Tethered wings.

"Pete Lynn" wrote in message ...
"Len" wrote in message
om...

Pete, this is a very interesting--and reinforcing--
statement on rigid designs, coming from a member of
perhaps the world's premier kite family. I am encouraged
to continue to pursue the "huge ultralight" aircraft
approach for the design of a carrier aircraft for space
launch. Allowing an orbiter to start life above much of
the atmosphere appears to be a surprisingly large
advantage. And--as you have pointed out--getting there
does not have to be as difficult or expensive as generally
thought.

Thank you.

Have you given any thought to the idea of taking a cheap powered
hanglider or ultralight, and putting a small rocket on the back and
going for a few altitude records?

Yes. Pat Kelley has even offered to lend us a few of Vela
Technology Development's Atlas vernier rockets. It would be
interesting, but I wouldn't expect to get very high.

From what I can tell, you should be able to get to 20-30 km very cheaply
indeed, (a few tens of thousands of dollars?), though I am not so sure
about the pilot life support systems. I expect it would be a very
interesting ride and that people would be sure to take notice.

....pressurized capsule plus oxygen mask--as per our
X PRIZE plan.

I would be interested to hear any quick numbers, technical design
comments or possible applications. (supersonic skydiving, sounding
rockets, photography, etc?) To my knowledge this is a very cheap and
constructive stunt that has not been done before. A few obvious
potential sponsors come to mind.

I don't think we could set a new record with a standard
ultralight with a rocket. One of our goals is to use a
180 m^2, rocket-powered, fabric-covered aircraft to get
to 37.5 km without staging. Our current wing design
looks like we could hold wing mass to about 720 kg
(4 kg / m^2) at 180 m^2. Ths structure is unusual.

Yes, we're actively looking for sponsors at $1/cm^2
(minimum US$10 on PayPal)--see our web site.
There's plenty of room for $1 million worth of sponsors
on the large wing. We would, of course, welcome one big
sponsor, as well as a lot of small sponsors. I think this
vehicle could be designed, built, tested and flown within
a $1 million budget.

As a carrier for space launch, we should be able to launch
about a one-tonne, expendable, upper-stage package to
above 30 km and put a 20-kg or larger satellite into LEO
with the 180 m^2 wing.

This carrier would also serve as a one-tenth-size (re wing
area) demonstrator for our Space Van 2009, which could carry
a pilot and five passengers to an ISS or Bigelow type orbit.


Pete.

Best regards,
Len (Cormier)
PanAero, Inc.
(change x to len)
http://www.tour2space.com

"redneckj" wrote in message ...
"Len" wrote in message
om...

Pete, this is a very interesting--and reinforcing--
statement on rigid designs, coming from a member of
perhaps the world's premier kite family. I am encouraged
to continue to pursue the "huge ultralight" aircraft
approach for the design of a carrier aircraft for space
launch. Allowing an orbiter to start life above much of
the atmosphere appears to be a surprisingly large advantage.
And--as you have pointed out--getting there does not have
to be as difficult or expensive as generally thought.

Hypothetical question Len. If it were possible to reduce
the vortex/induced drag on a very low aspect ratio wing
to the point that it was competative with high aspect ratio
wings, would it be possible that a rigid wing vehicle
could beat the kite wing concept? This is assuming that
an aspect ratio of 2 could perform at the levels of aspect
ratio 10 or so.

Actually, this is a quite interesting possibilty. During
the past week, I have been revisiting our old "Windjammer"
and Windjammer/Boeing RASV concepts using much lower wing
loadings that might make sense with an "ultralight" approach
to low aspect ratio wings. Dan Raymer points out on page 20
in "Aircraft Design: A Conceptual Approach," that "wetted
aspect ratio" is a more reliable conceptual-level indicator
of lift-to-drag ratio than aspect ratio. Raymer points out
that the AVRO Vulcan with an aspect ratio of 3, but relatively
low wetted area has an L/D almost as good as the B-47, which
has an aspect ratio of 9.4. Moreover, my trajectory analyses
of carrier aircraft with low dynamic pressure climb and
acceleration suggests that the actual L/D is not all that
different for real trajectories. For this reason, I suspect
that an aspect ratio of only 2 may be quite appropriate.

I have also been able to show superior performance for the
carrier aircraft by allowing the carrier aircraft to go
supersonic at very low dynamic pressures. I think
lightweight skin--perhaps even fabric--could work up to a
transient mach 2.5 at sufficiently low dynamic pressures.

I only noticed your post today--but I wanted to note that
I think that it is timely and has merit.


I'm not suggesting I have the answer now, just a lead that
may or may not be worth investigating.

Best regards,
Len (Cormier)
PanAero, Inc.
(change x to len)
http://www.tour2space.com