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#1
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Sitting around the hanger and discussing the possibility of somehow using
off-the-shelf electronic/computer components or gadgits for semi-automatic wing leveling on lightly loaded, short wingspans. Not being computer guys, the current thought is that something should be out there that is available cheaply and modifiable to use a simple wing leveler. Having heard someplace that automotive computers, as an example, sense data millions of times leads us to believe that sensing the wing tip initial movement and counteracting very very quickly would be a good thing. As an example: One fellow pictured a rolling ball bearing inside a tube somehow activating a magnetic switch which in turn pulses a dc linear motor to operate the aileron minutely. We are not sure how to detect the very earliest initial wing tip movement or drive the small trim type motor and would appreciate some thoughts or site recommendations to investigate. Thanks, Dick |
#2
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![]() "Dick" wrote Sitting around the hanger and discussing the possibility of somehow using off-the-shelf electronic/computer components or gadgits for semi-automatic wing leveling on lightly loaded, short wingspans. As an example: One fellow pictured a rolling ball bearing inside a tube somehow activating a magnetic switch which in turn pulses a dc linear motor to operate the aileron minutely. We are not sure how to detect the very earliest initial wing tip movement or drive the small trim type motor and would appreciate some thoughts or site recommendations to investigate. Hmmmm. No free (or even cheap) lunch, here. The idea of a ball bearing in a tube is not even close. Ever hear of the graveyard spiral? It is what killed Kennedy. (not the president) In such a spiral, you experience several 360 degree turns, diving steeply enough that vertical descent rates of 10,000 feet per minute (if the plane holds together) are possible. Still, the ball in the tube would stay right in the middle. One G all the way. You need a gyroscope, or an electronic equivalent. Some have played using very sensitive GPS antennae in the wingtips. Best advice? Trim the plane, stay awake and fly it, or BUY an autopilot, or wing leveler. Or google wing leveler. -- Jim in NC |
#3
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("Morgans" wrote)
snips We are not sure how to detect the very earliest initial wing tip movement or drive the small trim type motor and would appreciate some thoughts or site recommendations to investigate. The idea of a ball bearing in a tube is not even close. Ever hear of the graveyard spiral? It is what killed Kennedy. (not the president) In such a spiral, you experience several 360 degree turns, diving steeply enough that vertical descent rates of 10,000 feet per minute (if the plane holds together) are possible. Still, the ball in the tube would stay right in the middle. One G all the way. You need a gyroscope, or an electronic equivalent. Some have played using very sensitive GPS antennae in the wingtips. Best advice? Trim the plane, stay awake and fly it, or BUY an autopilot, or wing leveler. Or google wing leveler. Automotive world is using electronic stability-control (ESC) systems with documented success. The article says the system used a decade ago wasn't very good, but they've come a long way since then. http://www.detnews.com/2005/autoscon.../F01-91164.htm http://www.caranddriver.com/idealbb/...?topicID=60884 I'm guessing some variant of this is what you'll eventually cobble together in your garage. Montblack |
#4
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![]() "Montblack" wrote Automotive world is using electronic stability-control (ESC) systems with documented success. I'm guessing some variant of this is what you'll eventually cobble together in your garage. More than likely, they are using piezzo electric rate sensors for the direction information. They are relatively cheap, and do well at sensing rapid changes. They have been used for a while in the RC airplane world, as a stability aid, with good success, also. Any really stable electronic gyro system in the commercial auto-pilots world, are much more expensive, and as far as I know, not available to the public. Problem is, piezzo sensors have a fairly fast "drift." which makes the leveling ability good only for a few seconds. If you handed over control to one of these units, within 30 seconds, you would be upside down, and the unit would think everything is still OK. In the RC world, if the plane makes a sudden move to go upside down, it senses the sudden move and if the sticks have not commanded the sudden move, it will move the control surfaces to stay right side up. It counts on you keeping it somewhat upright, and recalibrates itself often - based on your MarkII eyeballs telling the plane to fly level. Same thing with the car unit in the links. It knows that you are going straight, or following curves. (still reasonably slow changes compared to sudden loss of control) It continually reminds itself that it is going straight, and re-sets itself. Only when a real sudden move is made, does it correctly sense that it is not going straight and the steering wheel wants the car to go straight. The computer then makes corrections to keep the car straight. If a plane wing leveler were based only on these units, and the plane started banking very slowly, the sensor would not realize it. That is the drift. It would re-set as level, then the plane banks another slow degree, and the unit re-sets, and the plane banks...you get the picture. I believe the concoction that had some success, was a GPS wingtip differential altitude sensor. It used these rate sensors in unison to help backup the control movements and make the controls smooth. The units re-set using the GPS info as the reality of what was level. You have to use something (MarkII eyeballs or GPS) doing this. Good luck to the OP, figuring out a homemade wing leveler. It is a tough problem. -- Jim in NC |
#5
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Thanks for everyones input.
Our group was discussing flying in VFR only (no IMC or IFR) and wing leveler only with respect to roll sensitivity of lightly wing loaded, short wing spanned experimentals. Trying to make summer flying in chop somewhat easier. We didn't plan on turning over controls to the device and would still keep a light grip on the stick; just wouldn't have to constantly play the stick. Although we had the impression that a heavier plane would be more stable in chop and require less than continual input by stick, that wasn't much of an option G. Although not discussed among us, I wonder if an increased dihedral result is possible without actually increasing it physically.. Still would appreciate a little discussion that I can pass on for the next non-flying day. Thanks, Dick "Morgans" wrote in message ... "Montblack" wrote Automotive world is using electronic stability-control (ESC) systems with documented success. I'm guessing some variant of this is what you'll eventually cobble together in your garage. More than likely, they are using piezzo electric rate sensors for the direction information. They are relatively cheap, and do well at sensing rapid changes. They have been used for a while in the RC airplane world, as a stability aid, with good success, also. Any really stable electronic gyro system in the commercial auto-pilots world, are much more expensive, and as far as I know, not available to the public. Problem is, piezzo sensors have a fairly fast "drift." which makes the leveling ability good only for a few seconds. If you handed over control to one of these units, within 30 seconds, you would be upside down, and the unit would think everything is still OK. In the RC world, if the plane makes a sudden move to go upside down, it senses the sudden move and if the sticks have not commanded the sudden move, it will move the control surfaces to stay right side up. It counts on you keeping it somewhat upright, and recalibrates itself often - based on your MarkII eyeballs telling the plane to fly level. Same thing with the car unit in the links. It knows that you are going straight, or following curves. (still reasonably slow changes compared to sudden loss of control) It continually reminds itself that it is going straight, and re-sets itself. Only when a real sudden move is made, does it correctly sense that it is not going straight and the steering wheel wants the car to go straight. The computer then makes corrections to keep the car straight. If a plane wing leveler were based only on these units, and the plane started banking very slowly, the sensor would not realize it. That is the drift. It would re-set as level, then the plane banks another slow degree, and the unit re-sets, and the plane banks...you get the picture. I believe the concoction that had some success, was a GPS wingtip differential altitude sensor. It used these rate sensors in unison to help backup the control movements and make the controls smooth. The units re-set using the GPS info as the reality of what was level. You have to use something (MarkII eyeballs or GPS) doing this. Good luck to the OP, figuring out a homemade wing leveler. It is a tough problem. -- Jim in NC |
#6
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Dick,
I think that winglets would improve roll stability, and L/D, climb performance and high alt. performance. Jan Carlsson www.jcpropellerdesign.com "Dick" skrev i meddelandet m... Thanks for everyones input. Our group was discussing flying in VFR only (no IMC or IFR) and wing leveler only with respect to roll sensitivity of lightly wing loaded, short wing spanned experimentals. Trying to make summer flying in chop somewhat easier. We didn't plan on turning over controls to the device and would still keep a light grip on the stick; just wouldn't have to constantly play the stick. Although we had the impression that a heavier plane would be more stable in chop and require less than continual input by stick, that wasn't much of an option G. Although not discussed among us, I wonder if an increased dihedral result is possible without actually increasing it physically.. Still would appreciate a little discussion that I can pass on for the next non-flying day. Thanks, Dick "Morgans" wrote in message ... "Montblack" wrote Automotive world is using electronic stability-control (ESC) systems with documented success. I'm guessing some variant of this is what you'll eventually cobble together in your garage. More than likely, they are using piezzo electric rate sensors for the direction information. They are relatively cheap, and do well at sensing rapid changes. They have been used for a while in the RC airplane world, as a stability aid, with good success, also. Any really stable electronic gyro system in the commercial auto-pilots world, are much more expensive, and as far as I know, not available to the public. Problem is, piezzo sensors have a fairly fast "drift." which makes the leveling ability good only for a few seconds. If you handed over control to one of these units, within 30 seconds, you would be upside down, and the unit would think everything is still OK. In the RC world, if the plane makes a sudden move to go upside down, it senses the sudden move and if the sticks have not commanded the sudden move, it will move the control surfaces to stay right side up. It counts on you keeping it somewhat upright, and recalibrates itself often - based on your MarkII eyeballs telling the plane to fly level. Same thing with the car unit in the links. It knows that you are going straight, or following curves. (still reasonably slow changes compared to sudden loss of control) It continually reminds itself that it is going straight, and re-sets itself. Only when a real sudden move is made, does it correctly sense that it is not going straight and the steering wheel wants the car to go straight. The computer then makes corrections to keep the car straight. If a plane wing leveler were based only on these units, and the plane started banking very slowly, the sensor would not realize it. That is the drift. It would re-set as level, then the plane banks another slow degree, and the unit re-sets, and the plane banks...you get the picture. I believe the concoction that had some success, was a GPS wingtip differential altitude sensor. It used these rate sensors in unison to help backup the control movements and make the controls smooth. The units re-set using the GPS info as the reality of what was level. You have to use something (MarkII eyeballs or GPS) doing this. Good luck to the OP, figuring out a homemade wing leveler. It is a tough problem. -- Jim in NC |
#7
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Very difficult to thermal with wing levelers.
Wing leveler suggestion: Take neighbor kid along. Show him how to move stick to keep wings level. Give him stick and tell him you will give him a quarter (whoops, $5 in today's market) to keep wings level. Show him how to keed airspeed with fore and aft movement of stick and tell him to wake you when ground is near. Then take a nap. Take Walkman along so you will not be bothered with the rushing of the wind noise. Good god, why would you want to put a wing leveler in the last bastion of flight where the pilot is still a requirement? Colin |
#8
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In an effort not to go too far beyond my own knowledge, I'll avoid detail.
My best recollection, being about twenty years from being current as either a pilot or a technician, is that "wing leveler" is a very missleading term applied to a single axis auto-pilot. Typically, the single axis would be yaw (heading) and would have been accomplished be slaving to either a rate gyro (such as a turn coordinator or turn and slip) and a potentiometer, or a system of an air jet and heated resistors, to provide a correction signal with considerable integration (a/k/a damping or low pass filtering). Although it would seem intuitive to have the wing leveler steer the plane with the rudder and have the dihedral roll the wings, the only systems that I have seen used the ailerons and depended on the vertical stabilizer to keep the resulting yaw within reason. If you are still interested in learning more about how autopilots work, I would suggest trying to obtain some of the factory trianing manuals for the technicians who will work on them. Try Bendix/King, S-Tech, and others. Some books may also be available at college bookstores on booksellers like Borders or Barnes & Noble. "Dick" wrote in message om... Sitting around the hanger and discussing the possibility of somehow using off-the-shelf electronic/computer components or gadgits for semi-automatic wing leveling on lightly loaded, short wingspans. Not being computer guys, the current thought is that something should be out there that is available cheaply and modifiable to use a simple wing leveler. Having heard someplace that automotive computers, as an example, sense data millions of times leads us to believe that sensing the wing tip initial movement and counteracting very very quickly would be a good thing. As an example: One fellow pictured a rolling ball bearing inside a tube somehow activating a magnetic switch which in turn pulses a dc linear motor to operate the aileron minutely. We are not sure how to detect the very earliest initial wing tip movement or drive the small trim type motor and would appreciate some thoughts or site recommendations to investigate. Thanks, Dick |
#9
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![]() "Jan Carlsson" wrote in message ... Dick, I think that winglets would improve roll stability, and L/D, climb performance and high alt. performance. Jan Carlsson At the speeds we fly, winglets do little to nothing. They only become useful at higher speeds. -- Jim in NC |
#10
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Jim,
I disagree. Winglet are most effective at high angles of attack. They significantly improve roll rate and control at low speeds. Their use on several models of sailplanes solved the problem of the wing dropping during the initial takeoff roll. They also decrease the speed at which the wing stalls. Here is a good article that may, for some, be worth reading. http://www.soaridaho.com/Schreder/Te...lets/Masak.htm Wayne http://www.soaridaho.com/Schreder "Morgans" wrote in message ... At the speeds we fly, winglets do little to nothing. They only become useful at higher speeds. -- Jim in NC |
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