CATS Idea...

I saw this idea on rec.aviation.homebuilt.
I thought it ought to be posted here, so I copied and posted.
The origional idea is NOT mine.
It was posted by Tim Ward


I dunno, but this seems as good a time as any to bring up a stupid,
complicated idea of mine for access to space.

First, you should be familiar with the Kelly Aerospace idea of towing
the spaceship to altitude.
If not, Google for "Eclipse project", NASA, and perhaps F106.

They towed an idling F106 behind a C141 as a proof of concept project.
Second, you should be aware of the "payout winches" used to ground
launch hang gliders. These just pay the line out at a constant
tension, rather than reeling them in at a high rate of speed, as in
sailplane launches.

So here's the scheme:
You build a tow plane about the size of a 747. The payout winch is
mounted such that it "pays out" from the CG of the airplane, on top.
You have somewhere around 100,000 lbs of Vectran tow rope (several
tens of kilometers) on the payout device. This is within the cargo
capability of a 747, though you may want to throw on a couple of extra
engines because of the additional drag.

The spacecraft has a CG hook on the bottom.
You take off, and climb as high as you can, while paying out the tow
line. The spacecraft pilot basically controls the pay out. Pitch up,
and a little more line pays out. Pitch down, and it stops.

If the spacecraft can maintain a 45 degree angle behind the towplane,
it will be 70% of the towrope's length higher than the towplane.

At some point, the true airspeed of the tow plane will not provide
enough airspeed for the spacecraft to continue to climb. So the
towplane starts to turn, and the spacecraft maneuvers to the outside
of the turn. Now it's just like playing "crack the whip". The
air-breathing booster is down in the (relatively speaking) thick
atmosphere at 50,000 feet, while the spacecraft is above most of the
atmosphere at say, 100,000 feet.

That's when the spacecraft releases and fires its rockets.
Because the atmosphere is so much thinner, and the spacecraft is going
faster than it would be at lower altitudes, the increase in peak
altitude achievable should be much higher than just the 50,000 ft
altitude difference between the tow plane and the spacecraft.

After the spacecraft releases, the towplane also releases the towline,
and it descends under a parachute, separately.

There, I feel better.
Tim Ward

Works with water skiing.

I wonder what sort of performance you could get out of it?

How about electrically winching in the space craft. If the tow plane
travels at Mach 1, and the cable is winched in at Mach 1, you have a
Mach 2 launch speed. You'd need a long cable and a very fast reeler.

wrote in message . ..
I saw this idea on rec.aviation.homebuilt.
I thought it ought to be posted here, so I copied and posted.
The origional idea is NOT mine.
It was posted by Tim Ward


I dunno, but this seems as good a time as any to bring up a stupid,
complicated idea of mine for access to space.

First, you should be familiar with the Kelly Aerospace idea of towing
the spaceship to altitude.
If not, Google for "Eclipse project", NASA, and perhaps F106.

They towed an idling F106 behind a C141 as a proof of concept project.
Second, you should be aware of the "payout winches" used to ground
launch hang gliders. These just pay the line out at a constant
tension, rather than reeling them in at a high rate of speed, as in
sailplane launches.

So here's the scheme:
You build a tow plane about the size of a 747. The payout winch is
mounted such that it "pays out" from the CG of the airplane, on top.
You have somewhere around 100,000 lbs of Vectran tow rope (several
tens of kilometers) on the payout device. This is within the cargo
capability of a 747, though you may want to throw on a couple of extra
engines because of the additional drag.

The spacecraft has a CG hook on the bottom.
You take off, and climb as high as you can, while paying out the tow
line. The spacecraft pilot basically controls the pay out. Pitch up,
and a little more line pays out. Pitch down, and it stops.

If the spacecraft can maintain a 45 degree angle behind the towplane,
it will be 70% of the towrope's length higher than the towplane.

At some point, the true airspeed of the tow plane will not provide
enough airspeed for the spacecraft to continue to climb. So the
towplane starts to turn, and the spacecraft maneuvers to the outside
of the turn. Now it's just like playing "crack the whip". The
air-breathing booster is down in the (relatively speaking) thick
atmosphere at 50,000 feet, while the spacecraft is above most of the
atmosphere at say, 100,000 feet.

That's when the spacecraft releases and fires its rockets.
Because the atmosphere is so much thinner, and the spacecraft is going
faster than it would be at lower altitudes, the increase in peak
altitude achievable should be much higher than just the 50,000 ft
altitude difference between the tow plane and the spacecraft.

After the spacecraft releases, the towplane also releases the towline,
and it descends under a parachute, separately.

There, I feel better.
Tim Ward

Works with water skiing.

I wonder what sort of performance you could get out of it?

How about electrically winching in the space craft. If the tow plane
travels at Mach 1, and the cable is winched in at Mach 1, you have a
Mach 2 launch speed. You'd need a long cable and a very fast reeler.

wrote in message . ..
I saw this idea on rec.aviation.homebuilt.
I thought it ought to be posted here, so I copied and posted.
The origional idea is NOT mine.
It was posted by Tim Ward


I dunno, but this seems as good a time as any to bring up a stupid,
complicated idea of mine for access to space.

First, you should be familiar with the Kelly Aerospace idea of towing
the spaceship to altitude.
If not, Google for "Eclipse project", NASA, and perhaps F106.

They towed an idling F106 behind a C141 as a proof of concept project.
Second, you should be aware of the "payout winches" used to ground
launch hang gliders. These just pay the line out at a constant
tension, rather than reeling them in at a high rate of speed, as in
sailplane launches.

So here's the scheme:
You build a tow plane about the size of a 747. The payout winch is
mounted such that it "pays out" from the CG of the airplane, on top.
You have somewhere around 100,000 lbs of Vectran tow rope (several
tens of kilometers) on the payout device. This is within the cargo
capability of a 747, though you may want to throw on a couple of extra
engines because of the additional drag.

The spacecraft has a CG hook on the bottom.
You take off, and climb as high as you can, while paying out the tow
line. The spacecraft pilot basically controls the pay out. Pitch up,
and a little more line pays out. Pitch down, and it stops.

If the spacecraft can maintain a 45 degree angle behind the towplane,
it will be 70% of the towrope's length higher than the towplane.

At some point, the true airspeed of the tow plane will not provide
enough airspeed for the spacecraft to continue to climb. So the
towplane starts to turn, and the spacecraft maneuvers to the outside
of the turn. Now it's just like playing "crack the whip". The
air-breathing booster is down in the (relatively speaking) thick
atmosphere at 50,000 feet, while the spacecraft is above most of the
atmosphere at say, 100,000 feet.

That's when the spacecraft releases and fires its rockets.
Because the atmosphere is so much thinner, and the spacecraft is going
faster than it would be at lower altitudes, the increase in peak
altitude achievable should be much higher than just the 50,000 ft
altitude difference between the tow plane and the spacecraft.

After the spacecraft releases, the towplane also releases the towline,
and it descends under a parachute, separately.

There, I feel better.
Tim Ward

As far as I can see, the main problem with this is how the spacecraft is
meant to climb while attached to the tow-rope. As it gets higher, the
atmospheric pressure drops, and so would the lift across its wings. This
requires either larger wings for high-flying craft (e.g. U2 spyplane) or a
higher velocity...but in this case the velocity is fixed by the tow-plane.
Given that it will be much harder to keep the tow-plane flying fast at
its much lower altitude than a plane at higher altitude I'm guessing this
isn't very efficient.

That's what I thought anyway - feel free to rip my arguments to shreds!

D


On Wed, 30 Jun 2004, Alex Terrell wrote:

Works with water skiing.

I wonder what sort of performance you could get out of it?

How about electrically winching in the space craft. If the tow plane
travels at Mach 1, and the cable is winched in at Mach 1, you have a
Mach 2 launch speed. You'd need a long cable and a very fast reeler.

wrote in message . ..
I saw this idea on rec.aviation.homebuilt.
I thought it ought to be posted here, so I copied and posted.
The origional idea is NOT mine.
It was posted by Tim Ward


I dunno, but this seems as good a time as any to bring up a stupid,
complicated idea of mine for access to space.

First, you should be familiar with the Kelly Aerospace idea of towing
the spaceship to altitude.
If not, Google for "Eclipse project", NASA, and perhaps F106.

They towed an idling F106 behind a C141 as a proof of concept project.
Second, you should be aware of the "payout winches" used to ground
launch hang gliders. These just pay the line out at a constant
tension, rather than reeling them in at a high rate of speed, as in
sailplane launches.

So here's the scheme:
You build a tow plane about the size of a 747. The payout winch is
mounted such that it "pays out" from the CG of the airplane, on top.
You have somewhere around 100,000 lbs of Vectran tow rope (several
tens of kilometers) on the payout device. This is within the cargo
capability of a 747, though you may want to throw on a couple of extra
engines because of the additional drag.

The spacecraft has a CG hook on the bottom.
You take off, and climb as high as you can, while paying out the tow
line. The spacecraft pilot basically controls the pay out. Pitch up,
and a little more line pays out. Pitch down, and it stops.

If the spacecraft can maintain a 45 degree angle behind the towplane,
it will be 70% of the towrope's length higher than the towplane.

At some point, the true airspeed of the tow plane will not provide
enough airspeed for the spacecraft to continue to climb. So the
towplane starts to turn, and the spacecraft maneuvers to the outside
of the turn. Now it's just like playing "crack the whip". The
air-breathing booster is down in the (relatively speaking) thick
atmosphere at 50,000 feet, while the spacecraft is above most of the
atmosphere at say, 100,000 feet.

That's when the spacecraft releases and fires its rockets.
Because the atmosphere is so much thinner, and the spacecraft is going
faster than it would be at lower altitudes, the increase in peak
altitude achievable should be much higher than just the 50,000 ft
altitude difference between the tow plane and the spacecraft.

After the spacecraft releases, the towplane also releases the towline,
and it descends under a parachute, separately.

There, I feel better.
Tim Ward

Alex Terrell wrote:

Works with water skiing.

I wonder what sort of performance you could get out of it?

How about electrically winching in the space craft. If the tow plane
travels at Mach 1, and the cable is winched in at Mach 1, you have a
Mach 2 launch speed. You'd need a long cable and a very fast reeler.


An electric winch that can pull something in at Mach 1? Think about
that.....

...and think about Newton's Third Law. The towing plane will be
slowed to some extent, as well.

--

You know what to remove, to reply....

This is like the parasail boat operation.
The long tether drag is the kill point here. But: It might work with an
ultrathin Buckytube tether.
I wonder if and when such tethers will be available and cheap.


You build a tow plane about the size of a 747. The payout winch is
mounted such that it "pays out" from the CG of the airplane, on top.
You have somewhere around 100,000 lbs of Vectran tow rope (several
tens of kilometers) on the payout device. This is within the cargo
capability of a 747, though you may want to throw on a couple of extra
engines because of the additional drag.
^
//^\\
~~~ near space elevator ~~~~
~~~members.aol.com/beanstalkr/~~~