Crosswind landing control..

Jim Macklin wrote:
Boeing airliners are designed to have the nose wheel firmly
on the ground, some even have a brake. But no airplane is
designed to have the nose forced/slammed down except maybe a
carrier based fighter.

But back to the GA aircraft and effective nose wheel
steering... steering works with the weight on the main
landing gear and the nose wheel applies force to move the
nose. If you apply forward elevator you'll be loading the
nose wheel and shifting the pivot point [fulcrum] to the
nose wheel, this will cause the airplane to weathervane even
more and result in loss of directional control.



wrote in message
oups.com...

Matt Whiting wrote:
Dan wrote:
All,

When touching down in a crosswind, after the mains and
the nosewheel
have all touched down firmly and are rolling, would it
be proper
procedure to apply slight forward pressure to get better
steering from
the nosewheel? Often, noseweel steering seems
ineffective, and this
seems to have helped my control on rollout.

Any cautions? I have heard about "wheelbarrowing" but
is that more of
a takeoff issue than landing issue? Under what
circumstances would
"wheelbarrowing" occur?

--Dan


I was taught to basically use neutral elevator during the
roll-out. You
really shouldn't need to add forward pressure to get solid
steering.
Wheelbarrowing is a possibility if you apply aggresive
nose down
elevator right after landing when you speed is high, but
as you slow
down the ability to do this obviously decreases.

What are your symptoms of ineffective nosewheel steering?
Are you not
able to hold the airplane on the centerline? Are you
rolling in aileron
into the wind as you slow down such that you have full
aileron into the
crosswind as you get to taxi speed?

I happened to bump into this:-
http://www.aaib.dft.gov.uk/cms_resou...pdf_507740.pdf

It discusses forward pressure immideately after landing
says:-

Boeing 757-2T7, G-MONC
Nature of Damage: Structural damage to forward
fuselage in area of nose landing gear
....
Having developed an incorrect landing technique, it is
possible
that it was simply a matter of time
before the timing in the application of full nose-down
elevator caused an incident

I thought that there was a resonance with this discussion.

If a supervised, recurrently-trained, co-piloted, airline Captain
can go astray like this what chance is there for a GA pilot
on his own? Phew!

In the full text I think that it suggests that he may have
"performed" differently in his check rides than in his day
to day flying.

Nothing malicious (intended by me or him - think it was a man),
just somehow gone down an incorrect path.

I agree 100% that the elevator can generate an upward force and pushing the
stick forward in a tricycle plane to put weight on the nose is NOT a good
idea in general. I would think it would be very easy to over do it.

Danny Dot

The bigger problem in wheelbarrowing is the too-fast touchdown.
The wing, if you remember your groundschooling, generates more lift at
a lower angle of attack at a higher airspeed, and a fast landing is at
a flatter attitude. Since the nosewheel usually keeps the airplane
slightly nose-high on the ground compared to flight attitude, the
nosewheel will land first, and without the control the mains offer, the
airplane becomes a really nasty taildragger. Forcing the elevator down
only make it worse, and having flaps deployed lowers the nose even
further for a given airspeed. Years ago one of our students ran a 150
off the runway into the snow and overturned it, just because he
wouldn't slow the airplane to the proper approach speed and get in on
the right glidepath. Trying to fix a bad approach by diving at the
runway and then forcing the airplane on long before it should land is a
sure way to get hurt and bust your airplane, sooner or later.
This thread was about crosswind landings. The biggest and most
common mistake I see there is the belief that the flight is over after
the wheels are on the ground. He will neutralize the controls,
including the ailerons, and in the rollout the wind could pick up the
upwind wing and flip the airplane over. More and more aileron should be
applied after touchdown until it's all used up, and then held there
until the rollout is complete. Even in taxing in a stronger wind the
controls should be used to prevent upset.

Dan

Capt. Geoffrey Thorpe wrote:
"Dan" wrote in message
ps.com...
My impression that the elevator applied varying levels of downward
force to balance the plane about the center of lift. I am not aware
that the elevator could even produce _upward_ force on the tail.


If the elevator couldn't generate an _upward_ force, then you couldn't pick
up the tail on an taildragger, right? Let me assure you, you can pick up the
tail on a taildragger.

Sure you can, but much of that lift is a pitch couple generated by
the prop's thrust line being so far above the locked mains while
standing still, and lifting of the tail while moving is largely due to
the wing's CP being well behind the mains. If you can see the elevator
in cruise flight you'll see that it is down some, to counteract the
downforce of the stabilizer.
The elevator's lifing force in some airplanes might not be
enough to maintain nose-up in inverted flight; aerobatic airplanes have
more elevator travel and the CP and CG may be closer together to reduce
the inherent stability.

On 29 Dec 2006 05:28:48 -0800, "mad8" wrote:

that was a very interesting read


wrote:
I happened to bump into this:-
http://www.aaib.dft.gov.uk/cms_resou...pdf_507740.pdf

Even with aircraft designed for using the nose gear with braking, this
shows it's not a good idea to force the nose down. :-))
That and you sure can tell the report writer was using English
English instead of American English:-))

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