Why were these airplanes designed differently, and what are the advantages of each type of wing location?
The origins of design philosophy often go back to the personal tastes of a guiding hand at the head of a company, perhaps in coordination with marketing and engineering input. Once an aircraft is certified the design is frozen, so many of the airplanes we fly today are updated variations of aircraft designed 20 years ago or longer. Change comes slowly in aviation, and a company's use of high or low wing placement isn't likely to change. The comforting thing about this reliance on antiquity is that the designs have proven to work well, and any bugs have been exterminated after years in service.
Which way should you go?
Personal tastes of the designer aside, there are valid reasons to have the wings attached to the fuselage in either of these different ways. A low-set wing gives the nonpilot passengers a comfortable feeling of solid support when they look out the window, leading them to think that they are being held aloft by substantial structure rather than thin air.
Because most airliners feature low wings, there's a trendy cachet to a low-wing lightplane that has marketable value. Most manufacturers of low-wing airplanes term their wing placement a "modern" design, even though placing the fuselage atop the wing goes back to the earliest days of monoplane construction. Lockheed built both high- and low-wing single-engine airplanes in the 1930s that employed the same fuselage, giving the customer a choice of styles.
The high-wing design opens up the view of the world passing below, and it offers shade and shelter for the passengers. Navigation by the use of pilotage may be somewhat easier with the unobstructed visibility of a high wing, but there are plenty of viewing angles available from the pilot's seat of a low-wing airplane; only the section of landscape directly beneath the wing is hidden, and it will reappear in a few seconds as the aircraft moves across the ground. (In some low-wing designs, such as Socata's Tampico trainer, the leading edge of the wing is so far aft that the pilot's downward view is barely restricted.)
In the traffic pattern, the high-wing airplane allows a student to see the runway more easily from a downwind leg location--while the low-wing pilot has an easier time rolling out onto a base leg with a proper 90-degree alignment, because he or she can keep an eye on the runway during the turn. High-wing pilots learn to make traffic pattern turns expeditiously so that they can regain a view of the airport as soon as possible.
Keeping an eye out for conflicting traffic can be problematic no matter which style of wing you're flying. Low-wing airplanes offer a better view of the sky above the horizon--except in the area above and behind the cabin, particularly to the pilot's right. High-wing designs, on the other hand, permit a view of traffic from just above the horizon to everywhere below it--except for a blind spot behind the right side of the instrument panel.
The truth is, all airplanes have limitations on the pilot's field of vision that must be accommodated. No matter which type you're flying, you always should take a good look to clear the airspace you're about to occupy before you enter a turn. It's a good idea to bank the wing out of the way briefly--up for a high-wing airplane and down for a low-wing design--before beginning a turn. Although the low-wing airplane allows you to continue looking for traffic in the direction of your turn after you've entered a bank, you don't want to initiate a turn until you've looked.
By now, we've established that either wing placement works well, and it's possible to use either type as a training vehicle. From a performance standpoint, the lowest drag results from placing the wing midway up on the fuselage, but aerodynamic solutions are available for any drawbacks that result from placing a wing above or below the cabin. There is a certain amount of interference drag as air flows along the juncture of the wing and fuselage; less disruption results from a clean mid-wing design, followed by the high-wing position. A low-wing airplane also works fine, perhaps with a fairing or fillet added to smooth airflow above the wing near the fuselage.
One obvious difference is the amount of dihedral built into the wing; low-wing airplanes have a lot more of the upward angle that causes the wing tips to be slightly higher than the wing roots. Dihedral is needed to give the airplane lateral stability, a self-righting tendency if it is disturbed from wings-level flight; during a sideslip, the angle of attack is greater on a lowered wing, tending to push it back to equilibrium. Dihedral also gives the rudder an ability to "pick up" a lowered wing with a nudge of yaw added by the pilot, enhancing lift on the down wing. Because high-wing airplanes have a pendulum of weight concentrated below the wing, they don't need as much dihedral to enjoy the inherent stability desired for all airplanes.
The fact is, both wing types fly about the same, after all of the design work is done.
Benefits and detriments
There are advantages and disadvantages to each wing placement. The low wing makes an obvious place to attach the main landing gear, usually resulting in a wider stance that improves stability in taxiing. A low center-of-gravity on the ground makes it easier to negotiate strong winds with the wide gear. A low wing's fuel supply, usually in wing tanks, is simpler to check during preflight with eye-level filler caps. The sump drains, on the other hand, are awkward to reach under a low wing, requiring a duck-walk maneuver.
High-wing airplanes have exactly the reverse fuel challenges; the sumps are easy to drain, but you'll have to find a ladder or use tiny steps and handles on the airplane in order to see what's in the tanks.
The high-wing airplane's advantages include gravity-fed fuel flow, so there's no requirement for a back-up electric fuel pump other than for starting. Big flaps can be fitted without concern about ground clearance, and for ground operation in the bush the high wing easily clears posts, snow piles, brush, and boulders that might be a hazard to low-wing aircraft. Having the main gear attached to the fuselage means the wing structure is spared the stress of takeoff and landing. In most cases, amenities like large doors and windows that open are easier to engineer with a high wing.
Learning the truth
Flying an airplane is the same no matter where the wing is located. Individual airplane types may have characteristics to be learned that aren't associated with the wing placement, such as a high power-off sink rate or a placard warning against slips when the flaps are extended. It will take five to 10 hours of transition time to get used to the weird feelings of having the main wheels hidden under a wing during landing or having to raise a wing to see above it in flight. It's always awkward to learn a new cockpit arrangement and the feel of a new set of controls, but it's simply of matter of getting acquainted.
Which one is best for training? Given all the other factors that go into choosing a flight school, like convenient location, friendly staff, rates, and reputation, the high-wing-versus-low-wing debate is really a minor consideration. Either one will work suitably well. If a school offers both types of training aircraft, some students will take an introductory flight in each, to see if they have a preference. If you really can't make up your mind, you can always try to find a school that uses biplane trainers; then you'll have both a high and low wing.
LeRoy Cook has been an active flight instructor since 1965 and has had more than 1,350 articles published. He is the author of 101 Things to Do With Your Private License.
LeRoy Cook
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