On Wednesday, January 2, 2019 at 2:11:23 AM UTC-7, Frank Whiteley wrote:
On Tuesday, January 1, 2019 at 8:13:46 AM UTC-7, Martin Gregorie wrote:
On Mon, 31 Dec 2018 19:21:45 -0800, WB wrote:

There is nothing new under the sun when it comes to ground launching,
auto tow, winch, whatever. It's pretty much all been tried. Derek Piggot
wrote a book that is a great resource for learning about ground launch
in it's many forms. Unfortunately, it appears to be out of print.

ITYM "Gliding - A handbook on Soaring Flight"

Edition 7, which I have (blue cover showing a DG-800B with its motor
out), has two chapters on ground launching and is currently on offer from
Amazon for $3.60. His books may be out of print, but you can easily find
copies. Amazon even has a Derek Piggott author page.


--
Martin | martin at
Gregorie | gregorie dot org

Derek's insights on ground launching are very good. There are a number of variables that need some additional consideration. Here in Colorado summers, we can have density altitudes approaching 10,000ft at 5500MSL field elevation, which affect performance of both winches and gliders and auto tows, if used. The OP's location is at 3000MSL with slightly lower expected seasonal temperatures.

I'm not aware of any operations that have used direct or reverse-pulleys with UHMWPE ropes. 30 plus years ago, the old Enstone GC attempted to use a pulley with Parafil and the results were not successful. Could have been a design issue. Parafil worked a treat for auto tow and could be retrieved quickly for the next launch. I'm not certain UHMWPE ropes would work in those cases, however, Amsteel II is a sheathed rope, so might work in a similar role.

Direct pulley and auto tow is often done without a drogue chute so the rope will drop without much drift. A chute could result in considerable drift without any control. A drogue chute on a reverse pulley allows the end of the rope to be landed next to the pulley and it will be set up for the next launch. A rope break is the only real problem. The OP's airport has runway lights, which in my opinion makes direct pulley and auto tow not viable. There is a second airport option, very close to the mountains, which might allow easy access to ridge soaring. If the wind is enough for ridge flight, it would also maybe help with the launch heights to reach for the lift and/or return to the airport. A reverse pulley would allow for operations from both sites, though there is the problem of different run lengths. John, what was that second airport?

Frank Whiteley

The second airport is St Ignatius (52S). Elevation is about the same at about 3K ft. Runway is only 2600 ft though. It also has runway lights.

Again, the purpose of this thread is to look at (cheap) options to get a club STARTED in a rural area in a low population density state. There is not a lot of money around here. Obviously there are better ways to launch gliders, but it costs more, and I'm looking for ways to make this affordable, at least until we can achieve critical mass to make this club self-sustaining. At that point we could start looking at options to improve launch equipment. At this point we don't even have sufficient interest to generate enough capital to buy a two-seater glider, even one that is only $6000. There is interest, but not enough people to put money on the table yet. That's my challenge.