Idea for portable AOA device

[jaylw314]

I'm just randomly thinking.  Would it be feasible to make a portable AOA device by attaching a sensor to your side window?  If you take a small windvane with a metal base, you could attach it to your side window with a rare-earth magnet on the inside (both protected by rubber, of course).  The windvane has a electronic position sensor and bluetooth transmitter, with the receiver being a display that you would velcro to the top of your glareshield.

Since it is not permanently attached to the plane, it requires no installation.  It might need calibration, or you could have the receiver use the position during the ground roll as your zero degree calibration automatically.

Heck, if you wanted to go really low tech, you could just have a mirror on the glareshield pointing at the windvane on the side window.

Anyway, just my brain droppings for today...

[jetdriven]

As long as the airplane is producing thrust the AOA vane inside the prop arc is useless. If shows relative wind which is always going to be changing. Basically it shows lower AOA as thrust goes up. So it’s accurate except the 90% of the time it’s not. 

Edited February 2, 2018 by jetdriven

[carusoam]

A lot of ideas start out this way...

Keep working on it, Jay.

The challenge of picking the AOAi... As a project...

If you get the install or design wrong, it can lead to a stall.

There is a thread around here for the CYA-100 an AOAi system, while it was being developed...

Low cost, works, and pretty helpful...

A few have been installed by MSers.

Best regards,

-a-

[Yetti]

Or just learn to fly as apposed to trying to program the plane. :-)

I would think a AoA would be pretty easy to build.

I just built a home alarm system using a PIR and Raspberry PI Zero with camera.   It is going to flash lights via the Wemo and play audio clips via the HDMI.

Next up is a ground sensor like they have on big planes that calls out "150 feet", 100 feet, 50 feet, 25 feet, just like the big planes. Going to velcro it inside the front wheel weel

 

 

[Yetti]

Ok so what I learned from the internet is that AoA use a pitot tube and an aerodynamic model to keep you on the POH numbers.

So basically it is a real time visualization of the PoH statement "don't go below 90 mph in the pattern without flaps deployed"

 

[DXB]

It's striking to me that Aspen offers a perfectly good AoA indicator based on integration of AHRS and airspeed data, with no additional external sensor.  What has kept me from adopting so far is the itty bitty display for it on my pfd.  An external display for the glare shield using the same data (via the Aspen or otherwise) would make me buy in an instant.  I am not fond of the idea of another install out on my wing when the needed data is already in the cockpit.  

[carusoam]

The AOA can use a few different methods of measuring... pressure differential and vanes...

The nice part is...

When working and calibrated properly...

it eliminates the need for memorizing stall speed charts, including weight variations, all bank angles, and flap positions...

or limiting your flight characteristics because you didn't do all the math or are not confident in your memory...

Even my stall charts don't include effects of nose down attitudes...

Staying above 90 and limiting bank angle to less than 30°are pretty helpful guidelines, but can lead to higher speeds on final approach and overshoots during the turn to final....

PP thoughts on AOAi, not an instrument guy or CFI.

Best regards,

-a-

 

 

 

[jaylw314]

 

12 hours ago, jetdriven said:

As long as the airplane is producing thrust the AOA vane inside the prop arc is useless. If shows relative wind which is always going to be changing. Basically it shows lower AOA as thrust goes up. So it’s accurate except the 90% of the time it’s not. 

Good point, I hadn't thought about that.  I guess my thinking is a way of installing it that isn't a permanent installation.  How about on the wingtips?  If you had a vane on each wingtip, and mixed the two positions, that would give you some kind of average AOA.  If both wingtips had a high AOA and differed by too much angle, the unit could give a second spin warning alert...

[jaylw314]

1 hour ago, Yetti said:

Or just learn to fly as apposed to trying to program the plane. :-)

I would think a AoA would be pretty easy to build.

I just built a home alarm system using a PIR and Raspberry PI Zero with camera.   It is going to flash lights via the Wemo and play audio clips via the HDMI.

Next up is a ground sensor like they have on big planes that calls out "150 feet", 100 feet, 50 feet, 25 feet, just like the big planes. Going to velcro it inside the front wheel weel

 

 

And yes, I was thinking about this in terms of a Raspberry Pi project, but I'm putting it out there because it might go like my RV-10 project--halfway through, 20 years to go...

[Yetti]

So if the AoA is using a model and a pitot tube, how does it know if the flaps are up or down?

 

[Yetti]

Yep I could totally do this along with a 6 pack based on the Raspberry PI sense hat and a ubloc 7 glasnos GPS.   Not sure what the portable requirement is.   If you worried about regulations attach the pitot tube like a camera mount to a access panel or the tie down ring.   I like dual pitot tubes since that would immediately let you know airflow across each wing.

https://www.amazon.com/FREESCALE-SEMICONDUCTOR-MPX10DP-PRESSURE-SENSOR/dp/B00MMY5SPO/ref=pd_sbs_328_2?_encoding=UTF8&pd_rd_i=B00MMY5SPO&pd_rd_r=Y59W46B1FJQ895NS8M4V&pd_rd_w=YVbbK&pd_rd_wg=btqCf&psc=1&refRID=Y59W46B1FJQ895NS8M4V

[carusoam]

Yetti,

1) Technically, It is possible to include the flap position sensor that some Mooneys have...

2) With the method that the Aspen uses, they have two pointers on a scale that the pilot needs to be aware of, and not use the wrong pointer...  they use triangles as the pointers.  One sort of looks more like flaps down than flaps up...

Best regards,

-a-

[jaylw314]

1 hour ago, Yetti said:

Yep I could totally do this along with a 6 pack based on the Raspberry PI sense hat and a ubloc 7 glasnos GPS.   Not sure what the portable requirement is.   If you worried about regulations attach the pitot tube like a camera mount to a access panel or the tie down ring.   I like dual pitot tubes since that would immediately let you know airflow across each wing.

https://www.amazon.com/FREESCALE-SEMICONDUCTOR-MPX10DP-PRESSURE-SENSOR/dp/B00MMY5SPO/ref=pd_sbs_328_2?_encoding=UTF8&pd_rd_i=B00MMY5SPO&pd_rd_r=Y59W46B1FJQ895NS8M4V&pd_rd_w=YVbbK&pd_rd_wg=btqCf&psc=1&refRID=Y59W46B1FJQ895NS8M4V

The tiedown ring idea is an interesting one, I imagine that might not see negative AOA as well (although that is less important anyway).  The access panel idea is less convenient, since it will still require an A&P to sign off unless you keep an extra panel to reinstall if an inspector comes along!

[HRM]

9 hours ago, Yetti said:

So basically it is a real time visualization of the PoH statement "don't go below 90 mph in the pattern without flaps deployed"

Say what? Jeez. I'm glad The Mistress doesn't know that. She hates flaps, disturbs her lines...

[carusoam]

 

@aviatoreb might want to share this thread with a young buck that worked on a similar project a while ago...

Best regards,

-a-

[Yetti]

9 hours ago, HRM said:

Say what? Jeez. I'm glad The Mistress doesn't know that. She hates flaps, disturbs her lines...

Did not say full flaps....    I usually go half flaps for landing. #mooneyfast  #dontturnthisintoalandingdiscussion

Apparently inspection covers are only $11.00

Pitch and yaw come from the sensehat

seems like a integrated pitot static tube on each wing is the way to go.  Less mounting and running of tubes.   https://www.eaa.org/en/eaa/aviation-communities-and-interests/homebuilt-aircraft-and-homebuilt-aircraft-kits/resources/building-articles/instruments-and-avionics/installing-a-pitot-static-system

If we are going for one on each wing, the better AoA would have a keep from slipping/skiding   So the display would be like an OLS from a carrier.  

 

[Yetti]

And it looks like I could run a audio output cable to the headset input jack(or audio panel) and have it tell you (Slip slip slip, skid skid skid, or stall stall stall)  or we could keep the carrier theme (on glideslope)

[M016576]

4 hours ago, Yetti said:

Did not say full flaps....    I usually go half flaps for landing. #mooneyfast  #dontturnthisintoalandingdiscussion

Apparently inspection covers are only $11.00

Pitch and yaw come from the sensehat

seems like a integrated pitot static tube on each wing is the way to go.  Less mounting and running of tubes.   https://www.eaa.org/en/eaa/aviation-communities-and-interests/homebuilt-aircraft-and-homebuilt-aircraft-kits/resources/building-articles/instruments-and-avionics/installing-a-pitot-static-system

If we are going for one on each wing, the better AoA would have a keep from slipping/skiding   So the display would be like an OLS from a carrier.  

 

Oh the good old days!  You just brought a single tear to my eye.....

 

CATC: “301TV, three quarters of a mile, on and on, call the ball”

me: “301TV, Mooney, Ball, .5, auto.”

LSO: ”Roger ball, auto!”

 

technically that picture is an IFOLS, the older OLS only had 5 cells on it... and was much harder to fly (for me, anyway...some guys made it look easy!)

Edited February 3, 2018 by M016576

[aviatoreb]

17 hours ago, carusoam said:

 

@aviatoreb might want to share this thread with a young buck that worked on a similar project a while ago...

Best regards,

-a-

Young buck is really becoming an expert in fluid dynamics and turbulence!  Bollt 2.0.  The new improved version!

[aviatoreb]

3 hours ago, M016576 said:

Oh the good old days!  You just brought a single tear to my eye.....

 

CATC: “301TV, three quarters of a mile, on and on, call the ball”

me: “301TV, Mooney, Ball, .5, auto.”

LSO: ”Roger ball, auto!”

 

technically that picture is an IFOLS, the older OLS only had 5 cells on it... and was much harder to fly (for me, anyway...some guys made it look easy!)

So you are landing your missile on top of your house?!

[marky_24]

On 2/2/2018 at 11:44 AM, jaylw314 said:

 

Good point, I hadn't thought about that.  I guess my thinking is a way of installing it that isn't a permanent installation.  How about on the wingtips?  If you had a vane on each wingtip, and mixed the two positions, that would give you some kind of average AOA.  If both wingtips had a high AOA and differed by too much angle, the unit could give a second spin warning alert...

I wouldn't think the wing tips would work because of wing tip Vortices.

[HRM]

13 hours ago, Yetti said:

...seems like a integrated pitot static tube on each wing is the way to go.

Piper's had a pitot-static arrangement. Some RV guys have put a small, bent tube in the static port (hole at the bottom) and turned the thing into an AOA. Clever.

[Yetti]

So I get AoA for proper landing speeds that would prevent over runs by coming in hot.   Can someone tell me how AoA are supposed to help prevent Base stall spins?

 

 

[aviatoreb]

6 minutes ago, Yetti said:

So I get AoA for proper landing speeds that would prevent over runs by coming in hot.   Can someone tell me how AoA are supposed to help prevent Base stall spins?

 

 

During that statistically base to final turn, getting too slow/yanking too much g’s on the yoke causes low altitude (often uncoordinated) stalls.  With an aoa you can see exactly how close you are to stall at all times, including during base to final turn.  Of course you need to train the habit of noticing.

[Yetti]

1 minute ago, aviatoreb said:

During that statistically base to final turn, getting too slow/yanking too much g’s on the yoke causes low altitude (often uncoordinated) stalls.  With an aoa you can see exactly how close you are to stall at all times, including during base to final turn.  Of course you need to train the habit of noticing.

so it's doing nothing to tell you that you are slipping or skidding in the base to final?   Seems that if we are adding more instruments we should have ones that are telling us that we are not flying properly