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Buff crosswind crab taxi

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Buff crosswind crab taxi

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Old 4th Sep 2023, 01:53
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Originally Posted by 757Bob
I’m an old BUFF driver from the ‘70’s. In that time frame we were restricted to airfield with 300 ft. width runways. The crosswind crab system was never contemplated as an aid to turning sharp corners, or taxiway maneuvering, but permitted us to land in 45kt direct crosswinds. The crab setting is precomputed and applied when aligned for takeoff, and removed when slowed to taxi speed after rollout. I had a copilot apply the setting in the wrong direction once. He saw his error, and cranked it all the way the other way while we were rolling. A thrilling low speed rudder dance ensued, similar to the video.
Were there any issues with compressor stalls on the downwind wing/engines?
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Old 4th Sep 2023, 06:42
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Originally Posted by Jhieminga
So what bit of the airframe needs to be on the centreline? Not the flightdeck I guess.... that might be the challenge in landing like this.
Apologies if I'm teaching you to suck eggs but to some degree (SWIDT) it's much the same, at least until the actual de-crab, when flying anything long bodied on an approach with the drift on. You fly down the approach with the flightdeck tracking offset to the upwind side of the centreline.

On those if you've got it right then as you flare and push the drift off the aircraft yaws and the flightdeck returns to the centreline..I'm guessing for the Buff guys they flare and accept the offset remains on touchdown

Last edited by wiggy; 4th Sep 2023 at 07:19.
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Old 4th Sep 2023, 07:06
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Crosswind take-off…..

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Old 4th Sep 2023, 08:18
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Originally Posted by wiggy
Apologies if I'm teaching you to suck eggs but to some degree (SWIDT) it's much the same, at least until the actual de-crab, when flying anything long bodied on an approach with the drift on. You fly down the approach with the flightdeck tracking offset to the upwind side of the centreline.

On those if you've got it right then as you flare and push the drift off the aircraft yaws and the flightdeck returns to the centreline..I'm guessing for the Buff guys they flare and accept the offset remains on touchdown
No need to apologise and thanks for the clarification. I'm strictly a small airframe driver and I had forgotten about the similarity to a long-bodied airliner while crabbing. Makes sense now.

As for rotation on a BUFF, the arm between CG and rear wheel set is very much larger than on a regularly geared airliner/military type, requiring a significant downforce from the tail. One more reason for the built-in angle of incidence on the wing as you would never be able to achieve the same rotation with this size tail as on a civil airliner.
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Old 4th Sep 2023, 08:34
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Nice video of how the a B-52 wing incidence works during landing.


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Old 4th Sep 2023, 11:00
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This helps explains the B-52's remarkable range -- it flies downhill the entire way!

Originally Posted by ORAC


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Old 4th Sep 2023, 12:47
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Originally Posted by DaveReidUK
Is that gauge anything like the Fortunate Son switch?
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Old 4th Sep 2023, 17:03
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BUFF takeoff and landing

Originally Posted by West Coast
Were there any issues with compressor stalls on the downwind wing/engines?
The crab angle, even in a strong crosswind, isn’t enough to induce compressor stalls. The J-57/TF-33 (depending on aircraft model) engines were straight turbojet or low bypass turbofan. Very rugged.
With regard to takeoff and landing characteristics, because of the wing incidence angle, the airplane would try to fly off tail end first if you didn’t apply back pressure at VR.
As you approached the flare for landing, if you were trimmed for approach speed, you’d run out of up elevator authority trying to flare. Trimming in the flare is required to keep from hitting front trucks first. ‘Getting a nose gear’ results in a dramatic bounce. Trying to salvage it often produces a serious PIO. Go around definitely recommended.
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Old 5th Sep 2023, 16:26
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I flew with a guy off C5 Galaxies. He said the early ones had a crabbing landing gear for cross winds, but after an event when one landed with the wrong way selected, the system was disabled, as the de-crab was no big issue.
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Old 5th Sep 2023, 16:48
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Originally Posted by dixi188
I flew with a guy off C5 Galaxies. He said the early ones had a crabbing landing gear for cross winds, but after an event when one landed with the wrong way selected, the system was disabled, as the de-crab was no big issue.
I think the rearmost MLG leg is still able to castor.
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Old 6th Sep 2023, 08:06
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At C-5 masses you don't need a cross wind gear, it just beats the runway into submission.
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Old 6th Sep 2023, 08:13
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Originally Posted by DaveReidUK
Ok, I’ll bite

You posted the picture, care to explain ?
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Old 6th Sep 2023, 09:31
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Simply illustrating how vocabulary changes over time.
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Old 7th Sep 2023, 05:21
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Originally Posted by DaveReidUK
Simply illustrating how vocabulary changes over time.

You are ducking the question, do you know what this instrument is for then ?!
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Old 7th Sep 2023, 08:37
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Originally Posted by stilton
You are ducking the question, do you know what this instrument is for then ?!
Rad alt.
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Old 7th Sep 2023, 13:58
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Have a look at 1:18 in the video on this page https://www.gettyimages.nl/detail/vi...tage/816064990
It shows an Autoland sequence on a HS Trident, including the Rad Alt indicator shown above.
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Old 7th Sep 2023, 17:40
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I believe the picture was posted in response to Stillton in #10 and in particular the use of the term “kick-off Drift”, rather than reference to the function of the instrument itself in the Trident blind landing system.

Terminology and the use of words changes over the years.
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Old 7th Sep 2023, 17:46
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Originally Posted by ORAC
I believe the picture was posted in response to Stillton in #10 and in particular the use of the term “kick-off Drift”, rather than reference to the function of the instrument itself in the Trident blind landing system.

Terminology and the use of words changes over the years.
Yes, sorry I couldn't resist.
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Old 8th Sep 2023, 05:17
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Originally Posted by DaveReidUK
Yes, sorry I couldn't resist.
Lovely old film


Terminology has changed, a pilot shouldn’t be told to ‘kick off drift’ any more than he or she should be told to flare by yanking on the yoke
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Old 8th Sep 2023, 05:33
  #40 (permalink)  

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Surely on a B-52 there is always a yank on the yoke….
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