Plane crash video - Not like others I have seen!
Damn! Not meaning to Monday-night quarter back, but the positives that can come out of these things is analyzing and learning from them.
A couple of points- Cross-winds while airborne do not effect airflow into an engine- Slipping to track down a runway would, but maintaining a crab angle until touch-down would stop this.
Closing the throttle on the good engine would have stopped the asymmetry- landing straight ahead- even off-runway- looked a whole lot better than letting the functioning engine carry him into the boneyard.
A couple of points- Cross-winds while airborne do not effect airflow into an engine- Slipping to track down a runway would, but maintaining a crab angle until touch-down would stop this.
Closing the throttle on the good engine would have stopped the asymmetry- landing straight ahead- even off-runway- looked a whole lot better than letting the functioning engine carry him into the boneyard.
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This has has been around a while on YT but still amazing to watch!-
At the end of the day he was just a spectator going along for the ride, he stopped looking at ways to avoid the obstructions, he simply rode the machine to impact where ever that was going to be, very lucky boy!
At the end of the day he was just a spectator going along for the ride, he stopped looking at ways to avoid the obstructions, he simply rode the machine to impact where ever that was going to be, very lucky boy!Last edited by machtuk; 20th Jun 2019 at 07:42.
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Wow, lucky man indeed. And luckily nobody was taking a nap in that mobile home at that time.
This has has been around a while on YT but still amazing to watch!- At the end of the day he was just a spectator going along for the ride, he stopped looking at ways to avoid the obstructions, he simply rode the machine to impact where ever that was going to be, very lucky boy!
At the end of the day he was just a spectator going along for the ride, he stopped looking at ways to avoid the obstructions, he simply rode the machine to impact where ever that was going to be, very lucky boy!
As a gratuitous judgement - is this a case of an aeroplane "designed" by a dilletante rather than an engineer?
The orginal Quickie has a single piston engine driving a prop which gives it both (a) no asymetric thrust case and (b) plenty of propwash over the rudder to give low-speed control authority
This aeroplane appeared to have two small turbojets replacing the piston engine. From what we saw I would guess that:
1) The aircraft needed thrust from both engines to maantain level flight - it could not sustain height on one engine.
2) No enhancement to the rudder to recover the authority lost due to the lack of propwash over the fin/rudder
3) No enhancement to the rudder to ensure sufficient authority to meet an asymetric flight case
As such the whole vehucle was just not airworthy. As an absoolute minimum it would have needed some system to throttle the remaining engine back in the event of one engine failing, so that the ensuing landing was at least straight ahead and under control. But I would have expected to see a much bigger rudder, toe-in on the engines and/or some form of thrust vectoring vane in the engine effluxes to make the whole concept even vaguely airworthy IMHO. My (speculation and gratuitous opinion based on very limited evidence) view is supported by the in-cockpit views which seem to show the pilot pushing right rudder to the stop, but the slip indicator (the string on the canopy) is still showing a huge left side-slip.
As an aeronautical engineer I have always held the view that any twin which can't maintain height on one engine is actually more dangerous than a single, because you get twice the failure rate with no significant failure mitigation.
€0.02 supplied, YMMV etc
PDR
The orginal Quickie has a single piston engine driving a prop which gives it both (a) no asymetric thrust case and (b) plenty of propwash over the rudder to give low-speed control authority
This aeroplane appeared to have two small turbojets replacing the piston engine. From what we saw I would guess that:
1) The aircraft needed thrust from both engines to maantain level flight - it could not sustain height on one engine.
2) No enhancement to the rudder to recover the authority lost due to the lack of propwash over the fin/rudder
3) No enhancement to the rudder to ensure sufficient authority to meet an asymetric flight case
As such the whole vehucle was just not airworthy. As an absoolute minimum it would have needed some system to throttle the remaining engine back in the event of one engine failing, so that the ensuing landing was at least straight ahead and under control. But I would have expected to see a much bigger rudder, toe-in on the engines and/or some form of thrust vectoring vane in the engine effluxes to make the whole concept even vaguely airworthy IMHO. My (speculation and gratuitous opinion based on very limited evidence) view is supported by the in-cockpit views which seem to show the pilot pushing right rudder to the stop, but the slip indicator (the string on the canopy) is still showing a huge left side-slip.
As an aeronautical engineer I have always held the view that any twin which can't maintain height on one engine is actually more dangerous than a single, because you get twice the failure rate with no significant failure mitigation.
€0.02 supplied, YMMV etc
PDR
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Elliot Seguin
Scaled Composites
Elliot Seguin is a Homebuilder, Engineer, and Test pilot. Elliot has worked in aerospace for 10 years from restoration of WWII trainers to spaceships, commercial and non-commercial programs, recips to rocket engines, and antique aircraft to record setting aircraft and race planes. He has some 350 hours flight testing 10 different aircraft (from dropping spacecraft to amphibious electrics), this includes PIC on three first flights. Elliot built two airplanes both Reno racers, one of which is his design. Elliot has helped with 24 world record attempts, setting 6 as pilot. At Burt Rutan's Scaled Composites Elliot is a project engineer, and flight test engineer (200 hrs 6 types).
and
Design, build, and test experimental aircraft.
Working in R&D Experimental Aerospace since 2005. Total time 2400 hours in 76 types, 700 hours testing, on >50 programs, in 14 types. 6 World records, 8 first flights.
Built two airplanes both reno racers, one his new design. At Burt Rutan's Scaled Composites for ten years; project engineer, flight test engineer, test pilot (300 hrs 6 types). 2 years as Lead Test Pilot at Mooney aircraft testing the prototype M10.
Dilettante might be a bit harsh.
I'm embarrassed by my failure to google the guy! So I agree "dilletante" was unjustifiably harsh and I withdraw the comment with apologies.
But can you disagree with the remainder of what I said?
PDR
But can you disagree with the remainder of what I said?
PDR
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I don't know. I would say that he has the training and experience to accurately analyze what went wrong, so I'm happy to rely on his description.
I'm not a ME pilot, but I think that in most of them there is a point in the landing where if you go around and only one engine responds you are going to have big problems.
My understanding of the accident:
Yes a twin should maintain height on one engine. But I know that every twin there is a limit to the bank angle, beyond which it will not maintain height. Other than that, I don't have enough information to make a judgment on the aircraft.
I'm not a ME pilot, but I think that in most of them there is a point in the landing where if you go around and only one engine responds you are going to have big problems.
My understanding of the accident:
- He had a strong crosswind from the right
- As he was about to touch down, a stronger gust lifted the right wing
- He applied power and only the right engine responded
Yes a twin should maintain height on one engine. But I know that every twin there is a limit to the bank angle, beyond which it will not maintain height. Other than that, I don't have enough information to make a judgment on the aircraft.
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There's lots of aircraft I would say that about.
I think the goal was air racing, which is another activity you can count me out of.
But he appears to have enough qualifications to understand the risks and make informed decisions.
Interesting report written up by the pilot:
https://docs.google.com/document/d/1...J-dz-EJVc/edit
I think the goal was air racing, which is another activity you can count me out of.
But he appears to have enough qualifications to understand the risks and make informed decisions.
Interesting report written up by the pilot:
https://docs.google.com/document/d/1...J-dz-EJVc/edit
Nah, the man is clearly no idiot. In fact probably a whole lot smarter and skilled than most who dabble in home built and experimental aircraft.
His mistake was probably choice of airframe to use as a test bed, knowing full well its undesirable handling characteristics. My choice would have been a modified Sonex - which has already successfully flown with a single jet engine and is about the easiest to fly taildragger ever. But he must have had his reasons for that choice.
Because of the engines being located on the fuselage sides of the Quickie, the flame-out may have been due to airflow blanketing in the crosswind.
If it were not for risks taken by test pilots ever since the Wright Brothers, we would still be earth-bound..
His mistake was probably choice of airframe to use as a test bed, knowing full well its undesirable handling characteristics. My choice would have been a modified Sonex - which has already successfully flown with a single jet engine and is about the easiest to fly taildragger ever. But he must have had his reasons for that choice.
Because of the engines being located on the fuselage sides of the Quickie, the flame-out may have been due to airflow blanketing in the crosswind.
If it were not for risks taken by test pilots ever since the Wright Brothers, we would still be earth-bound..
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Very true. Even Lawrence Sperry crashed whilst testing his invention, the first autopilot. Though the fact both Sperry and his female passenger were found naked at the crash site may have also played a part....
Sorry I have to ask........
He complains about the stiff crosswind, fair enough so why didn’t he land on the cross runway instead??????
On the video he clearly flew across the other runway before touchdown and the red windsock indicated into wind for the cross runway????? Was the other runway too short?
Am in missing something here?????
He complains about the stiff crosswind, fair enough so why didn’t he land on the cross runway instead??????
On the video he clearly flew across the other runway before touchdown and the red windsock indicated into wind for the cross runway????? Was the other runway too short?
Am in missing something here?????
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To me it looks like he let his airspeed drop to the point where the residual asymmetric thrust couldn't sustain directional stability, perhaps he then tried to increase the power which at that deteriorated airspeed all it did was roll the aircraft even more. Lucky man, he obviously won't be doing that again.
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Bert already solved the asymmetric issue - in an unusual way:
https://www.wired.com/2011/07/burt-r...ugh-asymmetry/
https://www.wired.com/2011/07/burt-r...ugh-asymmetry/
Why would the crosswind have caused intake blanketing? The aeroplane clearly didn't have crossed controls at the time of the flame-out (look at the string slip-indicator) and, as one would hope we all know, a cross wind wouldn't change the direction of the airflow over the aeroplane in the air except as a (very) brief transient gust response. If the engines are too fragile to take that brief gust then the aeroplane would be a death trap anyway, because it wouldn't be able to survive even mild turbulence.
Reading the interweb I'm let to believe that the engines were Czech PBS TJ-40 turbojets - simple turbines based on scaled-up model aeroplane concepts intended for UAV applications. These engines have centrifugal compressors and so are pretty "robust" when it comes to airflow. They don't suffer compressor stall /surge symptoms to anything like the same extent as axial-flow compressors, and need pretty huge airflow changes to upset them. There had been a history of issues with one of the engines (even seen on the videos on the day of the flight) and my personal view is that this blarney about crosswinds may be trying to stop people looking too closely at whether the aeroplane was fit for flight with a troublesome engine.
£0.00007 supplied,
PDR
Reading the interweb I'm let to believe that the engines were Czech PBS TJ-40 turbojets - simple turbines based on scaled-up model aeroplane concepts intended for UAV applications. These engines have centrifugal compressors and so are pretty "robust" when it comes to airflow. They don't suffer compressor stall /surge symptoms to anything like the same extent as axial-flow compressors, and need pretty huge airflow changes to upset them. There had been a history of issues with one of the engines (even seen on the videos on the day of the flight) and my personal view is that this blarney about crosswinds may be trying to stop people looking too closely at whether the aeroplane was fit for flight with a troublesome engine.
£0.00007 supplied,
PDR
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Having just a little experience with small microjets (a week of test flying a single with 42kg thrust so bigger than those on the quickie, my comment is they need heaps of speed to create much thrust.
it is exponential! After the aborted landing the speed was too low to climb out on one, They need speed, very little static thrust.
it is exponential! After the aborted landing the speed was too low to climb out on one, They need speed, very little static thrust.
