Bender wrote: In a GA airplane, especially a STOL aircraft, I really don't see the need for an AOA indicator as long as you have a dependable airspeed indicator.

If you like to have your eyes inside the plane watching the ASI, and doing math (not just weight, wind gusts, sometimes DA, power on vs. power off, maybe even CG location) while also landing the plane, then yes you probably wont benefit from having an AoA indicator or similar device.

I wasn't convinced initially, but since flying with one I really think they are a great safety feature. They would certainly prevent some accidents if they were standard equipment.

To each their own. I've got a couple thousand hours in jets with AOA indicators and wouldn't want to land on a carrier without one. However, if you know the corresponding airspeed to "on-speed" AOA and trim hands off you should still have the ability to bias 99% of your scan outside. Also, I hope simple math such as adding or subtracting 1mph/200lbs to an established baseline isn't too complicated for an aviator. DA shouldn't have much effect on "Indicated" on-speed AOA.

Bender wrote:DA shouldn't have much effect

Not at low level. If you were up high enough it could, depending on what kind of plane you're in I suppose.
I did 17 years of math lessons all said and done. I still don't do math for fun

I've been reading these discussions about AOA indicators for years. The discussions usually provide more heat than light. This one is better than most. Some feel that the seat of one's pants is always better than an instrument. Some feel that the ASI is quite sufficient thank you. Others that it adds a level of utility so why not. There are some who are convinced that only a sissy would have one in an airplane. I dunno.

I've never flown with one in my whole wide life. I somehow doubt that much will change with an AOA indicator in an aircraft with light wing loading and gusty conditions near the ground. I suppose it might give you an earlier "go around" signal than you might get in those conditions with just a stall horn; if there's room to go around. I think the AOA is going to be warbling at you in any kind of wind gradient on short final. So you go to 1.4 VSO and be careful with those brakes eh? So if your power on stall with just a skosh of power is 39K and you add 3.9K to that you got almost 43K right? How big a skosh was that anyway? Let me check the AIM for the definition of skosh......Does your ASI work at 43K?

But:

I'm going to install one anyway. Probably this one here that we're talking about when the time comes. I don't think the ASI in a CH701 is much good at any speed. The manufacturer of this unit told me to mount it out on the wingtip as far forward and inboard on the tip as possible. Sounds right to me with that slat sticking out there. It's just another tool in the box you know? I like tools.

I'm the inventor of the CYA-100 angle of attack system, and was introduced to this forum by one of your members who is also a Mooney driver (and who ordered one of my units).
The entire Mooney thing started when another of their members ordered one of my units, installed it, and plugged it on their forum. Then the forum asked if they could get a group discount, and I agreed to a 10% discount if they could guarantee 10 orders. The response has been overwhelming, and I'm also honoring the same discount here for orders placed before the end of this month.
I know that different forums (forii, forae?) have different rules for discussions of commercial products, so don't hesitate to slap me if I'm overstepping the bounds here!
My website is: http://www.ackemma.com/index.html
Other than perusing the site, the best piece of information is the installation manual at the link on the top of the "TECH" page, and I'm always open to suggestions.
The entire subject of angle of attack displays is very personal, so I won't go into that here. However, my discussions with the FAA to get "blanket installation authority" has been interesting. I've been told that AoA is a very high priority with them, and that I can expect a response from them by mid-February (and it's a Federal agency, so I'm doing whatever I can to avoid turning blue while holding my breath).
In any case, until that's fixed, make sure your IA is OK with the install. My own opinion is that ANY AoA indicator is better than none. While my CYA-100 is a "true" AoA system and uses a vane, other systems derive AoA with differential pressure measurement, and they work well too.
Most of them are derived from a very old article about converting an airspeed indicator to display angle of attack, so the idea has been around for decades.
For those who have already placed orders, many thanks! Shipment will be in 2-3 weeks. For those who haven't, please consider it. And not just one of mine, but ANY AoA indicator. I truly believe these things can, and will, save lives.
Any and all comments and questions entertained!

Rip

Bumper, you need more quality stick time not more gadgets IMHO. Put avgas in the plane and fly the crap out of it low and slow, at Minimum airspeeds. Get comfortable on the bottom end of the curve. No gadget is going to help basic feel for the wing and airmanship.

rq3 wrote:it's a Federal agency, so I'm doing whatever I can to avoid turning blue while holding my breath

Good luck. I've moved my STC/PMA work to a distant FSDO for the same reason. They just can't handle the concept of commercial development in my local office that doesn't involve hiring a single available DER in the area who (surprise surprise) used to work in the local office. And also good for you for rejecting the RTCA DO-160 silliness. Regulating standards should be public, not hidden behind a single vendor with a $400-per-license crack habit.

Battson, no offense, but I'm not sure you understand the concept of density altitude. Density altitude and IAS are both a measure of the potential aerodynamic energy in an air mass. If you have a 2,000 ft DA at an airport at sea level and the same 2000 ft DA at an airport at 10,000 ft elevation your aircraft is going to fly exactly the same at either airport. As for stall speed, it doesn't matter what the DA is, your aircraft for any given configuration (weight and control settings constant) will stall at the same "INDICATED" airspeed regardless of DA.

Flyboy_AK wrote:Bumper, you need more quality stick time not more gadgets IMHO. Put avgas in the plane and fly the crap out of it low and slow, at Minimum airspeeds. Get comfortable on the bottom end of the curve. No gadget is going to help basic feel for the wing and airmanship.

Flyboy,

No offense, but that's a bit like saying real pilots don't need flight instruments - - just fly by the seat of your pants - feel the wings. Do you *really need* an air speed indicator? I've flown without one a couple of times . . . not a big deal, you can feel the controls and glean from your other senses what a safe approach speed is. That doesn't mean I think it's a good idea to fly without an ASI - - it's very helpful to have an accurate idea how how fast you are moving through the air. Not having a working ASI, means most pilots will carry a bit more speed than needed, just to pad their safety margin a bit - - no big deal with lots of runway, but in the bush?

Same might be said for an AOA. I can see it being a useful tool in it's own right, Kind of like a TC is to a Horizon when instrument flying, there's some overlap. And, the AOA tells you something the ASI does not. Does than mean you cannot get the AOA's info in other ways? Nope. But the AOA, like the ASI, will present its information is an expedient and useful way for the pilot's convenience. I've got about 3.5K hours in small GA and glider, why would I want to add an AOA now? I've come around some on this issue, like you, I used to think it was fluff. Now I'm considering that I may have been wrong and that an AOA looks to be a useful tool. I'm buying one to evaluate for my Husky. Then I'll decide if I want to add them to my other aircraft.

BTW, I'm absolutely sure you have no clue as to how good a stick I am, how often I fly, or how much of that is worm burning down low. Suggesting I should spend my money on avgas and fly more is ludicrous on it's face. I'm retired, sort of, so can play with my airplanes whenever I like and as much as I wish. I'm fortunate to have enough of my allowance squirreled away that buying an AOA will in no way impact my ability to purchase avgas.

bumper

Bender wrote:Battson, no offense, but I'm not sure you understand the concept of density altitude. .

Yeah that's clear to me - and the easiest way to get a higher DA at landing is land at high elevation airport... but no, the finer points of DA aren't lost on me. Four years of university specialising in fluid dynamics makes to concept quite 'understandable'.

The argument I was originally making is dead simple:
>Stall airspeed is affected by more things than I want to list, from contamination of the aerofoil, to CG location, to bank angle / load factor.
>Stall angle of attack remains unchanged under practically all flight conditions for our purposes.

Why on earth would you want to rely on airspeed - which is just a flight instrument like AoA?
Why not use the right instrument for the purpose?? Especially when it's so affordable!

Bumper -

Pay no attention to the peanut gallery.

I applaud your desire to further understand the flight envelope of your aircraft, and I know that an AOA indicator is an instrument that can make that so.

Looking forward to your report after the install.........................Rob

I really appreciate my AOA indicator and what information it provides for me.

Since I know that my plane will stall at different angles depending on my flap settings, I reference specific points on the gauge when flying at zero, 10, 20, 30, and 40 degrees of flaps. To me, this is easier than airspeed references, especially when considering that my plane can fly across a useful load spectrum of 1400 lbs, and it flies totally differently at gross when compared to just me and some fuel. Seat-of-the-pants flying is one thing for 135 operator or other professional guys who fly heavy all the time and 700+ hours a year. I don't care what happens in my dreams, I will never be a Paul Claus; period. Does Paul need an AOA indicator? No. But I am not that guy. Are there guys on this site as good as Paul who wouldn't need AOA feedback? Sure. Some people are just born with skills and have abilities that rise above the masses. Bobby Breeden comes to mind. Bobby does not need an AOA indicator. But for me, that AOA indicator makes me a better/safer pilot.

I liked the recent article on the subject of approaches where the author uses a reference angle of the wing against the horizon to help essentially fly a consistent and relatively high angle of attack. However, this reference angle means nothing when power settings are not held constant. With an AOA indicator, consistent angles of attack can be flown at various power settings including at various weights and weight configurations.

I do not think you will find the answers on this forum as to whether you will benefit from an AOA indicator. There are obviously opinions on both sides. For those of you who are curious but have never flown behind one, I recommend you get a demo flight from someone who has one. I am happy to demo mine to anyone. If you find it isn't useful, you got a free flight and you also saved several hundreds of dollars from not having to buy one. But to be honest, most people who have flown with me and have seen the AOA indicator in action tell me they want one.

Most slow BC planes when real slow do not have a dependable or accurate ASI! I know I sure don't depend on one! That's just me tho!

lesuther wrote:

rq3 wrote:it's a Federal agency, so I'm doing whatever I can to avoid turning blue while holding my breath

Good luck. I've moved my STC/PMA work to a distant FSDO for the same reason. They just can't handle the concept of commercial development in my local office that doesn't involve hiring a single available DER in the area who (surprise surprise) used to work in the local office. And also good for you for rejecting the RTCA DO-160 silliness. Regulating standards should be public, not hidden behind a single vendor with a $400-per-license crack habit.

A man after my own heart. I've been through the DO-160, TSO process, which was kind of odd (basically a statement that your product complies).
But that was decades ago, and I agree that a publicly viewable standard as to what the consumer is buying is the way to go, whether that consumer is private, corportate, or commercial.

I'm not dealing with my FSDO. My latest communications were with Earl Lawrence, the head of the FAA Small Aircraft Directorate. He came out of the EAA, and I'm hoping that will help to provide some sane Federal guidance when small Part 91 aircraft are the issue.

The fact that you have to "shop" for a compliant FSDO is common, and ludicrous. Once upon a time, a ferry permit was a phone call and a return FAX. Now it's FAA inspections, declarations, etc. If the local IA isn't qualified to determine airworthiness, then what's the point of the IA ticket?

If there are standards, they should apply across the board. As I've said to my local FAA inspector: "You guys work for a schizophrenic organization. You have two disparate charters. Promote aviation. Promote aviation safety. You can have 100% of one by driving the other to 0%. Your choice."

I feel for the FAA employees. They generally do the best they can given the balancing act they are forced in to (see above), and generally do it very well, with minimal support from Washington. They have to interpret the regs as best they can, with little, and very slow, guidance. Is it any wonder it's a CYA mentality?
Rip

The first time I saw a Lift Reserve Indicator, I had the same reaction--why? After all, I had a good ASI and a stall warner, and I'm a pretty good seat-of-the-pants pilot.

Then I had a long conversation with Mark Korin, the owner of Alpha Systems, who make an updated version of the LRI while at OSH. A couple months later, I made a bone-head take off from Marble, and although I survived my own stupidity (only because I'm an exceptionally skilled pilot, of course ), I thought it would never have happened had I had an AOA in the airplane. I decided to get the Alpha Systems mechanical version, but with the heated probe.

My indicator is mounted on the top of the panel, where it's easy to see with peripheral vision--I don't stare at it. There's no connection to audio, although that would be helpful in many cases, I suppose--that's available with Alpha's electronic versions. Here's a pic of my panel before I replaced the compass with a SIRS compass:

Since I often fly with varying weights, I've found it very useful for being able to land much slower with light loads vs. "book" speeds with full loads. Often we think that the difference won't be all that noticeable in a 4 seater GA airplane, but it is. It also takes all of the guess work out of pitching up at very high density altitudes, such as making a bonehead over-rotated noon take off from Marble. Consequently, I've become a bit of a proselyte for AOA indicators--several posts on this forum and on others.

Cary

Cary wrote:The first time I saw a Lift Reserve Indicator, I had the same reaction--why? After all, I had a good ASI and a stall warner, and I'm a pretty good seat-of-the-pants pilot.

Then I had a long conversation with Mark Korin, the owner of Alpha Systems, who make an updated version of the LRI while at OSH. A couple months later, I made a bone-head take off from Marble, and although I survived my own stupidity (only because I'm an exceptionally skilled pilot, of course ), I thought it would never have happened had I had an AOA in the airplane. I decided to get the Alpha Systems mechanical version, but with the heated probe.

My indicator is mounted on the top of the panel, where it's easy to see with peripheral vision--I don't stare at it. There's no connection to audio, although that would be helpful in many cases, I suppose--that's available with Alpha's electronic versions. Here's a pic of my panel before I replaced the compass with a SIRS compass:

Since I often fly with varying weights, I've found it very useful for being able to land much slower with light loads vs. "book" speeds with full loads. Often we think that the difference won't be all that noticeable in a 4 seater GA airplane, but it is. It also takes all of the guess work out of pitching up at very high density altitudes, such as making a bonehead over-rotated noon take off from Marble. Consequently, I've become a bit of a proselyte for AOA indicators--several posts on this forum and on others.

Cary

Man that's a lot of clutter what's your office desk look like

CYA-100 Shipment Update:
I have built enough units to fill orders to date BUT, the urethane potting compound I use for the display can't
be shipped in freezing conditions. My supplier thinks we have a window of opportunity this week, so I'll be
shipping later this week if all goes well.

Thanks,
Rip

Pusher wrote:You might want to read this paper from Professor David F. Rogers about determining AOA with differential pressure probes.

http://www.nar-associates.com/technical ... screen.pdf

Just gonna double check his numbers and equations...I'll get back to you in...100 years..!!!

rq3 wrote:CYA-100 Shipment Update:
I have built enough units to fill orders to date BUT, the urethane potting compound I use for the display can't
be shipped in freezing conditions. My supplier thinks we have a window of opportunity this week, so I'll be
shipping later this week if all goes well.

Thanks,
Rip

So does this mean it won't work in a freezing airplane?? I'm not the sharpest tack in the card you know!! Please xplane!

M6RV6 wrote:

rq3 wrote:CYA-100 Shipment Update:
I have built enough units to fill orders to date BUT, the urethane potting compound I use for the display can't
be shipped in freezing conditions. My supplier thinks we have a window of opportunity this week, so I'll be
shipping later this week if all goes well.

Thanks,
Rip

So does this mean it won't work in a freezing airplane?? I'm not the sharpest tack in the card you know!! Please xplane!

Think two part epoxy. The urethane is two liquids that get mixed together and then harden. Once it's hardened, the urethane is good from -72C to +200C. But the unmixed liquids don't tolerate freezing very well.
Rip