From: chem7l@jane.uh.edu
Subject: Re: Military Mechs?
Summary:  Long technological monologue to bore most normal people.
News-Software: VAX/VMS VNEWS 1.41    
Organization: University of Houston
Date: Tue, 28 Jul 1992 20:11:00 GMT

In article <1992Jul28.161435.89577@vaxc.cc.monash.edu.au>, jwadsley@vaxc.cc.monash.edu.au writes...
>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:
>> [Stuff about how BattleTech technology is supposed to work.]

>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. 

You have a point.  I always assumed that an efficient method of converting heat
to electricity had been produced.  After all, they produced an efficient method
of converting light to electrical energy, and that is almost as difficult.  It's
really just a matter of finding the right crystalline structure with the correct
composition to cause electron migration in a given direction when heated.

Also, I am not trying to defend FASA's interpretation of technology.  In my
earlier posting I was just trying to clarify how things worked _according to
FASA_.  I admit the game is on weak legs technologically, but I think
the game is successful because some of its unrealistic rules put players in
certain situations that can be tactically and strategically challenging.

>If you are working in comparable realities, then combustion and fusion engines
>both produce heat and thus work on reasonably similar bases. 

Sorry, but this is simply wrong.  Fusion engines do create mostly heat energy, 
though a good deal of light would be released as well.  Internal combustion, 
however, produces heat almost as a side effect.  Actually, the piston
compresses an air/fuel mixture which is then ignited by a spark.  The resulting
chemical reaction then breaks the fuel into several gas molecules.  The extra 
gas molecules, along with the added heat, cause a sudden increase in pressure
(an explosion) which drives the piston into the open position.  Thus, the 
engine effectively turns chemical energy into mechanical energy in a pretty
straightforward mechanism that takes advantage of entropy changes as well.  

This is not very similar to a fusion engine, which uses the heat released by a
nuclear fusion reaction as heat energy.

>It is hard to get
>more detailed because it is hard to predict the evolution of both combustion
>and fusion engines. 

True.

>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.

This is impossible to say.  Really you are talking about apples and oranges.  An
internal combustion engine gets all of its energy from chemical reactions, while
a fusion reactor gets its energy from nuclear reactions.  Several thousand times
as much mass is converted to energy in a nuclear fusion reaction, so a fusion
engine has a much greater potential energy output than any internal combustion
engine will ever have.  There is simply never going to be a comparable amount of
energy in chemical bonds, and internal combustion engines are already 
approaching the absolute limits on energy efficiency.  Only new fuels with more
energetic (and probably not very stable) bonds can increase the energy output
beyond these limits, but even these will never hold amounts of energy comparable
to fusion reactions--it's simply impossible as it would cause spontaneous 
nuclear reaction instead.

>If mechs run on electricity then they need two more steps than standard
>vehicles. 
>Mech: Heat - Mechanical - Electrical - Myomer
             ?^^^^^^^^^^?
No, the 'Mech has no need of a Mechanical energy step, as the myomers _are_ the
means of converting electrical to mechanical energy.  Also, it is entirely 
possible that the myomers convert the electrical energy to mechanical energy at
almost 100% efficiency, but even if they don't the fusion engine can produce so
much more energy that it doesn't matter.

>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.

Conversion of electricity to mechanical energy is not _that_ efficient, but you
do have a point.  Fusion engines should work in vehicles as well as they do in
'Mechs.  But the game wasn't designed to be technologically accurate, it was 
designed for fun and with the game balance weighted in favor of 'Mechs to make
them the masters of the battlefield. 

>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 ).

I agree that there is no real basis for 'Mechs to be better than vehicles 
(though I have invented a fake one, see a previous posting of mine).  However,
there is NOTHING _MAGICAL_ about the ability of fusion reactions to produce 
several thousand times as much energy as chemical reactions.  That's just 
Einstein's equation at work.  IC engines probably could not produce the amount
of energy required to fire an energy weapon without requiring a power plant and
capacitor array the size of a city block, while fusion engines conceivably 
could.  This may be the reason FASA decided to make fusion engines so much 
lighter for the same energy output, and it does make sense _IF_ the energy 
output is _VERY_ high.  The energy necessary for movement doesn't approach
this, but the energy required for lasers that can reduce light buildings to 
rubble in two shots _WOULD_ be out of the range of a vehicle-sized IC engine,
but may not be out of the range of a vehicle-sized fusion engine.

>James Wadsley.

Jim Corbit
Newsgroups: rec.games.frp.misc