Why are side sticks unpopular in sailplanes

With the centre stick I fly with both hands, sometimes at
the same time, I never think about it. Gear, ballast vent on the right,
brakes, trim release on left. Center stick has to be best.


OK, here my glider/slow speed analysis... At the speeds we fly, and thus
the relatively small circle diameters, the outboard wing will be going
marginally faster than the inboard wing. This means that it creates more
lift than the inboard wing due to relative speed alone, and thus to keep
from over-banking I find the need to apply a very small amount of top
aileron (against the turn) in order to keep a stable bank angle and
equalize the lift generated by both wings. Because the outer wing goes
faster, it also generates more drag as well, so I find that I have to hold
slight bottom rudder pressure along with the top aileron in order to have
the yaw string going straight back.

So, now think about how that translates to operating the stick. With a
center stick, it is easier to make left turns and pull the stick straight
back towards your right elbow and right hip, than it is to make right
turns and be pushing the stick towards your left hip (all while using your
right hand). I have trained myself to fly with either hand so that I use
the opposite hand to the direction I am thermalling in. George Moffat and
Dick Johnson did this as well, so I am not alone. This may partially
explain why so many glider pilots prefer to make left turns (always flying
with their right hands). I also know that George and Dick initiated right
hand turns whenever they could (in order to set the turn direction of a
thermal) as a competitive trick, knowing that most of their competitors
would be less comfortable in a right hand turn than they were.

Translate this to a gimballed side stick where all motion is in the wrist,
and then I don't believe that the ergonomics will preference one turn
direction over another, but with a center stick there are good reasons to
be able or want to switch hands on the stick.

Interestingly (to me, anyway) enough, early-on I found myself preferring
left-hand circles in a (center-sticked) 1-26, which bothered me
intellectually...but upon transitioning to a (center-sticked, 15-meter)
Concept 70 I could detect no turn direction bias. Eventually I concluded my
in-turn visibility was better in the 1-26 in a left turn than in a right turn,
almost certainly due to the (somewhat poor, for 5'9" me) straight-ahead viz in
the 1-26, and it was easier to bias my whole torso to the left for best
in-turn viz than it was to the right. Doing so to the right felt somehow
"forced," perhaps due to where my right elbow ended up, somewhat scrunched
into a corner of the cockpit. For whatever reason, it never occurred to me to
try a right hand turn using my left one on the stick.

With no apparent visibility bias in the ("normal/semi-reclined" pilot
position) C70, there was no turn-direction bias...which remained the case
until I transitioned into my (side-sticked, similar-to-C70-seating position)
Zuni, when (briefly) a left-turn bias reappeared. Once my right forearm
muscles adapted to/strengthened from the grunt required to lift/horse the
(heavy in roll) stick to the right, the bias again disappeared, and - as it
should be, IMO - whichever side on which I encountered the thermal lift
dictated initial bank direction.

Having essentially zero experience in earlier-generation, long-spanned, ships
(commonly flown by Moffat and Johnson), perhaps some aspect of muscle power
bias might be a factor for some in them? In any event, these sorts of
considerations seem to me to be pretty much toward the fringe of ship-handling
attributes...real enough, but far from deal-killers to (most?) potential
purchasers. Of course, if money were no object, then I might think about "ship
quirks" differently!

Bob W.

I've always felt it was easier to push the stick to the left while
pulling it back (pitch control) than it was to pull it right while
pulling. For me it has to do with the mechanics of the wrist and elbow
joints. The more stick throw required, the more apparent it is to me
sitting on my couch and pretending to fly. It's obvious to me that,
with a long throw, a center stick is preferable, with a short throw, not
so much. I really think it comes down to preference and I can get used
to anything. In the Stemme, I take off with my left hand so I can keep
my right on the throttle. I land with my right hand so I can keep my
left on the dive brake lever. After securing the engine, I switch off
hands now and then to fiddle with an instrument (the soaring stuff is in
the middle of the panel to my right), to eat an apple, or just for a
change of pace.


On 2/23/2017 7:21 PM, Bob Whelan wrote:
With the centre stick I fly with both hands, sometimes at
the same time, I never think about it. Gear, ballast vent on the right,
brakes, trim release on left. Center stick has to be best.


OK, here my glider/slow speed analysis... At the speeds we fly, and
thus
the relatively small circle diameters, the outboard wing will be going
marginally faster than the inboard wing. This means that it creates
more
lift than the inboard wing due to relative speed alone, and thus to keep
from over-banking I find the need to apply a very small amount of top
aileron (against the turn) in order to keep a stable bank angle and
equalize the lift generated by both wings. Because the outer wing goes
faster, it also generates more drag as well, so I find that I have to
hold
slight bottom rudder pressure along with the top aileron in order to
have
the yaw string going straight back.

So, now think about how that translates to operating the stick. With a
center stick, it is easier to make left turns and pull the stick
straight
back towards your right elbow and right hip, than it is to make right
turns and be pushing the stick towards your left hip (all while using
your
right hand). I have trained myself to fly with either hand so that
I use
the opposite hand to the direction I am thermalling in. George
Moffat and
Dick Johnson did this as well, so I am not alone. This may partially
explain why so many glider pilots prefer to make left turns (always
flying
with their right hands). I also know that George and Dick initiated
right
hand turns whenever they could (in order to set the turn direction of a
thermal) as a competitive trick, knowing that most of their competitors
would be less comfortable in a right hand turn than they were.

Translate this to a gimballed side stick where all motion is in the
wrist,
and then I don't believe that the ergonomics will preference one turn
direction over another, but with a center stick there are good
reasons to
be able or want to switch hands on the stick.

Interestingly (to me, anyway) enough, early-on I found myself
preferring left-hand circles in a (center-sticked) 1-26, which
bothered me intellectually...but upon transitioning to a
(center-sticked, 15-meter) Concept 70 I could detect no turn direction
bias. Eventually I concluded my in-turn visibility was better in the
1-26 in a left turn than in a right turn, almost certainly due to the
(somewhat poor, for 5'9" me) straight-ahead viz in the 1-26, and it
was easier to bias my whole torso to the left for best in-turn viz
than it was to the right. Doing so to the right felt somehow "forced,"
perhaps due to where my right elbow ended up, somewhat scrunched into
a corner of the cockpit. For whatever reason, it never occurred to me
to try a right hand turn using my left one on the stick.

With no apparent visibility bias in the ("normal/semi-reclined" pilot
position) C70, there was no turn-direction bias...which remained the
case until I transitioned into my (side-sticked,
similar-to-C70-seating position) Zuni, when (briefly) a left-turn bias
reappeared. Once my right forearm muscles adapted to/strengthened from
the grunt required to lift/horse the (heavy in roll) stick to the
right, the bias again disappeared, and - as it should be, IMO -
whichever side on which I encountered the thermal lift dictated
initial bank direction.

Having essentially zero experience in earlier-generation,
long-spanned, ships (commonly flown by Moffat and Johnson), perhaps
some aspect of muscle power bias might be a factor for some in them?
In any event, these sorts of considerations seem to me to be pretty
much toward the fringe of ship-handling attributes...real enough, but
far from deal-killers to (most?) potential purchasers. Of course, if
money were no object, then I might think about "ship quirks" differently!

Bob W.

--
Dan, 5J