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What are some of the methods used to reduce the drag caused by the landing gear for aircraft with non-retractable landing gear?

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  • $\begingroup$ A flying boat's landing gear imposes no added drag to the airframe. (Sorry, couldn't resist that one!) :-D $\endgroup$ – pr1268 Nov 11 '18 at 6:16
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The Pilot's Manual: Ground School has a nice diagram that explains it pretty well. It's all about streamlining. Airplane designers add landing gear fairings (I've heard them call "wheel pants") over top of the wheels and also on the landing gear strut. Beyond this, there isn't much else to do. The fairings could be made out of single pieces of material to limit the parasite drag introduced by rivets, etc.

Streamlining reduces form drag.

There can be different variations on the fairing, but it pretty much comes down to fairings to reduce the drag:

Finned wheel fairing

NACA (precursor to NASA) details more in REPORT No. 518 THE DRAG OF AIRPLANE WHEELS, WHEEL FAIRINGS AND LANDING GEARS II-NONRETRACTABLE AND PARTLY RETRACTABLE LANDING GEARS

They also looked at wheel shape, but it primarily comes down to creating some sort of streamlined fairing to reduce the amount of eddying.

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One common way is to use wheel fairings:

From wikipedia: wheel fairing

enter image description here

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  • $\begingroup$ Those gear legs need fairings too, typically 3 more pieces. Fairing over the flat gear leg to make it more aerodynamic. Fairing between the gear leg and the body. Fairing between the gear leg and the wheelpant (often called the brake fairing). Look at the Red Bull airspeed racers - all the body part intersections are faired and smoothed for cleaner airflow. $\endgroup$ – CrossRoads Nov 4 '18 at 21:57
  • $\begingroup$ @CrossRoads, they "need" only if it pays. At the extremes like racing everything goes, but for normal use... From memory, the C172 POH (or some other document) mentions that all the wheel fairings improve the cruise speed by 2 kn. Any further improvements (short of retracting) will hardly add another 1. $\endgroup$ – Zeus Nov 5 '18 at 2:19
  • $\begingroup$ Well, the question was about reducing drag, wasn't it? If you didn''t care, you wouldn't 'need' fairings at all. $\endgroup$ – CrossRoads Nov 5 '18 at 4:10
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Paulo Iscold gave a presentation at our EAA meeting last month where he talked about all the ways he investigated to break speed records for piston airplanes. One of the more interesting things that hasn’t yet made into a flying aircraft is to mount electric turbines on the fairings.

Turbine Wheel Fairings

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Here is one way-- no longer in fashion-- I believe these are called "spats"

http://www.airminded.net/alpha/gamma_skch_flt.jpg

from-- and see here for more-- http://www.airminded.net/alpha/gamma.html

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