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Subject:   How much does the cable weigh?
Name:   JMW
Date Posted:   Sep 5, 07 - 1:11 PM
Message:   From the IEEE report:
"For low altitude flight, around 1500 ft (< 500 m), the assumption of a straight, mass-less tether is reasonable.
However, for higher altitudes, the analysis has been extended to included tether mass and tether air-loads. Roberts and Blackler and Roberts and Shepard have shown that higher altitudes are achievable using an aluminium-Kevlar composite or an aluminum-Spectra composite for the electro-mechanical tethering cable."
and:
"The electro-mechanical tether is designed to transmit 240kW at a voltage of 15kV. The electrical transmission efficiency is 90%. The tether has two insulated aluminum conductors embedded in a Vectran fiber composite. The tether’s specific weight is around 115 kg/km at a diameter of 10mm. A sample has been constructed."
OK, that's 4.6km of cable at 115kg/km which is 529kg.
Well, they base this on 10mm cable diameter. One hopes that that is the necessary cable for the tether and not simply an example.
I suppose I should now investigate the references and try and determine just how feasible they suggest the electromechanical tether would be. However, I note that they say "a sample has been constructed" which tends to suggest their is no off the shelf product with a history of similar use that we can rely upon as a guide and one wonders if they have taken into consideration our bending authors concerns and how they would answer them.
Replies:    
Re: How much does the cable weigh? by pogo · Sep 5, 07 - 5:59 PM
Re: Re: How much does the cable weigh? by Colin · Sep 6, 07 - 3:33 PM
Re: Something in the air... by John Brignell · Sep 6, 07 - 9:59 PM
Re: Something in the air... by John Brignell · Sep 7, 07 - 9:19 AM
Re: Re: Something in the air... by JMW · Sep 7, 07 - 9:49 AM
Re: Re: Re: Something in the air... by Grant · Sep 7, 07 - 1:37 PM


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