Reading through these forums, it seems that a number of aircraft face limits on engine size due to low ground clearance. This is not a problem faced by large military aircraft such as the B-52, C-17, and AN-124. It seems that a future aircraft design might be able to use a larger turbofan if the wing were higher.
Possible advantages could be a step change in engine diameter, decreasing noise and fuel consumption. It may be possible to decrease the size and weight of the landing gear as well.
On the other hand, some sources claim it would be harder to fuel aircraft. It may be that the wing is expected to stop engine debris from reaching the cabin in the case of catastrophic failures.
What benefits and disadvantages would come from a civil airliner configured this way?
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Re: High Wing Civil Aircraft
I can think of some issues with landing gear placement and weight distribution.
If gear is placed away from fuselage, e.g. in engine gondola like Dash-8, load on wing to body joint is in the same direction in flight and on the groud - but with increase of height, landing gear will grow longer and more complex. Not sure if you can place it on the bottom of big fan without a bit of tricks. Placing gear on the wing, like most modern aircraft, would not be feasible for VERY long gear.
Placing gear in the body, like C-5 or An-124, would lead to varying forces in wing-body joint, probably driving again weight and complexity. Besides, longer cantilever wing also increases structural loads...
If gear is placed away from fuselage, e.g. in engine gondola like Dash-8, load on wing to body joint is in the same direction in flight and on the groud - but with increase of height, landing gear will grow longer and more complex. Not sure if you can place it on the bottom of big fan without a bit of tricks. Placing gear on the wing, like most modern aircraft, would not be feasible for VERY long gear.
Placing gear in the body, like C-5 or An-124, would lead to varying forces in wing-body joint, probably driving again weight and complexity. Besides, longer cantilever wing also increases structural loads...
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- Starlionblue
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Re: High Wing Civil Aircraft
As kalvado says a high wing increases structural weight.
Fueling is also an issue, but I don't think it is a showstopper. The fuelers have to get up pretty high with modern widebodies already.
Modern turbofans are very large, but they're not too large for current mountings. There's a decent amount of clearance under the nacelles. The one design that has issues is the 737, but if that were designed today the gear would be made higher.
I think if you need more clearance at this point, making the gear longer is a much lighter and simpler solution than mounting the wing high.
Fueling is also an issue, but I don't think it is a showstopper. The fuelers have to get up pretty high with modern widebodies already.
Modern turbofans are very large, but they're not too large for current mountings. There's a decent amount of clearance under the nacelles. The one design that has issues is the 737, but if that were designed today the gear would be made higher.
I think if you need more clearance at this point, making the gear longer is a much lighter and simpler solution than mounting the wing high.
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- GalaxyFlyer
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Re: High Wing Civil Aircraft
You refuel the C-5, thru two inlets, standing on the ground, that’s not a problem. Most military high wing planes are designed for “roll on, roll off” loading which is why the high wing.
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