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AOA indicator poll.



 
 
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  #41  
Old May 25th 20, 10:12 PM posted to rec.aviation.soaring
Sci Fi
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Default AOA indicator poll.

If you had two of these, one on each wing-tip, you would also be able to
see on which side the thermal was..

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  #42  
Old May 26th 20, 08:42 AM posted to rec.aviation.soaring
Luc Job[_2_]
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Default AOA indicator poll.

Well, it's probably true... But only for the kind of thermal able to lift your wing, which is a very good indication of where you should turn...

The anatomy of thermals is something strange and complex with many variations... No technical device is giving a right effective solution for the right first turn... But any gadget that others don't have will be very effective in competition even if it doesn't make you fly better...

  #43  
Old May 26th 20, 08:39 PM posted to rec.aviation.soaring
kirk.stant
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Default AOA indicator poll.

Luc,

I'm a big fan of using AOA (ever since my days long ago in F-4s, that relied heavily on AOA!) and would be interested in your instrument. My problem is I fly an LS6 with a small panel and there is absolutely no place to mount such a display. In the past I have tried yaw stings on the sides of the canopy and as you say, they work but are extremely sensitive to yaw (and not in your field of view when thermalling, anyway).

I have thought about how I would like AOA displayed and concluded that what I want is an indication that I am at the optimum thermalling AOA (for the flap setting) and that I am at the correct approach AOA.

When thermalling, once the proper AOA is determined, it is pretty easy to maintain that by reference of the nose position on the horizon, so an occasional check of the AOA indicator would be sufficient. For that I think just 3 lights would be sufficient - Red for too fast, Green for on-speed, and Yellow for too slow (with transitions lighting the adjacent light, while extremes would flash the appropriate light). This could be 3 bright LEDs on top of the panel, or on each side - taking up no panel space. To use, just roll into the turn, slow to the approximate speed you want, check the lights, adjust your AOA until the Green light is on, then stay at that pitch angle/airspeed.

For landing, I would want an aural cue so that I could fly the whole pattern concentrating outside the cockpit. Based on how AOA tones were used in the F-4, as you approached "on-speed" (say 1.3 Vstall) you would get a slow interrupted tone, increasing to a steady medium frequency tone when on-speed.. Too slow and a rapid higher frequency interrupted tone would blend in, transitioning to a steady high frequency tone at the stall. This could be setup to only come on when the landing gear (or air brakes) was extended, cutting out any vario tones to avoid confusion.

Once used to an audio AOA system, it becomes extremely easy to fly a pattern without ever looking at the airspeed, adjusting nose position as needed to maintain the desired AOA by how the tones change.

Anyway, put me down as seriously interested in your AOA system, probably as a full device (option 3, I believe).

Cheers,

Kirk
66

  #44  
Old May 27th 20, 12:29 AM posted to rec.aviation.soaring
Luc Job[_2_]
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Default AOA indicator poll.


Hi Kirk!

I will within days put the website online... You will have the opportunity to upload a picture of your panel... Maybe it's not hopeless...

I really don't like to have a led directly in front of my eye... that's why I designed an indirect display with a reflector and 5 leds, but this is easy to adapt to any other led display: there is 2 options: you can control up to 5 discrete leds, or any 3-wire or 4-wire led strip with any number of RGB or RGBW leds... Only the software needs to be adapted.

I'm relatively more skeptical about the audio AoA in approach for a simple reason: Gliders have low wing loading (compared to jet fighters, not to paragliders...) and this makes these beasts quite more sensitive to gusts and turbulence... And this will make your AoA much less stable in these conditions... Maybe I'm biased by the fact that I fly mostly in mountains where conditions are generally windy and gusty, at least when it's interesting to fly... So you won't be really able to get a constant tone... The goal looks more like dynamically counteracting the AoA variation due to the turbulence and for this the up-down movement on the indicator is a faster signal than the changing tone... But it doesn't look very complex to add an audio amp in a next version of the system to be able to generate sound instead of cutting the audio... And this can easily be coupled with the landing gear extension to switch from one mode to the other...

Cheers

  #45  
Old May 27th 20, 02:45 AM posted to rec.aviation.soaring
kirk.stant
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Default AOA indicator poll.

On Tuesday, May 26, 2020 at 6:29:06 PM UTC-5, Luc Job wrote:
Hi Kirk!

I will within days put the website online... You will have the opportunity to upload a picture of your panel... Maybe it's not hopeless...

I really don't like to have a led directly in front of my eye... that's why I designed an indirect display with a reflector and 5 leds, but this is easy to adapt to any other led display: there is 2 options: you can control up to 5 discrete leds, or any 3-wire or 4-wire led strip with any number of RGB or RGBW leds... Only the software needs to be adapted.

I'm relatively more skeptical about the audio AoA in approach for a simple reason: Gliders have low wing loading (compared to jet fighters, not to paragliders...) and this makes these beasts quite more sensitive to gusts and turbulence... And this will make your AoA much less stable in these conditions... Maybe I'm biased by the fact that I fly mostly in mountains where conditions are generally windy and gusty, at least when it's interesting to fly... So you won't be really able to get a constant tone... The goal looks more like dynamically counteracting the AoA variation due to the turbulence and for this the up-down movement on the indicator is a faster signal than the changing tone... But it doesn't look very complex to add an audio amp in a next version of the system to be able to generate sound instead of cutting the audio... And this can easily be coupled with the landing gear extension to switch from one mode to the other...

Cheers


Hi Luc,

You have a good point about the difference between low wingloading/high aspect ratio and high wingloading/low aspect ratio wings and AOA. So I will have to see how your approach works! Looking forward to your instrument; looking at my panel I may be able to squeeze it in between my varios.

Cheers,

Kirk
66
  #46  
Old May 31st 20, 11:12 AM posted to rec.aviation.soaring
Luc Job[_2_]
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Posts: 22
Default AOA indicator poll.

One last thing I will probably integrate is a tunable damping factor for the indicator.

The system produce about 600 values/second... I'm computing a first order estimate of the present AoA value based on the x preceding values, this is scientifically more accurate than a simple average and doesn't overload the cpu... Presently my setup is based on 10 values which makes the indicator quite reactive, but it is quite easy to program the software to have this adjustable.

3 positions should be sufficient, but we have 5 leds... So I plan to make tests and see what could be the suitable range. One short pulse on the button will let you choose the damping factor with the rotary knob...

Maybe one reason to keep it on the panel... Or not. It is plugged with a miniature connector on the PCB, so you can also simply use it for calibration, light intensity and damping factor tuning, and unplug it once you're happy... It will ship with a long cable.

PCB & hardware ordered...
  #47  
Old May 31st 20, 03:57 PM posted to rec.aviation.soaring
[email protected]
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Posts: 245
Default AOA indicator poll.

I'm computing a first order estimate of the present AoA value based on the x preceding values, this is scientifically more accurate than a simple average and doesn't overload the cpu... Presently my setup is based on 10 values which makes the indicator quite reactive, but it is quite easy to program the software to have this adjustable.

Sounds great, not sure if it would work better to filter the raw sensor values or the computed AOA.

Also maybe could get by with an IIR running in Int32's.

Xavg += (Newsamp - Xavg) k; // maybe k=3 for short up to k=8 for long

Looking forward to having h/w. Starting to think about how to add the new ports with the nose release.
  #48  
Old June 1st 20, 04:01 AM posted to rec.aviation.soaring
[email protected]
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Default AOA indicator poll.

Or keep the measurement lsb's?

Xavg += Newsamp - (Xavg k); // maybe k=3 for short up to k=8 for long
Dispval = Xavg k;
  #49  
Old June 9th 20, 10:38 AM posted to rec.aviation.soaring
Luc Job[_2_]
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Posts: 22
Default AOA indicator poll.

I got the PCB's yesterday...

And I've put some pictures of the probe hole setup on my DG on the Google album: https://bit.ly/aoaindicator

Too bad that the stencil is still missing... It comes in a separate parcel which takes a different way than the other one...

Next step will be to solder 1-2 circuits and test on other gliders.

I'm exploring different ways to display the most likely present value of the AOA, based on the 'past' values and filtered for turbulence... This is more for scientific reason than necessity... The 0.1 second average I've used last year is not a bad estimate and has proved to be very useable.

I'm setting up a logger to record individual values in order to have a better idea on what it looks like...

But no flyable conditions forecasted in the next days...

Cheers,

Luc
  #50  
Old June 10th 20, 03:44 PM posted to rec.aviation.soaring
Matt Herron Jr.
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Default AOA indicator poll.

On Tuesday, June 9, 2020 at 2:38:43 AM UTC-7, Luc Job wrote:
I got the PCB's yesterday...

And I've put some pictures of the probe hole setup on my DG on the Google album: https://bit.ly/aoaindicator

Too bad that the stencil is still missing... It comes in a separate parcel which takes a different way than the other one...

Next step will be to solder 1-2 circuits and test on other gliders.

I'm exploring different ways to display the most likely present value of the AOA, based on the 'past' values and filtered for turbulence... This is more for scientific reason than necessity... The 0.1 second average I've used last year is not a bad estimate and has proved to be very useable.

I'm setting up a logger to record individual values in order to have a better idea on what it looks like...

But no flyable conditions forecasted in the next days...

Cheers,

Luc


Eror 500 on your posted link, Lic.
 




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