06-24-2013, 09:59 AM | #1 |
Join Date: Aug 2004
Location: Hamilton, Ont. CANADA
|
[Spaceships] Homebrew - Alternate Contragrav
Another new design switch suggestion for GURPS Spaceships:
Force Screen Variant Gravity Screen: Provides no DR (although it does affect Tractor Beams[1] and Graviton Guns[2]) but instead lessens the gravitational effect of outside masses on the ship. Read "dDR" as the divisor applied to a planet's gravity to determine its effect on the ship*. You can have both a gravity screen and another force screen. * The ship's mass remains the same however, so the rate of ascent in a vertical take-off would be A-G/dDR where A is the spacecraft’s drive acceleration in G, G is the world’s gravity and dDR is the gravity divisor. To find the effective escape velocity of planet while using the screen, divide its natural escape velocity by the square root of the dDR. (FWIW: The solar escape velocity from a planet's orbit is that planet's mean orbital velocity times sqrt(2).) Example: An SM+10 (10,000 ton) ship with a gravity screen installed has an effective weight of 66 2/3 tons on a 1G planet. If that planet is Earth, its effective Ve would be 6.96/sqrt(150)=0.568 mps.While not a defensive system, the gravity screen does have an effect on gravity-based weapons:
Dalton "treating this with the appropriate gravity" Spence
|
06-24-2013, 12:06 PM | #2 |
Join Date: Apr 2005
Location: Houston, TX
|
Re: [Spaceships] Homebrew - Alternate Contragrav
Should it be a high-powered component?
(Not with my books, so I don't remember whether that's already true of force screens.) |
06-24-2013, 12:24 PM | #3 |
Join Date: Jun 2006
Location: On the road again...
|
Re: [Spaceships] Homebrew - Alternate Contragrav
Yes, force screens are already high-powered components.
__________________
"Life ... is an Oreo cookie." - J'onn J'onzz, 1991 "But mom, I don't wanna go back in the dungeon!" The GURPS Marvel Universe Reboot Project A-G, H-R, and S-Z, and its not-a-wiki-really web adaptation. Ranoc, a Muskets-and-Magery Renaissance Fantasy Setting |
06-24-2013, 12:31 PM | #4 |
Join Date: Feb 2005
Location: Berkeley, CA
|
Re: [Spaceships] Homebrew - Alternate Contragrav
Why is it a force screen variant? It's just a contragravity variant, and there's no reason the effect would scale with the size of the ship.
|
06-24-2013, 12:42 PM | #5 | |
Hero of Democracy
Join Date: Mar 2012
Location: far from the ocean
|
Re: [Spaceships] Homebrew - Alternate Contragrav
Quote:
As for why it scales in size, the generator seems to effect things not based on the mass of what it effects, but a large area determined by the size of the generator. That said, In a setting with this, I'd probably get a 1/3 or 1/10 one for my ship, because there is very little punishment for going undersized unless graviton beams are a dime a dozen. Its very effective at any size.
__________________
Be helpful, not pedantic Worlds Beyond Earth -- my blog Check out the PbP forum! If you don't see a game you'd like, ask me about making one! |
|
06-29-2013, 10:59 AM | #6 |
Join Date: Aug 2004
Location: Hamilton, Ont. CANADA
|
Re: [Spaceships] Homebrew - Alternate Contragrav
FWIW, I worked out the effect of the Gravity screen on effective escape velocities (and thus orbital ones). Multiply the velocity by the modifier below.
Code:
Escape Velocity Modifier SM TL11^ TL12^ +4 0.25820 0.22361 +5 0.22361 0.18257 +6 0.18257 0.14142 +7 0.14142 0.11952 +8 0.11952 0.10000 +9 0.10000 0.08165 +10 0.08165 0.07071 +11 0.07071 0.05774 +12 0.05774 0.04472 +13 0.04472 0.03780 +14 0.03780 0.03162 +15 0.03162 0.02582 Dalton “who didn't get his birthday card from the Illuminati” Spence
|
06-29-2013, 12:01 PM | #7 |
Join Date: Dec 2007
|
Re: [Spaceships] Homebrew - Alternate Contragrav
Against a weapon nobody would use considering that this would be a standard propulsion system if available. Actually I'd suggest making it effective against missiles as well, but not beam weapons.
|
06-29-2013, 04:04 PM | #8 |
Untagged
Join Date: Oct 2004
Location: Forest Grove, Beaverton, Oregon
|
Re: [Spaceships] Homebrew - Alternate Contragrav
Just curious, but what would be your in game reasoning / techno-babble as light is just as effected by gravity as matter?
__________________
Beware, poor communication skills. No offense intended. If offended, it just means that I failed my writing skill check. |
06-29-2013, 05:35 PM | #9 |
Join Date: Feb 2005
Location: Berkeley, CA
|
Re: [Spaceships] Homebrew - Alternate Contragrav
Well, sort of. Gravity is generally more relevant to slow objects. A lot of 'gravity'-based drive systems are likely to have boundary conditions that would be problematic for low velocity projectiles, though I'm not sure why this particular system would.
|
06-29-2013, 06:26 PM | #10 |
Join Date: Dec 2007
|
Re: [Spaceships] Homebrew - Alternate Contragrav
|
Tags |
spaceships |
|
|