[NSRCA-discussion] Weather Vane or Crab

[george w. kennie]

Marty,
The problem I have with the "unconcious control input" theory is, ....there 
are hundreds of "Sport" flyers in all 3 of the local clubs that I belong to 
that subscribe to the idea that the rudder is meant to be used only when the 
plane is on the ground. One of the guys at my #1 field places his thumb 
against the base of the throttle stick as soon as the plane is safely in the 
air and the throttle and rudder control are never touched "til the wheels 
are back on the ground. Despite the fact that these guys never even breathe 
on the rudder, their planes exhibit the same fuselage rotation into a cross 
wind on vertical uplines that my planes do.
G.



----- Original Message ----- 
From: <moleski at canisius.edu>
To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
Sent: Sunday, October 14, 2007 4:40 AM
Subject: Re: [NSRCA-discussion] Weather Vane or Crab


> Winston E Batchelor wrote:
>
>> Thanks George
>
>> I really didn't want to argue with Doug.
>
>> ... I was in no way experienced enough to make a correction. IN fact it 
>> alomost
>> blew me onto the shoulder of the road ...
>
> I suspect that you experience on the bike and other people's experiences
> with weathervaning of pattern planes are examples of "tacit knowledge,"
> an idea developed by Michael Polanyi.
>
> The vast majority of people do not know what rules they are following
> when they ride a bike.  They acquire the skill tacitly (silently) and
> don't even realize what they themselves are doing to maintain their
> balance.  The corrections are quick and intuitive, beneath the level
> of consciousness.
>
> The trick that we use to maintain our balance is to steer into
> a fall.  If we're falling to the right, we swing the bars to the
> right.  That causes the frame to straighten up.  It may go past
> neutral and start falling to the left.  If so, we swing the
> bars to the left.
>
> This is very evident at super slow speeds.
>
> To disrupt our balance so that we can make a turn, the
> first thing we do is to turn AWAY from the way we want to
> go.  To initiate a right-hand turn, we swing the bars to the
> left, which causes us to start falling to the right; then
> we swing the bars to the right to stop the fall, but not
> so far to the right that we come upright--we lean into
> the turn.  When it's time to come out of the turn,
> we pull the handle bars more to the right, which
> throws us toward the left and causes the frame to
> come upright.
>
> Video of robot motorbike in which the designer briefly
> explains the principle:
>
> http://www.youtube.com/watch?v=XOgkNh_IPjU&mode=related&search=
>
> In the case of perceived "automatic compensation for the
> wind," I suggest that people are setting the groundtrack
> for the plane without even knowing that they are doing it.
> When they get the plane tracking straight across the ground,
> it will be properly yawed into the crosswind.  It is
> the pilot who achieves the balance between the force of
> the wind trying to carry the plane off the line and the
> force needed to compensate for that which comes from
> yawing the plane into the wind.  It happens so fast and
> is so natural that people think the plane is doing it--or,
> in the case of the wind unsettling your balance, you thought
> that the motorcycle itself is doing the balancing act.
>
> Marty
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