Van's Air Force
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Looking for Base to final Stall Video
- Thread starter mfleming
- Start date
RV8JD
Well Known Member
newt
Well Known Member
Was it this one?
https://www.youtube.com/watch?v=8wPCaazpU5k
The video is from a while ago. Eddie's a bit greyer now
- mark
https://www.youtube.com/watch?v=8wPCaazpU5k
The video is from a while ago. Eddie's a bit greyer now
- mark
I don't think it was that one but it's a good one.
Was it this one?
https://www.youtube.com/watch?v=8wPCaazpU5k
The video is from a while ago. Eddie's a bit greyer now
- mark
I think this might have been it!
EDIT: I watched it a couple more times...That's it
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RV8JD
Well Known Member
You mean like this one by Mike (Vac) Vaccaro from 250' AGL?
That video is from this post with his notes, warnings and cautions that go with the video:
From this thread:
And another good post by Vac from that thread:
As someone else said, knowing HOW to do a turn back is probably just as important as knowing WHEN to do a turn back. In many, if not most, engine outs on takeoff straight ahead is probably preferred.
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skylor
Well Known Member
Coordination
Actually, nice short and succinct demonstration of how NOT to use the rudder! This should not happen in an RV if the turn is coordinated!
Skylor
Actually, nice short and succinct demonstration of how NOT to use the rudder! This should not happen in an RV if the turn is coordinated!
Skylor
Desert Rat
Well Known Member
^^^^
This.
Something else that they didn't specifically mention in the video (but we should all have learned when we started flying) is that your stall speed is going up in a turn due to the g loads.
Very cool to see it in an RV, thanks for that.
This.
Something else that they didn't specifically mention in the video (but we should all have learned when we started flying) is that your stall speed is going up in a turn due to the g loads.
Very cool to see it in an RV, thanks for that.
fixnflyguy
Well Known Member
Experienced pilot story..
I spoke with a fellow pilot I know who actually experienced it (in an RV), and in his words "Its was instantaneous and without warning". He survived, the plane did not. I often do a 180 degree downwind to final close pattern approach in my RV-4 and any crosswind will tempt you to skid/slip to stay on center, which mishandled will put you deep in the danger zone. Plan for the go-around and never think twice about it.
I spoke with a fellow pilot I know who actually experienced it (in an RV), and in his words "Its was instantaneous and without warning". He survived, the plane did not. I often do a 180 degree downwind to final close pattern approach in my RV-4 and any crosswind will tempt you to skid/slip to stay on center, which mishandled will put you deep in the danger zone. Plan for the go-around and never think twice about it.
Ed_Wischmeyer
Well Known Member
Data shows more to it than stall-spin
A study of 551 RV-series NTSB reports indicated that botched steep turns are as significant as and may be more common than stall spin. In the same way that a botched steep turn at altitude can result in quick altitude loss, a botched steep turn at low altitude can result in a quick altitude loss.
Here's a presentation on base to final accidents, from NAFI's Mentor Live a year ago, and this webinar has has had north of 4,500 views:
https://www.mentorlive.site/program/60.html
Too much rudder can help result in a botched steep turn, so a skidding turn doesn't have to result in a spin. That video is shown in the presentation, demonstrated in the RV-9A.
Here's an eye-opener. A botched steep turn with that same severe altitude loss can be ball-centered and at optimum angle of attack:
https://www.youtube.com/watch?v=7pytF1zwOFo
(I wasn't trying for optimum AOA, I was just doing the demonstration, eyes outside the cockpit.)
Observe that because a botched base to final turn can occur at "optimum" AOA, an angle of attack indicator will not give any warning.
I've presented on base to final several times, including the EAA Pilot Proficiency Program at AirVenture, and at the end of this month, I'll be presenting again at the National Association of Flight Instructors Summit in Lakeland. I'd love to discuss this with any RV-CFIs who are going to be there.
Smokey, the RV-9A, might be flyable again next week, and I can again demonstrate base to final and the rest of the Expanded Envelope Exercises®, free, in Savannah.
A study of 551 RV-series NTSB reports indicated that botched steep turns are as significant as and may be more common than stall spin. In the same way that a botched steep turn at altitude can result in quick altitude loss, a botched steep turn at low altitude can result in a quick altitude loss.
Here's a presentation on base to final accidents, from NAFI's Mentor Live a year ago, and this webinar has has had north of 4,500 views:
https://www.mentorlive.site/program/60.html
Too much rudder can help result in a botched steep turn, so a skidding turn doesn't have to result in a spin. That video is shown in the presentation, demonstrated in the RV-9A.
Here's an eye-opener. A botched steep turn with that same severe altitude loss can be ball-centered and at optimum angle of attack:
https://www.youtube.com/watch?v=7pytF1zwOFo
(I wasn't trying for optimum AOA, I was just doing the demonstration, eyes outside the cockpit.)
Observe that because a botched base to final turn can occur at "optimum" AOA, an angle of attack indicator will not give any warning.
I've presented on base to final several times, including the EAA Pilot Proficiency Program at AirVenture, and at the end of this month, I'll be presenting again at the National Association of Flight Instructors Summit in Lakeland. I'd love to discuss this with any RV-CFIs who are going to be there.
Smokey, the RV-9A, might be flyable again next week, and I can again demonstrate base to final and the rest of the Expanded Envelope Exercises®, free, in Savannah.
Some points to ponder
Skylor is correct—it’s all about rudder coordination, which is why we put a slip/skid ball on our AOA indexer (visual display) and move the AOA tone left and right with the ball, so the pilot can hear when the rudder is not properly coordinated.
The video examples at the beginning of this thread are examples of a “skidding” departure, i.e., stalling the airplane while trying to “rudder” around the base turn. There is a bit of a an old wive’s tale that you can’t depart (lose control) in a “slipping” turn, but that’s not correct. While you have to force the airplane to react (unlike a skid, where it immediately snap rolls when the critical angle of attack is exceeded), it will eventually auto-rotate, but not until it’s provided lots of aerodynamic warning. Notice the ratchet effect prior to rolling over the top into a spin: https://youtu.be/I6tBNnoaB6w.
If the airplane is properly coordinated, a stall may occur at very low altitude, and recovery is possible: https://youtu.be/BPD5xk1wgOw. Obviously, the right answer is to go around. This was a controlled demonstration that illustrates the additional SA that accurate AOA cues provide when maneuvering.
As was pointed out, an airplane can stall at any airspeed in any attitude (and stall SPEED increases with G load). Ed is correct, it’s entirely possible to enter a steep spiral and increase airspeed and AOA simultaneously (all the way into an accelerated stall). Ed doesn’t bother to stall the airplane in his video, but I do in the second demonstration in this video: https://youtu.be/PKWvCgQ-uzM. This occurs when the pilot has mis-managed what fighter pilots call the lift vector (where the lift is pointing) and the velocity vector (where the airplane is going, or the vertical component of the “flight path”). In this video, it’s easy to see the horizon, the standby airspeed indicator and listen to the angle of attack. If you aren’t familiar with our work, I clipped this video from a slightly longer maneuvering demonstration you can view here: https://youtu.be/JxBLS8JL6Mo.
The “impossible turn" is not impossible, but it his highly dependent on many factors, not the least of which is aircraft performance. The ability to turn back is also highly dependent on ambient conditions, length of runway etc. The video of my turning back from 250’ AGL posted above is not a good example. At the time we shot that video, we had not yet conducted engine-off testing; so, we were not properly compensating for residual thrust (thanks again Skylor for calling us to task on that—huge input!). Turns out actual engine off glide angle is steeper than glide angle in IDLE. After conducting engine-off experiments at altitude, we determined that we could replicate actual engine-off performance in the RV-4 by applying flaps 40 with power at IDLE for low-altitude test. But things get even more aerodynamically complicated, because the RV-4 has such good climb performance, it actually continues to gain altitude AFTER engine failure as I transition to an on speed AOA condition for turnback. We are currently modeling this type of edge case for an iPhone app that integrates aircraft performance with ambient conditions to determine whether a turnback is practical under actual conditions during initial climb segment. Here are more representative turn backs: https://youtu.be/aIvBnva1At8.
I'm not the smartest guy in the room. I've had the benefit of some good training and experience; and I have a good AOA system in my airplane, courtesy of a team of really talented folks that volunteer their time and ask nothing in return. John Boyd broke the code on energy maneuverability a long time ago, and my AOA system effectively allows me to hear energy cues real time. That's a tremendous amount of SA for a knuckle-dragger like me. The military cracked the loss-of-control code over a half-century ago. Whether the airplane spins into the ground or spirals into the ground is a moot point. We changed the way we did business in the military by adapting AOA and incorporating Boyd's work into how we teach aircraft handling. We can do the same in GA/EAB or we can continue to suffer current mishap rates.
Fly safe,
Vac
Skylor is correct—it’s all about rudder coordination, which is why we put a slip/skid ball on our AOA indexer (visual display) and move the AOA tone left and right with the ball, so the pilot can hear when the rudder is not properly coordinated.
The video examples at the beginning of this thread are examples of a “skidding” departure, i.e., stalling the airplane while trying to “rudder” around the base turn. There is a bit of a an old wive’s tale that you can’t depart (lose control) in a “slipping” turn, but that’s not correct. While you have to force the airplane to react (unlike a skid, where it immediately snap rolls when the critical angle of attack is exceeded), it will eventually auto-rotate, but not until it’s provided lots of aerodynamic warning. Notice the ratchet effect prior to rolling over the top into a spin: https://youtu.be/I6tBNnoaB6w.
If the airplane is properly coordinated, a stall may occur at very low altitude, and recovery is possible: https://youtu.be/BPD5xk1wgOw. Obviously, the right answer is to go around. This was a controlled demonstration that illustrates the additional SA that accurate AOA cues provide when maneuvering.
As was pointed out, an airplane can stall at any airspeed in any attitude (and stall SPEED increases with G load). Ed is correct, it’s entirely possible to enter a steep spiral and increase airspeed and AOA simultaneously (all the way into an accelerated stall). Ed doesn’t bother to stall the airplane in his video, but I do in the second demonstration in this video: https://youtu.be/PKWvCgQ-uzM. This occurs when the pilot has mis-managed what fighter pilots call the lift vector (where the lift is pointing) and the velocity vector (where the airplane is going, or the vertical component of the “flight path”). In this video, it’s easy to see the horizon, the standby airspeed indicator and listen to the angle of attack. If you aren’t familiar with our work, I clipped this video from a slightly longer maneuvering demonstration you can view here: https://youtu.be/JxBLS8JL6Mo.
The “impossible turn" is not impossible, but it his highly dependent on many factors, not the least of which is aircraft performance. The ability to turn back is also highly dependent on ambient conditions, length of runway etc. The video of my turning back from 250’ AGL posted above is not a good example. At the time we shot that video, we had not yet conducted engine-off testing; so, we were not properly compensating for residual thrust (thanks again Skylor for calling us to task on that—huge input!). Turns out actual engine off glide angle is steeper than glide angle in IDLE. After conducting engine-off experiments at altitude, we determined that we could replicate actual engine-off performance in the RV-4 by applying flaps 40 with power at IDLE for low-altitude test. But things get even more aerodynamically complicated, because the RV-4 has such good climb performance, it actually continues to gain altitude AFTER engine failure as I transition to an on speed AOA condition for turnback. We are currently modeling this type of edge case for an iPhone app that integrates aircraft performance with ambient conditions to determine whether a turnback is practical under actual conditions during initial climb segment. Here are more representative turn backs: https://youtu.be/aIvBnva1At8.
I'm not the smartest guy in the room. I've had the benefit of some good training and experience; and I have a good AOA system in my airplane, courtesy of a team of really talented folks that volunteer their time and ask nothing in return. John Boyd broke the code on energy maneuverability a long time ago, and my AOA system effectively allows me to hear energy cues real time. That's a tremendous amount of SA for a knuckle-dragger like me
. The military cracked the loss-of-control code over a half-century ago. Whether the airplane spins into the ground or spirals into the ground is a moot point. We changed the way we did business in the military by adapting AOA and incorporating Boyd's work into how we teach aircraft handling. We can do the same in GA/EAB or we can continue to suffer current mishap rates.Fly safe,
Vac
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