In article ,
A Canuck wrote:
If one was to be asked to design an UltraLight that would be able to
fly on Mars, what would have to change?

Mostly, lots bigger wings. (Lighter gravity, yes, but *much* thinner air.)

Possibly a non-airbreathing engine, since a thin CO2 atmosphere isn't good
for much engine-wise. (There are things that will react with it, but the
options are very limited.) Big propeller.

Would a propellor be efficient at all anyway?

Yes, reasonably so, unless you want to try to fly at very high speeds.

Would it be better to use a balloon/blimp vehicle for controlled
exploration rather than an ultralight?

Probably. They're good at different things, but one advantage of a
lighter-than-air vehicle is that it doesn't need a runway. Much of Mars
is pretty rough and rocky, so you couldn't depend on being able to find a
nice long flat spot to land an airplane... especially since the air is so
thin that landing speeds want to be high.

If you needed an emergency parachute for the ultralight, it would need
to be larger than one on earth?

Much. In fact, it's a tricky thing to do at all. Parachute descent
speeds are rather high for reasonably-sized parachutes.

Is there something else that is missing?
A methane powered engine?

Why methane? If you're carrying both fuel and oxidizer, you want things
that are easily made and conveniently stored. LOX plus liquid CO would
probably be the combination of choice if you're willing to handle
cryogenics -- not as energetic as you might like, but easily made using
all-Martian resources. If you don't want cryogenics it gets stickier, but
monopropellant H2O2 or N2O would be an interesting option -- the latter in
particular has the advantage of not containing hydrogen, which is scarce
on Mars.
--
MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer
pointing, 10 Sept; first science, early Oct; all well. |