Flight test of the Jetpod
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If you look at the design of the aircraft, you can clearly see that the main gear are way aft of the center of lift.
Because of that configuration, the excessive downward force required by the elevator to cause the plane to raise the nose with the pivot point being the (too far aft) main gear would guarantee pitch-up once the wing generated lift and the "pivot point" changed from the main gear to the center of lift.
Because of that configuration, the excessive downward force required by the elevator to cause the plane to raise the nose with the pivot point being the (too far aft) main gear would guarantee pitch-up once the wing generated lift and the "pivot point" changed from the main gear to the center of lift.
This was the situation with the crash, on its first flight, of an experimental delta-wing aircraft (Flint, Michigan, almost 50 years ago). It had a pusher prop, with MLG well aft to give ground clearance. It had a very long takeoff roll, then a rapid pitchup and stall.
"What a pair of armchair investigators you two are. From nothing more than some press releases and cartoon photos/animations you have managed to figure out what most likely happened in this tragic accident and are even able to comment on the character of Mike Dacre without knowing who he was or his aviation background.
Perhaps Walt Disney Productions could use you both to investigate some of Mickey Mouse's mishaps.
Might I suggest that if you crave recognition as anything serious, you write to AVCEN and request the facts. If they feel your expertise is of value then I'm sure they will give you the facts you deserve. Until you have such facts on which to base your amazing deductions, I would suggest you scribble your notes on your next square of toilet paper, just before its function is fulfilled.
Nil further.
Tam Macklin"
Spot on Mr Macklin Sir.
Perhaps Walt Disney Productions could use you both to investigate some of Mickey Mouse's mishaps.
Might I suggest that if you crave recognition as anything serious, you write to AVCEN and request the facts. If they feel your expertise is of value then I'm sure they will give you the facts you deserve. Until you have such facts on which to base your amazing deductions, I would suggest you scribble your notes on your next square of toilet paper, just before its function is fulfilled.
Nil further.
Tam Macklin"
Spot on Mr Macklin Sir.
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From this picture, which I am told it is the Jetpod being assembled on site in the days before the crash, it would appear to bear only a passing resembalance to the cartoons. It was also significantly bigger than than the artists impression.
Its design and finish would imply that a significant amount of $$$ had been spent on it.
As for Malaysian press reports, they are slightly less reliable than most of the information found on Pprune.
............................how do I insert the picture here without posting it to another website first ??????????????????????????
Its design and finish would imply that a significant amount of $$$ had been spent on it.
As for Malaysian press reports, they are slightly less reliable than most of the information found on Pprune.
............................how do I insert the picture here without posting it to another website first ??????????????????????????
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If anyone wants to post the picture, PM me and I will send it to an email address. Bear in mind I didn't take it. It was sent to me, and I am told it was the Jetpod. The picture appears to be just that.
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First off, thank you Mr. Macklin and Mostafa for keeping this thread alive.
Secondly, I understand that I posted a lot of information, but if you look at the YouTube "teaser" from last year, with the child visiting the hangar shot from last year, and where they'd covered the unfinished engines/cockpit, you'll indeed see that the design they were working on was apparently more of a straight-wing configuration, with the landing gear directly under the wing (and possibly on something that worked as a smaller, second airfoil).
Third, Macklin is right. I am an armchair investigator. I heard a story about "another flying car nutcase" and went to investigate, using the means at my disposal to gather information in a matter of hours. What I found, and what I tried to communicate, was that the "Jetpod vision" was in engineering terms pragmatic -- I mean, unlike the "flying car" crowd, Dacre had something that would fly, and would at least come close to his goals -- and in social, political and economic terms challenging, if not outrageous -- change the world to match the vision, and do so on a startup budget. In other words, this isn't what it's being portrayed as: a nutcase doing something stupid. There's a vision, coherent, if apparently unworkable; there's a plan; and there's risks that had to be taken, the biggest one of which was that the whole thing would somehow work.
Call it Disney if you like. The Greeks had Icarus. Some of us have Werner Herzog. I never met the guy, and am worse off for it. I look at the record I can find and wish I were in a situation to find out truly what his story was. In my experience, the greatest people I've met have been tragic characters.
But all of that is beside the point. At this point, we know very little about what happened (unless someone deigns to reveal their personal knowledge), and we're not likely to learn anything.
Secondly, I understand that I posted a lot of information, but if you look at the YouTube "teaser" from last year, with the child visiting the hangar shot from last year, and where they'd covered the unfinished engines/cockpit, you'll indeed see that the design they were working on was apparently more of a straight-wing configuration, with the landing gear directly under the wing (and possibly on something that worked as a smaller, second airfoil).
Third, Macklin is right. I am an armchair investigator. I heard a story about "another flying car nutcase" and went to investigate, using the means at my disposal to gather information in a matter of hours. What I found, and what I tried to communicate, was that the "Jetpod vision" was in engineering terms pragmatic -- I mean, unlike the "flying car" crowd, Dacre had something that would fly, and would at least come close to his goals -- and in social, political and economic terms challenging, if not outrageous -- change the world to match the vision, and do so on a startup budget. In other words, this isn't what it's being portrayed as: a nutcase doing something stupid. There's a vision, coherent, if apparently unworkable; there's a plan; and there's risks that had to be taken, the biggest one of which was that the whole thing would somehow work.
Call it Disney if you like. The Greeks had Icarus. Some of us have Werner Herzog. I never met the guy, and am worse off for it. I look at the record I can find and wish I were in a situation to find out truly what his story was. In my experience, the greatest people I've met have been tragic characters.
But all of that is beside the point. At this point, we know very little about what happened (unless someone deigns to reveal their personal knowledge), and we're not likely to learn anything.
Third, Macklin is right. I am an armchair investigator. I heard a story about "another flying car nutcase" and went to investigate, using the means at my disposal to gather information in a matter of hours.
I look at the record I can find and wish I were in a situation to find out truly what his story was.
write to AVCEN and request the facts. If they feel your expertise is of value then I'm sure they will give you the facts you deserve
Notwithstanding that this is a rumour network, can I suggest some benefit of the doubt is given in this case until more facts are known?
How do you know that he had not approached this first flight in a thoroughly professional and incremental manner?
How do you know that he got airborne 'inadvertently'?
How do you know that he did not seek advice from professionals?
It certainly does not seem from your post that you know the answers to these questions, so why assume the worst?
How do you know that he had not approached this first flight in a thoroughly professional and incremental manner?
How do you know that he got airborne 'inadvertently'?
How do you know that he did not seek advice from professionals?
It certainly does not seem from your post that you know the answers to these questions, so why assume the worst?
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Notwithstanding that this is a rumour network, can I suggest some benefit of the doubt is given in this case until more facts are known?
How do you know that he had not approached this first flight in a thoroughly professional and incremental manner?
How do you know that he got airborne 'inadvertently'?
How do you know that he did not seek advice from professionals?
It certainly does not seem from your post that you know the answers to these questions, so why assume the worst?
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Genghis.
If you update the "Protecting the Flight Test Programme" Paper read at the SETP/SFTE Flight Test Workshop at RAeS a couple of years ago, it may be appropriate to use this project as an example.
It is a pity that the Proceedings of these Workshops are not published. Had Mr Dacre been aware of such advice, the outcome of the flight test programme might have been different.
Kind Regards.
If you update the "Protecting the Flight Test Programme" Paper read at the SETP/SFTE Flight Test Workshop at RAeS a couple of years ago, it may be appropriate to use this project as an example.
It is a pity that the Proceedings of these Workshops are not published. Had Mr Dacre been aware of such advice, the outcome of the flight test programme might have been different.
Kind Regards.
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Long takeoff run and a terminal pitch-up right from rotation.
I think this video supports my armchair investigation......which was based on basic physics as well as not believing the reports that the pitch up started AFTER it climbed 200 meters.
The F7U cutlass had main landing gear that would move forward to bring the pivot point closer to the center of lift because of the same issues I mentioned earlier in this thread concerning the jetpod.
f7u-1
My dad flew the F7U a few times and was very glad then it was dropped from the navy inventory..........of course he also turned down a blue angel's gig.
I think this video supports my armchair investigation......which was based on basic physics as well as not believing the reports that the pitch up started AFTER it climbed 200 meters.
The F7U cutlass had main landing gear that would move forward to bring the pivot point closer to the center of lift because of the same issues I mentioned earlier in this thread concerning the jetpod.
f7u-1
My dad flew the F7U a few times and was very glad then it was dropped from the navy inventory..........of course he also turned down a blue angel's gig.
Last edited by IcePaq; 23rd Mar 2011 at 00:57.
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There seemed to be quite a crowd there, so I suppose it is no surprise to find this other clip.
The comment in this cellphone video indicates that it was filmed by one of those involved in the construction of the prototype, judging from his reaction I wonder whether the takeoff was really unintentional. I would think not.
Strange story anyway.
The comment in this cellphone video indicates that it was filmed by one of those involved in the construction of the prototype, judging from his reaction I wonder whether the takeoff was really unintentional. I would think not.
Strange story anyway.
Moderator
I know nothing more about this event than what I have seen posted here.
I value such videos, as a learning tool, that I prevent errors in the test flying I do. Part of the "learn from other's mistakes, you'll not live long enough to make them all yourself" spirit.
The video reminds me of the planning I have stuck by for those occasions where I have taken off in a "suspect" aircraft (I have never done any first flights of a new design).
I have at those "suspect" occasions, planned an aborted takeoff, and committed that no matter how well it seemed to fly, I would land back, for another go. Watching the video, it appears to me that there was a brief period, where a land back would have worked out. It would appear, that as a land back was not done, either it was not planned, or or it was, and the plan was not followed.
I once maintenance test flew a Cessna 206 which displayed tendancies similar, though obvioulsy less dramatic, to those seen on the video. After a very scary, and very short circuit, I reminded myself that even production aircraft should not be taken for granted, particularly following maintenance. There was no excuse for my not being prepared to land back on that flight. I should have been treating this aircraft as "suspect", but instead took it for granted, as I had flown it the previous month, and it was fine. I presume that all test flights should at least include a consideration of the need for a possible aboted takeoff.
I have no comment on the merits of the subject aircraft, but it appears to me that a test program stage, which might have increased the safety of the test flying, did not occur.
Perhaps more objective information, from which we can learn, will come to light in this unfortunate case.
I value such videos, as a learning tool, that I prevent errors in the test flying I do. Part of the "learn from other's mistakes, you'll not live long enough to make them all yourself" spirit.
The video reminds me of the planning I have stuck by for those occasions where I have taken off in a "suspect" aircraft (I have never done any first flights of a new design).
I have at those "suspect" occasions, planned an aborted takeoff, and committed that no matter how well it seemed to fly, I would land back, for another go. Watching the video, it appears to me that there was a brief period, where a land back would have worked out. It would appear, that as a land back was not done, either it was not planned, or or it was, and the plan was not followed.
I once maintenance test flew a Cessna 206 which displayed tendancies similar, though obvioulsy less dramatic, to those seen on the video. After a very scary, and very short circuit, I reminded myself that even production aircraft should not be taken for granted, particularly following maintenance. There was no excuse for my not being prepared to land back on that flight. I should have been treating this aircraft as "suspect", but instead took it for granted, as I had flown it the previous month, and it was fine. I presume that all test flights should at least include a consideration of the need for a possible aboted takeoff.
I have no comment on the merits of the subject aircraft, but it appears to me that a test program stage, which might have increased the safety of the test flying, did not occur.
Perhaps more objective information, from which we can learn, will come to light in this unfortunate case.
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The wing design is really elegant, though I think the aft fuselage looks rather clunky and a great source of base-drag. Was there really any reason they used such an odd shape? From the little I know, it looks like the could have lengthened it into a V-shape and could have still managed to include an aft-entry.
Last edited by Jane-DoH; 3rd Apr 2011 at 05:25.
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Was there any reason why they required vertical thrusting engines to allow the short takeoff distance? Why didn't they use some kind of blown-flap system, perhaps something more like Boeing's CESTOL concept?
