The front end of Jumbos
Thread Starter
Join Date: Jun 2006
Location: UK
Posts: 152
Likes: 0
Received 0 Likes
on
0 Posts
You might at least get my bloody name right before being rude to me.
Anyway --if you are thinking of a Goldfish at a depth of 4 inches of course it would be difficult to see any forward motion but how can you be so certain that there is none? Eh? Eh? Go on Eh?
Anyway --if you are thinking of a Goldfish at a depth of 4 inches of course it would be difficult to see any forward motion but how can you be so certain that there is none? Eh? Eh? Go on Eh?
Paxing All Over The World
Back to the point about what speed that the venerable lady can get to and she really can move ... a friend of mine spoke about when he was a 'boy pilot' (No.3) on the 744 and I quote almost verbatim but no clues as to when and where this event took place!
During a quiet period, one long night when the Cpt was sleeping, the No.2 decided to see what they could get and started to wind her up. My friend said that by increasing slowly (and taking advantage of a tailwind of around 135kts) they got the 400 to M 0.896. He said that the auto on the GE donkeys was lazy and the A/C would overspeed slightly. They had .88 selected and it started rumbling slightly and the speed was touching .90, so they wound her back for fear that the unusual feedback from the airframe might wake up the 'old man' who was in the bunk and he would not be quite so amused by it!
I understand that the co-pilot was an ex-fast jet boy (the little ones with the really point noses!) and that they achieved a ground speed of about 675kts. Not bad for 400 tons with a blunt nose.
During a quiet period, one long night when the Cpt was sleeping, the No.2 decided to see what they could get and started to wind her up. My friend said that by increasing slowly (and taking advantage of a tailwind of around 135kts) they got the 400 to M 0.896. He said that the auto on the GE donkeys was lazy and the A/C would overspeed slightly. They had .88 selected and it started rumbling slightly and the speed was touching .90, so they wound her back for fear that the unusual feedback from the airframe might wake up the 'old man' who was in the bunk and he would not be quite so amused by it!
I understand that the co-pilot was an ex-fast jet boy (the little ones with the really point noses!) and that they achieved a ground speed of about 675kts. Not bad for 400 tons with a blunt nose.
Join Date: Aug 2008
Location: UK
Posts: 203
Likes: 0
Received 0 Likes
on
0 Posts
Apologies, i intended to be rude to the theory you had heard, not to you. And I apologise for getting your nam ewrong.
it's still boll*cks though
The reason I know is because i can disprove the theory mathematically.
it's still boll*cks though
The reason I know is because i can disprove the theory mathematically.
Warning Toxic!
Disgusted of Tunbridge
Disgusted of Tunbridge
Join Date: Jan 2005
Location: Hampshire, UK
Posts: 4,011
Likes: 0
Received 0 Likes
on
0 Posts
Paxboy, the wind only affects the groundspeed. It makes no difference to your Mach number. It a 747 cruising at M.86 and a jetstream tailwind across the Atlantic of over 200kts, we regularly would exceed 700kts groundspeed by a large margin. Back in the old days on VC10 conversions when we used to do training flights out of Shannon, some of the details were high speed runs. We would get the old girl up to M.93 with high speed buffet. Apparently watching the fin and tailplane through the periscope was a bizarre and frightening experience, moreso when watching Dutch Rolls with the aeroplane swinging into 90 degree banks either side. I have also done stalling stick push checks on a VC10. I'd had enough when the airspeed was 95 kts and angle of attack over 15 degrees. I do not enjoy that sort of thing. With years of 747 operating experience, my sense was the 747 envelope would easily match the VC10.
This is all so simple.
If it were slim and visually streamlined, the ground wouldn't repel it so much just because it's ugly, and therefore it's rate of climb would be less, and hence the aircraft over all would be slower.
The repulsion effect due to ugliness is of course countered on descent by the aircraft's desire to descend because it is after all rather heavy and would prefer to sit in a single place on the ground and do nothing at all.
This is well demonstrated by the relatively more attractive airbus that is of course nowhere near as fast.
If it were slim and visually streamlined, the ground wouldn't repel it so much just because it's ugly, and therefore it's rate of climb would be less, and hence the aircraft over all would be slower.
The repulsion effect due to ugliness is of course countered on descent by the aircraft's desire to descend because it is after all rather heavy and would prefer to sit in a single place on the ground and do nothing at all.
This is well demonstrated by the relatively more attractive airbus that is of course nowhere near as fast.
Paxing All Over The World
Indeed Rainboe, just me mixing in my words with those of my friend so not the best result. However, it was the info about the M.89/.90 that I wanted to add to the thread, given where it started.
Your stories of the VC10 are staggering and am very glad not to have been onboard! My first flight was on a VC10 and I think that she has the finest of lines, which were so beautifully set off by the classic BOAC paint scheme.
Your stories of the VC10 are staggering and am very glad not to have been onboard! My first flight was on a VC10 and I think that she has the finest of lines, which were so beautifully set off by the classic BOAC paint scheme.
Join Date: Feb 2009
Location: UK
Posts: 262
Likes: 0
Received 0 Likes
on
0 Posts
Thank goodness it is blunt up front - gives so much more room between 1A(me) and 1K(her indoors) so at least I get some sleep without being elbowed on a long haul overnight flight.
Join Date: Aug 2008
Location: UK
Posts: 203
Likes: 0
Received 0 Likes
on
0 Posts
I will try Tightslot, but this forum is very short of mathmatical symbology - I blame the mods
Let us say that a between 0 and amax represents every point on the boundary of the shape.
then fx(a) represents its x coordinate and fy(a) represents its y coordinate. Then the angle of the shape at that point is
(dfx/dfa)/(dfy/dfa)
Now the presssue on each point is the same, let us say that the pressure is P. therefore the a force of PdA (should be a delta sign but we don't have one) is applied at that point, orthogonally to the contour, i.e.
(dfx/dfa)/(dfy/dfa) + pi/2 (we don't have pi symbol either and I am assuming radians and that I have chosen x and y orinettaions correctly so that it is a + not a - in that last bit)
Do you really want me to continue?
Let us say that a between 0 and amax represents every point on the boundary of the shape.
then fx(a) represents its x coordinate and fy(a) represents its y coordinate. Then the angle of the shape at that point is
(dfx/dfa)/(dfy/dfa)
Now the presssue on each point is the same, let us say that the pressure is P. therefore the a force of PdA (should be a delta sign but we don't have one) is applied at that point, orthogonally to the contour, i.e.
(dfx/dfa)/(dfy/dfa) + pi/2 (we don't have pi symbol either and I am assuming radians and that I have chosen x and y orinettaions correctly so that it is a + not a - in that last bit)
Do you really want me to continue?
