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Another stall spin crash (usa)


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Amazing footage there! Imagine the cost involved just so mankind can continue to find quicker easy ways to blow each other up? The human species hasn’t progressed far at all since they left the caves with clubs!🙁

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8 hours ago, kgwilson said:

Nope, Bluetooth is complex but entirely explainable with zeros and ones, algorithms using packet data and spread spectrum technology over very short range in the 2.4ghz spectrum 

 

Oh, really!?  Explain this then: 

 image.jpeg.1a6a0804a50254f32dace81d764cdbf6.jpeg

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Drones can do anything a manned aircraft can do and more these days. But even in 1965 the Hawker Siddeley Trident was the first commercial aircraft that could land itself. Originally designed by de Havilland it was capable of landing in complete whiteout conditions & it was only due to the fear of failure from Aviation Authorities and the public that it was eventually not allowed to do so. It was the most advanced and first trijet built, originally designed in 1957.

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We can lose it coming, and we can lose it going ...  and sometimes be lucky enough to get away with it, anyway.

 

But if the second one had have been 'fiery' then the outcome would have been dire.

 

As usual, lots of interesting discussion in the YT comments. 

"Watch on YouTube" to see them.

 

 

 

 

 

Edited by Garfly
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3 hours ago, Garfly said:

 

STOL Pilot Warned To ‘Lower Your Nose’ Before Crash

 

That’s a bit confronting… I’m in Nebraska now. 45 sec and 15 sec before crash warning to lower nose! I’m checking with my CFI if he knows more.

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All the theories point to a convex upper surface causing a lower pressure and the lower surface has a higher pressure, So lift is caused by the wing being pushed from high to low pressure.

I never subscribed to the theory of the low pressure above the wing providing the major part of lift. The lower part of the wing deflects air downwards and there is an equal and opposite reaction from the wing, plus a little bit of lift from the lower pressure above.

I just wonder why when I am cruising along and look at the top of my wing, the dacron part behind the main spar seems to be sucked down into the wing.

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On most slower type planes the top surface does provide the majority of the lift. It's easily proven by the pressure readings.  As you go faster the AoA decreases. That'll cause the rear part of the upper surface to be  depressed but the lower wing of a DH82 normally show upward  movement of the top  surface on the lower wing. You can't see the top one. Nev

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8 hours ago, Yenn said:

I just wonder why when I am cruising along and look at the top of my wing, the dacron part behind the main spar seems to be sucked down into the wing.

Yenn mine is the opposite- the fabric billows up in flight, indicating a low pressue area above the wing. The fabric is not as tight as I’d like, because when shrinking it onto the wing I winmped out of applying the last, hottest run with the iron. Loose enough, in fact, to show slight ripples at very low shadow angles, when the GoPro is mounted on the rudder and she’s flying into sun.

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Decathlon has an almost symmetrical wing for aerobatics. Therefore…AOA related lift. Lower surface is exposed to the airflow and lifting force created beneath the exposed surface like holding your hand out a window and exposing a flat edge. Lift and drag.

 

Upper surface is directing the airflow downward. Newtons 3rd law. Downward directed airflow and equal and opposite reaction is lift. That’s all easy to understand. High and low pressure isn’t easy to understand. 

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You don't need any aerofoil to fly. A flat board will provide the lift when the angle of attack and thrust provides enough downward force to overcome the gravity of the mass of the machine. It will just be hopelessly inefficient.

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On 2/6/2022 at 6:17 PM, Garfly said:

 

STOL Pilot Warned To ‘Lower Your Nose’ Before Crash

 

This kind of illustrates why I think it is best to train for stalls by putting the stick well forward and fast. If you are practicing stalls, easing the stick forward will break the stall, but if you are taken by surprise, you need to act faster and more. When the plane started turning left, things were so far gone that big correction was needed and fast. The last thing that guy needed was a memory of his instructor chiding him for losing too much height on recovery. 

 

I am not worried that you might lose 200 ft when you are 100 ft above the ground. Even a full stalled aircraft has a MUCH bigger horizontal velocity that a vertical velocity. Hitting the ground fully stalled is way better than hitting the ground nose first.  

 

If you are descending at 500 fpm, you are descending at 5 knots. So if you hit the ground before you have broken the stall, you will survive unless you hit something. If you spin in at 40 kts, you hit at 40 kts. 

 

This is a safety issue, so I welcome dissenting views..   

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1 hour ago, APenNameAndThatA said:

This kind of illustrates why I think it is best to train for stalls by putting the stick well forward and fast. If you are practicing stalls, easing the stick forward will break the stall, but if you are taken by surprise, you need to act faster and more. When the plane started turning left, things were so far gone that big correction was needed and fast. The last thing that guy needed was a memory of his instructor chiding him for losing too much height on recovery. 

 

I am not worried that you might lose 200 ft when you are 100 ft above the ground. Even a full stalled aircraft has a MUCH bigger horizontal velocity that a vertical velocity. Hitting the ground fully stalled is way better than hitting the ground nose first.  

 

If you are descending at 500 fpm, you are descending at 5 knots. So if you hit the ground before you have broken the stall, you will survive unless you hit something. If you spin in at 40 kts, you hit at 40 kts. 

 

This is a safety issue, so I welcome dissenting views..   

 

 

The writer of this article in Aviation Safety Mag seems to agree.   His essay is long and detailed and deserves to be read in full, but I excerpt a few bits to indicate the drift.

 

What a Pushover

Unloading the wing can prevent a stall or spin, but only if you're aggressive enough

 

https://www.aviationsafetymagazine.com/features/what-a-pushover/

 

 

" .... //

If the airspeed is rapidly approaching stall speed, even with full power, you need to act aggressively in getting the nose down, and this may require unloading the wing to 0 g.  You can prevent a stall and maintain some measure of control. If a crash is inevitable, it is better to crash wings level with some control than to crash out of control and with the airplane in a bank.

 

.... //

The altitude loss that results from such an aggressive pushover is not much greater than in a normal stall recovery, but by unloading the wing you will prevent both a stall and a possible spin.You will be able to continue flying the airplane until the recovery is complete, and not experience a momentary loss of control as in a full stall or spin entry.

 

.... //

...  when the airspeed is bleeding off rapidly, aggressively pushing the airplane over to a 0 g state will keep you from stalling and spinning. It retains your lateral control and gives the airplane higher acceleration or slower deceleration until you can get the airplane flying normally again.  Wing loading may seem like the province of aeronautical engineers, but knowing the dynamics of reducing the load may give you the ammunition you need to kill a low-altitude stall/spin before it happens."

 

by Michael Friese

Michael Friese is an ATP, CFII and airframe mechanic. He is a former assistant chief pilot at Embry-Riddle and currently flies for the U.S. government.

 

 

 

 

And, right on cue, unfortunately, another illustration ... and similar analysis and advice from Blancolirio.

 

 

 

Edited by Garfly
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Punching (almost)the stick forward at the right time is useful. Once the nose is well down there's a minimum height you need to recover no matter if you're an ace. If you  are nearly stopped  (Airspeed) the controls won't do much. Rarely will you go straight into  a spin. You might lose a few hundred feet to settle in to one or the plane might start to recover by itself in some cases.. A spin rate of descent is close to constant once stabilised and in some low wing loaded planes is survivable, whereas going vertically in on the spinner is usually not survivable. In that position the speed will build up rapidly but you may not have enough height to recover and possibly stall the plane again trying to. Nev

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15 hours ago, APenNameAndThatA said:

If you are descending at 500 fpm, you are descending at 5 knots. So if you hit the ground before you have broken the stall, you will survive unless you hit something. If you spin in at 40 kts, you hit at 40 kts. 

 

This is a safety issue, so I welcome dissenting views..   

I had to do the math… yes, 500 X 60 = 30000 = 5kn 
 

I used the SPLAT calculator on a 100kg person at 500fpm/ 2.6 meters per second.. that’s the equivalent of jumping off a 1ft wall. So many variables of course. Real life a 1ft drop in … meaning your aircraft in the hangar and 1ft off the ground and somebody cuts the rope is going to be quite a jolt. So, in a landing no flare at all it’d be nasty. I think ground affect must cushion all those flight school events like this so they aren’t terrible. 
 

As you say though, a 1ft drop is infinitely better at 5kn than a 100ft drop in at 40kn.

 

I had drinks last night with a guy who was at paragliding event last year south of Phoenix. He was unfortunately witness to a motorised paraglided take off and at 100ft the chute tangled and the guy died. Gusty conditions apparently. This is why we have proper wings. You have a fair chance of fixing things that go wrong and obviously work really hard not to be in that position in the first place. 

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You also would have to take into account the ‘give’ factor in the U/C such as tires, the oleo components (if any) as well as the seat cushion/s etc when arriving in a somewhat normal attitude and the crumple factor of the airframe if going more vertical, none of these would come into play impacting the ground as a stand alone human body. The human body can take a lot of punishment but extreme blunt force trauma usually means it’s  lights out, for good!

 

Edited by Flightrite
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On 26/05/2022 at 11:27 AM, F10 said:

I was at a small country airshow, in South Africa, this guy in a microlight, similar to a thruster, but with a pusher engine/prop, flew down the runway and started doing steep turns in front of the crowd, (rapidly turning downwind). Unfortunately a strong surface wind of 15-20 knots. She staggered around in the first one and he kept turning...I turned back to a mate and said "this guys going to kill himself". As those last words were spoken, I heard the sickening metallic bang. I whipped around and there it was, tail straight up, nose first into the ground. Very not good.  

You were there; I wasn't, but I can think of three possibilities for this crash; 

1. He did something wrong when you weren't watching

2. Wind shear

3. Observation mismatch between what appears to be happening and kinetic energy.

 

If the slab of air we are flying in is undisturbed and moving over the ground in a constant direction, we can do a controlled Rate 1 turn in the slab and the ASI will remain stable, but if you hit some wind shear in that turn the ASI will change. Wind shear is invisible; I've had two big ones that nearly put me into the ground, the first one where an instructor was there to save me; the second one where I beat the CFI to the throttle. One of my CFIs was killed when he encountered windshear after takeoff in a crop duster. These are violent air movements.

 

In open wheel sprintcar racing where a following car slams a front tyre into the rear tyre of the car in front, there's usually a spectacular crash. In the following car, the nose shoots up and the rear of the car gets two or three metres in the air then appears to fall, and just as the spectators breathe a sigh of relief the tail flies up and goes high into the air in a series of forward somersaults. Logic tells you that an object that's falling can't just rise again, but we can't see kinetic energy. What has actually happened is at the beginning of contact the downward force of the trailing car's tyres lock on to the upward force of the lead cars tyres creating the first upward result of the front of the car then fractionally later both tyres collapse like a golf ball and then rebound in a straight  line with a much greater force.

 

In RC flying you don't have an ASI so you have to judge the speed upwind on takeoff, crosswind on crosswind and base, downwind on downwind, and upwind again on final. This becomes a subconscious adjustment. When there's a stiff wind blowing down the active strip, there's a VERY discernable difference in observed speed flying upwind compared to downwind, where at times they look to be supersonic. After a couple of crashes you resist the urge to slow them down so you have the same groundspeed both ways and just let physics take its course.

 

If you were to practice the rectangle at circuit height your eye would record three distinctly different speeds, one upwind, one down wind and one on the two crosswind legs. If you wanted to make the rectangle shorter by making the base turn at midfield, you wouldn't change the speeds, just let nature take it's course. You can't see the energy of the wind in your controls, but it doesn't matter because you're trained for the speed differences. Like a full sized aircraft, if you thought "Gee, it's going too fast downwind, I'll pull the throttle back", you'd stall. If you decided to land downwind just for fun, you would only use normal throttle reduction, but expect to take three or four times the distance to land.

 

In full size aircraft, some instructors, to help confused students resort to ground references like "Make your final turn around the church", but your final turn should be at the point where you will flare at the optimum distance down thr runway, not before the keys if there's a howling headwind. If you don't eventually discard these crutches, you'll finish up reacting to what you see and not to kinetic energy. If you see the ASI changing in a constant slab of air, it's most likely that you have "adjusted" something subconsciously, like trying to stop yourself going "too fast" as you come around to the downwind sector.

 

If you were looking up at that aircraft from the ground and it had been flying a few circles over the runway, as it turned out of the downwind sector to the upwind sector, you would be cheering on the pilot to get the throttle on or stall because he "appeared" to be going too slow.

 

 

 

 

 

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