Adjusting AoA?

[boat45]

I've calibrated my AoA values in SkyView, and in my LSA it starts beeping at approx 50kts and is full beep around 45kts. That's with the audio tone set to come on at 50%, which is the lowest value that can be configured. I can make it beep when testing stalls at altitude.

..but it never seems to go off when I'm landing, and it seems like it should. The "inhibit" speed is set sufficiently low. I finally pulled the data and plotted it. I normalized the landings by putting the zero point on the highest AoA value.

You can see that in 8 landings the top AoA value is 45%. The speed (TAS) is above 45kts when the peak is reached.

I'd assume a good point for AoA beeping would be just above a standard approach envelope, so I should hear beeps on almost every landing, and I should definitely hear it when I get a landing wrong (say, stalling it a few feet above the runway resulting in a "drop" landing).

What should I do to get the AoA warnings where I want them? If I could adjust the warning threshold to about 40% it seems like it would be acceptable, but the configuration only allows a value as low as 50%. Alternately, should I perform the calibration stalls in another way? Recover before a full stall, perhaps?

 

[Dynon]

You've got it. Your stall demonstrations are sufficiently deep such that your landing isn't hitting that high of an AOA. Your proposed solution will work: demonstrate a less aggressive AOA during the "stall" portion of the calibration.

 

[swatson999]

Doesn't this mean that you're not landing at the stall speed, but rather, "flying it onto the runway"? Granted I think we all do this at least some of the time, but I was taught to try to hold it off until it actually stalls right at touchdown.

 

[Jim8JD]

I've calibrated my AoA values in SkyView, and in my LSA it starts beeping at approx 50kts and is full beep around 45kts. That's with the audio tone set to come on at 50%, which is the lowest value that can be configured. I can make it beep when testing stalls at altitude.

..but it never seems to go off when I'm landing, and it seems like it should. The "inhibit" speed is set sufficiently low. I finally pulled the data and plotted it. I normalized the landings by putting the zero point on the highest AoA value.

You can see that in 8 landings the top AoA value is 45%. The speed (TAS) is above 45kts when the peak is reached.

I'd assume a good point for AoA beeping would be just above a standard approach envelope, so I should hear beeps on almost every landing, and I should definitely hear it when I get a landing wrong (say, stalling it a few feet above the runway resulting in a "drop" landing).

What should I do to get the AoA warnings where I want them? If I could adjust the warning threshold to about 40% it seems like it would be acceptable, but the configuration only allows a value as low as 50%. Alternately, should I perform the calibration stalls in another way? Recover before a full stall, perhaps?

I've been working on the same problem in my RV6A with Skyview Touch. I did a low pwr stall recently and didn't hear the tones start until a couple knots before the stall. I pulled the logs and uploaded to Savvy and looked at the AOA, IAS and PALT at stall and found the AOA was 52% at stall with IAS 49.5 kts. I then looked at landing and found AOA was 39% with IAS 52.3 kts at touchdown.... not even close to hearing an AOA tone. I don't understand why the lower limit for AOA % is limited to 50% ... I would like to see that lower limit removed or adjusted down to 30% limit so we can set it where we want to get audio alerts to work during landings, which is the time they are most useful to me. In my case with AOA at 50% I didn't start hearing the tone until a few knots and a couple seconds before the solid tone and actual stall... I would like more advanced warning of a stall than that, especially during landings when approaching stall speeds. I feel this would be a better solution than doing less aggressive stalls to fool the system.

 

[Solana]

I've calibrated my AoA values in SkyView, and in my LSA it starts beeping at approx 50kts and is full beep around 45kts. That's with the audio tone set to come on at 50%, which is the lowest value that can be configured. I can make it beep when testing stalls at altitude.

..but it never seems to go off when I'm landing, and it seems like it should. The "inhibit" speed is set sufficiently low. I finally pulled the data and plotted it. I normalized the landings by putting the zero point on the highest AoA value.

You can see that in 8 landings the top AoA value is 45%. The speed (TAS) is above 45kts when the peak is reached.

I'd assume a good point for AoA beeping would be just above a standard approach envelope, so I should hear beeps on almost every landing, and I should definitely hear it when I get a landing wrong (say, stalling it a few feet above the runway resulting in a "drop" landing).

What should I do to get the AoA warnings where I want them? If I could adjust the warning threshold to about 40% it seems like it would be acceptable, but the configuration only allows a value as low as 50%. Alternately, should I perform the calibration stalls in another way? Recover before a full stall, perhaps?

You can download the Dynon settings file and adjust the Offset for each of the flap settings you have calibrated the AOA for. I had it calibrated for -3, 0, 15, and 30 degrees.

Changing the offset actually changes the behavior of the scale, so the speed at which the beep starts is changed because the speed at which you reach the yellow green border is adjusted. I love that, that is absolutely perfect.

So now, I have the yellow green border around 1.25 times stall at each of my four flap settings. To accomplish this I’ve moved the offset (which used to be around -0.1 to -0.19) to -0.3 to -0.35 give or take a little.

Play with it and you can have it do exactly what you want.

Rick

 

[Jim8JD]

You've got it. Your stall demonstrations are sufficiently deep such that your landing isn't hitting that high of an AOA. Your proposed solution will work: demonstrate a less aggressive AOA during the "stall" portion of the calibration.

Is there a technical reason for the AOA audio alert lower limit being set to 50%? I require more power be added to get AOA above 50% in my RV-6A, which is not representative of landing power settings or speeds. If the lower limit were eliminated, it would allow pilots to look at their downloaded logs to see what AOA% and IAS they are landing at and set the lower limit in the audio alert accordingly to get a slow beep as they are touching down, like my old Cessna's did. That method would allow the AOA Audio Alert to be tailored to different plane types. My logs show stall landings with AOA at 41% and IAS 48.5 kts, not close to hearing a slow tone, while at VS0 full flap stall speed. Please advise... I must be missing something. Thanks, Jim

 

[Solana]

Is there a technical reason for the AOA audio alert lower limit being set to 50%? I require more power be added to get AOA above 50% in my RV-6A, which is not representative of landing power settings or speeds. If the lower limit were eliminated, it would allow pilots to look at their downloaded logs to see what AOA% and IAS they are landing at and set the lower limit in the audio alert accordingly to get a slow beep as they are touching down, like my old Cessna's did. That method would allow the AOA Audio Alert to be tailored to different plane types. My logs show stall landings with AOA at 41% and IAS 48.5 kts, not close to hearing a slow tone, while at VS0 full flap stall speed. Please advise... I must be missing something. Thanks, Jim

Setting the alert at 50% will set the AOA to start beeping at the green/yellow border. If you move it higher then you move the beep into the yellow, towards the red.
The speed at the green/yellow border is changed by the Offset. Right now you are at about 10% above stall. My Offset change puts me around 26%. It’s an earlier warning, and you might hear the alert in the pattern if you are slow enough, eg doing a short field approach.

 

[Jim8JD]

Setting the alert at 50% will set the AOA to start beeping at the green/yellow border. If you move it higher then you move the beep into the yellow, towards the red.
The speed at the green/yellow border is changed by the Offset. Right now you are at about 10% above stall. My Offset change puts me around 26%. It’s an earlier warning, and you might hear the alert in the pattern if you are slow enough, eg doing a short field approach.

Thanks for that info I'll give it a try.

 

[Jim8JD]

Setting the alert at 50% will set the AOA to start beeping at the green/yellow border. If you move it higher then you move the beep into the yellow, towards the red.
The speed at the green/yellow border is changed by the Offset. Right now you are at about 10% above stall. My Offset change puts me around 26%. It’s an earlier warning, and you might hear the alert in the pattern if you are slow enough, eg doing a short field approach.

I have not been able to find any info in Dynon Skyview docs about where to find and change the offsets you are referring to... could you please help point me to where to look? Thanks much for your help.

 

[boat45]

You can download the Dynon settings file and adjust the Offset for each of the flap settings you have calibrated the AOA for. I had it calibrated for -3, 0, 15, and 30 degrees.

Changing the offset actually changes the behavior of the scale, so the speed at which the beep starts is changed because the speed at which you reach the yellow green border is adjusted. I love that, that is absolutely perfect.

So now, I have the yellow green border around 1.25 times stall at each of my four flap settings. To accomplish this I’ve moved the offset (which used to be around -0.1 to -0.19) to -0.3 to -0.35 give or take a little.

Play with it and you can have it do exactly what you want.

Rick

Wow, really interesting here. I grabbed the config file and found the following.

First, I have two AHRSes, so there were two offsets.

    aoa_offset=0.117499
    aoa_offset=0.137263

Here's an example from one of them with my flap settings- interesting that they are empty/default.

  has_pitot_adjust=1
  has_aoa_adjust=1
  aoa_cal_uses_pitotadj=1
  aoa_valid=1
  aoa_gain=0.571695
  aoa_offset=0.137263
  flap_aoa_cal={
    valid=0
    gain=1
    offset=0
    flap_pos=0
    }
  flap_aoa_cal={
    valid=0
    gain=1
    offset=0
    flap_pos=0
    }

I don't have any flap_aoa_cal sections with values other than this. You're in a Flight Design? How does the Dynon know which flap setting?

In any case, it sounds like I should move that offset from 0.11 to 0.3 and see what happens. Or are yours truly negative offsets?

 

[Jim8JD]

I didn't realize that changing offsets requires editing and changing the offsets in the downloaded configuration file of the Skyview. I'll download the settings again and update the offsets and go from there. Thanks much!

 

[Rhino]

...You're in a Flight Design? ...

Last I knew, Solana had an RV-10.

 

[boat45]

Last I knew, Solana had an RV-10.

Thanks. Was trying to guess based on the reflex flaps. Does the RV10 have a flap sensor connected to the Dynon system?

 

[Rhino]

Beats me. Not familiar with the RV-10.

 

[Solana]

Wow, really interesting here. I grabbed the config file and found the following.

First, I have two AHRSes, so there were two offsets.

    aoa_offset=0.117499
    aoa_offset=0.137263

Here's an example from one of them with my flap settings- interesting that they are empty/default.

  has_pitot_adjust=1
  has_aoa_adjust=1
  aoa_cal_uses_pitotadj=1
  aoa_valid=1
  aoa_gain=0.571695
  aoa_offset=0.137263
  flap_aoa_cal={
    valid=0
    gain=1
    offset=0
    flap_pos=0
    }
  flap_aoa_cal={
    valid=0
    gain=1
    offset=0
    flap_pos=0
    }

I don't have any flap_aoa_cal sections with values other than this. You're in a Flight Design? How does the Dynon know which flap setting?

In any case, it sounds like I should move that offset from 0.11 to 0.3 and see what happens. Or are yours truly negative offsets?

In my file, the flap position shows the flap setting I had set in the calibration process, so I have four showing (-3, 0, 15, and 30 degrees). The other two positions that are available show a flap position of 0. The ones that are inactive have an offest of 0 in my files.
My offsets are all negative numbers!!

 

[Solana]

I have not been able to find any info in Dynon Skyview docs about where to find and change the offsets you are referring to... could you please help point me to where to look? Thanks much for your help.

download the user_config.dfg file and edit it with a text editor, then upload it back to your skyview. You'll find the AOA settings after scrolling down a bunch under the ahrs module section.

 

[Solana]

Last I knew, Solana had an RV-10.

yup. it's an RV10 with Skyview HDX.

 

[Solana]

Thanks. Was trying to guess based on the reflex flaps. Does the RV10 have a flap sensor connected to the Dynon system?

it's not specific to the RV10, but Dynon does have a flap sensor option. With that you can set up for several flap settings (a new feature in the recent software). Otherwise, you have to settle for one setting that is used no matter the flap setting.

 

[Solana]

In my file, the flap position shows the flap setting I had set in the calibration process, so I have four showing (-3, 0, 15, and 30 degrees). The other two positions that are available show a flap position of 0. The ones that are inactive have an offest of 0 in my files.
My offsets are all negative numbers!!

I also have two AHRS and put the values in for both.

 

[Jim8JD]

download the user_config.dfg file and edit it with a text editor, then upload it back to your skyview. You'll find the AOA settings after scrolling down a bunch under the ahrs module section.

I found it by doing a search in the editor for aoa_offset and the 2nd hit was it. I changed it from -0.06xxx to -0.15 for starters so I'll see what difference that made next time I fly and go from there. Thanks!