Specs for tow rope used to tow Hamilcar gliders?

Hi Aeronut, Sorry, my error, it was circ. not diameter. I understand that ‘circumferences’ are still how ropes are measured today. We were checking the current ratings for nylon ropes of the sizes stated and it is in the 30,000lb range, whereas the I calculated that the 200cwt would have been around 22,000lbs, I guess they have developed the nylon strands to a higher level. We are now searching through the Naval arm of the service for a suitable length of 4 1/4″ circ. piece of rope and hopefully someone to splice a terminal loop into it for us.(The original info we received from a vet. was the rope was 4 1/2″ diameter! The number was close except it was circ., not dia.)
Thanks for your help.
Deryck

Deryck, I was quoting from the report and the dimensions were expressed as Circumferences (a bit odd these days), for diameters you need to divide by Pi. Therefore a 4 1/4 circumference is only 1.353 inches in diameter, which is far more realistic. Apologies for the maths lecture.
Ropes were indeed spliced and whip corded (bound). Indeed in the early days AFEE had a sailor as part of the establishment to do the splicing.

Hi Bazv, I learned on the winch but we eventually had to switch to airtow as the winch took up too much real estate and the cable seemed to find all the telephone and power lines in the area. I eventually became an instructor and then the CFI hence the large number of flights. Lots of fun sitting there and watching students get them selves in trouble!

Thanks Aeronut, that is far more info than we have been able to obtain. We had heard that the rope was 4 1/2 in diameter, but the tug end release fitting, shown in the Airborne Forces Manual, does not seem capable of being able to get a rope of that dia through it, 3 5/8 maybe, but 4 1/4 very doubtful. A 300 foot long 4 1/4 dia rope could be a serious weapon when dropped! Any info on how the rope was terminated on the release fitting, spliced?

Having written the above comment I’ve delved into my archive and found a copy of the Airborne Forces Experimental Establishment Repot E13 dated 18 August 1947 entitled Interim report on an investigation of tye suitability of Nylon for use in glider tow cables.

The report gives the following information. Nylon tow ropes for Horsa II were 2 7/8 inch circumference and 145 cwt breaking strength. Hamilcar I nylon tow ropes were 3 1/2 inch circumference and 200 cwt breaking strength. Hamilcar X nylon tow ropes were 3 5/8 inch circumference and 240 cwt.

The ‘standard’ hemp ropes were 3 3/8 inch circumference, 120 cwt for Horsa II and 4 1/4 inch, 200 cwt for Hamilcar I.

There is a short length of the tow rope used to tow the Waco Hadrian ‘Voo Doo’ across the Atlantic on display in the Museum at Middle Wallop – Its 1 inch diameter and Nylon.

Hope this helps.

I remember going through this exercise with little success, with Mr Charles Day, after I met him at Middle Wallop, he tested gliders in the US during WW2 and has since written the book ‘The Silent Ones’.
Tow ropes were Hemp or Nylon with the Hemp ones being larger in diameter (without proof I won’t state the sizes).
Nylon is more elastic and as you say can make things interesting but its elasticity is also its strength in that it absorbs shocks that would snap a hemp rope.
The Snatch launch recoveries of Waco and Horsa gliders relied in part on this elasticity along with a slipping clutch (think fishing reel) on the winch within the towing aircarft (Dakota) to take the glider from stationary to flying within a few seconds.

Hi Deryck
According to www.silentwingsmuseum.com the Hamilcar towrope was
2 inch Dia Hemp or Manila Rope.
The US would appear to have used Nylon for their Gliders and I wonder if us Brits got hold of any nylon rope before the end of the war,it would certainly absorb shock loadings better and be easier to maintain.

Hope that helps-i have done a fair bit of gliding myself but probably 95% winch launch the rest aerotow plus a few car(auto,motor)tows as well.