Aircraft Control and Barber Pole
Do a Hover - it avoids G
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Ralph
At face value your first post could indicate that you are serious.
However
You are anonymous.
You give no details of your industry background.
The relationship between Vmo and Vd is a matter of regulation and flight test.
You ask people to give their views based on their experience when by definition they have no experience of what you are asking about.
You give no indication of what you intend to do should anybody respond along the lines you request.
So please don't hold your breath.
JF
At face value your first post could indicate that you are serious.
However
You are anonymous.
You give no details of your industry background.
The relationship between Vmo and Vd is a matter of regulation and flight test.
You ask people to give their views based on their experience when by definition they have no experience of what you are asking about.
You give no indication of what you intend to do should anybody respond along the lines you request.
So please don't hold your breath.
JF
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DC-8 / test, response
There are several mishap/recovery examples recording response during HIGH SPEED dive, available in Accident Rpts, eg:
-- N840TW / 4Apr79,
-- B747SP / N4522V / 19Feb85,
-- A310-308 / 22Mar94 / F-OGQS, “Glinka”.
From flight test reports you can gather various responses during high-speed testing, here's one:
DC8-43 / 21Aug61, RR Conway M512 engines, N9604Z, in Canadian Pacific livery, with Flight Test Instrumentation:
-- climbed to PA = 50,029' at GW =170,600 Lbs; Set-up stab trim for dive (to aid in recovery) so that elevator push force = 50 Lbs (with CG = 27% MAC); set T/O Thrust, pushed nose down to -22 degrees pitch attitude.
-- In dive over Edwards AFB: Max TAS @ 39,614' of 662.5 MPH achieved true Mach = 1.012 at 41,088' (Indicated Mach was .96).
-- Recovery: at 42000' full up elevator yielded no change in G's! and Stabilizer Trim would NOT function. Had to relax elevator, reset trim from 0.5 to 1.5 a.n.u. which resulted in 1.7 G's by 36,000'. Descending through 42000' noted Aileron Buzz of 36 cps, and rudder buzz of 28 cps (disappeared by 36000'); buffet at 35,000' while slowing through M=.94.
[per AAHS Journal Spr '92, by WF Smith]
-- N840TW / 4Apr79,
-- B747SP / N4522V / 19Feb85,
-- A310-308 / 22Mar94 / F-OGQS, “Glinka”.
From flight test reports you can gather various responses during high-speed testing, here's one:
DC8-43 / 21Aug61, RR Conway M512 engines, N9604Z, in Canadian Pacific livery, with Flight Test Instrumentation:
-- climbed to PA = 50,029' at GW =170,600 Lbs; Set-up stab trim for dive (to aid in recovery) so that elevator push force = 50 Lbs (with CG = 27% MAC); set T/O Thrust, pushed nose down to -22 degrees pitch attitude.
-- In dive over Edwards AFB: Max TAS @ 39,614' of 662.5 MPH achieved true Mach = 1.012 at 41,088' (Indicated Mach was .96).
-- Recovery: at 42000' full up elevator yielded no change in G's! and Stabilizer Trim would NOT function. Had to relax elevator, reset trim from 0.5 to 1.5 a.n.u. which resulted in 1.7 G's by 36,000'. Descending through 42000' noted Aileron Buzz of 36 cps, and rudder buzz of 28 cps (disappeared by 36000'); buffet at 35,000' while slowing through M=.94.
[per AAHS Journal Spr '92, by WF Smith]
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Quote:
Stabilizer Trim would NOT function.
Gosh, I wonder why?
Common, with early design jet transport aircraft, in such extreme situations.
And yes, I know of the pilots that did so, with the DC-8.
707, similar, except...M.96 not exceeded.
IE: with the 707, severe mach tuck would be experienced at mach numbers exceeding M.85.
NOT a pleasant experience...
Mach tuck with the L1011...hardly noticable, due to the superior design.
Burbank got it right with their superb wing design.
L1011, in a class of its own, in aeronautical terms.
IE: the gold standard, to which others hope to attain.
From all reports previously, deHavilland got it right with the DH, (later HS.) 121 Trident.
Trident...a good hi-speed design, from the get-go.
Triplex autoland was superb, as well.
Stabilizer Trim would NOT function.
Gosh, I wonder why?
Common, with early design jet transport aircraft, in such extreme situations.
And yes, I know of the pilots that did so, with the DC-8.
707, similar, except...M.96 not exceeded.
IE: with the 707, severe mach tuck would be experienced at mach numbers exceeding M.85.
NOT a pleasant experience...
Mach tuck with the L1011...hardly noticable, due to the superior design.
Burbank got it right with their superb wing design.
L1011, in a class of its own, in aeronautical terms.
IE: the gold standard, to which others hope to attain.
From all reports previously, deHavilland got it right with the DH, (later HS.) 121 Trident.
Trident...a good hi-speed design, from the get-go.
Triplex autoland was superb, as well.
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Vmo exceeded by 100 kt on a 737-700 during a flight test that went horribly wrong:
http://www.pprune.org/rumours-news/3...2-january.html
Cheers
P
http://www.pprune.org/rumours-news/3...2-january.html
Cheers
P
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Thank you all for your very thoughtful replies.
Just one more question.
Is there anyone here that feels an aircraft will be stable/controllable at 150 knots over the barber pole of that aircraft, at any altitude, and if so, can you please find one that has been positively identified to achieve such excessive speeds over it's barber pole?
(ok, so I guess that was two questions)
Thanks in advance for any input.
Just one more question.
Is there anyone here that feels an aircraft will be stable/controllable at 150 knots over the barber pole of that aircraft, at any altitude, and if so, can you please find one that has been positively identified to achieve such excessive speeds over it's barber pole?
(ok, so I guess that was two questions)
Thanks in advance for any input.
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Originally posted by John Farley
He's not. RalphTheMouth is a 9/11 Truther.
Ralph is most likely XXXXX of Pilots for 9/11 Truth.
King Air pilot and professional 9/11 Truther.
You see, John, Ralph here believes that Flight 175 (the second plane to hit the towers) would not have been able to achieve it's reported 500 knot impact speed without significant modifications to the airframe and engines. He also believes that there were no hijackers at the controls because it would've been impossible for inexperienced pilots to control the aircraft at 150+ knots over Vmo.
That's right, Ralph believes that Flight 175 was flown into the tower via remote control.
Let's all hope that Ralph holds his breath so that there will be a lot less conspiracy nonsense on this board.
Ralph
At face value your first post could indicate that you are serious.
At face value your first post could indicate that you are serious.
You are anonymous.
You give no details of your industry background.
So please don't hold your breath.
That's right, Ralph believes that Flight 175 was flown into the tower via remote control.
Let's all hope that Ralph holds his breath so that there will be a lot less conspiracy nonsense on this board.
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At face value your first post could indicate that you are serious.
However
You are anonymous.
You give no details of your industry background.
The relationship between Vmo and Vd is a matter of regulation and flight test.
You ask people to give their views based on their experience when by definition they have no experience of what you are asking about.
You give no indication of what you intend to do should anybody respond along the lines you request.
So please don't hold your breath.
JF
However
You are anonymous.
You give no details of your industry background.
The relationship between Vmo and Vd is a matter of regulation and flight test.
You ask people to give their views based on their experience when by definition they have no experience of what you are asking about.
You give no indication of what you intend to do should anybody respond along the lines you request.
So please don't hold your breath.
JF
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It appears "Ralph" is seeking confirmation from outside his/her own collection of "expert" pilots, which is indeed an infinitesimally small sampling of aviation professionals.
Hi, GR53. It appears that you are familiar with "Ralph's'' claims of "impossible speeds" and that his "expert" pilots could not hit the World Trade Center in a 767 if they had to. I believe some of them even tried to do it in a simulator and claim that they failed. LOL!
Remind me not to fly with that group of incompetents.
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A google search came up with this: 9/11 even real pilots couldn't do it, page 1
Ralph here believes that Flight 175 (the second plane to hit the towers) would not have been able to achieve it's reported 500 knot impact speed without significant modifications to the airframe and engines.
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... so an un-named power develops a nefarious plot to fly an airliner into a building, and instead of simply using a normal airframe and 300 odd knots, decides to re-develop the airframe simply in order to achieve a slightly (in terms of damage done) impact speed of 500 knots?
Don't forget, this group of pilots also believe that the aircraft was remote piloted into the tower.
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Ralph has a good question.
Would the manufacturers be interested in answering it ... ?
On the Airbus side they really don't want their airplanes to go over VMO. High speed protection would trigger and take control from the pilot at VMO + only 4 knots ... they must have a reason for that ... ?
Would the manufacturers be interested in answering it ... ?
On the Airbus side they really don't want their airplanes to go over VMO. High speed protection would trigger and take control from the pilot at VMO + only 4 knots ... they must have a reason for that ... ?
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No OEM wants their aircraft above Vmo. Whether the protection is automatic flight envelope limiting (as described), semi-automatic (most AP systems or At systems wont let you go past Vmo plus "a bit") or manual (various warnings going off when Vmo is exceeded) its always the same - don't go past Vmo.
Why? Because that is the legally certified maximum speed for normal operation. it's the maximum speed where the aircraft has been shown to comply with every single regulation required to be given a type certificate.
What it is emphatically NOT is a deadly cliff edge, past which certain death awaits. in fact, in order to be allowed to publish that Vmo speed, the OEM has done a huge amount of work demonstrating that considerable margins exist at that speed, and has tested the aircraft well in excess of that speed.
To deduce from a speed limit that it must be incredibly dangerous or impossible to go above that speed would be akin to looking at the speed limit on a British motorway, say, at 70mph, and saying "well, obviously they put that limit there because it's certain death to drive at 75mph". Nonsense. It IS more dangerous at 75 than at 70 (and indeed also more dangerous at 70 than at 65 or 60), and the 70 number is to some extent chosen based on an acceptable level of danger, and then used for various design considerations (like the radius of curves in the road, or the strength of the crash barriers, and so on). But until something else goes wrong, people can happily race past at 100mph, with the biggest danger being to their wallets and their driving priviledges.
Why? Because that is the legally certified maximum speed for normal operation. it's the maximum speed where the aircraft has been shown to comply with every single regulation required to be given a type certificate.
What it is emphatically NOT is a deadly cliff edge, past which certain death awaits. in fact, in order to be allowed to publish that Vmo speed, the OEM has done a huge amount of work demonstrating that considerable margins exist at that speed, and has tested the aircraft well in excess of that speed.
To deduce from a speed limit that it must be incredibly dangerous or impossible to go above that speed would be akin to looking at the speed limit on a British motorway, say, at 70mph, and saying "well, obviously they put that limit there because it's certain death to drive at 75mph". Nonsense. It IS more dangerous at 75 than at 70 (and indeed also more dangerous at 70 than at 65 or 60), and the 70 number is to some extent chosen based on an acceptable level of danger, and then used for various design considerations (like the radius of curves in the road, or the strength of the crash barriers, and so on). But until something else goes wrong, people can happily race past at 100mph, with the biggest danger being to their wallets and their driving priviledges.
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This subject has been discussed before on this forum. See:
http://www.pprune.org/tech-log/28296...mic-limit.html
Vmo/Mmo limits can exist for a variety of reasons. Flutter, Certification limits, Mach Tuck effects, etc. Down low, you can go pretty darn fast without bumping Mach limits. As long as you don't run into a flutter limit or a bird while accelerating, there ought to be enough thrust to get up to at least 500 knots. As long as your controls are still working conventionally, flying into a building shouldn't be hard to do. I've been much faster down low and about the only difference is a much larger turn radius and the greater beating you get from turbulence down low.
If you will remember, both aircraft hit with significant bank angles. This could be the result of an intent to increase multi-floor damage on the part of the bad guys, or simply the result of alignment turns as they got in close.
http://www.pprune.org/tech-log/28296...mic-limit.html
Vmo/Mmo limits can exist for a variety of reasons. Flutter, Certification limits, Mach Tuck effects, etc. Down low, you can go pretty darn fast without bumping Mach limits. As long as you don't run into a flutter limit or a bird while accelerating, there ought to be enough thrust to get up to at least 500 knots. As long as your controls are still working conventionally, flying into a building shouldn't be hard to do. I've been much faster down low and about the only difference is a much larger turn radius and the greater beating you get from turbulence down low.
If you will remember, both aircraft hit with significant bank angles. This could be the result of an intent to increase multi-floor damage on the part of the bad guys, or simply the result of alignment turns as they got in close.
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Don't forget, this group of pilots also believe that the aircraft was remote piloted into the tower.
So, they claim these were "beefed-up" aircraft, structurally and engine-wise with remote-controlled capabilities added to the airframe.
Which takes us back to the opening post's question - "Aircraft Control and Barber Pole." If "Ralph", who is most assuredly XXXXXXX, ever comes back, I would like him to answer the question if conventional pilots could not control an aircraft at those speeds, what makes him think a remote-controlled one would, with a modified or-not 767?
Methinks XXXXX won't be back to answer.
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Is it customary to ALLEGE the identity of posters on PPRUNE?
If so, it appears ADDIS77 (and his sock GR53), both registered Sept 2010, is XXXXXXX, a wannabe "Tom Cruise" obsessed with XXXXXXX. You see, XXXXXXX was so upset he couldn't make it to Top Gun (let alone the front seat), he decided to take it out on others who actually have, such as XXXXXX and XXXXXXXx.
[List of CVs of various folk probably isn't necessary - JT]
People like ADDIS77/XXXXXX feel it is "easy" to control a 767 at Vmo+150, Va+220 --and pull G's-- out of a 10,000+ foot dive, while rolling on G's cranking into a 38 degree bank, to hit a target with less than a 25' margin for error - for a pilot with less experience than one who couldn't control a 172 at 65 knots.
Does anyone here agree with him that such a maneuver is "easy"?
If so, it appears ADDIS77 (and his sock GR53), both registered Sept 2010, is XXXXXXX, a wannabe "Tom Cruise" obsessed with XXXXXXX. You see, XXXXXXX was so upset he couldn't make it to Top Gun (let alone the front seat), he decided to take it out on others who actually have, such as XXXXXX and XXXXXXXx.
[List of CVs of various folk probably isn't necessary - JT]
People like ADDIS77/XXXXXX feel it is "easy" to control a 767 at Vmo+150, Va+220 --and pull G's-- out of a 10,000+ foot dive, while rolling on G's cranking into a 38 degree bank, to hit a target with less than a 25' margin for error - for a pilot with less experience than one who couldn't control a 172 at 65 knots.
Does anyone here agree with him that such a maneuver is "easy"?
Last edited by RalphTheMouth; 20th Oct 2010 at 01:19.
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Ralph has a good question.
Would the manufacturers be interested in answering it ... ?
Would the manufacturers be interested in answering it ... ?
Question: "So there is no way that a 767 could be going 500 mph at 700 ft altitude?"
Boeing spokeswoman XXXXX replies with laugh, "Not a chance".
Scroll forward to 2:57 as the first call is inaccurate
You can see more interviews with United and American Airlines 757/767 Captains, both who have actual command time in the aircraft reportedly used on 9/11, here.
Full Film - 9/11: World Trade Center Attack - Pilots For 9/11 Truth Forum
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I can see that many estimates on the speed of UA175 have been produced.
Knowing the skyline of NY and the spots from where the few available video were taken, isn't it possible, probably by using goggle earth and some basic trigonometry, to produce one more estimate that could confirm or not what has been published already ?
Knowing the skyline of NY and the spots from where the few available video were taken, isn't it possible, probably by using goggle earth and some basic trigonometry, to produce one more estimate that could confirm or not what has been published already ?
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I can see that many estimates on the speed of UA175 have been produced.
Knowing the skyline of NY and the spots from where the few available video were taken, isn't it possible, probably by using goggle earth and some basic trigonometry, to produce one more estimate that could confirm or not what has been published already ?
Knowing the skyline of NY and the spots from where the few available video were taken, isn't it possible, probably by using goggle earth and some basic trigonometry, to produce one more estimate that could confirm or not what has been published already ?
Summary
Using distances taken directly from the video screen, flight 175's groundspeed was calculated to be between 473 and 477 Knots just prior to the collision with the building. Using distances taken from video screen prints, groundspeed at impact of 504 Knots and 507 Knots were calculated. This compares to an impact speed of 510 Knots calculated from radar data in the Radar Data Impact Speed Study (AA11 & UA 175)
NTSB Radar Data Impact Speed Study (9.15mb pdf)Using distances taken directly from the video screen, flight 175's groundspeed was calculated to be between 473 and 477 Knots just prior to the collision with the building. Using distances taken from video screen prints, groundspeed at impact of 504 Knots and 507 Knots were calculated. This compares to an impact speed of 510 Knots calculated from radar data in the Radar Data Impact Speed Study (AA11 & UA 175)
Keep in mind that the aircraft which impacted the south tower had mostly a headwind on it's path. So KTAS is actually a few knots higher than the groundspeeds reported above.
Moderator
Guys - lots of willy waving been going on above. I've deleted a bunch of names as being not overly relevant to Tech Log discussions (if I've missed any please do let me know and I'll have another go).
If the thread doesn't return to a reasonably level-headed discussion I will have to consider removing it to make the problem go away - not something which we do other than very rarely in the forum.
If the thread doesn't return to a reasonably level-headed discussion I will have to consider removing it to make the problem go away - not something which we do other than very rarely in the forum.