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ON SPEED Angle of Attack Video

Vac

Well Known Member
Benefactor
Hi Folks!

Over the past year, we have been experimenting with an aural AoA system. I thought an RV-focused training video that illustrates how ON SPEED can be applied during different phases of flight might be of interest to some of the folks in our community:

https://youtu.be/-kbA6NxMpmQ

There are FAQs at the end of the video that answer some of the questions we've had about the system, the most prevalent of which is "is the tone that loud in the cockpit?" (no, it's not). I included a short clip that attempts to convey what the aural system sounds like at ambient cockpit noise level.

We are continuing to experiment with different user configurations, but this video uses the standard aural logic that allows the pilot to hear the entire back side of the drag curve, as I thought that is the best way to convey some of the basic concepts of flying AoA. I realize the airspeed/AoA debate has been raging since about 1903, but the purpose of this training video is to simply illustrate the concept of flying ON SPEED, and how it's applied as a technique to help maintain aircraft control and optimize performance. The tactical advantage of an aural system, is that you don't have to look inside the cockpit.

If you've got a properly calibrated AoA system in your RV, you can achieve much, if not all of the utility demonstrated in the video.

Fly safe,

Vac
 
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AOA

Awesome video and demo, Mike! Those of us who flew AOA back in a previous life know flying AOA makes soooo much sense. I knew F-4 was first to use tone set up; were there others? None of the Navy stuff I flew had tone, just the glareshield index and panel steam gauge.
The tone system has so much safety potential for this community (works well in a dogfight too), we could really use an out of the box solution here.
Thanks for posting, will be looking for more!

BTW - love your "gear down" CTAF call in the pattern - you can take a guy out of the military, but you can't take the military...........

Doug
Seattle area, -4, wings
old A-6 guy
 
Great work Vac.

Would be great if Garmin, AFS, Dynon, GRT, MGL, etc. incorporated this in their EFIS.

Sounds like a simple DIY project for Dynon users. I am wondering how much work it would take to get it to work with all manufacturers stuff.
 
Great

introduction to AOA aided maneuvering. When I get to fly my Dynon system I know I will be envious of your tone logic, but I think the basics apply to the plain Jane Dynon system. Another arrow in the quiver of flight safety.
 
Impressive Mike, thanks. A real time and spot on commentary! I like the little image of you in the AI during maneuvering.

I flew on the gulf coast out of Brookley in the mid 80's and my instructor got me to saying "gear down and locked" as cleared for the approach as many of the controllers were military and accustomed to hearing it. Even for the 182.
 
AOA

Mike, I notice that you are using one of the serial outputs from the Dynon 10A. Can you tell me which one, serial 1 or serial 2 ?
Val k
RV8
N81VK
 
Serial Output

Hi Val,

The DY-10A only has a single serial output. The two EFISs (plural?) are networked, but I'm only using the signal from the network master. I don't believe that the DY series shares AoA over the DSAB network. We tapped into the existing pigtail D9 connector normally used for data download and software updates.

This is shown in the upper right of the schematic on page 2-2 of the EFIS-D10A installation guide.

We put a serial connector on the tone generator to allow fitting a simple cable.

Cheers,

Vac
 
AOA

Thanks Mike,
I noticed that pin 13 0n the D25 connector is identified as Serial 2TX. This prompted my question.
If I proceed with this project I will use Serial 1 which is also used by my SL30, this I assume would work since I believe this serial port can support several things, at least two.
Val k
RV8
N81VK
 
Val,

You are correct. That port is actually wired to the altitude encoder in my plane, and I had forgotten about that until I looked it up in the drawings. We had to record data during flight test as we were developing the software, so we just used the existing pigtail.

Drop me a PM or e-mail and we can chat about AoA calibration/data reduction for the DY if you decide to build a tone generator.

Cheers,

Vac
 
G3x aoa

For what it is worth, if properly calibrated as per the manual, the Garmin aoa associated with the G3x does pretty much the same thing. Not quite as nice as this but darn close and very useful if you grew up with a tone system. It really is almost a must have for me so I can keep my head out when maneuvering,in the traffic pattern and shooting approaches. Sometimes passengers get concerned if they hear any kind of beep, so be prepared for that.
 
AOA

Mike,
I will take you your on your offer. I am planning to proceed with building the tone generator but it may take a little while since there are a few other projects to get out of the way.
A question was asked as to the cost. I would estimate it would easily take less than $50 for all components and probably less. The instructions on the web site are more than adequate but may require a little bit of head scratching for some, but it is certainly doable.
I am currently flying with the Dynon AOA but find it almost useable due to the fact of having to constantly look into the cockpit to reference the AOA. Flying the "tone" seems a bit more practical since it enables your eyes to look outside the cockpit and still stay "on speed". I look foreward to building and flying this device.
Val k
RV8
N81VK
 
Mike,
I am just finishing up my PPL cert. and this maybe one of the most helpful videos I have seen to understand efficiency in flying. No kidding.

This is just awesome to a novice like me. I get to see and hear how it is done.

Thanks for this Sir!
 
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If someone could make these available commercially so that it worked with the Skyview, I'd buy one immediately!:D
 
More than one way to skin the cat...

Any properly calibrated system that provides graphic or aural information is going to provide some or all of the utility of the F-4 logic, as long as you can "fly the green doughnut" (appropriate chevron or LED)!

MGL has incorporated this logic in a user-configurable module, so if you have an MGL system, it's practical to calibrate it and use the logic just as it's presented in the video.

One of the objectives of developing the video is to simply show folks how AoA can be applied during maneuvering flight, regardless of how the information is conveyed to the pilot. I think the F-4 aural logic has some merit for an educational video, since you can see the airspeed indicator, pilot's view and simply listen to the AoA simultaneously.

The ability to maneuver "eye's out" is something that I value highly, but a well integrated graphic display in a proper instrument cross-check can provide much of the utility. And, depending on calibration and set-up, some portions of a "progressive stall warning tone" that most of the EFIS/AoA systems provide may correspond to ON SPEED or provide a good approximation.

In swept-wing jets, just about everything good happens at L/Dmax; but straight wing props are a bit different, so as an instructor, I find a huge amount of utility in being able to provide precise feedback based on knowing EXACTLY where we are on the back side of the drag curve; and the way we apply the baseline F-4 logic is simply one way to do that.

Since a tone system is something unusual for most folks, I recommend watching parts of the video multiple times to internalize the concept and work past any first impressions of distraction. In the end, it's really a lot like listening to music while you do something else; but it does take some getting used to, and isn't for everyone.

I'm also biased after a couple of thousand hours of flying with this logic, which is an experience set that I understand most folks don't have. I have no doubt this bias affects my objectivity; so I'll leave it up to folks to decide for themselves if there is any utility for them using this or similar logic. And I think there is plenty of room for looking at improved ergonomic alternatives!

For folks that may be interested in the aerodynamics and history of differential pressure AoA systems; and the engineering math we used to help adopt the tone logic for an RV, this is an interesting (old) report:

https://archive.org/details/DTIC_ADA035321

Fly safe!

Vac

P.S. Mark--this logic does work with the SkyView and we've built a prototype that is compatible, but haven't tested it yet. I believe the SkyView uses an improved AoA algorithm, and likely produces more consistent calibration results than the earlier DY equipment does. In theory, it should be easier to program the tone generator for a SkyView system; but we'll have to complete testing to determine if that's the case.
 
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Great video, and inspired me to go do some practice today using AOA. I have the derived AOA on my GRT Sport, but have actual AOA plumbed to my Dynon D10. I haven't been using the AOA display from the D10 as it is not my primary instrument and I don't generally look at it on approach. This thread has convinced me to build and install the tone generator which should be a perfect solution for me.

What I re-learned while practicing today was that I have let my approach speeds get too high. The day I did my first flight, I found a full-flap stall speed of 44KIAS, so I flew my approach at 60 knots, and it worked great. I've flown as slow as 55KIAS for short field practice without incident, also. In the year since then, I am guilty of letting my approach speed creep upwards for various reasons (gusty, crosswinds, heavy, etc) until I found myself generally flying final at 65 KIAS. This is almost always too fast and results in too much float, which means more time for something to go wrong, too.

Flying with and paying attention to AOA today I found myself back at 58-60KIAS, and nailed some spot landings, even with a 5-7 knot x-wind. There was still plenty of energy left for a flare and gentle touchdown.

I obviously don't fly any crazy flight regimes in my 9A, but any tool I can use to make me a more precise, safer pilot, I am all for. The ultimate goal is to fly the same perfect, precise, stabilized approach to land, every time. The 9A is so forgiving, it let me get away from that perfection without really noticing.

Thanks

Chris
 
interesting document

Mike, Thanks for the link to the document. I found this amazing:

19. Schuck, 0. H., "Angle of Attack Indicating Device," U. S. Patent No. 2,948,149, Aug 9, 1960.

Almost 60 years and we still struggle to get this very useful safety feature in all aircraft.
 
P.S. Mark--this logic does work with the SkyView and we've built a prototype that is compatible, but haven't tested it yet. I believe the SkyView uses an improved AoA algorithm, and likely produces more consistent calibration results than the earlier DY equipment does. In theory, it should be easier to program the tone generator for a SkyView system; but we'll have to complete testing to determine if that's the case.

Thanks. Can't wait to learn more!
 
should work already with a setting adjustment

If someone could make these available commercially so that it worked with the Skyview, I'd buy one immediately!:D

The Skyview AOA system is based on the calibration that you fly... typically the target point is a specific configuration stall and the audio trigger points. From the Config file, there there are two settings that indicate the start of sounds and the start of the solid tone:

audio_sound_aoa_start_thld=50
audio_sound_aoa_solid_thld=95

I believe that you can simply adjust the start threshold from 50 to have the tones begin at the desired 'On Speed' target.
 
Find 60% Lift

Stephen is correct that the progressive tone can be adapted to provide an approximation of ON SPEED.

Most basic technique:

Calibrate your AoA system in accordance with instructions. If you aren't sure about what the system is sensing for stall (i.e., you can down load data from an EFIS, but you can't from a stand-alone AoA sensor), just do some comparison flying--check your AoA indications against Vref at 1G in different flap configurations (or Vx or minimum sink glide, if you've got that information) and correlate any display or audio cues. That will provide a rough approximation of ON SPEED. This technique will work if you have steam gauges and an AoA sensor of some type.


More in-depth considerations:

Measuring actual AoA is a black art! All we are doing is using our differential pitot pressure sensor as a surrogate--that will get us close enough for every day life; but calibration still presents some challenges...

ON SPEED occurs at about 1.3-1.4 times the stall speed for an RV, so you know about what IAS to look for at 1G as you set up any system.

Calibration of differential pressure AoA systems "teaches" the software where 100% lift is, and the indication and progressive stall warning is based on what percentage of lift is being measured. Since ON SPEED occurs at approximately 60% lift, if your calibration has stall occur at 100% lift, then the 50% audio trigger point Stephen mentions would be just a bit faster than ON SPEED, but reasonably close. If the tone is progressive, and you slow from the point the tone starts (50%) to Vref, whatever the tone sounds like at Vref is about right.

The older DY Dynon systems have the option of starting audio at the bottom or middle of the yellow band--depending on calibration, likely one of those settings is going to be very close to ON SPEED if (big if), the stall is occurring at 100% lift as sensed by the EFIS.

On the other hand, if the calibration has stall occur at 85%, then the 50% start of the tone is roughly equivalent to ON SPEED. It's simply proportional.

If your system is calibrated, and the manufacturer provides data about how the graphic display works, you can determine where ON SPEED is. For example, if it's an AFS pro, then ON SPEED is the green doughnut (the doughnut is the classic military standardized solution for displaying ON SPEED). Other systems use a similar logic. On the other hand, if it's a progressive display (chevrons, LEDs, etc), then you may have data about how that display works in terms of % lift; so if you've calibrated so that stall is occurring at 100% lift, then whatever portion of the progressive display corresponds to 60% is what you are looking for to approximate ON SPEED.

For experimenters that have an EFIS:

The first step is to calibrate the AoA system in accordance with the manufacturer's instructions, and then fly a stall series and record the data. Set your EFIS data recording system to 1 second intervals--that's sufficient.

It is sufficient to fly stalls in three configurations: flaps up, half flaps and full flaps. Set the altimeter to 29.92 and fly a representative pressure altitude. The simplest technique is to select idle power and maintain altitude precisely. Trim as the airplane decelerates, but stop trimming at about 80-90. After the stall, use AoA to recover (i.e., pitch down) and let the airplane recover at idle power and accelerate to about 100 MPH/90 KTS indicated (just a bit faster than trim speed)--you'll lose a few hundred feet of altitude (which is fine, since our objective is to generate an easy to read graph, not pass a check ride). Once you've accelerated to about Vfe ish (that's where the 100 MPH/90 KTS ROT comes from), add power, climb up and get set up for the next iteration. This isn't a speed drill--about 45-60 seconds per stall should work out about right.

After you land, download the flight data. Find the stall series in the data (use a data marking function if your system allows or a time hack to help find the information). Plot % AoA and IAS vs elapsed time--look at what the AoA/pitot is sensing vs stall and figure out what the peak AoA % value is for various configurations. In an RV, it's sufficient to look at flaps up, half flaps and full flaps. The data from this test drill will allow you to program the various tone trigger points if you are building a tone generator.

If you don't provide a flap position sensor that tells the computer which data curve to generate tone from, you can still approximate ON SPEED in a landing configuration (where you obviously want the most accuracy) and accept some error during maneuvering flight (where all it's costing you slightly reduced accuracy in sustained turn performance feedback).

Fly safe,

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!

https://www.eaa.org/en/eaa/eaa-news-and-aviation-news/eaa_founders_innovation_prize
The 2017 EAA Founder’s Innovation Prize is a contest to solve the problem of fatal loss of control accidents in amateur-built aircraft through innovation. The contest is intentionally open-ended, with the only stated goal to reduce fatalities from this type of accident in amateur-built aircraft dramatically over the next decade - 25% in the next five years, 50% in the next ten. Submissions are due June 15th, 2017.

Goals and Criteria

Loss of control (LOC) in flight is the leading cause of fatal accidents in general aviation, particularly in amateur-built aircraft. Fatal LOC events include base-to-final stalls, departure stalls, loss of control while maneuvering, spatial disorientation, and more. The 2017 contest seeks ways to solve this problem. The solution could be technical in nature or otherwise.

The judging criteria include:
•Effectiveness in reducing LOC occurrence, including wide applicability to the experimental amateur-built fleet and maturity of the solution
•Low Cost
•Ease of installation/implementation

Prizes

The winning individual or team will receive a prize of $25,000, with $10,000 awarded for second place, and $5,000 for third. The five finalists will also be featured in EAA media leading up to the final award.
 
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!

https://www.eaa.org/en/eaa/eaa-news-and-aviation-news/eaa_founders_innovation_prize
The 2017 EAA Founder?s Innovation Prize is a contest to solve the problem of fatal loss of control accidents in amateur-built aircraft through innovation. The contest is intentionally open-ended, with the only stated goal to reduce fatalities from this type of accident in amateur-built aircraft dramatically over the next decade - 25% in the next five years, 50% in the next ten. Submissions are due June 15th, 2017.

Goals and Criteria

Loss of control (LOC) in flight is the leading cause of fatal accidents in general aviation, particularly in amateur-built aircraft. Fatal LOC events include base-to-final stalls, departure stalls, loss of control while maneuvering, spatial disorientation, and more. The 2017 contest seeks ways to solve this problem. The solution could be technical in nature or otherwise.

The judging criteria include:
?Effectiveness in reducing LOC occurrence, including wide applicability to the experimental amateur-built fleet and maturity of the solution
?Low Cost
?Ease of installation/implementation

Prizes

The winning individual or team will receive a prize of $25,000, with $10,000 awarded for second place, and $5,000 for third. The five finalists will also be featured in EAA media leading up to the final award.

Noah that is a GREAT Idea. I agree with your assessment and thank you for suggesting it.
 
Thank You

Folks,

I appreciate all of the replies, discussion and interest in our work!

We are happy to share everything that we've learned with ANYONE interested in building a tone generator, adapting this logic or just interested in discussing the concept. We have only been working on this project for a year, and still have some legwork to do to improve utility and accessibility for folks that may want to experiment or use a similar system. We aren't a commercial concern--just some of RV'ers that like to experiment.

What's nice about the concept is that it's just an aural logic--it can be "ported" to any AOA system if a manufacturer chooses to adapt it. Furthermore, it is really a "CAWS:" Caution and Warning System...there may be a better, more ergonomic method of conveying ON SPEED information to the pilot; or the logic could be integrated with other envelope protection. It's completely feasible to provide distinct, ergonomic aural warning for the entire flight envelope (aerodynamic, G and airspeed limits). Providing ON SPEED cues simply enhances the the system by providing an optimum performance cues as well. Pieces and parts of this already exist in currently available hardware; so it's a matter of adapting and integrating, as well as ensuring simple, effective calibration and education of pilots. Similar systems have proven effective in high-performance trainers and fighters, and if we are trying to mitigate loss-of-control, it's worth looking at what has worked in other flying communities faced with a similar challenge.

Any and all comments or questions are welcome. Please feel free to post, e-mail or PM. And please consider commenting regardless of your experience! One of our primary objectives is to help inexperienced folks safely transition to RV's and learn how to safely operate the airplanes throughout the flight envelope, and those folks have an outstanding perspective to offer valuable feedback.

The objective of this project is similar to the objective of preparing high-quality training resources: a community-based "self-help" project. In that spirit, I appreciate the point out the EAA Founder's Innovation competition. We did, in fact, apply last year without success; but have had several months to continue test and evaluation of the concept and will be re-entering this year. Competition aside (this isn't football or combat), hopefully participation will at least engender continued discussion and introduce more folks to the potential benefit of this of this type of "non-automatic" solution to mitigate loss-of-control mishaps.

Thank you!

Vac
 
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Short Video

For those folks not interested in enduring 17 minutes of instructor commentary, I've edited a shortened version of the video with some new footage. It provides a good 30,000 foot overview of the ON SPEED concept, and also includes "botched pattern" demonstrations where the tone assists with proper energy management when correcting pattern errors.

Please note, that in a couple of the demonstrations, I'm max performing the airplane in close proximity to the ground (under controlled conditions) to demonstrate how the tone logic assists with energy management. I don't advocate ever trying to salvage a bad pattern--it's far safer to go around. When I teach, in my personal and professional flying, I use a simple decision matrix: "if there is a doubt, there is no doubt..."

The purpose of the demonstrations is only to show how the tone logic assists the pilot with maintaining aircraft control under demanding pattern conditions, including "worst case" low energy conditions. Keep in mind that any departure from controlled flight below pattern altitude is likely to be unrecoverable.

Here's a link to the short video: https://youtu.be/BCQF8B49tgw

As always, any comments or critiques are welcome and hopefully the information may be helpful for some of the folks in our community.

Fly safe!

Vac
 
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Any and all comments or questions are welcome.
I have an AFS Sport AoA system in my Lancair 235, and would be nervous flying without it. I have to admit that the AoA has saved my bacon a couple of times. The Lancair is not known for its gentle stall characteristics. That said, I think the constant beeping on final approach would be very annoying, although I suppose one could get used to it. As I'm sure you know, the AFS Sport unit has an LED bar graph which indicates the same things that the various "fast" tones do in your system. I mounted mine just to the left of the ASI so it's in my peripheral vision when checking my airspeed. They also have displays that can be mounted on the glareshield. The only time I get an audible stall warning is when I get within 5% of a stall. The Sport unit also alerts me when I get below 95 Kts with my gear up - a real bonus in a retractable. The CPU also has two "tables" used to compute the stall speed - one in the clean configuration and another in the landing configuration. Short video:

https://www.dropbox.com/s/yx1kabddx9ihwtq/2017-05-03 full flare landing_0261 (1).mp4?dl=0
 
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All AOA Systems Assist EM

The Lancair video is an excellent example of effective energy management for landing using an AOA system! Properly calibrated, the AFS systems provide outstanding ON SPEED/slightly fast/slightly slow cues in addition to stall warning (albeit mostly visually, requiring the pilot to look at the indicator), and can provide the same utility as the tone logic. Any AOA system, properly calibrated and understood can provide that utility.

A few thoughts on the aural logic. I think there is good benefit in "eye's out" concepts that assist with energy management, and the current tone logic in the demonstration videos (reverse engineered from the F-4, which, like a Lancair, had limited aerodynamic warning of stall) is only one way to accomplish that. The comment regarding the tone pattern being annoying is the single most common reaction I get when showing folks video demonstrations of the system and in discussions regarding the logic. While I recognize my own bias, using the system in real life is a bit of a green eggs and ham proposition, however. I don't get the same feedback in the airplane after folks have a bit of time to become acclimated and try the system in an operational environment at ambient noise levels; and, historically, the system proved effective in military use. It's also got a volume control and an OFF switch! We are also experimenting with providing more control over which parts of the tone logic are active (i.e., pilot selectable) and use of a "null" tone for ON SPEED.

One of the most important objectives of our experiment is simply to increase awareness of the tactical utility of understanding and incorporating AOA cues in daily flying. The previous post is an excellent example of that, and I really appreciate the great discussion. Thanks much for taking the time to thoughtfully comment and share the video!

Cheers,

Vac
 
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AOA

I totally understand the benefits of using the AOA system for better energy management. I for one have not been a fan of the visual system simply because I do not like looking into the cockpit or on the dash at another gauge but prefer to keep my eyes looking outside and flying the plane. I have watched your videos and very impressed with the audio input system. It reminds me of listening to the flying wires on bi-planes for speed inputs I've had the pleasure to fly. Yes, the pings, buzzing high and low can be annoying but you seem to be refining the system to be quite compatible with landing or aerobatic work load. I was flying today in very gusty conditions and would have enjoyed the extra help. I look forward to trying your system in the near future. Please keep up the good work!

Rod Estep
RV-8
Dues paid
 
Vac and I have been trading notes on his system throughout its eveopment, and I am a huge fan of the aural method of AoA awareness. I am also a big fan of the "null tone" when you're on speed because I don't want a continuous tone in my ear when everything is alright in a potentially radio-busy environment at uncontrolled fields, where you need to be concentrating on traffic as well as your AoA state.

I have both the Dynon and Garmin systems we fly set for a very slow beep in the on-speed condition, so if I start hearing an excited beep, I know I am getting slow. We also have Alpha Systems and AFS units installed in various planes, and they are set with discrete voice calls ("Getting Slow", "Too Slow", and "Angle, Angle, Push!") which don't help as much as a tone (or frequency) that tells you where you are in the spectrum in an analog fashion, not just discrete points.

Regardless of what works best for you, I am convinced that AoA is the single best way of managing to stay out of the stall regime when you don't want to be there. And yes, I flew without it in light planes for most of my career - so I can feel a stall coming on. In most plans. Some, however, have almost no aerodynamic warning - especially in the homebuilt world - so AoA might very well save your bacon, even if (or because) you are an old-time pilot.

Old Dogs, New Tricks....

Paul
 
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ON SPEED Angle of Attack

This is my first post but I've been following VAF for years.
My son and I are partners in our RV-7A we built. It has a dynon d-180.
I bought the arduino due board and knowing nothing about it and the software it uses with just minimal research it was easy to get the On Speed software installed. Once that is done just a matter of hooking it to the serial output of the dynon.
Vac and I have been emailing back and forth to fine tune the software to my particular aircraft. He has answered any question I have had!
I am still watching my airspeed indicator but not nearly as much as I did. (eyes looking outside) The more I use it the more I am trusting it!
In the video the tone sounds loud but actually using it its just in the background, plus I have a volume control.
Anyone thinking about building and using this system should hop on board.

Cal
 
AOA

Mike, if your well done video doesn't make believers in the value of AOA I don't know what will! Extracting max performance from our airplanes is paramount as is safety in operation, thanks again.

Mark
N819MW
RV8
 
Recut video

I re-edited the long "how to" ONSPEED video, incorporating the pattern corrections that I had originally recorded for use in the short demonstration video. I think this makes the video a bit more valuable as an introduction to "how to fly ONSPEED." To make the tone audio easier to hear, all of the demonstrations on the long video have engine noise edited out.

The new version is available via this link: https://youtu.be/-kbA6NxMpmQ

There isn't any new footage, it was just a matter of adding portions of the short video that hadn't previously been incorporated in the longer version...

For folks interested, we will conduct a forum at Oshkosh on Friday, 28 July at 2:30-3:45 PM (Forum Stage 1) discussing ONSPEED concepts (including flying ONSPEED with any AoA system), aural AoA logic, building tone generators and using the aural logic with MGL EFIS systems.

Fly Safe,

Vac
 
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For folks interested, we will conduct a forum at Oshkosh on Friday, 28 July at 2:30-3:45 PM (Forum Stage 1) discussing ONSPEED concepts (including flying ONSPEED with any AoA system), aural AoA logic, building tone generators and using the aural logic with MGL EFIS systems.

Will a recording of that presentation be available later, for those who can't attend?
 
Vac and I have been trading notes on his system throughout its eveopment, and I am a huge fan of the aural method of AoA awareness. I am also a big fan of the "null tone" when you're on speed because I don't want a continuous tone in my ear when everything is alright in a potentially radio-busy environment at uncontrolled fields, where you need to be concentrating on traffic as well as your AoA state.

I have both the Dynon and Garmin systems we fly set for a very slow beep in the on-speed condition, so if I start hearing an excited beep, I know I am getting slow. We also have Alpha Systems and AFS units installed in various planes, and they are set with discrete voice calls ("Getting Slow", "Too Slow", and "Angle, Angle, Push!") which don't help as much as a tone (or frequency) that tells you where you are in the spectrum in an analog fashion, not just discrete points.

Regardless of what works best for you, I am convinced that AoA is the single best way of managing to stay out of the stall regime when you don't want to be there. And yes, I flew without it in light planes for most of my career - so I can feel a stall coming on. In most plans. Some, however, have almost no aerodynamic warning - especially in the homebuilt world - so AoA might very well save your bacon, even if (or because) you are an old-time pilot.

Old Dogs, New Tricks....

Paul

I developed visual glareshield AoA indicator for the D10x about 10 years ago and sold a bunch. However, I was not thrilled with a visual indicator. When Dynon introduced their progressive audio tones for AoA, I felt this was a superior, safer way to indicate AoA so I discontinued my product.

I did develop a haptic stick shaker as well and provided one for FAA flight safety evaluation. I found this was an effective indicator.

However, I really like Vac's On-Speed concept. Even just as a training aid, it will make you a better pilot. Perhaps it could be simplified to make it less intrusive to passengers, but for solo flying, it seems awesome. The hardware is simple and using the Arduino platform seems to be the way of the world now.

I've been drinking the Arduino Kool aid(tm) for a while now and have converted PIC microcontroller designs to Arduino. Perhaps a bunch of Kit Planes articles can be harvested from the VAF community. Cool stuff.
 
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Forum Video

Bob,

I'll check with the folks at EAA regarding the feasibility of recording the forum, as they own the process. If they don't have an issue with it, I'll see if we can come up with a means to do so, and then make that video available via VAF link. At any rate, I appreciate the suggestion!

I'll provide a future update as I learn more.

Cheers,

Vac
 
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Forum Briefing

For folks up at OSH, we are conducting a forum on ONSPEED maneuvering (i.e., energy management and flying AOA) at 2:30PM on Friday, 28 July at Forum Stage 1.

An IOS-friendly PDF of the briefing can be downloaded here: https://drive.google.com/file/d/0B8EIT6g2n8o_ZmRZZzlISklQamM/view?usp=sharing. The video demonstrations are linked at will work if data or wifi is available on an iPhone or iPad.

A full PowerPoint (pptx format) with apple-compatable video can be downloaded here: https://drive.google.com/file/d/0B8EIT6g2n8o_TF9kaGc1cFlIVFE/view?usp=sharing. This is a big file (just over 1 gig) as the videos are imbedded.

We'll post a PC friendly version as time permits; and if the EAA allows, we will make a video recording of the presentation. If anyone at OSH would like to meet to discuss this project or any of the transition training resources, text or call at 850.974 four four seven two.

Fly safe,

Vac
 
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Link to Video of OSH Forum

For folks that are interested, here is a link to the Oshkosh Forum that we presented on flying ONSPEED/AoA on the back side of the drag curve: https://youtu.be/WmtnUjWSuBY.

All of the video demonstrations in the briefing are portions of previous videos that we have posted links to in this thread.

One area that I didn't touch on during the briefing was the concept of the pilot "beating the system." In an RV, it's possible for the pilot to "beat the flight control system--" literally move the mechanical flight controls so quickly the airplane does not have time to respond; and in the case of a caution/warning system like the F-4 aural AoA logic, it's possible for the G-onset rate to exceed the capability of the system to provide stall warning. Here are a couple of quick video demonstrations of accelerated stalls at G-onset rates greater than 2/second (system limit):

https://youtu.be/3avXLYp68HY

https://youtu.be/DLtamTAh-Is

Notice in the second example, the system caught up by the secondary stall.

We'll work on improving the quality and usefulness of the briefing and share lessons learned as we continue to work on this project. As always, any thoughts or critiques are welcome!

Fly safe,

Vac
 
Both NASA (TN D-6210, March, 1971) and Boeing (http://www.boeing.com/commercial/aeromagazine/aero_12/attack_story.html) have similarly concluded that AoA is not a panacea, just like the AF report mentioned.

Haven't had a chance to watch the videos, but I thought the presentation was a great discussion of AoA for calm air. We've all seen the formulae for how much to adjust airspeed in gusty air (typically half the steady state wind plus all of the gust), and that higher speed translates to a lower AoA. How much lower? That's the 800 pound gorilla in the room that nobody talks about.

Suppose I were to tell you to fly the same approach speed in gusty air that you fly in calm air. I would rightly get shouted down. But suppose I told you to fly the same AoA in gusty air as in calm air -- everybody would smile and agree. But the calm air AoA is only achievable on approach at the calm air approach speed.

So that's the problem with AoA for light planes -- how do you compensate AoA for reported winds and gusts?

Stall warning? Yes. Approach aid? No.

And just as you don't chase airspeed on approach, you don't chase AoA.

Folks, the emperor has no clothes. AoA for light aircraft is a fad, interesting for calm air approaches, but only for calm air. And yes, I've got 100 hours in my RV-9A with AoA installed.
 
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Hi Ed!

Thanks for the post!

I've reviewed all of the literature that you mention, and the NASA conclusion was, in fact, appropriate at the time that it was written as is the USAF quote I use in the briefing. I believe that current technology is well past what was available at the time of the NASA study (and NASA pointed out in a more recent study that there is a dearth of CURRENT research on the topic). I think portions of the USAF quote I used in the briefing are still applicable. I fly a Boeing product at work (777) and am familiar with the Boeing position regarding AoA.

There are two areas where AoA systems shine: one is during maximum-performance maneuvering during flight and the other is during pattern operations. The AoA maneuvering rules of thumb that we have included in the briefing encapsulate the capability and limitation of current technology. What we advocate is that when AoA is stabilized and properly displayed to the pilot visually, graphically, etc. it can be used as a control indication for fine-tuning pitch inputs when maneuvering ONSPEED.

This conclusion differs somewhat from that reached during the earlier NASA experiment. The basis for this is prior military experience with similar systems and data gathered during a series of maximum performance handling tests as well extensive testing in the pattern in an RV-type.

It's very important that the system provide accurate AoA information and do so in a timely and correct manner capable of performing at nominal G onset rates and gust loads. The system we have designed to provide the aural AoA positive feed-back in the video examples provides full functionality to G onset rates up to 2 per second, which provides gust capability as well as aligning with an appropriate control input rate for the flight control system. Use of ONSPEED approach and landing also allows use of a "decoupled" control (USN) technique. This is illustrated in the normal pattern example video. In this case, pitch controls tone (AoA), power controls glide path and bank angle controls ground track--whether the pilot thinks of it in those terms or not.

When operating in the pattern, it is important to fully understand how to apply slightly fast, ONSPEED and slightly slow corrections to compensate for pattern conditions. It's also important to understand AoA/IAS characteristics for your airplane, and always apply a "trust by verify" decision matrix when considering any displayed information. After extensive flight test and data reduction, I am perfectly comfortable using the system in our test airplane as a primary reference in lieu of IAS for pattern operations, even in our low-inertia RV-types. The ability to properly manage energy in the traffic pattern greatly improves consistency during landing ops.

It is possible to manage energy precisely with IAS during approach and landing if extensive testing is conducted to allow proper application for all weight, G load and density altitude conditions, and make this information readily available to the pilot--which is exactly what the Vref tables in the Boeing allow for. In our little airplanes, flying precise AoA is the easiest way to mimic that performance without extensive flight test, data reduction, documentation and conformity.

I'd encourage you to watch all of the videos posted, and am happy to correspond. I fully understand the "green eggs and ham effect," i.e., at first-glance, there may be some skepticism; however I encourage folks to try it. This is based on my experience as a CFI (Part 61/141), USAF instructor (including aircraft handling SME/weapons school instructor/training program development/operational test pilot) and airline flying. I've tried to dovetail all of this experience to pick what has proven to be effective in communities other than GA, that, if properly applied to GA might help improve the baseline pilot handling skill set--whether that's high-quality free training resources or technology like a positive feed-back aural AoA cue.

If we fail to look at the way we train or leverage advancing technology, then mishap rates will stay parked right where they are--commensurate with resources that we, as a community, are willing to allocate.

As I state in the brief, AoA isn't the cure for cancer--but properly understood and applied it can go a long way to helping pilots more effectively maneuver their airplanes while optimizing performance and avoiding aerodynamic limits.

Bottom Line: As an energy management tool, AoA in addition to IAS and G is absolutely priceless in any airplane. The ability to manipulate thrust and lift vectors, while using a combination of pitch and power to control AoA/Airspeed/G allows you to effectively maneuver any airplane whether it's an F-15, Boeing 777 or RV-4. I don't engage in the airspeed vs AoA debate simply because it should not be a debate. Properly instrumented, understood and applied they are entirely complimentary concepts.

Sincerely,

Vac
 
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I just want to chime in here to say I've been using AOA on speed for a few months now..
I really like the fact that I don't have to constantly monitor my airspeed in the pattern like I use to and it is so easy to use, without even thinking about it if I hear the slow tone I relax the back pressure and get back to on speed .
If a 66 year old can build and use I am sure you young fellas out there would find it useful.
Just curious how many are using this system? Any rv7A flyers like myself and if so what are the numbers your using ?
Another great tool for safer flying !!

Cal
 
Thanks, Vac, for the great answer. However, I missed your answer on how to adjust approach AoA based on reported winds and gusts. And different vendors have different kinds of proprietary "normalized" AoA, so learning what works on one plane wouldn't necessarily work on another. Airspeed, on the other hand, is pretty close to universal.

Certainly the three element AoA displays would not have the resolution to adjust AoA for gusts (if you knew how to do it), and it would seem that only a needle with markings would give that kind of resolution.

Appreciate your comments about discussion, not argument, and I think we've seen lots of folks get carried away. I chose my tone to get people's attention forcefully, and I hope I didn't get carried away, either.

Now to go watch the videos.

Best,

Ed
 
Slightly Fast

Hi Ed!

Sorry I wasn't more clear, but as you point out, exact techniques are a matter of how the AoA system is calibrated and displayed to the pilot.

Typically, when flying AoA there isn't a wind additive; so you simply fly ONSPEED. If you are concerned about gusts, a Vref + 5 with half the gust up to a maximum additive of 10 is achieved by flying a slightly fast approach. When calibrating AoA, it's practical to bias ONSPEED; so if you aren't comfortable with the energy at Vref, you can simply bias ONSPEED to Vref + 5 if you'd like to carry extra energy as your baseline. Also recall, at low airspeeds, the IAS system becomes LESS precise, where an AoA system becomes MORE precise as AoA increases. If you are used to flying Boeing products, you can think of flying ONSPEED annalogous to having the auto throttles engaged--nailing an AoA allows you to precisely control your energy in a similar manner and negates the need for wind math.

With an "old fashioned" military style indicator, a doughnut plus up chevron is a slightly fast indication. If the manufacturer provides data (or you flight test), it's possible to figure out what "slightly fast" looks like on any display. Whether that display is ergonomic or useful to you during approach depends...that's why we came up with an alternative that lets you simply listen to AoA with good precision. If your system has some sort of progressive stall warning, it MAY be adapted allow you to hear ONSPEED or other useful AoA.

If the AoA system is calibrated properly, you can't land faster than ONSPEED (you simply have too much energy); so under bumpy conditions you fly a slightly fast pattern and slow to ONSPEED during the landing transition. Actual touchdown will still generally occur slightly slow (wheel or tail-low wheel landing if conventional gear or nosewheel airplane) unless you force the airplane on to the ground with more energy. A typical pattern will have some momentary deviations from ONSPEED, unless A) it's relatively smooth; and B) the pilot is having a good day :)

One other point to ponder is the amount of energy you currently carry in the pattern based on how your airspeed system is calibrated and the technique or procedures you apply to calculate Vref (plus any additive). Some folks find that when they transition to AoA, it initially seems too slow; but that perception is largely a result of previously carrying too much energy in the pattern.

This entire process is quite easy using the old F-4 aural logic, which is why we dusted it off and installed it in our airplanes. It's not as simple with other AoA displays; but a good technique with ANY AoA system is to cross-reference airspeed during use--it's just one more item in the cross-check.

Unfortunately, every RV is a little bit different. All of them require some flight test to get things dialed in.

Forgive the long answers; and I'm quite glad that you brought this topic up, since it is a great discussion point!

Sincerely,

Vac
 
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2018 EAA Chairman?s Innovation Award Winner!!

Vac, Cecil, and Chris won this year?s $25K check with this AOA aural tone generator...well done!
 
Degrees AOA?

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.
 
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