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PS.GG was reported at 495 mph; that equates to M.645 at 5500ft at an assumed *T of 20*C; M.75 would be 579 mph in the same conditions. Shock strength and location are dependent on Mach number and CL. You can see what Mach buffet looks like from the tufts and the wake rake/camera vibrating. Mach buffet is just a stall, but at substantially higher q's so the loads are higher. |
More fundraising for the victims of the crash going on at the moment....
loadedtv - live streaming video powered by Livestream The goal is $1,000,000 - nothing ventured, nothing gained :ok: |
Nauseating
You are taking an airplane designed to kill Germans with 1940 engines. Because it's a cool airplane, let's race it by chopping it to s--t and tearing off its radiator and on and on.. stupid and hateful.
The pilot and his crew blasted several people into atoms with their insane modifications of this airplane, and their old man steward who dyed his gray hair brown, because the idea of graceful aging was anathema to his narcissist being, is the main culprit. This entire episode is hateful to aviation - the butchering of a great airplane, the narcissism of the pilot, the tragedy of the annihilated and their families. For what? A stupid race that means nothing. A way to convert money into noise. -drl |
This entire episode is hateful to aviation - the butchering of a great airplane, the narcissism of the pilot, the tragedy of the annihilated and their families. For what? A stupid race that means nothing. A way to convert money into noise. |
Video Frame Grabs
I've grabbed a bunch of video frames from the best video I've seen of the GG initial roll left. These have been processed by increasing brightness and contrast, and cropping to show only the aircraft. They seem to show the port elevator deflected up. The elevators are not visible at the initiation of the problem but soon become visible as the g turns the aircraft. Compare the thickness of the stabilizer-elevator combination above and below the fuselage to see this.
http://home.comcast.net/~shademaker/GG11.jpghttp://home.comcast.net/~shademaker/GG12.jpghttp://home.comcast.net/~shademaker/GG13.jpghttp://home.comcast.net/~shademaker/GG14.jpg The only way that there would be significant elevator split is if the elevator torque tube system failed. The third and fourth pictures appear to be showing the port elevator deflected upward. The second picture is not clear enough, and the attitude in the first picture puts the elevator too close to the wing to be sure of anything. Subsequent pictures appear to show the elevators back in balance. One would assume that if the torque tube simply failed at either the port or starboard side, that the port elevator would be deflected downward by a force twice what was needed from the tab, and the starboard elevator would move upward due to the loss of down torque from the other side. Instead we appear to see the opposite effect, so perhaps the likely shearing of the torque tube is indeed due to a failure of the tab system. The Ghost should have had an elevator bobweight in the system to increase stick force per g. If so, the mass of the elevator actuation system would act to dampen torsional shock loads being sent from the port elevator, so the torque on the inboard side of the port elevator could be higher than the torque on the inboard side of the starboard elevator. The pictures of the trim tab separating indicate that the entire tab was not lost, but that it instead detached at the inboard end and broke off at the center support. The separation at the inboard tab attachment may be due to flutter from some other initial failure (such as the linkage), or it may be the actual initiating event. |
Just thumbing through one of, if not the best book, on aerodynamics written and found this. (Aerodynamics for Naval Aviators)
PILOT INDUCED OSCILLATIONS The pilot may purposely induce various motions to the aircraft by the action of the controls. In addition, certain undesirable motions may occur due to inadvertent action on the controls. The most important condition exists with the short period longitudinal motion of the airplane where pilot-control system response lag can produce an unstable oscillation. The coupling possible in the pilot—control system-aircraft combination is most certainly capable of producing damaging flight loads and loss of control of the aircraft. When the normal human response lag and control system lag are coupled with the airplane motion, inadvertent control reactions by the pilot may furnish a negative damping to the oscillatory motion and dynamic instability exists. Since the short period motion is of relatively high frequency, the amplitude of the pitching oscillation can reach dangerous proportions in an unbelievably short time. When the pilot induced oscillation is encountered, the most effective solution is an immediate release of the controls. Any attempt to forcibly damp the oscillation simply continues the excitation and amplifies the oscillation. Freeing the controls removes the unstable (but inadvertent) excitation and allows the airplane to recover by virtue of its inherent dynamic stability. The pilot induced oscillation is most likely under certain conditions. Most obvious is the case of the pilot unfamiliar with the "feel" of the airplane and likely to over control or have excessive response lag. High speed flight at low altitude (high q) is most likely to provide low stick-force gradients and periods of oscillation which coincide with the pilot- control system response lag. Also, the high q flight condition provides the aerodynamic capability for failing flight loads during the oscillation. If a pilot induced oscillation is encountered the pilot must rely on the inherent dynamic stability of the aircraft and immediately release the controls. If the unstable excitation is continued, dangerous oscillation amplitudes will develop in a very short time. |
A way to convert money into noise. Oh yeah, and give rise to many interesting and informative discussions (both in success, and unfortunate failure), some of which are intruded by persons offering no value or interest whatsoever, just foul drivel! I'm sure there is great sadness with many people about this. Words like "kill" and "hateful" do nothing to help anyone get past this sadness. Perhaps deSitter should only type into computers which are not operating at the time.... On the positive side, I'm learning lots about control and stability! Thanks everyone else...... |
their old man steward who dyed his gray hair brown,...... is the main culprit |
Machinbird. I notice two additional artifacts: One, the port stabiliser makes a different line with the TE of the wing than does the Stbd. This shows a torsion to the right, out of rig with the Long axis? Also, one can see quite clearly the outline of the main spar in the wing. It is outlined by the skin taking form around it in reaction to the immense g.
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the port stabiliser makes a different line with the TE of the wing than does the Stbd. Take powerpoint and mark up the picture you think this is most obvious. Be sure you are not looking along the trailing edge line of the elevators. You have to look at the leading edge of the stabilizer to show actual tail twist relative to the wing, probably by lining up the corners of the stabilizer LE tips. If the port elevator deflected as much as I suspect it did, it may account for the left roll at the beginning. |
Hi Machinbird. It is most pronounced in the second frame. Line up the port stab with the dihedral of the (left) wing. Do the same with the stbd stab and note what I think is about 7-10 degrees off rig. Leftward. A straightedge makes it look sharper. The first frame shows it also with the Port Stab tip proud of the wing line; the stabd is blended in.
Rotate the frame 90 degrees, it is of course easier to see that way. The fourth frame would be about where I see a start of the recoil of the tail feathers back to stabd in slomo. If one was patient, and could orient the PITCH angle with the video, and index it with the time between frames, a rough value of G could be had? Do you notice the Spar shadow spanwise? These are not inconsequential interruptions of airframe contour/rigging. Imagine trying to fly or recover with the tail out of rig several degrees from the fuselage and wings. Or don't, gives me the willies........:ok: |
Lyman, I think you are being fooled by asymmetric elevator deflection into perceiving the stabilizer is twisted.
On the first picture, you cannot make out any stabilizer landmarks, only elevator. On the second picture, the light gap between the stabilizer and wing is symmetric although extremely small. On the third and fourth frames, the light gap appears symmetric. Keep in mind we are dealing with very few pixels, and if you blow the pictures up to gain accuracy, the surfaces become 'mushy' and ill-defined. Furthermore the display appears to begin shading in the next frame over a short interval and you have the beginning of the next image ghosting next to the current ones. This ghost effect isn't all bad since the degree of displacement of the ghost is an indication of rate of position change. |
From this video;
Reno Crash Live 2011-09-16 - YouTube If anybody can work out pitch rate for the first 45 degrees and the last 45 degrees of pitch, we can work out g. Might need a stop watch after correlating to the video clock. I got 90 degrees in 2 seconds but that's rounded from the video. Even then, works out to 16-20 g's average. Makes sense that Voodoo pulled 10g with one tab intact that GG would pull 20 g's with the only trimming tab displaced. If we can get tenths of a second, the number will be more accurate. Torquing across the elevators due to the one tab is still bothersome, and a failure mode could be either elevator twisted loose from the torque tube exciting the 180 degrees out of phase plunging flutter of the horizontal that might be seen in the video. This would over strain the tab actuator rod causing the tab to flutter/fail allowing a higher g pitch up than Voodoo. |
From a colleague in the US
Subject: Fwd: [GSWarbirds] Reno Incident So here is the scoop I got over the weekend. Turns out one of the mechanics at the airport was on the ground team for one of the unlimited racers and had the spot in the pits right next to the lost plane. The ground team had a real time data feed from the airplane. Looks like the plane had a high speed flutter on the port elevator trim tab. The pilot reported a vibration. · The trim tab came off in flight which caused the entire tail group to twist. There are trim tabs on both sides and the asymmetry caused a huge over load. Also high power settings require a lot of nose down trim to stay level, the loss of the trim tab could not be overcome by the pilot. The twist in the tail group made the tendency to nose up even greater and caused damage to the internal structure in the tail – looking at the pictures you will see the tail wheel is down and the gear doors are gone – stuff was coming apart in there. · The twist and the loss of trim caused a near instantaneous 11G pull up – this probably incapacitated the 73 year old pilot and may even have broken the mounts on the pilot seat. Note you cannot see him in the cockpit. The 11G pull also caused a brief loss of engine power from low fuel pressure – the pump could not overcome 11G. · After the 11G pull up the airplane unloaded in steep climb – with the G off the engine regained power. · Without the pilot to overcome it the airplane torque rolled causing a split S into the ground. · The data showed that the airplane was pulling 105 inches on manifold pressure on impact. The "normal" race boost would be 60 to 70. So the airplane was going just under 500MPH when it hit so no fire just total disintegration. |
Internet article of Matt Jackson denying previous internet article.
What Didn’t Cause the Reno Air Race Crash | Jeff Wise |
"So here is the scoop I got over the weekend. Turns out one of the
mechanics at the airport was on the ground team for one of the unlimited racers and had the spot in the pits right next to the lost plane. The ground team had a real time data feed from the airplane." Scoop of what? :8 Sorry but my daughter brought her iPad home and I had to try it out somewhere. No disrespect intended. I've been following this thread since the accident and have learned a lot. The dynamics of racing, both human and Physical, are something of which I was previously unaware. CC you've shown me what I should have been studying 35 years ago. |
Another frame showing bent port HS due to plunging flutter if the frame isn't an optical illusion. The counterweights out at the tips would exacerbate this mode from the elevator pitch flutter, and/or an elevator twisting off the torque tube. The left one looks a little bent too.
http://www.wire-edm.com/temp/1.jpg |
Machinbird. You are saying that asymmetric elevator has me fooled into seeing the stabilizer is twisted? What else could it be doing? Any out of consonant deflection by the two elevators would torque the Stabs radically. At that velocity? It would twist the airframe, I don't see ailerons capable of rolling that a/c that rapidly, the roll was uncommanded, surely.
I do see the twist of the tail, and I see the a/c recovering from it in the video. The recoil shakes the image of the a/c in the video, do you not see that? There is distortion of the image throughout this sequence, the object was in the midst of a violent airborne prang. imo. Cub: Yes, The left HS has a pronounced anhedral in that image. That appears to be Mach's #2 image in his four sequence panel, above. If I may, I'd suggest I see the ailerons commanding a right roll in that image, and we know it was rolling left. Did the tab problem interrupt a right roll? |
Ailerons Frame 2 to 3
Frame 2 appears to me to show the ailerons commanding a right roll as well, but because the plane had moved some distance between 2 and 3, the camera angle, including a possible roll off vertical of the focal plane itself, might have occurred within that interval. Spherical aberration in the lens might also be coming into play. Therefore, I wouldn't bet a whole lot of money that the plane is really banked more steeply left in Frame 3 than it is in frame 2. I'd want to know much more about the camera and lens before opining on what frame intervals show. You might even need multiple angles to be sure; though telemetry could well render optics issues moot at the end of the investigation.
I agree that there appears to be significantly more downward force on the left side HS than on the right in Frame 2; so his initial roll rate to the right could have been slower than he expected. Was he really going for horizontal wings, which, if still conscious at the time, he would have known would send him straight over the crowd, or is it possibly over control or an unpredicted snap to the right that put him there? |
I think the right elevator may have failed at its mount to the bellcrank before the tab failed. If it retreated upward, this leaves the left elevator to command the current NOSE DOWN. It cannot, on its own, so it loses the trim tab, and both elevators migrate to emphatic NOSE UP, though asymmetrically. I'd like to be able to say Jimmy immediately pushed and rolled right, but I think he was already incapacitated. I think with maximum tail section deflection down, and twisted port down, the a/c violently reacted, and pitched back on its own to ND and level, carrying right aileron throughout the double fail. The tail section reverted to close to original alignment, but, carrying some NOSE UP bias, the a/c climbed, lost power, and ballistic roll, inversion, and power recovery followed.
It's hard to say. I am astonished with the violence of the Pitch Up with wings vertical, and believe this is the point of maximum airframe load. The fact remains that NTSB have it all. All of it. They will have the real deal in time enough. Without risk, and bold experiment, life would not be full. I'll be at RENO next year; maybe I'll get to meet up with Clipped Cub. |
Been looking for information on whether trim tabs should be mass balanced,but could not find anything conclusive; however if one `googles `SAWE`Paper3020`,by Space Electronics,there is good stuff about mass balance and the effects of `flutter`.
I have had aileron flutter on an aircraft,coincidentally an 80% scale Mustang;on completion of some testing for `G` limits and `rolling `g`pull-outs.It started at about 160kts,as I was doing a little `flypast` for the owner at an airfield at about 3-400ft.It sounded like a `Gatling` gun firing,and looking at the left wing I could not see it,the right was quite steady.Vibration was also quite severe,and I had to climb,reduce power almost to the stall to stop it.After landing, the aileron bellcrank and pushrod were found to be sheared .Also,although made to specification ,there was insufficient mass-balance on the ailerons.The wings were wooden,and stressed to +-12 g,but I`m sure if they had been metal,it may have been different. The flutter started instantly,and at a speed that I had already tested,but that had obviously weakened the internals. So, what Lyman and M-B are probably seeing on the video is a series of snapshots of the tailplane vibrating,but the frequency may well be above the camera speed.I also agree that there is a slight distortion/alignment there as well. If one looks at the photo on P9,#162,to me it appears that there is slightly more `up` elevator than the left one.I`m only gauging that from the shadows on the mass-balances.Now ,if one is putting UP elevator on one side ,and the tab on the opposite side is forcing Down,then there will be a difference in tension on both sets of elevator cables,and on the bolts holding both torque tubes together.Could lead to cable stretch,possibly sufficient to disengage from the pulleys and guides,or cause the bolts to `fret` or loosen. `Voodoo` appears to have that happen,but there again does not appear to be a comprehensive report about it`s failure either. |
If one looks at the photo on P9,#162,to me it appears that there is slightly more `up` elevator than the left one.I`m only gauging that from the shadows on the mass-balances.Now ,if one is putting UP elevator on one side ,and the tab on the opposite side is forcing Down,then there will be a difference in tension on both sets of elevator cables,and on the bolts holding both torque tubes together.Could lead to cable stretch,possibly sufficient to disengage from the pulleys and guides,or cause the bolts to `fret` or loosen. The plunging, or first flutter mode is when the tips go up and down and the node, the part that doesn't move, is the centerline, as shown in the first part of the video. The counterweights and elevator deflection can drive this; This would be different than the 2nd mode; Hard to tell, but this excited the 3rd mode; God knows what this is, turning a solid to a fluid maybe, and back again' All of these are different than simple control surface flutter that sycamore experienced with the aileron, and up till now, everyone thought the trim tab was doing. Since the HS went into 1st mode flutter, if the video can be believed, then this could also be explained by an elevator getting loose from the torque tube, the fuselage snapping back from ti's twist, and getting things going. Bending the tab spanwise in this mode would explain why the inner part of the tab separated leaving the outer section attached. If the tab rod failed, the whole tab would flutter and rip off in one piece. If the right elevator torque tube attachment failed, and the pilot was pulling 30 pounds of so, the left elevator would be over deflected and the right elevator up load would decrease causing the left roll without a pitch change. It would take a few 1st mode oscillations for the tab to fail, which would happen sooner if it was stiffened after Voodoo, and would happen very fast from the maybe 50 to a 100 hertz. Don't know if he camera can capture 50 hertz, so we might be looking at an illusion. But the theory ties everything in so far; the roll, the fuselage wrinkles, the tab breaking in half, the g occuring after the roll correction... . Found the hinge moment report. The elevator bulge is standard for the D model and there's still a slope change with Mach number on hinge moments. http://naca.central.cranfield.ac.uk/...ca-tn-1302.pdf |
I'll be at RENO next year; maybe I'll get to meet up with Clipped Cub |
Yikes, my old V35 before 94-20-04 R2!!!
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Nice job with the flutter videos Mr. Cub. :ok: You have posted almost all my favorite ones and posted them faster than myself, although Fred Haise's tail flutter video posted earlier on this thread is my all time favorite.
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CC/Anyone, any idea about the tailplane section; was it the earlier,or lower profile.or perhaps an H-model(p51H),which I`m assuming would be somewhat different. Do you know if there are any later reports which would deal with the later models,either Mustang,Bearcat,Jug..?
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Do you know if there are any later reports which would deal with the later models,either Mustang,Bearcat,Jug..? NASA Technical Reports Server The sampling rate of the video is 30 frames per second. Thinking the HS isn't showing flutter, but the left HS deflected down could be a simple overload which would arise if the right elevator let go and the left elevator was over deflected as a result. This would still put all kinds of stress on the tab and the results would be the same. The elevator was the weak point in early dive testing, and with the q's at Reno, the elevator load cycles during the race, the loads increasing on the right elevator due to the tab on the left one, and the higher horsepower, the elevator just gave up in the high g turn. |
The wrinkling of the skin is consistent with the stress on the fuselage, whether the image is part of the failure sequence or not, imo. Downforce and displacement reduces the "area" of the substrate, and the skin, unable to "shrink", wrinkles instead.
I have consistently been impressed with the life cycle of the skin on these birds. It is flexible, and the frame is definitely flexible. This suggests fatigue, and added drag in the circuit. I think there are areas of the airframe that would perform far better wrapped in FRP. It has greater elasticity, and the weight penalty might payoff in better times. Control would be better, the contour and drag would be more consistent, and airflow would be more predictable. In the turns, (all left, of course), the drag of the left Trim Tab on the elevator (with the PITCH UP) would be an ad hoc spoiler, and bleeding some energy with an already "deployed" fence, is an elegant use of otherwise wasted drag. It would be interesting to know if these issues resulted in some additional strengthening in this control. I have the picture that with trim defeated on the right, it is somewhat like driving an automobile with only one front wheel power assisted. |
The wrinkling of the skin is consistent with the stress on the fuselage, whether the image is part of the failure sequence or not, imo. Heard talk of the tailwheel be forced down against hydraulic pressure in the actuator. The maintenance manual shows an uplock and uplocks wouldn't be designed to take torsional loads from the fuselage excessively twisting. There's also what appears to be denting on the turtle deck aboce the, '1', which would indicate the turtle deck in this area was stressed beyond the elasticity of the aluminum from the fuselage overly twisting. http://www.avweb.com/newspics/reno-c...rien_large.jpg |
Notice how the remainder of the trim tab appears indistinct in the photograph that CC has just posted the link to. I wouldn't be surprised if it if fluttering at a high rate and causing that visual effect. Of course anything fluttering at that point in time was not relevant to the final outcome.
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We have found two versions of the telemetry data informally relayed to us. One version indicates that the engine lost power due to fuel interruption from the high g level. Depending on the geometry of the fuel system in the Ghost, it may be possible to estimate peak g required to cause a fuel interruption.
Interruption of fuel can occur due to pump inlet conditions or pump outlet/engine inlet conditions. Was the fuel pump on the Ghost a centrifugal pump or a positive displacement pump? Was it tank mounted or engine mounted? Is the fuel source a wing tank or some other tank? Is there more than one pump involved? |
I also notice in the slo-mo vid that the TT virtually vanishes for an instant before its inboard mount breaks away and then trails the elevator before departing the A/C. Please excuse my ignorance, but are the TTs cable operated, and if so how do they operate with one actuating tab above and one below the elevator surface? Does that mean when one is being pulled on the other is being pushed by the cables (in normal operation)? Also that dent over the number one, is evident in the build photos from 2009, I think its just a characteristic of the modification done to GGs spine.
...2009 Build photos WarbirdAeroPress.com ....2009 Run-up/ck flt WarbirdAeroPress.com I am certainly not questioning the maintainers or the maintenance on this airplane but.......3 of what appear to be 1/4 bolts that attach the inboard elevator hub to its bellcrank? I dont know but seems mighty fragile if one were to consider the torsional stresses placed by pinning one of the TTs stationary. I personally am seeing the logic in the thought that a disconnect between the two elevators may have been the initial failure. Can somebody explain the twitch of GG in the video after passing Rare Bear (approx 7 min into the vid with GG above and in front of RB) (possibly rounding home or #1 pylon)? Just some interesting info: Tech INFO - Aircorps Aviation |
Is there more than one pump involved? but are the TTs cable operated Also that dent over the number one, is evident in the build photos from 2009, I think its just a characteristic of the modification done to GGs spine. Can somebody explain the twitch of GG in the video after passing Rare Bear |
"If you can fly in the mountains, you can fly anywhere".......
Reno/Tahoe is an....interesting environment, for the pilot, year round. Stead is in a "bowl", a well stirred one. I lean toward elevator failure, as well. The right. The left elevator has stress attenuation (at the join/bellcrank) via the tab, the right takes more impact. The difference in load between the two is a chronic source of strain on the mounting cups at the bellcrank. I think the right elevator may have sheared, scrubbed some of the throughbolts that join it to the bellcrank. When it relaxed out of the airstream, the left elevator went stress critical, v/v the Trim Tab. Depending on the severity of the rotational failure of the Right elevator in its mounting, the LHS took on the load we see in Clipped Cub's image. The degree of torsional stress displacement of the tail would have unrigged the Tail feathers out of alignment with the wings and forward fuselage. Permitted an extrapolation, this unrig makes the aft fuselage an emphatic right rudder, with sufficient input to recover the left roll, and roll the a/c back right. The fuselage recoils, and the a/c 'settles' into its ballistic path upward. It also recovers the Pitch Up, as the aft would be drooped, and deflected right. This instant unrig/rerig suggests to me the loud noise heard at the time. The a/c at this speed is a drum, a skinned barrel, no different. |
Wow I had the same though regarding Voodoo.....I wonder if there was much of a roll in his pitch up and accent. Regarding the stock function of the TTs so for ND trimming the left would be pulled and the right would be pushed into the airstream.
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Don't put too much into the parked image of VooDoo, the right elevator is not in alignment with the left, this does not mean what you see is what presented at the moment of failure. It would be interesting to read the record of VooDoo.
I don't see the Trim Tab as failing first, it is stressed by position, not load. It is comfortable in the configuration at failure, whilst the Elevators are not. IOW, the tab is not experiencing any untoward loading. For it to fail, it needs a critical stress point to be exceeded. The failure of the right ELEVATOR explains this critical load nicely. I think Clipped Cub is on to this? |
Thanks CC for your response and explanations.
EDIT: I now see I had the stock operation of the elevator trim tabs reversed, my bad..... Also, upon review of some cockpit photos I believe GGs trim were possibly electric, both pitch and roll.....switches on the left side of the cockpit. |
CC
Has a carb with a float. Float could have been forced down under excessive g creating flooding? Stock P-51 fuel pressure appears to be in the 12-16 psi range with 19 psi max. This is not such a high pressure that it could not be over-ridden at very high g. The Stock P-51 used what appears to be a centrifugal fuel pump on the inboard aft corners of the wing fuel tanks (identified as the booster pump I believe.) http://home.comcast.net/~shademaker/P51Pump.jpg Sample calculations: For 40 inches of height change (this is a SWAG* number), the pressure differential in a column of gasoline is about 1.04 psi. At 15 g, the pressure differential in that same 40 inch column of gasoline is 15.6 psi. These numbers are the same orders of magnitude as the fuel pressure and indicate that interruption of fuel delivery may be possible at high g. The Ghosts fuel arrangement was not stock, and the above calculations may not be relevant to the Ghost. *For the uninitiated, SWAG = Scientific Wild Ass Guess. |
Wrench, if you go to those Tech Notes,and the `flight controls`,you can see the trim layout.Rudder and elevators used the same trim gearboxes.Also in the `tailwheel` section it shows the layout of the elevator/tailwheel /rudder steering mechanism,and locks.
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Just some thoughts.
How do you know the GG was running a float carburettor ? Merlins were fitted with normal carburettors, pressure carburettors and injection carburettors. With all the modifications made to this a/c and its engine, I would not take for granted that anything was standard on this engine. Re the engine cut(if it had a float carb)......if it was due to a rich cut, in all likelyhood you would have seen black smoke from the exhausts due to the over rich mixture....don't see that on any video or still. If it was running a stock fuel system , 12-16psi doesn't seem a lot of pressure to lift fuel to the carb inlet, especially with the reported extremely high G level experienced. So the engine cut could more likely be due to a brief interuption of fuel supply. Again I would be very sceptical that this a/c ran a stock pump/fuel system...maybe it does. With the amount of HP this engine was making , it would require much higher fuel flows and pressures surely ? What makes you so sure the RH elevator or its torque tube failed ? If the RH tab was indeed fixed in the streamlined position , then the LH elevator/tab combination was imparting a force through the LH elevator structure to the RH elevator via the torque tubes and bellcrank. You are forgetting Newtons 3rd law of action and reaction. The forces are equal throughout the system but will be in opposite directions. When it fails, it will be at the weakest point, thats for the NTSB to find out ! Re the tail wheel extension..........it seems it was designed to extend under large G which the pilot was required to pull in the event of tailwheel extension failure. Not supprising it extended here in this case. It has also been mentioned that the doors also came off and this was an indication of structural damage to the tail due to flutter/twist/or the tab failure. The a/c was doing close to 500mph, I don't know of any a/c with a gear limiting speed in excess of 500mph ??? If you extend any gear at that speed, the doors are surely gonna come off !! |
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