SRBs underpowered.

[Comrade Jenkens]

While messing around with a stock space shuttle I've found that even the new huge SRBs don't even come close to being able to acts as the main boosters. Their power is about right but their burn time is still too short to be useful. This is also a big problem for Ares 1 replicas.

This is shown very clearly with the SLS parts. In the real version the boosters provide most of the thrust while the core stage only has a TWR of 0.75. With the KSP versions the core stage is so powerful and the boosters are so weak that they aren't even needed.

Who else thinks that they need a buff?

[karolus10]

Interesting fact is that SRB's with same fuel and diameter but different length will had equal burn time (thrust limiter would be very useful for longer ones sometimes) and thrust increasing with length.

[Javster]

I struggle to think how the MOAR BOOSTERS thing got started with only 2.5 real SRB's in the game (sepatron is 0.5)

[manuelasa1999]

I really think that we need larger and more powerfull SRBs of different sizes...

[coolitic]

SRB's may have less power, but their thrust-weight ratio is very high compared to liquid fuel engines + liquid fuel tanks.

[Temeter]

Afaik SRB arent supposed to be more effective than liquid fuel rockets(/booster). Their main advantage in real life is being cheaper and reusable.

Edited April 3, 2014 by Temeter

[SpacedCowboy]

I struggle to think how the MOAR BOOSTERS thing got started with only 2.5 real SRB's in the game (sepatron is 0.5)

Yeah, really! You got that right. You know the old saying; "Why look a gift booster in the nozzle ?"

[LostElement]

I am inclined to agree. I've recently been trying to use SRB's as main boosters. Maybe they should have SRB nozzles. and Solid fuel tanks. Just like with Liquid engines.

[Kerbart]

It would make things a lot easier if you could get anything into orbit by just slapping on a few SRB's and you're good to go. I have no problems with the current setup. I view SRB's as "when you're just a smidgen short of delta-V to get into LKO and a dozen or two of boosters can fix that"

Not to mention the entertainment factor of ejecting your boosters before they're completely burnt out. Always good for a rapid (not not totally unplanned) disassembly.

[kujuman]

I wouldn't say that we have "under-powered" SRBs in the game, but rather that we don't have stock SRBs large enough for the kind of heavy lifts people are doing these days.

No, it's not a contradiction. Most real world uses of SRBs are as small supplemental rockets to enable a slightly heavier payload or to eek out a bit more performance. For these uses, the stock SRBs are great. And who hasn't stuck LFTs on top of SRBs with crossfeed to the core to get a simple way to increase performance?

It's the Space Shuttle SRBs that I think people really think are "proper" SRBs. For these types of launchers, we do need larger SRBs. To put things into perspective, an Orbiter weighs about the same (with a medium payload) as an empty shuttle SRB.

In sum, for a simple LKO crew vehicle, existing SRBs can be a significant fraction of the lift vehicle, but are limited to being supplemental boosters on heavy-lift vehicles.

[Jouni]

No, it's not a contradiction. Most real world uses of SRBs are as small supplemental rockets to enable a slightly heavier payload or to eek out a bit more performance. For these uses, the stock SRBs are great. And who hasn't stuck LFTs on top of SRBs with crossfeed to the core to get a simple way to increase performance?

There are two kinds of SRBs in use. One is those supplementary rockets with typical burn times from 40 to 90 seconds, and the other is big SRBs that are really the first stage of the rocket, with burn times ranging from 120 to 150 seconds. In addition to the Space Shuttle, Ariane V, Titan IV, and the Japanese H-IIA and H-IIB also use those big boosters.

[Sirrobert]

I struggle to think how the MOAR BOOSTERS thing got started with only 2.5 real SRB's in the game (sepatron is 0.5)

Liquid boosters are still boosters

[Random Tank]

I'm liking the general direction of this thread; we don't need the current SRBs buffed, we just need new, stonger ones (that could be later in the tech tree). Something like the KW rocketry Thor but with double the burn time

I like the new SRBs added by the ARM patch, they're really fun and I like the FX; we've needed something bigger than the BACC for a while; but proper SShuttle or SLS type launch stage boosters are kinda needed; if only for some variation to launch stage templates!

[John FX]

I like the current system for reasons of gameplay. I use SRBs the same as another poster here. I`ll build a craft and if I am slightly short of Dv I`ll use a few SRBs, sometimes I lift the entire craft to about 5-10km and 150-200m/s and then activate stage 1 to get a better ISP from the larger engines.

Sort of like having a launchpad at 8km moving at half the speed of sound vertically.

Really helps.