________________________________________ GURPS Vehicles 2nd Edition Additions MA Lloyd (malloy00@io.com) 9 August 1998 Modifications and Additions to Chapter 1: Vehicle Design ________________________________________ This chapter really tries to do too much at once. Most of Part V should have been in the Surface Features chapter, and I might have placed Part IV just before that as a separate chapter so the design process flowed straight through rather than in and out of Chapter 1. ________________________________________ p4* Calculations. The cube root table is on p 138. p4 Metric and Other Conversions. Change the table entry to 1 pound (mass). Add 1 pound (force or thrust) = 4.45 Newtons. p7 Heavy Wheels. Add the clarification 'the increased wheel area lowers the vehicle's ground pressure'. p8* Rotors. The line "Select one of these rotor types for the vehicle." should read "Select an autogyro rotor (TL6) or one of these types of helicopter rotor:" p11 Streamlining. A vehicle with cycle seats or stations, external seats or external standing room cannot have better than fair streamlining. p12* Aerostatic Lift. Lift fans are TL7. p14* Power Systems. Reference should be to p81, not 91. p16 Body Volume. Mecha allows body volume to simply be larger than any attached subassembly, not necessarily larger than the total of all of them. There are other plausible exceptions to this rule as well. p17* Wing Volume. Stub Wings should be 0.02 x body volume. p17 Stub Wings. Stub wings may have any volume. Treat them as part of the body when computing lift, aMR and so on, and do not require the Wings cost multiplier. p18 Structures. Robotic Structure does not exist. A robotic brain requires no special data pathways not equally necessary for a non-robotic control system of equal capability. p18 Structures. Living Metal can't repair ablated armor or totally destroyed systems without a source of mass. A weight of $1/lb 'damage control paste' equal to the lost weight must be applied before the repair begins. p18 Biomechanical and Living Metal Structures. Instead of a flat 1 hit point per time unit, the GM may want to set the healing rate at 5 or 10% of original hit points per time unit. p19* Vehicle Structure Table. Extra Light cost is x 0.25. p19 Vehicle Structure Table. Any vehicle with aerodynamic or hydrodynamic lift must have either the Lifting Body or the Wings/Rotors option. p20 Weight and Cost of Masts, Open Mounts and Gasbags. The Materials and Special Structure multipliers from the Vehicle Structure Table (p19) may also be applied to the weights and costs of masts and open mounts. p20* Gasbag Weight and Cost Table. The weight multipliers for TLs 5-, 6, 7, and 8 should be 0.012, 0.008, 0.006, and 0.004. p20 Gasbag Weight and Cost Table: 5- 0.036 $0.3 9 0.009 $1.0 6 0.024 $0.5 10 0.006 $1.0 7 0.018 $1.0 11 0.004 $1.0 8 0.012 $1.0 12+ 0.003 $1.0 Add: A balloon folded for transport occupies weight/40 cubic feet. p20* Hit Points. Optionally see p183 for component Hit Points. p21* Wing and Rotor Options. Variable Sweep wings should cross-reference p160. p21* Armor. Metal Armor is TL1, not TL5. p22 Armor. The rows Nonrigid TL6- and TL7+ should read Solid and Open Weave respectively. Solid armor DR is not reduced against impaling weapons, but open weave is, to DR1 at TL7, DR2 at TL8 or 9, and DR5 at TL10+. p22* Ablative Armor. Car Wars armor is expensive, not standard. p22* Armor Table. The multiplier for TL8 Cheap Metal armor is 0.5, not 0.25. p22 Selecting Armor. A vehicle with streamlining, slope, flotation, a sealed body or a submersible hull needs at least DR1 from something other than open frame armor. Vehicles must have DR5 to exceed 600 mph, DR20 to exceed 2000 mph, and substantial armor to survive reentry (p164). p25 Vision. Thick glass can be surprisingly tough. Maximum DR is 5 at TL5 and below, 15 at TL6, 25 at TL7, 35 at TL8 and unlimited thereafter. p26 Weight and Mass Statistics. If the vehicle has a cargo carrying top deck, the cargo weight is added to loaded weight. This can be anything up to 300 lb. per sf of deck area. ________________________________________ Vehicle Design p7a Skids ________________________________________ A vehicle with no underside subassemblies and DR of 5 or more there may use the entire underside as a skid. No skid subassembly is required. Performance is as skids, except ground pressure contact area is body surface area/10. ________________________________________ Vehicle Design p7a Wheels ________________________________________ The free design of wheels can be allowed with some fairly minor changes: p7 Wheels. Replace with: Wheels allow a vehicle to roll along the ground. A single wheel subassembly includes all the vehicle's wheels and axles, plus any tires, steering, suspension or braking systems; but not the drivetrain, if any. Any number of wheels may be selected. Additional wheels reduce maneuverability in exchange for stability and greater contact area. Wheels are faster and more efficient than skids or legs, but are less able to cross some types of terrain. p17 Volume of Other Subassemblies *Wheels* Choose a volume, typically about 0.1 x body volume, but anything from 0.02 to 1.0 x body volume is possible. If the volume is less than 0.01 x number of wheels x body volume, the wheels count as 'small wheels' limiting gMR (p129) and off road movement (p130). p17 Surface Area *Wheels* Find the area of each wheel separately - that is divide the total volume by the number of wheels, compute an area from that, and multiply by the total number of wheels. This is equivalent to the standard formula times the cube root of the number of wheels. p21 Wheel Options. Two specialized wheel types become wheel options: *Railway Wheels* (TL5) engage a particular type of track allowing travel at higher speeds, but only while the vehicle remains on the track. Railway wheels are designed as normal wheels, but have a higher speed factor and no off-track performance. They are limited to one kind of track; monorails and cars suspended from overhead rails are the most obvious variants, but something as simple as changing the track width makes a railroad impassable. *Off Road Wheels* (TL6) are built for cross-country travel, with unusually high suspensions and heavier tire designs. This adds $20 x wheel surface area to the cost. Small wheels may not take the Off-Road option. _____________________________ Vehicle Design p10a Submersible Hull _____________________________ The submersible hull option combines structural reinforcement to handle depth pressure and extra volume for ballast tanks. These should be separated, since it is possible to design a submarine with active flotation or hydrodynamic lift rather than ballast tanks. The structural option (p19) is optional for submersibles, but increases crush depth. Drop the volume multiplier (p16) and add: Ballast Tanks (TL5): are spaces that can be filled with water or air to alter the vehicle's weight. To design them simply add the volume desired to the vehicle volume, increasing flotation when the tanks are dry. When the tanks are flooded, add up to 62.5 lbs. x their volume to Lwt. If that still doesn't exceed flotation the vehicle can't submerge. Traditionally this is fixed by adding tanks of mercury (see p89a), which have the advantage they can be dumped to reduce Lwt. in an emergency, but adding extra armor works too. The existing rules are equivalent to ballast tanks equal to 25% of the original volume of the vehicle. ________________________________________ Vehicle Design p11a Pontoons ________________________________________ Some light vehicles, notably seaplanes, float entirely on pontoons. Build these as pod subassemblies with sealed hulls. If the flotation of the pontoon alone (62.5 lb. x pod volume) is enough to float the vehicle, only the areas, volumes and hydrodynamic lines of the pontoons influence water performance. ________________________________________ Vehicle Design p15a Cargo Space ________________________________________ *Refrigerated Cargo* (TL5): Some or all of a vehicle's cargo space can be refrigerated. This uses up 2% of the space for insulation and refrigeration coils, costs $1 per cf cooled and consumes 0.005 kW per cf. ________________________________________ Vehicle Design p16a Retractable Subassemblies ________________________________________ Wheels, skids, hydrofoils, wings, arms and perhaps other subassemblies can be designed to retract, usually for better streamlining. Retraction space equal to 1.2 times the unretracted volume must be allocated as a component in the location retracted into. For assemblies with volume depending on the body volume you can avoid design loops by multiplying the body volume by 1 + (1.2 x usual body fraction) for assemblies that retract entirely into the body, 1 + (1.2 x fraction/3) for assemblies that retract into the body and two wings etc. [This does change the volume multipliers for retractable wheels and skids, to better agree with the other retractable component in GURPS. Use 1.5 rather than 1.2 to preserve the original statistics]. ________________________________________ Vehicle Design p18a Flotation Streamlining and Surface Area ________________________________________ Flotation, streamlining and related topics are not handled correctly, the real effect is to increase surface area, not to add fake volume. Nearly the same results can be obtained more logically with a fairly simple set of alterations: p10 Hydrodynamic Hulls. Paragraph 4, change 'less usable volume' to 'greater surface area'. p11 Hydrodynamic Hull Effects on Flotation. Drop this paragraph entirely - all hulls get 62.5 lb. per sf. p11 Slope. Change Paragraph 6 to begin 'The disadvantage of slope is it adds to surface area. However, if the vehicle is to be heavily armored...' p15 Turret Volume. Drop the second paragraph, slope has no effect on volume. p16 Arm Superstructure and Pod Volume. Paragraph 1. Drop slope references. p16 Body Volume. Drop all the multipliers except Submersible Hull and Retractable Wheels/Skids (and see p10a and p16a for suggestions on replacing them as well). p18 Surface Area Add 'The surface area of the body or subassemblies is increased by certain features: *Catamaran Hull*: multiply body area by 1.5 *Trimaran Hull*: multiply body area by 2.0 *Hydrodynamic Hull*: multiply by 1.066 for Mediocre lines, 1.13 for Average or Submarine lines, 1.19 for Fine or Very Fine lines. A vehicle with Good or better streamlining can be considered to have Mediocre lines for free should it enter the water. *Streamlining*: multiply by 1.066 if Fair, 1.13 if Good, 1.16 if Very Good, 1.19 if Superior, 1.222 if Excellent, and 1.251 if Radical. *Slope*: sum the slope angles on all the faces of the turret or body and multiply the area of the sloped structure by 1.066 if it is 30 degrees or less, 1.160 if 60 degrees, 1.25 if 90 degrees, 1.37 if 120 degrees, 1.59 if 150 degrees, 1.84 if 180 degrees, 2.22 if 210 degrees, and 2.92 if 240 degrees. ________________________________________ Vehicle Design p18a Structural Options ________________________________________ Modular Structures (TL6): The vehicle is designed to break down for easy transport. It requires 0.01 man hours x number of modules x vehicle size modifier to assemble or disassemble on a successful Mechanic +2 roll. Failure wastes the same amount of time, critical failure damages something important. Mutable Structure (TL8): The vehicle can reconfigure its surface and structure to change its appearance. Normally this alters the apparent make or model, but it can make the vehicle look like any similarly shaped object. A mutable structure can add up to 10% to the apparent volume of the vehicle and reduce streamlining by any amount. Modular x1.1 x4 Mutable x1 x1.2 ________________________________________ Vehicle Design p21a Wing Options ________________________________________ Tailless (TL7): Wings normally include a tail, a winged vehicle with this option lacks the tail and tail control surfaces. Multiply the structural cost by 1.5, subtract 2 from the radar size modifier, subtract 1 from aSR and 1 from TL when computing aMR. Most such craft will also have the Controlled Instability option, but it isn't required. ________________________________________ Vehicle Design p24a Waterproofing and Sealing ________________________________________ Self Sealing Hull (TL6): For double cost and an additional 0.2 lb/sf (at TL6, half weight at TL7, quarter it at TL8+) a sealed hull may be self sealing. A Self Sealing Hull will close small punctures in less than a second. The GM may declare major breaches beyond the ability of the hull, and small punctures may eventually leak in corrosive atmospheres as the corrosive destroys the sealant, but ordinary leaks and flooding are prevented. ________________________________________ Vehicle Design p24a Sealed Sections ________________________________________ It is sometimes desirable to seal sections of a vehicle from each other - to contain hazardous cargo, for medical isolation, or just to maintain life support for two species that breathe different gases. Simply determine the volume of the sealed area, find its surface area, and buy a separate sealed hull for it. Sealed hatches between sections are free, but internal airlocks must be added to allow passage without compromising the seal. ________________________________________ Vehicle Design p27a Appendix ________________________________________ Hardened Electronics Any electronic component can be built to survive electrical disruption. Hardened electronics are immune to electromagnetic pulse, line surges or radiation damage. Lighting strikes, paralysis beams, short circuits and other disasters simply blow fuses or open breakers; the component can be returned to normal operation in under a minute. Hardened electronics have 5 times the cost and three times the weight and volume of normal electronics. Prior to TL7 most devices are *automatically* immune to EMP, paralysis beams and other attacks that short out sensitive electronic components. The tube technologies from Lensmen are similarly resistant. Component Structures Several of the options available for vehicle structures (p19) can be added to individual components - particularly Biomechanical, Living Metal and the materials costs options. Note however that components designed for high stress environments (engines, drivetrains, power plants, gun barrels and so on) or anything already described as lightweight, compact or high performance should be assumed to already be made of Expensive materials, and that downgrading to anything less than Standard (effectively x1.33 weight, x0.5 cost) is justification for any bugs or disasters the GM wishes to inflict on the hapless designer.