Re: RR, High tech and misc - was RE: [SG2] weapons

Binhan Lin wrote:

 >Possible solutions:
 >
 >Current recoiless rifles are heavy for several reasons:
 >1) the rounds themselves are pretty hefty - upwards of 5 kilos

As opposed to ATGMs, which tend to be in the 15-25 kg range (at least
for 
man-portable ones; air-launched monsters like Maverick and Hellfire are
of 
course much heavier). The RR round uses a much larger proportion of its 
total weight on the warhead than the ATGMs do though.

 >2) Penetration is roughly based on warhead diameter, to get decent
 >penetration you need a wider warhead, which adds to the weight and
 >decreases the aerodynamic width to length ratio.

Weight yes, width:length ratio no. For a given liner shape (usually a
cone 
or a kind of trumpet bell-shape) the length of a HEAT warhead is by 
necessity very close to proportional to its diameter. If you just
increase 
the diameter without increasing the length you have to use a flatter
cone, 
and reduces the penetration:diameter ratio.

 >3) Targeting systems are often integrated onto the weapon itself
adding
 >more weight

Targetting systems for RRs and similar weapons are almost invariably 
detachable nowadays (ie. NOT integrated onto the weapon itself in the 
strict sense of the word; you can let someone else carry them and only
snap 
them on when you prepare to fire) - unless you count the basic iron
sights 
of course, but they don't weigh more than a few grams.

 >4) the weapons needs to be reusable, and rapidly so, long cooling off
 >periods are not suitable for sustained combat use.

I've never heard about any RRs where overheating was a problem. The
reload 
time is enough for the first few shots, and after that you'll need to 
get  moving PDQ anyway to avoid the return fire.

 >Automatic loading from pre-loaded "magazines" or clips that allow
rapid fire

These increase the weight of either the (unloaded) weapon itself, or the

rounds, or both. OK for vehicle-mounted weapons, but dubious if you want

something man-portable... also, when you're lying prone trying to be 
invisible, having a big ammo dropper on the top of your weapon does your

signature no good at all. Yes, I know that GZG makes three-round
launchers; 
to me they look rather impractical :-/

 >Separate or higher tech detachable sights - For instance the operator
 >merely points the gun in the target's general direction - it looks for
a
 >targeting or rangefinding laser mark in the vicinity and fires. The
rounds
 >themselves are semi-guided and home in on the laser mark.

In that case the round is effectively an ATGM, with all the extra costs
and 
weights that entails. The laser mark is also very easy for the target to

detect, allowing it to initiate counter-measures much sooner.

 >Two-stage hyper-velocity rounds

...are definitely ATGMs with a full guidance and manoeuvring package,
since 
a booster engine that powerful will wreck the accuracy of unguided
rounds. 
'Course, when you already have a full guidance and manoeuvring package 
together with this extremely powerful booster engine, you don't need an
RR 
to launch it from - a plastic launch tube and a low-power launch rocket 
will do just as nicely... and you've just described LOSAT :-/

 >- current rounds fire all their fuel in a single burst within the gun

There are plenty of two-stage RR rounds available - eg. every single one

fired from an RPG-7, or the modern Carl Gustaf HEAT rounds (551 and
751). 
The speed increases provided by their in-trajectory engines are
relatively 
moderate though, due to the accuracy problems mentioned above - it's 
biggest in the RPG-7 (some of its grenade types are boosted from about
100 
m/s to about 300 m/s), but the accuracy suffers accordingly.

(Yes, the RPG-7 launcher is technically an RR with a caliber of 40 mm.
The 
grenades themselves have booster rocket engines however, which is why
the 
weapon is called "RPG" - Rocket Propelled *Grenade*. FWIW our AT-4 is of

course also an RR and its grenades don't have *any* rocket engines 
*anywhere*, in spite of the various US armed forces who insist on
calling 
it a "rocket launcher" :-/ )

Later,

Oerjan
oerjan.ohlson@telia.com

"Life is like a sewer.
  What you get out of it, depends on what you put into it."
-Hen3ry