On 17 Mar, 10:00, Peter Higgs wrote:
Hi Mike, what are you towing.. *A Horsa Glider?
75 pounds x (L/D) of 40 * = * 3000 Lbs
I would think the tow rope 'Thrust' would be nearer 20-25 lbs.

We covered this a few posts back. During the two the glider's flight
path is - obviously - inclined upwards, so the lift vector is inclined
backwards, giving a horizontal component of lift for the tug to
overcome. If the glider is doing 60kt, climbing at 4kt and weighs
1000lb then this backwards lift is close to 1000 * sin (arctan (4/60))
which is 67lb.

Ian