Low-Tech maneuver drives

[Bob Weaver]

Hey gang,
I'm working on an idea for an isolated low-tech planetary system (TL 7) that has space flight but not jump drives. I know HG2 (I use only Bk2 and Bk5) has TL7 drives, but I want a bit more detail. I'd like to model chemical rockets or other non-gravitic propulsion, but my astrophysics knowledge is lacking. Does anyone know of design rules or tables for low-end drives like this? One of my big questions is the fuel requirements, which I'm sure would be much different from fusion plants. Also any thoughts on how this might affect combat damage? Surely a solid O2 fuel tank would react very badly to a laser beam hit. I'm open to advice and suggestions. Thanks for your help.

Best Regards,
Bob Weaver

 

[Fritz_Brown]

Bob, have you looked at Fire, Fusion & Steel? It is full of the kind of thing you're looking for. It is VERY gearheady, but it covers loads of variants for propulsion. I went to DrivethruRPG, and grabbed both versions - TNE (Technical Architecture) and T4 (Revised).

 

[mike wightman]

I would also recommend HardTimes, a MegaTraveller supplement which has rules for pre-gravitic spaceflight and ship design.

 

[Rossoneill]

You could use Fire Fusion and steel but its not Ct its more like Megatraveller .
You could adapt it though .

 

[Rossoneill]

You could use Fire Fusion and steel but its not Ct its more like Megatraveller .
You could adapt it though .

 

[daryen]

In the interests of completeness, you can also take a look at GURPS Traveller: Starships.

It does use a different TL scale, but gives many options for maneuver propulsion.

 

[aramis]

Wood, Wind, Fire and Steam (Chalenge article) adds a lot more options for MT designs, as does HT; WWF&S is probably TOO low tech for your purposes, but HT is just right TL wise.

FF&S 1&2 both have a variety, as well; essentially, the same selection as HT for the TL range.

There is really no CT detail past what's given. Assume either a thermal rocket or some form of plasma rocket and you're fairly safe. Or, just assume out -2TL's of gravitics is why we, at TL8, lack gravitics.

 

[Uncle Bob]

Google on "celestial mechanics". I have yet to see a game book (including FF&S) worth warm spit when it comes to reaction drives.

The other important rule is the "Rocket Equation"
Vd = Ve * ln(Mi/Mf)

Vd change in velocity for the burn
Ve Exhaust velocit
Mi initial mass
Mf mass after the burn

ln natural log

 

[Jeff M. Hopper]

http://www.travellerrpg.com/cgi-bin/catalog/pview.pl?action=view&stocknum=3rdave0006&h=10&s=

Golden Age Starships #3 has got a good cover for TL 7 maneuver drives. I just downloaded it and love it. I don't know why they have not been advertising this more.

 

[barfoo]

Chemical rockets are way too low performing. Nuclear fission drives is probably what you want for realism/useability. We (RealWorld) built one in the sixties and had it running in testbed on ground but it was scrapped for whatever reason. With fission drives you can have the TL 7 guys doing trips equivalent to Mars and generally behave like rockets should.
http://www.projectrho.com/rocket/index.html

 

[barfoo]

Can anybody say anything about the quality of the deckplans ion Golden Age Starships #3?
Are they on par with GDW Traders and Gunboats or what?

 

[mike wightman]

Originally posted by Backman:
Can anybody say anything about the quality of the deckplans ion Golden Age Starships #3?
Are they on par with GDW Traders and Gunboats or what?

Yep, the quality is really good IMHO.

And welcome aboard Backman

 

[mike wightman]

Originally posted by Backman:
Chemical rockets are way too low performing. Nuclear fission drives is probably what you want for realism/useability. We (RealWorld) built one in the sixties and had it running in testbed on ground but it was scrapped for whatever reason. With fission drives you can have the TL 7 guys doing trips equivalent to Mars and generally behave like rockets should.

Have you seen this yet?

 

[mike wightman]

This may be of interest too.

 

[Uncle Bob]

Ah, Sigg, a blast from the past. Daedelus, NERVA, the F1, the Good Old Days. The Skylon is a lot of wishful thinking, though.

That NERVA/Mars ship was the first one I studied seriously when it first came out in ... 1968? I had just finished doing deckplans of the ships from "2001: A Space Odessey" and was looking for something RW.

 

[Jeff M. Hopper]

In the BITS publication 101 Starships for GT, there is a section in the back detailing ORION type propulsion systems. Its all really good stuff.

 

[parmasson]

This may not be timely enough to be useful but GURPS Traveller Starships on pgs.37-38 gives some info on different types of drives.

 

[Bob Weaver]

Guys,
Thanks for all your input. It's probably going to take me a while to sift through all the suggestions, but I'm sure I'll come up with something usable in the end. Many thanks, indeed to you fine folk.

Bob Weaver

 

[Sifu Blackirish]

IMTU I decided not to hgive humans gravitics, instead opting for a high efficiency ion system.

I use the same Book 2 values for size, just chopped the acceleration to 10% of actual.

I figured that a high efficiency ion propulsion system could be justified with just a little handwaving...

 

[Ptah]

DLO

IMTU I decided not to hgive humans gravitics, instead opting for a high efficiency ion system.

I use the same Book 2 values for size, just chopped the acceleration to 10% of actual.

I figured that a high efficiency ion propulsion system could be justified with just a little handwaving...

Browsing through past posts...this one caught my eye. Here's a good link on current ion engine technology.

http://nmp.jpl.nasa.gov/ds1/tech/ionpropfaq.html

Down the page you'll note a comparison between chemical and ion drives. One key "application" for which rapid acceleration is needed, is getting people into orbit. You really don't want to be in the radiation belts too long. As you'll see, the science supports having ion drives at TL7. I'd imagine you would have chemical drives to get people into orbit. Ion drives wuold be used to traverse the solar system. I'm not sure if Xenon could be found on the rocky bodies, but I think it exists in the gas giants. The beginning of fuel skimming!

A big fan of ion drives 'since was one of the guys at the AFOSR that did some of the research to help get these going. Xenon is the fuel of choice for several reasons, one big one is it's mass.

One idea on further development of "ion drive" technology, is coulomb explosion drives. More on this later. I'll also check my CRC on the gas giant thing.