Curious incident :)

Pete

The F-101B had enough engine power that if you held the brakes and ran
up and plugged the burners in it rotated the tires on the rim(s) and
blew them.You could see smoke as they skidded down the R/W.


Technique was to run up to around 80% and check gauges and release
brakes and advance throttle(s) to 100% and plug the burners in.

TOR was less than 1000 feet on a standard day.

Big John
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On Tue, 20 Dec 2005 11:03:22 -0800, "Peter Duniho"
wrote:

"Ramapriya" wrote in message
roups.com...
Paul Tomblin wrote:

Since when does smoke come of the tires of a plane starting its takeoff
roll? I can't think of any way that could happen.

My thoughts exactly.

Don't know about you but I've seen puffs come off aircraft tires, at
the start of the takeoff roll, often enough; it probably happens when
pilots advance the throttle a bit before releasing the brakes.

I've never seen that, nor even heard of it. The proposed explanation you
suggest certainly wouldn't do it. Smoke comes off the tires during
touchdown because of the speed difference between the tire and the pavement,
until the tire "catches up".

During takeoff, even if the brakes are held, and even if the tires slide a
bit (which is very unlikely...usually the locked wheels can hold the
airplane still), they wouldn't smoke. They'd just rub a bunch of rubber
onto the pavement.

If you saw smoke during the takeoff roll, it came from somewhere other than
the tires.

Pete

Peter Duniho wrote:

Don't know about you but I've seen puffs come off aircraft tires, at
the start of the takeoff roll, often enough; it probably happens when
pilots advance the throttle a bit before releasing the brakes.

I've never seen that, nor even heard of it. The proposed explanation you
suggest certainly wouldn't do it. Smoke comes off the tires during
touchdown because of the speed difference between the tire and the pavement,
until the tire "catches up".

During takeoff, even if the brakes are held, and even if the tires slide a
bit (which is very unlikely...usually the locked wheels can hold the
airplane still), they wouldn't smoke. They'd just rub a bunch of rubber
onto the pavement.

If you saw smoke during the takeoff roll, it came from somewhere other than
the tires.

Pete

Could be a terminology error here, Pete

As I stated before, I've often seen puffs from behind tires. In fact,
when seeing aircraft readying for a takeoff from behind a glass pane
between the 5 o'clock and 7 o'clock positions, I look for tire puffs to
know that the craft has begun its roll. It could well be a spray of
water or sand off the tarmac, but I have seen it often, no doubt about
it.

Ramapriya

Morgans wrote:

I also can not imagine what could cause what you said. You said smoke left
the tires of the 747? What would cause tires of a stopped aircraft (just
beginning to roll) to smoke?

Giving it full power before fully releasing the brakes?

George Patterson
Coffee is only a way of stealing time that should by rights belong to
your slightly older self.

"Big John" wrote in message
...
The F-101B had enough engine power that if you held the brakes and ran
up and plugged the burners in it rotated the tires on the rim(s) and
blew them.You could see smoke as they skidded down the R/W.

Hardly relevant to the question of what happens at the *very start* of a
takeoff roll of a transport category airplane. Even in the case of the much
higher power-to-weight ratio of the F-101B (or other fighters, for that
matter), the smoke doesn't occur immediately upon power-up.

Pete

"Ramapriya" wrote in message
ups.com...
Could be a terminology error here, Pete

Well, if you are using the word "smoke" to describe something that is not
actually smoke, I can see how that would be a problem.

Ramapriya wrote:

...when seeing aircraft readying for a takeoff from behind a glass pane
between the 5 o'clock and 7 o'clock positions, I look for tire puffs to
know that the craft has begun its roll. It could well be a spray of
water or sand off the tarmac, but I have seen it often, no doubt about
it.

I don't doubt you've seen something. From five- or seven o'clock it
could be dust kicked up by wing-mounted jet intakes that might appear to
come from the main gear. I've watched a lot of large and heavy jet
departures from the number one position and I don't remember seeing
anything that could be interpreted as smoke from the tires under those
circumstances.

Curious, indeed.


Jack

"George Patterson" wrote in message
news:1P4qf.17527$l25.6310@trnddc03...
Morgans wrote:

I also can not imagine what could cause what you said. You said smoke
left
the tires of the 747? What would cause tires of a stopped aircraft
(just
beginning to roll) to smoke?

Giving it full power before fully releasing the brakes?

Not that it *couldn't* happen, but I think that it is unlikely.

Generally, smoke only happens when there is a considerable speed difference
between the rubber and the road. If you drag a tire from a standing start,
you make a little noise, deposit some rubber (perhaps considerable), but you
don't generate enough heat to make smoke. These are my observations, but
YMMV.

Anyway, I would like to see smoke from extended brake holding while spooling
up.
I would bet that it would have to drag 10 feet or more, to build up enough
heat. It seems more likely, to me, that a little smoke came from the engine
going to full power.

A little (nah, really big) story along these lines, a long time ago on a
747.

I was in "The Ohio State University Marching Band" (TBDBITL) when we went to
the 1980 Rose Bowl. With all of the brass instruments, drums, and personal
luggage and fuel for that long trip, I have no doubt that we were at, or
very near max gross takeoff weight. I don't know how long Port Columbus
(Rickenbacker Field) was at the time, but with the weight and size of the
aircraft, and the length of the runway, it must have been close to minimum
lengths.

The pilot went to the departure end, and went down as far as he could before
turning around and lining up on the runway centerline. After a brief hold,
he spooled up the engines and held brakes for what seemed like *much* longer
than usual. I am almost sure that there were some tires sliding. The
brakes where finally released, but there was not the usual "kick in the
back" acceleration, but we did roll on down the runway, getting airborne at
what seemed like the last moment. Trip was completed successfully, but that
takeoff was exciting, for sure.

It was during the return trip that we dropped suddenly, and kicked sideways
at the same time, just as flight attendants were clearing supper trays. I
ended up with 5 or so plates held directly over my head, without a morsel
spilling on my head. "Good catch, miss, thank you," says I !!! This was
after sleeping on the floor of LAX for 5 or 6 hours, after our chartered
plane was fogged in at San Francisco. Oh, we lost the game also, and had
been up since 4:30 AM, to march in the Rose Bowl Parade. What a day!

Sorry for my ramblings. It was a good time.
--
Jim in NC

Jack wrote:

I don't doubt you've seen something. From five- or seven o'clock it
could be dust kicked up by wing-mounted jet intakes that might appear to
come from the main gear. I've watched a lot of large and heavy jet
departures from the number one position and I don't remember seeing
anything that could be interpreted as smoke from the tires under those
circumstances.

Curious, indeed.

Jack


What began as a question to ascertain the frequency of aircraft landing
from above another has turned (due to my poor verbiage, possibly) to
how smoke emerged from the 747's wheels on takeoff

Is it common to see planes commencing their takeoff roll before a
just-landed aircraft has fully turned off into the exit? That clearly
happened in the incident I wrote about too...

Ramapriya

Ramapriya wrote:

Is it common to see planes commencing their takeoff roll before a
just-landed aircraft has fully turned off into the exit?

It happens --- more in some environments than others. Domestic US
operations are pretty standardized now, but there are a lot of
operations in many other parts of the world that would not be acceptable
to the FAA.


Jack

"Ramapriya" wrote in message
ups.com...
Is it common to see planes commencing their takeoff roll before a
just-landed aircraft has fully turned off into the exit? That clearly
happened in the incident I wrote about too...

Define "commencing". The way I read your initial post, the departing
airplane was not on the runway yet. So, the first movement would be simply
to get onto the runway. That would be perfectly acceptable. If the runway
is cleared by the time the departing aircraft gets lined up, they may
receive a takeoff clearance without any interruption, making it appear as
though they were cleared for takeoff earlier, even when they weren't.

Frankly, I'd think the whole "smoke from the tires" thing would have been a
suitable caution to you to not assume too much about what you think you are
seeing. So much goes on "behind the scenes" in the way of coordination, and
it's hard to know from outside the airplane exactly at what points the
various steps of the sequence of taking off are actually occuring.

Pete