gumboot
lorcutus.tolere
- Joined
- Jun 18, 2006
- Messages
- 25,327
No. For any wing, there is an angle of attack for which the lift of the wing is zero. Since you can go all the way to zero, then given airspeed above the stall, there's some point where you can reach the lift that just balances your weight.
Sorry, let me correct. A boeing 707 can't fly level at low altitude at 600 MPH.
We're talking about the liklihood of a 707 hitting the WTC at 600 MPH. Putting aside dive bombing attacks, I can't see this ever happening.
According to this chart:
Boeing 707-320C Never exceed speed (VNE) is 425 KCAS (Knots calibrated air speed).
At cruise altitude (25,000ft) 425 KCAS is Mach 0.99 or 597 KTAS (True Air Speed) (the chart actually says Mach 0.95 as Maximum Mach, allowing for a buffer, I suppose, or possibly allowing for variations between Indicated Air Speed and Calibrated Air Speed).
In contrast, if the 707 hit the WTC, at that altitude the VNE of 425 KCAS is Mach 0.66 or 425 KTAS. (Assuming no wind, with nominal atmospheric conditions, Indicated, Calibrated, and True airspeeds are all the same (and the same as ground speed) at sea level).
Hence 600 MPH (520 Knots) at sea level exceeds a Boeing 707's Never Exceed Speed (VNE) by 15%.
Theoretically airframe integrity begins to be compromised at VNE. Would a 707's wings tear off at 15% over VNE? I don't know. But I can't imagine a scenario in which a 707 would ever hit the WTC at that speed.
Of course, it is almost certain that the people doing the calculations simply looked up typical cruise speed and calculated the WTC's survivability based on that. I'm not saying they didn't determine it for that speed.
I'm just saying a scenario with an impact at that speed was never going to happen.
(Incidentally, on the same charts no VNE for the Boeing 757 or Boeing 767 is given...)
-Andrew