I have to say that the several seconds around and after liftoff are
quite dangerous for an airplane.

Right before I soloed my instructor went over the options for engine
failure while on the upwind (from takeoff until the first turn in the
pattern) at Reid-Hillview. There were none that I found very acceptable
- a schoolyard and a few city streets for runways 31L&R. On runways
13L&R there is a mall parking lot (or the roof - a Cessna did manage to
land on the mall roof!). A rocket plane gives a few more options than an
underpowered Cessna, the critical point being when the vehicle has
enough energy to give the pilot options, generally the altitude at which
you can turn around and make it back to the runway. Also some airports
(such as Mojave) have multiple runways which may help. The not yet
mentioned problem with, oh say, Xerus is that it may gain altitude a lot
quicker than a Cessna, but it will also lose altitude in the glide a lot
faster than a Cessna.

VTVL and HTHL have their respective advantages and disadvantages, VTVL
has some challenges in regards to engine out scenarios, HTHL has a much
reduced problem with engine out (but still has some problem). VTVL is a
much simpler structural design problem, HTHL has more complexity and
carries all that extra weight. On the other hand, one can add a lot of
weight trying to compensate for the failure modes of VTVL (adding
chutes, crash bags, etc.) 

IMHO, VTVL comes out ahead mostly because I see an easier development
path going from suborbital to SSTO VTVL.

There is only one way to find out which is better - build and fly both.

Dave
-- 
David Masten <[EMAIL PROTECTED]>
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