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).

Robert,

Don't know where you got the idea a B-17 would "tip over" should the
gear be retracted with the tires rotating. The gear retracts in its
plane of rotation. As a result of your post, I got in touch with one
of the folks who gives checkrides in B-17s (and all other WWII
multi-engine aircraft) and was advised that the subject is discussed
from time to time, but is an old wives tale. Boeing does not call for
the brakes to be used after takeoff on their WWII bombers. I was told
that the CAF procedure is not to touch the brakes on the B-17 to stop
the wheels from rotating. The matter tends to be airplane specific,
on the B-29 they recently started using the brakes because they are
concerned about clearances with the gear doors/wells, but he said that
was the only one. If you look at the gear for many of the WWII and
later large aircraft, there are red marks on the tires that line up
with red marks on the wheels so the crew can see if the tire has slide
on the wheel.

All the best,
Rick

(Robert M. Gary) wrote in message . com...
(Paul Tomblin) wrote in message ...
This will be my first winter flying the club's Lance. One instructor told
me that you want to tap the brakes before retracting the gear to dislodge
any slush or snow so that it doesn't freeze in the wheel well, and I read
somebody else saying that you should hold off retracting the gear after
take-off for a little while to blow the slush and snow off. Should I do
one or the other or both?

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).
I believe most large aircraft today automatically apply brake pressure
when the hydro lifts the gear.
In the Mooney world we always read about Mooney pilots taking off,
getting slush in the gear and then freezing at altitude. I don't know
how tapping the brakes would change that though.

-Robert, CFI and Mooney owner

"Rick Durden" wrote in message
...
If you look at the gear for many of the WWII and
later large aircraft, there are red marks on the tires that line up
with red marks on the wheels so the crew can see if the tire has slide
on the wheel.

We have that on all our planes here in the UK.

It's one of the things to check on the pre-flight, that the tyre hasn't
rotated on the rim, possibly damaging the valve.

Paul

On 12 Oct 2004 08:26:18 -0700, (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).
I believe most large aircraft today automatically apply brake pressure
when the hydro lifts the gear.
In the Mooney world we always read about Mooney pilots taking off,
getting slush in the gear and then freezing at altitude. I don't know
how tapping the brakes would change that though.

-Robert, CFI and Mooney owner

Don't see how this can be possible. You're saying that if the brakes
aren't tapped to stop the rotation of the tires before they arrive at
their wheel wells, this four engine bomber which may be carrying a
load of bombs simply tips over? At 120mph? What makes this happen?
The tires don't hit anything when they reach the wheel wells, they
continue rotate. Even with the wheels up and locked in position, the
tires can still turn. Paul Mantz utilized this feature to steer the
B-17 he had been tasked with landing gear up for the movie "12 O'Clock
High" once he'd set it down. He was supposed to skid through a tent
that had been conveniantly left out beside the runway for this
purpose. He found that once he was down and skidding, he could use
left and right brake to make sure he plowed through the tent. This is
in his memoires. It was a Hollywood moment of course, no tents were
ever pitched out beside any active runway.

It would have to take one hell of a lot of inertia for something to
flip a B-17 up on it's nose after having lifted off and climbing out
under takeoff power.

In another related instance, I read of a B-17 pilot who was senior at
the air base. It was his job to test various bombers that had been
repaired. He flew one which he said lifted off at the correct speed,
but then settled down onto the runway again, momentarily, and then
lifted off again. He tested this out several times and it did it
every time. So he merely made note of it and recommended that for
this particular airplane the brakes NOT be tapped, as was normal
practice during takeoff, but to leave them revolving so that when the
bomber touched down again on the runway, there would be no screeching
of tires and possible blow out.

Next mission he was assigned that bomber. He was in the left seat
with a relatively new pilot in the right seat. He remarked that the
guy was impulsive and despite being told NOT to tap the brakes after
liftoff, to wait until the bomber had settled back down and then
lifted off again, the guy tapped them anyway after the initial liftoff
and sure enough, the airplane promptly settled back down on the runway
with juddering and screeching from the now stopped tires as they were
spun up again. Luckily, neither of the tires blew out, but the pilot
had to write up the incident so that the ground crew would replace the
tires as they were now flat spotted.

Corky Scott

(Paul Tomblin) wrote in message ...
This will be my first winter flying the club's Lance. One instructor told
me that you want to tap the brakes before retracting the gear to dislodge
any slush or snow so that it doesn't freeze in the wheel well, and I read
somebody else saying that you should hold off retracting the gear after
take-off for a little while to blow the slush and snow off. Should I do
one or the other or both?

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).
I believe most large aircraft today automatically apply brake pressure
when the hydro lifts the gear.
In the Mooney world we always read about Mooney pilots taking off,
getting slush in the gear and then freezing at altitude. I don't know
how tapping the brakes would change that though.

-Robert, CFI and Mooney owner