Am I the only one who thinks the BACC booster (the long 1m one) is really rather bad?

[Frostiken]

It seems to me like a large amount of its thrust is wasted just trying to cope with its own weight. It's also rather expensive, doesn't burn for much longer than one would think it should, and honestly it just doesn't feel anything like an upgrade to me.

[MalfunctionM1Ke]

Just for comparison: http://wiki.kerbalspaceprogram.com/wiki/Parts

[Caelib]

Adjust the thrust to match your payload and it's fine. Lowering the thrust will increase its total burn time.

[rodion]

maybe i'm unorthodox in this but whenever i feel that part values are unbalanced i just edit the .cfgs to what i think is fair.

[Empiro]

Yes, this is getting discussed in the other forum:

http://forum.kerbalspaceprogram.com/threads/103569-Boosters-RT-10-beats-BACC-in-every-way

[NecroBones]

Yeah, the Rt-10 is really the best SRB. It has the highest TWR, and fastest burn time, which also makes it the most flexible via thrustlimiting. The BACC is OK when it first unlocks in the tech tree, and you're still using mostly 1.25m parts. Once you get past that, IMHO the SRBs become a lot less useful. The really long NASA/ARM SRB (the S1 SRB-KD25k) feels even more anemic, with a really long burn time, low TWR, and no way to raise it short of hacking the configs.

This is one of the things that prompted me to make SpaceY and have much higher TWRs standard (until the top-end where they're closer to the BACC, but still a lot better than the KD25k)

Left to right:

[table]

[tr][td]#[/td][td]Name[/td][td]Diameter[/td][td]Full Mass[/td][td]Thrust[/td][td]Pad-TWR[/td][td]Burn Time[/td][td]Tech Node[/td][/tr]

[tr][td]A[/td][td]RT-10[/td] [td]1.25m[/td][td]3.7475[/td][td]250[/td][td]66.71[/td][td]30s[/td][td]start[/td][/tr]

[tr][td]B[/td][td]BACC[/td] [td]1.25m[/td][td]7.875[/td][td]315[/td][td]40.00[/td][td]47s[/td][td]generalRocketry[/td][/tr]

[tr][td]C[/td][td]KD25k[/td] [td]1.25m[/td][td]21.75[/td][td]650[/td][td]29.89[/td][td]68s[/td][td]heavyRocketry[/td][/tr]

[tr][td]D[/td][td]S109[/td][td]1.875m[/td][td]29.3125[/td][td]2000[/td][td]68.23[/td][td]30s[/td][td]heavierRocketry[/td][/tr]

[tr][td]E[/td][td]S115[/td][td]1.875m[/td][td]48.9375[/td][td]2500[/td][td]51.09[/td][td]40s[/td][td]veryHeavyRocketry[/td][/tr]

[tr][td]F[/td][td]S211[/td] [td]2.5m[/td][td]58.625[/td][td]2800[/td][td]47.76[/td][td]42s[/td][td]experimentalRocketry (1000)[/td][/tr]

[tr][td]G[/td][td]S217[/td] [td]2.5m[/td][td]97.875[/td][td]3800[/td][td]38.83[/td][td]52s[/td][td]experimentalRocketry (1000)[/td][/tr]

[tr][td]H[/td][td]S223[/td] [td]2.5m[/td][td]137.125[/td][td]5000[/td][td]36.46[/td][td]56s[/td][td]experimentalRocketry (1000)[/td][/tr]

[/table]

[federicoaa]

I use it for contract satellites in kerbin orbits as first stage because is cheap

[Matrix Aran]

I swear up and down by the KD25K. It is without a doubt the cheapest and most efficient first stage engine in Kerbal career mode. I've sent more payload further on KD25K powered first stages than anything else. I particularly like it because of its low thrust to weight ratio and long burn time, those two things make it highly desirable to me as a first stage, especially on any save using FAR or Deadly Re-entry. I rate the R-10 as the worst because it adds next to nothing to the first stage's deltaV when used as a booster for a core stage, and on its own it doesn't burn long enough to ascend at sane G levels, even with aggressive thrust limiting (Particularly seeing as throttling back kills their deltaV).

[Jovus]

It has a different use case from the RT-10. Use the BACC if you want long, low-thrust burn times (because, say, you want an optimal ascent trajectory for your heavier rocket).

[moogoob]

I use 'em. They help, as the previous poster said, make up for a rocket that's just too heavy on the pad and for which the big NASA booster would be overkill. That's what boosters are for, really.

For making an entirely-solid first stage though, the criticisms are probably valid. I don't fool around with those very often. (in fact I name rockets using a solid first stage the "Fool" series after my Tarot-based naming scheme)

[merendel]

I rather like the big nasa boosters. IF you balance the TWR with thrust limiting to follow a decent ascent profile they often burn outright around the time you'd be starting your gravity turn with stock aero. Not as big a deal in FAR but they are still a pretty decent boost and I've been known to make clusters of them to make pure solid first stages. BACC's I rate as poor simply because they are the booster going through rocket puberty. Just an awkward stage where I have no real use for them that isnt done better by other parts. I favor the KD25k's for the long slow burns and the RT's are better suited to those short pushes. RT-10's are just golden for geting off the pad with low TWR. I've had a few launchers that were around twr of 1 on the pad without solids. Normally this would be a waste but strap a few RT-10s on and they come up to 1.5 to 1.7. They get you up to speed and then are promptly dumped when they burn out and by the time they do you've burnt off enough liquid for the main engines to hold you at terminal velocity.

[SickSix]

I will say this:the mission to test the booster above 4 800 meters at 480 m/s is impossible with early parts. I am going to have to cancel it. Not cost effective at this point.

[Jarin]

I've used them for ease of construction, but otherwise, I almost exclusively use SD25ks. 2 or 4 of them (depending on payload) are the primary initial lift for nearly everything I launch.

[Kerbart]

Strap a Kerbal in a command seat on top of it and see how far it goes!

[zarakon]

I've actually used the BACC a lot in career mode quite a bit. It's decent when you're forced to keep part counts low.

[Kerbart]

I will say this:the mission to test the booster above 4 800 meters at 480 m/s is impossible with early parts. I am going to have to cancel it. Not cost effective at this point.

Not cost effective is not the same as impossible. It's quite doable to get the booster to 480 m/s at 4800m. It just won't be one of those days where you go to space.

[Empiro]

Yeah, the Rt-10 is really the best SRB. It has the highest TWR, and fastest burn time, which also makes it the most flexible via thrustlimiting. The BACC is OK when it first unlocks in the tech tree, and you're still using mostly 1.25m parts. Once you get past that, IMHO the SRBs become a lot less useful. The really long NASA/ARM SRB (the S1 SRB-KD25k) feels even more anemic, with a really long burn time, low TWR, and no way to raise it short of hacking the configs.

This is one of the things that prompted me to make SpaceY and have much higher TWRs standard (until the top-end where they're closer to the BACC, but still a lot better than the KD25k)

Actually, I've always found the S1 SRB pretty useful. While I do love the massive SRB in KW (and I think I'll probably give SpaceY a try too), I've found that the S1 is extremely useful for medium sized rockets. Even though the S1 has poorer TWR than the BACC, it only has that because of the extra fuel it carries (the empty TWR is better), and it still has much greater payload lifting capacity (21.5T vs 13.125T at a TWR of 1.5).

Toward the end of my rocket designs, I always ask, "OK so what will I need to get my first stage off the pad and have enough Delta-V to make it into space?" I use Kerbal Engineer, so I know exactly how much dV and TWR I have. For medium sized rockets, I've found that the S1s provide a decent boost to TWR, and often provides more delta-V than expected. The BACCs never do, and seem especially disappointing when I add a bunch and it only adds a few hundred m/s delta-V.

This is especially true in FAR where I often have to limit the thrust on my SRBs, and I rather they provided more delta-V because SRBs are so cheap and economical. I don't consider limiting the thrust on an SRB to ever be a good thing, because it implies that I'd be able to get further if I had the same engine running at full bore, but with more fuel in it.

Edited December 18, 2014 by Empiro

[Torquemadus]

I use solids for all of my first stage needs. In the early game I cluster them as a first stage for conventional rocket stacks, while later on I strap bunches of them to my winged fly-back boosters.

I use thrust limiting to increase the burn time of the solids. This means that they give their best TWR when I'm well into the upper atmosphere and free of any worries about terminal velocity. The solids get me comfortably into sub-orbit and are then dropped. Empty "trash bins full of boom" are worth very little once empty. I then use liquid engines to circularise. The liquid stage is recovered by either by parachute or a runway landing depending on available tech.

I use the RT-10 at the very start of the game, replacing it with the BACC as soon as it becomes available. In turn, the BACC gets replaced by the SRB. I could definitely do with a bigger solid for large payloads in the late game.

[magnemoe]

This is balanced with the cost of radial decoplers who cost 600 or 700, Real cost is not 325 versus 700 or 1800 but rather 925, 1400, 2500 yes you can stack them side by side but its limited how far you want to take that and really is most practical for the longer ones.

[Frostiken]

ITT: people talking about boosters that aren't the BACC.

[foamyesque]

I actually quite like the BACC; I tend to use a pair of them to hoist a lot of my small-to-mid orbital vehicles.

[djnattyd]

Pretty much the only reason to choose the BACC over the RT-10 is that the RT-10 is awful to look at. That and the fact that it looks weird on launch vehicles once they get to a certain length/width.

It's probably better to go with two liquid fueled outer stages over the BACC unless your starting TWR is really low.

[GusTurbo]

I like the BACC for early career mode. It's cheap, and it gets the job done. I actually just used one as the core for an aerial survey contract before unlocking plane parts. Worked great, and I didn't feel bad about dumping it in the ocean.

[foamyesque]

I like the BACC for early career mode. It's cheap, and it gets the job done. I actually just used one as the core for an aerial survey contract before unlocking plane parts. Worked great, and I didn't feel bad about dumping it in the ocean.

My default "get science from space" rocket consists of a parachute, a pod, an RT-10, a decoupler, and the BACC. It costs me a grand total of 1,400 to launch it, 400 of which is the decoupler... wonder if I can do fire-inna-hole-staging and omit it... but anyway, that's less than a single 400 tank feeding a single LV-30.

Hurrah for cheapness!

[Renegrade]

My default "get science from space" rocket consists of a parachute, a pod, an RT-10, a decoupler, and the BACC. It costs me a grand total of 1,400 to launch it, 400 of which is the decoupler... wonder if I can do fire-inna-hole-staging and omit it... but anyway, that's less than a single 400 tank feeding a single LV-30.

Hurrah for cheapness!

I dunno, that's pretty good costwise, but my own BACC-based orbital science craft, cost 6,785, is capable of doing that mission something like 28 times in a single launch with only T4 technology:

That's 242 funds per crew report.. I could slap on more batteries (they're massless anyhow) for more endurance, but it's rare for it to even use half of it's power before I have a solar-powered thermometer probe to replace it with that has unlimited endurance.

(note that it's a FAR design, but without FAR, I could slap on another half-ton of fuel and ditch the fins and actually pay less, stupid fins cost almost as much as a T30 each)