Making Gyrocs Great - Page 3

Varyon · 11-13-2019, 05:13 PM

I had some thoughts with the 25mm Payload Rifle discussion that are best put in another thread - namely, how to make gyrocs useful. Let's start with how things stand.

Pros:
Lightweight, low ST weapon
Exceptional damage and payload capability for their small versions
Extreme 1/2D range
Incredible velocity for micromissiles

Cons:
Heavy, expensive ammo
Poor damage for their larger versions
Cannot benefit from ETC
Small Max range
Low Acc compared to conventional weapons
Micromissiles cost more than comparable "smart" bullets

These are the RAW Pros and Cons, but there should be others. First off, their flat trajectory means distance to target doesn't matter as much as for conventional weapons. This would give results comparable to having a rangefinder, but not quite as good - I'd call it +2 to hit, although this should probably be negated if the target is moving laterally quickly enough to cause a penalty and it doesn't stack with the bonus from having a rangefinder. Next, APDS and APEP don't really make sense for gyrocs, because discarding sabots aren't going to help them.

Next up, we need to resolve some of the oddities of gyrocs. This is where we're getting solidly into houserule territory. First off is the ridiculous velocity of micromissiles (1900 yards/sec, over Mach 35). If we assume a similar mass fraction of fuel to payload as Spaceships conventional weapons (which also follow the same trend as missiles), we'd expect a 1.5cm missile to be 1/10000 tons and deal around 2.5d dDamage at 1 mile per second (1760 yards/sec). Gyrocs are about half that weight and deal around 1/4 the damage. If we assume the reduced weight is due more to having less propellant than having a smaller payload, that implies a velocity of around 440 yards/sec, on the low end of rifles. Which, honestly, doesn't seem too bad. I'd probably bump it up to 500 (on par with the IML and similar).

Next up is the cost of micromissiles when compared to smart bullets. Normal gyrocs already have most of what a micromissile needs (adjustable flight surfaces, which they need to rely on for stability) and mostly just need a guidance system, while normal bullets lack any such. It may be appropriate to reverse the relationship, with smart bullets having a base cost of 10x the cost of normal bullets and gyrocs being micromissiles by default. Personally, I'm inclined to go with 10x for smart bullets, 2x for micromissiles (so base of $10 instead of $50), and make guidance systems be a flat additional cost (there's no reason a skill 14 guidance system for a 15mm projectile wouldn't work installed in a 64mm projectile, provided the software was adjusted properly); higher cost systems should also be available for a higher price, but that's a digression.

Finally, there's the oddity of lacking a 1/2D range - apparently, the bullet just stops once it runs out of fuel, rather than continuing on a natural ballistic trajectory. HT has +P give the same boost to damage and range, and UT has ETC do the same. Applying this same concept to the 15mm Magnum pistol -> 15mm gyroc -> 15mm antimateriel rifle/Heavy Chaingun, the gyroc is x1.4 to damage compared to the pistol round, x0.4 to damage compared to the rifle round. Applying the same to range, we get 329/3640 converting from the pistol, 800/3600 converting from the rifle. The gyroc's aspect ratio is probably closer to that of a rifle bullet than that of a pistol, but probably not by a lot; I'd call it 600/3600. That means the gyroc has a velocity of 500, has a flat trajectory (+2 to hit) out to 1900, has a 1/2D of 2500 (1900+600), and a Max of 5500 (1900+3600).

With all that out of the way, let's explore some potential additional options for gyrocs. Skip down to tl;dr for statistics without discussion.

Hot Gyroc: This is a gyroc designed to burn through its fuel at a greater rate, in order to achieve a higher velocity. Looking at things simplistically (which is probably wrong, as we're supersonic, but it's the best I can do), GURPS damage scales linearly with velocity, while the power required scales with the square of velocity. A 9d pi++ gyroc would have move 750, but would burn through fuel at 2.25x the normal rate, running out in 1.69 seconds instead of 3.8 seconds, so it would only travel around 1250 yards in that time (giving it Range 1850/3850). You need a more robust engine to manage the increased output - I'd say multiply CPS by the cube of the damage boost. The best you can manage is x2 speed, for move 1000, flat trajectory out to 950, Range 1550/3550, and x8 cost.

TL 10: Better propellants allow you to run "hot" by default. A baseline TL 10 gyroc is 9d pi++, move 750, has a flat trajectory out to 2850, and has Range 3450/6450. This is extrapolated from the way missile launchers work; one could continue the progression, for x2 at TL 11 and x3 at TL 12.

Long Gyroc: This is a longer gyroc, with more fuel for a longer burn. If we assume a gyroc's payload is a 15mm sphere of lead, it would weigh 20 g out of the total of 45 g of a gyroc. Sadly, nothing TL9 in Spaceships has sufficient performance to reach Move 500 within 10 yards, but if we assume roughly 50% of the remaining weight is the rocket engine and 50% is the fuel, that means around 12.5 g of fuel (a 27.8% mass fraction) gets us to 1900 yards before it runs out. Cribbing from the simplified rocket equation calculations from Spaceships - and rounding up to 30% - this implies every 5% of mass that is fuel would give around 265 yards (prior to rocket equation adjustments). A 15mm gyroc round is assumed to be able to fit in the grip of a pistol, but how long would it be? If we assume the fuel+casing and rocket are equal in density, and about half as dense as the payload, a 15mm wide cylinder weighing 25 g would be around 22.5 mm, for a total length around 37.5 mm. I think the general rule of thumb for something comfortable to grip in the hand is around 1" of width, or about 25 mm - the gyroc length is already far enough beyond this by the above simplistic calculations I think it's safe to say the grip is around the maximum one can comfortably handle. That in mind, Long Gyrocs probably have to be loaded elsewhere than the grip; a bullpup configuration may make the most sense.
A double-length gyroc is probably around the largest such a round can get. With a 20g payload and 11.5g rocket (remember, we rounded fuel up to 30%), and 1.11g/mm for case+propellant, we're looking at maximum of 55g propellant in a 86.5g rocket, or around 65%. That's good for 3445 yards before rocket equation adjustments, or around 5500 after. This would be a 0.2 lb gyroc. The rocket is probably the most expensive part of a standard gyroc, so set price to x1.5 or so.

Other sizes: Gyrocs of other sizes are fairly easy to work out - assuming the rocket scales fine with size (which admittedly may not be the case), velocity/flat range stays the same, damage scales linearly with caliber, and weight/cost scales with the cube of caliber. I'll leave it up to others to come up with the stats for launchers.

tl;dr: Note I've rounded some values to make things a bit more presentable

Standard Gyroc: 6d pi++, range 2500/5500. +2 to hit within 2000 yards if not using rangefinder. 0.1 lb, $5

Micromissile: Must have Guidance Package (see below). Range standard for gyroc; Move 500. No range penalty (Guided/Homing). x2 CPS plus cost of Guidance Package (see below).

Smart Bullet: Must have Guidance Package; unavailable for gyroc. Range standard for weapon; Move 300 for pistols, 600 for rifles (x1.5 for ETC). No range penalty (Guided/Homing). x10 CPS, plus cost of Guidance Package. Skill (6+TL).

Guidance Package: Required for Micromissiles/Smart Bullets. May be Guided, Viper, Multi-Spectral, or Multiscanner. See UT146 for the last three.
Guided: Requires user to maintain "lock" on target until impact, but uses user's skill. $50.
Viper (TL9): $150
Multi-spectral (TL10): $500
Multiscanner (TL^): $500

TL 10: At TL 10, the standard gyroc improves to 9d pi++, velocity 750, flat range 2850, range 3450/6450. Optionally, boost to 12d pi++, 1000, 3800, 4400/7400 at TL 11, 18d pi++, 1500, 5700, 6300/9300 at TL 12. No change in WPS/CPS.

Hot Gyroc: x1.5 to damage is x1.5 to velocity, x0.7 to flat range. x3 CPS.
x2 to damage is x2 to velocity, x0.5 to flat range. x8 CPS.

Flight Gyroc: Not generally available for gyroc pistols (requires loading individually, or with a bullpup configuration). Hot and Flight are often combined and offset each other. (Changed the name because Hot Long Gyroc sounded... yeah).
x1.5 flat range is x1.2 WPS and x1.1 CPS.
x2 to flat range is x1.5 WPS and x1.2 CPS.
x3 to flat range is x2 WPS and x1.5 CPS.

Reactionless (TL^): Replaces fuel with an energy bank and rocket with reactionless thruster. Standard is x5 to flat range and x2 CPS; can be combined with Hot and Flight.

Other sizes: Note, TL is just a suggestion (it assumes gyrocs are one size category less finicky than the Viper guidance package); additionally, damage is listed as for TL 9, regardless of actual TL. Largest caliber is 40mm as 64mm is an IML.

Code:

TL	Cal	Damage		WPS(lb)	CPS($)
9	40mm	15d pi++	2	100
9	25mm	10d pi++	0.5	25
9	18.5mm	7d pi++		0.2	10
9	15mm	6d pi++		0.1	$5
9	10mm	4d pi+		0.03	1.5
10	7mm	3d pi		0.01	0.5
11	5mm	2d pi		0.003	0.15
12	3mm	1d+2 pi-	0.001	0.05

So... thoughts? Does this look like it would make gyrocs a bit more usable?

11-13-2019, 05:13 PM	#1
Varyon Join Date: Jun 2013	Making Gyrocs Great I had some thoughts with the 25mm Payload Rifle discussion that are best put in another thread - namely, how to make gyrocs useful. Let's start with how things stand. Pros: Lightweight, low ST weapon Exceptional damage and payload capability for their small versions Extreme 1/2D range Incredible velocity for micromissiles Cons: Heavy, expensive ammo Poor damage for their larger versions Cannot benefit from ETC Small Max range Low Acc compared to conventional weapons Micromissiles cost more than comparable "smart" bullets These are the RAW Pros and Cons, but there should be others. First off, their flat trajectory means distance to target doesn't matter as much as for conventional weapons. This would give results comparable to having a rangefinder, but not quite as good - I'd call it +2 to hit, although this should probably be negated if the target is moving laterally quickly enough to cause a penalty and it doesn't stack with the bonus from having a rangefinder. Next, APDS and APEP don't really make sense for gyrocs, because discarding sabots aren't going to help them. Next up, we need to resolve some of the oddities of gyrocs. This is where we're getting solidly into houserule territory. First off is the ridiculous velocity of micromissiles (1900 yards/sec, over Mach 35). If we assume a similar mass fraction of fuel to payload as Spaceships conventional weapons (which also follow the same trend as missiles), we'd expect a 1.5cm missile to be 1/10000 tons and deal around 2.5d dDamage at 1 mile per second (1760 yards/sec). Gyrocs are about half that weight and deal around 1/4 the damage. If we assume the reduced weight is due more to having less propellant than having a smaller payload, that implies a velocity of around 440 yards/sec, on the low end of rifles. Which, honestly, doesn't seem too bad. I'd probably bump it up to 500 (on par with the IML and similar). Next up is the cost of micromissiles when compared to smart bullets. Normal gyrocs already have most of what a micromissile needs (adjustable flight surfaces, which they need to rely on for stability) and mostly just need a guidance system, while normal bullets lack any such. It may be appropriate to reverse the relationship, with smart bullets having a base cost of 10x the cost of normal bullets and gyrocs being micromissiles by default. Personally, I'm inclined to go with 10x for smart bullets, 2x for micromissiles (so base of $10 instead of $50), and make guidance systems be a flat additional cost (there's no reason a skill 14 guidance system for a 15mm projectile wouldn't work installed in a 64mm projectile, provided the software was adjusted properly); higher cost systems should also be available for a higher price, but that's a digression. Finally, there's the oddity of lacking a 1/2D range - apparently, the bullet just stops once it runs out of fuel, rather than continuing on a natural ballistic trajectory. HT has +P give the same boost to damage and range, and UT has ETC do the same. Applying this same concept to the 15mm Magnum pistol -> 15mm gyroc -> 15mm antimateriel rifle/Heavy Chaingun, the gyroc is x1.4 to damage compared to the pistol round, x0.4 to damage compared to the rifle round. Applying the same to range, we get 329/3640 converting from the pistol, 800/3600 converting from the rifle. The gyroc's aspect ratio is probably closer to that of a rifle bullet than that of a pistol, but probably not by a lot; I'd call it 600/3600. That means the gyroc has a velocity of 500, has a flat trajectory (+2 to hit) out to 1900, has a 1/2D of 2500 (1900+600), and a Max of 5500 (1900+3600). With all that out of the way, let's explore some potential additional options for gyrocs. Skip down to tl;dr for statistics without discussion. Hot Gyroc: This is a gyroc designed to burn through its fuel at a greater rate, in order to achieve a higher velocity. Looking at things simplistically (which is probably wrong, as we're supersonic, but it's the best I can do), GURPS damage scales linearly with velocity, while the power required scales with the square of velocity. A 9d pi++ gyroc would have move 750, but would burn through fuel at 2.25x the normal rate, running out in 1.69 seconds instead of 3.8 seconds, so it would only travel around 1250 yards in that time (giving it Range 1850/3850). You need a more robust engine to manage the increased output - I'd say multiply CPS by the cube of the damage boost. The best you can manage is x2 speed, for move 1000, flat trajectory out to 950, Range 1550/3550, and x8 cost. TL 10: Better propellants allow you to run "hot" by default. A baseline TL 10 gyroc is 9d pi++, move 750, has a flat trajectory out to 2850, and has Range 3450/6450. This is extrapolated from the way missile launchers work; one could continue the progression, for x2 at TL 11 and x3 at TL 12. Long Gyroc: This is a longer gyroc, with more fuel for a longer burn. If we assume a gyroc's payload is a 15mm sphere of lead, it would weigh 20 g out of the total of 45 g of a gyroc. Sadly, nothing TL9 in Spaceships has sufficient performance to reach Move 500 within 10 yards, but if we assume roughly 50% of the remaining weight is the rocket engine and 50% is the fuel, that means around 12.5 g of fuel (a 27.8% mass fraction) gets us to 1900 yards before it runs out. Cribbing from the simplified rocket equation calculations from Spaceships - and rounding up to 30% - this implies every 5% of mass that is fuel would give around 265 yards (prior to rocket equation adjustments). A 15mm gyroc round is assumed to be able to fit in the grip of a pistol, but how long would it be? If we assume the fuel+casing and rocket are equal in density, and about half as dense as the payload, a 15mm wide cylinder weighing 25 g would be around 22.5 mm, for a total length around 37.5 mm. I think the general rule of thumb for something comfortable to grip in the hand is around 1" of width, or about 25 mm - the gyroc length is already far enough beyond this by the above simplistic calculations I think it's safe to say the grip is around the maximum one can comfortably handle. That in mind, Long Gyrocs probably have to be loaded elsewhere than the grip; a bullpup configuration may make the most sense. A double-length gyroc is probably around the largest such a round can get. With a 20g payload and 11.5g rocket (remember, we rounded fuel up to 30%), and 1.11g/mm for case+propellant, we're looking at maximum of 55g propellant in a 86.5g rocket, or around 65%. That's good for 3445 yards before rocket equation adjustments, or around 5500 after. This would be a 0.2 lb gyroc. The rocket is probably the most expensive part of a standard gyroc, so set price to x1.5 or so. Other sizes: Gyrocs of other sizes are fairly easy to work out - assuming the rocket scales fine with size (which admittedly may not be the case), velocity/flat range stays the same, damage scales linearly with caliber, and weight/cost scales with the cube of caliber. I'll leave it up to others to come up with the stats for launchers. tl;dr: Note I've rounded some values to make things a bit more presentable Standard Gyroc: 6d pi++, range 2500/5500. +2 to hit within 2000 yards if not using rangefinder. 0.1 lb, $5 Micromissile: Must have Guidance Package (see below). Range standard for gyroc; Move 500. No range penalty (Guided/Homing). x2 CPS plus cost of Guidance Package (see below). Smart Bullet: Must have Guidance Package; unavailable for gyroc. Range standard for weapon; Move 300 for pistols, 600 for rifles (x1.5 for ETC). No range penalty (Guided/Homing). x10 CPS, plus cost of Guidance Package. Skill (6+TL). Guidance Package: Required for Micromissiles/Smart Bullets. May be Guided, Viper, Multi-Spectral, or Multiscanner. See UT146 for the last three. Guided: Requires user to maintain "lock" on target until impact, but uses user's skill. $50. Viper (TL9): $150 Multi-spectral (TL10): $500 Multiscanner (TL^): $500 TL 10: At TL 10, the standard gyroc improves to 9d pi++, velocity 750, flat range 2850, range 3450/6450. Optionally, boost to 12d pi++, 1000, 3800, 4400/7400 at TL 11, 18d pi++, 1500, 5700, 6300/9300 at TL 12. No change in WPS/CPS. Hot Gyroc: x1.5 to damage is x1.5 to velocity, x0.7 to flat range. x3 CPS. x2 to damage is x2 to velocity, x0.5 to flat range. x8 CPS. Flight Gyroc: Not generally available for gyroc pistols (requires loading individually, or with a bullpup configuration). Hot and Flight are often combined and offset each other. (Changed the name because Hot Long Gyroc sounded... yeah). x1.5 flat range is x1.2 WPS and x1.1 CPS. x2 to flat range is x1.5 WPS and x1.2 CPS. x3 to flat range is x2 WPS and x1.5 CPS. Reactionless (TL^): Replaces fuel with an energy bank and rocket with reactionless thruster. Standard is x5 to flat range and x2 CPS; can be combined with Hot and Flight. Other sizes: Note, TL is just a suggestion (it assumes gyrocs are one size category less finicky than the Viper guidance package); additionally, damage is listed as for TL 9, regardless of actual TL. Largest caliber is 40mm as 64mm is an IML. Code: TL Cal Damage WPS(lb) CPS($) 9 40mm 15d pi++ 2 100 9 25mm 10d pi++ 0.5 25 9 18.5mm 7d pi++ 0.2 10 9 15mm 6d pi++ 0.1 $5 9 10mm 4d pi+ 0.03 1.5 10 7mm 3d pi 0.01 0.5 11 5mm 2d pi 0.003 0.15 12 3mm 1d+2 pi- 0.001 0.05 So... thoughts? Does this look like it would make gyrocs a bit more usable? __________________ GURPS Overhaul