, it will be drawn by capillary action between the fitting and the wood, and it works its way into the wood through bolt holes. The usual protection for this is to bed the metal fitting in a moisture-excluding substance so that moisture never works its way in there. Yet Richard talks in terms of metal being colder than wood, and that you must eliminate metal/wood contact to prevent rot. From my experience, neither is true. Richard decided that the way the wing tip lights and strobes were wired didn't make sense, because you had three wires in a coax cable for the strobe and also two additional ones for the nav lights. Wouldn't it make more sense to have all five wires in a single coax cable? So he found a five-wire coax, put it in the airplane and then sent me a complete description of where to get the wire so that all of you could do the same with your Falcos. But there's a reason those wires are hooked up that way. Normal aircraft wire has insulation thick enough for a 600 volts without arcing between wires, and the power packs of a strobe system sends something like 1800 volts to the strobes. This requires a special type of wire with thick insulation to prevent internal arcing, and the wires are enclosed in shielding to reduce electrical system noise. That's why the wires to the nav light are normally outside the shielding and are run as separate wiring. Richard told me one day that he was getting ready to have his engine mount chrome-plated. There's a reason you don't do that, because welds inevitably have a certain amount of porosity that traps the acids used in the plating process. The engine mount will look pretty and shiny, but over time any trapped acids will slowly eat up the engine mount. In this case, Richard changed his mind and didn't plate the engine mount. So what we have in Richard Clements' airplane is a machine that could be seen by different people in different lights. In the view of some, it would be the best of experimental aviation -- a homebuilder taking a proven design and engaging in a number of experiments and improvements, some of which may work, and some of which might not. In the view of others, you have an airplane with an extraordinary number of changes designed by a printer who has a number of peculiar theories on things. I'm sure that some of Richard's ideas are good ones, but I also think that some of them probably have unforseen implications -- how many of you forsaw the problem of flap flutter? However, if any aircraft or kitplane company designed a hydraulic retraction system without downlocks, The Aviation Consumer and product liability attorneys would tear the company to shreds -- and they would be right to do so. It's a free country we live in. I hope the airplane brings Richard many years of joy and pleasure and that he never has a single problem with it. If lives and litigation were not part of the equation, all this would be easy. Alfred Scott |
