41
$\begingroup$

What are the advantages and disadvantages of a high-wing vs. low-wing aircraft design? When might one prefer one to the other?

Is the answer the same for large and small aircraft?

$\endgroup$
33
$\begingroup$

This is actually a really hard question to answer, as there are a ton of factors. I'll try to cover a few.

  • Visibility is probably the reason you most hear when it comes to GA pilots.
    • High-wing aircraft offer better visibility below the aircraft, especially for passengers in 4-seat or larger aircraft, as the wing doesn't block it.
    • Low-wing aircraft can offer better visibility above the aircraft, as the wing remains mostly out of the field of view.
    • Note that a lot of midair collisions involve mixed types; low-wing aircraft descend into high-wing, or high-wing aircraft climb into low-wing.
  • Landing characteristics are different, as low-wing aircraft can incur more ground effect than high-wing.
  • Aerodynamic stability of the two designs differs a bit; the center of lift can be higher in a high-wing design, often offset with dihedral in low-wing aircraft.
  • Ground clearance (and debris protection), specifically in multi-engine aircraft, is going to be greater when engines are mounted on a high wing rather than a low wing. This is true of both propeller and jet engines, although propellers tend to have a larger radius for a given aircraft size.

There are a bunch more, but that ought to get the argument discussion going.

$\endgroup$
  • 4
    $\begingroup$ On the topic of visibility: when turning, high wings tend to block your view in the direction you are turning. $\endgroup$ – sdenham Jun 12 '14 at 16:31
  • $\begingroup$ a lot of noise is made around flights schools regarding high-wing versus low-wing accidents but I've never seen any evidence. $\endgroup$ – rbp Nov 24 '14 at 22:05
  • $\begingroup$ @rbp Yeah, there are plenty of high+low combo accidents out on record. That's the only configuration-related accident info I've seen. $\endgroup$ – egid Mar 13 '15 at 19:01
  • $\begingroup$ Are there advantages of high-wing in terms of aerodynamic efficiency (lift over drag)? $\endgroup$ – Jonny Apr 27 '15 at 7:16
10
$\begingroup$

@Egid, your already gave really good and correct answer dealing with the most important benefits and downsides, or simple the most significant differences. I like to follow your invitation and add the differences I thought of and you have not already mentioned:

The additional ground clearance also benefits the maximum crosswind some high-wing aircraft can cope with, what in my eyes is also an important point.

Also high wing aircraft - talking about light sports - benefit the design of the fuel system as it allows consumption from both tanks simultaneously without installation of additional fuel pumps - this is not only a benefit for lazy pilots but has probably already prevented some accidents.

Now somebody needs to tell me why I'm flying low-wing ;)

$\endgroup$
  • 4
    $\begingroup$ Cause low wing planes look so much cooler? :) $\endgroup$ – Jeremy Logan Jan 10 '14 at 15:06
  • 1
    $\begingroup$ I guess that's it :D $\endgroup$ – Falk Jan 10 '14 at 21:57
  • 1
    $\begingroup$ Just had a thought, are there any low wing tail draggers? Hmm, I'll ask in chat. $\endgroup$ – CGCampbell Jun 23 '14 at 0:04
  • $\begingroup$ I guess there are some old fighter planes. $\endgroup$ – Falk Jun 23 '14 at 1:36
  • $\begingroup$ The DC-3/C-47 is a low wing tail dragger. There are others, but they are generally 1930's era aircraft. $\endgroup$ – Skip Miller Jul 22 '14 at 14:38
7
$\begingroup$

Low wing aircraft also benefit that in a crash, much of the crash energy can go into the wings instead of into the fuselage.

$\endgroup$
6
$\begingroup$

Low wing aircraft have the advantage in a water landing because the wings can keep much of the fuselage above water, as well as provide a temporary staging area for deplaning passengers. In a high aircraft, you would be lucky to get out before drowning.

Likewise, on land, low wing aircraft are easier to control in a wheels up landing.

Low wing aircraft can be designed with a more widely spaced and shorter main gear, which is more stable. Most high wing aircraft use fuselage sponsons (MU2, ATR-42/72, Do228/328, BAe-146/Avro RJ, C-130) to house the main gear, providing a relatively narrow, and therefore, less stable track. For those high wing designs that house the main gear in wing-mounted engine nacelles or in the wings themselves (Twin Commander, F-27/227, Dash 7/8, B-24/32), the gear must be made much longer, and therefore, much heavier. A long main gear design is also more prone to structural failure in a hard or poorly executed crosswind landing.

Low wing aircraft are easier to refuel, and if equipped with wing-mounted engines, those would be easier to service.

$\endgroup$
4
$\begingroup$

Another factor is fuel flow (at least in small GA planes).

Lets compare a Cessna 172 to a Piper Cherokee. The Piper is low wing and requires a fuel pump (engine driven with an electric backup) to flow the gas from the wing tanks up to the engine. This add not only adds another part that can fail but the possibility that you can vapor lock the system if you run it dry. In a the Cessna (high wing) the fuel is pulled by gravity, out of the wing tanks, and into the engine much like an old car (1930's era). This eliminates the fuel pump and the vapor lock issue which some people find quite nice. At this point I am well into the habit of switching tanks every 30 minutes.

A note should be made that some Cessnas (from what I have read) do have fuel pumps now but I don't fly them so I don't know a lot about the newer model specifics.

High wing airplanes also prove to be advantageous if you are flying a lot of back country stuff. The added clearance can help you land in bushy areas or other less hospitable places where a low wing plane might strike something.

The best answer to this question can usually be found at your local airfield. Ask a guy that owns a Piper (just not a Cub), then ask a guy that owns a Cessna (just not the 400), and decide for your self based on their answers.

$\endgroup$
  • $\begingroup$ On the other hand, aircraft with gravity-fed fuelsystems can't fly inverted without the engine dying. $\endgroup$ – Sean May 2 '18 at 3:03
  • 1
    $\begingroup$ @Sean very true, for that matter most tanks are gravity fed to at least their low point (and then it may be pumped higher) making most standard fuel systems improper for inverted flight. $\endgroup$ – Dave May 2 '18 at 4:28
4
$\begingroup$

Here are a couple of ground comfort related differences.

When it's hot, and you're waiting in line for fuel, or if your plane isn't hangared, you can stand in the shade under a high wing.

If you want to walk from fore of the wing to aft of the wing, to get the oil rag you forgot, with a high wing, you duck a bit and walk straight, with a low wing, you walk all the way around the wing. Twice.

$\endgroup$
  • $\begingroup$ My first downvote. :( I sstill think it's a good answer. $\endgroup$ – Greg Taylor Dec 21 '15 at 15:11
2
$\begingroup$

A quick addition to the previous answers:

Larger commercial aircraft also capitalize on the low-wing's benefits from a maintenance perspective.

$\endgroup$
  • 3
    $\begingroup$ Large commercial aircraft have low wings to stow away their long landing gears. Long gears make it possible to stretch the fuselage and still be able to rotate during take-off. Large high-wing aircraft with their low fuselage position are easier to load and unload, at the price that the fuselage taper has to start shortly aft of the landing gear, so no stretching is possible. $\endgroup$ – Peter Kämpf Jul 21 '14 at 20:11
  • $\begingroup$ @PeterKämpf, are there advantages of high-wing in terms of lift versus drag (aerodynamic efficiency) performance? $\endgroup$ – Jonny Apr 27 '15 at 7:17
  • $\begingroup$ @Jonny: The best is a mid-wing configuration. High wings have less dihedral, so less lift is lost as side force. But the difference is small. If you want to know more, why not post a new question here? $\endgroup$ – Peter Kämpf Apr 27 '15 at 12:13
2
$\begingroup$

Another factor with low-wings is that on take off and landing, the low wing will block airflow over the empennage, reducing rudder and elevator effectiveness. That's why so many low-wings have T-tails, to keep the tail in the flow of air during landing and takeoff.

$\endgroup$
  • $\begingroup$ This is true not just of takeoff and landing but of any higher-AoA situation, for what it's worth. $\endgroup$ – egid Nov 25 '14 at 0:25
  • $\begingroup$ yes! hopefully you're not flying high-AOA during other flight regimes, except for training $\endgroup$ – rbp Nov 26 '14 at 13:14
  • $\begingroup$ why is this worse with a low wing than a high wing? $\endgroup$ – Peter Nov 27 '14 at 1:04
  • $\begingroup$ because in a high wing, the airflow at high AOA is above the wing. in a low wing, the wing blocks the airflow to the tail: upload.wikimedia.org/wikipedia/commons/2/24/… $\endgroup$ – rbp Dec 1 '14 at 18:06
  • $\begingroup$ i know these pictures aren't perfect, but they give you an idea: airport-data.com/images/aircraft/small/000/255/255722.jpg Here's a T-Tail arrow departing (start at 40 seconds -- youtube.com/watch?v=cbzhaSp-MEs) $\endgroup$ – rbp Dec 1 '14 at 18:10
2
$\begingroup$

Let me add one more advantage/disadvantage pair.

High-wing aircraft (at least for small GA aircraft) may be easier to preflight as wing fuel drains are more accessible and it is easier to examine the underside of the wing (flap linkages, aileron hinges, skin, possible fuel leakages). Personally, I'm tall enough to be able to see the top of the wing without a ladder, but I'll admit that this advantage shrinks for shorter pilots. The downside is ease of refueling (and sticking the fuel tanks). A Cherokee (low-wing) doesn't require a ladder to refuel whereas we carry a stepladder in our club Cessnas.

$\endgroup$
  • 1
    $\begingroup$ Another advantage of low wing over high wing is that I've never bashed my head on a low wing. $\endgroup$ – jamesqf Mar 14 '15 at 5:03

protected by Farhan Mar 12 '15 at 18:54

Thank you for your interest in this question. Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).

Would you like to answer one of these unanswered questions instead?

Not the answer you're looking for? Browse other questions tagged or ask your own question.