732: Viewed from behind

[Q4NVS]

Anyone here willing to give a proper Technical Reason for the odd looking 732, when viewed from behind.

For those who have not taxiied behind one, well in short, it looks as if it had been sideswiped by a PUTCO Bus. :eek: The aircraft seems to be crabbing to the left even though it is actually taxiing straight.

Any takers on the reason - I've had someone try to explain something about the Landing Gear, but didn't seem completely convinced...

[putco]

Hey, let's not be so harsh with the Putco word....:ouch: ;)

[Spike from Flyi]

As it was explained to me, when they designed the landing gear, the nose wheel could not be placed on the exact centerline of the keel, and had to be offset; therefore, the aircraft does not sit straight on the centerline of the taxiway, but the wheels are all parallel and not "crabbing". But what do I know? I have a 737 type rating, but no time in the actual aircraft. BTW, this explanation did not come from my instructor in the type training (I don't remember the topic ever coming up.), it came from my first officer when I posed the same question to him one day at O'Hare in Chicago. With that qualification, would anyone care to confirm or dispute?

[Chesty Morgan]

I understand that the main bogeys have about 8 degrees of play in 'em to allow for crosswind landings if you aint straight enough.

Apparently they reset to 'Straight' when the gear next goes up.

[Goldfish Jack]

I always thought it was to offset the torque effect of the rotating beacon on top of theaircraft!

[Vertical_Reference]

Is there any reason why taxi's in Jo'burg crab?

Maybe they share similar reasons. :p

[bafanguy]

I understand that the main bogeys have about 8 degrees of play in 'em to allow for crosswind landings if you aint straight enough.
Apparently they reset to 'Straight' when the gear next goes up.

I'll have whatever Chesty's drinking, make it a double, and step lively while you're at it.

Went into my Boeing ( not a tailored company manual ) B737-2H4 manual, circa 1971, and found no mention of why the crab is there.

It is certainly there.

[Heli_Sticktime]

Anyone got a link to a picture of this, would be interesting for a flingwing pilot to see this

[makeapullup]

From the front and caused by wind (apparently) but still a nice pic.
http://photos.airliners.net/photos/middle/4/8/0/0846084.jpg

[makeapullup]

Some more references (and similar jokes)
http://www.pprune.org/forums/archive/index.php/t-188318.html

[Chesty Morgan]

I'll have whatever Chesty's drinking, make it a double, and step lively while you're at it.
Went into my Boeing ( not a tailored company manual ) B737-2H4 manual, circa 1971, and found no mention of why the crab is there.
It is certainly there.

Mentioned to me by a 737 typed pilot who has got a brain the size of a planet. He probably knows.

[FlingWingKing]

I understand that the main bogeys have about 8 degrees of play in 'em to allow for crosswind landings if you aint straight enough.

Apparently they reset to 'Straight' when the gear next goes up.

This is exaclty what was explained to me by a training captain. There is a bit of "play" in the main landing gear to allow for x-wind situations. Look at a 732 taxing next time u are behind it, the nose should be pointing upwind, causing it to "crab" taxi left/right depending on x-wind conditions.

[Jelly Doughnut]

Nothing in my manuals or the Boeing flight crew training manual, but found the following on www.b737.org.uk

One of the peculiarities of the 737 is that it invariably appears to crab when taxying. Theories for this include: A slightly castoring main gear to increase the crosswind capability; Play in the scissor link pins; Weather-cocking into any crosswind impinging on the fin; Torque reaction from the anti-collision light !!! Engineers will tell you that is due to the main gear having a couple of degrees of play due to the shimmy dampers

[bafanguy]

Mentioned to me by a 737 typed pilot who has got a brain the size of a planet. He probably knows.

Chesty,

Just "funnin'" ya. That website is really good. But they talk in terms of "...theories..." for the crab. Do the gear, for a fact, have play in them ? If so, it would be such a basic, and unusual, facet of the design that one would expect to see Boeing mention it in their own manuals.

All these airplanes land in x-winds...and have shimmy dampers. What would require such an unusual feature for the 737...low-slung engine pods ?

Anyone have a Boeing publication explaining this ?