> Sigh... Please show me a small aircraft which has a Vmo. Wow... just wow.
Which has nothing whatsoever to do with anything I've said about Vd. I'm afraid you'll need to pick up your game to even rate a "nice try."
> > I'm not the one confusing load with speed.
> Yes you are. You said...
> "The way the engineers assured the planes could fly at their Vd velocities WITHOUT falling apart is by adding a 50% margin of safety." - http://www.democraticunderground.com/?com=view_post&forum=1135&pid=7451
> You are wrong. But nice try at backpedaling.
LOL, what a pantload. In the sentence before that, I defined Vd as "the shallow-dive velocity the engineers assumed when they calculated the forces the plane's structure needed to withstand." Those calculated forces would be the design loads, and anyone familiar with any type of structural engineering would know that calculated design loads are always multiplied by a Factor of Safety. You clearly did not know that -- apparently still don't know that -- so you misinterpreted what I meant. Now, I can see how someone unfamiliar with standard engineering practice -- such as yourself, as we now know -- could misread what I wrote, but when I saw that you were incorrectly interpreting it as 50% greater speed, I made it quite clear what I meant in the post you responded to: "the way that the engineers will insure that Vd 'is by definition a safe speed' is to multiply the calculated loads by a Factor of Safety, which is typically 1.5." We have both proved that statement correct, your misreading of my first post notwithstanding, so this lame attempt at misdirection also falls short of a "nice try."
> >Your expert appears to be confused
> Says the guy who just a few short days ago didn't even know what Vd was and thought there was a 50% margin of safety attached to Vd.... lol. Now apparently he thinks he knows more than AOPA. Too funny..
Well, now, this is another "interesting" argument, Rob. Your expert says, "This speed is known as Vd or design dive speed" when he is clearly talking about what the rest of the world seems to call the "demonstrated flight diving speed" Vdf. Now, you seem to be suggesting that since I only learned about either of those terms recently, I must be the one confused about their meaning and the difference between them? Because, AOPA? Are you sure that's the argument you want to make, or would you like to take another stab at it?
But the really funny part is trying to sneak in your own ignorance of the 50% Factor of Safety under the same fallacious argument, as if the AOPA writer was equally ignorant and would agree with you. I seriously doubt it, but who cares; the fact remains that FoS load multipliers are standard engineering practice and hand-waving from self-proclaimed experts doesn't make them disappear.
> >Are you aware that people can look this stuff up on Google?
Yes. You should try it.... and don't stop when you think you have an answer which suits your bias. Because as you have seen, you tend to be wrong... alot.
Oh, I "try it" all the time, which is how I found that you were confused about things like Mcrit and Vd. Yeah, you claim I'm wrong -- a lot -- but you always come up short when it's time to substantiate, and here we go again. You'd much rather play debating games, which you aren't particularly good at, either.
> The margin of safety for speed is between Vmo and Vd on transport category aircraft.
Yes, Vmo is limited by Vd, and yes that is a margin of safety. What's in dispute is your ridiculous contention that that's the ONLY margin of safety -- a contention which clearly denies the 50% safety factor built into the design loads. The Boeing slide presentation I linked to gives their definition of margin of safety: It's just the difference between actual loading and maximum loading, all relevant factors considered -- no mention of Vmo or Vd.
> This is not just "At Boeing". This is an FAR Requirement and applies to both Boeing and Airbus. You'd know this had you actually used google and didn't stop when you found something to support your bias.
Sorry, lost my composure for a minute there... So you are now saying that engineers are REQUIRED by the FAA to design planes to be flutter-free at 1.15 Vd -- something you seem to have curiously omitted from your videos and diagrams -- and if I hadn't stopped when I found something to "support (my) bias," I would have found lots more to support my "bias"? Should I take that as the net result of your attempt to find something to support your claims? What a hoot.
But seriously (if I can stop laughing), and no offense, but how about providing a link so we can see what the FAR requirement really says. I just have a feeling you're leaving out some interesting stuff.
> There is a theoretical margin of 1.15 for Vd under Part 25 (1.2 under Part 23), but this is theoretical and for a constant altitude and mach... ie not maneuvering...
Oh, I see; it's "theoretical" so it's okay to completely ignore that it refutes your argument?
> This does not apply to aircraft which are maneuvering (such as were the aircraft on 9/11).... and precedent has proven as such.
By "maneuvering" do you mean the banks the WTC planes did immediately before hitting the buildings, and the 2G pull-up that AA77 did at the Pentagon? That's the only "maneuvering" I'm aware of at the impact speeds. It's certainly possible that that "maneuvering" did indeed cause structural damage, but it seems the pilots weren't too concerned about that for some reason. That's another gaping hole in your logic, actually: Perhaps the planes did suffer structural damage, but so what? Seconds later, it was all just mass times velocity.
> Many aircraft (including Boeing and Airbus) have suffered structural failure well below 1.15Vd.
Here's how that works: "Many have" does not prove your point, but "some have not" would disprove it. And some have not, such as Federal Express 705, which disproves your contention, so you just deny all examples or try to find excuses for treating them differently.
> The Flight Maneuvering Envelope is posted above under FAR Part 25. It is not fake.
That's nice that it's only your interpretation of them that's fake, but my question was, have you stopped using your fake "767 Fg diagram" to promote your video? That (and many other examples) gets to the question of why your credibility is zero among those who have observed your antics over the years. I haven't forgotten when you posted a graphic on the old September 11 board with a compass rotated away from north to "prove" your contention about AA77's flight path. When exposed, you neither apologized nor admitted that the correct compass orientation disproved your contention. You just went into "Balsamo mode" -- shotgun blasts of diversions, strawmen arguments, non sequiturs, insults, and third-grade bullying.
> Again.. The "50% margin of safety" in which you claimed applied to Vd, is for G loads, not speed.
And again, what I actually said is right there for anyone to read, and again the far bigger issue is that someone who claims to be an expert on plane failure is apparently oblivious to how planes are designed.
> The wing broke at 154%, it passed limit load certification. And as you can see, it had nothing to do with speed. Unless of course you think the building in which the testing was performed, was traveling at Vd.
It's really amusing to watch you refute yourself and then try to pretend that it means you were actually right all along, somehow. I don't believe that I've ever seen anyone who thought that was a effective debate tactic, but you seem to use it a lot.
So here's the story so far: Hey, kids, someone who wants to sell videos which claim that the 9/11 plane speeds were "impossible" because they exceeded their Vds was apparently unaware that Boeing jets are designed to get to 1.15 Vd without flutter, and that a 50% Factor of Safety (or more) is typically added to ALL design loads, not just G loads. This self-proclaimed expert who appeals to own authority averages more than one misstatement, logical fallacy, or obfuscation per paragraph, but don't let that stop you from buying his videos.
On the other hand, the board was getting pretty boring so thanks for the entertainment, Rob.
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