Gyros on lasers

> Date: Sun, 10 Nov 91 14:34:24 EST
> From: [email removed]
> Subject: (3096) Gyros on lasers
>
> Carsten, your point is well taken. In fact, lasers SHOULD be treated
> as if they are Gyrostabilized, due to their lack of recoil. But this
> is not stated in the rules; it is merely an application of common sense.

While I am not an expert on gyrostabilization (I have never actually fired
a gun that has it if there are real ones in existence), I don't think that
the main purpose is control recoil.  The effect of a gyro would be to make
the entire gun resistant to quick rotational changes (in any plane).  So you
have 2 choices - a weak (low mass/angular velocity) or strong (high mass/vel)
gyro.  The weak one's only real effect would be to steady your aim (which
would apply to lasers just as well as any other type of gun).  Your aim point
would not jiggle around because the very small unsteadiness in your arm/hand
would be damped by the gyro.  It would do very little to control the amount
or direction of recoil.  A strong gyro (let's ignore the problems with the
materials required to make such a thing that small and light, with
correspondingly HUGE rotational velocity, and what would happen when it was
hit in combat - I wouldn't carry one), one big enough to control recoil, would
a) make the gun impossible to aim - you couldn't track a target with it!
b) would only change the direction of the recoil by 90 degrees - that's what
	gyros do.  so you might end up recoilling to one side instead.
c) the gyro would require HUGE amounts of energy to spin up - all the kinetic
	enery in the spinning gyro if it were perfectly effecient.  Of could
	maybe once you can build such an amazing thing, you could use it for
	battery!

You could try to answer (a) by:
a) only have the gyro engaged (connected to gun frame - you certainly couldn't
	spin it up quickly) just as the trigger was pulled, but it would still
	be hard to track a target with an automatic weapon because the gyro
	would resist the firer.

I think the way to control recoil is to keep the barrel in line with the
firer's shoulder or handgrip as in some bullpup designs today.  Since there is
no moment arm for the force to act through (the recoil force acts directly
toward the support), no rotation would be induced.  There could still be quite
a kick, but it would not mess up your aim (directly anyway).

Once again, my main conclusion is that a practical gyro could only help steady
your aim - anything big enough to help control recoil is probably impossible to
make and too dangerous to use in combat anyway.

> Anyone care to argue that lasers have kick, like in Star Wars? Hmmmm? |->

Well, you could argue that those weren't lasers, since you could watch the
'bolts' fly across the screen.  Certainly subsonic.  Of course maybe you
meant some other 'lasers' I forgot.

Maybe they were actually lasers, but with the light slowed from 'c' to a
few hundred fps - then the photons would have a really BIG mass for the
same energy as a regular photon!  (that was just a joke - really - don't
explain to me about basic physics).

> metlay

Jim Pendergraft

> Date: Mon, 11 Nov 1991 09:57:16 -0500
> From: [email removed] (Jim Pendergraft)
> Subject: (3099) Re: (3096) Gyros on lasers
>
> > Date: Sun, 10 Nov 91 14:34:24 EST
> > From: [email removed]
> > Subject: (3096) Gyros on lasers
> >
> > Carsten, your point is well taken. In fact, lasers SHOULD be treated
> > as if they are Gyrostabilized, due to their lack of recoil. But this
> > is not stated in the rules; it is merely an application of common sense.
>
> While I am not an expert on gyrostabilization (I have never actually fired
> a gun that has it if there are real ones in existence), I don't think that
> the main purpose is control recoil.  The effect of a gyro would be to make
> the entire gun resistant to quick rotational changes (in any plane).  So you
> have 2 choices - a weak (low mass/angular velocity) or strong (high mass/vel)
> gyro.  The weak one's only real effect would be to steady your aim (which
> would apply to lasers just as well as any other type of gun).  Your aim point
> would not jiggle around because the very small unsteadiness in your arm/hand
> would be damped by the gyro.  It would do very little to control the amount
....
> Once again, my main conclusion is that a practical gyro could only help steady
> your aim - anything big enough to help control recoil is probably impossible to
> make and too dangerous to use in combat anyway.

    I'm going to quote from '3G', the BTRC's gun design book (and a
must buy, I should say):

        "Any weapon may be gyrostabilized.  This will add ... to the
    overall mass of the weapon (heavier weapons require heavier gyros),
    and is only possible at TL9 [WWII] or greater....  Hand weapon
    gyrostabilization operates on 6 gyros, with two counterrotating
    gyros on each axis, usually near the weapon's center of gravity.
    Pressure switches in the grip of the weapon speed up or brake
    certain gyros, depending on which way the weapon is moved, resulting
    in the weapon automatically pivoting in that direction.

        "Example - If the firer twisted the grip to the right, the
    weapon would smoothly pivot to the right, regardless of anything
    else the firer was doing, including running.

        "The extremely stable mount gyrostabilization provides will
    halve negative modifiers for firer movement ... but automatically
    makes the initiative of the weapon 1 worse...."

    From this I conclude that the usual use of gyrostabilization is
not so much to control recoil (you will still get a kick -- it can't
stop that) but to keep the gun steady.  Now there are cases (like
snap shots) where that can prove quite a hindrance even if you can
control the gyros (as it states above).  But for any rifle-sized weapon,
it makes sniping much easier.

> > Anyone care to argue that lasers have kick, like in Star Wars? Hmmmm? |->
>
> Well, you could argue that those weren't lasers, since you could watch the
> 'bolts' fly across the screen.  Certainly subsonic.  Of course maybe you
> meant some other 'lasers' I forgot.

Who knows?  They played enough havok with current physical theory in
those movies that you could probably justify anything... :)

> > metlay
>
> Jim Pendergraft

Jack Dietz.