Flying a twin jet where you do steep turns without touching the rudder isn’t the bar we should be setting.
Commercial maneuvers - how much does the plane matter?
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Flying a twin jet where you do steep turns without touching the rudder isn’t the bar we should be setting.
Ed Haywood
Final Approach
I was asked to pop in and comment on spin recovery. There's a lot of aerodynamic discussion going on, some of it correct and some of it off base to varying degrees. I'm not an expert, but I do have a good bit of practical experience pushing my plane to its limits, so I'll stick to that.
First, about G-LOC. TBH it is hard to do that in a GA aircraft. I flew contests for several seasons before I got my first taste of tunnel vision. G-LOC requires both force and duration. Somewhere there is a graph, but in my experience you need to pull around 5G and hold it for about 5 seconds. That is hard to do, because when you load up G's the plane slows down. So you gotta use power and gravity to keep accelerating.
Let me describe the maneuver where I got a bit of gray to give you an idea how hard you have to work to get it. I was rolling inverted at 90mph, pulling to a vertical line down, flying straight down for a count of 2 seconds with full power, then pulling 5G to a vertical line up. I was generally well into the yellow arc during the pull.
When I experienced the vision issue, I asked a few mentors, and they all said the same thing. It's normal, grunt and flex your lower body just before pulling and you'll be fine.
First, about G-LOC. TBH it is hard to do that in a GA aircraft. I flew contests for several seasons before I got my first taste of tunnel vision. G-LOC requires both force and duration. Somewhere there is a graph, but in my experience you need to pull around 5G and hold it for about 5 seconds. That is hard to do, because when you load up G's the plane slows down. So you gotta use power and gravity to keep accelerating.
Let me describe the maneuver where I got a bit of gray to give you an idea how hard you have to work to get it. I was rolling inverted at 90mph, pulling to a vertical line down, flying straight down for a count of 2 seconds with full power, then pulling 5G to a vertical line up. I was generally well into the yellow arc during the pull.
When I experienced the vision issue, I asked a few mentors, and they all said the same thing. It's normal, grunt and flex your lower body just before pulling and you'll be fine.
Ed Haywood
Final Approach
Now about stalling in a spin recovery ... or any other time. The important thing to remember is that stalling is about AoA, not Vs. Stall speed is useful when you are near straight and level. When you get into unusual attitudes, it is not so much help. Then it is all about relative wind and AoA.
Let me give an illustration. Let's say you pull vertical up and hold it. When you are below Vs, will you stall? Nope. You can continue flying straight up until you hit zero mph.
Now let's say Vs is 54mph. When you hit 50, you push forward to level. When you hit level at 50mph, will you stall? Depends on what you do with the stick. If you keep power in and pull the stick back just enough to keep the nose on the horizon, you will not. That is because while you are level in pitch, you are actually falling, while the power is pulling you forward. If you count two seconds and then cut power, your nose will immediately drop into a stall, especially if aided by a sharp pull on the stick.
The learning point of that is we all have an AoA indicator. It is called the stick. Every plane is different, but as a general rule the stick needs to be well aft of neutral to stall. So don't do that when you are slow.
Let me give an illustration. Let's say you pull vertical up and hold it. When you are below Vs, will you stall? Nope. You can continue flying straight up until you hit zero mph.
Now let's say Vs is 54mph. When you hit 50, you push forward to level. When you hit level at 50mph, will you stall? Depends on what you do with the stick. If you keep power in and pull the stick back just enough to keep the nose on the horizon, you will not. That is because while you are level in pitch, you are actually falling, while the power is pulling you forward. If you count two seconds and then cut power, your nose will immediately drop into a stall, especially if aided by a sharp pull on the stick.
The learning point of that is we all have an AoA indicator. It is called the stick. Every plane is different, but as a general rule the stick needs to be well aft of neutral to stall. So don't do that when you are slow.
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Ed Haywood
Final Approach
On to spin recovery. TBH you guys are over thinking that one. Stop the rotation, break the stall, recover from the dive.
A spin is essentially a stable equilibrium when one wing is stalled and the other is flying. The flying wing goes around in a corkscrew, while the stalled wing falls straight down. A spin requires yaw and roll in the same direction.
To stop a spin, as discussed PARE is the most reliable method for most planes. Power off because it can raise the nose and flatten the spin, causing control blanking of the rudder. Aileron neutral because pro spin aileron accelerates yaw. Rudder slows yaw so you can get more airflow on the stalled wing. Elevator breaks the stall.
Every plane spins differently, and the attitude varies as the spin oscillates and develops, but in general many planes settle into a 60 to 80 degree nose down attitude. That means when you break the stall, you will be in a steep dive. Your most important task is recovering from that dive.
In theory, you could re-stall the aircraft if you pulled back too soon. However, as a practical matter you accelerate very quickly when the stall breaks. Unless you are a kung fu master, I doubt you have the reflexes, unless you shove it forward to break the stall, then rearward all in one motion.
In theory you could over G the aircraft. But you gotta be moving very fast and pull the controls hard and far to do that. Va is more a theoretical limit than an actual one. As a practical matter, you can pull firmly well above Va with no problem. Just don't do it full and abrupt. Smoothly loading up the plane to near the G limit is better than letting it continue to accelerate past Vne. That's when things get bad.
So, spin recovery is pretty simple. P-A-R, stick forward to break the stall, then stick back to pull out of the dive. As long as you don't hold it in the dive with full power or abruptly jerk the controls back, it won't be a problem.
So after all that, what was the specific situation you wanted me to test? BTW I have a Decathlon, not an Airbatic.
A spin is essentially a stable equilibrium when one wing is stalled and the other is flying. The flying wing goes around in a corkscrew, while the stalled wing falls straight down. A spin requires yaw and roll in the same direction.
To stop a spin, as discussed PARE is the most reliable method for most planes. Power off because it can raise the nose and flatten the spin, causing control blanking of the rudder. Aileron neutral because pro spin aileron accelerates yaw. Rudder slows yaw so you can get more airflow on the stalled wing. Elevator breaks the stall.
Every plane spins differently, and the attitude varies as the spin oscillates and develops, but in general many planes settle into a 60 to 80 degree nose down attitude. That means when you break the stall, you will be in a steep dive. Your most important task is recovering from that dive.
In theory, you could re-stall the aircraft if you pulled back too soon. However, as a practical matter you accelerate very quickly when the stall breaks. Unless you are a kung fu master, I doubt you have the reflexes, unless you shove it forward to break the stall, then rearward all in one motion.
In theory you could over G the aircraft. But you gotta be moving very fast and pull the controls hard and far to do that. Va is more a theoretical limit than an actual one. As a practical matter, you can pull firmly well above Va with no problem. Just don't do it full and abrupt. Smoothly loading up the plane to near the G limit is better than letting it continue to accelerate past Vne. That's when things get bad.
So, spin recovery is pretty simple. P-A-R, stick forward to break the stall, then stick back to pull out of the dive. As long as you don't hold it in the dive with full power or abruptly jerk the controls back, it won't be a problem.
So after all that, what was the specific situation you wanted me to test? BTW I have a Decathlon, not an Airbatic.
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dtuuri
Final Approach
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Compare the usual loss of altitude from the diving part of spin recovery to a maximum (optimal) effort realized by pulling more and doing it sooner. My suspicion is there's a significant conservation of altitude to be had which has been under-emphasized.
MauleSkinner
Touchdown! Greaser!
I think that’s not exclusive to spin recoveries, but stall recoveries in general. In jets I often see 60 knots of speed increase before anything resembling a level-off, much less a climb, is achieved. And that’s not even from a stalled condition, just an approach to stall indication.
Frankly I like the fact that the FAA started requiring simulator stalls “in the operational environment” 10+ years ago. A stall recovery from 400 feet with the GPWS yelling at you puts a little more urgency on the pitch-up.
Ed Haywood
Final Approach
I've experimented with that before and your suspicion is correct.
The airspeed will be stable during a fully developed spin. Once you break the stall, you will see a sudden and drastic increase in the ASI. If you are concerned about altitude loss, a firm pull out from the dive before you build up too much speed is definitely necessary and should be taught.
But from a safety standpoint, recognizing a developing spin is the best way to limit altitude loss.
Ed Haywood
Final Approach
Here's a spin video I did years ago. It is a competition style recovery, which includes a vertical down line. But it is useful to see how the pitch angle stabilizes as the spin develops. How steep would you guess that dive is for the last half turn?
Also note the windshield brace alignment with the road below. Not accidental. That's one of my demo points when I show spins to pilot friends. People are afraid of not recovering, but most aircraft approved for spins have large rudders and a LOT of control over the rotation.