Posted on 09/23/2011 1:08:27 PM PDT by george76
In their first official report on the Reno air race crash earlier this month, federal accident investigators on Friday noted evidence that a small piece of the plane's tail separated shortly before the crash.
But investigators did not say whether the loss of the plane's "trim tab" was the cause or the result of the plane's violent maneuvering before it crashed into the ground, killing 11 and injuring 74.
The National Transportation Safety Board preliminary report was a straightforward recitation of facts already known in the Sept. 16 crash at Reno Stead Airport in Reno, Nev. Investigators said it typically takes about a year before the safety board rules on the probable cause of an incident.
The report notes that the modified P-51D Mustang had completed several laps and was in a steep left turn toward the home pylon when, according to photographic evidence, the airplane suddenly banked momentarily to the left before banking to the right, turning away from the race course, and pitching into a steep dive.
Witnesses reported that a piece of the airframe separated during these maneuvers, a fact confirmed by the photographic evidence, the Safety Board said.
(Excerpt) Read more at krcrtv.com ...
A trim tab is not the tail...
Thought they were talking about Janet Reno.
That’s what hep pens when you are locked in a data center all day.
Idiot reporting.
Good thing they had that video to tell them that information . . .
It is amazing how the media distorts any headline involving an aviation accident/incident. The whole tail didn’t break off. The small trim tab did but that was probably the cause for the resulting extreme pitch up, probable G-LOC and devastating plunge to the ground at near vertical. May all the victims RIP and those with injuries physical and mental recover as quickly as possible.
I know it is an unfair and worthless comparison, but I keep thinking of another WWII era plane, the B-17 flying home shot “all to hell” many times. Missing pieces bigger than a P-51 wing.
The airplane rolling first one way and then the other indicates a high speed stall.
A stall is caused by the wing losing lift because the air flow separates from the top of the wing. It is a matter of angle, and not speed. That is exactly how an airplane does a snap roll.
Not picking, but seems like a good spot. Gonna ask you - and all others - “how does a conventional aircraft’s tailplane actually work ? “ I.e. describe the primary aerodynamic forces at work.
I’ll get back to y’all later. >PS
It’s like a fish’s tail: It waggles and propels the airpl...hehe, OK, nevermind.
A trim tab is not the tail...
“how does a conventional aircraft’s tailplane actually work ?”
The horizontal stabliziers (the little “wings”) help the airplane resist pitch, which is an up and down rotation about a side to side axis.
The rudder is a movable panel at the rear of the tail, and it lets the pilot adjust the yaw of the airplane relative to the airstream. Note that this isn’t really used to steer, which is done instead by banking the aircraft to one side and pulling the nose up somewhat.
The elevators are movable panels at the rear edges of the horizontal stabilizers, and are moved to adjust the angle of attack (how much the nose is pointed up or down relative to the airstream).
More or less.
Do the "trim tabs" help the pilot fine-tune this function?
“The elevators are movable panels at the rear edges of the horizontal stabilizers, and are moved to adjust the angle of attack
Do the “trim tabs” help the pilot fine-tune this function?
If this trim tab were to break off, it would be like a sudden input pulling back on the stick, possibly beyond the physical limits of the airframe or pilot.
Interesting answers !
Point is, in conventionally-configured aircraft (like -51 platform) the “horizontal stabilizer” (to give its correct name ) “flies down” ! That is it applies force in 180’ opposition to the aerodynamic forces from the main plain, (i.e. wing) ! Suddenly remove this force and the aircraft “pitches over “ i.e. noses “down” from the pilot’s viewpoint.
IOW, some conclusions/suppositions I’ve read, here and elswhere, claiming the “tail failure caused the pitch up” are, IMO, pretty much false to known fact. Loss of the trim tab might - indeed probably - increased stick pitch forces but not - IMNSHO - to the point of causing a LOC. (I know I’d configure the aircraft W/B and consummable loads consumption CG changes to create/maintain a neutral or aft limit CG in order to minimize “trim drag”.)
Want a real world description of what a “tail loss stall” is ? Read Bob Cardenas’ description of his first stall in the first Northrup flying wing ! It had no tail ! >PS
I wouldn’t - at this point - disagree ! It also “fits” into suppositions - supported by photos - of a seat failure that could have resulted in a “everything into a corner” stick movement by a pilot holding desperately to his only support ! (Never forget the “simian grasping reflex” ! Its with us from birth to death ! >PS
The wings (obviously) provide lift at approx. the aircraft's center of gravity. The horizonal stabilizer does just that -- stabilizes the aircraft's pitch. The elevators provide the up or down movement to the tailplane to cause the nose (and angle of attack) to go up or down, according to the pilot's wishes. i.e., the pilot pulls back the stick, the elevators move up, pushing the tail down which rotates the nose up. (pitch rotates about the center of gravity)
A small, but important, thing .
[Zm] “....(pitch rotates about the center of gravity)....”
The pitch axis is the center of pressure, (i.e. “lift”)! I’ve listened to old Wofgang Langwichie, (sp ? ) too many times expounding on this subject to have forgotten it ! [grin] Seriously, Wolfgang is the author of the seminal aviation work “Stick and Rudder”. He was also a habitue of the same airport cafe back in my “airport bum” days !
FWIW Max Conrad used to load his Piper Commanche outside the aft CG limit for his epic distance flights to reduce “trim drag”.
What does any of this have to do with events at Reno ? I suspect damn little ! [grin] >PS
As for the Reno crash, I still can't believe a lost trim tab by itself would cause a 10-g zoom and the tragedy that followed...But then I've never flown a P-51 500 mph either! ;-)
During my “airport bum” years one, Sky Manor in Pittstown, NJ was a mecca for major “movers and shakers” in the aviation world. In its cafe, along with Wolgang, you could chat with Leighton and Dick Collins, Bob Buck, Marvin Cole, Jim Bede, Bob Hoover, Leo Laudenschlager and Chet Volk are among notables and pioneers I readily recall.
I always marveled at how many from the,(old and new), frontiers of aviation made their way to this little outpost over the years I hung around ! But then, western NJ/Eastern PA was a mecca for pilots in those times ! >PS
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.