RE: [SG,DS] Power Armour Weapon

Well, yes there are a lot of variables - temperature of the gasoline and
air as they enter an engine for example can both act as a coolant for an
engine, the circulating oil acts as another cooling system for an
engine, the sheer mass of an engine block as a heat sink, the fact that
most engines run at high energy output (lots of RPM's) also happen to be
traveling very quickly (100 kph+) which aids in cooling. I don't think
that most car manufacturers would suggest that running your car in
neutral at 6000+ RPM for 10 minutes is a recommended practice let alone
hours and hours on end.  

In addition, car radiators are not completely closed systems.  If they
were, you'd never have to re-fill the reservoir.  In emergency, they are
allowed to boil over - taking excess heat away as the fluid evaporates
and reducing dangerous pressure. The fact that they have this planned in
shows that they are not a total solution - you still fall back on
evaporation to take care of really large heat loads.

--Binhan

> -----Original Message-----
> From: Imre A. Szabo [mailto:ias@sprintmail.com]
> Sent: Tuesday, March 11, 2003 3:56 PM
> To: gzg-l@csua.berkeley.edu
> Subject: Re: [SG,DS] Power Armour Weapon
> 
> 
> > A gallon of gas weighs approximately 2.8 kg, so if you burn 
> 10 gallons an
> hour you have released 322 Kcal of energy.  If in one hour you fire a
> conservative 100 rounds per minute, 1 gram of propellent per 
> bullet, you
> release 4,308 Kcal of energy.  Multiply by 4 for 400 rounds 
> per minute that
> is being discussed.
> >
> > Note that the 1 gram per bullet is probably low, I couldn't 
> find a number
> for grains of propellent in 7.62 NATO, but 1 grain is 0.648 
> grams, so two
> grains would be 1.296 grams.	For comparison, most .45 ammo 
> is loaded to 5
> or 6 grains of smokeless powder.
> 
> There's a big problem with this; you're leaving out a 
> critical variable.
> The brass casing acts as a heat sink and absorbs a lot of the heat and
> removes it from the system when the casing is ejected.  Car 
> engines don't
> have anything similar to this.
> 
> This is also what made caseless ammo such #$^%$@@ to get to 
> work.  HK teamed
> up with Dynamite Noble and ended up using a propellent 
> derived from solid
> rocket fuel, not traditional gun powder to get a propellant 
> that wouldn't
> cookoff.
> 
> ias
> 
>