High wing vs low wing efficiency

Briar Rabbit

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Rob
Get the popcorn ready.

My opinion is that high wing location is generally more efficient than low wing if the wing design itself is comparable for two reasons. Meaning same chord, taper, design etc. being totally identical (which they never are from airplane manufacturer to manufacturer). So for this discussion not saying that any particular high wing is more efficient than all low wings but in general a high wing location has two benefits not available to low wing designed airplanes.

First it has some benefit from the reduced dihedral required with the wings being located on top. When it is necessary to increase the dihedral (low wing aircraft) the lift vector perpendicular to the wing angled more does not provide as much lift as a wing with minimal amount of positive dihedral and the vertical vector effectively longer.

Second it is well known that roll rate performance increases as dihedral moves away from positive dihedral and the wings move toward negative dihedral. Case in point all great fighter aircraft such as the F-18 have negative dihedral. During Vietnam I was told the old A-7 built by LTV had such negative dihedral it was nearly unflyable if the black boxes failed but the increased roll rates matched up better in the early part of the war when dogfighting the Migs. The point is with less dihedral required in high wing aircraft wouldn't they tend to have better roll response and inherently more efficient to fly?

Now not saying the benefits of high wing aircraft providing more shade in the summer, generally have two doors vs one and flying visibility to the ground should be ignored. Nor that low wing aircraft are typically easier to land and also easier to fuel, also viable points and personal taste to be considered. Just that high wing location by itself tends to make a more efficient single engine design?

I can think of many large multi engine military aircraft with high wings (C5A, C130, C141, etc) but not many large commercial air carriers. Is the landing gear too costly to design for a high wing large multi engine airplane? Boeing influence too predominate? Why not many large commercial high wing airplanes anymore?
 
What if you are upside down?


What if you are upside down on a treadmill?
 
No contest. It's waaaaay more efficient to refuel my low wing. :D
High wings suck...except when you want to get yourself and the fly rod into the back country (after the fuel tanks are topped off). ;)
 
High wing! On a hot day you’re sitting in the shade.

Plus we all know the Almighty Creator is a high wing fan. Has anyone seen a bird in the tree that was a low wing? :D
 
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Get the popcorn ready.

My opinion is that high wing location is generally more efficient than low wing if the wing design itself is comparable for two reasons. Meaning same chord, taper, design etc. being totally identical (which they never are from airplane manufacturer to manufacturer). So for this discussion not saying that any particular high wing is more efficient than all low wings but in general a high wing location has two benefits not available to low wing designed airplanes.

First it has some benefit from the reduced dihedral required with the wings being located on top. When it is necessary to increase the dihedral (low wing aircraft) the lift vector perpendicular to the wing angled more does not provide as much lift as a wing with minimal amount of positive dihedral and the vertical vector effectively longer.

Second it is well known that roll rate performance increases as dihedral moves away from positive dihedral and the wings move toward negative dihedral. Case in point all great fighter aircraft such as the F-18 have negative dihedral. During Vietnam I was told the old A-7 built by LTV had such negative dihedral it was nearly unflyable if the black boxes failed but the increased roll rates matched up better in the early part of the war when dogfighting the Migs. The point is with less dihedral required in high wing aircraft wouldn't they tend to have better roll response and inherently more efficient to fly?

Now not saying the benefits of high wing aircraft providing more shade in the summer, generally have two doors vs one and flying visibility to the ground should be ignored. Nor that low wing aircraft are typically easier to land and also easier to fuel, also viable points and personal taste to be considered. Just that high wing location by itself tends to make a more efficient single engine design?

I can think of many large multi engine military aircraft with high wings (C5A, C130, C141, etc) but not many large commercial air carriers. Is the landing gear too costly to design for a high wing large multi engine airplane? Boeing influence too predominate? Why not many large commercial high wing airplanes anymore?

The A7 was not a black box aircraft as far as the flight controls. It also was a ground attack aircraft not a fighter so rarely engaged migs and the normal response to a mig was to dive for the deck and run. It’s roll rate was ok but not spectacular like the aircraft it replaced the A4. I think you might be confusing it with the F8 which it was derived from. The F8 did better than most other US fighters in the war mostly because they never abandoned the dogfight concept and trained for that unlike more advanced US fighters. (F4). The F-18 at least the A/C models had a crappy roll rate especially at high speed where the wing would twist with roll inputs.
 
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Why not many large commercial high wing airplanes anymore?
With mixed load (people and their luggage), low wing seems to make the most sense. The customers get a good view, while bags and cargo ride under the floor, the wing spar is tucked away out of sight, and the landing gear is reasonably short.

The East Germans tried to cobble a commercial airliner (Baade 152) out of a high-wing bomber design.

Baade 152 01.jpg
 
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Don't mind me, just waiting for Nauga to come along................. ;)

a01e818e2022bd65061a42173d40b5d9.gif
 
With mixed load (people and their luggage, low wing seems to make the most sense. The customers get a good view, while bags and cargo ride under the floor, the wing spar is tucked away out of sight, and the landing gear is reasonably short.

The East Germans tried to cobble a commercial airliner (Baade 152) out of a high-wing bomber design.

View attachment 92891
The people in the first row had a really nice view.
 
Get the popcorn ready.

My opinion is that high wing location is generally more efficient than low wing if the wing design itself is comparable for two reasons. Meaning same chord, taper, design etc. being totally identical (which they never are from airplane manufacturer to manufacturer). So for this discussion not saying that any particular high wing is more efficient than all low wings but in general a high wing location has two benefits not available to low wing designed airplanes.

First it has some benefit from the reduced dihedral required with the wings being located on top. When it is necessary to increase the dihedral (low wing aircraft) the lift vector perpendicular to the wing angled more does not provide as much lift as a wing with minimal amount of positive dihedral and the vertical vector effectively longer.

Second it is well known that roll rate performance increases as dihedral moves away from positive dihedral and the wings move toward negative dihedral. Case in point all great fighter aircraft such as the F-18 have negative dihedral. During Vietnam I was told the old A-7 built by LTV had such negative dihedral it was nearly unflyable if the black boxes failed but the increased roll rates matched up better in the early part of the war when dogfighting the Migs. The point is with less dihedral required in high wing aircraft wouldn't they tend to have better roll response and inherently more efficient to fly?

Now not saying the benefits of high wing aircraft providing more shade in the summer, generally have two doors vs one and flying visibility to the ground should be ignored. Nor that low wing aircraft are typically easier to land and also easier to fuel, also viable points and personal taste to be considered. Just that high wing location by itself tends to make a more efficient single engine design?

I can think of many large multi engine military aircraft with high wings (C5A, C130, C141, etc) but not many large commercial air carriers. Is the landing gear too costly to design for a high wing large multi engine airplane? Boeing influence too predominate? Why not many large commercial high wing airplanes anymore?
I once saw a graph by @wanttaja in one of his articles on homebuilt safety factors.
See Figure 5 in this link (need to scroll down): https://www.avweb.com/flight-safety/risk-management/homebuilt-accidents-fatal-factors/
I noticed that most of the high-wing planes were at the lower speed range- cruise speed below 130 mph, and only one near 200 mph. I realize correlation is not causation. Maybe the high-wing planes are easier to build for light structures that are under less stress at lower speed. High-wing planes at high speeds tend to be the exceptions. Maybe they are just easier and cheaper to build, as alluded to earlier. Or maybe high-wing are more efficient at lower speeds, including birds, and low wing are more efficient at higher speeds?
I don't know.
 
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Neither!

Mid wing for the win! Get the worst of both in one design
5cd0dcd9d4249faaa31391e368cd0693.jpg
 
I once saw a graph by @wanttaja in one of his articles on homebuilt safety factors.
See Figure 5 in this link (need to scroll down): https://www.avweb.com/flight-safety/risk-management/homebuilt-accidents-fatal-factors/
I noticed that most of the high-wing planes were at the lower speed range- cruise speed below 130 mph, and only one near 200 mph. I realize correlation is not causation. Maybe the high-wing planes are easier to build for light structures that are under less stress at lower speed. High-wing planes at high speeds tend to be the exceptions. Maybe they are just easier and cheaper to build, as alluded to earlier. Or maybe high-wing are more efficient at lower speeds, including birds, and low wing are more efficient at higher speeds?
I don't know.
Maybe most high wing airplanes trace their lineage to something that was designed to get in and out of a pasture, and the wings had to clear the fence posts.
 
From a 1961 Cessna ad:

View attachment 92890

:D

Well, the thread title was about "efficiency", not stability. :D

But I have to concede, there may be something to this "high-wing-more-efficient" thesis. :idea:
It's difficult not to notice so many efficient high wing airplanes need those under-wing tie-down struts to keep the massive lift they generate from ripping off the wings upward...
 
Neither!

Mid wing for the win! Get the worst of both in one design
5cd0dcd9d4249faaa31391e368cd0693.jpg
Ah, that would be a great aircraft. Fun fact, a few weeks ago while dreaming of plane ownership I jokingly told my wife it seemed like you could get a decent multi engine aircraft for about the same cost as some of the popular single engine aircraft. She goes on trade a plane and an Aerostar is the first thing she pulls up and she loves the look, shows it to me and I respond with -eh, that looks a little weird. Then I did some research just for fun and now I want one. Just need a multi engine and IFR rating so I can fly it.
 
Why hasn't anyone mentioned the B-2 or YB-49?

(apologies if I missed it)
 
From my point of view, the wing position is mostly dictated by practical considerations (access, loading, runway types, gear, etc) and esthetics. The most direct comparison I can think of in light GA is sling tsi
https://www.customaircraftbuilders.com/sling-high-wing/

h
igh wing is a little larger, a little slower, and a little more useful load and range
 
High wing can use a thinner wing section and a strut for the less weight compared to a cantilever low wing.
Mid wing will usually be more efficient aerodynamically.
Interference drag tends to be higher with high wings. Tends.
High wing retracts suck.
If you cantilever the wings, the carrythrough is sometimes easier with a low wing.
Low wings can be more floaty.
The first cantilever wing airplane was built by Junkers in 1915. It was also the first all metal airplane.
The first aircraft with a "modern" thick airfoil (with a flatish bottom and curved top) and cantilever wings was the Fokker V-4 Triplane. Interplane struts were added for the production DR1 to reduce wing flex. 1917
The cartoon airfoil with flat bottom and curved top that everyone draws when they "explain" lift was pretty much obsolete by the 1930's.
 
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The A7 was not a black box aircraft as far as the flight controls. It also was a ground attack aircraft not a fighter so rarely engaged migs and the normal response to a mig was to dive for the deck and run. It’s roll rate was ok but not spectacular like the aircraft it replaced the A4. I think you might be confusing it with the F8 which it was derived from. The F8 did better than most other US fighters in the war mostly because they never abandoned the dogfight concept and trained for that unlike more advanced US fighters. (F4). The F-18 at least the A/C models had a crappy roll rate especially at high speed where the wing would twist with roll inputs.
You are correct, had it confused with the F8 which looks similar, also built by LTV and initially was successful against the MIG 17’s at the early part of the war. It has been a long time since engineering school but I do remember the A7 being used as an example of airplanes with negative dihedral (or more correctly anhedral) having improved roll rates and that the first flight demonstration of the A7 impressing onlookers with fast roll rates even though loaded with more than 7,000 lbs of ordinances on the pylons. Another example discussed at the time was the designers having to change the wing tips of the F4 because it was not adequately stable. This change is called a polyhedral wing. Interestingly swept wing designs also increase some degree of roll stability.

Anyway I am still curious why there have not been many high wing commercial air carrier airplanes? If the 737Max had been a high wing design it would not have been necessary to move the engines forward and try to correct the flight issues with the disastrous MCAS system.
 
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