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All gliders / sailplanes seem to use a single central stick to manipulate the primary control surfaces. In other airplane types, we also find yokes and sidesticks. Are there any glider designs, historic or modern, which do not have a central stick but instead use a yoke, sidestick, ...? Why (not)?

For the purpose of this question, Touring Motor Gliders (TMGs) and cargo gliders are out of scope.

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    $\begingroup$ The Gimli glider had one ;-) $\endgroup$
    – Jim
    Dec 25, 2022 at 21:42
  • $\begingroup$ Does this describe a glider? "From the linked page above, "On March 5, 1950, Bob was flying his P-38 and took advantage of this little understood weather phenomenon to try something new. He soared the P-38 with both engines dead and propellers feathered for more than an hour between 13,000 feet and 31,000 feet. Maximum climb rate was 3000 feet per minute."" Source -- aerosente.com/2009/04/the-sierra-wave-project.html -- also widely described elsewhere. ; ) $\endgroup$
    – quiet flyer
    Dec 25, 2022 at 22:04
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    $\begingroup$ Would any of the Horten gliders qualify? None of them had a central stick, all used a side-mounted stick. $\endgroup$
    – Peter Kämpf
    Dec 26, 2022 at 2:04
  • $\begingroup$ @PeterKämpf Yes, feel free to add your answer ;) $\endgroup$
    – Sanchises
    Dec 26, 2022 at 6:38
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    $\begingroup$ @Jim Arguably the Gimli glider was just a large TMG... $\endgroup$
    – Sanchises
    Dec 26, 2022 at 6:38

3 Answers 3

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Are there any glider designs, historic or modern, which do not have a central stick but instead use a yoke, sidestick, ...?

The Schreder HP-18 sailplane, offered as a kit to homebuilders, was designed with a sidestick. I've seen one "in the flesh". Some have now been converted to a central stick, and some were originally built that way.

One can easily see why a sidestick could be an advantage in a sailplane with a very slender cockpit, with the pilot seated in a prone position-- there would be less of an issue with the pilot's legs limiting the stick travel-- but there are some ergonomic disadvantages as well.

The Applebay Zuni sailplane also featured a sidestick. In this glider, the sidestick's fore-and-aft-motion was accomplished by sliding rather than by pivoting (the same may have been true of the HP-18's sidestick), and the "breakout" force or static friction that needed to be overcome to move the stick in the pitch direction was rather high. This made it more difficult to control the glider at high airspeed-- the pilot could accidentally impose a high G-load when intending to only make a small input-- which may have contributed to a fatal accident.1

"Shifting gears" a bit, ultralight sailplanes that are designed to be foot launchable are usually equipped with sidesticks. The necessity for the pilots legs to be able to hang out the bottom of the aircraft makes a sidestick much more logical choice than a center stick. Many of these aircraft may also be aerotowed, utilizing wheels rather than the pilots legs, and thus are functionally equivalent to more conventional sailplanes. Motorized self-launching versions of many these aircraft also exist (again utilizing wheels rather than the pilot's legs for landing gear), and retain the sidestick configuration. Examples of foot-launchable ultralight sailplanes include the Aerianne Swift and its Bright Star predecessors, the Bright Star Millenium, and the Ruppert Archaeopteryx.

Another class of gliders that usually have sidesticks are those where the pilot flies from a prone position. Historical examples include the wings of the Horten brothers, several of which were flown in soaring competitions. A modern example that would fit the description of a "recreational glider" is the ATOS "Cage" ultralight sailplane. The "Cage" evolved from the line of ATOS rigid-wing hang gliders in which the pilot is suspended prone below the wing with his hands on a triangular "control frame". The "Cage" uses wings from the "ATOS" hang glider series, but moves the pilot up into an enclosed fuselage between the wings, while retaining the prone position.

As for control yokes-- in modern high-performance sailplanes, where the pilot is seated in a semi-recumbent position in a slender fuselage, space is at a premium. A control yoke takes up more space than a control stick, and so a control stick is the better design choice.

Footnotes:

  1. Source-- anecdotal information from long-time sailplane pilot familiar with the incident. The accident is is also mentioned-- with no cause offered-- in the last link below.

Links:

Article on Schreder HP-18 in National Soaring Museum collection (mentions side-mounted control stick)

Wikipedia entry on Schreder HP-18 sailplane (mentions side-mounted control stick)

Link to a center-stick conversion kit for Schreder HP-18 sailplane

Link to an interesting article about a highly modified HP-18

Wikipedia entry on Applebay Zuni and Zuni 2 sailplanes (mentions side-mounted control stick on Zuni, and notes that it was replaced with a center stick on the Zuni 2 "to remove unwanted roll during high g manoeuvres".

Page on Applebay Zuni and Zuni 2 sailplanes from on-line tour of National Air and Space Museum Garber facility

Wikipedia entry on Aerianne Swift foot-launchable ultralight sailplane

Webpage for Aerianne company (navigate to "Swift Aircrafts")

"Hang Gliding Wings Bible" entry for Bright Star Millenium foot-launchable ultralight sailplane

Webpage for Ruppert Archaeopteryx foot-launchable ultralight sailplane

Wikipedia entry on the Horten brothers

Link to discussion forum (in German) on ATOS "Cage" ultralight sailplane. Some photos are included.

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  • $\begingroup$ It would be interesting to know why the sidestick controller used in the F-16 does not cause "unwanted roll during high g manoeuvres", and whether or not it would be practical to adopt the same ergonomics to a sailplane. Perhaps a sailplane cockpit does not have room for an armrest that is used in the F-16 to stabilize the pilot's forearm? $\endgroup$
    – quiet flyer
    Dec 25, 2022 at 22:34
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    $\begingroup$ Well, first, determine what it was about the Zuni sidestick that did cause / induce / contribute to an increased risk of those unwanted roll inputs. I'd suspect that the long travel necessary for a mechanical connection to the elevator makes an armrest more problematic, since the forearm isn't in a single position. The F-16's sidestick, by contrast, is a computer input, and has nearly zero travel, meaning that the forearm doesn't appreciably move and can remain consistently supported in all regimes. $\endgroup$
    – Ralph J ♦
    Dec 26, 2022 at 4:41
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Ironic for me to come across this question. I own an HP-18 glider and yes it has a side stick control. The Diana 2 glider also has a side stick. I have researched and have yet not come across any other gliders with a side stick. . Perhaps a few things to say about the HP-18. I bought my glider with a centre stick conversion kit and I had intended to install the centre stick. I found that I also wanted to adjust the instrument panel and bring it closer to me (the instrument panel is located below my knees and I sit almost lieing down so I can't reach the instrument panel). The centre stick conversion kit would prohibit me from moving the panel closer. So I decided not to install the centre stick conversion. . The HP-18's side stick handle is actually located higher than your shoulder meaning the angle from your elbow to your hand is upward implying your blood has to travel upward towards your hand - this will become tiring. . I was inspired by the Diana 2 glider that has the control stick at your waist. This is far more ergonomic. . I found that I was able to move the HP-18 control stick to my waist area - the glider is actually wide enough to give me comfortable space with the stick alongside. I did have to modify and decrease the 'aileron travel' meaning slight movements of my hand from left to right will result in large aileron movements. The elevator movement is still heavy though. I have checked and double checked that my conversion has nothing to do with the heavy elevator. I am convinced that the HP-18 V-tale is the reason for such a heavy elevator. . So far my conversion feels really cool - I hope I don't kill myself flying this glider.

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  • $\begingroup$ Welcome to Aviation SE. Is it possible to include a photo of the cockpit layout, this may give more context both to your answer and in fact the question itself? $\endgroup$
    – GremlinWranger
    Jan 5 at 22:37
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The Waco CG-4 first flew in 1942 and was selected to be the standard USAAF assault glider.

It had a steering wheel.
Does that count? enter image description here

Picture credit: flight-manuals-online.com

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    $\begingroup$ The question does exclude cargo gliders, certainly different space constraints here than a sport glider! $\endgroup$
    – GremlinWranger
    Dec 25, 2022 at 22:40
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    $\begingroup$ Sorry, cargo gliders not welcome... $\endgroup$
    – Sanchises
    Dec 26, 2022 at 6:36

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