Let's talk ground launching........

Rusty wrote:
Hello Again:
Thank you all for the response, it is all very welcome. I do live in
South Texas and we have access to a basically un-used well kept
200'x6000' hard packed grass field. We have recently picked up an
older winch that needs a litte TCL but with a little work will be very
usable. We are also setting up for straight auto-tow and are in the
process of building pulleys for reverse pulley. One of the many
questions I have is this: is a parachute necessary on straight auto-tow
and if so how far from the glider should the parachute be located?
Many more questions later.
Thanks
Rusty

We did straight autotows for several years with a product known as
parafil. If there's a similar product, it might be a good option for
some. Some prior postings.

http://tinyurl.com/7em69

Frank

On Fri, 02 Sep 2005 13:35:49 +0000, Chris Nicholas wrote:

I'm not from Dunstable but.....

I think items 7 and 10 should be swapped so the weak link is part of the
wire strop assembly and item 4 should be selected so its colour matches
the colour of the weak link.

No doubt someone from Dunstable will correct the following if I got it
wrong or it has changed, but my notes of their assembly were as follows,
starting at the glider end:

1. Tost rings

2. wire rope a few feet long.

3. ferrule to secure end of 2 into a loop.

4. plastic hose over 2.

5. ferrule to secure other end of 2 into a loop.

6. oval link with flat section on one side.

7. quick-release hook mating with 6.

8. shackle.

9. weak link assembly.

10. shackle.

11. shock rope about 80 feet long.

12. shackle.

13. triangular ring on end of drogue.

14. drogue.

15. metal end fitting on drogue.

16. shackle.

17. plate on shackle to take the wear.

18. swivel.

19. shackle.

20. oval link with flat section on one side.

21. quick-release hook mating with 20.

22. loop of main winch cable.

23. first ferrule securing 22.

24. plate on loop to take the wear.

25. second ferrule securing 22 and 24.

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

I said a winch operation wouldn't mix well with airliner. Well, it can
be done, as this picture demonstrates:
http://www.dg-flugzeugbau.de/foto-05-09.html

However it must be said that this aren't scheduled but mostly private
jets (yes, private, not business!) and that the airport is a major
gliding center, so everybody is very willing to cooperate.

Stefan

Stefan wrote:
GM wrote:

Many folks in the club I recently left in NE Ohio where dead set
against any kind of ground launching for they had heard how dangerous

Frankly, winch launching *is* dangerous if don't have the required
knowledge and aren't dead serious about it. But that's nothing new in
aviation.

it is and that you can not soar away out of a winch launch.

This depends on your location.

If you think of introducing winch operation at your site, then I suggest
you take the following steps.

1. Answer the following questions: How long will the cable be? How much
height can be achieved with this cable lenghth? Is this enough to get
away? (Always, sometimes, rarely).

2. Is a winch operation feasable at your site at all? (It mixes poorely
with scheduled Airliers.)

3. Calculate the cost.

4. Two or three pilots go somewhere where they have a winch operation.
Try it. Talk to them.

5. Best would be if you could hire a winch for a weekend at your place.
Together with the winch operator, of course, and a flight instructor.
Maybe obsolete if step 4 includes enough pilots.

6. Based on that experience, decide.

7. Most important: If you decide pro winch, get proper istruction, or
you *will* have fatalities. (Not panicking, I love winch launches. But
they *are* serious.)

Stefan
(previously posted under another thread)

http://members.tripod.com/~thrift/soaring/psa2.html

2000ft launches
BLM land access
non-profit (social)
Located several miles from local airport according to map.


Frank Whiteley
p.s. cool animation

Martin Gregorie wrote [snip] " . . .I think items 7 and 10 should be
swapped so the weak link is part of the wire strop assembly and item 4
should be selected so its colour matches the colour of the weak link."

Some clubs, including mine, do that - change the strop with weak link
attached, to suit the glider. Some have several weak links on the cable
and just switch the same strop from one to another. Some may just change
the weak link, with quick releases either side, so only one strop is
needed.

Chris N.






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Scary thought that. I have a total of three aero tow launches representing less
than 1% of my flying yet somehow have managed to thermal away many times. In
fact well enough that my average flight time is 33 minutes. Considering I do a
fair amount of intro flights of 5 to 10 minutes that is not a bad average for a
launch type that is so difficult.

One thing we notice at our club, by the time we send someone solo, they can find
thermals and get away pretty efficiently. Nothing like being 1,500" AGL to focus
the mind on finding lift...

Maybe we are just spoiled with good conditions.

GM wrote:
Frank Whiteley wrote:

Rusty wrote:

Hello All:
With the price of fuel going up and the price of AeroTows close behind
it I think the need to follow the lead of our brethren in the UK is
close at hand. I have heard talk of the infamous $100.00 tow and know
that I for one can't afford it, I have to work for a living as do most
of you! I and some of my fellow pilots are wanting to start a new club
and are want to use winch, auto tows and reverse pulley launching
exclusively. Let's discuss the different aspects of ground launching as
the only thing that will save our sport and make it inviting once again
to new students.
Thanks
Rusty

http://groups.yahoo.com/group/winchdesign/
Many of the issues are discuseed here and there are some archival
files/images to review. I'm quite happy to carry on here or in the
group.

There are a few stumbling blocks to ground launching, but most can be
overcome. Space is definitely one. If your launch rope can span
4000ft or more, it's very attractive. Others have done with less
distance. Location helps. Thinking outside the box helps also.

So, where are you? Appears you may be in Texas. That could be
fortunate as there are some ground launch activities there, in case
pilot and instructor qualifications are needed. If you are seriously
considering starting a club in the US, have a look here
http://www.soarcsa.org/ssa/clubs/2005_start_here.htm

Frank Whiteley
SSA Clubs & Chapters Committee member
CSA Winchmeister



.... Thinking outside the box helps also....

Frank, well said!
Many folks in the club I recently left in NE Ohio where dead set
against any kind of ground launching for they had heard how dangerous
it is and that you can not soar away out of a winch launch. Most of the
nay-sayers had never ground launched nor had they seen a modern winch
in action.
I think the main obstacle for introducing winch- or ground launching in
the US is to change the perception of what a modern winch is capable of
and at what cost at that.

'Folks - It ain't your daddy's Gehrlein winch anymore!!'

Anybody interested feel free to read up on that issue at (or join)
http://groups.yahoo.com/group/winchdesign/ .

I think we have collected the most comprehensive set of information
regarding winch launching in the last year and a half from practical
'how to' knowledge to all sorts of theoretical papers on the physics of
a winch launch.
Lets get to work!

Uli Neumann



--
Bruce Greeff
Std Cirrus #57
I'm no-T at the address above.

On Fri, 02 Sep 2005 21:56:11 +0000, Chris Nicholas wrote:

Martin Gregorie wrote [snip] " . . .I think items 7 and 10 should be
swapped so the weak link is part of the wire strop assembly and item 4
should be selected so its colour matches the colour of the weak link."

Some clubs, including mine, do that - change the strop with weak link
attached, to suit the glider. Some have several weak links on the cable
and just switch the same strop from one to another. Some may just change
the weak link, with quick releases either side, so only one strop is
needed.

Chris N.

Apologies, Chris. I thought that you'd gotten confused with all the
shackles - the sort of thing I'd do.

The only club I've visited that swapped the weak link but not the strop
was Auckland, NZ - and they use a really long strop, at least 5 m, and
aero-tow rope in place of steel cable on the winch.

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

On Fri, 2 Sep 2005 10:15:14 UTC, Chris Nicholas
wrote:

: For reverse pulley, I would look at the Cotswold type but incorporate a
: flat part of the "pulley" with an anvil in line with the pivot, like the
: Essex set up. The spring loaded chisel would go through the hollow pivot
: shaft.

Who operates the guillotine in these systems? Do you need someone
stationed by the pulley, or is there some sort of remote actuation?

Personally, I think it's time we stopped messing about with spring
loaded cutters and went to explosive ones, but that's incidental here!

Ian

Ian Johnston wrote:[snip]Who operates the guillotine in these systems?
Do you need someone stationed by the pulley, or is there some sort of
remote actuation? [snip]

The pulley was mounted on the back of a large, heavy truck, chocked to
stop the forces dragging it down the runway. The guillotine control was
a knob in the back of the cab (seat reversed on the passenger side IIRC)
which released the spring loaded chisel if required. We always had a
chopper person there during launching as a safety precaution, and they
had to be in the cab because of the danger of thrashing wire after a
break or chop.

They also served to speed up the launching process, by gathering the
drogue and strop etc. to hook onto the tow truck when it drove up.

For fastest turnaround, two tow trucks are used. One does the launch,
carries on to the launch point after glider release and delivers that
end to the next glider. The other follows the launched glider up the
runway, passes the launching truck half way, and arrives at the pulley
in time for the chopper person to hook on. The cable is double ended, of
course, with drogues and rings etc. at both ends. An extra ring on the
main cable goes to the tow truck Tost release, so no wear and tear on
the drogue etc. at that end when launching. At its best, it gives
similar turnaround to the Long Mynd's cable retrieve winch system - 20
or more launches per hour.

It is only worth doing all this if you need a lot of launches. Straight
autotow is quicker and cheaper to establish, needs less training and
manpower to operate, but is a bit harder to get a quick turnaround. You
can use two tow trucks to speed it up, if you have a wide runway - one
retrieves the cable it has launched with and returns to the launch
point, while the other does the next launch. Safety precautions need
some care with this - we did it in the 1970's when there were fewer
legal cases likely in the event of nasty incidents.

Chris N.






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Ian Johnston wrote:
On Fri, 2 Sep 2005 10:15:14 UTC, Chris Nicholas
wrote:

: For reverse pulley, I would look at the Cotswold type but incorporate a
: flat part of the "pulley" with an anvil in line with the pivot, like the
: Essex set up. The spring loaded chisel would go through the hollow pivot
: shaft.

Who operates the guillotine in these systems? Do you need someone
stationed by the pulley, or is there some sort of remote actuation?

Personally, I think it's time we stopped messing about with spring
loaded cutters and went to explosive ones, but that's incidental here!

Ian
The Cotswold Reverse Pulley had no guillotine and the reasoning was
that none was needed. The design was such that the tow vehicle end
would release if there was a release failure and the glider would pull
wire and tackle back through the pulley, as needed. IIRC, there were
two release failures in the 30 years of operation and that both
recovered okay.

Frank Whiteley