Wing Drop, Aerotow vs Winch, Grass vs Pavement.

"What else did I miss?"---the other side of the equation in risk analysis.
What is the worst that can happen if I don't release? vs What is the worst that can happen if I do?
There may be a 1-2 second "startle factor" in some cases. So, the decision must be pre-loaded.
There is very little cost (usually) to a release.


On Saturday, March 20, 2021 at 8:41:52 AM UTC-4, Eric Greenwell wrote:
Brian wrote on 3/19/2021 8:41 PM:
... Do you feel lucky???

So back to my risk assessment...IMO..

- tip wheels/skids - Skids and shorter = increased Risk
- surface drag = More Drag = Increased risk
- water ballast = Heaver wings = Increased Risk
- tug acceleration = I don't know. Once the wing drops, things will happen slower with a low power tug, a high power tug seems like it has more prop wash to cause the wing to drop in the 1st place and the energy in t he system is building faster, so I think I am leaning toward a High Power tug = maybe an increased risk
- hook location (no, a nose hook will not save your ass, despite proponents) CG hook = Increased risk.
- wind direction and strength = cross winds = increased risk, less headwind = increased risk.
- glider type = a consideration for sure but takes some experience to know if higher or lower risk.
- spoiler and flap setting = again likely glider dependent but I know a lot of people start with spoilers extended to prevent wing drop. would think less flap would be better. takes some experience to know.
- dumb luck - The whole point of taking a hard look at the details., How many increased risked factor might apply.

here's a couple more
Rope Length = I would think a shorter rope would = increased risk, more propwash to cause drop
Brake Capacity = poor braking capacity = increased Risk
obstructions to the side of launch area = present = increased Risk
My experience with aerotows is:

-Starting in negative flaps until about 20 knots IAS is better than using positive flaps
-Starting with spoilers extended is definitely better(especially noticed with my ASW20C)
-Using a nose hook instead of a CG hook is better with a wing runner, definitely better when
launching without a wing runner; also, much less likely to run over the rope at the very start.
(I had retrofitted my ASW20C with a nose hook, so I could try it both ways)
-Winglets are better than no winglets.\ (I noticed that because my ASH26E came without
winglets, but I retrofitted them several years later).
-A steerable tail wheel is a terrific aid: without one, you are basically ballistic until you
have 15+ knots. I suspect many of the start-of-tow accidents would be avoided if the gliders
had one. It can also be a real asset in crosswind landings, but that depends a bit on the
tailwheel design and your technique.

So, what to do:

-Every glider can use spoilers at the start, so it's worth investigating that to learn if that
will help in your glider.
-If you have flaps, find out if negative flaps help
-If you don't have a nose hook (or "forward hook" on some Schleicher gliders), see if there is
a retrofit for it.
-If you were thinking about adding winglets to your glider, you now have another reason to do it.
-Good luck finding a steerable tailwheel retrofit, but you can still nag your glider
manufacturer about it.


--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1