_MOL_
05-12-2006, 03:28 AM
As I posted in another thread by birdy in "theory of flight" I have lost a friend a couple of years ago and need to talk about now.
Also I would really like that some of our more knowledgably friends on this forum to look through the video of the accident. (Don’t worry, the end is not caught on video, so no blood ect)
It goes as follows:
I lost a friend a couple of years ago due to partial/blade stall I believe it was.
When spectators were around he usually did some manoeuvres I can't even start to describe. I tolled him over and over again that it was lethal to do so, and explained him the aerodynamic consequences of what he was doing, but I guess he was not clever enough to understand it, or I didn't explain things good enough, or he just didn't care.
Anyway, he usually did these manoeuvres in reasonable calm air, but on that day the wind was about 20- gusting to 30 kts, and I think he forgot all about that in the heat of battle.
- I lost my best friend.
Somebody filmed the accident too.
He was flying a light gyro with a 27' McCutchen rotor (maybe on minimum limit load – in fact I believe it was minimum loaded – turning just under 300 according to late friend)
He was cruising around in about 50' alt doing some "gyro manoeuvres".
The one he specially liked to do was a kind of quick flat spin 360dg turnaround back to same direction with minimum loss of altitude, which is a quick 360dg turnaround without much bank attitude.
I didn’t see the accident myself (fortunately for me) but according to the film at least up to the point where it goes wrong he was doing exactly that, but with in high wind.
At a point he does a low pass in 5' from a lower point, (runway rises) from where the wind was not so strong, pulled up, vent vertically up into the strong wind. When things started to go wrong the ground speed is zero and altitude was about 120'. Nose attitude was high and it seemed that he then tried to turn back downwind, not much with a bank but rather that flat turn. After that the video is pointed towards the ground. A few large slap sounds followed by something that folded together on the ground.
Witness says that he was almost vertically in attitude and seemed to be on the edge to go over the top backwards, but then turned on its side and went straight to the ground, and fluid was coming out during the fall. Our NTSB equivalent here in Denmark found nothing wrong with gyro, and stated it was pilot error.
Though they didn’t describe what went wrong but IMHO and from what I can see and hear from the film I believe he realised he was in deep **** when he found himself vertically or with high nose attitude with no ground speed.
When looking at the film I think he then tried to lower the nose and might have thought that he couldn’t regain control that way and then turned around to gain flight speed again. Why I don’t know, because it is wrong to do that. But when he turned around I believe the violent stick and rudder input lead to blade/partial stall, hence those loud slap sounds. He then lost lift on one side of the rotor for a split second and the gyro went into a 90 dg bank with no airspeed, and continued like this to the ground.
There was no bunt over, wreckage showed no sign of rudder or prop strike.
You can't really see what happened in the end but I do not believe he initially was doing negative G’s on the top of the climb; he’s attitude was not that vertical. As I see it he vas climbing vertical but maybe with a 45dg attitude. At one point I believe I can see the nose wheel and instrument panel. The position of this is almost level but with a 90 angle to the wind (sideways), still no ground speed, so that will be no airspeed too. If he did a violent manoeuvre with the rudder pedals and maybe the stick too to get into downwind he would have experienced the partial stall witch ended up in loss of lift on one side of the rotor. I believe so anyway.
After the loud slabs the rotor sounded like it lost rpm fast, (on that point he would have been sliding sideways into the ground) and the engine then stopped. According to our NTSB the engine stopped during the fall where no positive G’s feed the carb. Propeller was not damaged other than from the fall.
At one point I had the impression that he chopped the throttle before the event or during the event.
Why he didn’t just level the thing and continued forward/down and just rode it out by making a forward decent to the ground beats me.
Maybe the engine failed or he couldn’t lower the nose and decided to do the turn into downwind rather than end up in a tail slide. Who knows, it’s hard to tell. Our NTSB didn’t find anything wrong with engine, but subsequent I found a broken outlet fitting on the electrical fuel pump. When I examined the wreckage the fuel line was still attached to the pump but when I began to disassemble the wreak, it just fell off. Note to this: our NTSB didn’t disassemble the wreckage during inspection for some reason. The broken surface on the fitting seemed dirty so I expect it had been cracked for some time and might have failed. Then again, the dirt could have snug in there during the year our NTSB had it laying on the floor in their hangar.
If I can get permission from the widow, I would like to have some of our more knowledgably friends on this forum to get a look at the video and maybe they can come up with something else. That is if any of them is interested. Any suggestion to whom that should be? Anyone volunteer?
Also I would really like that some of our more knowledgably friends on this forum to look through the video of the accident. (Don’t worry, the end is not caught on video, so no blood ect)
It goes as follows:
I lost a friend a couple of years ago due to partial/blade stall I believe it was.
When spectators were around he usually did some manoeuvres I can't even start to describe. I tolled him over and over again that it was lethal to do so, and explained him the aerodynamic consequences of what he was doing, but I guess he was not clever enough to understand it, or I didn't explain things good enough, or he just didn't care.
Anyway, he usually did these manoeuvres in reasonable calm air, but on that day the wind was about 20- gusting to 30 kts, and I think he forgot all about that in the heat of battle.
- I lost my best friend.
Somebody filmed the accident too.
He was flying a light gyro with a 27' McCutchen rotor (maybe on minimum limit load – in fact I believe it was minimum loaded – turning just under 300 according to late friend)
He was cruising around in about 50' alt doing some "gyro manoeuvres".
The one he specially liked to do was a kind of quick flat spin 360dg turnaround back to same direction with minimum loss of altitude, which is a quick 360dg turnaround without much bank attitude.
I didn’t see the accident myself (fortunately for me) but according to the film at least up to the point where it goes wrong he was doing exactly that, but with in high wind.
At a point he does a low pass in 5' from a lower point, (runway rises) from where the wind was not so strong, pulled up, vent vertically up into the strong wind. When things started to go wrong the ground speed is zero and altitude was about 120'. Nose attitude was high and it seemed that he then tried to turn back downwind, not much with a bank but rather that flat turn. After that the video is pointed towards the ground. A few large slap sounds followed by something that folded together on the ground.
Witness says that he was almost vertically in attitude and seemed to be on the edge to go over the top backwards, but then turned on its side and went straight to the ground, and fluid was coming out during the fall. Our NTSB equivalent here in Denmark found nothing wrong with gyro, and stated it was pilot error.
Though they didn’t describe what went wrong but IMHO and from what I can see and hear from the film I believe he realised he was in deep **** when he found himself vertically or with high nose attitude with no ground speed.
When looking at the film I think he then tried to lower the nose and might have thought that he couldn’t regain control that way and then turned around to gain flight speed again. Why I don’t know, because it is wrong to do that. But when he turned around I believe the violent stick and rudder input lead to blade/partial stall, hence those loud slap sounds. He then lost lift on one side of the rotor for a split second and the gyro went into a 90 dg bank with no airspeed, and continued like this to the ground.
There was no bunt over, wreckage showed no sign of rudder or prop strike.
You can't really see what happened in the end but I do not believe he initially was doing negative G’s on the top of the climb; he’s attitude was not that vertical. As I see it he vas climbing vertical but maybe with a 45dg attitude. At one point I believe I can see the nose wheel and instrument panel. The position of this is almost level but with a 90 angle to the wind (sideways), still no ground speed, so that will be no airspeed too. If he did a violent manoeuvre with the rudder pedals and maybe the stick too to get into downwind he would have experienced the partial stall witch ended up in loss of lift on one side of the rotor. I believe so anyway.
After the loud slabs the rotor sounded like it lost rpm fast, (on that point he would have been sliding sideways into the ground) and the engine then stopped. According to our NTSB the engine stopped during the fall where no positive G’s feed the carb. Propeller was not damaged other than from the fall.
At one point I had the impression that he chopped the throttle before the event or during the event.
Why he didn’t just level the thing and continued forward/down and just rode it out by making a forward decent to the ground beats me.
Maybe the engine failed or he couldn’t lower the nose and decided to do the turn into downwind rather than end up in a tail slide. Who knows, it’s hard to tell. Our NTSB didn’t find anything wrong with engine, but subsequent I found a broken outlet fitting on the electrical fuel pump. When I examined the wreckage the fuel line was still attached to the pump but when I began to disassemble the wreak, it just fell off. Note to this: our NTSB didn’t disassemble the wreckage during inspection for some reason. The broken surface on the fitting seemed dirty so I expect it had been cracked for some time and might have failed. Then again, the dirt could have snug in there during the year our NTSB had it laying on the floor in their hangar.
If I can get permission from the widow, I would like to have some of our more knowledgably friends on this forum to get a look at the video and maybe they can come up with something else. That is if any of them is interested. Any suggestion to whom that should be? Anyone volunteer?