Wheels "spinning up" before landing?

DanTheMan

New Member
Wheels \"spinning up\" before landing?

my dad and I were debating this last night...
Are the wheels on airliners "spun up" to speed before landing so there is not such a difference in the speed of the tire in relation to the runway? In other words, so the tire doesn't have to accelerate from 0 to 150 knots at the instant of touchdown.
He claims that they are, but I think that seems too expensive to do and the equipment would be too much of a weight penalty. So who's right?
 

E_Dawg

Moderator
Re: Wheels \"spinning up\" before landing?

I remember reading somewhere that the military tried it experimentally, but the cost / benefit ratio was way off so they just stuck with the way it's always been done.

This is all second hand information (to you it's 3rd) so don't believe any of this
 

Joe

Well-Known Member
Re: Wheels \"spinning up\" before landing?

What about hitting the brakes after takeoff before the gear is retracted? I've seen some photos on airliners.net of what looks like a trail of brake dust coming from the landing gear on departing aircraft.

 

E_Dawg

Moderator
Re: Wheels \"spinning up\" before landing?

I can only speak for the smaller airplanes, but we sometimes do that to reduce the vibration associated with the spinning wheels.
 

IrishSheepdog

Sitting in the median
Re: Wheels \"spinning up\" before landing?

[ QUOTE ]
What about hitting the brakes after takeoff before the gear is retracted? I've seen some photos on airliners.net of what looks like a trail of brake dust coming from the landing gear on departing aircraft.

[/ QUOTE ]

We don't, as far as I know. Maybe some captain's sneak a tap on the pedals to stop the rotation. I know in our systems manual it talks about certain conditions to close a "Flight Idle stop" which keeps us from moving the power levers into the very low pitch range (BETA), and it claims it can take like a minute or more for the wheels to spin down to the equivalent of nine knots. So they must be assuming we don't clamp on the brakes.
 

Derg

Cap, Roci
Staff member
Re: Wheels \"spinning up\" before landing?

[ QUOTE ]
my dad and I were debating this last night...
Are the wheels on airliners "spun up" to speed before landing so there is not such a difference in the speed of the tire in relation to the runway? In other words, so the tire doesn't have to accelerate from 0 to 150 knots at the instant of touchdown.
He claims that they are, but I think that seems too expensive to do and the equipment would be too much of a weight penalty. So who's right?

[/ QUOTE ]

You're right. But if he's paying your rent and/or tuition he's right.
 

Derg

Cap, Roci
Staff member
Re: Wheels \"spinning up\" before landing?

[ QUOTE ]
What about hitting the brakes after takeoff before the gear is retracted? I've seen some photos on airliners.net of what looks like a trail of brake dust coming from the landing gear on departing aircraft.


[/ QUOTE ]

Not on any transport-category aircraft I've flown (Beech 1900/B-727/B-737/MD-88/MD-90)

Some guy in college was teaching that we should lightly tap the breaks before retracting the gear, but I've never seen one iota of proof, guidance or procedure anywhere that would suggest doing such.
 

MikeD

Administrator
Staff member
Re: Wheels \"spinning up\" before landing?

[ QUOTE ]
I know in our systems manual it talks about certain conditions to close a "Flight Idle stop" which keeps us from moving the power levers into the very low pitch range (BETA), .

[/ QUOTE ]

That sucks. Time a landing good enough to where in the flare, you retard to BETA and it occurs just as the mains touchdown for the ultimate short-field landing. Don't reccommend it with pax (one commuter crashed a number of years ago trying it...too early) but in the Caravan it was interesting....

Another situation where timing is everything......
 

A300Capt

Freight Dawg
Re: Wheels \"spinning up\" before landing?

On transport category aircraft, the main gear brakes are automatically applied when you raise the gear handle. The nose wheels hit a snubber to slow their rotation.
 

Derg

Cap, Roci
Staff member
Re: Wheels \"spinning up\" before landing?

[ QUOTE ]
On transport category aircraft, the main gear brakes are automatically applied when you raise the gear handle. The nose wheels hit a snubber to slow their rotation.

[/ QUOTE ]

You know, now I think I remember reading that somewhere.

Sheesh, there's always former check airman lurking around!
 

IrishSheepdog

Sitting in the median
Re: Wheels \"spinning up\" before landing?

[ QUOTE ]
On transport category aircraft, the main gear brakes are automatically applied when you raise the gear handle. The nose wheels hit a snubber to slow their rotation.

[/ QUOTE ]

I'll have to check if our aircraft have this. Probably not, we aren't that "advanced."
 

IrishSheepdog

Sitting in the median
Re: Wheels \"spinning up\" before landing?

[ QUOTE ]
[ QUOTE ]
I know in our systems manual it talks about certain conditions to close a "Flight Idle stop" which keeps us from moving the power levers into the very low pitch range (BETA), .

[/ QUOTE ]

That sucks. Time a landing good enough to where in the flare, you retard to BETA and it occurs just as the mains touchdown for the ultimate short-field landing. Don't reccommend it with pax (one commuter crashed a number of years ago trying it...too early) but in the Caravan it was interesting....

Another situation where timing is everything......

[/ QUOTE ]

Well we do have a FI Stop release knob that mechanically opens it if it's closed... but I won't be going and trying that, EVER.
 

alphaspeed

New Member
Re: Wheels \"spinning up\" before landing?

[ QUOTE ]
On transport category aircraft, the main gear brakes are automatically applied when you raise the gear handle. The nose wheels hit a snubber to slow their rotation.

[/ QUOTE ]

I agree. The brakes are applied by the gear sequencing valve before the struts are moved. The basic sequence would be something like: open doors, unlock the downlocks, apply the brakes, retract the gear, close the doors, then apply the uplocks. Funny thing, when I went to E120 school twelve years ago, we had to learn how to build the flippin gear, but about all we are taught about the DC9/MD890 is how to get it down if the normal procedure doesn't work. Bigger is better!

regards,
Alphaspeed
 

aloft

New Member
Re: Wheels \"spinning up\" before landing?

[ QUOTE ]
I've seen some photos on airliners.net of what looks like a trail of brake dust coming from the landing gear on departing aircraft.


[/ QUOTE ]Accumulations from the previous landing, maybe?
 

stuckingfk

Well-Known Member
Re: Wheels \"spinning up\" before landing?

[ QUOTE ]
FlyChicago who do you fly for?

[/ QUOTE ]

Kostcoguy, you call yourself a JC Pro and you don't know who he works for? Where the heck have you been? Plus, I a simple two second search would reveal who FlyChicaga works for.


Dang FlyChicaga, I took to long to type this reply. Kostcoguy, I forgot the sarcastic tags, I am just playin around.
 

EatSleepFly

Well-Known Member
Re: Wheels \"spinning up\" before landing?

Yeah, how the heck do you change your title anyways? Or can only the bosses do that?
 
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