From: hal@finney.org
Date: Fri Aug 20 1999 - 17:20:38 MDT
Robert J. Bradbury, <bradbury@www.aeiveos.com>, writes:
> I would caution against everyone sending an email (like mine :-))
> to Dr. Dertouzos.
Too late. However he is on vacation until Sep 7, according to his
response program.
> It would be more prudent to find out from
> Dr. Minsky, whether or not Dr. Dertouzos is nanotech illiterate
> or nanotech opposed. If it the former, he can be educated and
> we should be tactful about it.
Perhaps I should not have concluded, "...please spare us your crotchety
naysaying when faced with a technology that stretches your ossified mind
beyond its limited ability to accept change." That may not have been
quite as tactful as what Robert had in mind...
> The problems are (a) fuel efficiency -- a jetpack can't carry
> enough fuel to make them useful with current technologies;
> (b) cost -- both jetpacks and air cars are expensive;
> (c) safety -- both types of devices would need improvements
> to guarantee passenger safety.
>
> So, I would say that they are (within an order of magnitude)
> "equally achievable". Since an order of magnitude is probably
> the difference between the cheapest and most expensive cars
> then this may be a reasonable statement.
I think the problem is much more severe for the jetpack, more than
an order of magnitude worse. A flying car is not that different from
an airplane. The big problem to solve is the vertical takeoff/landing.
But jetpacks only last 30 seconds. The fuel is not energetic enough.
And adding more fuel adds weight. It is questionable whether these can
ever work.
Hal
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