AOA Indication in >1G Turn

[lr172]

The other day I overshoot my final turn due to a stiff crosswind and I banked more than normal to compensate (didn't check, but probably around 45* or less). I don't believe I loaded up any G's, as my decent increased and I added power (My approaches are done at 85 MPH until short final). I had no negative effects or outcome. However, it got me thinking and researching to be sure I learn from this and stay safe.

It seems that bank angle in itself isn't a factor, it is the adding of G's through up elevator that causes the AOA to increase and thereby the stall speed increase. I have a D100 with an AOA indicator and my question is, if I am in a bank and near the stall point for my current configuration, will I get an AOA warning similar to when I stall level. I assume this is the case, but wasn't sure and looking for confirmation from those more experienced in this area.

Dynon recommends doing 4 stall maneuvers for AOA calibration (power-off/Clean & dirty + accelerated/Clean & dirty). I only did the power-off dirty calibration, as I didn't want the alarm going off too early in landing configuration. I am guessing they recommend this because the AOA at stall is less or more in the different configurations. Any guidance in this area? I am now thinking that I want a broader range of warning to be sure that I get a warning for the situation outlined above.

Thanks,

Larry

[ChiefPilot]

Yes, absolutely. AoA cares not about bank or pitch attitude, it only cares about AoA which is directly related to how much the wing is being asked to lift. If it's being asked to lift twice the weight of the aircraft (i.e. 2G) whether banked, wings level, or inverted, the wing will experience a higher AoA which will be reflected on the instrument.

The actual AoA will vary slightly with configuration (i.e. flaps up/down) and Dynon's method will produce something of an average. I'd recommend doing the sets they suggest; it worked extremely well on my D10A.

[dynonsupport]

I've been in an RV with a Dynon AoA system that was alerting on high AoA.

The plane was pointed straight down, was doing about 100 knots indicated, and was stalled.

It's true AoA. It doesn't care about bank, pitch, or airspeed, just the angle of airflow over the wing.

[RKellogg]

Just to clarify, a coordinated LEVEL turn is not a 1g maneuver. At any bank angle the load factor increases, proportional to the inverse of the cosine of the bank angle . Recall from primary training that a 60 degree bank turn creates a 2g load factor and a stall speed of 1.4 times the 1g stall speed. The beauty of AOA indicators is that they accurately report the approach of wing stall at any load factor and bank angle.

With increasing bank angle it IS necessary to add up elevator to maintain a level turn.

Hope this doesn't sound "preachy". Easier to read here:

https://en.wikipedia.org/wiki/Load_factor_(aeronautics)

- Roger

[lr172]

Originally Posted by dynonsupport

I've been in an RV with a Dynon AoA system that was alerting on high AoA.

The plane was pointed straight down, was doing about 100 knots indicated, and was stalled.

It's true AoA. It doesn't care about bank, pitch, or airspeed, just the angle of airflow over the wing.

Would you also recommend that I do the full calibration for the best alerting? Does it average the different AOA's or always provide the most conservative warning? I thought I read that it was the latter.

Larry

[lr172]

Originally Posted by RKellogg

Just to clarify, a coordinated LEVEL turn is not a 1g maneuver. At any bank angle the load factor increases, proportional to the inverse of the cosine of the bank angle . Recall from primary training that a 60 degree bank turn creates a 2g load factor and a stall speed of 1.4 times the 1g stall speed. The beauty of AOA indicators is that they accurately report the approach of wing stall at any load factor and bank angle.

With increasing bank angle it IS necessary to add up elevator to maintain a level turn.

Hope this doesn't sound "preachy". Easier to read here:

https://en.wikipedia.org/wiki/Load_factor_(aeronautics)

- Roger

Sounds more educational than preachy. I understood that I would pull G's to stay level in the turn, but if I don't pull back and let the nose fall, is it true the G loading is closer to 1 and risk of stall lower or is that a misunderstanding on my behalf?

Larry

[rv7charlie]

The way I understand it, if you don't require the wing to maintain altitude (descending turn), then you're no longer requiring the wing to counteract gravity, so you can dedicate that lift to turning. Go knife-edge, if you like, pull 1 g & you'll stall at the same speed. But you'll get a rather quick ride down. Going down doesn't have to mean that you've stalled.

[sblack]

The lowest stall aoa happens with full flap. If you calibrate your system at full flap you will always be conservative.

[woodmanrog]

I was taught by a fighter pilot to always "turn the plane into a bullet " when in the landing pattern. Airplanes won't stall if the wings are not loaded. Great advice.

[BobTurner]

Originally Posted by rv7charlie

The way I understand it, if you don't require the wing to maintain altitude (descending turn), then you're no longer requiring the wing to counteract gravity,.

It's not just not maintain altitude; if you don't want to increase the wing loading (and AOA) you have to allow the airplane to accelerate downward (e.g., ever increasing rate of descent). At least until the vertical component of drag plus whatever lift the wing provides (some part of 1 g?) balances out gravity.