Seeing the nekkid version is that much more impressive. His glassing skills may not have been as good as his woodworking ones.
Data from the flight data recorder (FDR) showed that the events leading into the crash began at 9:15:36, when the aircraft hit wake turbulence from the JAL flight just in front of it. The first officer attempted to stabilize the aircraft with alternating aggressive rudder inputs from left to right. This continued for at least 20 seconds, until 9:15:56, when the stress of the first officer's repeated rudder movements caused the lugs that attached the vertical stabilizer and rudder to fail. The stabilizer separated from the aircraft and fell into Jamaica Bay, about one mile north of the main wreckage site. Eight seconds later, the stall warning sounded on the cockpit voice recorder. The FDR cut off at 9:16:00, and the CVR (cockpit voice recorder) cut off at 9:16:15.
At the moment the stabilizer separated from the aircraft, the plane pitched downwards, headed straight for Belle Harbor. As the pilots struggled to control the aircraft, it went into a flat spin. The resulting aerodynamic loads sheared both engines from the aircraft seconds before impact. The engines landed several blocks north and east of the main wreckage site.
The vertical stabilizer is connected to the fuselage with six attaching points. Each point has two sets of attachment lugs, one made of composite material, another of aluminum, all connected by a titanium bolt; damage analysis showed that the bolts and aluminum lugs were intact, but not the composite lugs.
That's what I was thinking, too, with vertical stabilizer damage being hidden by glassing or whatever he used. It was flown a number of times prior to the breakup.It makes me wonder if there wasn't some prior damage on this plane as well.
If you're gonna fly, you're gonna crash.
EDIT: Forgot to mention that he did the same knife-edge maneuver in this earlier flight that led to destruction in the later one.
Hmm, looked at it again a few more times, can't look frame by frame but was able to jump back about 1 second and see it cycle over and over. One frame I sometimes stopped the recycle at looks like the rudder/tail starts to break in one piece but then another frame I sometimes hit after that, it "explodes" into a bunch of pieces. So it does not seem to be just the base mount failing, it's shocking that the whole vertical tail would shred like that.
I didn't do any extensive Google translations of the German forum discussing the plane's design and construction, but I'll bet it was more of a best guest from experience sort of structural design than one submitted to computer structural analysis.If you set the playback speed to .25 and the def to 1080P you can see the rudder to the left then the vertical stabilizer sheers at the base and when it get tossed into the air behind the wings it breaks apart a bit more but if you follow it there appear to be a lot more splinters than what is actually left over.
My take on this is that the flight profile surpassed the structural limits of the plane, or at least the base of the vertical stabilizer.
I get that the designer and builder made some choices when it comes to weight vs. strength in order to maximize the performance. However obviously a bit more reinforcement in this area was required. That is if you wanted to fly it they way they were.
[video]https://youtu.be/8yf_QTbDeWM?t=109[/video]
Another disadvantage of composite structures is that it is impossible to detect damage other than by destructive testing. They're making strides in this area, but it's still much easier to detect cracks and other problems in metal. Not so much when the damage is 50 composite layers deep.
The vertical stabilizer on that Airbus had been damaged years earlier in a hard landing incident and a contributing factor in that accident.
To my knowledge, that would be allowed. The weight limit for R/C aircraft in the US is 55 lbs. Beyond that, they're not in the special category of "model aircraft," a category that used to exempt them from any FAA intervention.I am curious as to what aero loads were on the verticle stab before it went. I'm thinking that 3 aluminum tubes would have given it enough structural stiffness to keep it on the airframe. But I don't know if that's allowed for R/C aircraft.
Greg
The only experience I've had has been with EPO foam kits with carbon fiber tubing spars and brushless electric motors. I've never done anything stick built and would die inside if I'd ever build anything remotely like that plane and have it smashed to bits... which is why I did the foamie thing. Love to watch other people do incredible stuff and risk flying it, though.Aluminum is allowed in construction; before carbon fiber became mainstream most wing tubes were aluminum. I know I've even seen at least one design that was built entirely of aluminum. Aluminum spinners are still common, and of course the engines are aluminum.
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