Aircraft Speed Questions |

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Sep 26 2007, 07:34 AM
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#1
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![]() Group: Admin Posts: 9,266 Joined: 13-August 06 Member No.: 1 |
I have been getting alot of emails with questions on max speed for 9/11 aircraft. So i decided i will post the reply here and anyone can use the link as they see fit.
QUOTE According to AA77 FDR, speed recorded was 463 knots at end of recording. Velocity-Max-Operating (Vmo) for a 757-200 is 350 knots. A 757 can exceed 350 but we are trying to find out through connections at Boeing by just how much before the plane starts to experience structural damage (and other factors due to high speed at low altitude). 463 knots seems excessive.
We do not currently have the numbers for the 767 as we have not analyzed the events in NYC yet. We are still currently working on UA93 and AA77. However, i dont think the speeds differ too much from the 757. Hope this helps. |
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Sep 26 2007, 07:44 AM
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#2
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Group: Valued Member Posts: 1,743 Joined: 19-October 06 From: European Protectorate Member No.: 110 |
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Sep 26 2007, 07:49 AM
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#3
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![]() Group: Admin Posts: 9,266 Joined: 13-August 06 Member No.: 1 |
Peter (or any other pilot reading this),
See if you can dig out Vmo for the 76 from a 76 limitations manual (or if you know someone). I need the envelope number.. .not the bird strike number. .sea level to 10,000 (or whatever). I also just sent an email to some of the other guys to help dig out the number (although they do not check their email often, so it may take awhile). Im tired of getting distracted by these questions. The "767 cannot exceed 240 mph at 700 AGL" is hogwash. 240 mph is 208 knots. The 767 probably exceeds that on climbout... Although i agree the reported speeds seem excessive for all the 9/11 aircraft, we need some solid numbers for the 76. We have them for the 75. |
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Sep 26 2007, 08:03 AM
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#4
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Group: Valued Member Posts: 1,743 Joined: 19-October 06 From: European Protectorate Member No.: 110 |
I've asked too low, terrain (767 pilot) to post the manual data here.
He is between 2 flights and will try to reply a.s.a.p. |
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Sep 26 2007, 08:04 AM
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#5
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![]() Group: Admin Posts: 9,266 Joined: 13-August 06 Member No.: 1 |
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Sep 26 2007, 09:13 AM
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#6
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Group: Newbie Posts: 4 Joined: 11-November 06 Member No.: 222 |
Speed limits B767:
turbulent airspeed: 290kt/.78M Vmo/Mmo: 360kt/.86M gear extend: 270kt/.82M gear retract: 270kt alternate gear extension: 250kt/.75M max tyre speed: 225mph (= 196 kt) min speed above FL250: Vref30+100 kt min speed for clean LDG: Vref30+50 kt Greetings TLT |
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Sep 26 2007, 09:55 AM
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#7
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![]() Group: Admin Posts: 9,266 Joined: 13-August 06 Member No.: 1 |
Good to see you TLT....
thanks for posting the numbers.... (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/cheers.gif) (pinned for now) |
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Sep 26 2007, 11:57 AM
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#8
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Group: Valued Member Posts: 1,743 Joined: 19-October 06 From: European Protectorate Member No.: 110 |
Danke TLT!
(IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/cheers.gif) That was quick! Have a nice flight to ZBAA. Peter |
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Sep 26 2007, 01:28 PM
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#9
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∞* M E R C U R I A L *∞ Group: Valued Member Posts: 5,870 Joined: 25-August 06 From: SFO Member No.: 16 |
Thanks, Rob. This seems to be a 'burning question' at the moment.
Pilots, please keep in mind that the rest of us do not speak 'aviation'. If anyone has the time to give us a translation that the rest of us can comprehend, it would be greatly appreciated! |
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Sep 27 2007, 11:59 AM
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#10
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Group: Valued Member Posts: 1,743 Joined: 19-October 06 From: European Protectorate Member No.: 110 |
QUOTE (too low @ terrain,Sep 26 2007, 03:13 PM) Speed limits B767: turbulent airspeed: 290kt/.78M Vmo/Mmo: 360kt/.86M gear extend: 270kt/.82M gear retract: 270kt alternate gear extension: 250kt/.75M max tyre speed: 225mph (= 196 kt) min speed above FL250: Vref30+100 kt min speed for clean LDG: Vref30+50 kt Greetings TLT Painter, took me a little time to answer - I am working rather a lot these days. VMO/MMO = maximum operating limit speed is a speed that may not be deliberately exceeded in any regime of flight (climb, cruise, or descent) Question: Why are there two speeds, i.e VMO-slash-MMO Answer: VMO/MMO refers to "Airspeed or Mach Number, whichever is critical at a particular altitude (Remark: Mach no. is usually not calculated below 25,000 ft) VMO is based on the IAS (indicated airspeed), which is simply speaking measuring the plane's aerodynamic drag. This aerodynamic drag gets lower in thinner air = on higher altitudes. A constant indicated airspeed results in a higher Mach number and a higher True Air Speed=TAS, the higher a plane flies. Examples: _Alt MSL_IAS__TAS__mph__Mach ___500ft 290kt 290kt 334 0.44 _1,000ft 290kt 296kt 340 0.45 10,000ft 290kt 348kt 400 0.54 25,000ft 290kt 435kt 501 0.72 35,000ft 290kt 493kt 567 0.86 = speed limit So if a 767 is flying 645 mph at 700 ft MSL see NTSB Report On Ua 175 - thread it is exceeding it's maximum operation limit speed of 360 kt by 55% _Alt MSL_IAS__TAS__mph__Mach __ 700ft 360kt 360kt 414 0.54 __700ft 560kt 560kt 645 0.85 Make your own calculations: Mach Number calculator http://www.grc.nasa.gov/WWW/K-12/airplane/mach.html True Airspeed calculator http://www.csgnetwork.com/tasinfocalc.html The other speeds indicated by TLT are self explanatory. Vref has nothing to do with the govt loyalist site, but rather with a calculated take-off speed depending on take-off weight and flaps setting (hope I am correct here). Final thing: ZBAA is Beijing, just in case you were wondering. (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/wink.gif) *EDIT* forgot to mention: the fact, that the max. gear retract (extend) speed and the max. speed in turbulent air are considerably lower than Vmo is a clear indication, how 'vulnerable' the airframe can be in case of a speed exceed. . |
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Sep 29 2007, 10:23 AM
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#11
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Group: Active Forum Pilot Posts: 903 Joined: 18-October 06 Member No.: 107 |
QUOTE So if a 767 is flying 645 mph at 700 ft MSL see NTSB Report On Ua 175 - thread it is exceeding it's maximum operation limit speed of 360 kt by 55% I've had a few but don't these two speeds need to be of the same pedigree to arrive at that percentage? Or have I had enough? (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/cheers.gif) |
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Sep 29 2007, 02:08 PM
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#12
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Group: Valued Member Posts: 1,743 Joined: 19-October 06 From: European Protectorate Member No.: 110 |
Problems with my English or with my maths, Timothy?
Anybody else confused? 645 mph = 560 kts = 1.55 times 360 kts or 360kts +55% = 560kts = 645 mph (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/cheers.gif) Zap |
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Sep 29 2007, 06:07 PM
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#13
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Group: Active Forum Pilot Posts: 903 Joined: 18-October 06 Member No.: 107 |
QUOTE Problems with my English or with my maths, Timothy? No, the problem is not yours. It was my lack of comprehension. (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/doh1.gif) |
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Sep 29 2007, 11:17 PM
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#14
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Group: Valued Member Posts: 1,743 Joined: 19-October 06 From: European Protectorate Member No.: 110 |
_Alt MSL_IAS__TAS__mph__Mach
__ 700ft 360kt 360kt 414 0.54 __700ft 560kt 560kt 645 0.85 Looking back the problem might have been my confusing tables in plain text. I'll have to find a better way to post them. |
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Sep 30 2007, 03:44 PM
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#15
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Group: Newbie Posts: 4 Joined: 11-November 06 Member No.: 222 |
QUOTE (Zapzarap @ Sep 27 2007, 10:59 AM) The other speeds indicated by TLT are self explanatory. Vref has nothing to do with the govt loyalist site, but rather with a calculated take-off speed depending on take-off weight and flaps setting (hope I am correct here). The ref speed changes constantly during the flight. When you lose weight (burn fuel) the ref speed becomes lower. E.g.. You take off with mtow (186880kg) the Vref30 speed is 176 kt and after e.g. 10 h flight you land with 132000 kg the Vref30 is 139kt that means: minimum clean speed ist Vref30+80kt = 219kt. Thats the lowest speed you can fly wihout using flaps. If your reduce speed below 219kt you have to select flap1, now lowest speed you can fly ist Vref30+60 = 199kt, ... than flap5 lowest speed Vref30+40=179, ... than flap20 lowest speed is Vref30+20=159 (normally you order at this flapsetting gear down) ... than flap30 and lowest speed is Vref30 and you fly the approach at least with vref30+5 in your example 144kt (if there is no headwind component > 5). I prefer the Boeings! (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/wink.gif) |
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Sep 30 2007, 04:18 PM
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#16
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Group: Valued Member Posts: 1,743 Joined: 19-October 06 From: European Protectorate Member No.: 110 |
Thanks for the clarification, TLT
What is your take on the 767 flying far beyond VMO? How fast can a 767 fly at full throttle? (close to the ground?) (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/wink.gif) Zap |
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Dec 12 2007, 06:51 PM
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#17
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Group: Newbie Posts: 2 Joined: 9-November 07 Member No.: 2,463 |
My question would be...
How could the people responsible for 911 make such a simple mistake as allowing NIST and other organizations come out with speeds exceeding the aircraft's ability? And since some believe there were no planes (ignoring the fact hundreds of people gathered in crowds to watch the fire burn in tower 1, then witnessed the second plane hit, and the fact not one person has come out to protest the media's coverage and say they were there and saw no plane but saw it on TV later that day) why would they show the cgi aircraft exceeding the aircrafts limits? That makes no sense. (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/nonono.gif) I understand normal pilots don't push the aircraft for safety reasons, but can it be the aircraft was pushed since whom ever was piloting the aircraft (human or computer) didn't care since it was going to be destroyed anyway? (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/pilotfly.gif) |
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Dec 16 2007, 11:48 AM
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#18
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Group: Valued Member Posts: 2,170 Joined: 29-September 07 From: Hampshire, UK. Member No.: 2,274 |
QUOTE (TruthgoneWild @ Dec 12 2007, 05:51 PM) I understand normal pilots don't push the aircraft for safety reasons, but can it be the aircraft was pushed since whom ever was piloting the aircraft (human or computer) didn't care since it was going to be destroyed anyway? (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/pilotfly.gif) Those who would have been controlling the aircraft, if indeed the air vehicles were as described in the Authorized Version, would have been very concerned not to exceed structural limits for to do so could bring on failure and unpredictable behaviour, missed targets and the negating of any careful preparation of those targets for a plausible (I realize most here consider the official version implausible if not impossible) rationale behind the eventual destruction of those targets by the pre-planned explosive demolition. |
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Apr 12 2008, 08:58 AM
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#19
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Group: Student Forum Pilot Posts: 8 Joined: 14-January 07 From: bizzaro world Member No.: 446 |
Hi all,
My experience having flown Boeings for the last 13 years, 8 on the767 is that Mr.Boeing builds them very strong.... I recall an incident quite some years ago where a Chinese registered B747SP got itself into a spin and fell from 35+ thousand feet to below 10 thousand. It more than doubled its structural G limits not to mention substantial rolling G (turning whilst pullling G, a definate No No!) Lost a few panels and gear doors, hydraulic systems etc. and popped a few hundred rivets but kept flying. (By the way they didn't want to report this, but that's another story altogether.) (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/spin.gif) Where the problem comes I believe (having tried it in the simulator) is ground effect at these high speeds...you just cannot get the a/c to fly with any stability at a few feet off the ground. Maybe someone with more mathematical ability than me and a good understanding of the physics of ground effect could come up with some numbers to show the significance of ground effect at 460Kts+ Cheers (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/cheers.gif) |
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Apr 13 2008, 05:42 PM
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#20
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Group: Valued Member Posts: 3,772 Joined: 14-December 06 From: Fort Pierce, FL Member No.: 331 |
Transport aircraft are not meant to fly close to the ground, except configured during landing. Flying at that speed that close to the ground would be virtually impossible, or require special equipment such as that Nap of Earth flying, or whatever it's properly called.
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