AX-O

AX-O

Well Known Member
I purchased a Dynon pitot tube but did not install Dynon avionics in my Fastback. I don?t want to buy a Dynon EFIS just for the AOA option. Is there a non-EFIS type product out there that can take the info from a Dynon pitot tube and display the info for AOA? I have searched but everything i have found requires a dedicated "full" system. I am not interested in that. Thanks for any help.
 
Take a look at the Advanced Flight Sport AOA. It uses a simple glare shield mount display that works very well. It does not connect to a pitot. but uses two #60 holes in the leading edge of the wing. About $600 total IIRC.

I started with the AF Pro AOA as part of their AF3400 efis, but it is mounted in the center of my -10 panel. Just far enough out of my line of sight to not be very useful on final. I really liked the glare shield mount on the factory -10 when I took transition training, so I recently added it.

Doesn't every RV need 2 AOAs?;)
 
I want to use the current capability provided by my Dynon pitot tube (AOA) but I don't want to buy another EFIS just for a display.
 
AX-O said:
I want to use the current capability provided by my Dynon pitot tube (AOA) but I don't want to buy another EFIS just for a display.
Click to expand...

I think I can answer your question.

I use a LRI probe to drive not only the LRI indicator but also the Dynon angle of attack indicator in the D10-A.

I believe this would infer that the Dynon probe should drive the LRI indicator properly. Here is an info page on the LRI system that has been flying in my RV-6 for over a dozen years:

http://thervjournal.com/liftreserve.htm
 
AX-O said:
I want to use the current capability provided by my Dynon pitot tube (AOA) but I don't want to buy another EFIS just for a display.
Click to expand...

I'm using the Dynon Pitot probe with the Advanced Flight PRO AOA system. Gives me a nice glare shield indication of AOA and does not require any other EFIS systems to function.

Untitled by akarmy, on Flickr
 
Been looking into DIY AOA recently myself...

It might be possible to get a simple differential pressure gauge indicator and get it to work with Dynon's AOA Pitot yourself by calibrating a home made face-plate for the indicator.

Found this link: http://www.ch601.org/resources/aoa/aoa.htm
on this thread: http://www.vansairforce.com/community/showthread.php?t=36775
which has part numbers for round & rectangular differential pressure indicators. They seem to be readily available & fairly inexpensive:
http://www.amazon.com/Dwyer-Minihelic-Series-Differential-Pressure/dp/B009PC6O7M

The trick would be getting one to match the range in differential pressure for the Dynon pitot. 0-500pa seems to be the range for the LRI type probe. Maybe Dynon has these numbers for their probe and could share them?

Wondering if someone on the forums has tried this?
 
akarmy said:
I'm using the Dynon Pitot probe with the Advanced Flight PRO AOA system. Gives me a nice glare shield indication of AOA and does not require any other EFIS systems to function.
Click to expand...

Thats what i was trying to fugure out. How does it work (accurate)? How did you calibrate it? What did you buy? How did you install the Advanced Flight PRO AOA system, per their manuals? Details!!!!!!!:D
 
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AX-O said:
Thats what i was trying to fugure out. How does it work (accurate)? How did you calibrate it? What did you buy? How did you install the Advanced Flight PRO AOA system, per their manuals? Details!!!!!!!:D
Click to expand...

The newest iteration of the AOA pro supports connection to the Dynon AOA enabled pitot. I think it's the AOA pro V3 but you can call to verify. You can't get an old one off someone as it needs to have the newer firmware.

You just feed it AOA and Pitot lines into the little brain box and it's good to go. The out of the box calibration did not work for my RV-8 so I simply followed the instructions on how to calibrate the system. You do some zero g in both landing and clean configs and set the glide speed vs AOA you desire. I had to do it a couple of times to get it slowed down where I wanted it. Once it's calibrated it works great. I have tested it in all sorts of situations during phase 1 and it was always spot on.

If you line up the donut you get a nice 3 point landing with just enough energy. If you setup two bars of green (best glide and best climb also) you have the right energy for a wheel landing. When you are heavy and slow it talks to you for sure. and at the top of the loop you here a little angle angle push sometimes as you get slow.

I bought the complete AOA pro kit from Advanced Flight Systems which included the Dynon Pitot (unheated) probe as well. I used a Safe-Air mast to install the Pitot in. If you already have the Dynon probe just give Rob a call and they can sell you just what you need to get it all hooked up.

Happy to answer other questions.
 
Great info! Glad you asked this Ax!

Hypothetical Qs, and I will call Rob too?

I have a Dynon AOA pitot, plumbed to a D100. AOA displays on the D100 fine, and my AP-74 gives tone or voice warnings. I have an aftermarket LED repeater (Vern's) on the glareshield.

Working a couple ideas/projects.

Q1. If I purchase the AOA Pro to replace the LED repeater and gain the added features of the AOA Pro, will it augment or conflict with the current AP-74 aural warnings, or can that legacy feature be switched off? Is this a straight forward mod to a legacy Dynon system?

Q2. Is there a low-profile pitot option that can provide both of the required ports?

Thanks much!
Cheers,
Bob
 
Bob,

If you are not wedded to using the Dynon pitot for your AOA ports, the AF Pro and Sport AOA normally uses two #60 holes in the leading edge for ports. That probably qualifies as no profile (better than low profile). You could still use the Dynon pitot, or whatever, for AS.
The aural warnings on the AF AOA can be inactivated. I don't know about the Dynon, but I don't think you would want both AOAs talking to you.
 
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Thanks Jim,

LE holes may be a possibility. I've been contemplating a low-drag pitot that could do both AS and AOA?kind of a two-fer, since I have the pitot and AOA lines run already.

Anyone engineer such a thang? Mel, I remember you were asking about the angle between the ports on the Dynon AOA pitot (I think we measured it at 62 deg). Did you ever make a DIY AOA pitot?

Cheers,
Bob
 
Some Inof on AOA Implementation

This is a link to a NACA paper that discusses AOA measurements in some depth.

http://naca.central.cranfield.ac.uk/reports/1958/naca-tn-4351.pdf

Basically you are using a probe to make a differential pressure measurement between the two ports. The configuration of the probe Dynon or others should not make too much difference. We have made up several simple instrumentation packages using setups like the Dynon installation and other probes configured as shown in the paper. We just connect a relatively low cost MEMS differential pressure sensor like the one below to a bargraph display or voltmeter:

http://www.digikey.com/product-detail/en/MPXV7007DP/MPXV7007DP-ND/1168438

This link may be of use as well. You may want to build up the electronics and connect them to the ports on your Dynon probe and give it a try.

http://www.sonex604.com/aoa.html

If you need additional information just PM me and perhaps I can help. I am located in SoCa and get up to Ridgecrest from time to time.

larosts
 
You can add an AOA sensor for about $12 in parts. Read this thread and start at post 14. Keep reading and you will find that the tire inflation needle can be replaced with a simple static-system type of rivet. That is really low profile!

http://www.vansairforce.com/community/showthread.php?t=34040&page=2

This AOA mod works great for us RV12s with Dynon systems. The 1/8 inch tubing works fine. We RV12s have a conventional leading edge stall warning switch with an access door so working through that door made the retrofit easy. Might be tougher for other models.

Remember - an AOA sensor is essentially just a pitot sensor pointed 30 degrees down as compared to the pitot.
 
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Bill and Curtis,

Both neat ideas! I can see putting a Delta Pop fairing around Mel's design too. Hmmmm? ;)

Thanks guys!

Cheers,
Bob
 
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