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KSP Loading... Preview: New SRBs

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55 minutes ago, coyotesfrontier said:

I think half-scale is more logical then the 66% that a lot of others use, so I'd go with 1.875m. Squad seems to be going with 66% scale/2.5m to fit with the twin-boar, but that makes the boosters almost as big as the 3.75 SLS parts they're intended to be attached to.

At this point I will see how it function, and if it works, stick with it.

Already ran a test flight using 2x2 Kickbacks on Shuttle and it's stable enough with orange tank to a LKO.

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For me, external tank has to be 5m, so the 2.5m SRBs are just right.  Now, I just need orange variants of the 5m parts. 

2.5m External tank is way too small.

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3 hours ago, klesh said:

For me, external tank has to be 5m, so the 2.5m SRBs are just right.  Now, I just need orange variants of the 5m parts. 

2.5m External tank is way too small.

I know. but what about Ares I?

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22 hours ago, klesh said:

For me, external tank has to be 5m, so the 2.5m SRBs are just right.  Now, I just need orange variants of the 5m parts. 

2.5m External tank is way too small.

Ha, you should see the Gemini adaptor section. Gemini replicas (at least for me) are a disaster since I have to make the Titan stage a 2.5m part rather than use the nice and sleek new 1.875m engines and fuel tanks since they're the same size as the Gemini and the Titan is wider in diameter than the Gemini requiring that conic adaptor section to be included in replicas. 

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On 9/18/2019 at 11:43 PM, Jestersage said:

I know. but what about Ares I?

Indeed, that does present a dilemma.  If you use the 2.5m srb for that, then your crew pod is going to be way too small at 2.5m.  We need that Mk3 Command Pod in Orion style.

On 9/19/2019 at 6:25 PM, ZooNamedGames said:

Ha, you should see the Gemini adaptor section. Gemini replicas (at least for me) are a disaster since I have to make the Titan stage a 2.5m part rather than use the nice and sleek new 1.875m engines and fuel tanks since they're the same size as the Gemini and the Titan is wider in diameter than the Gemini requiring that conic adaptor section to be included in replicas. 

 

I'm certainly aware of that.  In fact, I made a thread about it 2 days after Making History came out, but unfortunately only one other KSP forums poster found it discussion worthy. 

Short story shorter, the Mk2 Command Pod is too big.

 

 

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2 hours ago, klesh said:

Indeed, that does present a dilemma.  If you use the 2.5m srb for that, then your crew pod is going to be way too small at 2.5m.  We need that Mk3 Command Pod in Orion style.

 

I'm certainly aware of that.  In fact, I made a thread about it 2 days after Making History came out, but unfortunately only one other KSP forums poster found it discussion worthy. 

Short story shorter, the Mk2 Command Pod is too big.

 

 

I think the pod is fine- the problem is the Gemini rocket parts needs to be 2.5m. Instead the 1.875m parts should be like Jupiter or Thor rocket sizes. 

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Its one or the other. If you think the Command Pod Mk2 is fine and the Titan II should be 2.5m, then all the Apollo parts are out of scale.  Bottom line is indeed, the scale in the game is right in some places, off in another.  Some things work together, but when juxtaposed to something else, its out of whack.  I hope KSP2 is a little more consistent in this regard.  I fear it will just have all the old KSP1 parts in there, in the same mismatched scale + a bunch of new interstellar parts, continuing the problem.

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3 hours ago, klesh said:

Its one or the other. If you think the Command Pod Mk2 is fine and the Titan II should be 2.5m, then all the Apollo parts are out of scale.  Bottom line is indeed, the scale in the game is right in some places, off in another.  Some things work together, but when juxtaposed to something else, its out of whack.  I hope KSP2 is a little more consistent in this regard.  I fear it will just have all the old KSP1 parts in there, in the same mismatched scale + a bunch of new interstellar parts, continuing the problem.

I think they just need to make the 2.5m part variants for Titan and Saturn IVB sizes.

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On 9/18/2019 at 11:31 AM, KerikBalm said:

I hope thats 1700kn for the short 2.5m, and 3300kn for the long 2.5m diameter one, not a 1700 kn sea level thrust, and 3300 kn Vacuum for the long 2.5m diamter ones (the big ones or the big one type) .

That seems to be about 5x a kickback. 

The real shuttle has 82% of its sea level thrust come from the boosters. So the SRBs for a proper mockup would have 5.76x the seal level thrust of 3 vectors. Now since sea level thrust hasn't been specified, and in game vectors are pretty good at sea level like SRBs, I'll just compare vacuum thrusts.

3x vectors: 3,000 kN ... what 2x SRBs should produce for a similar proportion: Just over 17,000 kN. What we get: 6,600 kN.

A 2x large SRB + 3x vector combo has about 69% of its thrust come from SRBs... not bad, but still low. It will be interesting to see if these allow for shuttle style launches in a 3x rescale, because everything else performs reasonable well at 3x (rapiers can SSTO for instance, I can make reasonable saturnV replicas, although I need more mastadon and skiff engines than the counterpart), but shuttle style designs have eluded me so far due to the relatively poor SRB performance. I'm eager to try these new ones.

Good analysis here.  I have an alternate take though - the Vectors (despite obviously being modeled on the RS-25) aren't the best choice for STS-style shuttles in stock KSP.  Too much power (shuttle/ET TWR was far lower what we get with 3 Vectors in a STS lookalike), FAR too heavy (very difficult to make STS-lookalike CoM/CoL work with 12 tons of dead weight hanging off the tail, unless you add huge ballasts to the nose).  Try 3X Skiffs, and you'll find yourself encountering design challenges that feel a lot more realistic.  On the downside, they could probably use the large gimbal range from the Vector.

You'll still have far too much delta-V in the end with a proportionally-sized external tank, but like all KSP things that too goes away your ~3x stock resize

Edited by fourfa
double post

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Ughhh skiffs... Their thhrust is too low IMO, they should be closer to skippers in terms of thrust.

Plus they just got a massive nerf.

Taking a 3.75m long tank at 81 tons, lets say 60 tons by SRB burnout, a 25 ton payload, and another 15 tons of mk3 cockpit, wings, fins, cargobay, landing gear, thats 100 tons. You want at least a 2:1 TWR (the shuttle had that), you're looking for at least 2000 kn of thrust.

And in 3x, that fuel fraction won't cut it.

I know 3x isn't stock, but it's my standard, since everything else seems challenging but balanced at that scale... Except shuttle replicas (and saturn V replicas if you don't cluster more than 5 engines, particularly the skiffs)

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9 minutes ago, KerikBalm said:

Ughhh skiffs... Their thhrust is too low IMO, they should be closer to skippers in terms of thrus

Them use the BetterSRBs mod to get more realistic numbers, or a mod I'm working on (Modular Segmented SRBs) for the same thing

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On 9/4/2019 at 6:09 PM, StrandedonEarth said:

Or a 3.75m docking port?

Or a 5 m docking port?

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Posted (edited)

So I'm living in a cave and just heard about this and I'm super stoked about it!  But I do have one question about the thrust. 

On 9/4/2019 at 5:02 PM, Maxsimal said:

1700kn and 3300kn in vacuum.   They'll rattle some windows.

Taking these numbers at face value would mean the Isp doubles from 1atm to vacuum.  [edit: or Rocket Witch could be right in the post below.]  This would be unusual to say the least for an engine intended for the launchpad.  I suspect that one of these is wrong; dare I hope that 1700 should be 2700, or is it that 3300 is 2300? 

On 9/10/2019 at 2:38 PM, Rocket Witch said:

So people have asked about thrust and gimbal, but what about Isp? Will stock vacuum SRBs ever be a thing? They're rare enough in mods as it is...

On the other hand, a vacuum-optimized SRB would make some people happy...

Edited by FinalFan
see edit

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4 hours ago, FinalFan said:

Taking these numbers at face value would mean the Isp doubles from 1atm to vacuum.  This would be unusual to say the least for an engine intended for the launchpad.  I suspect that one of these is wrong; dare I hope that 1700 should be 2700, or is it that 3300 is 2300?

I think they meant the short 2.5m SRB has 1700, and the long one has 3300.

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On 10/6/2019 at 11:10 PM, Rocket Witch said:

I think they meant the short 2.5m SRB has 1700, and the long one has 3300.

That's correct.  ISPs are slightly higher than the kickback for these two, but still lower than LF engines. 

Edited by Maxsimal

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Looks like I'll have to rework my stock shuttle soon. I've been planning to fly it again for a while now, but the SRBs were a big reason not to.

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Just now, Nebbie said:

Looks like I'll have to rework my stock shuttle soon. I've been planning to fly it again for a while now, but the SRBs were a big reason not to.

Another reason:

 

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