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B737 x-wind take-off

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B737 x-wind take-off

Old 2nd Jan 2009, 10:58
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For those that preset the aileron. How do you know you are not using too much?
I never did like talking angles[unless absolute limitations] I like to talk of pressure so not really a 'preset' more like a "pre -firm -controlled pressure- because you know" but that's hard to say and not very technical sounding

but as you accelerate before you increase your AOA at Vr you can nevertheless sense a need in the knuckles to either increase or decrease the as the dynamic pressure is affecting the flight controls via the artificial feed back system but I think most pilot are doing this either consciously or unconsciously --also at low speed the flight controls are not sensitive maybe it's all the Afro-Caribbean,Boricua and down south hybrid rhythm I got

PA
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Old 2nd Jan 2009, 11:07
  #42 (permalink)  
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A wing is designed NOT to produce lift on the ground
....but it does when the wing starts lifting above 80 kts!

I take it dad tested smaller types with big spoilers? Spoilers on airliners are not particularly effective, in fact sometimes I think they produce more vibration than drag. I refuse to accept there is ANY appreciable drag below 100kts, and very very minor drag up to 140kts. Remember at 1 division ONLY per 5 kt tailwind, you should never have more than 7 units aileron applied. Anybody who has more is not doing it right.

I positively maintain you cannot 'sense' a wing lifting. You can 'sense' the movement of a wing lifting, no matter how clever a pilot you think you are, in which case it is already physically in the process of lifting. Too late- it is already happening. So you are jockeying with aileron while you are desperately trying to jockey with the rudder to keep centreline? Why not make life easier for yourself? All I was trying to say was 'try it, and form your own opinion'. It's how it used to be done. It worked. Suddenly, because some truly astonishing operators now fly the thing, it is all dumbed down into lawyer-speak. That is how we used to do it, on 400 tonne 747s in hot and high operations on limiting runways. How is it suddenly so dangerous now on an overpowered 737?
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Old 2nd Jan 2009, 11:29
  #43 (permalink)  
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you can nevertheless sense a need in the knuckles to either increase or decrease the as the dynamic pressure is affecting the flight controls via the artificial feed back system but I think most pilot are doing this either consciously or unconsciously --also at low speed the flight controls are not sensitive
Smoke and mirrors! Come on, seriously! You are feeling the wing actually lift. You are not 'sensing' some mysterious force. When you hold something that someone is pushing, (like furniture), you have no idea what force is on it and what it is experiencing until it suddenly jerks on you and moves! You cannot 'sense' any forces in it. Let's get rid of this 'sensing' hurdy-gurdy psychic nonsense! Until that wing starts lifting, you don't 'sense' bugger all!

And we are talking fully powered flight controls here. You are not feeling nowt naturally!
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Old 2nd Jan 2009, 11:37
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I don't even let the stinkin' wing twitch--and I'm an ok pilot nothing special in fact a bit lazy

And we are talking fully powered flight controls here.
yes as I said

either increase or decrease the as the dynamic pressure is affecting the flight controls via the artificial /feel feed back system
what's the ADC for?

yes I added the word 'feel' because I omitted it earlier
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Old 2nd Jan 2009, 11:38
  #45 (permalink)  
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RB - note what I said
to sense minute changes in acceleration and attitude
and I then later used 'sense'. You are just WRONG! Go on - make it a New Year's resolution...........

Incidentally
Too late- it is already happening. So you are jockeying with aileron while you are desperately trying to jockey with the rudder to keep centreline?
- all I can say is you fly your way, if you must, and I fly mine. It has stood me in good stead with the many skills I have needed in my career for the various roles I have undertaken. You really must be absolutely exhausted after a x-wind take-off - and the co-pilot a bag of nerves? I guess you'd need a quick nap en-route to recover?

I do think Chesty summed it up well
but simply feeling and reacting to movement of the aircraft or merely - flying an aeroplane. If the wing begins to lift during the take off simply use enough aileron to stop it and keep the wings level. Just like you do when you're airborne.
Incidentally, Chesty, your dad was not completely right as quoted - many, many a/c have a positive angle of incidence on the wing during the ground roll and so produce both lift and vortices during the roll, they only become significant when the a/c rotates and the lift starts in earnest and the vortex is now not constrained by the ground. Indeed, some a/c (for reasons of geometry) have such a 'rigging angle' that they actually require no pitch change at 'rotate' to leave the ground. What he probably meant was that no wing is REQUIRED to produce lift on the ground until the moment of unstick.
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Old 2nd Jan 2009, 11:48
  #46 (permalink)  
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Too late- it is already happening. So you are jockeying with aileron while you are desperately trying to jockey with the rudder to keep centreline?
Which is why you stop it and is this not what we are doing when we are landing in a crosswind?

I refuse to accept there is ANY appreciable drag below 100kts, and very very minor drag up to 140kts
Well I obviously can't quantify it but it is there and it will affect the performance albeit by a small amount.

Why not make life easier for yourself?
Well, because the easy way isn't always the correct way. Or the safest.

I take it dad tested smaller types with big spoilers?
Generally yes but he has evaluated types from a Gazelle to an A320 and most things inbetween. He also flew the 737 for a number of years.

Edit: BOAC I stand corrected, my fault as it probably got lost in translation!
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Old 2nd Jan 2009, 12:49
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DC-ATE
We were in the overcast at 15T (MSL), terrain ~ 7000 (Colorado Springs area). We DID have engine anit-ice on, but NOT wing. 737 has NO tail de-ice. Boeing said the tail didn't ice. How stupid can you be?!

Anyway, after doing the Clean, and Maneuver stall and revocery, the Landing configuation was next (gear down, 40 flap). I started to feel the elevator buffet before receiving the stick shaker, so called for the recovery procedure: T/O Power (excuse me...thrust), Flaps 15 (that procedure has changed a few times with regard to Flap setting). The "Captain Instructor" criticized me for not "taking it to the stick shaker." I told him I thought the "procedure" was to recognize an impending stall and recover. He said to take it to the stick shaker. Knowing I had sufficient altitude, I agreed and re-did the maneuver. As I started to feel the elevator buffet, I called that to his attention. You could see the stick moving back and forth! He said..."Take it to the Stick Shaker!" I might add that the buffett occured at a higher IAS than previous (more ICE!). Well, the stick shaker did come on and I called for the recovery procedure. He firewalled the throttles (excuse me...thrust levers) and we simply started to go DOWN with no increase in speed. I aksed him if he believed me now that we we starting to stall when I felt the buffett. He was kinda over there frozen not knowing just what was going on. Well, if you've flown the 737 (this was a -200 BTW), you'll know that with increased thrust the nose has a tendency to go up. I waited to see if this "Captain/Instructor" knew what to do. It was obvious he did not so I merely removed his hands from the throttles and pulled the throttles back about half way. The nose came down; speed picked up and I flew out of it. Simple.

I asked him after that if he though we might have some ice. My flying partner and I had both suggested wing anti-ice earlier, but he "knew better!" We flipped on the wing ice light and what do ya know? ICE. About 3 to 4 inches of the nice stuff! So, he calmly turns on the wing ice and we head for the barn. I said what about the tail, knowing there is NO tail anti-ice. He said not to worry because Boeing says the tail doesn't ice on this airplane.

Yes, this incedent was fully reported with NOTHING comming out of it. Wonder why?!?! We lost a 37 at MDW because of airfoil ice but it was never admitted to in the accident report. Why? Because Charlie Fox Dog (the Chicago Fire Department) said there was no ice visible when they got to the crash site. Well, .....the aircraft was on fire!

So.....the "BOOK" isn't always right. There's quite a few people no longer with us because some thought that. Sad.

Enough!
I recently took part in a power off control check on a ferry flight. The elevator had been removed and re-fitted so the rigging had to be checked to make sure the aircraft would be controllable using manual reversion. We had to climb to FL350 and be VMC in daylight to carry out the check and we only carried out some straight and level stuff. I'm amazed that your company allowed stall training in IMC/Icing conditions. I can only speak for the 300 sim which does have a violent pitch up when TOGA is applied but we were instructed to apply full nose down elevator and apply nose down pitch trim until pitch control is recovered. You do see some extreme nose up attitudes but the thrust keeps you flying (provided you're not carrying ice?). I think Boeing suggest rolling the aircraft for extreme nose up attitudes to bring the nose back to the horizon but I would not fancy rolling a stalled aircraft myself. Thanks for taking the trouble to recall the story. I'm glad I don't fly for your company as I don't think I'm brave enough to get through your conversion training! I assume by the 200 reference that this happened some time ago?
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Old 2nd Jan 2009, 13:10
  #48 (permalink)  
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BOAC

Right you are sir. Especially tandem gear A/C. BUFF. The B-52 does NOT
rotate, it levitates. suggestion: Rainboe nor you are wrong. Words have shades of meaning, and can trap professionals and others in meaningless disagreements. Richard Bach may fly differently (sic) than de Havilland or John Boyd, but Physics is physics and in my humble (!) opinion is not subject to nuance. Interpretation? Certainly.

Last edited by airfoilmod; 2nd Jan 2009 at 13:45.
 
Old 2nd Jan 2009, 14:04
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AFM,
glad to see you back posting --I like your viewpoint you are very balanced---


PA
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Old 2nd Jan 2009, 14:23
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"Spoilers on airliners are not particularly effective, in fact sometimes I think they produce more vibration than drag. I refuse to accept there is ANY appreciable drag below 100kts, and very very minor drag up to 140kts."

Guess you're unfamiliar with the DC-9. . AeroMebbe crashed one after emergency descent, as it wouldn't fly with the spoilers still up. I was once SLF just aft of the wing on an MD-80 that was trying to hold at 6K feet after descent toward KLAX. We were getting pre-stall shake until he retracted spoilers. Yes, I've been on big airplane test flights, and know stalls. Ever watch the Horizontal stab of a DC-10 during stall? One of the techs said, "Oooh! Wish I'd never seen that."

In all this discussion, I have seen no mention of fuselage blanking lift on the downwind wing.

GB
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Old 2nd Jan 2009, 14:31
  #51 (permalink)  
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We're talking about spoilers cracked open a small proportion of travel, on one wing, at up to and below 140 kts, rather than full spoiler operation on both sides at 150kts plus. A good rainfall on the fuselage and wings will probably provide more drag!

I have, I think, been fortunate all my flying career in being able to sense minute changes in acceleration and attitude
I was never blessed with razor sharp super-senses and other superpowers! I sure wish I was gifted with some of BOAC's superpowers! I'd settle for the X-ray vision- must have been well fun with the cabin crew! I have to do it the hard way. Plod along....but I enjoy it, even if i only do it by the numbers. Haven't broken anybody yet......except the baggage cart driver at Washington. That was her fault though.

Last edited by Rainboe; 2nd Jan 2009 at 14:55.
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Old 2nd Jan 2009, 14:55
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Everyone on pprune is either 'doing something right' or just damn lucky' how do I know? because they're still here to post

I'm NOT proselytizing but I think the following passages from Ecclesiastes is appropriate

1:3 What profit hath a man of all his labour which he taketh under the sun?
1:4 One generation passeth away, and another generation cometh: but the earth abideth for ever.
1:5 The sun also ariseth, and the sun goeth down, and hasteth to his place where he arose.
1:6 The wind goeth toward the south, and turneth about unto the north; it whirleth about continually, and the wind returneth again according to his circuits.
1:7 All the rivers run into the sea; yet the sea is not full; unto the place from whence the rivers come, thither they return again.
1: 8 All things are full of labour; man cannot utter it: the eye is not satisfied with seeing, nor the ear filled with hearing.
1:9 The thing that hath been, it is that which shall be; and that which is done is that which shall be done: and there is no new thing under the sun.
1:10 Is there any thing whereof it may be said, See, this is new? it hath been already of old time, which was before us.
1:11 There is no remembrance of former things; neither shall there be any remembrance of things that are to come with those that shall come after.
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Old 2nd Jan 2009, 14:59
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1.12 Yo bro', give a man a fish and he is fed for one day. Teach him how to fish and he can drink beer all day.

Wossit got to do with Xwind take-off, PA?
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Old 2nd Jan 2009, 15:15
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Wossit got to do with Xwind take-off, PA?

all of flying life etc.


by PA: exactly what Davies says something like it's better to stop a wing from lifting then to try and put it down then he says [basically] watch out with the spoilers and don't be too active on the wheel

by Check Board: Advocates of presetting the aileron (and I am one) are not saying anything different - simply suggesting that using experience to anticipate a requirement is better than attempting to react to a requirement.
by Rainboe We're talking about spoilers cracked open a small proportion of travel, on one wing, at up to and below 140 kts, rather than full spoiler operation on both sides at 150kts plus. A good rainfall on the fuselage and wings will probably provide more drag!
by Airfoilmod Each may fly differently (sic) than de Havilland or John Boyd, but Physics is physics and in my humble (!) opinion is not subject to nuance. Interpretation? Certainly.


1: 8 All things are full of labour; man cannot utter it: the eye is not satisfied with seeing, nor the ear filled with hearing.
1:9 The thing that hath been, it is that which shall be; and that which is done is that which shall be done: and there is no new thing under the sun.
1:10 Is there any thing whereof it may be said, See, this is new? it hath been already of old time, which was before us.
1:11 There is no remembrance of former things; neither shall there be any remembrance of things that are to come with those that shall come after.
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Old 2nd Jan 2009, 15:41
  #55 (permalink)  
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Drift

Not Of Thread but of Pride, which goeth before the excursion into the weeds of thy noble air machine, blocking her true relationship with the wind that carries her aloft.

Humility is the understanding of one's true self. Those who aspire to wisdom generally make the least noise.

Howdy PA, and an elegant perspective of flight you offer. AF
 
Old 2nd Jan 2009, 16:16
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CHfour -
"I'm glad I don't fly for your company as I don't think I'm brave enough to get through your conversion training! I assume by the 200 reference that this happened some time ago?"

You have to realize that took place in 1969! There is no transition training in the actual aircraft any more. Hasn't been for many, many years.

Anything further on this, I suggest a new thread as we're way off topic.
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