----- Original Message -----
From: "Fergus Kyle" <VE3LVO@rac.ca>
Subject: Europa-List: monowheel positon of stab and aileron
>
> >Subject: Europa-List: Monowheel position of elevator and aileron?
> >Sorry to bother you with this question, figured would get an easy answer
> from the >group.
> > NOT!
> > Curious
> > When taxing a monowheel with a 20 knot quartering tailwind, lets say
from
> the left, do
> >you keep the elevator full forward and the stick full deflected to the
> right?
> There IS a difference between an elevator and a stabilator. The
> first changes the shape of the control surface, such that
a
> down elevator curves the elevator/stabilizer control making it more
> sensitive to unwanted wind vagueries. The stabilator does not
> change shape so is not as sensitive (say to tipping up the tail from a
> tailwind). Judging the severity of the effect is a Command
decision
> and comes mostly from experience
>
> >Since the Europa has outriggers, for all I know dragging the downwind
> outrigger does >more good in keeping things straight than trying to keep
the
> upwind wing down?
> Because of outriggers, the problem of preventing wing-up events
> tends to be less critical. Nevertheless it is good practice to select
up
> aileron into wind o spoil any potential lifting tendency. All of this
> of course depends on the strength of the gust/wind. I would
believe
> any sidewind meeting a lifting surface would tend to reduce
> directional control, even slightly.
>
> >As far as the elevator, for all i know perhaps the huge prop spinning
puts
> flow from >front to back instead of back to front?
> I dont believe (with a tailwind) you will want to add to its
effect
> by increasing speed/power with the prop. The only time to
> blast with power is to correct a sudden swing - and then only for an
> instant. This is a neglected practice, but a vital one in a Boeing
> Stearman. Otherwise, throttle back.
>
> >I honest don't know, but my guess is full forward and full to the right.
> I wont do that. You are reducing the one thing giving directional
> control - the tailwheel
Besides, I dont think theres a hard and fast
> rule for any control position. If you sense a threatening tailwind,
> stick full back because the stab will be stalled and you may be adding
> weight to the tailwheel.
Ferg and all.
It all depends, - at what speed is the slipstream from an idling prop
travelling (in zero wind conditions)? I think we need to know this figure
as it will give us a cue on how to put the stick should we pick up a
tailwind. A strong wind from behind can easily overcome this prop wash - and
I believe that sitting with the stick in your lap under such conditions can
give you a surprise. It will do you no good for tailwheel steering as the
pressure on it will be less than with zero wind. The wind will simply push
on the upward orientated stabilator. (Or elevator).
Another cue would be to simply hold the stick in the direction "it's being
blown". (Pitch-wise). And if that's forward it would indicate that the
tailwind has overcome the propwash and that the wind from behind will press
on the downsloping stab as seen from the rear - giving increased pressure on
the tailwheel. We do this on the DC-3, and in the old days, on the "ground
looping bastard" Curtiss C-46, this was even more so the bible. Taxying
these aircraft are a challenge and often a two-man job. The name of the game
was (and is) to proceed with utmost caution (read taxying at walking pace)
and "fly" the aircraft while ground maneuvering - meaning stick always into
wind to spoil lift on upwind wing and to let downwind aileron act as
airbrake. The Europa mono may be even more challenging without
differentional braking capabilities. Some maximum wind figures would
therefore be wise to establish. !
Hans, kit 334, in Norway.
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