Almost perfect payout winch launch.

On Friday, May 10, 2013 7:21:55 AM UTC-6, wrote:
I just don't see the need for winching to 2-3k feet in a glider and if you disagree you probably have some thermaling to learn.

Herb

Depends on the purpose of the flight. Early morning or late evening student training flights can benefit from higher launches.

Don is right in thinking that there should be one person in charge of the
launch.

Unfortunately the person he thinks should be in charge is at the wrong end
of the cable.

With high powered winches driving through auto transmission (Skylaunch) the
pilot has little control over the speed of launch, he just has to accept
what the winch driver gives him.

With a launch system that provides cable tension, by whatever control
system
is used, the speed is under control of the pilot. Ease off on the stick
speed increases, ease back speed reduces, just like in normal flight.

I've launched on both in the UK & I know which I prefer

PF

At 13:52 10 May 2013, Bill D wrote:
On Friday, May 10, 2013 7:21:55 AM UTC-6, wrote:
I just don't see the need for winching to 2-3k feet in a glider and if
you disagree you probably have some thermaling to learn.

Herb

Depends on the purpose of the flight. Early morning or late evening
student training flights can benefit from higher launches.

On Friday, May 10, 2013 8:42:39 AM UTC-6, Peter F wrote:
Don is right in thinking that there should be one person in charge of the launch.

Unfortunately the person he thinks should be in charge is at the wrong end of the cable.

You are correct, it's much better to have the pilot control airspeed with pitch. However, for this to happen, the winch has to control rope tension accurately as a percentage of glider weight. Control is divided where pilot controls airspeed and winch controls tension. This means Gary is right to control rope tension with his payout winch.

At 14:55 10 May 2013, Bill D wrote:
On Friday, May 10, 2013 8:42:39 AM UTC-6, Peter F wrote:
Don is right in thinking that there should be one person in charge of
the=
launch.

Unfortunately the person he thinks should be in charge is at the wrong
en=
d of the cable.

You are correct, it's much better to have the pilot control airspeed with
p=
itch. However, for this to happen, the winch has to control rope tension
a=
ccurately as a percentage of glider weight. Control is divided where
pilot=
controls airspeed and winch controls tension. This means Gary is right
to=
control rope tension with his payout winch.

No, I said there should be one person with total control of the winch, just
the same as the number of people in command of a glider. Would you fly an
airplane where one pilot had control of the stick pulling back and another
pilot was in control of pushing it forwards? The person in charge of the
launch is always the pilot of the glider who has absolute control of the
airspeed at all times via the stick and yellow knob.

From a 2500' run we get 1000 ft winch launches in still air. We are cleared
and capable of winching to 3000ft but seldom do, using a standard Skylaunch
winch.
Average winch launch at our site using the standard runs is 1500ft.

On Friday, May 10, 2013 9:36:02 AM UTC-6, Don Johnstone wrote:
At 14:55 10 May 2013, Bill D wrote:

On Friday, May 10, 2013 8:42:39 AM UTC-6, Peter F wrote:

Don is right in thinking that there should be one person in charge of

the=

launch.



Unfortunately the person he thinks should be in charge is at the wrong

en=

d of the cable.



You are correct, it's much better to have the pilot control airspeed with

p=

itch. However, for this to happen, the winch has to control rope tension

a=

ccurately as a percentage of glider weight. Control is divided where

pilot=

controls airspeed and winch controls tension. This means Gary is right

to=

control rope tension with his payout winch.



No, I said there should be one person with total control of the winch, just

the same as the number of people in command of a glider. Would you fly an

airplane where one pilot had control of the stick pulling back and another

pilot was in control of pushing it forwards? The person in charge of the

launch is always the pilot of the glider who has absolute control of the

airspeed at all times via the stick and yellow knob.



From a 2500' run we get 1000 ft winch launches in still air. We are cleared

and capable of winching to 3000ft but seldom do, using a standard Skylaunch

winch.

Average winch launch at our site using the standard runs is 1500ft.


That's a fuzzy analogy. A better analogy is an airplane with a flight engineer controlling the power of the engines. The engineer (think winch operator) applies whatever power the pilot asks for. The pilot then takes that power and controls airspeed with pitch attitude.

Please describe to us a winch accident that would be the fault of the winch and not the pilot.

Boggs

On Friday, May 10, 2013 10:25:24 AM UTC-6, Waveguru wrote:
Please describe to us a winch accident that would be the fault of the winch and not the pilot.



Boggs

First, Gary, let me say again I agree with your position on pilot responsibility and I would be perfectly willing to take a tow behind your payout winch. However, here's a couple of scenarios where a powerful winch can be safer than auto tow.

On a calm but strongly thermic day, a tailwind gust is encountered just as the glider begins rotation into the climb. If the winch has substantial reserve power, and is controlling rope tension, it will instantly add power to help the glider maintain a safe margin over stall in the critical rotation phase. In this case, the pilot has less control over his fate than the winch. If the winch or tow car power is marginal, the glider may stall in this situation.

This is why the DAeC Technical Committee guidelines set minimum power and rope speed requirements.

Another scenario is a winch which balks just after the glider is airborne leaving the glider momentarily gliding at minimum controllable airspeed. The winch then "catches" and applies full power. Without the runway surface supporting the tail wheel, and if the glider's CG is well above its hook, the inertial couple effect may cause a dangerous uncommanded pitch-up.

This is why the DAeC Technical Committee, in another paragraph, requires absolute smoothness in winch power without any tension oscillations or spikes in rope tension.