I suppose airplanes differ--but for my airplane, the alpha angle is consistent, flaps up or down--I've tested it in all flap configurations, but I initially calibrated it clean, flaps up.

Cary

The alpha angle is always repeatable. The question is what angle do you set. I chose to set the stall angle. If you set it per the instructions the stall will happen somewhere in the red area. It's a lot easier to read the instrument if it always stalls at a prominent, easily seen point on the instrument.

This is my second flight with it and Im not trusting it much.
Im finding out that the amount of power changes the number of lights on for the stall.
I need to do more testing and get used to it.

So far I trust more seat of the pants than the AoA, but probably I will start getting to trust it.

motoadve wrote:This is my second flight with it and Im not trusting it much.
Im finding out that the amount of power changes the number of lights on for the stall.
I need to do more testing and get used to it.

So far I trust more seat of the pants than the AoA, but probably I will start getting to trust it.

Sounds like to me your becoming a real pilot... Nice one!!

Now with about 100hrs with AOA.
This is what I like.
For climb is great just 4 yellow lights all the time no matter temp, or how heavy or how high Im , I have best climb.
Windy landings, 2 lights , no float no bounce . I used to float all the time in gusty winds doing nasty landings.
yesterday was my first windy day attempt and worked very very nice.

Short field. I look at it far away on final but then when I get closer I stop looking at it and just fly it.

I installed it in a 1959 Cessna 180. Was installed in the inspection port just inside the right wing strut.

I never could get it to calibrate after many attempts. Sometimes with just me flying and once with a CFI flying left seat.

I'm removing it. The place that installed it said they'll give me my money back. We'll see.

It may need to be installed farther from the prop. Not sure. I just don't have the inclination to keep trying to calibrate it.

RR

motoadve wrote:Im finding out that the amount of power changes the number of lights on for the stall.

That's kinda what changing power does to the stall...

Gump

FYI-Plane and Pilot Dec issue just out has a short write up on AOAs...
Kind of an overview plus news some of the high end displays will incorporate readouts as part of the display.

Lc

RocketRick wrote:I installed it in a 1959 Cessna 180. Was installed in the inspection port just inside the right wing strut.

I never could get it to calibrate after many attempts. Sometimes with just me flying and once with a CFI flying left seat.

I'm removing it. The place that installed it said they'll give me my money back. We'll see.

It may need to be installed farther from the prop. Not sure. I just don't have the inclination to keep trying to calibrate it.

RR

I have the LRI -not electric light version. I use it quite often and wouldn't be without it. I've used it for the last 8 years or so and it works . try this http://www.liftreserve.com/

Im liking my AoA more every day.
Initially was having some doubts, it takes time getting used to.

I have enough time flying with mine now that I'm absolutely sold on it. Mine is the mechanical analog version, mounted on the top of the panel, so it's easy to see with peripheral vision as I watch the landing area ahead. As I've mentioned, its needle is narrow enough that it's not easy to see in the dark, but otherwise, it's pretty useful, even to someone like me who has enough experience to "feel" what the airplane is doing.

Not sure why RR is having trouble calibrating it. Mine's installed in the same place, the inspection port inboard from the right strut (P172D). As it came from Alpha, it couldn't be calibrated, because it needed to be tilted farther back than the approximate 50 degree angle described in the instructions. A little filing of the opening allowed it to be tilted back farther, and calibration was exactly as described in the instructions.

Cary

More good news for folks who want to install an AOA and are worried about whether or not it's a logbook sign off or requires a field approval. Here's a post from another forum and a copy of a letter FAA that settles this. Sorry for the long post but it will tell the story of how we came to this point. These are the folks that got me my AOA because they knew how I would set it up and where I fly.


Good morning to all.

When a federal agency gets it right and responds promptly, we all need to pause, to recognize, and to applaud.

I would like to nominate Peter Rouse and David Sizoo of FAA-SAD (the Small Aircraft Directorate) for a special award with accompanying national publicity from AOPA Air Safety Institute. And from the B2OSH group. And from the ABS. I am totally serious. I have no idea what to call it, but “FAA HERO OF 2011” comes to mind. These are two men of courage and integrity with foresight and clarity of vision:

Peter Rouse is a FAA Aerospace Engineer
Policy and Regulation Branch, ACE-111
Small Airplane Directorate - Federal Aviation Administration
Pete flies a Baron and has long been a participant in the B2OSH mass arrival at Oshkosh. He's a wonderful quiet guy so he never mentioned what he does for a living. We have a star among us!

David Sizoo is a FAA Flight Test Pilot
Aircraft Certification Service, ACE-112
Small Airplane Directorate - Federal Aviation Administration
Dave came off the F35 Joint Strike Fighter Flight Test program and now flies off new certifications for the FAA-SAD.

I flew these two men in my Alpha System AoA-equipped King Air 90 a few weeks ago and they saw with their own eyes how reliable and repeatable the Alpha System AoA sensor/display is. We discussed the non-intrusive installation with no new holes cut in the pressure vessel of the King Air. They heard that I have no financial interest in any AoA product or company. A week later, they installed an AoA Enhanced Legacy system in a Kansas City FBO rental aircraft that the FAA-SAD staffers use for recurrent training.

On Friday Dec 16 they delivered to Mark Korin at Alpha Systems AoA everything they told me they’d try to do ... and more! Mark sent me their FAA-SAD letter of clarification, which is attached.
And posted at http://www.ballyshannon.com/aoaminormod.html

Their letter will save a lot of lives; it has been reviewed at the senior FAA-SAD level AND at the FSDO management level. This FAA-SAD clarification should eliminate almost all field objections to installing a simple non-intrusive AoA system on almost all small aircraft.

A year or so ago, at Tom Rosen's and my request, starting with Bill Hatfield last summer in contact with the Chicago ACO (they said: "this simple supplementary device doesn't need an STC ..."), the FAA Small Aircraft Directorate just issued an extraordinary letter. Basically, they ratified everything that we have been saying, specifically including the fact that, in MOST light aircraft, the Alpha System AoA that Butt, Sasser, Friedman, Stovall, Earle, Niemi, Paysse, etc. fly with ... may quite properly be installed as a simple minor alteration. They basically say "there are very real safety benefits from such devices; go for it,".

I have never seen such a letter from the FAA, but the seatbelt refits may have been similarly handled. While the letter happened to be mailed to AlphaSystems, their intent w/r/t similar non-intrusive systems is very clear.

Hugely important news, an example of truly great open minded engineers using logic and courage, it represents the very best of the FAA.

The Feds have ten major initiatives. The first two are
Stop the stall/spins in the landing pattern, and
Stop the departure stall/spins.

Alpha sensors/displays can help with both. Even great aviators with good airmanship skills can benefit; the Alpha devices do not lie. But they MUST be used along with the primary reference: Indicated Airspeed, and ... Airspeed must remain as the primary reference, because that is how the aircraft was certificated. I will not be at all surprised to read, within a year, that all new certifications will require Alpha sensors. That certification requirement will come from the FAA-SAD. From the same agency that helped us. I hope that happens. It will cost next to nothing to include Alpha sensors as an airplane is being assembled.

Remember, we don’t get any better performance out of an AoA-equipped aircraft; an AoA will simply TELL US MORE, and VERY PRECISELY, about how much stall margin we have.

Tom Rosen and I are simply in awe of the response we got. Far more that we were hoping for, FAA-SAD fully ratified our efforts over the last year and a half. They did it in only six months, and the clarification letter was fully vetted by senior FAA-SAD and the FSDO leadership.

How about that? Tom Rosen and I have four dead pals who are surely looking down from Heaven at these men today. I am quite certain that they are very pleased.

A special thanks to Bruce Landsberg at the AOPA Air Safety Instutute: Finally! ... I am truly honored to know this man. His writings and teachings have been a voice in the wilderness for far too long. Two decades, at least, by my memory. On Alpha sensors, Bruce’s has occasionally been a lonely voice, but he has been right all along. Oh, so right he has been!

To our AoA Flight Test pilots, who proved that this one system really works: Al Aitken (Al flight-tested the USMC Hornets at NAS PXT and wrote our AoA test flight plan), Will Moore, Jack Stovall, Earle Thompson, Mary Jane and Bob Butt, Joe Sasser:...Tom Rosen and I are humbly grateful for your time and effort. Thank you every one.

To our early installing A&Ps: Richard Kiser, Kyle London, Steve Bradley at Classic Aviation in KSHD. You dug through the existing, somewhat unclear, guidance and you figured out that installing a simple non-intrusive AoA was perfectly OK. Bravo!

Sometimes, the planets just get themselves aligned. Today is such a day.

Let us, truly, give praise.
Fred



Here's the link to the FAA letter.

https://docs.google.com/open?id=0Bwh7FTrOVQuVYWIyYTU2Y2ItODhiMy00Y2JlLThjMDUtZmU2OTE3MjdiZTA0

I agree with a comment I read.
Will save more lives than the parachute.

I have the Alpha AoA and love it.
I look at it
Climbing, doing tight patterns,turning to base, landing, and even more important when landing with wind.(has been amazingly helpfull in these conditions.)
Ironically the time I dont look at it much is when short field landings, maybe once on long final, but then no more, and prefer not to be distracted and go by feel.
Maybe need to get used to it more.

Vick wrote:To revive this topic once more, I swung by the Alpha Systems booth while at OshKosh and spoke with the owner for a while. I asked him what he thought of the contention that his product is not a "true" AoA system and challenged the utility of AoA in light GA aircraft. He had a strong working knowledge of AoA system design and factors in measuring AoA, to include accounting for asymmetric lift/airflow and prop wash. He produced the original study commissioned by the Air Force (in the 70s I think) that assessed the viability of a pressure-differential AoA system and further pointed out that the AoA system on the F-22 is pressure-differential based.

No doubt there was some salemanship at work but I came away impressed with his level of knowledge and confident that he wasn't just selling snake oil. It's well established that you don't "need" an AoA system on a light GA plane, but then you don't "need" a GPS either - these systems just provide higher fidelity information in a convenient format. If nothing else I would say that the charge that this isn't a "real" AoA system is unfounded. I can't comment further because I haven't had the opportunity to fly behind one of these systems, but I'm certainly open to giving it a fair try if the opportunity arises.

Hey Vick - It's Cabi~. I actually know the owner of Alpha Systems AOA personally. He even put a photo of me on his website! (I'm famous) I was the one who told him to change the name of the unit(s) and company to reflect that it is ACTUALLY an AOA system because he used to call it a "Reserve Lift Indicator".

Mark's AOA system is a "true" aoa system using differential pressure in order to measure the angle of attack of the wing. Someone posted that it was a pitot-static system, but it is NOT a pitot static system. The AOA probe actually is mounted at approx 70deg angle and there are two ports (upper & lower) which can differentiate the angle of the wing relative to the relative wind - by using differential pressure between the two ports. This is a very good system, good enough that the FAA is allowing his system to be used/installed into certified aircraft without any FAA/PMA certifications - with the caveat that the aoa system does NOT cut into the aircraft's pitot static system or any flight control system (meaning flaps). As long as it is a self contained unit it only requires an A&P logbook entry as a "minor change" (no Fm337 req'd).

If Mark was to attach a sensor to the flaps system, this would be a modification of the flight controls and would require the FAA's very cost prohibitive certification process which would trickle down to the customer in the form of THOU$AND$ of dollar$. The current system actually is designed to be installed onto one of the wing underside access panel so as NOT to have to mod the wing in any way. This is one of the reasons the FAA allows Mark's aoa system to be a minor change and not a major alteration/repair. Once it is calibrated it is very accurate in measuring the aoa of the given wing it was installed upon and calibrated to.

You know me, Vick, I've been flying AOA systems for 24 yrs and I can tell you diffinitively that this is a "real" AOA system. He's even got a unit that's got Bitching-Betty in it too!

Cheers!

Semper Paratus

iPipehitter599 wrote:Mark's AOA system is a "true" aoa system using differential pressure in order to measure the angle of attack of the wing. Someone posted that it was a pitot-static system, but it is NOT a pitot static system. The AOA probe actually is mounted at approx 70deg angle and there are two ports (upper & lower) which can differentiate the angle of the wing relative to the relative wind - by using differential pressure between the two ports. This is a very good system, good enough that the FAA is allowing his system to be used/installed into certified aircraft without any FAA/PMA certifications - with the caveat that the aoa system does NOT cut into the aircraft's pitot static system or any flight control system (meaning flaps). As long as it is a self contained unit it only requires an A&P logbook entry as a "minor change" (no Fm337 req'd).

So by that definition, ANY airspeed system is in fact an "Angle of Attack Indicator", since EVERY airspeed system in fact measures ram air pressure and compares it to static pressure.

Take a close look at the pitot mast on a late model Piper Warrior....it looks remarkably like the sensor mast on one of these devices.

If you're happy with the device, good on you. I doubt these things will stop folks from screwing their airplanes into the ground, though.

MTV

I have one, it helps and I like it.
Helps when Im doing photo flights, when approaching in windy conditionds, on long final in normal runways, on climbout, to get VX or VY easily.
Also is not super accurate bullet proof device, I have been on a downdraft, going down near the threshold of the runway where my plane is based at (we have a nasty gully) and the AoA indicated I had lift.
So common sense has to be applied.

Only time ironically I dont look at it , its on short landing strips I dont even look at it or the airspeed indicator either.

My AOA indicator always tells me the same thing....

I'm being ATTACKED FROM ALL ANGLES!

Never changes...maybe it's broken.....

mtv wrote:So by that definition, ANY airspeed system is in fact an "Angle of Attack Indicator", since EVERY airspeed system in fact measures ram air pressure and compares it to static pressure.

There's not a static port on these differential pressure AOA systems, rather two ram ports at some angle to each other. If your AOA system acts like an ASI, or vise versa, then you're not doing it right. I've flown a bit in a Rans with a Dynon Skyview equipped with their optional AOA pitot tube (AOA integrated into the pitot tube, one of the two AOA ram ports is also the pitot port, but same principle as the standalone AOA systems), and they work quite well.

You can question the usefulness of having AOA information in the cockpit, but the operational principle of these devices is sound and totally different than an ASI.

NoCOpilot wrote:

mtv wrote:So by that definition, ANY airspeed system is in fact an "Angle of Attack Indicator", since EVERY airspeed system in fact measures ram air pressure and compares it to static pressure.

There's not a static port on these differential pressure AOA systems, rather two ram ports at some angle to each other. If your AOA system acts like an ASI, or vise versa, then you're not doing it right. I've flown a bit in a Rans with a Dynon Skyview equipped with their optional AOA pitot tube (AOA integrated into the pitot tube, one of the two AOA ram ports is also the pitot port, but same principle as the standalone AOA systems), and they work quite well.

You can question the usefulness of having AOA information in the cockpit, but the operational principle of these devices is sound and totally different than an ASI.

My point was, that's a very poor definition of what a REAL AOA sensor looks like. Here's an image of a more typical AOA sensor:

The Piper Warrior pitot mast is remarkably similar to what one of these general aviation systems uses as a sensor. I'll post a photo when I can get through the snowdrifts to a hangar....

MTV

iPipehitter599 wrote:Hey Vick - It's Cabi~. You know me, Vick, I've been flying AOA systems for 24 yrs and I can tell you diffinitively that this is a "real" AOA system. He's even got a unit that's got Bitching-Betty in it too!

Hey Cabi, welcome to BCP. About time you stop posting pics of plastic planes on FB and post some shots of your Cub on here.

I'm with you on AoA, kept my ass alive more than once, especially around the boat. I'm looking forward to giving the Alpha Systems product a try some time, decide for myself its value.