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 | | From: | Jim | | Subject: | Wings-level "skid" or "slip"? | | Date: | Tue, 11 Jan 2005 11:34:05 -0800 |
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As the weather has kept me on the ground for a couple of weeks, I have
indulged my curiosity with some wonderings about skids and slips.
What brought this all to mind was some fairly botched forward slips I
have been practicing in gliders. The very long wings allow only slow
rolls, but the rudder can produce quite rapid yaw. Consequently, when
I fail to lead with adequate aileron I sometimes end up with a rather
wings-level, yawed orientation. I have not yet had the nerve to press
on to the point of a stall when in this state, so it remains a thought
puzzle.
As soon as I can get in the air again I'll see if a little
experimentation can clarify some of my thinking.
I'm afraid the following recounting of my wonderings is a bit of a
tangle, to say the least, but I would be very grateful for any
guidance.
Here is the question that I have been turning over in my mind:
Can a wings-level, rudder-induced, yawed but stable (the yawing
motion has stopped) orientation be called a "skid" or a "slip", or do
"skid" and "slip" only apply to a banked orientation?
In wings-level flight it doesn't seem possible to apply "too little
rudder", as in a slip, for the amount of aileron being applied, just
because NO aileron is being applied. Does this mean a wings-level
slip is not possible, or not defined?
On the other hand, because no aileron is being applied in wings-level
flight it would appear that ANY rudder application would be "too
much". Does this mean that a wings-level, stable, yawed orientation
is by definition a "skid"?
But a stalled, skidded turn is said to result in a spin "out the
bottom", in the direction of the over-applied rudder. Does this
suggest that an aircraft that is stalled while in a stable,
wings-level, yawed orientation will be likely to spin in the direction
of the applied rudder?
In a wings-level, stable yaw, once the aircraft is established in the
new position and the yawing moments have stopped, I can see that wing
dihedral may result in the leading wing being at a higher AOA than the
trailing wing. If this is the case, then it would seem the leading
wing, opposite to the applied rudder, would stall first - unless you
are applying into-the-skid aileron to counter the dihedral-induced
opposite roll, in which case, it may be the trailing wing that is at
the higher AOA, and this may well vary with the relative forces
produced by the wing dihedral on one hand and the weathercock action
of the vertical stabilizer on the other hand.
Can any kind soul help me sort this out?
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