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Has Any Body Flown On A 747 At Full Speed?  
User currently offline747400sp From United States of America, joined Aug 2003, 3757 posts, RR: 2
Posted (9 years 4 months 2 weeks 4 days 19 hours ago) and read 11322 times:

I was told, that when a Boeing 747 is pushed to it's full compacity of speed in flight, it make for a ruff and uncomfortable ride. I just wanted to know have anybody ever flown on a 747 during a full power run in flight to confirm this.

Thank You

25 replies: All unread, showing first 25:
 
User currently offlineSPREE34 From United States of America, joined Jun 2004, 2264 posts, RR: 9
Reply 1, posted (9 years 4 months 2 weeks 4 days 18 hours ago) and read 11224 times:

Nope.

I rode an L1011 at mach.88 and it was perfectly smooth.



I don't understand everything I don't know about this.
User currently offlineDLKAPA From , joined Dec 1969, posts, RR:
Reply 2, posted (9 years 4 months 2 weeks 4 days 18 hours ago) and read 11213 times:

During the 747 test program, they did high power dives, the airspeed indicators read mach .99, it can be said that parts of the plane (the top of the wing where air moves faster) probably exceeded the sound barrier for a brief period.

User currently offlineSpacecadet From United States of America, joined Sep 2001, 3671 posts, RR: 12
Reply 3, posted (9 years 4 months 2 weeks 4 days 17 hours ago) and read 11102 times:

I was told, that when a Boeing 747 is pushed to it's full compacity of speed in flight, it make for a ruff and uncomfortable ride. I just wanted to know have anybody ever flown on a 747 during a full power run in flight to confirm this.

Not really sure what you mean by this. I have flown on a 747 at Mach 0.92, which is its maximum cruising speed. We had left the gate late and were making up time. The flight was fine.

No airplane ever cruises at "full power". Leave the engines running at full power after takeoff and either the engines or the airplane will eventually rip themselves apart, depending on where the stress points are. All commercial airplanes are powerful enough to speed themselves well beyond their maximum cruising speed. (Edit: I realize this is an extreme over-simplification of what happens in an overspeed condition - there are all sorts of things that happen to an airplane in extreme and prolonged overspeed.)

If you were in *any* airplane that was cruising at full power for very long, you'd be in for a pretty rough and uncomfortable ride. And you'd more than likely end up dead.

[Edited 2005-08-07 06:11:57]

[Edited 2005-08-07 06:12:49]


I'm tired of being a wanna-be league bowler. I wanna be a league bowler!
User currently offlinePWM2TXLHopper From United States of America, joined Jan 2004, 1360 posts, RR: 1
Reply 4, posted (9 years 4 months 2 weeks 4 days 17 hours ago) and read 11102 times:

Quoting 747400sp (Thread starter):

I'm sure there have been hundreds of thousands of HR's transported on 747s that reach full speed during the cruise portion of their flight home to their final resting place.


User currently offlineHT From Germany, joined May 2005, 6525 posts, RR: 23
Reply 5, posted (9 years 4 months 2 weeks 4 days 10 hours ago) and read 10843 times:

Quoting PWM2TXLHopper (Reply 4):
I'm sure there have been hundreds of thousands of HR's transported on 747s that reach full speed during the cruise portion of their flight home to their final resting place.

Sorry, I´m not getting the sense of this statement  Confused



Carpe diem ! Life is too short to waste your time ! Keep in mind, that today is the first day of the rest of your life !
User currently offlineCxsjr From , joined Dec 1969, posts, RR:
Reply 6, posted (9 years 4 months 2 weeks 4 days 9 hours ago) and read 10730 times:

I've still never gotten to grips with the difference between ground speed, air speed, knots, mph etc etc.

If you watch the flight programme on IFE, what does that show your speed in?

I flew back from BOS-LHR on a BA 772 - we flew at FL410 with tail winds of 150+ mph and completed the journey in 5h 40 mins - I'm sure I remember the speed thing on the telly showing 703 mph??!! (BTW, the outward journey on a BA 742 took 8h 15 mins because of the same winds!)

Comments?


User currently offlineScott0305 From United Kingdom, joined May 2005, 196 posts, RR: 0
Reply 7, posted (9 years 4 months 2 weeks 4 days 9 hours ago) and read 10666 times:

Cxsjr - The IFE shows ground speed so the tail (or head) wind component is added to the airspeed to show the actual speed across the ground.

User currently offlineEADC8 From United States of America, joined Mar 2005, 141 posts, RR: 0
Reply 8, posted (9 years 4 months 2 weeks 4 days 9 hours ago) and read 10648 times:

I once flew LAX - JFK on a FF 747 in 4h 2m. At one point the display showed our ground speed at 718mph. I don't know how that would translate into mach speed, but I would imagine it had to be way up there. Just for the record, the flight was perfectly smooth.


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User currently offlineIkramerica From United States of America, joined May 2005, 21582 posts, RR: 59
Reply 9, posted (9 years 4 months 2 weeks 4 days 7 hours ago) and read 10510 times:

Quoting EADC8 (Reply 8):

probably just a strong winter wind there. you can get really amazing times in winter to MIA from LAX, too.

But remember, ground speed doesn't equal "mach" speed. Mach speed is the speed of the jet through the air you are in, varies with air density, altitude and wind speed etc. Even if you have a ground speed over still air mach speed at 0 elevation, you are still not traveling faster than the speed of sound in the air around you at 41,000 feet with a 150knot wind, and that's all that matters.



Of all the things to worry about... the Wookie has no pants.
User currently offlineDLKAPA From , joined Dec 1969, posts, RR:
Reply 10, posted (9 years 4 months 2 weeks 4 days 7 hours ago) and read 10482 times:

Quoting Cxsjr (Reply 6):
I've still never gotten to grips with the difference between ground speed, air speed, knots, mph etc etc.

Ground Speed: The speed of the aircraft across the earth, the most literal form of "Speed" in that if you were to bounce a radar gun from a stationary object to an aircraft in flight the speed registered would be the aircrafts ground speed.

Air Speed: The actual measurement of speed in flight, measured by the pitot tubes (I think, that or static ports, but I really think its the pitot tubes), actually it measures Ram Air pressure, which is most literally the force of the air molecules as they hit the airplane. If you have a 250 KIAS but a 150kt tail wind, your ground speed will be 400 kts, which brings me to

Knots: A "Knot" is basically One Nautical Mile per hour, and a Nautical Mile is 1 and 1/8th of a statute mile (The form we use).


User currently offlineUAcsOKC From United States of America, joined Dec 2004, 107 posts, RR: 1
Reply 11, posted (9 years 4 months 2 weeks 4 days 5 hours ago) and read 10166 times:

Quoting HT (Reply 5):
Quoting PWM2TXLHopper (Reply 4):
I'm sure there have been hundreds of thousands of HR's transported on 747s that reach full speed during the cruise portion of their flight home to their final resting place.

Sorry, I´m not getting the sense of this statement

Meaning if they cruised at full speed, they'd be dead.



I love the rumble of a 727 takeoff in the morning!
User currently offlineKC135TopBoom From United States of America, joined Jan 2005, 12181 posts, RR: 51
Reply 12, posted (9 years 4 months 2 weeks 4 days 5 hours ago) and read 10004 times:

Cruising in any airplane at it's maximum cruise speed will not ever be noticed by the passengers. The airplane is designed to do that. BTW, ground speed has nothing to do with max mach number. That is a function of the combination of airspeed (even less that max.) and the winds at altitude.

I have flown the KC-135A a lot at maximum mach number (.95M). but most of the time we fly high speed, it is KIAS, as flying mach number means altitude changes. You cannot tell the difference between max cruise and any other cruise speed.

There is something called "high speed buffet" that all airplanes will encounter at or above their designed max airspeed.


User currently offlineDstefanc From United States of America, joined Dec 2001, 63 posts, RR: 3
Reply 13, posted (9 years 4 months 2 weeks 4 days 5 hours ago) and read 9887 times:

Quoting EADC8 (Reply 8):
At one point the display showed our ground speed at 718mph. I don't know how that would translate into Mach speed, but I would imagine it had to be way up there.

It is very easy for You to check the Mach You were flying at as long as You know what altitude You were flying at. The equation is

M = V / a

where M = Mach,
V = Velocity (in this case 718 mph), and
a = speed of sound

To calculate the speed of sound You can use the following equation:

a = sqrt(gamma * R * T),

where gamma = ratio of specific heats = 1.4 for air
**it's a thermodynamics property
R = universal gas constant
T = surrounding temperature (this value is easy to obtain, because there are published tables of air temperature at each altitude: this is where Your knowledge of the flight level would come in handy). If You know what altitude You were flying at, then that could be translated to what temperature You were flying at. Use this as a source:



So to sum up, the equation is as follows:

M = V / sqrt(gamma * R * T)

**make sure You pay attention to the units, otherwise Your answer won't make sense - by the way, the units have to cancel out, since M is unitless.

Damian


User currently offlineDan2002 From United States of America, joined Dec 2002, 2055 posts, RR: 5
Reply 14, posted (9 years 4 months 2 weeks 4 days 5 hours ago) and read 9856 times:

Quoting HT (Reply 5):

Sorry, I´m not getting the sense of this statement Confused

The title of the thread was Any Body Flown on a 747 at full speed. He is talking about human remains, ie bodies being transported below deck. It was a pun.

-Dan



A guy asks 'What's Punk?'. I kick over a trash can and its punk. He knocks over a trash can and its trendy.
User currently offlineCORULEZ05 From , joined Dec 1969, posts, RR:
Reply 15, posted (9 years 4 months 2 weeks 4 days 4 hours ago) and read 9311 times:

Quoting Dan2002 (Reply 14):
The title of the thread was Any Body Flown on a 747 at full speed. He is talking about human remains, ie bodies being transported below deck. It was a pun.

no he's not.....look at the thread starter:

Quoting 747400sp (Thread starter):
I just wanted to know have anybody ever flown on a 747 during a full power run in flight to confirm this.

He just put a space in the thread topic line but later fixed it in the thread starter.......pretty obvious.


User currently offlineAeroWeanie From United States of America, joined Dec 2004, 1610 posts, RR: 52
Reply 16, posted (9 years 4 months 2 weeks 4 days 4 hours ago) and read 9275 times:
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Quoting DLKAPA (Reply 2):
During the 747 test program, they did high power dives, the airspeed indicators read mach .99, it can be said that parts of the plane (the top of the wing where air moves faster) probably exceeded the sound barrier for a brief period.

In cruise, some regions of a 747 have air traveling faster than the speed of sound (as do most jet airliners). This flow is terminated in shock waves. There is a shock on the wing of the 747 in cruise, a small shock between the nacelle and wing and another in the junction of the horizontal and vertical tail. I have actually seen the first two while traveling on a 747 (I know about the third from CFD work I have done). If the sun is in the right position, you will notice that what you are looking at is split, kind of like looking at something through a clear glass of water, right at the water's edge. This is because you are looking through the shock wave.


User currently offlineHT From Germany, joined May 2005, 6525 posts, RR: 23
Reply 17, posted (9 years 4 months 2 weeks 4 days 3 hours ago) and read 8860 times:

Quoting UAcsOKC (Reply 11):
Meaning if they cruised at full speed, they'd be dead.

&

Quoting Dan2002 (Reply 14):
Quoting HT (Reply 5):
Sorry, I´m not getting the sense of this statement {Confused}

The title of the thread was Any Body Flown on a 747 at full speed. He is talking about human remains, ie bodies being transported below deck. It was a pun.

Tnx for updating me !
I didn´t catch the typing error in "any body" and the subsequent pun built around it by PWM2TXLHopper ...
-HT



Carpe diem ! Life is too short to waste your time ! Keep in mind, that today is the first day of the rest of your life !
User currently offlineVikkyvik From United States of America, joined Jul 2003, 10338 posts, RR: 26
Reply 18, posted (9 years 4 months 2 weeks 4 days 3 hours ago) and read 8836 times:

Quoting DLKAPA (Reply 10):
If you have a 250 KIAS but a 150kt tail wind, your ground speed will be 400 kts, which brings me to

Careful there. Ground speed = wind + KTAS (true airspeed), not KIAS (indicated airpseed)

Indicated Airspeed is not the actual speed of the aircraft through the air.

~Vik



How can I be an admiral without my cap??!
User currently offline4holer From United States of America, joined Feb 2002, 3047 posts, RR: 9
Reply 19, posted (9 years 4 months 2 weeks 4 days 3 hours ago) and read 8732 times:

OK, so we've figured out "any body", now lets work on "ruff" and "compacity"!  Wink

My question is if the 747 is the only airliner still flying that you can see the shock wave. I know its cruise speed can be higher than the newer models and maybe the newer jets don't go fast enough for the shock waves?



Ghosts appear and fade away.....................
User currently offlineIL96M From United Kingdom, joined Jun 2005, 139 posts, RR: 0
Reply 20, posted (9 years 4 months 2 weeks 4 days 2 hours ago) and read 8204 times:

Quoting AeroWeanie (Reply 16):
I have actually seen the first two while traveling on a 747

I have seen this also! So that's what it is...

I also heard that areas around the flight deck windows of the 747 are supesonic too.


User currently offlineUSAF757300 From , joined Dec 1969, posts, RR:
Reply 21, posted (9 years 4 months 2 weeks 4 days 2 hours ago) and read 8061 times:

My dad was flying IAD-MUC on a UA T7 and he said that they got up to 692 MPH. It said on the IFE.

User currently offlineVS11 From United States of America, joined Jul 2001, 1111 posts, RR: 0
Reply 22, posted (9 years 4 months 2 weeks 4 days 2 hours ago) and read 8033 times:

Quoting 4holer (Reply 19):
OK, so we've figured out "any body", now lets work on "ruff" and "compacity"!

That is hilarious!!!  Smile


User currently offlineBhmbaglock From United States of America, joined Jul 2005, 2698 posts, RR: 5
Reply 23, posted (9 years 4 months 2 weeks 3 days 23 hours ago) and read 6872 times:

Quoting Dstefanc (Reply 13):
Quoting EADC8 (Reply 8):
At one point the display showed our ground speed at 718mph. I don't know how that would translate into Mach speed, but I would imagine it had to be way up there.

It is very easy for You to check the Mach You were flying at as long as You know what altitude You were flying at. The equation is

M = V / a

where M = Mach,

It might also be useful to know the wind at altitude. I'm betting more on high tailwind than high Mach for 718 mph particularly for a W-E route like LAX-JFK.



Where are all of my respected members going?
User currently onlineStarlionblue From Greenland, joined Feb 2004, 17174 posts, RR: 66
Reply 24, posted (9 years 4 months 2 weeks 3 days 23 hours ago) and read 6825 times:

Quoting DLKAPA (Reply 10):

Knots: A "Knot" is basically One Nautical Mile per hour, and a Nautical Mile is 1 and 1/8th of a statute mile (The form we use).

I'm pretty sure the International Nautical Mile is used by all aviation. This is defined as 1852 metres exactly, which converts to 1.150 779 45 statute miles (exactly) or 6 076.115 49 feet (exactly).

For more: http://en.wikipedia.org/wiki/Nautical_mile



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineEADC8 From United States of America, joined Mar 2005, 141 posts, RR: 0
Reply 25, posted (9 years 4 months 2 weeks 2 days 21 hours ago) and read 6193 times:

Quoting Ikramerica (Reply 9):
probably just a strong winter wind there. you can get really amazing times in winter to MIA from LAX, too.

Yes. It most certainly was. The flight date was 1/29/1996. I should have been a little clearer in my post. I wasn't trying to insinuate that we were flying "balls to the wall". Our ground speed was definitely the result of a very strong tail wind.



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