Winter flying with retractable gear?

Robert M. Gary wrote:


There are two things here. Tapping the brakes is something started in
WWII because a B-17 would tip over when the gear come up if the wheels
were spinning (imagine the gyro action happening on those big wheels).

Myth.

First, the wheels are NOT that big compared to the weight of the aircraft.

Second, the B-17 wheels are retracted along their plane of rotation.
They swing forward nestling in the inboard engine nacells. If you
land one gear up, it will roll on the retracted wheels (with other parts
of the aircraft scraping, however).

On Tue, 12 Oct 2004 10:00:16 -0400, Ron Natalie
wrote:

Teacherjh wrote:


I was taught to tap the brakes to stop the wheels from spinning before tucking
them away. (spinning tires bulge out a bit, or so I was told) I confess I've
never actually looked down (sometimes I fly a cutlass) to see how long it takes
them to stop on their own.


To me that sounds like a good way to have the brakes freeze.
I have never tapped the brakes yet. OTOH I did land with the brakes
locked one time. Interesting experience.


At the rate it takes the Cessna single mains to retract, it's probably
stopped :-)

In the Deb it takes 10 to 12 seconds. POH says not to retract until a
safe altitude has been reached.


I'm not sure how tapping the brakes dislodges any snow. There's very little
shoe travel.

If they've been used the disks are warm to hot. tapping the brakes
could cause water to collect.


Correct, if you've got disks there's not much clearance there to begin
with. For other forms of brakes, it's not even going to do anything.

Of course all this stuff neglects the nose gear.

It doesn't have any brakes to freeze either.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

On Tue, 12 Oct 2004 10:00:16 -0400, Ron Natalie
wrote:

Teacherjh wrote:


I was taught to tap the brakes to stop the wheels from spinning before tucking
them away. (spinning tires bulge out a bit, or so I was told) I confess I've
never actually looked down (sometimes I fly a cutlass) to see how long it takes
them to stop on their own.


To me that sounds like a good way to have the brakes freeze.
I have never tapped the brakes yet. OTOH I did land with the brakes
locked one time. Interesting experience.


At the rate it takes the Cessna single mains to retract, it's probably
stopped :-)

In the Deb it takes 10 to 12 seconds. POH says not to retract until a
safe altitude has been reached.


I'm not sure how tapping the brakes dislodges any snow. There's very little
shoe travel.

If they've been used the disks are warm to hot. tapping the brakes
could cause water to collect.


Correct, if you've got disks there's not much clearance there to begin
with. For other forms of brakes, it's not even going to do anything.

Of course all this stuff neglects the nose gear.

It doesn't have any brakes to freeze either.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Rick Durden wrote:
Paul,

Tapping the brakes prior to retraction is one of aviation's old wives
tales that just hangs in there. The gear wells are large enough to
hold the tires even if they have some bulge from spinning (which isn't
much anyway on our slow little bugsmashers). There are some
transports in which the manual calls for tapping the brakes and some
in which it specifically says not to as the sudden stop on large tires
and wheels can cause the tire to slide on the rim.

The POH on my Trinidad (1986 TB21) calls for applying the brakes before
retracting the gear. Is there really no reason for this?

--
David Rind

Rick Durden wrote:
Paul,

Tapping the brakes prior to retraction is one of aviation's old wives
tales that just hangs in there. The gear wells are large enough to
hold the tires even if they have some bulge from spinning (which isn't
much anyway on our slow little bugsmashers). There are some
transports in which the manual calls for tapping the brakes and some
in which it specifically says not to as the sudden stop on large tires
and wheels can cause the tire to slide on the rim.

The POH on my Trinidad (1986 TB21) calls for applying the brakes before
retracting the gear. Is there really no reason for this?

--
David Rind

David,

Tapping the brakes was apparently started on larger airplanes because
on some there was a concern about the rotating tires in the wheel
wells; then the habit pattern passed on to little airplanes, despite
it not being necessary. Next time you can, observe a gear swing on
the airplane in the shop and see that the tire clears the sides of the
wells nicely. Even if there is some question of clearance on a little
airplane, the only thing that happens is that the tire rubs on the
well and comes to a stop. It isn't going to jam in there because it
was rotating and the tire was bulged out a little bit.

There is also a tendency for the folks who write POHs to put in a few
things because "we've always done it that way" rather than to spend
the time and money to check to see if it's needed. That being said,
if the manufacturer calls for a procedure, I would suggest following
it unless I've got good evidence it is counter productive, so on your
airplane, tap the brakes. In winter I don't touch the brakes at all
on a retractable gear airplane because I want the inertia from the
spinning tire to toss all of the moisture possible and second, if I
touch the brakes I heat up the brake shoe and disc, which will melt
any snow on it, but having stopped the rotation, I don't get rid of
the water. Then, because it's cold, the water freezes and I have a
frozen brake that leads to sliding one or both tires on landing,
something that has a certain level of discomfort.

All the best,
Rick

David Rind wrote in message ...
Rick Durden wrote:
Paul,

Tapping the brakes prior to retraction is one of aviation's old wives
tales that just hangs in there. The gear wells are large enough to
hold the tires even if they have some bulge from spinning (which isn't
much anyway on our slow little bugsmashers). There are some
transports in which the manual calls for tapping the brakes and some
in which it specifically says not to as the sudden stop on large tires
and wheels can cause the tire to slide on the rim.

The POH on my Trinidad (1986 TB21) calls for applying the brakes before
retracting the gear. Is there really no reason for this?

Ron Natalie wrote in message om...
Robert M. Gary wrote:


There are two things here. Tapping the brakes is something started in
WWII because a B-17 would tip over when the gear come up if the wheels
were spinning (imagine the gyro action happening on those big wheels).

Myth.

First, the wheels are NOT that big compared to the weight of the aircraft.

Second, the B-17 wheels are retracted along their plane of rotation.
They swing forward nestling in the inboard engine nacells. If you
land one gear up, it will roll on the retracted wheels (with other parts
of the aircraft scraping, however).

The DE who did my private told me about a friend that went through
flight training with him in the B-17 and later the B-24(could have
been 25 though). He crashed after take off because of this and spent
the rest of his life with scaring on his face from the burns.

-Robert

In article ,
David Rind wrote:

Rick Durden wrote:
Paul,

Tapping the brakes prior to retraction is one of aviation's old wives
tales that just hangs in there. The gear wells are large enough to
hold the tires even if they have some bulge from spinning (which isn't
much anyway on our slow little bugsmashers). There are some
transports in which the manual calls for tapping the brakes and some
in which it specifically says not to as the sudden stop on large tires
and wheels can cause the tire to slide on the rim.

The POH on my Trinidad (1986 TB21) calls for applying the brakes before
retracting the gear. Is there really no reason for this?



IIRC, the Trinidad gear retracts inward. Stopping wheel rotation
eliminates inertial coupling between the wheels and the gear pinoins.
You really don't want to make the wheel change its plane of rotation.

Robert M. Gary wrote:

The DE who did my private told me about a friend that went through
flight training with him in the B-17 and later the B-24(could have
been 25 though). He crashed after take off because of this and spent
the rest of his life with scaring on his face from the burns.

The B-24 and B-25 gear folds such that there would be some precession
effect. The B-17 just can't have any. The gear swings forward and up
along the plane of rotation.

(Robert M. Gary) wrote

There are two things here. Tapping the brakes is something started
in WWII because a B-17 would tip over when the gear come up if the
wheels were spinning (imagine the gyro action happening on those
big wheels).
The DE who did my private told me about a friend that went through
flight training with him in the B-17 and later the B-24(could have
been 25 though). He crashed after take off because of this and spent
the rest of his life with scaring on his face from the burns.

First.... why would I want to believe anything that ANY Flight
Instructor or Designated Examiner has to say about anything?
I've worked with them for too long and know better.

Second... I can easily see how this story has become corrupted.
If the pilot DOES apply the brakes on a B-17 with spinning tires,
then there WILL be a pitching moment applied to the airframe.
On a barely flying B-17, this could be a problem.

But, you can be forgiven Robert. From many years of experience
in de-briefing new private pilots after their practical test, I
found that very few could recall accurately the problem areas that
they had encountered and in discussing these with the DE, I would
receive an entirely different story. :-)

BTW, most Boeing jetliners have automatic wheel stopping brakes
that are applied with reduced pressure during retraction. The nose
wheels were stopped by wooden rub strips in the nose wheelwell.
Pilots were cautioned to not apply the brakes due to the sudden
stoppage breaking the tire bead to wheel seal.

Bob Moore