Re: SPACE: Roton in New Scientist
Tue, 11 Aug 1998 10:31:39 -0700 (PDT)

Michelle Jones [] wrote:
> you fire the rocket from a 20 km altitude. turns
>out, the extra
>altitude gains very little over starting on the ground.

Actually you gain a lot because you can use nozzles with an expansion ratio optimized for vacuum, not surface pressure. This was one of the smart elements of Kistler Aerospace's first pseudo-SSTO design; they had a reusable rocket which just lifted the main vehicle to 80,000 feet and released it, which saved enough fuel from switching to vacuum nozzles to greatly increase the payload capacity.

>right. however, rotary blade flight is not particularly efficient.

And the original Roton design didn't get much of its lift from the rotors, as far as I remember. The engines were mounted on the ends of the rotors and turned from horizontal to near vertical as it ascended, so that not long after launch it was propelled largely by rocket thrust. The main advantage was the simplicity of the engine design and that you did get the extra lift from the rotors.

>i hate
>to be in the she'll-never-fly-orville crowd, but michael, i can assure you my
>friend, the roton will not fly. nooooo way.

Wouldn't bet on it myself; and remember, if it does fly that message will be on the web site for all eternity, or at least until the Singularity ;-).