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#101
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Mechanics of Elevator Trim. In Detail.
On Jun 15, 9:42 pm, Le Chaud Lapin wrote:
On Jun 15, 3:30 pm, wrote: On Jun 9, 12:36 pm, Le Chaud Lapin wrote: On Jun 9, 1:19 pm, Gig 601Xl Builder You never learned of trim until MSFS and you are going to design an airplane. Fabulous! Is it really necessary to understand the particular way it was done in C172 to achieve the same result? The same thing could be achieved using more electronics, less mechanics, and the controls might be entirely different. #1. Learn to fly first. #2. Study the construction of aircraft, best done by taking an aircraft maintenance course. I think the difference here is that I am not looking for something evolutionary. I think that is a dead-end road. There is so much in the world to learn, that if a researcher were to take this approach to every attempt to advance a field, breakthroughs would hardly occur. In fact, I think it is precisely this mentality that makes the current process not as fruitful as it could be. Perhaps the epitome of this type of thinking can be seen on the first page of this site: http://www.roadabletimes.com/ Question: "How does one make a flying car?" Answer: "One could start by taking a car and putting wings on it." This is silly, and it is obvious to everyone now that it is silly, but to at least one individual, it was not. That man spent countless hours purusing a dream that would never materialize because his approach was fundamentally flawed. Now if one were to take the objectives of CAFE/PAV to make a new type of vehicle: http://www.cafefoundation.org/v2/pav_home.php ..and begin by starting with a "reference" design, that person might share the same fate of he who made the "flying car" of the first link. Some of you think it is foolish to embark upon a research path without having a thorough understanding of what has been done. I think not. I think, in many cases, one can be too familiar with what has been done. Common knowledge does not necessarily liberate the mind. It might stifle it. And if it seems arrogant not to follow the path already tread by great designers, I think it would be even more arrogant, after having studied what the great designers have done, to think that one would make extraordinary advancements beyond what those greats have done, within the same path. True breakthroughs often require a breach of continuity, and significant technological advancement occurs when those breaches occur at semi-regular intervals. A good example is vacuum tubes versus transistors. Absolutely zero knowledge of vacuum tubes is required to understand transistors. There is a bit of ancillary knowledge, like thermodynamics, band-theory, and electrodynamics that is immediately transferrable from vacuum tube theory to transitor theory, but knowlege of vacuum tubes themselves is inessential. But both act as amplifiers. Both essentially accomplish the same thing as elements in a larger system. Now imagine, toward the end of the vacuum tube era, that someone had proposed to make a new type of amplifier that would be better on almost every imaginable axes, but that person had no intention of spending any time studying vacuum tubes. Would it have been necessary to study vacuum tubes? This is essentially what you are saying about PAV's. You are saying that, the best way to proceed is to learn all I can about convential aircraft. Why is that necessary? It presumes that the method by which the objective is accomplish is similar to what has already been done (tractor model, for example). A better approach might be to make no assumptions at all, but focus on the end result, then work backward, evaluating extant technologies (applicable in, say, 2010), keeping a respectible distance from the prevaling models of aicraft design, just as transitor theorist might deliberately keep a respectable distance from vacuum tubes. #3. THEN think about designing an airplane. No worthwhile design that I'm aware of has ever been put forward by someone who was unfamiliar with the way things are now and why they are that way, but I have seen designs built by folks who "knew better" than everyone else. One of those, built by a local guy who would take no constructive criticism of his ideas, stalled at circuit altitude and dropped him, hard, on the surface of the earth. He was such a stubborn guy that he got up and walked away, but he neither built nor flew any more airplanes. Needless to say, this design was neither inspected nor approved nor licensed to any standard whatever. A good way to win is avoid races where number of entrants is 1. It would be extremely hard for someone in my opinion to make notable improvement on existing aircraft design. The world is filled with high skilled, highly trained, thoroughly experience, professional aircraft designers who spent their lifetimes aiming for that extra 5%. Extra 5% is not going to make a PAV, so if there is any chance of succeeding at all, one should avoid paths where best-case scenario is a 5% improvement. Adding electronic controls to something like a trim tab on a lightplane is one of those "better" ideas that has no basis in reality. It adds complexity, which adds failure points and cost and weight, none of which are welcome. I hear a lot of mechanics say this about cars. I think there should be a qualification made thos these types of statments: "It adds complexity, which adds failure points and cost and weight, none of which are welcome, unless the person integrating the electronics is an electrical engineer unperturbed by the idea of adding electronic controls to a mechanical system." It is no more accurate than manual trim. Perhaps not. But a computer will outperform a human 10x to 1x if the goal is to optimize fuel consumption with automatic trim control. There is literally countless scenarios where combination of software/ electronics would far exceed capabilities of a pilot to achieve same objective. As aviation advances, there will be much more employment of electronics and software. I am simply saying, whatever will exist 50 years from now (when many of us will be dead, heheh)...whatever that thing is...start thinking about *that* now, not something that was designed in 1950. -Le Chaud Lapin- The guys who invented the transistor (Brattain and all) understood electricity and were engineers who could design and build electronic devices. That's the equivalent of knowing how to fly and how to build aircraft. They were not new to electronics, they didn't stumble across semiconductors by accident. Solid-state selenium diodes (not to mention crystal diodes) had already been in use by then for some time, and so they built on the knowledge of other folks. Numerous flying cars have been built from scratch, not based on existing automobiles. It's not something new. Molt Taylor's Aerocar (late '40s or early '50s; Google it) was certified and produced in small numbers, but the compromises necessary to achieve flight in a vehicle that also has to fit on the road and operate in traffic mean it's a poor car and a poor airplane, and didn't sell well enough to justify continuing with it. Electronics and computers can't fix the hard limitations of physics. Over the years I've been around aviation I can't recall how many attempts have been made in my own time to build such a machine, and none of them are visible today. It seems that only the naive attempt it, and find out the hard way about compromises that ruin the whole idea. But don't let me discourage you. Maybe some other folks will be spared the grief just be watching you try it. Dan |
#102
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Mechanics of Elevator Trim. In Detail.
On Jun 15, 9:42 pm, Le Chaud Lapin wrote:
On Jun 15, 3:30 pm, wrote: Adding electronic controls to something like a trim tab on a lightplane is one of those "better" ideas that has no basis in reality. It adds complexity, which adds failure points and cost and weight, none of which are welcome. I hear a lot of mechanics say this about cars. I think there should be a qualification made thos these types of statments... A good example of an "improved" system in lightplanes was the electric flaps in 150s and 172s. The old system involved a lever and some cables. The lever was pulled up to 10, 20, 30 or 40 degrees, so the lever was the flap position indicator and the cables were the only other weight involved. The effort to pull the lever up was a point of complaint with some feeble pilots. The electric flap system has a gearmotor driving a jackscrew, microswitches on the jackscrew nut sleeve to limit its travel, a DPDT momentary switch on the panel, a special wirewound potentiometer in the wing to follow the bellcrank to drive a flap position indicator on the panel, and cables and pulleys from the right wing (where the motor is) to the left wing to drive the left flap. So now we have the same cables and pulleys (although a little less of them), a switch that fails regularly (the springs that center it break), and cable bundle whose connectors at the wing roots and flap motor assemble get wet and corrode), microswitches that get oil in them off the jackscrew threads (meaning that sometimes the flaps won't come down, or worse, that they won't retract on a go-around), a five- pound motor and jackscrew (which lowers useful load), a special potentiometer that wears out and costs more than $500 from Cessna and isn't available anywhere else (bought one a few years ago), a flap position indicator that costs $475 (bought one last year), and the loss of the option of raising the flaps right at touchdown to get max weight on the wheels for braking on short strips, which annoyed no end a lot of the bush guys who relied on that feature. At least Cessna left things alone in the 180 and 185, airplane flown by real pilots who didn't mind pulling a lever. You can decide if this was an "improvement." Lots of owners who have had to have this system fixed don't think so. Dan |
#103
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Mechanics of Elevator Trim. In Detail.
On Jun 16, 10:08*am, "Ken S. Tucker" wrote:
On Jun 15, 9:16 pm, Le Chaud Lapin wrote: On Jun 15, 6:34 pm, "Ken S. Tucker" wrote: I concur with Dan on his last two posts, yeah that's rare, but anyway... I designed and tested (models) of a fantastic plane, but when I chose between putting my wife and kids in my fantastic plane or into a proven (safe) C172, I chose the C172. Here's why: If my machine cracked up due to a fault in my design, and killed my family except for me, I'd feel obligated to shoot myself, though I wouldn't. That said, build your machine, put it threw it's paces then take on a passenger, who knows what the tag "EXPERMENTAL" means on the side of the A/C, and have fun. Ken- Perhaps there will not be time in my life to see a design realized, but if I were so fortunate, I would probably do just that...get in it myself first. But before doing that, I would let it fly itself over a desert, since controls would be software anyway. That sounds like a good idea. A 1/4 scale is good, it can be powered by a cheap chainsaw motor. Do you have any general ideas for a lay-out yet? -Le Chaud Lapin- If you lived close by, I'd give you some help. I live in Austin, Texas. Some locals and I have been toying around with the idea of renting a garage for experiments, though I think that is premature. I would rather use something like SolidWorks to create a model to verify that the aircraft would fly first. I do have a vague vision of the form- factor of the aircraft, but as I see it, there are two crucial things that need to be determined before putting both feet in the water: 1. The PAV I envision relies on an unproven, unorthodox hypothesis of the origin of lift. I say concept because there is no weird science involved like anti-gravity machines or anything like that, but if it were to fly, it would require a reaxmination of the prevailing theories. This is the hardest part, and I have been concentrating only on the lift elements. A lot of math and a prototype of certain control surfaces would help. 2. The second problem is a problem that would be faced by any designer of a PAV, and that is the power source. The PAV I envision would have an extremely high reliance on electrial power (the lift engine itself would rely on electrical power), and this is a hard problem. Conventional fuels, in 2008, still appear to be the most pratical approach, even if the fuel is only used to operate a generator. As far as the engine, I cannot say what it is yet, but can say that it doesn't use an ICE. -Le Chaud Lapin- |
#104
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Mechanics of Elevator Trim. In Detail.
On Jun 16, 11:27*am, wrote:
* * * * * The guys who invented the transistor (Brattain and all) understood electricity and were engineers who could design and build electronic devices. That's the equivalent of knowing how to fly and how to build aircraft. They were not new to electronics, they didn't stumble across semiconductors by accident. Solid-state selenium diodes (not to mention crystal diodes) had already been in use by then for some time, and so they built on the knowledge of other folks. There are certain pieces of knowledge that are applicable and certain pieces that are that. That's all I am saying. I know people who studied aero/astro for years and had never designed and airplane, but could if they had to. With regard to transistors, I have only been a a clean room, and I have never operated say, a chemical-vapor deposition (CVD) machine, but I know how it works. The question is essentially: "What knowledge of old is useful to create the new?" A key word in this question is "new", which could be interpreted as "new new" or "incrementally new". Incrementally new is best served by examining state-of-art and making incremental improvement. New new is best served by rethinking from a more fundamental perspective. I contend that, in any field, there is a large percentage of researchers who do not bother thinking about "new new", because they regard it as a fruitless endeavor or too risky. But sooner or later, "new new" reveals itself, and the cylce repeats. * * * * * Numerous flying cars have been built from scratch, not based on existing automobiles. It's not something new. Molt Taylor's Aerocar (late '40s or early '50s; Google it) I have link on my ready-access favorites of web browser: http://www.roadabletimes.com/ so yes I have seen it, and many others. Not to criticize this design, but there is no way I would ever make a flying car that looks like that. Each time I see someone who has passion for making flying car take car and mount airplane on top of it, I feel sorry for them - so much passion... was certified and produced in small numbers, but the compromises necessary to achieve flight in a vehicle that also has to fit on the road and operate in traffic mean it's a poor car and a poor airplane, and didn't sell well enough to justify continuing with it. Electronics and computers can't fix the hard limitations of physics. Over the years I've been around aviation I can't recall how many attempts have been made in my own time to build such a machine, and none of them are visible today. It seems that only the naive attempt it, and find out the hard way about compromises that ruin the whole idea. I have noticed that a lot of people making flying cars have an incredible urge to "just get something working", with the expectation that , if it "works", it can be improved with tweaks over time. This is a dangerous approach. As you noted, one typically ends up with something of questionable design that enjoys, at best, a lukewarm reception. * * * * *But don't let me discourage you. Maybe some other folks will be spared the grief just be watching you try it. Heheh. -Le Chaud Lapin- |
#105
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Mechanics of Elevator Trim. In Detail.
On Jun 16, 11:42*am, wrote:
On Jun 15, 9:42 pm, Le Chaud Lapin wrote: On Jun 15, 3:30 pm, wrote: * * * * *Adding electronic controls to something like a trim tab on a lightplane is one of those "better" ideas that has no basis in reality. It adds complexity, which adds failure points and cost and weight, none of which are welcome. I hear a lot of mechanics say this about cars. *I think there should be a qualification made thos these types of statments... * * * A good example of an "improved" system in lightplanes was the electric flaps in 150s and 172s. The old system involved a lever and some cables. The lever was pulled up to 10, 20, 30 or 40 degrees, so the lever was the flap position indicator and the cables were the only other weight involved. The effort to pull the lever up was a point of complaint with some feeble pilots. * * * The electric flap system has a gearmotor driving a jackscrew, microswitches on the jackscrew nut sleeve to limit its travel, a DPDT momentary switch on the panel, a special wirewound potentiometer in the wing to follow the bellcrank to drive a flap position indicator on the panel, and cables and pulleys from the right wing (where the motor is) to the left wing to drive the left flap. * * So now we have the same cables and pulleys (although a little less of them), a switch that fails regularly (the springs that center it break), and cable bundle whose connectors at the wing roots and flap motor assemble get wet and corrode), microswitches that get oil in them off the jackscrew threads (meaning that sometimes the flaps won't come down, or worse, that they won't retract on a go-around), a five- pound motor and jackscrew (which lowers useful load), a special potentiometer that wears out and costs more than $500 from Cessna and isn't available anywhere else (bought one a few years ago), a flap position indicator that costs $475 (bought one last year), and the loss of the option of raising the flaps right at touchdown to get max weight on the wheels for braking on short strips, which annoyed no end a lot of the bush guys who relied on that feature. At least Cessna left things alone in the 180 and 185, airplane flown by real pilots who didn't mind pulling a lever. * * * You can decide if this was an "improvement." Lots of owners who have had to have this system fixed don't think so. This is an excellent anecdote. It illustrates something I tried to point out in another post a few months ago: No potentiometer should cost $500. If it is used to make sure the Queen of England does not slip and fall while walking down a steep flight of stairs, it should still not cost $500. This same phenomenon is present today. I have a bunch of aviataion related newspapers and magazines that I read see parts and what they cost. I look especially at electronics parts. The prices are outrageous. Whatever the excuses - regulation, low-volume - these prices are simply ridiculous. In many cases, the exact same product is sold in a different consumer context for a 40% mark-up. There is rigidity of innovation in the entire aviation industry. Much of the technology really is 50 years old. New technology is integrated in patchwork fashion at a sloth's pace. There are many places where metal is used but plastic would be just as good, but plastic cannot be used because the designer insists on adding plastic incrementally. Much of the new technology's benefit is only realized when gross re- examination of the design of the system is permitted. Otherwise one ends up with a $200,000 aircraft with a 90% cost-reduction on a part that originally cost $400, making new cost $199,960. What good is that? This is why I see opportunity. Electrical, and especially software engineers, have great opportunity to eliminate mechanized control in aviation (and many other industries for that matter). But as implied by your anecdote, it should not be done as an afterthought, after months of haggling where the engineering department finally decides to "integrate" more electronics, with foot-dragging, coporate in- fighting, special hiring of disposable engineers skilled in electronics to contribute to a system that is fundamentally regarded by the old guard as mechanical...it should be done in context where the engineering team is _fundamentally_ predisposed to employ software and electronics at low-cost throughout. I thought http://www.terrafugia.com was a team, filled with bunch of MIT grads, that might take this approach, but they themselves stated in one article that they would refrain from going after the Big-Kill, meaning pervasive software systems throughout. I think this is unfortunate. -Le Chaud Lapin- |
#106
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Mechanics of Elevator Trim. In Detail.
On Jun 16, 12:33 pm, Le Chaud Lapin wrote:
This same phenomenon is present today. I have a bunch of aviataion related newspapers and magazines that I read see parts and what they cost. I look especially at electronics parts. The prices are outrageous. Whatever the excuses - regulation, low-volume - these prices are simply ridiculous. In many cases, the exact same product is sold in a different consumer context for a 40% mark-up. Regulation, and the risk of liability, makes all aircraft stuff expensive. That's not the manufacturer's or designer's fault; that's OUR fault, those of us who choose to rent or buy airplanes and proceed to do stupid things with them and get ourselves killed or maimed, whereupon the manufacturer is sued for many millions because his product was "defective." Defective because it could not protect me from my own stupidity. And juries swallow this. Besides that, the low production numbers make these things more expensive. As far as a different lift process, man has been using what Nature perfected a long time ago: the airfoils as used by birds, controlled by tails as used by birds. Flapping-wing technology still hasn't been figured out but someone will do it soon, although it guarantees a rough ride. If you want a different lift system, check out the bumblebee. There's something related to spanwise vortex lift going on there, and the guys who have had deep-stall crashes in canards (notably the Velocity) have had some experience with it. Lots of lift generated at well below stall speeds with an unexpectedly low sink rate. Sometimes it's a survivable crash. There's potential there. Dan |
#107
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Mechanics of Elevator Trim. In Detail.
In rec.aviation.student Le Chaud Lapin wrote:
On Jun 16, 11:27?am, wrote: ? ? ? ? ? The guys who invented the transistor (Brattain and all) understood electricity and were engineers who could design and build electronic devices. That's the equivalent of knowing how to fly and how to build aircraft. They were not new to electronics, they didn't stumble across semiconductors by accident. Solid-state selenium diodes (not to mention crystal diodes) had already been in use by then for some time, and so they built on the knowledge of other folks. There are certain pieces of knowledge that are applicable and certain pieces that are that. That's all I am saying. I know people who studied aero/astro for years and had never designed and airplane, but could if they had to. I'm sure they could design a *bad* airplane. Designing a good one takes experience, not just theoretical knowledge. With regard to transistors, I have only been a a clean room, and I have never operated say, a chemical-vapor deposition (CVD) machine, but I know how it works. That's miles away from being able to actually invent them from scratch. The question is essentially: "What knowledge of old is useful to create the new?" A key word in this question is "new", which could be interpreted as "new new" or "incrementally new". Incrementally new is best served by examining state-of-art and making incremental improvement. New new is best served by rethinking from a more fundamental perspective. I contend that, in any field, there is a large percentage of researchers who do not bother thinking about "new new", because they regard it as a fruitless endeavor or too risky. But sooner or later, "new new" reveals itself, and the cylce repeats. I contend that "new new" simply does not exist. *All* advances are incremental. To the extent that any advance appears to be revolutionary, it is only because its predecessors are not widely known. A great example of this is the transistor. To the general public, it looks like this great sudden flash of innovation. Looking at the actual history of the field, it was the culmination of years of incremental advances. If you think I'm wrong, I'd love to see some counterexamples. Especially if you can give counterexamples which not only were not incremental, but which were invented by someone who was not already an expert in the field. -- Mike Ash Radio Free Earth Broadcasting from our climate-controlled studios deep inside the Moon |
#108
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Mechanics of Elevator Trim. In Detail.
On Jun 16, 9:43*pm, Michael Ash wrote:
In rec.aviation.student Le Chaud Lapin wrote: A key word in this question is "new", which could be interpreted as "new new" or "incrementally new". *Incrementally new is best served by examining state-of-art and making incremental improvement. *New new is best served by rethinking from a more fundamental perspective. *I contend that, in any field, there is a large percentage of researchers who do not bother thinking about "new new", because they regard it as a fruitless endeavor or too risky. *But sooner or later, "new new" reveals itself, and the cylce repeats. I contend that "new new" simply does not exist. *All* advances are incremental. To the extent that any advance appears to be revolutionary, it is only because its predecessors are not widely known. There is no such thing as quantized progress in technology of course. Anything that looks like a wheel can be traced back 1000's of years. "New new" is a relative concept. One must assess how new is is the new new relative to what others consider to be the state-of-the-art at the time. A great example of this is the transistor. To the general public, it looks like this great sudden flash of innovation. Looking at the actual history of the field, it was the culmination of years of incremental advances. That brings another point. Conception and perfection of the new cannot be an instantaneous act. Development of the new occurs over time. So again, newness must be considered within the context of the state of the art. For example, if a new PAV were created, in 2008, that satisfied the challenges put forth by CAFE, one could always claim that its design builds upon the work of others, even though the general public might regard it as a technological breakthrough: http://www.cafefoundation.org/v2/pav_home.php 1. Fully glass cockpit? Not new, the LCD's come from ViewSonic, and has been done already anyway. 2. Software-controlled autostabilization? Not new. Uses long history of PID and other control theory. Other aircraft do it. 3. Electric generator? Not new at all, on an airplane, or otherwise. 4. Vertical Take-Off & Landing? Old concept. Other aircraft do it. 5. Side-mounted joystick controls instead of a yoke? Not new. Many aircraft have them. 6. Elimination of foot-pedals? Done already. 7. New means of lift? (no comment..heheh) 8. Elimination of mechanical controls? Not new. 9. Ultra-quiet? Not new. Other aircraft have been made to be ultra- quiet. You get the point. With sufficient argument, everthing new can be seen as old. Even with transistors, one could argue that sand has been here since very early days of earth, and to some extent, were conducting long before scientists discovered semiconduction. Determining whether something is evolutionary versus revolutionary is inherently subjective, making the truth thereof vulnerable to the prejudices of the obvservers. Because we have no omniscient being willing to serve as impartial judge, another path to objectivity must be found. Strangely, one of the best places to look is toward those who have no familiarity at all with the intricacies of the subject. Then, if the criteria of CAFE for a PAV were satisfied, atomically and simultaneously, for a total cost of say $50,000, we might not regard it as a revolutionary step, but the general public would. So revolutionary design, by definition, has a temporal element. The designer cannot claim revolution if the features of the new are disseminated in a diarrhetic mode where the period of presentation is so long that the observers become bored with progress. A revolutionary system requires the simultaneous application of many advanced concepts, across technological disciplines, at once. If you think I'm wrong, I'd love to see some counterexamples. Especially if you can give counterexamples which not only were not incremental, but which were invented by someone who was not already an expert in the field. Hah..tempting, but as mentioned, no matter what I name, the contraption could always be regarded as evolutionary. Nevertheless, the notion that revolutionary ideas exist, even though they are inextricably evolutionary, still prevails. Here is an example from NASA: http://www.nasa.gov/home/hqnews/2005..._concepts.html -Le Chaud Lapin- |
#109
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Mechanics of Elevator Trim. In Detail.
On Jun 16, 10:55 am, Le Chaud Lapin wrote:
On Jun 16, 10:08 am, "Ken S. Tucker" wrote: On Jun 15, 9:16 pm, Le Chaud Lapin wrote: On Jun 15, 6:34 pm, "Ken S. Tucker" wrote: I concur with Dan on his last two posts, yeah that's rare, but anyway... I designed and tested (models) of a fantastic plane, but when I chose between putting my wife and kids in my fantastic plane or into a proven (safe) C172, I chose the C172. Here's why: If my machine cracked up due to a fault in my design, and killed my family except for me, I'd feel obligated to shoot myself, though I wouldn't. That said, build your machine, put it threw it's paces then take on a passenger, who knows what the tag "EXPERMENTAL" means on the side of the A/C, and have fun. Ken- Perhaps there will not be time in my life to see a design realized, but if I were so fortunate, I would probably do just that...get in it myself first. But before doing that, I would let it fly itself over a desert, since controls would be software anyway. That sounds like a good idea. A 1/4 scale is good, it can be powered by a cheap chainsaw motor. Do you have any general ideas for a lay-out yet? -Le Chaud Lapin- If you lived close by, I'd give you some help. I live in Austin, Texas. I'm currently near Vernon BC. Some locals and I have been toying around with the idea of renting a garage for experiments, though I think that is premature. I would rather use something like SolidWorks to create a model to verify that the aircraft would fly first. I do have a vague vision of the form- factor of the aircraft, but as I see it, there are two crucial things that need to be determined before putting both feet in the water: 1. The PAV I envision relies on an unproven, unorthodox hypothesis of the origin of lift. I say concept because there is no weird science involved like anti-gravity machines or anything like that, but if it were to fly, it would require a reaxmination of the prevailing theories. This is the hardest part, and I have been concentrating only on the lift elements. A lot of math and a prototype of certain control surfaces would help. Perhaps a rotary wing? 2. The second problem is a problem that would be faced by any designer of a PAV, and that is the power source. The PAV I envision would have an extremely high reliance on electrial power (the lift engine itself would rely on electrical power), and this is a hard problem. Conventional fuels, in 2008, still appear to be the most pratical approach, even if the fuel is only used to operate a generator. Interesting, electrics have made good advances, maybe regenerative braking during descent such as some vehicles use while going down hill. Solar cells on the top of the wings are proven practical to keep the batteries up to full charge while sitting on the ground. As far as the engine, I cannot say what it is yet, but can say that it doesn't use an ICE. Mean, Green and Lean! Ken |
#110
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Mechanics of Elevator Trim. In Detail.
On Jun 17, 12:57*am, "Ken S. Tucker" wrote:
On Jun 16, 10:55 am, Le Chaud Lapin wrote: On Jun 16, 10:08 am, "Ken S. Tucker" wrote: On Jun 15, 9:16 pm, Le Chaud Lapin wrote: On Jun 15, 6:34 pm, "Ken S. Tucker" wrote: I concur with Dan on his last two posts, yeah that's rare, but anyway... I designed and tested (models) of a fantastic plane, but when I chose between putting my wife and kids in my fantastic plane or into a proven (safe) C172, I chose the C172. Here's why: If my machine cracked up due to a fault in my design, and killed my family except for me, I'd feel obligated to shoot myself, though I wouldn't. That said, build your machine, put it threw it's paces then take on a passenger, who knows what the tag "EXPERMENTAL" means on the side of the A/C, and have fun. Ken- Perhaps there will not be time in my life to see a design realized, but if I were so fortunate, I would probably do just that...get in it myself first. But before doing that, I would let it fly itself over a desert, since controls would be software anyway. That sounds like a good idea. A 1/4 scale is good, it can be powered by a cheap chainsaw motor. Do you have any general ideas for a lay-out yet? -Le Chaud Lapin- If you lived close by, I'd give you some help. I live in Austin, Texas. I'm currently near Vernon BC. Some locals and I have been toying around with the idea of renting a garage for experiments, though I think that is premature. I would rather use something like SolidWorks to create a model to verify that the aircraft would fly first. I do have a vague vision of the form- factor of the aircraft, but as I see it, there are two crucial things that need to be determined before putting both feet in the water: 1. The PAV I envision relies on an unproven, unorthodox hypothesis of the origin of lift. I say concept because there is no weird science involved like anti-gravity machines or anything like that, but if it were to fly, it would require a reaxmination of the prevailing theories. *This is the hardest part, and I have been concentrating only on the lift elements. *A lot of math and a prototype of certain control surfaces would help. Perhaps a rotary wing? Hah...I realized two nights ago before going to bed that the form of the airfoils about the aircraft is essentially unlimited. What is really important is understanding why there is a net upward force on the airfoil. Once that is understood, the sky is the limit. I have purposely refrained from imagining all the different forms of airfoils for the time being. It would only use brain cycles I must research for tedious problems in number theory at present. But my guess is that the airfoil forms could range from a bland planar to the ultra- exotic. And yes, the standard rotary wing might be a component. 2. The second problem is a problem that would be faced by any designer of a PAV, and that is the power source. The PAV I envision would have an extremely high reliance on electrial power (the lift engine itself would rely on electrical power), and this is a hard problem. Conventional fuels, in 2008, still appear to be the most pratical approach, even if the fuel is only used to operate a generator. Interesting, electrics have made good advances, maybe regenerative braking during descent such as some vehicles use while going down hill. Solar cells on the top of the wings are proven practical to keep the batteries up to full charge while sitting on the ground. Does not hurt, if the weight problem can be eliminated. As far as the engine, I cannot say what it is yet, but can say that it doesn't use an ICE. Mean, Green and Lean! Green is definitely an objective. Electronics is the way to move forward. I was looking at the the Honda Clarity FCX today. http://en.wikipedia.org/wiki/Honda_FCX_Clarity Apparently they were able to get the size of fuel cell to that of chassis of desktop computer. -Le Chaud Lapin- |
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