What a fascinating instruction movie. It shows that necessity is the mother of inventions!
What I do not understand however, is how the shock of the sudden load due to the build up of zero speed to 130 miles on the glider is gradually applied, so that the airframe is not pulled apart by the increase of impulsl. Is it all in the elasticity of the nylon rope?
I remember that when needing to tow a car to the garage in the sixties (when cars still could stall and stop driving), we used a tow rope on the tug car, a pair of old bycycle tires tied to the other end, and then a rope attached to the stalled car tied to the other end of the bycle tyre. The resulting ovalisation of the tyres was the needed elastics to put a gradual speed built-up on the towed car and dampen the shocks of pulling.
So how was this achieved in the case of glider towing? Can any body shed light on this?