How many large engines?

[Markus Reese]

So I am trying to guestimate how many of an engine I need for a space only ship I am building. A sort of large industrial tow rig. I am still relatively inexperienced in the large building and not sure what is the recommended engines to mass. I have both iron for unloaded, then Hydrogen for fully loaded. What is the sort of relative mass to power ratio one wants for engines as a rule of thumb?

[Blueberry Muffins!]

if you're hauling loads long distances acceleration is almost meaningless, time to peak speed at 1m/s² acceleration is 100s, average speed over that time is 50m/s, so that's 5km at each end accelerating and the rest of the trip is at top speed. So just "industrial tow rig" isn't really enough to narrow the range any. You're towing what, how far?

If you're hand-flying through obstructions you want more maneuverability. If you're fighting gravity you need much, much more go-juice. For an outlier example, I do eight large hydrogen thrusters for my one-large-cargo-container planetary lifter, that kind of overkill TWR could never work in real life but it gets awesome fuel efficiency and would be almost completely wasted in space.

[carl.wear]

You said space only. That reduces the number of engines needed.

Also you don't need ion for unloaded and hydrogen for loaded as hydrogen will do both - BUT keep the ion as a backup for if you do run out of hydrogen.

Good fuel saving tip is, Aim ship in direction of travel, press Z to turn dampeners off; turn engines off and drift.

Also run the hydrogen engines as two groups.
Group one, turns on enough engines to run the ship empty. Group two, turns on the rest of the engines for when you need full power. Running bare minimum of engines helps save fuel / power.

[Markus Reese]

Originally posted by carl.wear:

You said space only. That reduces the number of engines needed.

Also you don't need ion for unloaded and hydrogen for loaded as hydrogen will do both - BUT keep the ion as a backup for if you do run out of hydrogen.

Good fuel saving tip is, Aim ship in direction of travel, press Z to turn dampeners off; turn engines off and drift.

Also run the hydrogen engines as two groups.
Group one, turns on enough engines to run the ship empty. Group two, turns on the rest of the engines for when you need full power. Running bare minimum of engines helps save fuel / power.

The inertial drifting is something I am comfortable with. Going way back to freelancer for that in space travel. I have for flight the main two engines. I am actually working on something a bit different for this. I have a modular engine setup. I can flip and lock the engines to face forward for braking. So primary accel and decel are the same booster without reversing direction. I only had the pair so far. Debated adding a second pair. Though that would also make the ship quite large.

I am mostly unsure what the rate of acceleration/deceleration was like with the big engines. If just having the primary pair would be reasonable for non combat, cargo hauling. The idea is I work with my bro, or tow along a mining vessel. Hauling large volume of ore back to the main station for processing.

[nyannokonekko]

Depends on preference really, I personally like fast agile craft so I mainly use Hydrogen Engines (And a lot of them at that) since I Just build small refueling posts to quickly refill whenever I need.

Also for guestimating the approximate thrust force in G's for whether a vehicle can handle planets or not I do is;
>If it hits 100m/s in 1 second its about 10 G's worth of thrust.
>If it hits 100m/s in 5 seconds its about 2 G's worth of thrust.
>If it hits 100m/s in 10 seconds its about 1 G's worth of thrust.

I like my thrust for forwards to be around 1.5-2 G's
My upwards thrust to be around 2.5 G's
And my left/right/reverse thrust to be around 0.5-1.5 G's

(But a lot of people like less than 0.5 G's for thrusting in space, so it depends on preference)

I hope this lil diagram helps
Feel free to message me any time if you have any questions as well

[TheHellKat]

Typically speaking, cargo haulers tend to be slow to turn and accelerate.

With sufficient gyros and thrusters you can make them fast, but to get to that point you are adding gyros to counter the extra weight of the thrusters and extra thrusters to counter the weight of the gyros.

Basically it becomes wasteful.

I'd suggest taking your build into a creative world and adding thrusters/gyros (when fully loaded) until you get to a number that gives you the handling you are comfortable with.

[carl.wear]

Originally posted by Markus Reese:

Originally posted by carl.wear:

You said space only. That reduces the number of engines needed.

Also you don't need ion for unloaded and hydrogen for loaded as hydrogen will do both - BUT keep the ion as a backup for if you do run out of hydrogen.

Good fuel saving tip is, Aim ship in direction of travel, press Z to turn dampeners off; turn engines off and drift.

Also run the hydrogen engines as two groups.
Group one, turns on enough engines to run the ship empty. Group two, turns on the rest of the engines for when you need full power. Running bare minimum of engines helps save fuel / power.

The inertial drifting is something I am comfortable with. Going way back to freelancer for that in space travel. I have for flight the main two engines. I am actually working on something a bit different for this. I have a modular engine setup. I can flip and lock the engines to face forward for braking. So primary accel and decel are the same booster without reversing direction. I only had the pair so far. Debated adding a second pair. Though that would also make the ship quite large.

I am mostly unsure what the rate of acceleration/deceleration was like with the big engines. If just having the primary pair would be reasonable for non combat, cargo hauling. The idea is I work with my bro, or tow along a mining vessel. Hauling large volume of ore back to the main station for processing.

Modular engine setup. OK, How did you get that to work?
I am curious because the only way I could see to have the same engines be forward and reverse is to move them on a hinge or rotor and that means they are now on a subgrid which creates its own issue of needing scripts to hook the engine controls up to the cockpit.

Also if its a large grid ship, maybe see if a jump drive is viable for long distance travel. ( The catch is, the heavier the ship, the shorter the jump distance so if its too heavy, its not worth it).

[Pembroke]

Thrust output:
Large grid small hydrogen thruster: 1.08 MN thrust
Large grid large hydrogen thruster: 7.20 MN thrust
Large grid small ion thruster: 0.35 MN thrust
Large grid large ion thruster: 4.32 MN thrust

Newton: F = ma
F = force from your thrusters
m = ship mass
a = acceleration

Solving for acceleration: F = ma <=> a = F/m

How big is your ship? Let's say 1,000,000 kg as an example. You can see your ships mass in the bottom right corner when you fly it. Just put in that number instead of the 1 million here.

How much thrust you have for forward movement? Let's say 1 large hydrogen thruster. That's then 7.2 MN i.e. 7,200,000 N.

How much acceleration do we get?

a = F / m = 7,200,000 / 1,000,000 = 7.2 (meters per second squared)

Meaning it will take you 100 / 7.2 = 14 seconds to accelerate from rest to the max 100 m/s speed.

[Daft Helmet]

Originally posted by carl.wear:

Modular engine setup. OK, How did you get that to work?
I am curious because the only way I could see to have the same engines be forward and reverse is to move them on a hinge or rotor and that means they are now on a subgrid which creates its own issue of needing scripts to hook the engine controls up to the cockpit.

If you use a pair of stacked rotors/hinges and line things up right it'll let you merge block the engines back onto the main grid after rotating either way.
There's also the option of just using thrust overrides and accepting crude control as the tradeoff.

[Markus Reese]

Originally posted by carl.wear:

Modular engine setup. OK, How did you get that to work?
I am curious because the only way I could see to have the same engines be forward and reverse is to move them on a hinge or rotor and that means they are now on a subgrid which creates its own issue of needing scripts to hook the engine controls up to the cockpit.

Also if its a large grid ship, maybe see if a jump drive is viable for long distance travel. ( The catch is, the heavier the ship, the shorter the jump distance so if its too heavy, its not worth it).

Currently the server is off. I will try to get you pictures the next time it is on line. I actually do it without stacked rotors/hinges and in a way that it can re-lock so the ship can stay all one grid. My intial test was actually rotating gun ports.

Keep in mind, I design it for more fun and flavor RP. Not pvp or optimal efficiency. But it looks really cool. My initial testing was on creative where I did a gun port that flips between twin railguns and artillery. Press a button and the railguns fold away. Artillery pop out.

Currently I only have the first engine layout, but it is plenty to show how it is working. I did discover one slight error with how I lined things up, but minor as it still works overall. Also I do some more stuff as fluff which makes it larger than it needs to be. But hey, it looks cool. Especially when watching it from the main corridor windows.

For Pembroke, thanks for the numbers. Two engines would mean 2m kg at 7 seconds. I am fine with slower acceleration. So if I scale based off my current ship when loaded, It would still be kind of slow, but not unusable when under full load with hydrogen and the ions should be more than adequate for slowboating around.

As for build into creative, well that is where it my own self torture starts. Building it from theory.

It shouldn't be too heavy. The concept of the design is not to be a self contained unit. More like a semi truck. Relying on my base which already has docking ports for quicker loading and unloading. So no mining drills or refineries or assemblers, etc on it. Will be larger in size, but also more void on the inside.

[Dan2D3D]

Hi, the main "Rule" about thrusters is always the same so doing the "Math" is not needed.

Main Thruster Rule :
-> a minimum of 2 large Upward thrusters are needed to support one Full load Large Cargo container on Planet and will need a bit more to have a better maneuverability and avoid crash landing.
+
-> We know how much thrusters will be needed on all the other sides once we know how much Upwards are needed to hover and stop fast when Full Load.

_______

That said, example of "Nuclear Ion space ship", you need :

1 - Cockpit.
2 - Gyroscope.
3 - Nuclear Reactor.
4 - ION Thrusters on all sides.

5 - Enter the cockpit, try the ship and add more of #2, #3 and #4 if needed to have a better maneuverability = it goes with the total mass of the ship so you will need more on bigger ships.

6 - Full all its containers + connectors + O2/H2 Gens to see if it can fly full load and add more of #2, #3 and #4 if needed to have a better maneuverability.

[Dan2D3D]

I will add :

The best ships are the one able to stop 100m/s to 0m/s in 4 seconds when Full Load.
+
Also able to fly on all sides on Planets but that needs a lot of thrusters and power.

[Captain Canard]

On my large and heavy mobile refinery, I put more emphasis on braking thrusters than main forward thruster. I don't care if it takes me a minute to go from 0 to 100, especially since a jump drive will get you close to any space-based destination. Oh, that ship as NO large thrusters, as multiple smaller thrusters worked better for that design.

On the other hand, I had a small (large grid) personal ship that had two large H2 thrusters that could go from 0 to 100 in like a second, and that was a ton of fun and a great way to put distance between me and slower enemies while the jump drive charged up. It had weak brakes, but I would just do a flip and burn to slow down, like in The Expanse.

[Markus Reese]

Originally posted by REALRACE:

yes, those forward thrusters ... i learned quite fast, NOT to aim for an asteroid :p

(btw. i really do not understand, what is funny about visiting a casino with an infinite amount of money ... well, besides the god-feeling perhaps ... this would take so much away - at least from my playstyle)

So true! Is almost habit for me as well. I do use creative for testing theories and such. But for building working products in game, is part of the experience of doing it through resource collection and processing. Using my welding ship to construct and fill sections and so on.

[Scorp0102]

note that is more space efective to use small thrusters instead of large ones as for hydrogen large thruster 3x3 base u get 7.2 MN and small one does 1.1 MN so in space 3x3 u can get 9.9MN with small thrusters

[Markus Reese]

Hrm... I will need to remember that for next time. Maybe my next ship I can use a folding array.