High or low wing?

"Ray" wrote in message
...

Okay, so all kidding aside, what are the issues between high and low
wings? I know that in terms of flying, there are very few differences
between your average Cessna and Piper, but for higher performance
aircraft, what are the aerodynamic/design tradeoffs?

For example:

Why are most of the more expensive private aircraft (cirrus,
pilatus, pretty much all multi engine and jet) low wings?


In high-performance aircraft a low wing makes a convenient place to stow the
landing gear and also makes engine inspection easier. But there are
high-performance aircraft with high wings; Mitsubishi MU-2, Extra 400,
Cessna 210, etc.



Why do all fighters since the biplane era have low wings?


Ever heard of the McDonnell F-15?



Why do most military transports (C-130, C-17, C-5) have high wings,


It allows the fuselage to be closer to the ground for easier
loading/unloading.



but all airliners have low wings?


BAe 146, ATR 72, Dornier 328, etc.



Why are a lot of cold weather/high altitude planes high wing?


Aerodynamic superiority.

Why do all fighters since the biplane era have low wings?


Ever heard of the McDonnell F-15?


Okay, when I said all I really meant to say most, or a lot. What I was
thinking about in particular were the WWII fighters. I can't think of any
propeller driven fighter with a high wing. Your comment about low wings
being easier for landing gear makes a lot of sense, many of those aircraft
stowed their gear in the wings, but I wonder if there were any other
reasons. The first jet fighters were also mostly low wing (f-80, f-86,
f-100, mig-15, mig-19, etc). Only the latest generation of fighters (f-15,
f-14, f-22, etc) are predominately high wing.



Why do most military transports (C-130, C-17, C-5) have high wings,


It allows the fuselage to be closer to the ground for easier
loading/unloading.


This makes sense. But going back to WWII again, why were the early
transport aircraft (like the C-47) low wing?



but all airliners have low wings?


BAe 146, ATR 72, Dornier 328, etc.


Again I meant most instead of all, and I was referring to the larger
airliners (200+ seats). Basically, if all other things were equal, why
wouldn't they have made the 747 high winged, since some 747s are used for
cargo?



Why are a lot of cold weather/high altitude planes high wing?


Aerodynamic superiority.


To clarify here, by high altitude I meant planes that are designed to take
off and land at high altitudes - the pilatus pc-6 for example.

"Ray" wrote in message
...

Okay, when I said all I really meant to say most, or a lot. What I was
thinking about in particular were the WWII fighters. I can't think of any
propeller driven fighter with a high wing.


Morane-Saulnier L, Bristol M. 1C, Fokker D VIII, Wibault 72 C 1,
Loire-Gourdou-Leseurre LGL 32 C 1, Dewoitine D 27, Morane-Saulnier MS 225 C
1, Loire 46 C 1, Nakajima Army Type 91, Focke Wulf Fw. 56 A-1, PZL P.7, were
all propeller driven fighters with a high wings.



This makes sense. But going back to WWII again, why were the early
transport aircraft (like the C-47) low wing?


Cargo aircraft of that era were not built for the purpose but adapted from
civil airliners.



Again I meant most instead of all, and I was referring to the larger
airliners (200+ seats). Basically, if all other things were equal, why
wouldn't they have made the 747 high winged, since some 747s are
used for cargo?


Used for cargo but designed for people. A low wing tends to be preferred
for people carriers for several reasons. Using a low wing gives the
passengers a better view, a high wing would have them looking at the engines
and unserside of the wings. The lower portions of the fuselage aren't going
to be used for the passenger deck anyway so it's a good place to put the
wing carry through structure, and the wing-fuselage junction makes a good
place to put the landing gear. A high wing would require the bulbous
appendages you see on the C-17 to stow the gear or giving up baggage/cargo
space.

Ever heard of the McDonnell F-15?

Neither the F-15 nor the F-14 are "high wing" aircraft.

Most of the fuselage, and all of the cockpit, are above the wing. I suppose
you could call them "mid-wings," if you wanted to split hairs, but in my
opinion if you step out of the cockpit ON TO the wing, it's a "low wing"
aircraft.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

"Jay Honeck" wrote in message
news:KCpnc.11372$536.2196107@attbi_s03...

Neither the F-15 nor the F-14 are "high wing" aircraft.


Of course they are, don't be ridiculous.

"Jay Honeck" wrote in message
news:KCpnc.11372$536.2196107@attbi_s03...
Ever heard of the McDonnell F-15?

Neither the F-15 nor the F-14 are "high wing" aircraft.

Most of the fuselage, and all of the cockpit, are above the wing.

Almost none of the fuselage is above the wing.

Ray wrote:

Okay, so all kidding aside, what are the issues between high and low wings?
I know that in terms of flying, there are very few differences between your
average Cessna and Piper, but for higher performance aircraft, what are the
aerodynamic/design tradeoffs?

OK, if you want a serious answer rather than a punch line, here goes.

Typically, high-wing planes have struts bracking the wings, and those add
extra drag (some high wings, like the Cessna Cardinal, manage to avoid
struts) -- that drag can become very significant at higher speeds. On the
other hand, low-wing planes that want a lot of roll damping (such as
trainers) have to use a higher dihedral angle than high-wing planes, and
that also adds drag. If you want to build a high-performance,
highly-responsive plane (i.e. very little roll damping), a low wing is
probably the best choice, but I'm not an engineer or a scientist, so others
may step in to correct me.

High-wing planes are far better for bush work. The wings are less likely to
hit bushes, shrubs, fenceposts, and so on, and on floats, the high wings
will easily clear the dock. I'm happy to take my low-wing Piper Warrior
onto a well-maintained grass strip, but I won't land on a farmer's field
outside of an emergency. Of course, I wouldn't land a high-wing nosewheel
plane like a 172 or 182 on a farmer's field either -- high-wing or low-wing,
with a nosewheel you're only one gopher hole away from a prop strike and
engine teardown. Serious bush types around here (central Canada) normally
fly high-wing *tailwheel* planes like the Super Cub, C-180, C-182, DHC-2
(Beaver), etc. You can land and taxi those almost anywhere. High-wing
pilots also worry less about hitting a snowbank with a wingtip during the
winter -- that might be an advantage if you fly in snow country.

Low-wing planes are better for crosswind landings and taxiing, because the
wheels are considerably further apart than they can be on a high-wing
single. If you're flying mainly to paved airports or well-maintained grass
strips, that can be a measurable advantage.

Others have already mentioned visibility issues. High-wing planes give a
better view of the ground for backseat passengers, but low-wing planes give
the pilot better visibility of conflicting traffic in a turn. As a related
point, I have one daughter who gets motion sick easily, so I appreciate not
having to lift my inside wing to check for traffic before turning, the way I
would have to in a high wing. In a low-wing plane you can see the top of
the wing, which is where the ice can accumulate if you stumble into icing
conditions -- that can be a comfort if you fly IFR, but it's not a big deal.

High-wing planes can have a "both" position on the fuel selector, which
simplifies fuel management. Low-wing planes need to use pumps rather than
gravity, so they cannot have a "both" postition, and you have to manage the
fuel more actively: I'd guess that fuel-exhaustion accidents are more common
in low-wing planes (especially with renters who usually fly high-wing and
never touch the fuel selector), but I don't have the stats in front of me.

You can probably extrapolate the answers to these questions from what I've
written above:

Why are most of the more expensive private aircraft (cirrus, pilatus, pretty
much all multi engine and jet) low wings?

Why do all fighters since the biplane era have low wings?

Why do most military transports (C-130, C-17, C-5) have high wings, but all
airliners have low wings?

Why are a lot of cold weather/high altitude planes high wing?

If you're doing most of your flying to proper airports (pavement or
well-maintained grass strips), just pick the plane you like best and don't
worry about the high-wing/low-wing thing. If you're going to do serious
bush work, fly a high-wing taildragger.


All the best,


David

"David Megginson" wrote in message
.rogers.com...
High-wing planes can have a "both" position on the fuel selector, which
simplifies fuel management. Low-wing planes need to use pumps rather than
gravity, so they cannot have a "both" postition

Why not? Mine has one.

Paul
Scottish Aviation Bulldog G-DOGG

"Ray" wrote in message
...
Okay, so all kidding aside, what are the issues between high and low
wings?
I know that in terms of flying, there are very few differences between
your
average Cessna and Piper, but for higher performance aircraft, what are
the
aerodynamic/design tradeoffs?

For example:

Why are most of the more expensive private aircraft (cirrus, pilatus,
pretty
much all multi engine and jet) low wings?

Good thing you said "pretty much", since I co-pilot a Jetprop (Twin
Commander) which is a high wing. :~)

Ray wrote:

Why do all fighters since the biplane era have low wings?

Because attackers will probably be approaching from either the same level or above -
it's difficult to make an effective attack from below. It's also important to be able
to see in the direction of a turn when you turn in to attack an opponent. And not all
fighters are/were low-winged; many were mid-winged aircraft.

Why do most military transports (C-130, C-17, C-5) have high wings, but all
airliners have low wings?

The wing spars have to pass through the fuselage. With a low-wing, that means a hump
in the floor. With a high-wing, that means a lwo ceiling at that point. Planes that
carry cargo would rather have a flat floor to ease loading. People, on the other
hand, will step over a hump in the floor and bang their heads on a drop in the
ceiling.

Why are a lot of cold weather/high altitude planes high wing?

Dunno about "cold weather" planes, but the high-altitude aircraft which come to my
mind are mid-wing aircraft; the U-2 and SR-71.

George Patterson
If you don't tell lies, you never have to remember what you said.