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Why are side sticks unpopular in sailplanes



 
 
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  #1  
Old February 19th 17, 12:14 PM posted to rec.aviation.soaring
J. Nieuwenhuize
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Default Why are side sticks unpopular in sailplanes

Side sticks seem pretty popular in powered aircraft. Personally like them.
In sailplanes they have the additional advantage of allowing either a smaller cockpit (less drag) or more room. Diana, HP18 and several older designs have them.

Yet, they seem highly unpopular. Why would a well-designed sidesticks not be liked, just because it's different, or are there reasons I'm missing?
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  #2  
Old February 19th 17, 01:08 PM posted to rec.aviation.soaring
Tango Eight
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Default Why are side sticks unpopular in sailplanes

On Sunday, February 19, 2017 at 7:14:48 AM UTC-5, J. Nieuwenhuize wrote:
Side sticks seem pretty popular in powered aircraft. Personally like them.
In sailplanes they have the additional advantage of allowing either a smaller cockpit (less drag) or more room. Diana, HP18 and several older designs have them.

Yet, they seem highly unpopular. Why would a well-designed sidesticks not be liked, just because it's different, or are there reasons I'm missing?


Had a side stick for a decade. Center stick is just better. Having a fuselage big enough to pack a lunch and a sensible landout kit is a good thing, too.

Evan Ludeman / T8
  #3  
Old February 19th 17, 02:57 PM posted to rec.aviation.soaring
Martin Gregorie[_5_]
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Default Why are side sticks unpopular in sailplanes

On Sun, 19 Feb 2017 05:08:07 -0800, Tango Eight wrote:

On Sunday, February 19, 2017 at 7:14:48 AM UTC-5, J. Nieuwenhuize wrote:
Side sticks seem pretty popular in powered aircraft. Personally like
them.
In sailplanes they have the additional advantage of allowing either a
smaller cockpit (less drag) or more room. Diana, HP18 and several older
designs have them.

Yet, they seem highly unpopular. Why would a well-designed sidesticks
not be liked, just because it's different, or are there reasons I'm
missing?


Had a side stick for a decade. Center stick is just better.

Can you expand a bit, please?

I wondered if the short grip-pivot lever might raise stick forces in roll
and/or coarsen aileron control, but I've flown a DG-300, which has a
similarly short grip-pivot distance on the roll axis as well as the same
sliding pitch motion and don't recall that I found the control feel a lot
different from a centre stick.

The only thing I recall that's comment-worthy is that the DG-300's
'automatic trim' system has a more friction in it than the Libelle's
system, but that has nothing to do with side sticks.


--
[email protected] | Martin Gregorie
gregorie. | Essex, UK
org |
  #4  
Old February 19th 17, 03:33 PM posted to rec.aviation.soaring
Dan Marotta
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Default Why are side sticks unpopular in sailplanes

I've never flown one but, if the pitch control is sliding rather than
pivoting, I don't think I'd like it. I learned to fly with my wrist,
not my arm. It just seems to me that it would be more work than
relaxation. Again, I've never flown one.


On 2/19/2017 5:14 AM, J. Nieuwenhuize wrote:
Side sticks seem pretty popular in powered aircraft. Personally like them.
In sailplanes they have the additional advantage of allowing either a smaller cockpit (less drag) or more room. Diana, HP18 and several older designs have them.

Yet, they seem highly unpopular. Why would a well-designed sidesticks not be liked, just because it's different, or are there reasons I'm missing?


--
Dan, 5J
  #5  
Old February 19th 17, 03:54 PM posted to rec.aviation.soaring
Vaughn Simon[_2_]
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Default Why are side sticks unpopular in sailplanes

On 2/19/2017 7:14 AM, J. Nieuwenhuize wrote:
Why would a well-designed sidesticks not be liked,


Like others here, I've never flown with a side stick. That said, in
gliders I've probably switched hands on the control stick countless
times for more reasons than I could possibly enumerate here. I'm
thinking that would be difficult or impossible with a side stick.

Most airplanes with side sticks have auto pilots to free up the pilot's
hands for other chores, gliders don't.

Vaughn
  #6  
Old February 19th 17, 04:02 PM posted to rec.aviation.soaring
Tango Eight
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Posts: 596
Default Why are side sticks unpopular in sailplanes

On Sunday, February 19, 2017 at 9:59:27 AM UTC-5, Martin Gregorie wrote:
On Sun, 19 Feb 2017 05:08:07 -0800, Tango Eight wrote:


Had a side stick for a decade. Center stick is just better.

Can you expand a bit, please?


Sure. I think the irreducible issue is simply one of leverage and limited motion options. There's only one way to grip the stick, there's only one way to interact with it.

All of the side stick designs I've seen for direct mechanical actuation of controls require a sliding fore/aft motion for elevator (elbow + shoulder) and a rolling motion of the wrist for aileron. Blending those motions with finesse is just more work (more fatigue) than a conventional gimballed stick. I landed out a couple of times in my side stick glider simply because I got tired and sloppy after 4+ hours and couldn't climb well. Coordination never became unconscious in that ship.

The other things that I don't like about side stick equipped gliders tend to be the *reasons* designers opted for side sticks, not the sticks themselves: supine seating position, lousy forward visibility, tiny instrument pods, cockpits with no extra space for anything.

That said, I have always had a desire to fly (but not own!) a Diana2, just because the thing was so radical.

Evan Ludeman / T8
  #7  
Old February 19th 17, 04:46 PM posted to rec.aviation.soaring
Bob Whelan[_3_]
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Posts: 385
Default Why are side sticks unpopular in sailplanes

On 2/19/2017 5:14 AM, J. Nieuwenhuize wrote:
Side sticks seem pretty popular in powered aircraft. Personally like them.
In sailplanes they have the additional advantage of allowing either a
smaller cockpit (less drag) or more room. Diana, HP18 and several older
designs have them.

Yet, they seem highly unpopular. Why would a well-designed sidesticks not
be liked, just because it's different, or are there reasons I'm missing?

Occam suggests one should never overlook the power of "popular/inertial
thinking," but that noted, and based on 2000 hours in a side-stick-equipped
sailplane...

Unmitigated Pros:
- Unrestricted lap space (*I* like it!)

Double-edge swords:
- slider in pitch (not pivoting at base...quite noticeable on first flight;
strictly a conceptual difference thereafter. But given the light
elevator/all-flying-tail forces, part of me has never quit wondering how a
"pivoting implementation" in this ship woulda compared.)
- relatively high roll forces in my ship's implementation, compared to pitch
(and rudder) forces, so definitely "a different feel" from the vast majority
of sailplanes out there; not inherently dangerous, but..."quirky?"
- neutral aileron at "some angle" to the cockpit wall (i.e. not
vertical/"obvious"). After the "controls free?" part of my checklist, aileron
neutralization done by centering the stick between the limits of its lateral
throws, as distinct from centering it vertically as most pilots probably do
"without thinking." Dealing with T.O. crosswinds/gusts is as intuitively
obvious as any center stick implementation with which I'm familiar.

Kinda-sorta related, Dick Johnson noted this particular ship's "neutral stick
position" implementation had possibilities for uncommanded roll inputs under
high/low-G inputs (think rotor turbulence), but I've never found that an
issue. This may be somewhat a function of aileron forces, too...

As for pitch, normal in-flight pitch changes I find most smoothly met by how
much I curl my fingers. Though the stick has "quite a range" of pitch throw,
normal flight uses very little of it...mostly (in my experience) occasionally
on takeoff in very gusty conditions.

I've seen/helped-rig other side-stick-ships (Diamant HBV, HP-18), I don't know
whether they were "sliders" or "pivoters" in pitch, but I imagine any
side-sticker would have the beer-around-the-campfire "pitch/roll funkiness"
available for opinionating.

As a natural right-hander, I've often imagined adapting to a left-side stick
(think many powerplanes) would require far more "mental adaptation" on my part
than did adapting to my Zuni's right-side-stick. Maybe some Airbus-driving
glider pilots will chime in?

FWIW, I transitioned into my side-sticker with 400 total hours and zero
outside checkout advice, and quit thinking about it "being different" within
two or three flights. Over the years for that matter, it's never been much of
conversation starter in BS sessions...though I suppose that option is always
there depending upon one's personality.

Bob W.
  #8  
Old February 19th 17, 05:24 PM posted to rec.aviation.soaring
Bob Whelan[_3_]
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Posts: 385
Default Why are side sticks unpopular in sailplanes

On 2/19/2017 9:02 AM, Tango Eight wrote:
On Sunday, February 19, 2017 at 9:59:27 AM UTC-5, Martin Gregorie wrote:
On Sun, 19 Feb 2017 05:08:07 -0800, Tango Eight wrote:


Had a side stick for a decade. Center stick is just better.

Can you expand a bit, please?


Sure...

(Snip...)

All of the side stick designs I've seen for direct mechanical actuation of
controls require a sliding fore/aft motion for elevator (elbow + shoulder)
and a rolling motion of the wrist for aileron. Blending those motions with
finesse is just more work (more fatigue) than a conventional gimballed
stick. I landed out a couple of times in my side stick glider simply
because I got tired and sloppy after 4+ hours and couldn't climb well.
Coordination never became unconscious in that ship.


"Mercy!" he exclaims about having to landout. I never suffered that particular
fate as a result of my side stick (longest single-flight time 9 hours), but I
concur with the sentiment of that last sentence. Coordinating my Zuni is
another of those things that's "different" about the ship...as was
coordinating my (similarly high-in-roll w. light pitch forces) HP-14 before
it. Not dangerous or difficult, just "not unconscious," as in always on the
fringes of my awareness. But, from my perspective, simultaneously never a
problem, just "different."

FWIW - for readers unfamiliar with the HP-14, HP-18, Zuni designs - Evan's
HP-18 (side stick) and my HP-14 (center stick) are both fully supine designs,
while the (original side-stick-design) Zuni has a "standard semi-reclined"
seating position...with a normally-sized cockpit and instrument pod and view
outside.

I transitioned into my HP-14 with ~200 total hours and put ~200 hours on it
before transitioning into the Zuni. No "German quality" optics on either, the
HP-14 having more distortion thanks to looking though its flat-wrapped forward
canopy section at very shallow in-flight angles. I always found that more of a
"mental nuisance" than I did anything about the fully-reclined seating (*very*
comfortable IMO). Ditto its quite narrow - even for thin, small-framed me -
cockpit with limited sandwich space...though it had eNORmous space atop/after
the spars for water (sucked via tube), multiple O2 tanks, a tent (aerotowed to
a camp once), etc. Of course all visual complaints vanished upon use of
landing flaps (I always used 90-degrees in the HP). So its supine pilot
position may well have been somewhat problematic for old-style,
visually-acquired turnpoints, in contest flying when the HP-14 was designed...

Bob W.
  #9  
Old February 19th 17, 06:08 PM posted to rec.aviation.soaring
Tango Eight
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Posts: 596
Default Why are side sticks unpopular in sailplanes

It's probably worth adding that there were a number of factors that made the HP-18 a lot of work to fly well, among them irreducible play in the stick aileron motion, no aileron differential(!!), small tail volume, no hands off stability at all. It wasn't really my intention to blame the wear out factor on the stick location, but it probably came out that way.

-Evan
  #10  
Old February 19th 17, 06:21 PM posted to rec.aviation.soaring
Michael Opitz
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Posts: 218
Default Why are side sticks unpopular in sailplanes


As a natural right-hander, I've often imagined adapting to a left-

side
stick
(think many powerplanes) would require far more "mental

adaptation" on my
part
than did adapting to my Zuni's right-side-stick. Maybe some

Airbus-driving glider pilots will chime in?

I have about 3500 hours in the left seat of the A-319/320. It
turned out to be no big deal with a the stick in my left hand. I also
have time in the F-16 with a right side stick. Both aircraft's sticks
are mounted vertically, so the neutral position is in the center. The
biggest issue I had was that both aircraft are "fly by wire", which
means that the stick inputs which you make go to a computer as
electrical signals, and then the computer ("HAL" in the F-16, and
"FIFI" in the A 320) gets to decide what you are trying to get the
aircraft to do, and then sends the signals on to the flight control
power units. Sometimes, things get interpreted as in a normal
aircraft, but there are occasions where one has to make somewhat
un-natural control inputs in order to get the computer to get the
aircraft to do what you want it to do....(a whole other off-topic
story)

I like flying with a side stick. It feels natural. On the Airbus, it
allows room to have a tray table for approach plates (if you don't yet
have an electronic cockpit) and meals, etc instead of having a yoke
in the way.

On the down-side, it is hard to reach across the cockpit to fly with
the other hand in case one needs to do so. Think taking a combat
hit to one arm, or other more mundane chores. A center stick
makes flying with either hand much easier.....

RO


 




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