Is it better to use bigger engines on a CV, or a lot of smaller ones? has anyone done any tests on this? I'm building a decent sized CV, say 60-70 blocks and I was thinking about using the XL engines. Do they burn more fuel then a few of the smaller ones? I figured on using 10 - 20 RCS's to get it nimble.
The best way to figure that out IMO would be to just figure out how fast you want it to go, and use XL for major amounts of speed, L for finer tuning, and the Normals for that precise numbers. Although the amount of blocks I use normally are in the thousands. Sometimes in the hundreds if i make a more conservative build. 60-70 blocks kinda seems a very small amount.
There are lots of ways to compare them too. Note that I am using stats off the wiki to show these calcs and can't check in game at the moment to verify the stats of the thrusters. Size - An XL thruster takes 3x3x6 blocks, or 54 in total and provides 800MN of force. in that same space, you can fit 27 normal thrusters providing 540MN of thrust, so on this basis the XL is best. Power consumption: Our XL thruster uses 30MW to provide 800MN of thrust, the normal thruster (at 1MW in for 20MN of thrust) would need 40MW of power (40 thrusters) to provide the same thrust. We can also look at the efficiency, being the XL provides 26.7MN thrust per MW in, normal thruster 20MN per MW in. So the XL is more efficient here. There are also power to thrust ratios that can be calculated too, but it gives similar stats, i.e. the XL is better. You then however need to look at your ship. A CV's max speed in space is 92m/s. I like to aim for acceleration of 30m/s as a minimum so you can get to max speed in about 3 seconds. If your ship is 60-70 blocks (total? long? etc) then, while the XL is more efficient, you may not need all that power, so to achieve your acceleration of 30m/s you may only need 5-6 Normal Thrusters, and while not as efficient, you are not using the same total power as if you put in a XL thruster. Some other considerations: 1. If you PvP, then as weapons can now target engines, it pays to sacrifice the efficiency of the XL one and have lots of Normal Thrusters to provide you redundancy and make it harder to have your ship disabled. 2. I have heard a rumour that thrusters are going to need to be exposed to the outisde to work once they bring in pressurized interiors (6.0 release). Dont know if this is true, but if so, having lots of normal thrusters may make it hard to place on the outside of your ship so you may need to go to a combination of sizes. One last thing to check with your acceleration is that your lift is at least 20m/s. That way you can go straight up off any standard planets gravity. 10-20 RCS is good for that size. Hope this helps
Thanks for the help guys. Sorry I didn't mention that was 60-70 blocks long. Given I have 4 decks, I haven't calculated the total tonage yet. I'm building a carrier of sorts so we can bring all my smaller ships and HV's with us. the HV hanger is 20 blocks. I wanted to keep it kinda small, but I may go for 40. Come to think of it. the total ship length could exceed 200 blocks. I'm using 4 XL's on each side with 4 downs, and 4 up's. (up's ???) My engines sit off and high from the ship so it has a smaller ground footprint. Cockpit's not designed yet so I don't know if I'm going wide or thin with the bow of the ship.
Once you have the total tonnage and decide the acceleration you want for each direction, we can do some calculations. 4 XL's seems like a lot though, so unless you're placing some for aesthetic reasons, you may be using a lot more power than you need. If you want them there to make the ship look good, you can put the thrusters you don't actually need to be running into a different 'p' menu group and leave them switched off. Then use lights of varying colours to provide some good lighting effects for them, that way, power usage drops.
Additionally, if you are using 4 XL thrusters for forward flight, that is 120MW of power, a Fusion cell provides 300 so you are using .4 Fusion cells / second just to run engines. To get an hour space flight you need 1440 Fusion cells = 22.5 T3 Fuel Tanks... that is a lot of manufacturing to be done and that is only thrusting on one axis
I build largely for aesthetics, but I keep in mind that ideally, the larger the thruster, the more efficient it should be. I know it isn't balanced that way at the moment; I don't give a crap. Ive seen a few refits of my own ships with nothing but stacked medium thrusters (for PVP) and I respect that people will want to "ruin" my workshop vessels to satisfy their own needs, that's why they're public and that's why I invite feedback/ comments/ suggestions/ criticism. Go check 'em out!
Keep in mind that if you are going to be using a small number of blocks, the XL thrusters will likely off-balance your vessel. You may find that when you land on a planet, it will flip itself so keep an eye on the center of mass as you're building. One more point; even though XL thrusters will provide much more thrust, smaller thrusters will give you the same relative performance because of the small size of your CV.
I also build for aesthetics and if every last thruster has to have the nozzle exposed I think I would likely find something else to do with my free time. My Lil Piggy line of SVs and HVs would be pretty unappealing. My Bullfrog compact CV would look horrible. I actually can't think of any of my own designs or others that I find aesthetically pleasing that wouldn't be completely ruined if this were done.
1 factor to take into account is mass. More mass needs more MN. Usually 100k+ Ships need XL thrusters as they were designed for them. Under 100k tons u good to go with L thrusters. S are for light Cvs- as they are very handy. Its useless to put S or L on a 200k ship aa it'll do almost nothing. Ofcourse there is the MINimum speed but who likes to travel at 1m/s? Keep in mind Thrusters themselves add weight. For big ships its nothing(well it is something but it dsnt matter they already heavy). If you add XL thruster to 100k< ship you will gain lots of weight. And like it was said- they burn fuel like no tomorrow. When you are looking at XLs keep in mind starting 20T3 fuel cells and up. Currently in empyrion in PVP mode XL and 200k ships are for clans who can manufacture the fuel needed to run them. If you are on single player- and if you want to do it without console commands- L thrusters are way to go here. Its the Newtons that thrust the ship! How much Newtons you need is how heavy your ship is. And that we get from hitting P key and statistics. NB! Also its not wise to add more thrusters than actually you need as they have idle burn too- even if you turn them off. In PVP every fuel cell you waste equals the time you had to have it.
To work out the Force you need in MN, multiply the weight of your ship (in kT, as a kT=Mkg) by the acceleration you want to achieve (in m/s2). You can then look at which Thrusters provide what force at what power requirements and choose quantites of thrusters based on that. you can then decide to mix and match based on aesthetics, fuel consumption and overall qty of thruster you want (last one based on PvP mechanics). Note, if you have 4 XL for forward thrust that is 3200MN of force. If your ship weighs 10kT, then your acceleration will be 320m/s2 which is very quick and power hungry
I cant upload an excel workbook, but here is a screenshot including some generic examples. Notes: 1. Does not account for using a mixture of types of thrusters. 2. Up to the user to decide which thrusters to use based on aesthetics. 3. Up to user to choose qty of thrusters based on providing redunduncy and extra targets if PvP'ing.
The directional thrusters are the most fuel efficient but you have to have more of them. The XL thrusters give you the fast acceleration so the best response time but suck huge amounts of fuel. So what I do on a lot of big ships is build two engine systems one of directional thrusters and just have enough to hover in atom good and move a little, and another system of XL thrusters that I call afterburners which I leave off most of the time and only turn on if I need more acceleration for combat or need more power to hover on a higher gravity planet. But I say don't worry about all those calculations really they don't help much. The main thing that you have to keep in mind is 1 gravity is 9.8m/s so if your ship can do that or above you are good to hover in a 1 gravity planet.
Bigger engines just provide faster acceleration and consume a large amount of fuel. I have a fairly large CV with 12 large thruster. 6 forward and 6 backward. I found that I could reach top speed in about two seconds. Not really necessary, but if you were in PvP you may want the extra boost. I suggest trying two thrusters or whatever low number looks correct on your ship. One on each side or one in the middle. Whatever style you are going for. If the ship is super sluggish then add more. Due to gravity I have additional thrusters on my ship. The extra large thrusters that add acceleration aren't always needed and the downward thrusters I have for high gravity planets aren't always needed either so I keep those in a second group and powered off until I need them to save fuel.
Wow, my brain hurts. lol I have a screenshot of the completed ship. I wound up with 30 large engines and I think I have too many. I have 31 RCS's to make the ship nimble but I'm not too sure I need them. I'm sure after posting this and talking with you guys I may want to rethink the engines.
Your ship is 73.6 kT, and with that configuration of engines, should give you acceleration of: U = 16.3 m/s2 L = 8.15 m/s2 B = 21.7 m/s2 R = 8.15 m/s2 D = 16.3 m/s2 F = 21.7m/s2 On standard game, Aitis i think is the heaviest gravity at 1.22g, so with 16.3m/s2 U, you will be able to get off of it ok. The rest of the accelerations are fine, you'll get to top speed forward in 4.5 seconds or so. I prefer to get slighlty more acceleration in the forward direction, but that is only a personnel preference.
I think its depends on what you want. Try it out, see if you want/need it. I like building ships with a purpose - and match the performance to that purpose. Not every ship needs to be fast & agile.
I'd only really worry about adding more if you PvP in multiplayer. It would give you faster escape, spare engines if you lose some and extra engines to distract enemy fire. If you are a SP or multi PvE only, there is no real need for more than you have
As magnusshields said, I may want to keep some engines turned off. Here's the final design. She was designed as a PvE floating base that is able to land on different planets. I designed the engines to sit high above the trees. (No resemblance to Star-trek was intended.) I'm posting photos and the specs so you can see how big this is. It's my biggest ship yet, but it came with a price. I have T2 fuel tanks and I can watch one go dark about every 5 minutes. I think I may be way overpowered. Photos Specs: I took these 2 seconds apart! See how the fuel went down? I can't afford to run this. Loadout, engines and stuff I truly appreciate any and all help from my fellow builders. I'm not new to the game but new to building capital ships, and I can always learn more. I should also mention that we haven't finished the final look yet, or the placement of guns. I wanted to get it into the game and see how it handled first.
