Yaw String in a Spin

John Galloway wrote:
At 15:00 18 January 2005, Don Johnstone wrote:

I think that the test pilots concerned knew exactly
how they got there but it may not have helped them
much. I re-call seeing a very good video of a Jaguar
that had departed and was tumbling end over end with
fuel being forced out of the jet intakes. I think the
pilot took about 20000ft to find a point where he could
break into the sequence and return to controlled flight.
As a result the action to be taken if a Jaguar departs
is seize the handle between your legs and pull hard.


Well, Don, its a good enough way of passing one's last
few moments but I would try ejecting rather than....
and the next part of the line is just so obvious I
can't even bring myself to finish.....damn - done it
again.

Now how would the NTSB address *that* in the accident report.
Delicately, I'd hope.

Shawn

At 14:31 18 January 2005, Colin Lamb wrote:
'What is most important is 'situational awarness'.
A pilot must learn to
know where he is and how he got there.'

The last part of that statemenht may not always be
true. I have read
reports from test pilots who intentionally place the
aircraft in
out-of-control positions in order to determine a recovery
procedure. A
common response is that they ride the aircraft until
they are in a position
they recognize and as soon as that happens they can
recover. How they got
there was irrelevant.

Although few airplanes use yaw strings (the pilots
are still behind the
curve a bit), they are normally used on helicopters.
Although the pedals
are used to counteract the torque of the tail rotor,
we operate them the
same way - keep the yarn centered.

Colin N12HS

Wha-a-t?

How can you use a yaw string in a helicopter? Doesn't
the rotor wash it around? Educate me.

(I had one helicopter ride in an H-13 in 1954; didn't
see no stinkin' yaw string.)

"How can you use a yaw string in a helicopter? Doesn't
the rotor wash it around? Educate me.

(I had one helicopter ride in an H-13 in 1954; didn't
see no stinkin' yaw string.)"

Helicopter pilots have learned a lot since 1954. I fly helicopters (just
Schweizers). Perhaps the production crew kept putting them on from
sailplane days, but they work just like any other yaw string. And, they are
brightly colored yarn, too. Only one of the helicopters I have flown has a
turn and bank indicator - and all have the yarn.

When you are hovering, the yarn is meaningless - but you are not going
anywhere, either. As soon as you move to forward flight, the relative wind
goes from the front of the helicopter to the back, just like any other
aircraft.

At best glide ratio, I get just over 3:1, but with a headwind the glide
angle approaches that of an elevator.

Colin N12HS



---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/04