Winter flying with retractable gear?

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.

Check the manual for your airplane for winter operations. Some
suggest to delay gear retraction for a bit to help blow off
snow/slush/water. The inertia from the spinning tire usually tosses
off most of the contamination (allowing it to freeze to the underside
of the wing g) and waiting a bit to suck the gear up allows the
airflow to take it off the brake discs and other, stationary, portions
of the gear. Having the gear freeze up is pretty rare. More common
will be that you'll taxi through some snow that gets on the brakes, it
melts on the discs and then freezes one or both of the brakes after
takeoff. Just land on centerline to give yourself room for a swerve
as it takes a moment or two of sliding tire(s) before the brake
unfreezes and you have rolling control. Naturally, it occurs when you
make one of those lucky, smooth touchdowns and you hear the squeal of
a tire sliding, then the pop as the ice lets go and things go back to
normal. Not usually a big deal, but folks have gone into the
snowbanks adjacent to the runway due to not reacting quickly enough.

All the best,
Rick

(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?

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?

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.

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