adding speed/vario switch into ASW-19 control stick grip

On Thu, 20 Dec 2012 05:34:12 -0800, Bastoune wrote:

I have a LX V7 variothat has that functionality. The
automatic switching of the STF is currently based on a GPS input
(straight flight = STF, turn = vario). I am moderatly happy with the
automating switching based on that logic. Is there a better one? I
understand that the vario could also switch to SFT above a certain speed
(e.g. 60kts) but I find myself flying at best L/D at times. In that
case, the vario would automatically revert to "Vario". What "automatic
switching logic" works best in your experience?

I have an SDI C4 vario that offers the choice of manual, speed and turn
switching. The older C3 allowed you to choose speed or turn and override
it (the manual switch had a three position switch: climb-auto-cruise but
the C4 omitted the manual override. I tried circling and hated it and now
use speed switching. This instrument allows different speeds to be set
for cruise-climb and climb-cruise which is useful: I like climb-cruise
set 5-6 kts faster than cruise-climb and would probably hate a vario
that had only one switching speed, but ymmv.

If you try speed switching, be prepared to spend time tuning it to the
way you like to fly the glider its in: using the same instrument in two
fairly different gliders showed me that you need to tweak both the
switching speeds to suit both the glider and your flying style, but get
it set right and it is almost always in the mode you want.

A reasonable start point is with cruise-climb set about 2-3 kts below
best glide speed and climb-cruise set around 5 kts above best glide.
Then go fly and adjust as needed. What you want is for it to stay in
cruise along a weakish street but not suddenly jump out of climb while
you're thermalling.



--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

Since I make installation into a club glider, I just want it to be identical with other two with XC potential. LX160 has SC/vario/auto switch, so the pilot can make his own choice. So, I would like to install a new grip with SC/vario switch. I do not want to pay for carbon fiber, I just hope I can find something practical and proven.

I installed a bycicle grip with a CNC end cap. The lifting end cap allow fairly easy installation of the ptt button and vario switch:
"Ragley Skinny Lock On Grip"

An alternative is reusing a ski pole grips. Those are the ones usually installed by the manufacturer. Leki has some nice ones and in ski resorts you can get them free because there are plenty of broken ski poles at every rental place. Installing button and switch is often not easy because you need to do it through the hole at the back for the latch. Get the smallest button and switch you can find!

Schempp-Hirth sells a foam grip with lifting cap, as installed in new SH sailplanes. Probably the easiest solution, but not the cheapest and I'm not a friend of foam grips.

Incase your stick diameter is too small you can use heat shrink tubing with glue to widen the diameter a bit.

I would definitely recommend a switch versus automatic switching. You need a good vario reading before the thermal kicks in and an automatic switch is usually to slow especially since most speed switches have a short delay even if the set speed has been reached.

Thank you Alexander. The ski pole grip might be a good idea, I will look what is available locally. I think some DH bike grips might also be interesting. However, I still would appreciate a ready-made, tested and robust solution.

If your vario has cruise, climb, and auto functions, and you plan to install
a switch in the stick grip, I would recommend a three position switch. My
partner and I did this on our LS-6 about 20 years ago and it worked just
fine.

Forward for cruise,
Back for climb,
Middle for auto mode


wrote in message
...
Thank you Alexander. The ski pole grip might be a good idea, I will look
what is available locally. I think some DH bike grips might also be
interesting. However, I still would appreciate a ready-made, tested and
robust solution.