Aerodynamics of high-winged fighters.

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as i mentioned aerodynamic benefits are difficult to prove - you barely able to said if it is actual benefit of wing location, or just better detailed design, or your manufacturing had better day - of course you may call miracles of CFD and prove this numerically - than just wait as more experienced part of staff will stop laughing...
 
Supposedly wing configuration makes a substantial difference in drag. Long story short, mid-wing aircraft were regarded as having lower interference drag given certain angles of attack. But the reason is more complex than I remember.

I wouldn't normally link to Quora for a WW2 discussion, but the summary in this post is so good I can't help myself.

Low-wing and high-wing had the highest amounts of interference drag because the interaction between the fuselage and the wing position exerts extra drag on the fuselag in high and low-wing configurations. The mid-wing position has the lowest amount of induced drag.

According to this Stackexchange post, there are a lot of other reasons for why a midwing configuration is used on fighter aircraft. The differences relate to production, performance, and structural integrity. Some of the most salient differences include:
  • Lighter weight of the bulkheads that attach to the wing spar.
  • Heavier weight on the carry-through spar in the fuselage
  • Weaker ground effect (negated on a carrier aircraft)
  • Better performance in a roll
  • Poorer visibility while maneuvering
  • Heavier landing gear (unless an inverted gull wing is used)
I always assumed that Grumman used a midwing (or somewhat midwing) configuration on their aircraft for this reason. Although considering that the Hellcat was the slowest Allied fighter of its generation, a midwing configuration couldn't have contributed much in terms of total speed. Although the Hellcat also had a big wing, large profile, and used a non-"laminar" airfoil, so that's probably a big reason why the dash five probably only barely made 400 MPH even with insanely good fuel and a powerful engine.

A high-wing aircraft, on the other hand, is probably more suited for lightweight recon aircraft. The high-wing makes for great downward visibility. But its landing characteristics and interference drag make it a worse candidate for a high performance fighter aircraft.
 
great summary - all i can add is truism that in aircraft design silver bullet not exist and never existed - this is always trade between performance as a flying machine and meeting specific requirements of the user and of course level of technological development - something was bad idea 5 years ago suddenly may become quite reasonable solution.
 

This was known, it was also the reason for the gull wings on the F4U Corsair. The wings joined the fuselage at near to 90 degrees for very little induced drag, or at least not much more than the mid-wing design. Of course now they had to bend the wing up and deal with those problems.
It may be possible that the gull wing fighters got a similar benefit rather than having the wing at the level of the top of the fuselage?
 
There's one big problem with mid-wing transports: the wing spar goes right through where the passengers and cargo would be carried.

The big disadvantage of high wings for fighters is packaging. The best place for the pilot is near the c/g (at the c/g, the pilot will face the least possible accelerations during maneuvers.) which would be vertically below or above the wing, although the former has the problem of severely restricting visibility.
 

Thanks so much, this is the sort of dope I was looking for.
 
A high-wing aircraft is inherently more stable, which isn't always a good thing for a fighter. Look at the Harrier, and the amount of anhedral it has to make it less stable, and more manoeuvrable.

(edited to change the reference to high-wing)
 
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I feel I must disagree as a flying modeller and amateur aerodynamitist, the high wing is more stable in flight. The parasol wing layout, more so. The basic pendulum effect is in play. That's one reason why an inverted spin in a low wing plane is more difficult to recover. The center of gravity wants to stay below the mainplane. Allegedly, why biplanes are better trainers for spin recovery. Very few modern civil basic flying school planes are low wing. Some on this forum have negative comments about Cherokee types for training.
 
Sorry, typing on phone while tired - I meant to type high-wing....

And I agree with everything you wrote here, except for the training thing. I've spun high-wing, low-wing and bi-planes. both the low-wing and bi-plane would happily sit in the spin all day, but weren't overly difficult to get out of the spin.
People's aversion to Cherokees for training seems to be around the fact that they aren't spin-approved. I did my commercial licence in one and had no problems with it.
 
A high-wing aircraft is inherently more stable, which isn't always a good thing for a fighter. Look at the Harrier, and the amount of anhedral it has to make it less stable, and more manoeuvrable.

(edited to change the reference to high-wing)

The Harrier -- and other high-winged aircraft with swept wings -- will frequently have anhedral because the effective dihedral of a swept wing increases with angle of attack, which can lead to unpleasant behavior on approach and high angles of attack. Many swept wing aircraft with dihedral exhibit a bounded stability, Dutch roll, which is, at a minimum, uncomfortable for the various souls aboard. Usually, this is dealt with by installing a yaw damper.
 
Did Grumman maybe go for mid-wing because the fuselage-mounted landing gear they used on the previous FF,F2F and F3F was something they knew how to do? Nearly all other WW2 single-engine fighters went with low wings. Hellcat was barely -mid, F2A mid but spread the gear out over wing and fuselage, what else? Komet? Well, that's a special case.

Parasol wings had a little period in vogue in WW1, mount the wing in front of the pilot and level with his eyes. However with a narrow track and a high wing and a tailwheel you have a potential ground stability problem. Anyhow, there was no payoff in WW2 for high wing.
 
Many naval types (or attack types) were designed mid-wing:
Fairy Barracuda, Brewster SB2A, Curtiss SB2C, Yokasuka D4Y, Vultee A-31, Douglas BTD, Aichi B7A, etc.
 
The ideal wing joint is at 90 to the hull - strongest, lowest drag, see the F4U Corsair.

My question in the OP was about aerodynamics specifically. "Lowest drag" does address that in one sense. I was curious whether or not the wing location mattered for maneuverability itself. S special ed with his mention of the pendulum effect on stability helped me understand a bit more, and it makes a lot of sense. Swinging around a lot of airplane below the lifting plane has to act as a dampener. Ed, is that in the ballpark?
 
A lot of people were guessing in the 1920s and 30s. I don't think the first aeronautical engineer graduated school until the mid 20s?
Go back to post #16 and Lockheeds. Identical or similar engines, identical horizontal stabilizers and elevators, Identical or very close vertical stabilizer and rudder.
Wing was nearly identical in size, planform and airfoil.
Lockheed didn't claim to know (at least at the start), they would build what ever the customer wanted based off the customers wants/believes.
There may well be textbooks from aeronautical courses that cover this.
 
Yes. The pendulum effect is best understood by free flight modelers. If the plane is to fly only by the trim and forces of the thrust, I.C. engine or rubber, then it must be as stable as possible when launched or released from the ground/water. I don't normally build free flight models as they require more aeronautical knowledge than I have. In general, when under power it should make a gentle climb to right or left depending on engine rotation and when out of fuel or if controlled by a timer fuel shut off, it should develop a gentle spiral glide opposite rotation to the climb and make a good landing. If the wind and other natural forces leave it alone, a perfect landing is hoped for. My Bf 109 (about 20 inch span) began a quick torque roll into the wind where it found excessive lift, made about a 40 foot loop (I ducked), then went into a series of short climbs and stalls. It was too heavy anyway. The most impressive free flight I made that comes to mind was a Monogram Speedy-built MiG-15 powered by a Jetex unit, a miniture solid fuel rocket. It had been trimmed for long proper glides and when ready to "light th fire" it made a perfectly flat hand launch entering to an approximate 100 ft loop, finished level upright at about 20 feet and moving much faster than we could run, moved out straight , flat and level. We were running after it because we noticed near the top of the loop, a whisp of smoke, and while flying away from us, it turned into a very heavy smoke trail. It looked remarkably similar to the gun camera shots from Korea. The glide was perfect as it belly landed with rear fuselage in flames. I stayed with control line models for the next 67 years.
 
it is matter of design standards - in those days PZL design team have used 1.4 safety factor vs.1.5 being used in germany
Actually P.1 and P.7 had so strong wing (around 20 g), that the following models didn't need to increase strength as their weight was growing up.
In practice pilot didn't need to think about structural strength in any circumstances.
P.11c had diving limit 600 kph IAS while having very draggy airframe.
And was extremely resistant to battle damage.
Major factor for preference low wing layout is huge weight saving over high wing layout (i mean single engine, propeller driven and high performance airplanes in other cases trade may looks different).
It is simply not true. High wing allows to use struts that save a lot of weight.
next thing is that Polish designs lacked all necessary safety features - no inertial gas installation, no armour, no fire extinguishing system, no self sealing fuel tanks
No contemporary fighter had them. In case of P.1-P.24 line the opposite is true: the main fuel tank was detachable in emergency situations, so they were the safest fighters of the era in the case of fire. Greece P.24 got armored windshield and armored plate behind pilot.
 

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