From: jwadsley@vaxc.cc.monash.edu.au
Newsgroups: rec.games.frp.misc
Subject: Re: Military Mechs?
Date: 28 Jul 92 16:14:34 +1000
Organization: Computer Centre, Monash University, Australia

In article <27JUL199217362646@elroy.uh.edu>, chem7l@jetson.uh.edu writes:
> In article <55239@mentor.cc.purdue.edu>, jacobus@mentor.cc.purdue.edu (Bryan J. Maloney) writes...
>>In article <1992Jul25.002200.1503@news.columbia.edu> jhk6@cunixb.cc.columbia.edu (John H Kim) writes:
> 
>>>Mechs rely on a different type of motor than tanks do.
>> 
>>First, assuming that the "different motor" relied upon is some sort of
>>pseudo actino-myelin ("synthetic muscle") analog, there is no reason whatsoever
>>why a tank could not use the EXACT SAME MOTOR!!!!!!!!!!
>> 
>>After all, it is very simple to transfer linear motion into circular motion
>>(It's called a piston).
> 
> Just to clear things up:
> BattleMechs use a fusion power plant, the main purpose of which is to generate
> electricity.  The "synthetic muscles" contract when exposed to electric current.
> Thus, the BattleMechs' fusion engines generate the energy needed for locomotion
> directly.  On the other hand, vehicles have to have electric motors to convert
> this electricity into mechanical energy.  Of course, they could just use myomer
> fibers, but the myomer fibers probably don't contract fast enough to effectively
> drive the pistons.  Thus, vehicles which require wheels or fans to move at high
> RPMs require extra drive equipment.  That is why vehicles with fusion engines 
> require drive equipment equal in weight to half the weight of the engine -- 
> larger fusion engines produce more electricity and therefor require larger 
> electric motors to convert that electricity to mechanical energy.  On the other
> hand, internal combustion engines produce mechanical energy directly, but they
> do not produce anything like the same amount of electricity.  Thus, no drive
> equipment is required, but energy weapons cannot be used without power 
> amplifiers.  Also, internal combustion engines require fuel, which _partly_
> explains the fact that internal combustion engines weigh twice as much as 
> equivilent fusion engines.  I've always assumed a rather large fuel reserve, as
> battletech is not strong on logistics.  If you want more realism, however, you
> may want to make IC engines smaller.  However, you should also make power 
> amplifiers MUCH larger, as lasers, PPCs, etc. use MUCH more electricity than an
> IC engine will provide.  In the interest of simplicity and game balance, I tend
> to follow the standard rules.

Hang on here. Fusion engines produce electricity directly? Since when. I
haven't read Battletech in detail but if this is an assumption then this little
garbology has to rank as one of the worst flaws in Battletech. 

If you are working in comparable realities, then combustion and fusion engines
both produce heat and thus work on reasonably similar bases. It is hard to get
more detailed because it is hard to predict the evolution of both combustion
and fusion engines. Combustion engines need more weight of fuel but do not need
heavy shielding which both mechs and vehicles should use. Thus there is no
reason for a similarly rated engine to weigh differently in mech or vehicle.

If mechs run on electricity then they need two more steps than standard
vehicles. 
Mech: Heat - Mechanical - Electrical - Myomer
Vechicle: Heat - Mechanical

Even if fusion engines do produce electricity directly, there is no reason why
it can't be easily converted into mechanical energy via the usual means, which
is very efficient. If vehicles have extra weight that is an electrical engine 
then mechs have that weight as myomer fibres.
Mech: Heat -(magic)- Electrical - Myomer
Vechicle: Heat -(magic)- Electrical - Mechanical

Anyway a comment on energy conversion:
   heat to mechanical - inefficient
   mechanical to electrical - efficient
   electrical to mechanical - efficient
   heat to electrical - not possible as far as I know

Disclaimer: I haven't looked at this stuff for years!

There is no scientific basis on which to argue that mechs are more efficient
than normal vehicles. This applies to energy usage and weight of engines and
power sources. 

I think we are getting to the heart of the thing here. This magical efficiency
of myomer and fusion engines compared to everything else appears to be a major
assumption behind the existences of 'mechs' ( Size and shape arguements put
aside ).

James Wadsley.
Newsgroups: rec.games.frp.misc