jaydeehess
Senior Member
It should also be noted that the copy of the report I link to is authored by one member of the board who balked at blaming crew mismanagement of their aircraft. In his opinion, not enough direct evidence to conclude that.
It should also be noted that the copy of the report I link to is authored by one member of the board who balked at blaming crew mismanagement of their aircraft. In his opinion, not enough direct evidence to conclude that.
The ban will be lifted if he emails me a clear explanation of what he thinks is wrong in the Flutter OP. Specifically why he think's there is not a 20% mandated safety margin above Vd at sea level.
C'mon, Rob: It's time to talk openly about vd...
Perusing PfT forums I found one example of one of his adherents asking essentially the same thing. The reply to that post, " what do you think?"One that the regulations state that the aircraft will be free of flutter through to 20% greater than Vd for constant mach number and altitude.
It seems that SpaceC is objecting that this is to apply for the condition that the aircraft be in level flight and maintaining a constant Mach number, and that the descent of flight 175 and the manouvering of flight 175 negates the effect of the 20% margin contained in the regulations.
I say that "it seems" to be his objection because he has not actually stated it. Instead he has simply repeated the phrase "constant Mach number and constant altitude"
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maybe he forgot what he said.One then wonders why he would not reiterate those points here when asked
Yes, and that airplane lost control and needed the landing gear extended to regain control, and it suffered structural failure (pieces of the aircraft broke off). Did that happen with the aircraft on 9/11? Did they lose control and have to extend their landing gear to regain control? No....
The 727 is also a much faster airplane than the 767. I'd post a Vmo/Mmo comparison, but you still don't even know what each mean.
First of all the aircraft was out of control due to a wildly nonstandard slat configuration, it was not a consequence of the high speed.
Much of the structural failure was due to this nonstandard slat extension and the extending of gear at high speed.
i actually don't think he's lying. He's pretty consistent. I think its a fundamental misunderstanding of the terminology.Yes.
It is the common tactic of 'PfT' to flat-out lie and misrepresent in order to shoehorn their illogical (and incorrect, unsupported) conclusions regarding the airplanes involved on 9/11.
I'm arguing under the premise that radius is the entire area and you are arguing from the premise that radius is half, so the area is TWICE as large.. .
no, I had two directions going at least. ; )It's actually four times as largeBut yes, sometimes what seem like lies can just be a failure to communicate. Especially if clear communication is not a priority.
Which is certainly part of the problem wrt the thread topic and the one respondent. The available evidence indicates that clear communication was specifically and deliberately being eschewed by one poster.It's actually four times as largeBut yes, sometimes what seem like lies can just be a failure to communicate. Especially if clear communication is not a priority.
Ahem, Jaydeehess basically uses some metaphor here and expects us to believe that a rope is comparable to an aircraft. Ok
He also thinks that speed increases the loading which produces a damping effect on the flutter of the aircraft. So this is why it can survive.
He is evidently not aware of the dangers of thicker air at sea level, flying in a dive over VD at sea level is like gradually crashing into a brick wall due to the increasing density of the air.
In fact, VD is established mainly due to varying air resistance at different altitudes.
Does he even know what VD means? It's like he is denying that it means "Vertical Dive Speed"
Beyond VD is the structural failure zone, meaning that if you go over VD at certain altitudes the aircraft will experience flutter and then structural failure, the only margin for this speed only applies in "level flight".
VD for a 767 is 420 KCAS [from sea level] to 17,854 ft/.91M above 23,000 ft
Again, these speeds are established due to the effects of air resistance at different altitudes
He then goes on to say that manuvering while over VD is good for the aircraft because certain parts of it will move out of the destructive conditions.
Jaydeehess, it does not matter whether it is banking at say 45 degrees or not, it is still in a dive and over VD.
In fact, quickly manuvering while over VD is harmful to the aircraft because it is a sharp change in the G-Loads.
This is all irrelevant anyway, because in order to be in a dive the nose has to be pointing down along with the wings, therefore the only way to get out of the VD range (and avoid structural failure) would be to pull up, of course UA 175 did not do that and continued in its dive for over 2 minutes.
The airbus test was done in a dive, in fact the aircraft experienced structural failure even before it reached VD, quite crippling to your claims.
And no Mick, the claim has not been debunked, the safety margin you cited only applies in level flight, so please explain to me how a plane can be diving and be level at the same time.
And how shallow is this dive in flutter testing?
Reduced: 43% of original size [ 1839 x 373 ] - Click to view full image![]()
.To claim that VD speeds are based on constants would negate what VD is
A complete oxymoron
If any of you are reading this right now, which I know you will be doing(because you just cross-posted from this thread) , know that I will not respond to any of you if you intend to respond to this post on Metabunk.
Now it would be obviously hypocritical to claim that I am a coward for not coming to debate you over there, because the fact is you have been invited several times to come here and yet you have declined continuously.
So come over here and state your claims
Having a part come off in flight is NOT structural failure of the aircraft for flight test purposes. I have had reversers and gear doors come off my aircraft at speeds well below Vd and the appropriate limit speeds of those components. We landed safely.
Seriously? So what's V1 and V2 if it's not level? Does it mean all airstrips have to be downhill?I always assumed the "V" in Vd, Vmo, Vc, etc stood for "velocity" now Rob Balsamo informs us that it stands for "vertical". Now that is confusing isnt it?
I always assumed the "V" in Vd, Vmo, Vc, etc stood for "velocity" now Rob Balsamo informs us that it stands for "vertical".
Yes, I noticed my error there and had changed parts of my post to reflect that it was Yost. Missed the first instance of it though.No, I believe that TWCobra was referring to a poster at PfT named "Yost". This is (very likely) the same person who posted here on MB as "Blindidiots", and is not Rob Balsamo.
My opinion is, a Rob Balsamo acolyte who is at the student pilot level. He/she can still be saved with actual facts and knowledge, once out from under the influence of woo being spread by the PfT website.
Uphill would work too.Seriously? So what's V1 and V2 if it's not level? Does it mean all airstrips have to be downhill?
Yost either missed my post #291 ( this thread) or had no comment.
It would be hard to miss by anyone reading and not simply skimming through it.( my first knowledge of it was TWC's post above).It seems "Yost" doesn't want to come back? Wonder if his mistake (i.e., Vd meaning "Vertical dive" was noticed at PfT?
It would be "fair" to allow Mr. Balsamo to correct him.Hardly seems fair for the person to have a mistaken belief in the terminology.
Me. ..., using Fig 5-27 to fake a heavy jet Vg diagram, most anti-intellectual.Clearly you have not ...
This is from page 151 of the Illustrated Guide To Aerodynamics....
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Who is going to correct the Illustrated Guide To Aerodynamics which is used in virtually every Aerodynamics course in every aviation college on this planet? [...]
Balsamo take a training diagram to fake Vg diagram for a 767. And the V-n diagram used is for a light aircraft. Now that sums up the expertise for the silly claims pilots for truth make. The Vg diagram by Balsamo is debunked by Balsamo.
Balsamo photo shopped the V-n diagram to take out the speeds. It fooled Yost and other non-pilots.I would only "hope" that this thread has already been linked to, on the "PfT" site, and that the discussion will attract attention, from there....so that the few left who have not yet seen through the "bunk" of PfT will get a chance...to see it.
ETA...I truly do also hope that some from PfT get a chance to see some more realistic aspects to this discussion. Made by many with (perhaps) more relevant experience on the topic.
Balsamo photo shopped .... take out the speeds. It fooled Yost and other non-pilots.
You hear things like Flt 77 did some fantastic maneuver turn - and when you get the data, you find a sloppy less than standard rate turn with terrible airspeed control.
External Quote:Sec. 25.629 - Aeroelastic stability requirements.
External Quote:
(a) General. The aeroelastic stability evaluations required under this section include flutter, divergence, control reversal and any undue loss of stability and control as a result of structural deformation. The aeroelastic evaluation must include whirl modes associated with any propeller or rotating device that contributes significant dynamic forces. Compliance with this section must be shown by analyses, wind tunnel tests, ground vibration tests, flight tests, or other means found necessary by the Administrator.
(b) Aeroelastic stability envelopes. The airplane must be designed to be free from aeroelastic instability for all configurations and design conditions within the aeroelastic stability envelopes as follows:
(1) For normal conditions without failures, malfunctions, or adverse conditions, all combinations of altitudes and speeds encompassed by the VD/MD versus altitude envelope enlarged at all points by an increase of 15 percent in equivalent airspeed at
External Quote:both constant Mach number and constant altitude. In addition, a proper margin of stability must exist at all speeds up to VD/MD and, there must be no large and rapid reduction in stability as VD/MD is approached. The enlarged envelope may be limited to Mach 1.0 when MD is less than 1.0 at all design altitudes
I have clarified this with my test pilot colleagues; the P4T interpretation is incorrect...
What this means of course is that UA 175 was flying at or below the certified limit for flutter for a 767 until moments before impact. The video that P4T has put out is based on erroneous information and should be treated that way.
Wow. So there is...the serrated condensation trail from the left wingtip/aileron
I doubt there is any evidence of structural failure below Vd solely due to speed
Yes, since Vd marks the cleared part of the envelope, something would have to be very wrong for that to happen. These airliners are very strong. On day one of my initial 747 course I was shown the wing test video where the wings were bent 32 feet upwards before they broke. It made a great impression on me and solidified my confidence in the strength of the airframe.
Below is the B777 test where the wing failed at 154% of the design limit load. Given that the top right of the envelope is VD AT 2.5 G I am guessing that this was equivalent to pulling almost 3.8 G at maximum weight at VD.
It is a nonsense to suggest that Vd marks the structural failure zone at 1G. Balsamo needs to talk with real test pilots like I have and amend his videos accordingly.
W
Undoubtedly the aircraft was on the verge of suffering catastrophic damage due to flutter at this point, the evidence of this can be seen from the serrated condensation trail from the left wingtip/aileron, visible in this video at 0.14. However the evidence shows that destruction from aeroelastic flutter, during the entire approach sans the last few seconds where collision was inevitable, is not possible.