Reaction Drive questions

[GamerDude]

Deckplans for Traveller ships are all based on the ships gravity point being its belly, all those artificial gravity fields and inertial dampers allow for long thin decks and belly lander designs.

Reaction drive ships will be tail landers inthat thrust based gravity comes from the tail. This makes small decks stacked on top of each other more practical. Those long corridors down the length of the ship may be fine for grav drives but they turn into very deep drops under reaction drives. Think mercenary cruiser.

What? Maybe when using the old three or four finned rockets ships of the 40's and 50's... but who says they can't be um... streamlined and FLY in (um, space shuttle).

There was an show, with Andy Griffith, "Salvage 1"?, where he built his own rocket that took off and landed vertically. Had three engines in it. Amazingly they showed how hard it is to land the way you say and this was in the late 70's.

Now, of you can show even one ship that can land like that, I'd like to see it.
And that was landing on a planet with an atmosphere... winds pushing the ship about laterally, balancing the engines to come down straight not top over (where the imbalance could cause the thrust to flip the ship), you still need control surfaces and attitude jets (and I'm not sure they would work well enough or fast enough to compensate etc.)

Even without an atmosphere landing vertically is still a dangerous maneuver, just watch the video of any of the Apollo moon landings. Without spending a great deal of fuel canceling your horizontal velocity (what is keeping you in orbit) you don't just drop straight down (under near constant thrust counter the gravitational pull). So you are still moving laterally as well as vertically, with gravity pulling you down trying to accelerate your rate of fall as your engines fight to counter that on top of slowing you down.

((and yes, I read everything in both the MGT Core and High Guard books again before answing)

 

[zero]

@ Barnest2 - Thanks for that, I recognise the values but am struggling with the actual equation. If someone can tell me if the one that brought me to 17 minutes to T-Point is right or they can correct me, that'd be awesome.
Bear in mind my skill at math is of the average joe, I dont suck but Im no rocket scientist either (thus the topic :wink: :lol: ).

@ Captain Jonah - I generally design all my ships with Trav deckplans and seats and things being on gimbals and some floor panels having built-in ladders so in effect in can switch between tail-lander or belly-lander depending on the circumstance :wink: Lots of iris valves in corridoors mean potential drops off ladders wont be too far.
I even go so far as due to multi-G accel/deccel that controls for the ship are built into seat arms and allow for minimum movement whilst the terminals and comps etc are only displays, with no actual controls on.

So again, did I get the equation right, if not, what is the right equation to use for straight accel or deccel, not doing both (which I know)??? :roll:

 

[Captain Jonah]

Sorry if I was not clear. By tail Lander I am referring to ships where the decks are stacked on top of the next, my example being the mercenary cruise. I am not suggesting they actually land. It is an old reference to deck orientation.

Traveller ships are traditional belly Landers in that the decks are orientated along the belly such as the scout, free trader, far trader etc.

Since the gravity in a Traveller ship comes from the grav plates in the floor this isn’t a problem and you end up in a long low building type ship layout.
With a reaction drive your thrust produces gravity drag down towards the drive (the tail). In this case your ship if designed as a normal traveller one ends up standing on its side and all those long corridors down the ship become drops. With tail Lander designs (look at the mercenary cruiser) you have a series of decks that under and drive thrust are like the stories in a tall building (one on top of the other). Though people spend the transit acceleration in pods there are going to be many times when you will be operating under reaction thrust. Climbing a 3m ladder to the next deck at 1G on a tail Lander ship is someone different to going from engineering to the bridge up the 30m ladder that the main stem to stern corridor just became.

For example using 1G or more in combat the bridge is hanging some 10m, above sensor control, fire control is 30 odd metres above the spin ring and another 12m drop from there to the wall by the infirmary doors on the Knight. That is a heck of a long way to go with casualties or for damage control in the middle of a fight, of course you could simply cut thrust and drift to allow people to swim around in zero G if you don’t want to manoeuvre or evade that turn of the battle.
Even with Zeros lots of Iris valves it’s still a long climb with waits at the doors. Time counts in the middle of a disaster

 

[Sturn]

A few other things to consider for your ships Zero.

Deckplans for Traveller ships are all based on the ships gravity point being its belly, all those artificial gravity fields and inertial dampers allow for long thin decks and belly lander designs.

Reaction drive ships will be tail landers inthat thrust based gravity comes from the tail.

What the Captain is saying is that if their is no artificial gravity on board, "tail landers" will be common so crew members can receive gravity during flight from the movement of the ship itself under reaction drives.

I can imagine a setting where artificial gravity is possible, but reactionless starship MD's (away from a gravity well) are not yet feasible. This would allow for reaction drive ships with the classic ship layout of class Traveller using artificial gravity, intertial compensators, etc. This is exactly my thought for an ATU I've been tossing about.

 

[zero]

No, I understand. I design my ships with gimballed chairs etc, which if you can imagine shift between a tail-lander mode and belly-lander mode, depending on gravitational pull.

Whilst I make a deckplan based on the usual Trav birdseye view, I also plan it as a side-on view, as if its a tail-lander too. I dont have a scanner to show, but I generally like to put little pictures of the internal views next to the drawn deckplan (in both tail and belly formation) so myself and my players can get the picture.
I also note which squares (floor-panels in traditional deckplan, whilst its both a wall and a floor in mine) that have slots in them to use as ladders.

Captain Jonah, you make a valid point of the ship's set-up being a problem in an emergency, I remedy this by keeping cargo-space on a completely seperate deck (which would be entered via a hatch, either walked through or climbed into :wink: ). This means the ship generally has a bridge (front/top), then staterooms and berths, whatever public space there is, then Engineering at the back/bottom floor.

I know what tail-landers and belly-landers are as I have read Atomic Rockets website and base alot of my planning from the info there. Anyways I have bumped into the cthreepo website and got all my calculations.

I guess all the extra hours of M-Drive fuel helps with ship combat turns (as these are finite with a Reaction Drive).

Thanks for all the help thus far and in the future :wink:

 

[GamerDude]

Sorry if I was not clear. By tail Lander I am referring to ships where the decks are stacked on top of the next, my example being the mercenary cruise. I am not suggesting they actually land. It is an old reference to deck orientation.

Accepted. I wasn't familiar with, as you said, an old reference.