|
The
Prez Sez
Hi Folks,
Welcome to the August
2003 edition of our newsletter. I can't believe that it is August already
- soon it will be time for the annual Christmas party. There are two issues
that I'd like to talk to you about, and get your input on the one. At last
month's club meeting, one member requested that he be allowed to conduct
a survey of the club members to determine what their desires were for Bollin
Field. To date, the survey has not appeared. You will recall that we ran
a survey over the winter months, and your direction to me was to get the
field paved, get water and electricity, and secure the Field. Would you
all take just a moment and drop me an email to let me know if that direction
has changed?
Thanks!
Next, with no feedback
required, several of our newer pilots have asked "What is the difference
between high wing and low wing aircraft". My old friend, Clay Ramskill
from Dallas, Texas is a skilled teacher and avid writer, and has written
the following on this subject:
High Wings Versus
Low Wings by Clay Ramskill
We finally master our
high wing trainer, or trash it, whichever comes first. Maybe then we build
a shoulder wing plane. Only after we are somewhat competent at flying do
we try flying a low wing plane, and then with white knuckles and shaky
knees. WHY? Just what is it about low wingers that make them "tougher"
to fly? Are they faster? No! All other things being equal, there's virtually
no difference in drag, or therefore top speed. The illusion comes from
designers' choice-they tend to put faster airfoil sections and lower aspect
ratios on low wing planes, making them speedier. Low wing planes do have
several characteristics, compared to high wingers that make them more suitable
for higher performance aircraft.
1."Nicer" (and quicker)
roll response. This comes from the relative placement of the Center of
Gravity, being closer to the natural roll center of the wing. Assuming
at least a little dihedral, the CG will be at or only slightly above the
roll center of a low wing, but well below that of a high wing. In a roll,
the wing (providing the "power") wants to roll about its own roll center.
The rest of the plane (the "resistance") wants to roll about the CG. The
wider the distance between roll center and CG, the funnier-looking is the
roll (i.e., "non-axial").
2. The low wing lends
itself to a less stable stabilizer position, leading to more pitch maneuverability.
With a high wing, it's simple, and natural, to have the stabilizer well
below the wing. When the nose is pulled up, the stab drops down well below
the wing's downwash, and becomes increasingly resistant to further AOA
(angle of attack) increases. This is great for stability, and makes stalls
less likely. The opposite is true for the low winger. With a pull-up, the
higher stab drops into the wing's downwash, making further AOA increases
easier, and the plane more maneuverable.
3. The low wing reacts
more neutrally to power changes. Our old high wing trainer, with the thrust
line very low, will respond by pitching nose up when power is added, nose
down if power is reduced. This contributes to stability, with the nose
going the way we want it to on a trainer. On the other hand, the low winger
will be more neutrally stable, without much pitch reaction to power changes.
The low winger will also be more wind "resistant"on the ground, a function
of wing height above the wheels. The high winger will naturally be more
"tipsy," reacting to wind while taxiing and during takeoff and landing.
We must all understand that we're only talking of tendencies here. There
are many other variables that have an impact on the characteristics involved-the
designer can juggle these around to get the desired handling. But wing
placement is definitely one of the biggies when it comes to establishing
how a plane is going to handle.
Till next month, Bill
Club Meeting
The next meeting of
the MMRCC is scheduled for August 7, 2003 at 7:00 P.M. The meeting will
be held at the Northrop Grumman facility (Same place, only the name changed
from TRW. Highway 90 Bypass). Personnel are required to sign-in and sign
out for security purposes. |