AOA or Stall Warning ????

I'm near completion of the wings for my 9A and the question keeps coming up should I install an AOA, lift reserve detector or stall warning device ?? Should I wait until it's flying and then determine the need......or should I not even worry about it ??? Is it really necessary and could I use the $$ elsewhere.

Any comments, suggestions would be greatly appreciated.

Henry
N918HB

hammer408 said:

I'm near completion of the wings for my 9A and the question keeps coming up should I install an AOA, lift reserve detector or stall warning device ?? Should I wait until it's flying and then determine the need......or should I not even worry about it ??? Is it really necessary and could I use the $$ elsewhere.

Any comments, suggestions would be greatly appreciated.

Henry
N918HB

Click to expand...

I would wait until you're flying to see what you need/want. I find that neither is necessary. I might like to have an AOA someday just as a toy to determine exactly where max perform speeds are, but once you've flown her once or twice, you know when you're getting slow by the feel. This bird isn't going to surprise you.

Spend your money elsewhere.

One other thing I'd chalk up to 'spend your money elsewhere' is a flap position indicator. You can literally see the flaps out of the corner of your eye. I installed one and haven't referred to it a single time.

If you don't have plans to install an auto pilot (I have a digiflight single axis running off my Garmin 196 GPS), change your plans. These things are amazing, and amazingly useful.

Brian N9612S 11 hours and counting

AOA or stall warning?

Henry,

I bought a flying 6 last fall and installed a PSS sport AOA. I flew close to 30 hours without it, and subsequently, 70 hours with it. I would most definitely do this again, and when I finish my 8 it will have the AOA. I really use it alot especially in the pattern, I have it positioned directly in front of me and get the view without concentrating on the panel. I am very satisfied with the PSS version.

Jim
RV6 flying
RV 8 wings

stall warning/aoa indicator

Henry,

I agree with Brian. I can't imagine needing or even finding one of these devices helpful in my 9A. I don't know if you have ridden in one, or have gotten a demonstration of the stall characteristics of the airplane but it is a real "NON EVENT." I'm not trying to be condesending, just trying to keep you from wasting money on something that could be better spent someplace else. I'm going to try and describe stalls in the 9A for you with no embellishment as they happen in both mine and the factory plane which I took transition training in.

Approach: Set up for minimum controllable airspeed and in level flight. Reduce power slightly and hold back on stick. At the buffet just slightly release back pressure with no noticable forward stick movement. The stall is over! If you were to do the same thing but not release backpressure on the stick the nose attitude would drop, but hardly at all and then the pressure recovery design of the Ronz Airfoil starts the plane flying again. Altitude loss will be 10-20ft. The markings on the altimeter are almost to course to measure it. Every pilot that I take up is always amazed by the way the nine does not stall.

Departure: Full throttle, prop forward, nothing but sky in the windshield. The attitude is so uncomfortable that this could never be achieved in normal flight. As the airspeed drops below 60 all of the attention for me is on the ball being centered. The mind starts to prepare itself for a violent drop. Here it is, the buffet. Gently releasing pressure, but again no forward stick movement and the buffet is gone. The plane continues climbing at the extreme attitude it was at the instant of the stall. Not only no altitude lost, but no noticable change in the climb rate.

Turning Departure: See above, but you are turning.

The only flight regime that could possibly be a problem would be a downwind to base, or a base to final turn with to steep of a bank angle. But once you start to fly yours you will see that the plane is hard enough to slow down to flap speed, and with flaps applied or even with none turning base at 80mph and final 80 or slightly less you are so far above stall speed that a stall is not likely. You really have to screw up to stall this airplane, and then it takes care of you.

My two cents,
Bryan 9A flying

To AOA or not to AOA

I flew my RV-6 a couple hundred hours before installing a LRI and have since added another 450 hours. The fact that the RV-9 has a more benign stall than the -6 really has nothing to do with this discussion. Once a pilot realizes how useless the airspeed indicator is when flying close to stall under varying load and density conditions, he will begin to investigate the installation of an AOA.

Hundreds of RVs are being flown safely without an AOA indicator, and probably a bunch more where the pilot really doesn't have a very good idea what the actual stall speed is at any given loading. But, if a pilot has an interest in maximum performance takeoffs and landings (short fields with limited approaches or carrying a heavy load at high density altitude) the AOA can pay huge dividends. If the anticipated mission profile includes only long, paved runways with a light load, then an airspeed indicator is probably a luxury.

The LRI is my primary instrument for takeoffs and landings, and my plane has two airspeed indicators. I'm an unabashed convert to AOA and consider it a valuable tenent in my panel.

Sam Buchanan
http://thervjournal.com/liftreserve.htm

AOA or stall warning

Bryan,

I don't feel like you are being condescending at all. I have flown though for close to 30 years and have watched the accident statistics through the years. One of the most common fatal accidents is stalling in the pattern. You can get so "into" enjoying the flying and just get a little slow while turning downwind to base or base to final or kick in a little cross control to compensate for misalignment and when the stall occurs find that there is not enough altitude to compensate. I know, watch the speeds, but the airspeed indicator may not be accurate at the lower speeds . The AOA is just one more thing to help in keeping things under control. Also, I have found it to be very useful with slow flight (flying in crowded airspace following non RVs in the pattern especially). I use mine every flight and would not have another plane without one. I have found it very valuable. I think since Henry asked, he should hear from both sides on this topic. I don't consider it a waste of $ at all, I think it is a very valuable instrument and would definitly recommend one. Just my 2 cents.


Jim

aoa/stall warning

Jim and Sam have good arguments for an AOA. Boy, I guess there are just so many decisions while building our airplanes and lots of us offering ideas to muddle it up even more. Even though I can't imagine getting into a situation where I need one of these, I kind of want one now too. I guess you can't be to safe.

Bryan

People like them

I've yet to meet a pilot that has flown with an AOA that says it is not useful. Some go as far as saying it should be mandatory. Not many things we add into our airplanes are so strongly recommended by people that have used them.

I traded my AOA for a stall warner

I originally bought a $900 AOA, but then realized that a simple stall warning vane is basically just a go/no-go AOA, which was all I really needed. I sent it back and spent $60 on the "Reddish Stall Warner".

An AOA will help you make very precise landings. A stall warning will merely keep you out of trouble. Not having an infinate supply of money, I decided that I needed an autopilot more than I needed to make perfect landings every time (although I'm sure my wife wishes I'd kept the AOA!).

By the way, others have mentioned that it's impossible to get an RV into a stall without first noticing the high angle. That's only true when you first start flying it. The accident records will tell you that the majority of RV fatalities are from stall/spins -- same as any other plane.