If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#21
|
|||
|
|||
Building an electronic Angle of Attack indicator
Yes. It was made by National Semiconductor and you could get it linear or
logarithmic. It was obsoleted by National about fifteen years ago, but there are still a few of them in the pipeline at a pretty hefty price. Jim wrote in message ... Isn't there a voltage-to-LED-bar-graph IC? I seem to remember such a thing. That would make the circuit simple. |
#22
|
|||
|
|||
Building an electronic Angle of Attack indicator
And after all is said and done, we remind ourselves that we are supposed to
be building inexpensive airplanes that look good and fly well. So a vane on a synchro? Sure, we had those on the Boeing 3-holer (7-deuce) at a cost of slightly less than $10k a copy in 1965 dollars. Surplus synchros? Sure, now you are doing a one-off and how to tell another builder how to use another brand of surplus synchro isn't feasible...not to mention the fact that most synchros are set up to use the 115v 3phase power that the Air Force/Boeing is so pleased with. Or a gas tank sender with a big flap on it? Well, that looks like hell, doesn't it? Besides that wirewound pot on the gas gauge needs some REAL FORCE to push it around and consumes a fair amount of current in the process. Or some thermistors inside the pitot? WIthout a little more description you can't tell exactly what the scheme of that is. One thermistor on the inside top of the pitot and one on the inside bottom, each thermistor heated equally (difficult task) and then you hope that the incoming air is laminar and not swirling around? This might be feasible with a little more explanation. Differential pressure sensors? Haven't done the research lately, but the last time I looked Motorola had stopped making the inexpensive variety and I don't know if anybody else picked up that ball. So, let's take it from scratch and think about what the optimum solution for cost, looks, and reliability might be ... and the rotated yaw string is a good idea except for the fact that 95% of the homebuilts are tractors and the prop blast will decalibrate anything we might come up with... Jim |
#23
|
|||
|
|||
Building an electronic Angle of Attack indicator
RST Engineering - JIm wrote:
Yes. It was made by National Semiconductor and you could get it linear or logarithmic. It was obsoleted by National about fifteen years ago, but there are still a few of them in the pipeline at a pretty hefty price. Jim wrote in message ... Isn't there a voltage-to-LED-bar-graph IC? I seem to remember such a thing. That would make the circuit simple. Nope. It's still very much available in the surface mount package. |
#24
|
|||
|
|||
Building an electronic Angle of Attack indicator
"RST Engineering - JIm" wrote in message m... And after all is said and done, we remind ourselves that we are supposed to be building inexpensive airplanes that look good and fly well. Which is a valid reason to step back from AOA and just build a better basic stall warning. Between my aviation and age-induced hearing loss, and the great improvement in even cheap headsets these days, it is a rare day when I actually hear a "pennywhistle" stall warning. A simple gizmo that mixes a warning tone into the intercom audio would be great! Vaughn |
#25
|
|||
|
|||
Building an electronic Angle of Attack indicator
On Sun, 10 May 2009 09:30:02 -0700, "RST Engineering - JIm"
wrote: And after all is said and done, we remind ourselves that we are supposed to be building inexpensive airplanes that look good and fly well. So a vane on a synchro? Sure, we had those on the Boeing 3-holer (7-deuce) at a cost of slightly less than $10k a copy in 1965 dollars. Surplus synchros? Sure, now you are doing a one-off and how to tell another builder how to use another brand of surplus synchro isn't feasible...not to mention the fact that most synchros are set up to use the 115v 3phase power that the Air Force/Boeing is so pleased with. Or a gas tank sender with a big flap on it? Well, that looks like hell, doesn't it? Besides that wirewound pot on the gas gauge needs some REAL FORCE to push it around and consumes a fair amount of current in the process. Or some thermistors inside the pitot? WIthout a little more description you can't tell exactly what the scheme of that is. One thermistor on the inside top of the pitot and one on the inside bottom, each thermistor heated equally (difficult task) and then you hope that the incoming air is laminar and not swirling around? This might be feasible with a little more explanation. Differential pressure sensors? Haven't done the research lately, but the last time I looked Motorola had stopped making the inexpensive variety and I don't know if anybody else picked up that ball. So, let's take it from scratch and think about what the optimum solution for cost, looks, and reliability might be ... and the rotated yaw string is a good idea except for the fact that 95% of the homebuilts are tractors and the prop blast will decalibrate anything we might come up with... Jim Some years back there was a complete discription of a thermistor based system in Sport Aviation. You might contact the research department or whatever they call it. |
#26
|
|||
|
|||
Building an electronic Angle of Attack indicator
By God, you are correct. When my supplier told me in 1999 that the LM3914
was no longer available, they failed to tell me that the LM3914-1 was a direct replacement and very much still in the pipeline, even as the larger 18 pin through-hole DIP package. Thanks for correcting me. Jim "Rip" wrote in message ... RST Engineering - JIm wrote: Yes. It was made by National Semiconductor and you could get it linear or logarithmic. It was obsoleted by National about fifteen years ago, but there are still a few of them in the pipeline at a pretty hefty price. Jim wrote in message ... Isn't there a voltage-to-LED-bar-graph IC? I seem to remember such a thing. That would make the circuit simple. Nope. It's still very much available in the surface mount package. |
#27
|
|||
|
|||
Building an electronic Angle of Attack indicator
RST Engineering - JIm wrote:
And after all is said and done, we remind ourselves that we are supposed to be building inexpensive airplanes that look good and fly well. So a vane on a synchro? Sure, we had those on the Boeing 3-holer (7-deuce) at a cost of slightly less than $10k a copy in 1965 dollars. Surplus synchros? Sure, now you are doing a one-off and how to tell another builder how to use another brand of surplus synchro isn't feasible...not to mention the fact that most synchros are set up to use the 115v 3phase power that the Air Force/Boeing is so pleased with. Or a gas tank sender with a big flap on it? Well, that looks like hell, doesn't it? Besides that wirewound pot on the gas gauge needs some REAL FORCE to push it around and consumes a fair amount of current in the process. Or some thermistors inside the pitot? WIthout a little more description you can't tell exactly what the scheme of that is. One thermistor on the inside top of the pitot and one on the inside bottom, each thermistor heated equally (difficult task) and then you hope that the incoming air is laminar and not swirling around? This might be feasible with a little more explanation. Differential pressure sensors? Haven't done the research lately, but the last time I looked Motorola had stopped making the inexpensive variety and I don't know if anybody else picked up that ball. So, let's take it from scratch and think about what the optimum solution for cost, looks, and reliability might be ... and the rotated yaw string is a good idea except for the fact that 95% of the homebuilts are tractors and the prop blast will decalibrate anything we might come up with... Jim Every aircraft synchro I have ever seen uses 26 VAC 400 hz single phase. I have seen power supplies for them on e-bay for around $25 or so. It's been awhile since I have looked, but they were there. In any event synchro systems don't seem to be sine wave particular so a simple power supply should be easy. If you want cheap aircraft synchros find a shop that repairs jet aircraft. The 1" "peanut" pressure indicators contain a synchro that usually outlasts the internal lighting. I have found them on e-bay also. Compass amplifiers such as used in the C-12 compass system contain a multitude of synchros since they use a gear train to drive several synchros. Vertical scale instruments such as those used on C-141 also contain synchros. I have seen those for sale on e-bay also. Dan, U.S. Air Force, retired |
#28
|
|||
|
|||
Building an electronic Angle of Attack indicator
And after all is said and done, we remind ourselves that we are supposed to be building inexpensive airplanes that look good and fly well. Which is a valid reason to step back from AOA and just build a better basic stall warning. Vaughn =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= AMEN. First learn to fly with competency and K.I.S.S. in mind. If you fly honest inexpensive safe machines and you're and honest pilot, you can grow old without a gadget to stare at whist you forget to fly the plane to an untimely demise. :-) Barnyard BOb - 55 years of licensed powered flight w/o AOA |
#29
|
|||
|
|||
Building an electronic Angle of Attack indicator
RST Engineering - JIm wrote:
By God, you are correct. When my supplier told me in 1999 that the LM3914 was no longer available, they failed to tell me that the LM3914-1 was a direct replacement and very much still in the pipeline, even as the larger 18 pin through-hole DIP package. Thanks for correcting me. Jim "Rip" wrote in message ... RST Engineering - JIm wrote: Yes. It was made by National Semiconductor and you could get it linear or logarithmic. It was obsoleted by National about fifteen years ago, but there are still a few of them in the pipeline at a pretty hefty price. Jim wrote in message ... Isn't there a voltage-to-LED-bar-graph IC? I seem to remember such a thing. That would make the circuit simple. Nope. It's still very much available in the surface mount package. My pleasure. This topic is timely, since I recently built myself a "Lift Reserve Indicator" based on the LM3914 and a Honeywell sensor. Now I'm doing a "true" angle of attack indicator based on the Maxim 4210 multiplier (and an op amp) to correct for airspeed ram pressure. A terrific treatise on the subject (with one inconsequential math error) can be found he http://users.cablemo.net/~jjshultz/sonex/aoa.html Rip |
#30
|
|||
|
|||
Building an electronic Angle of Attack indicator
Ed wrote:
Some years back there was a complete discription of a thermistor based system in Sport Aviation. You might contact the research department or whatever they call it. Might refer to "Electo Fluidic Autopilot" article. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Prop angle of attack vs age | sid | Piloting | 47 | July 13th 08 04:46 PM |
Glider angle of attack indicator by SafeFlight | Bill Daniels | Soaring | 53 | December 20th 07 12:29 PM |
Angle of attack | Bill Daniels | Soaring | 27 | December 19th 07 06:17 AM |
preferrred bank angle indicator? | Matt Herron Jr. | Soaring | 34 | July 10th 06 02:22 PM |
Lift and Angle of Attack | Peter Duniho | Simulators | 9 | October 2nd 03 10:55 PM |