Re: Sometimes physics is fun

[Bernard Cleyet <anngeorg@PACBELL.NET>]

Back in the fifties there was a question (Physics class) how to power
for a short time an orbital rocket's radio, etc.  I think it was obvious
a chemical fuel, despite its limited engineering and thermodynamic
inefficiency, had a higher specific energy (J/kg) than a Pb-acid
battery.  I suspect a Pu - thermoelectric cell "beats all".  Only for
long term tho.

Great ? for a class. Brian.

bc

Brian Whatcott wrote:

> At 08:48 PM 10/26/2003, you wrote:
>
>
> > How big are these things?
> >
> > I like fire extinguishers (the acid - bicarb. and water may have more
> > "oomph" than a CO2) or SCUBA tanks.
> >
> > bc
>
>
> It seems to me there is enough intellectual fire power present to
> rationally estimate the potential of various propulsion modalities.
>
> Not a 'specific impulse' kind of deal, necessarily: more
> an available energy density estimate.
> I would like to see estimates for a gas capsule,
> a pressurized gas and water bottle,
> a model rocket engine
> an electric motor - lithium cell arrangement
> a model diesel or glo plug engine with a few ccs of fuel.
>
> I fancy the last mentioned method is up there.....
>
>
> Brian Whatcott    Altus OK    Eureka!