What are good engines for Eve's atmosphere?

[OneMuskyOx]

I designed an Eve lander that had ridiculous amounts of thrust and deltaV, being able to escape the solar system flying straight from the launch pad. I took the big guy to Eve, successfully landed it after 2 enraging hours of overheating and quicksaves. I did all my science stuff, got back in, and powered up the engines full throttle. It just popped off the legs, keeled over, and blew up in a way that honestly made me laugh.

I tried to stick with engines that (on paper) had good atmospheric ISP, though I guess they aren't much good. What engines can put up with Eve's atmospheric pressure? I'm not keen on solid boosters because I always mess up the controls.

[OneMuskyOx]

So in essence the ISP gets so bad the rocket can't even lift its own mass it seems. I'll try to drop on a higher altitude this time.

[Celtic Frost]

Intuitively, I would think that bouyancy would be taken advantage of in such a thick atmosphere utilizing balloons. But that doesn't exist in the game yet so... there are mods that utilize bouyancy for airships but they are a bit of a cheat since there is no energy cost implemented to inflate or deflate the balloons.

Short of this, I would expect a jet turbine to be a solution but I can't recall if squad parts has anything that uses atmospheric thrust without ambient oxygen for air intakes.

[OneMuskyOx]

Gravity turning on Eve sounds rather difficult. I'm under the impression that blasting straight up with a ton of early stage rockets is necessary, though even this is inefficient. Having a large base of rockets also makes the ship fatter, and therefore more drag.

I really, really, REALLY wish bouyancy was more significant in this game. Being able to dirigible your way to the upper atmosphere before using the engines would be very helpful. I think if we were ever inclined to land on pressure cooker planets or float on gas giants, balloons are the only choice, assuming we could make a balloon membrane tough enough to even handle the pressure. If we were wizards and could make an extremely durable and light material, we could just make rigid, hollow spheres that are equalized with the atmosphere when descending, then are slowly emptied until the pressure difference is sufficient to begin floating, achieving near vacuum within the spheres. The displacement would be incredible. Hell, if the material was light enough we could use it on Earth.

Now that I think of it, weren't "Vacuum Dirigibles" a proof of concept somebody whipped up a long time ago?

[DaS]

Αναρτήθηκε αρχικά από Blue Space Communist:

Gravity turning on Eve sounds rather difficult. I'm under the impression that blasting straight up with a ton of early stage rockets is necessary, though even this is inefficient. Having a large base of rockets also makes the ship fatter, and therefore more drag.

I really, really, REALLY wish bouyancy was more significant in this game. Being able to dirigible your way to the upper atmosphere before using the engines would be very helpful. I think if we were ever inclined to land on pressure cooker planets or float on gas giants, balloons are the only choice, assuming we could make a balloon membrane tough enough to even handle the pressure. If we were wizards and could make an extremely durable and light material, we could just make rigid, hollow spheres that are equalized with the atmosphere when descending, then are slowly emptied until the pressure difference is sufficient to begin floating, achieving near vacuum within the spheres. The displacement would be incredible. Hell, if the material was light enough we could use it on Earth.

Now that I think of it, weren't "Vacuum Dirigibles" a proof of concept somebody whipped up a long time ago?

In lower EVE atmo your not exactly going warp speed therefore drag is the LEAST of your concerns. In most builds by the time you built up enough speed for drag to even matter you've likely already dropped most of the luanch mass(and surface area). Eve is pancake friendly. There is no rational reason to have a luanch vehicle with more than 1.03-1.5ish TWR anyway unless you just like waisting fuel.
EDIT:
Nor do you require stupidly huge vheicles(although those are more fun)
http://steamcommunity.com/sharedfiles/filedetails/?id=263121233
http://steamcommunity.com/sharedfiles/filedetails/?id=263145182
http://steamcommunity.com/sharedfiles/filedetails/?id=263145208
http://steamcommunity.com/sharedfiles/filedetails/?id=263145228
http://steamcommunity.com/sharedfiles/filedetails/?id=263145273
http://steamcommunity.com/sharedfiles/filedetails/?id=263145292
http://steamcommunity.com/sharedfiles/filedetails/?id=263145343

[George Kerman]

Hey homie,

These are good engines for Eve:
Mammoth
Vector
Aerospike
Skipper (surprisingly OK, same mass as 3 aerospikes, better TWR but lower ISP).
Mainsail and TwinBoar

For example, this ship:
http://steamcommunity.com/sharedfiles/filedetails/?id=862563447

I've tested it last weekend to land and take off from Eve ASL for a longer series that I wanna do. I didn't take pictures of that or videos, that will follow, it was just a test drive.

But the basic staging and process is as follows:
1) the 4 side towers are decoupled before launch from Eve, they were used for interplanetary travels for a higher dV
2) GO!!
3) You can almost go full throttle because of the aerodynamic friendly shape and relatively low-ish TWR.
4) Eject the first stage of 4 Mammoths
5) Eject the second stage of 4 Mammoths
6) Eject the last stage of just one Mammoth
7) Circularize with the Skipper
8) Go home; if the ascent is done even slightly better and with more tries than me, you don't even need the last Terrier stage.

For even better performance, you can even start with the 4 towers attached. They will eventually lift after using some fuel. Careful at decoupling though.

After seeing how smooth the take off from Eve went, I must admit that I've overdone the rocket, but I had many considerations in mind, like costing precisely 999,999$, having ~5.2 - 5.3K dv for interplanetary travels and so on.

But I really disagree that you can take off with whatever shapes from Eve, especially ASL. It's not just a theory, it's what I tried before. For example this rocket:

http://steamcommunity.com/sharedfiles/filedetails/?id=860329918

This rocket was killed by drag on take off.

The drag will destroy your early performance and you might even tilt at only 100m/s! It's advisable to have aero friendly shapes for every planet with atmosphere if you can.

[George Kerman]

Αναρτήθηκε αρχικά από RoofCatA:

yep, Eve drag is terrible......


And solo Vectors are so expensive :(

I couldn't agree more with all you've said. Just that this rocket that I tested could go faster than 100m/s early, I forgot the exact numbers at key points. I'll see them again, hopefully next weekend or so. But mine was piloted straight up until higher up, i think 30km or so. It'd flip if angled earlier and all my RW got dropped at the ground level, so steering was only from gimbal.

[DaS]

Αναρτήθηκε αρχικά από RoofCatA:

You just kissed a girl on the shoulder and want us to call you man? Get down!


1.5 year old example (easier drag) starting from a 7km high mountain. Really? Are you fncking serious this is a relevant launch example? Go beach level now in v1.2+ or go home.

Despite popular belief you can reach relatively high speeds in lower Eve atmosphere if your ship is built accordingly. It saves a lot of vertical G time. And because G is m/s² or m/s per second, you want to have that as short as possible. Also as short low kN and low Isp trap as possible as well. Below 5km 120..150m/s easily, above that 300..600+m/s. Above 55km you are basically unlimited.

Ignorant, fat ships with empty tanks at landing may have probably 50m/s falling speed. So you may believe terminal velocity for all of them is that. And then you may also believe terminal velocity is the speed at which ships should launch (which is bs as we know). Anyway, I have seen failed launch ships (slim, optimized atomic tests) going down with 650m/s below 5km altitude there. So the range of optimal speeds in low Eve atmosphere is actually quite wide and depends heavily on ship design.

Angry much? try this then
http://steamcommunity.com/sharedfiles/filedetails/?id=379296440
http://steamcommunity.com/sharedfiles/filedetails/?id=379458274
http://steamcommunity.com/sharedfiles/filedetails/?id=379479931
http://steamcommunity.com/sharedfiles/filedetails/?id=379479952
http://steamcommunity.com/sharedfiles/filedetails/?id=379479994

http://steamcommunity.com/sharedfiles/filedetails/?id=379499106
http://steamcommunity.com/sharedfiles/filedetails/?id=379499157
http://steamcommunity.com/sharedfiles/filedetails/?id=379499175
http://steamcommunity.com/sharedfiles/filedetails/?id=379499225
http://steamcommunity.com/sharedfiles/filedetails/?id=379499275

[George Kerman]

Are those engines friggin Rhinos or I am not seeing the nozzles right?

[DaS]

Αναρτήθηκε αρχικά από George van Doorn:

Are those engines friggin Rhinos or I am not seeing the nozzles right?

yea they are to provide dead lift, with spikes for the core for acceleration

[George Kerman]

Αναρτήθηκε αρχικά από DaSkippa:

Αναρτήθηκε αρχικά από George van Doorn:

Are those engines friggin Rhinos or I am not seeing the nozzles right?

yea they are with spikes for the core

Really Rhinos? That have Isp of 205 ASL/ 340 VAC?

[DaS]

Αναρτήθηκε αρχικά από George van Doorn:

Αναρτήθηκε αρχικά από DaSkippa:

yea they are with spikes for the core

Really Rhinos? That have Isp of 205 ASL/ 340 VAC?

/shrugs they get the job done and keep parts counts low. who am I too complain

[George Kerman]

In the meantime I found the discrepancy on the wiki:

Changes
1.2
Specific impulse at sea level decreased from 255 to 205.

Before 1.2 it might've been decent ASL.

[DaS]

Αναρτήθηκε αρχικά από George van Doorn:

In the meantime I found the discrepancy on the wiki:

Changes
1.2
Specific impulse at sea level decreased from 255 to 205.

Before 1.2 it might've been decent ASL.

Looking back I tended to use em alot, easy to work with
http://steamcommunity.com/sharedfiles/filedetails/?id=626621578
http://steamcommunity.com/sharedfiles/filedetails/?id=397997594
http://steamcommunity.com/sharedfiles/filedetails/?id=252104705
(side note: they no loger work well on jool < 10k)

[DaS]

Αναρτήθηκε αρχικά από RoofCatA:

Αναρτήθηκε αρχικά από George van Doorn:

Really Rhinos? That have Isp of 205 ASL/ 340 VAC?

his screenshots are again quite old - from Jan2015, when Rhinos still had 250-340Isp, drag was different and some small parts probably still weightless. Non relevant.

While true I always slow luanched which made drag pretty much irrelevant anyway, and unless I'm mistaken none of the NASA parts(which are the primary ones in those "old" screenshots) were "weigtless" been awhile since I played so I may be wrong

[Delle(DK)]

regarding eve.. Try landing on top of a mountain then you need less Dv to go back into space..

"The highest peak on Eve in is 7540 m
So if you can land on top of that mountain you save allot of flying, and allot of fuel.

Takeoff dV required from this height - 7968m/s ( OLD version of ksp many version ago )