X-Prize Design Concepts

In article ,
Eric Pederson . retro.com wrote:
For US based teams, FAA reg's would be a problem for this proposal. The
spacecraft would now be operating as a powered aircraft for a significant
portion of the flight (SS1 is classified as a glider).

For FAA purposes, now that it's started doing powered flights with long
burns, SS1 is a suborbital rocket, not an airplane of any type. It flies
under a launch licence.

There is no particular difficulty with suborbital rockets which take off
under power from the ground. XCOR holds a launch licence for such a
design (not yet built).
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(David Harper) writes:

Andrew Gray wrote in message ...
Afternoon all.

The current foremost contender for the X-Prize is, of course, Scaled
Composites - expected to formally announce soon, I believe - which uses
a staged flight method, with horizontal takeoff and landing.

Other contenders use vertical takeoff and landing single-stage vehicles;
Mr Carmack's group, for example.

Have any groups studied - I don't recall hearing of any, so I suspect
no-one ran with it - an in-air refuelling system, or would this be
barred by the competition rules?

What's the real difference between high-alt refueling and
"piggybacking"? Either way, after refueling or release, you're at the
same starting point: 40k to 50k feet up with a full tank.

The refueling aspect adds some complexity.


The refueling aspect adds less complexity than the air launch. The
technical challenges of the latter are usually *vastly* underestimated;
simply dropping a quarter-ton bomb from an airplane without having it
e.g. get caught in the boundary layer and slam back up into the bomber,
is a non-trivial thing. When the air-launched vehicle represents a
much larger fraction of the total weight, and is much less robust than
a simple bomb and thus not amenable to the simple "use big pyros to
kick the thing away so hard it ain't ever coming back" solution,
you're into relatively unexplored territory.

Mid-air refuelling, well, Mitchell Burnside Clapp used to claim that
the United States Air Force alone has done more in-flight refuellings
in a single *day*, than there have been successful air launches of
manned aircraft in the entire history of aviation. I'm not sure if
that's true, but it's certainly within an order of magnitude of true.


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(David Harper) wrote:

What's the real difference between high-alt refueling and
"piggybacking"? Either way, after refueling or release, you're at the
same starting point: 40k to 50k feet up with a full tank.

The refueling aspect adds some complexity.

The essential difference is that the 'tanker' can be a modified
commercial craft, as in USAF practice, as opposed to the large and
specialized aircraft that a non-trivally-sized piggyback launcher
would require.

D.
--
Touch-twice life. Eat. Drink. Laugh.

The mid-air refueling thing is ostensibly the method used for the "Black
Horse'"/"Black Colt" craft. They tank up mid-air on peroxide after taking off a
runway under rocket engine power.

Of course, those are only notional dsigns on paper, it's not like they are real
flight hardware or someth...

hello? Hey, honey, who are thse guys in the....
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