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On Jun 20, 12:15 pm, Le Chaud Lapin wrote:
There are 100's, if not 1000's of features, that a general-purpose computer + inexpensive, commoditized accessories, can add to flying. I want to know which aircraft components can be "commoditized," and what that means. Does it mean that ordinary industrial or automotive bits are used in building the airplane? Where can I get such commoditized cheap parts for my airplane? It needs new wheels and brakes, which can't be replaced by car brakes because they're all too big and heavy, it needs a new engine but that engine has to weigh 178 pounds or less, it needs new radios that can tune in aircraft fequencies. Can I buy those at JC Penney or Canadian Tire? What is notable is that the cost of the $1000 PC does not increase. Only the software and accessories change. Of course, since billions of them are out there and many, many millions more are sold every year. Not like airplanes at all. We have some 172s and a 182 and a couple of Citabrias. These airplanes all came with electromechanical voltage regulators, where a small electromagnet pulls open the field current contacts to limit alternator output. The 172s and 182 are all 1970s models and ran for years and years and thousands of hours on those primitive make-and- break buzzer-type regulators, and when they did quit we'd buy new ones. Now, the manufacturer makes regulators that look the same and have the same part number, but the make-break contact setup has been replaced with an electronic control circuit. No moving parts. And those regulators last as little as a week and no more than a year or two and cost every bit as much as the old style. What did we gain there? We fly in Canada where it can get really, really cold. The epoxy cases on computer chips or transistor cases contract and crack at -40 and moisture from the air gets in there and shorts them and they're dead. Finished. This can happen when the unit is parked outside, as they often are. Next time the pilot goes to use his airplane the radio doesn't want to work right because the synthesized tuner, which replaced a bank of switched crystals, is wandering all over the place because its frequency counter chip is pooched. What did we gain there? That radio weighs as much as the old crystal unit did and lasted one fifth as long as the old one. What else would we use to encapsulate a chip that wouldn't shrink and crack at -40? The LCD displays on these things quit at -25 degrees. The liquid crystal freezes. Useless. Narco uses a special gas discharge display in many of their avionics, and that stupid thing burns out regularly. $350 for each side of a NavComm. The old mechanically tuned radios keep on going. What did we gain there? I'm not against electronics. I've worked on electronic devices since I was 14 years old, which was 41 years ago. It's just that the "advances" we've been sold aren't ready yet and cost MORE than the older ones did and are LESS reliable. We really haven't moved ahead much at all and I would not trust my primary flight controls to a single set of FBW controls. Airliners use three systems, just like heavy trucks have three separate braking systems (but only one drum/ shoe per wheel) and such redundancy adds a lot of cost and weight. Those 1/8" cables and their pulleys are going to be around for a long time yet, believe me, and it's not because we don't want electronics, it's because we can't trust them that much. My Power Mechanics teacher in high school told us kids that 90% of all car problems would be electrical, and in those many years since he's been proven right over and over again. The FAA is not against innovation and improvement. In the early '70s a guy named Ken Rand took a set of Taylor Monoplane blueprints (I once had one of those airplanes) and made some changes and came up with the KR-1. It was the same size but much lighter and slicker and went 50% faster, all using styrofoam and polyester fabric and epoxy resins, and the idea caught on and Burt Rutan refined it and built some astounding airplanes, paving the way for a host of new designs. Lots of folks thought is was crap, and the composite airplane still has lots of shortcomings (hard to repair, temperature extremes are hard on it, resins are toxic, and lightning passing through it tends to blow it to tiny bits) but we now have certified airplanes like the Cirrus and composite propellers and composite tails on airliners along with composite flaps and so forth, and the new 787 is almost all composite. The FAA is happy with it and the 787, due to its enormous strength, will have much better differential pressure for higher cruise altitudes with lower cabin altitudes, so that its worst fuel mileage will be better than the A380's best. Stop dreaming about alternate propulsion methods and fancy FBW systems and go invent and build them and if they make sense they'll sell and you'll become rich and famous. Aviation is as market- driven as anything else, and we're not resistant to innovation that saves us money or makes us safer. But we WON'T buy something that doesn't work as well as what we have now. Period. Dan |
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On Jun 20, 2:17*pm, wrote:
* * * * *We have some 172s and a 182 and a couple of Citabrias. These airplanes all came with electromechanical voltage regulators, where a small electromagnet pulls open the field current contacts to limit alternator output. The 172s and 182 are all 1970s models and ran for years and years and thousands of hours on those primitive make-and- break buzzer-type regulators, and when they did quit we'd buy new ones. * * * * * *Now, the manufacturer makes regulators that look the same and have the same part number, but the make-break contact setup has been replaced with an electronic control circuit. No moving parts. And those regulators last as little as a week and no more than a year or two and cost every bit as much as the old style. What did we gain there? A poorly designed switching regulator, a component so common in electrical design that it is often given as a project to undergraduates in electrical engineering [http://www.rason.org/ Projects/swregdes/swregdes.htm]. You could go over to sci.electronics.design and ask the other EE's what they think about botching a switching regulator and see what they say. ![]() * * * * * *We fly in Canada where it can get really, really cold. The epoxy cases on computer chips or transistor cases contract and crack at -40 and moisture from the air gets in there and shorts them and they're dead. Finished. This can happen when the unit is parked outside, as they often are. Next time the pilot goes to use his airplane the radio doesn't want to work right because the synthesized tuner, which replaced a bank of switched crystals, is wandering all over the place because its frequency counter chip is pooched. What did we gain there? That radio weighs as much as the old crystal unit did and lasted one fifth as long as the old one. What else would we use to encapsulate a chip that wouldn't shrink and crack at -40? The LCD displays on these things quit at -25 degrees. The liquid crystal freezes. Useless. Narco uses a special gas discharge display in many of their avionics, and that stupid thing burns out regularly. $350 for each side of a NavComm. The old mechanically tuned radios keep on going. What did we gain there? Bad designs. I have a spare deactivated cell phone that I keep in my Jeep for 911 emergencies. It sat in my Jeep for years. Every time I have connected it to power outlet, it works, without a problem. True, -25 is extreme, but not so extreme that reliable components could not be made for those temperature. The point here is that it is not the devices fault. If it breaks, it is because it was not engineered properly for that environment. * * * * * I'm not against electronics. I've worked on electronic devices since I was 14 years old, which was 41 years ago. It's just that the "advances" we've been sold aren't ready yet and cost MORE than the older ones did and are LESS reliable. I think this happens in aviation (and automotive industry in general). This is what I meant about inter-discipline engineering. The Dean at my university had launched a program that essentially asked, for example, the mechanical engineering department to allow the electrical engineers more freedom in designing those aspects of ME devices that required electronics, and vice versa, the idea being that, if the EE's are allowed to do the EE part, and the ME's are allowed to do the ME part, the the overall system will be cheaper, more reliable, etc, because each department would be exercising their natural competencies. There were multiple programs like this at my university, so many that one would have to conclude that this type of development was not occurring. We really haven't moved ahead much at all and I would not trust my primary flight controls to a single set of FBW controls. Airliners use three systems, just like heavy trucks have three separate braking systems (but only one drum/ shoe per wheel) and such redundancy adds a lot of cost and weight. Those 1/8" cables and their pulleys are going to be around for a long time yet, believe me, and it's not because we don't want electronics, it's because we can't trust them that much. My Power Mechanics teacher in high school told us kids that 90% of all car problems would be electrical, and in those many years since he's been proven right over and over again. Well, as you mentioned, change is going to happen some day. What will change to allow these things to happen? It most likely will not be new materials. Faults in electronics are generally due bad design of the system, not the components themselves. What will have changed when the day comes where you can trust the system? [snipped] * * * * * *Stop dreaming about alternate propulsion methods and fancy FBW systems and go invent and build them and if they make sense they'll sell and you'll become rich and famous. Aviation is as market- driven as anything else, and we're not resistant to innovation that saves us money or makes us safer. But we WON'T buy something that doesn't work as well as what we have now. Period. Well, something that makes sense would be something that is lighter, cheaper, easier to fix, etc than what we have, which would mean it would be imprudent, to say, spend $50,000 on a base plane, and add a $5000 of extra equipment to it. That would not make sense. In any case, my focus is only in the propulsion system. If that failed, there would be no point for me, personally, to continue, as it is very difficult, if not impossible, to improve upon the tractor model to satisfy requirements outlined by CAFE/PAV. -Le Chaud Lapin- |
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