Robert J. Bradbury, <email@example.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.