11-02-2016, 11:39 AM | #11 | |
Join Date: Aug 2004
Location: Binghamton, NY, USA. Near the river Styx in the 5th Circle.
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Re: Approximating High-Tech and Ultra-Tech with Spaceships
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GURPS Spaceships, p. 35, lists how to get Air Performance figures, including vehicle speed. Turbofans have a maximum air speed of 2,000mph (see p. 10 of Spaceships 7). Here's my workup of the design using my spreadsheet.
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Eric B. Smith GURPS Data File Coordinator GURPSLand I shall pull the pin from this healing grenade and... Kaboom-baya. Last edited by ericbsmith; 11-02-2016 at 11:51 AM. |
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11-02-2016, 11:41 AM | #12 |
Join Date: Aug 2004
Location: Binghamton, NY, USA. Near the river Styx in the 5th Circle.
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Re: Approximating High-Tech and Ultra-Tech with Spaceships
F-15 'EAGLE'
PILOTING/TL7 (HIGH-PERFORMANCE AIRPLANE) Page: Code:
TL Name dST/dHP Hnd/SR HT Move LWt. Load SM Occ dDR Range Cost 7 F-15 'Eagle' 20 — 12 — 30 0.2 [1] +5 2SV [2] 0/5/0 — $3.075M Air Performance #1: aAccel: 1G (22 mph/s) aSpeed: 2,000 mph Hnd/SR: +5/4 Air Performance #2: aAccel: 1.5Gs (33 mph/s) aSpeed: 2,000 mph Hnd/SR: +5/4 SHIP SYSTEMS Code:
FRONT [1-3] Defensive ECM -6 to Hit [4] Tactical Comm/Sensor Array Array level: 3 [5] Major Battery one fixed mount 2.5cm improved very rapid fire conventional gun [6] Medium Battery three fixed mount 16cm missile launchers Code:
CENTER [1-5] Light Alloy Armor dDR 5 [6, Core] Control Room Comp: C0 / Comm/Sensor: 1 / 2 Stations Code:
REAR [1-2] Maneuver Enhancement +2 Handling [3-4] Afterburning Turbofan 1 G / 1.5 Gs & 4x Fuel Use / 1.5 hr Fuel [3,4,5] [5-6, Core] Fuel Tank 4.5 Tons of Jet Fuel SHIP OPTIONS: Streamlined, Winged, Emergency Ejection Pod [1] Load includes: 0.2 tons of Crew & Passengers [2] Crew Requirement: 2 Control Stations (1 Pilot, 1 Navigator) PERFORMANCE PROFILES: [3] Air #1, [4] Air #2 FUEL USED: [5] Jet Fuel (4.5 tons) TROOP STRENGTH (TS): (217) CLASSES: Air FEATURES: Night, Sealed WEAPONS TABLE Range Scale: Basic Combat Ranges Turn Length: 20-sec Code:
Qty. Location Weapon Mount Options Size Damage sAcc [1] Rcl RoF Shots MPS Accel Projectile Range SM 1 Front [5] - Major Conventional Gun Fixed Very Rapid Fire 2.5cm 3d+2 (2) cr -8 (+8) [2] 3 200 [4] 1,400 1 -8 C 3 Front [6] - Medium Missile Launcher Fixed 16cm 6dx4 (2) cr +1 [2] 1 3 [3] 15 6 6G -1 X Created using the GURPS Spaceship Design Spreadsheet Version 2.0 RC 13 based on the GURPS Spaceships series of books. http://gurpsland.no-ip.org/#GURPSSpa...ignSpreadsheet
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Eric B. Smith GURPS Data File Coordinator GURPSLand I shall pull the pin from this healing grenade and... Kaboom-baya. Last edited by ericbsmith; 11-02-2016 at 01:37 PM. |
11-02-2016, 11:51 AM | #13 | ||
Join Date: May 2010
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Re: Approximating High-Tech and Ultra-Tech with Spaceships
Quote:
Quote:
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11-02-2016, 12:04 PM | #14 |
Join Date: Feb 2005
Location: Berkeley, CA
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Re: Approximating High-Tech and Ultra-Tech with Spaceships
Note that the listed performance is divorced from reality, as it discounts SM completely.
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11-02-2016, 12:07 PM | #15 |
Join Date: Aug 2004
Location: Binghamton, NY, USA. Near the river Styx in the 5th Circle.
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Re: Approximating High-Tech and Ultra-Tech with Spaceships
Armor/Volume rule only takes it from dDR 5 to dDR6, since five units of armor doesn't significantly increase dDR. If using my optional rules for partial dDR a SM+5 streamlined ship would qualify for dDR 1.5 each, giving dDR 7.5 for five systems of Light Alloy, and a final dDR 9 after adding them together and multiplying for Armor/Volume.
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Eric B. Smith GURPS Data File Coordinator GURPSLand I shall pull the pin from this healing grenade and... Kaboom-baya. |
11-02-2016, 12:40 PM | #16 |
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Re: Approximating High-Tech and Ultra-Tech with Spaceships
How SHOULD SM effect top speed? I'm not seeing any particular reason why it should.
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11-02-2016, 01:07 PM | #17 |
Join Date: Aug 2004
Location: Binghamton, NY, USA. Near the river Styx in the 5th Circle.
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Re: Approximating High-Tech and Ultra-Tech with Spaceships
The bigger the SM the smaller the front cross-section so the smaller the surface area that's exposed causing drag, which should allow larger ships to go faster given similar other stats (thrust to mass, etc).
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Eric B. Smith GURPS Data File Coordinator GURPSLand I shall pull the pin from this healing grenade and... Kaboom-baya. |
11-02-2016, 01:09 PM | #18 |
Join Date: Feb 2005
Location: Berkeley, CA
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Re: Approximating High-Tech and Ultra-Tech with Spaceships
Drag scales with surface area (second power of linear scale), thrust at any given acceleration scales with mass (third power of linear scale). Max speed is the speed at which drag is equal to thrust. Thus, on average you want to multiply top speed by the square root of linear scale.
There are other limiting factors -- notably, air-breathing engines have variable thrust depending on velocity, and stagnation temperature of air exceeds the melting point of aluminum at a bit under mach 3, iron at around mach 4, and any known materials by mach 6, which limits speed by what your hull is made out of. Last edited by Anthony; 11-02-2016 at 01:17 PM. |
11-02-2016, 01:41 PM | #19 |
Join Date: Dec 2007
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Re: Approximating High-Tech and Ultra-Tech with Spaceships
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11-02-2016, 01:49 PM | #20 |
Join Date: Aug 2004
Location: Binghamton, NY, USA. Near the river Styx in the 5th Circle.
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Re: Approximating High-Tech and Ultra-Tech with Spaceships
No, but it does to F-15's and most other flying planes and spaceships (which is what we started talking about in post #8 or so).
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Eric B. Smith GURPS Data File Coordinator GURPSLand I shall pull the pin from this healing grenade and... Kaboom-baya. |
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