Decathlon crash at Indonesian airshow
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North Shore
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Re: Decathlon crash at Indonesian airshow
Thanks for posting, bmc! I was going to, but you beat me to the punch.
Looks like he descended while inverted, and then was too low to roll out of it. That being said, it looked like a pretty lazy roll back to the right way up - you'd think that if he had any recognition of where he was, then he would have yarded it around quite sharpish?
'Course, I've never done any aerobatics... Any comments Hedley, C-ZGRO?
Looks like he descended while inverted, and then was too low to roll out of it. That being said, it looked like a pretty lazy roll back to the right way up - you'd think that if he had any recognition of where he was, then he would have yarded it around quite sharpish?
'Course, I've never done any aerobatics... Any comments Hedley, C-ZGRO?
Say, what's that mountain goat doing up here in the mist?
Happiness is V1 at Thompson!
Ass, Licence, Job. In that order.
Happiness is V1 at Thompson!
Ass, Licence, Job. In that order.
Re: Decathlon crash at Indonesian airshow
Deleted.
Last edited by Hedley on Thu Apr 07, 2011 6:46 am, edited 1 time in total.
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Big Pistons Forever
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Re: Decathlon crash at Indonesian airshow
If you watch the flight path of the aircraft from the very beginning of the video it is one long curve right into the ground. From what I can see there was never any attempt to establish and then hold a line especially as the aircraft rolled inverted. The pilot was influencing the roll rate but gravity was in charge of everything else. Hedley is right on...... this guy had no business doing aerobatics below 2000 ft AGL......and paid a very heavy price when his ego wrote checks his ability could not cash.
Re: Decathlon crash at Indonesian airshow
Its actually quite tricky to do a good level roll in the Decathlon. You need boot loads of rudder and the stick goes waaaay forward. Far safer in a slow rolling plane to toss the nose up a bunch to do it ballistically. To be fair this guy must have had a bit of practice so its possible there was some other problem such as a loose belt or seat frame. Ive done a few surface level rolls in a Decathlon but i toss the nose up 45 degrees first. Ill do them flat in the Pitts but it is very easy to slow roll without altitude or heading change.
Peter
Peter
Re: Decathlon crash at Indonesian airshow
I learn so much from you guys.
Two of you used the term ballistically. What does that mean?
Two of you used the term ballistically. What does that mean?
bmc
Re: Decathlon crash at Indonesian airshow
Basically it means that the aircraft follows a ballastic trajectory, just like a bullet or a ball would. It arcs its way along a parabola climbing initially, then descending but the climb and descent are about the same height.
Another way to think about it. If you shoot a gun, or an arrow at a target you aim a bit high so that as the bullet/arrow travels it climbs initially and then drops. If you were to shoot the arrow/bullet 'flat' it would never hit the target because it would drop before getting there.
So, we can fly a plane much like a bullet while its rolling. You litterally 'toss' the nose up, i.e. a brief pull to get a positive rate of climb then you relax the back pressure and immediately start a roll. This means that you don't have to do anything special during the roll to end up at your starting altitude when finished. You just keep the ailerons full over, the elevator more or less neutral with minimal fuss on the rudder. If you got the right climb angle at the start it all just 'works out'.
The alternative or slow roll has no 'toss' up at the beginning and you need to fly the plane fully around the roll. This means you need to transition from using the wing as your primary source of lift to the fuse which must be presented at a good 10-15 degrees AOA relative to the airflow to generate enough lift as you go through knife edge. Then you need to compensate for being inverted with a healthy dose of forward stick, again 10-15 degrees or more. Then, the hardest part, the last 90 degrees you have to reverse the rudder from the first 90 degrees and get the nose up again to fly knife edge. Even if you do all of this perfectly a plane like a Decathlon is going to descend a bit.
What we were saying is that if you lack the skill to fly it flat then tossing the nose up and flying it ballistically is a better alternative. Mind you, if you you can't fly it more or less flat you should not be doing airshows anyway.
This pilot also appears to have not only tried to fly it flat, but also paused it inverted while descending..
Here is an extreme example. http://www.youtube.com/user/petera1000 a very safe surface level roll flown ballistically so that it actually ends up 200' heigher than started. Very safe and frankly for spectators is much more fun to watch with smoke than something flat and dangerous.
Another way to think about it. If you shoot a gun, or an arrow at a target you aim a bit high so that as the bullet/arrow travels it climbs initially and then drops. If you were to shoot the arrow/bullet 'flat' it would never hit the target because it would drop before getting there.
So, we can fly a plane much like a bullet while its rolling. You litterally 'toss' the nose up, i.e. a brief pull to get a positive rate of climb then you relax the back pressure and immediately start a roll. This means that you don't have to do anything special during the roll to end up at your starting altitude when finished. You just keep the ailerons full over, the elevator more or less neutral with minimal fuss on the rudder. If you got the right climb angle at the start it all just 'works out'.
The alternative or slow roll has no 'toss' up at the beginning and you need to fly the plane fully around the roll. This means you need to transition from using the wing as your primary source of lift to the fuse which must be presented at a good 10-15 degrees AOA relative to the airflow to generate enough lift as you go through knife edge. Then you need to compensate for being inverted with a healthy dose of forward stick, again 10-15 degrees or more. Then, the hardest part, the last 90 degrees you have to reverse the rudder from the first 90 degrees and get the nose up again to fly knife edge. Even if you do all of this perfectly a plane like a Decathlon is going to descend a bit.
What we were saying is that if you lack the skill to fly it flat then tossing the nose up and flying it ballistically is a better alternative. Mind you, if you you can't fly it more or less flat you should not be doing airshows anyway.
This pilot also appears to have not only tried to fly it flat, but also paused it inverted while descending..
Here is an extreme example. http://www.youtube.com/user/petera1000 a very safe surface level roll flown ballistically so that it actually ends up 200' heigher than started. Very safe and frankly for spectators is much more fun to watch with smoke than something flat and dangerous.
