Space Elevator

"pacplyer" wrote in message
om...
snippage
So we wouldn't shed the 200 ft swing wing glider "diamond" till the
last second before we start slingshot-ing; since it's kiting almost
*ALL*? the weight of the near vertical portion of the line? Right?
And is the line drag number split between the two ships?

I think the joined wing would have a redline, and as you approached this,
you'd have to release and fire the rocket (or the reverse). The towed
aircraft can control its airspeed somewhat by turning nearer (slow down) or
away from (speed up) the towplane.

The 747 has to handle all the drag because it has all the power. That
includes the drag of the towed vehicle.

The towed vehicle has to handle the weight of the towline, because it and
the towline are above the 747, and it's really hard to push with a rope.

If the towed vehicle isn't seeing the towline as thrust, then the exercise
is pointless.

In the case where the towline is not doing anything (there's just enough
tension to balance the weight and drag of the towline), the line should be
vertical at the towed vehicle (if it was forward it would be adding thrust,
and if it was backward, it would be adding drag), and horizontal at the
towplane (if it was above horizontal, there's more tension in the line than
necessary to overcome its weight, and if it's below horizontal, there's not
enough tension.

Line drag's a lot less at FL500. Thrust is 110K, lbs x 4 = 440K (at
sea level :-) I wonder if Kevin Horton can give me max thrust in lbs
in the high 40's for a GE C-90 engine?

This whole thing reminds me of water skiing when I was a kid, and
finding myself at incredible speeds near-even with the driver in a
turn.

I never skiied behind a boat, but there was this thing called the "Cable
Skiway".
They had a cable up in the air, running in a square around four pulleys,
that they could drive at 25 mph or so. The cable had bumps swaged onto it
at regular intervals. You'd sit on their little dock, at one corner of the
square canal that ran beneath the cable, and they'd drop a fork attached to
a towline over the cable, and when the next bump came along, BANG! you were
going 25 mph too.

I managed to stay up after a couple of tries, and then I came to the first
corner. The pulleys were about two feet in diameter. Instead of staying on
the outside of the turn, I cut the corner. So the towline has to go out to
the pulley, and around it, of course... a much longer path than I was
taking, so the line went slack and I slowed down. As I slowed, I sank.
Finally the towline got back out in front of me, and once again, BANG! I was
going 25mph. But the skis were about eighteen inches under water at that
point. I held on to the towline, and I got jerked completely out of the
water. The skis didn't. Well, there didn't seem to be much point to being
dragged through the water without skis, so I let go. I did make it all the
way around, though. Eventually.


pacplyer

Tim Ward