What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

ON SPEED Angle of Attack Video

I wonder if the folks using AOA in their airplanes have instruments that read-out degrees AOA. Units with a couple of colored LEDs are in my opinion no more useful that a traditional stall warning device. The units that actually display degrees AOA with precision are VERY useful. Gusty conditions ALWAYS require an extra margin of safety for both airspeed and AOA. Where AOA REALLY shines is scenarios such as this: Hot day, full fuel, short field, grass runway, trees at the end. You really want to nail Vx and/or Vy and nail them quickly. The problem is your airspeed indicator has too much hysteresis (sluggish) and you don't wan't those trees in your windscreen when you finally settle on an airspeed. With AOA you rotate and go immediately to the AOA (in degrees) that corresponds to Vx and forget your airspeed indicator - it will catch-up later. So I respectfully disagree that AOA is a fad, but you need a good, precise instrument.
I don't see why a numerical readout is necessary. So long as you can repeatably hit your target AOA, it doesn't matter whether there's a numerical readout, a tick mark on a scale, a certain number of colored bars, or a threshold of ticks or beeps on an audio readout.
 
Whatever works for you

I don't see why a numerical readout is necessary. So long as you can repeatably hit your target AOA, it doesn't matter whether there's a numerical readout, a tick mark on a scale, a certain number of colored bars, or a threshold of ticks or beeps on an audio readout.

but in my experience ticks, bars and beeps don't provide the resolution (1 degree is necessary in my opinion) needed to really take advantage of AOA. If you can tell me when you're at 8 degs AOA (Vx in a lot of airplanes), with a tick, bar or beep then you got it!

Unfortunately most people only think of AOA utility in terms of stall spin avoidance, but that's just a fraction of it's utility, and if all you want is a beep for impending stalls, then you may already have a stall warning device.
 
Spot on, gents. We've found a plus or minus one degree ish band to work well for ONSPEED. We've gotten good performance at G onset rates of up to 2 per second with yaw angles less than 6 degrees with our current tone generator.

The quality of EFIS AOA data actually varies as a function of the algorithm and calibration--both of which can be problematic...we've learned quite a bit during beta test watching folks in the filed calibrate a commercially available AOA. Turns out some commercially available AOA systems only provide progressive stall warning (and do a great job of that, by the way), but don't necessarily capture ONSPEED or L/Dmax conditions. These are two critical AOA's that help make energy management easy for a ham-fisted pilot like me.

We are excited to start experimenting with a new homebuilt system that measures AOA to within 1/4 to 1/2 degree resolution and is easier to accurately calibrate. We'll post results here as we learn more.

Cheers,

Vac
 
Thank you for your work in this area. This device has the potential to vastly improve the safety record for GA. I hope you will consider applying for the 2017 EAA Founder?s Innovation Prize. You would be a shoe-in!

Congrats on winning the Founder's Innovation Prize Vac!

It was great to hear your presentation, and to meet you and your colleagues on this project up at OSH last week. I wish I could get one of these for my AFS system, so I'll be waiting for the standalone pressure sensor interface your buddy is working on.
 
Update and new video

Hi Folks!

I posted a new, long unedited video of a recent software validation flight here: https://youtu.be/-iudL-gAL5E . We’ve added an additional oblique camera to our test RV-4, which provides the view over the left wing. This view can be helpful for pattern operations. The relative sound levels, including engine noise and radio give some idea of the general volume adjustment for the AOA tone.

We are currently working on reducing the perceived “harshness” of the simple digital tone by using more advanced digital to analog capability. We hadn’t done this yet, since our original intent was to simply demonstrate the utility of this type of aural logic to assist with energy management. The basic digital tone was sufficient for that purpose. Unfortunately, this simple digital tone has not translated well to video, especially if other ambient sounds are edited out and tone volume is increased to ensure proper recording; so, we think that’s an important fix to overcome what we’ve dubbed “green eggs and ham syndrome.”

The notes for this flight are here, and include time hacks for each pattern and maneuver: https://drive.google.com/file/d/1QKHbcr26q_ldzI1CBmSO1aJc0zE22WwG/view?usp=sharing . Detailed descriptions of the handling techniques in the video and how ONSPEED maneuvering is used in an operational environment can be found in the transition training manual in the sticky at the top of this page or in this video: https://youtu.be/-kbA6NxMpmQ

Our most current version of the software is 1.5.2. It is mature for DY-series EFIS and in beta test for SkyView-series EFIS. We’ve also updated the circuit diagram for the tone generator hardware. Both are available here: https://github.com/dinglewanker/aoa-tone-efis-serial . We’ve finalized the pulse rates to improve resolution between ONSPEED and “slightly fast” and fixed a software glitch with the 400Hz tone. A demonstration of the new pulse rates in our high tech ;) simulator is here: https://youtu.be/FEhGAfbQIgA .

Perhaps the biggest thing we’ve learned in beta test is that each Dynon AOA calibration is unique. With our first-generation system, this requires software settings for each airplane to accommodate differences in calibration. We’ve also learned that some folks have difficulty properly calibrating angle of attack systems in the field. At the conclusion of this test, we’ll publish a beta test report on our new website (flyonspeed.org). Our new site is currently under construction, but eventually we’ll consolidate information and what we’ve learned there as well as continuing to post here in the safety section of VAF.

As a result of lessons learned, we are pressing ahead with a new design for a tone generator that has indigenous pressure sensors and will (we think!) require minimal calibration. The box computes angle of attack from differential pitot pressures and has a more capable processor equipped with onboard data recording. We are calling this project “Gen 2.” It’s based on work started by Dave Rogers, a professor of aerodynamics at the Naval Academy (see DOT/FAA report TC-18/7 for details: http://www.tc.faa.gov/its/worldpac/techrpt/tc18-7.pdf ). Dave has graciously provided us with some calibrated test equipment and support (which is especially helpful for a math-challenged, unfrozen caveman former fighter pilot :) ). For developmental test, we are installing this new box in an Aeronca Champ, the RV-4 and an RV-10 to capture a representative range of EAB types. We plan to test with Dynon, Garmin, Alpha Systems and simple dual bent tube sensors. Here are a few photos of the new prototypes:

https://drive.google.com/file/d/1oWLK6vM6jBlu_fBn0mzUk1iJ-9049bWK/view?usp=sharing

https://drive.google.com/file/d/1ykR4mEfh8j2JjTJd5LmJuxmv90nLVvcQ/view?usp=sharing

https://drive.google.com/file/d/1glzm2jIde44V7pbPkMIiT_sxu82SHfbG/view?usp=sharing


For folks that aren’t interested in building their own system, the aural logic is currently available as a pilot-programable mode in MGL EFIS. It’s also available with Alpha Systems stand-alone AOA systems and we are currently working with the engineers at WingBug (https://www.wingbug.com) to have the logic available with that sensor as well.

Cheers,

Vac
 
Last edited:
standalone box

Hi Mike, thanks for the update. The standalone box looks great - I assume it will take the two pressures on an "AOA" pitot tube like the Garmin GAP-26, power, and output the ONSPEED tone?

Any discussions with the boys at GRT? :D
 
Hi Mickey,

Yes. It will work (we think—I’d advise you to wait for the test report ;) ) with the Garmin sensor or any sensor that has a “P forward” and “P 45” pitot source, even simple bent tubing. So far our only flying system uses the Dynon sensor. Great question, BTW.

A good friend is finishing up his Panther and has a GRT EFIS. We looked at his documentation and may be able to use the basic Dynon serial output processing logic with that system. We are going to install a prototype in that airplane after initial Phase 1 tasks are complete and experiment. It will depend on the algorithm GRT uses to compute AOA.

Some commercial AOA systems don’t accurately measure absolute AOA accurately except near stall (i.e., they are just very good progressive stall warning systems), and may not accurately capture ONSPEED or L/Dmax. The Gen 2 box does and as a stand-alone tone generator can be installed in any airplane with a differential pitot sensor. That’s why one of our test airplanes is a round-dial Champ with a prehistoric simple bent tubes for pitot and static sources. We are fitting a third “bent” pitot tube for the 45-degree pitot source.

Cheers,

Vac
 
Last edited:
Gen 2 Audio

The new system includes code that allows the user to manipulate the tone waveform and volume for different parts of the tone logic, which is simply a fancy way of saying the tone can be made to be much more pleasant to listen to: https://youtu.be/WTHszmvjI24

Cheers,

Vac
 
Yes

We are, but need to finish up flight test first. We also plan to have all of the information available on our new website flyonspeed.org when we get that up and running!
 
Hi Vac,
Great work you and the team are doing?
Will the new digital to analog sound be available to the 1st Gen aoa?
And how long do you think it will be before 2nd Gen is out?
Thanks
Dale
 
Nice work, Vac. A very impressive project. Glad you included the segment demonstrating the sound in a 'normal' cockpit.
 
This is the best informative video I've ever seen. Posting mainly to have a placard to come back to for reading everything in here.

What AoA system is this?
 
Replies

Dale,

Yes, we are looking at adding "analog" tone to the Gen 1 code. We are working hard on Gen 2 now, have some more flight testing to do, and since this is a hobby project, we don't have a specific timeline :) I'd be happy if we have a mature circuit design and good code by Oshkosh time next summer so we have something to brief! As soon as we validate the AOA algorithm, we'll post the design and code on GitHub.

Since the components are so inexpensive, we have added an accelerometer pad that will provide future growth capability for additional overload warning. We want to experiment with 3 dimensional G sensing to provide asymmetric over-G warning (another great McDonnell concept used in the F-15) in addition to the aural AOA tone. We are also going to experiment with wing skin sensor ports (ala AFS stand alone AOA systems) and wireless sensors as well to determine what's in the art of the doable.

Mike,

GRT is in the TWS volume (i.e., in our cross-check), but the Gen 2 box is going to be a better option if we crack that nut!

Carl,

Thanks. We'll post a similar video with the new "analog" tone as soon as we get our test airplane modified and I have some time. Interestingly, Lenny (one of our world-class, way smart engineering types) came up with a way for me to actually adjust the wave pattern in the software, so what we are using now matches the sound of my piano. I figured that's a reasonable analog place to start.

It never occurred to me when we started this project that the tone itself would be an issue (guess I had flown with it too long and was simply biased), but we'll make sure there are user definable options (including a null tone, i.e., no sound when ONSPEED, although I would argue that operationally this isn't a good idea since the pilot does not receive continuous feedback) in Gen 2.

Johnnie,

We built the tone generator. The one in the video receives an AOA signal from a Dynon EFIS through serial output. Our "box" processes that signal and generates the tone pattern for the pilot. If you go back through this thread or search ONSPEED or ON SPEED (there's no right way to spell that) it might give you some more insight. We are now working on a 2nd generation box that will measure AOA and provide the tone. Our designs and software are posted on GitHub for folks that want to build one and we are standing up our own web site (flyonspeed.org) to consolidate all of our resources. We're also going to remain active here on the safety page.

All,

Our primary objective with the Gen 2 box is to eliminate or minimize calibration tasks for the pilot. Our biggest lesson learned is how varied commercial AOA system algorithms are, what the limitations of those algorithms are and that the average pilot has a difficult time getting the Dynon AOA system "dialed in." With the Dynon EFIS AOA display, it is essentially impossible to exactly replicate a calibration twice in the same airplane, using identical technique, under identical conditions. Simultaneously calibrating two identical EFIS (DY-10A's) even produced different results for each unit.

I have to point out the Dynon system does exactly what it's designed to do: provide excellent progressive stall warning. Turns out we were simply asking too much of that system to provide accurate AOA for ONSPEED or L/Dmax conditions with every calibration.

ONSPEED and L/Dmax only come into play when you use AOA to actually fly the airplane and assist with energy management as opposed to simply avoiding the aerodynamic (stall) limit. Besides demonstrating the utility of the tone logic, our other big objective is to provide educational resources so folks can develop a better understanding of how flying AOA not only helps avoid loss of control, but can really simplify precise control (energy management) of the airplane.

Cheers,

Vac
 
Last edited:
Johnnie,

We built the tone generator. The one in the video receives an AOA signal from a Dynon EFIS through serial output. Our "box" processes that signal and generates the tone pattern for the pilot. If you go back through this thread or search ONSPEED or ON SPEED (there's no right way to spell that) it might give you some more insight. We are now working on a 2nd generation box that will measure AOA and provide the tone. Our designs and software are posted on GitHub for folks that want to build one and we are standing up our own web site (flyonspeed.org) to consolidate all of our resources. We're also going to remain active here on the safety page.

Cheers,

Vac

Yes, last night I went through this entire post and realized what you were doing. I may be a bit of a simpleton, but I think the system in your video is perfect and wouldn't change a thing. When I read that it was an open source project, I was even more elated. I built a Stratux box a few years back and am still using and loving it. I will very soon be building one of your AoA tone systems to add to my -4. I am planning a GRT panel and will now likely add a small used Dynon box to run the tone (unless I can research and find out if it will work on the Sport EX that I plan on buying).

Thanks again for your innovation. Things like this make us all safer pilots. Now to hit the github and Amazon!!

Johnnie
 
Johnnie,

Drop a line or PM when you're ready and we'll help you with integration. If you are just starting your avionics upgrade, you might just want to hold out for Gen 2 and skip the Dynon D-10 unless it's going to be your back-up ADHRS source (it's a great EFIS for that purpose). It should theoretically work with the GRT serial output, but I don't think we'll be upgrading the code since we are going down the Gen 2 path instead--it's a better universal solution than trying to accommodate multiple manufacturer's outputs.

Cheers,

Vac
 
Last edited:
I have been using the first gen AOA for well over a year now and can't say enough good things about it. Just recently I went for a flight and didn't have it turned on, thought I made a good pattern but upon analyzing the dynon data realized making the base to final turn my onspeed aoa would have been beeping the Hi-Tone and I never even realized it, thought I was making a good pattern looking at my air speed.

Vac,
I can't wait to see what you and your team come up with in the future.
I'm sure it will be well worth the wait
Thanks again,
Dale
 
Hello my name is Jeff, I am a repeat offender, RV-7A RV-12, and I am addicted to my AOA Onspeed tone! Now that we have that out of the way. I am a beta tester for the Onspeed AOA project.

Just thought I would update the flying community. I have been flying with the Onspeed AOA for about 5 hours. We are on Version 2 of the software. Most of my time has been TO and Landings. I am getting dialed into the device and I love the way it works. I have heard there is a new generation in the works and I am looking forward to beta testing it as well.

If you are not familiar with this project go to Post 1 and start reading!
 
Johnnie,

It should theoretically work with the GRT serial output, but I don't think we'll be upgrading the code since we are going down the Gen 2 path instead--it's a better universal solution than trying to accommodate multiple manufacturer's outputs.

Cheers,

Vac

I have all GRT, and am curious of what "GRT serial output" you are referring? I dont know of a serial output for the GRT AOA signal, tho theres a lot I still learning about the GRTs.

Also I gather that youre making the gen2 a stand alone system. Is the plan for that also to be a DIY build and it'll just pick off the AOA pitot/static from an existing AOA probe? That would make sense, and I can see the benefit there.....

Any additional info greatly appreciated.
 
Last edited:
Hi Mani,

GRT interface was based on a cursory examination of a friend's system and the accompanying tech documents--There appears to be a serial out interface. It's been quite some time, so full-disclosure this is based on recall! This is similar to what we did with the Dynon serial out for our first generation demonstration system (i.e., we simply tapped into the existing AOA signal). The biggest issue we found using the "existing data stream" is that it is entirely calibration dependent--i.e., each Dynon calibration is unique. Don't know if you looked, but here's the circuit design and code for the first generation "serial data reader" version of the tone generator: https://github.com/dinglewanker/aoa-tone-efis-serial This design should be adaptable to any serial data stream.

Our 2nd generation system is stand-alone. It has pressure sensors on board as well as a more advanced processor. We are currently working on an AOA algorithm that will allow accurate measurement (1/4-1/2 degree resolution) at high gain change rates (up to 3-4 G's per second pilot input or 100-130 FPS gust load). We hope to be able to achieve this with very simple/minimal calibration.

So far, we've designed the circuit and have basic code. It took a while to work the data smoothing for the highly accurate pressure sensors, and we also capitalized on the digital to analog capability of the new processor to improve the quality of the tone. Now we are working on finalizing the AOA algorithm and calibration testing.

Here's a photo of the new system innards: https://drive.google.com/file/d/1oWLK6vM6jBlu_fBn0mzUk1iJ-9049bWK/view?usp=sharing. Here's the physics that makes it work: https://drive.google.com/file/d/1WELUD--STAb77zxNegIGNXtFioI3IFmX/view?usp=sharing
 
Last edited:
Hi Mani,

GRT interface was based on a cursory examination of a friend's system and the accompanying tech documents--There appears to be a serial out interface.

Thanks Vac. I'll look at the new info, but in the mean time, I asked Jeff at GRT (hes the top s/w guru there) about your first gen system and hooks in GRT, here's what he said...

"It should work with the "V-Speed ADS" serial output in the EFIS......[which is] one of our serial output options using the data format for the V-Speed ADS (a visual AOA indicator), which was originally designed for a Dynon data format. Set the baud rate to 115200 and set the Serial Port # Output to V-Speed ADS. We don't fill in all the AHRS data but it looks like the OnSpeed code only needs AOA and airspeed. Our update rate might be different though, and I didn't check to see if that would affect it."

Can you comment on if you think this would work given what Jeff says and what tone update rate Jeff mentions needs to be please?

Thanks for any info!
 
Mani,

That's the same baud rate that the Dynon serial output runs, and is comparable with the software. The only signal required is the AOA, and the current code for the first generation design processes the % lift signal from the Dynon. I imagine the GRT data stream is a slightly different configuration; so we'd have to take a look at that...

...why don't you PM with an email address or email directly to vacf15@yahoo dot com and we'll figure out what's in the art of the doable.

Cheers,

Vac
 
Mani,

That's the same baud rate that the Dynon serial output runs, and is comparable with the software. The only signal required is the AOA, and the current code for the first generation design processes the % lift signal from the Dynon. I imagine the GRT data stream is a slightly different configuration; so we'd have to take a look at that...

...why don't you PM with an email address or email directly to vacf15@yahoo dot com and we'll figure out what's in the art of the doable.

Cheers,

Vac

Thanks Vac. Standby for incoming.....
 
49clipper

I would love to integrate this system into my new build. Do I understand, that it is only drawings and text to build my own? Or will it be a kit, or? I just cannot buy one? I am terrible with building electronics no matter how simple.
Jim
RV-6/S-21
 
Excellent work!

Would you think this audible system would also be able to work off data provided by the Garmin AOA Pitot and EFIS? I'm planning on a full Garmin suite and sure would like to have this functionality. Thanks.
 
Jim and Mike,

Out of the box options for an accurate ONSPEED cue are Alpha Systems and MGL avionics at present. Our systems are currently "roll your own" for folks that are electronically inclined. The Alpha Systems probe and equipment is some of the best on the market and is completely stand-alone (i.e., separate from the pitot/static system). The "U-2 Aural Warning" option in the user configurable software provides the same logic as the F-4 warning we adapted for the ONSPEED system. As you can imagine, the U-2 is even more sensitive to precise AOA control during approach and landing than the typical fighter. MGL avionics also incorporates a pilot programmable mode that allows the use of the ONSPEED AOA logic with it's EFIS systems.

We do plan to test all commercially available AOA sensors with our new Gen 2 box (including Dynon, Garmin, Alpha Systems and AFS style wing ports and a simple, homemade pair of bent tubes on a Champ-class airplane) after we finish up the work with the algorithm that calculates AOA and validate the calibration technique.

We've started a non-profit (501[c]3) organization to help with this project, and open source all of our work. We are willing to provide the aural logic, circuit designs for our electronics, code, calibration or flight test data to anyone interested in incorporating the capability into their systems or that simply wants to collaborate on the project. PM or email vac at flyonspeed dot org if you're interested or just want to learn more about our work. We are cobbling together a new website at FlyONSPEED dot org, and will keep providing updates via VAF.

We are happy to work with any pilots, engineers, manufacturers or organizations that contact us--our objectives are to get the aural logic on as many AOA platforms as possible as a user selectable mode and get the word out on energy management through better training resources for the EAB community!

Cheers,

Vac
 
Last edited:
Would you think this audible system would also be able to work off data provided by the Garmin AOA Pitot and EFIS? I'm planning on a full Garmin suite and sure would like to have this functionality. Thanks.

Garmin already has an audio output feature for AOA, what features would this offer over the current garmin software?
 
Go back to the beginning...

Garmin already has an audio output feature for AOA, what features would this offer over the current garmin software?

Walt,
Please watch this video, which Vac's team produced back in the beginning of this effort: https://www.youtube.com/watch?v=-kbA6NxMpmQ

This is not a mere stall warning system: You already have that.

This projects the AOA range forward to give you audio cues of when you're maneuvering at Lift-over-Drag max and at the optimum AOA for maneuvering (best nose rate without excessive energy loss, which is also the optimum AOA for final approach). Does the Garmin do that?

I can also take you up in KELLI GIRL and demonstrate it with one of Vac's gen 1 boxes...I'm a tester. Using F-4 Phantom-style AOA energy management cues totally changes and improves the way you can fly your RV. My traffic pattern/landing ops are now near-perfect. Imagine the applications for aerobatics!
 
Last edited:
Yeah when I first watched the video presentation I envisioned it as a huge safety benefit for aerobatics and pattern operations, especially at high density altitude (hot and high) gusty days. This would be in a way a visual system can never compete with. Even with an ergonomically capable HUD presentation or eye glass HUD presentation, the audible translation is a valuable tool as one's focus can be anywhere yet valuable SA is still being provided.
 
Walt,
Please watch this video, which Vac's team produced back in the beginning of this effort: https://www.youtube.com/watch?v=-kbA6NxMpmQ

This is not a mere stall warning system: You already have that.

This projects the AOA range forward to give you audio cues of when you're maneuvering at Lift-over-Drag max and at the optimum AOA for maneuvering (best nose rate without excessive energy loss, which is also the optimum AOA for final approach). Does the Garmin do that?

I can also take you up in KELLI GIRL and demonstrate it with one of Vac's gen 1 boxes...I'm a tester. Using F-4 Phantom-style AOA energy management cues totally changes and improves the way you can fly your RV. My traffic pattern/landing ops are now near-perfect. Imagine the applications for aerobatics!

From a practical standpoint, I would never want all the info (noise) in my headset during "normal" (non-F4) ops. The garmin simply gives you a progressive audio tone from a point you set above stall (Caution-Alert setting which is usually about 1.1 above stall but can be anywhere you want) and then into the stall itself. Personally it does what I want for normal flying but I can see where Vics system may offer advantages for those wanting something other than basic AOA warnings. The Garmin does have visual speed clues similar to Vics, but does not extend the audio into that region.
 
From a practical standpoint, I would never want all the info (noise) in my headset during "normal" (non-F4) ops.

Nor do I. That?s why I plugged the AOA box?s audio lead into my intercom?s audio input, channel 1. When not needed, I switch to channel 3 and jam to my iPhone?s KELLI GIRL mix.
Righteous tunes, Dude!:cool:
 
From a practical standpoint, I would never want all the info (noise) in my headset during "normal" (non-F4) ops.

Thats why its on a rheostat - turn it up when you want it, turn it down or off when you dont.

For sure, not a panacea and not for everyone. But for the price of code, I want the mfg option to choose it.....or not....

Until then, I'll build it.
 
I like the rheostat option. I envisioned a switch for on/off control. I would not want the AOA tone going off all the time either. It would be managed like a before takeoff/landing/aerobatics flow-checklist item. The rheostat allows a nice volume control all in one.
 
I like the fact that is warns me if I get to slow in the turns in the pattern . I have my dynon D-180 configured for the earliest warning and it won't warn me that soon.
 
Gen 2 Onspeed Question - Display

Vac,

I really like the Gen 2 concept and packaging. Just out of curiosity. Are you intending to have some sort of visual display of AoA in this design?

-larosta
 
Last edited:
Visual Display

larosta,

Right now we're concentrating on the aural piece. We are adding a wifi interface and the ability to add accelerometers as well, so a visual display might be a future project (as will be aural cues for G and airspeed limits).

There is some scuttlebutt about an FAA standard for AOA displays, so I'm interested to see if that amounts to anything. What's different about our project is our system provides energy cues rather than simple progressive stall warning. The FAA is still trying to wrap its collective head around "energy management" and how those concepts apply to GA. It's always an interesting discussion any time you throw out terms like "angle of attack" or "energy management" in a GA setting. The bottom line with the aural logic is you don't have to be an expert in either to simply stop pulling when you hear the appropriate tone--can't make it any simpler than that unless you go to augmented flight controls.

We are still dialing in the algorithm that computes AOA from differential pressure. It took a bit to work out the math required to handle the 50Hz pressure mapping so we are currently flying with a "hard" AOA programmed in the code that is derived from airfoil analysis. Now that that's out of the way, we are moving on to calibration. Our objective remains 1/4-1/2 degree resolution of absolute AOA and good correlation with the thrust/power required curve up through Carson's Speed with caveman simple, accurate calibration.

I see from your profile that you're an engineer--drop a line or PM if you're interested in learning more about the new box or want to help out. We're non-profit, open source and always happy to share technical information.

Cheers,

Vac
 
Vac,

I may have missed it, but will the Gen 2 have the component/wiring diagram and code on Github as well? I think the only thing I've found on Github so far is the audio tone piece.

I like that it is an independent source of AOA so I don't have to buy a full EFIS. I found this today while researching using an Arduino to get the Pfwd/P45 ratio and interpret the AOA or max lift point from that (http://www.nar-associates.com/technical-flying/angle_of_attack/DFRDAS_AccurateLowCostAoA.pdf)
 
Hi Eric,

Yup--that's Dave Roger's paper and it forms the basis for our Gen 2 AOA logic. Dave has been gracious enough to help us out as we develop the system. We'll publish the design for the Gen 2 once we finalize it--we're close, but we are adding some test points to the board and want to build three and test them before we publish the design. We are starting a website at flyonspeed.org and we'll post all of the information there and we'll also update the GitHub site.

Here's a couple of photos of the system described in the paper

view


view


The test rig is on a standard RV inspection plate and will fit in any -7/8/9/10 or 14.

The Gen 2 system marries up the software in the paper you reference with the ONSPEED aural logic. At the moment, we are partnering with the folks at Spin Garage to modify one of there nifty flight test booms to talk wirelessly to the Teensy processor in the Gen 2 box--this will allow us to marry up the flight test data real time.

Our objective is to have the baseline AOA and aural tone working on the final board configuration by OSH time next summer so we can start beta test. We are also looking at collaborating to determine what's in the art of the doable to build boxes for folks that aren't interested in building their own system, and we added some accelerometers to the board for future growth capability.

If you drop an email to vacf15 at yahoo dot com, I'll be happy to share a Gen 2 schematic with you.

Cheers,

Vac
 
OSH Forums

Hi Folks,

Team ONSPEED will have a small booth in the EAA Innovation pavilion (IC-29) and will be conducting a couple of AOA forums. Our skunkworks will be talking about our HUD project as well. We'll be sharing lesson's learned and technical information with anyone interested. We will have some hardware and simulator displays at the booth. We are a non-profit, open source group and happy to chat with anyone interested. We are getting close to finalizing the hardware configuration for the "Gen 2" AOA computer and just shoehorned all of the latest/greatest equipment into the Jurassic RV-4 test bed. When we do finally declare configuration victory, we'll get a GitHub site set up for collaborative software work and update the hardware info on the flyonspeed.org website. The plan is to be in beta test with the new hardware this fall--we'll see how that plan survives all the foibles of a bunch of volunteers with good intentions :D

Our AOA forums will be Monday, 22 July 1300-1415 in Workshop Classroom B and Friday, 26 July 1430-1545 at Forum Stage 1. During the AOA forums, we?ll talk about what ?ONSPEED? AOA is and how it?s applied during flight. We are also working on an F-18 inspired DIY HUD and will be conducting a forum on that project on Thursday, 25 July 0830-945 at Forum Stage 3. We look forward to meeting anyone that wants to talk AOA, Heads Up Displays, warning systems, energy management, RV?s or just share a beer and spend some quality time shooting down watches.

Another part of our mission is to develop and maintain the RV training resources that Doug so graciously hosts here on the VAF Safety Page. We are always happy to chat with any instructors or folks undergoing transition training that can use those resources.

And, as always, we are looking for feedback and happy to accept any critique or collaboration.

Happy 4th of July,

The FlyONSPEED Team
 
Aural AoA demo flight

I am a RV-4 owner and also a test pilot for one of the large airliner manufacturers. Today I had the opportunity and privilege to fly a demo/data gathering flight in Vac's RV-4, which is equipped with the audible AoA tone system. I wont bother to describe the system in this post, as there is plenty of information and links about it already on this thread. But here is my impression of the concept as integrated so far:

Love it! It provides an intuitive cue to flying your plane at the most appropriate AoA for the phase of flight without having to think too much about it. The learning curve for adapting ones flying technique to incorporate this device was measured in mere seconds for me. I did not find the tones intrusive or distracting at all and they allowed me to keep my eyes out of the cockpit significantly more for orientation, trajectory control and traffic acquisition.

Once I was out in the operating area I carried out a couple of gentle, level decelerations in both clean and full flap configurations. This got me familiar with the tones/beeps and the airspeeds that they occurred at in level flight. Then it was on to the fun stuff: maneuvering and basic aerobatics. It was a joy to be pulling smoothly around the puffy cumulus clouds which were forming at around 5000ft, in a loose sequence of wingovers and lazy-eights, all flown on the reassuring on-speed tone with my eyes firmly out of the cockpit. A couple of loops followed, and I found that when the on-speed tone changed to the higher pitch "too-slow" tone over the top of the loop, all I needed to do was to relax the back stick pressure a little to regain the on-speed tone. Eyes stayed out, looking for the horizon to come into view and there was the nice reassurance that I was not about to depart the loop into a stall or spin.

Back in the visual pattern, flying the on-speed tone around a 180 continuous base turn and then down final was a piece of cake. A couple of times the tone changed to either "too slow" or "too fast" but a small pitch input with the stick quickly brought us back "on-speed". Which, when you think about it, is consistent with how we were all taught to control speed on approach in a GA prop plane: adjust speed with the stick and adjust rate of descent with power. As you start the flare, you just let it transition to the slow tone down to touchdown. The system is so impressive, you almost have to remind yourself that this technology only assists with angle-of-attack/speed: trajectory control, ground track, wind allowance, etc is still up to you. But now I think you have freed up some brain capacity to fly more accurate, consistent patterns and look out more.

All-in-all, it's a win-win enhancement for safer flights.

Bruce Macdonald.
 
Last edited:
I am anxiously awaiting the 2.0 stuff, either to buy or build. This is a great addition to flight safety.
 
I can also take you up in KELLI GIRL and demonstrate it with one of Vac's gen 1 boxes...I'm a tester. Using F-4 Phantom-style AOA energy management cues totally changes and improves the way you can fly your RV. My traffic pattern/landing ops are now near-perfect...


I'd love to try it in real world conditions if possible.


Here's a couple of photos of the system described in the paper

view


view


The test rig is on a standard RV inspection plate and will fit in any -7/8/9/10 or 14.

I'm planning on installing my Dynon heated AOA pitot tube on the inspection plate too but this removes the headache of installing a new 1/4" tube from the wing all the way to the panel in an already built plane.

Should I hold up on buying the Dynon pitot and just build this stand alone instead or is this setup in addition to the Dynon heated AOA pitot tube?

Would another option be to use a Dynon heated AOA pitot with the Gen1 system and turn down the volume of the Dynon AOA and only use this audio?

I'm wanting to install a heated pitot tube so I still have some doubts on how all of this comes together.
 
Last edited:
Hi Carlos,

The Dynon pitot heat unit and our computer could be bolted to an inspection plate, as long as there is no interference with your aileron bellcrank. I have one of our computers on my inspection plate in the RV-4, but I pulled the pitot heat unit out to have sufficient space and re-purposed the wiring going to the cockpit so now my Dynon probe is unheated; which is fine for flight test work. It's not too difficult to run an additional 1/4" flexible tube to the cockpit, which would allow you to use one of our computers in lieu of the Dynon progressive stall warning tone. If you're handy with a soldering iron, the Gen 2 has a lot more capability than Gen 1; but the Gen 1 will give good baseline AOA performance in the RV-3/4/6/7/or -8.

My 2 cents would be to install the heated pitot and control box were it makes most sense to you and run wires/tubing to the cockpit and hook up the basic Dynon AOA system in accordance with the Dynon installation manual. After that, you can add a Gen 2 (or Gen 1 box) with minimal fuss.

Since there is an IMU (inertial measurement unit) in Gen 2, it's nice if its roughly on the longitudinal axis of the airplane. This isn't required for AOA, but may be for future capability we are adding to the system.

Happy to help, feel free to email or PM any time.

Cheers,

Vac
 
Last edited:
Hi Carlos,

The Dynon pitot heat unit and our computer could be bolted to an inspection plate, as long as there is no interference with your aileron bellcrank. I have one of our computers on my inspection plate in the RV-4, but I pulled the pitot heat unit out to have sufficient space and re-purposed the wiring going to the cockpit so now my Dynon probe is unheated; which is fine for flight test work. It's not too difficult to run an additional 1/4" flexible tube to the cockpit, which would allow you to use one of our computers in lieu of the Dynon progressive stall warning tone. If you're handy with a soldering iron, the Gen 2 has a lot more capability than Gen 1; but the Gen 1 will give good baseline AOA performance in the RV-3/4/6/7/or -8.

My 2 cents would be to install the heated pitot and control box were it makes most sense to you and run wires/tubing to the cockpit and hook up the basic Dynon AOA system in accordance with the Dynon installation manual. After that, you can add a Gen 2 (or Gen 1 box) with minimal fuss.

Since there is an IMU (inertial measurement unit) in Gen 2, it's nice if its roughly on the longitudinal axis of the airplane. This isn't required for AOA, but future capability we are adding to the system.

Happy to help, feel free to email or PM any time.

Cheers,

Vac

I replied to your email but now that I?ve read your post here I?m convinced talking is better than writing because I?m either missing something here or I?m not communicating what I want correctly.
 
Carlos,

I sent an email--hopefully I got it right this time! If not, feel free to call.

Cheers,

Vac
 
Still missing my point :confused::)

No worries I?ll go back to the website and start my research over again to see if I can figure it out. Thanks.
 
Back
Top