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Realism Overhaul Help


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I've gotten stuck in career mode (RSS, Realism Overhaul, RTT Lite tree) and I can't seem to make a rocket good enough to get into orbit without strapping a ridiculous amount of liquid cores onto the side (usually 6+ doesn't cut it, SFJB Real Engines in use by the way). What are the engines with thrusts below 100 kN even good for anyway? I can hardly even get a light payload up to 3000 m/s with my first stage, let alone push it into orbit with a TWR of .26. Also, getting a rocket to have 12000 m/s of delta-V, barely enough to reach orbit, requires something the size of Saturn V at the moment. What's the most optimal way to design spacecraft?

Edited by Bluechance
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I suggest using FAR (If you're not already) and beginning your gravity turn as soon as you clear the tower, it should be gradule, not the burn-to-10km-pitch-to-45-degree nonsense of stock, especially with RSS. I am not expert but the engines with thrust below 100kn are good for orbital maneuvers as they are generally more efficient. Also, are you using the suggested Real Fuels mod? That might help with getting more bang for your buck. you might also try KIDS (Kerbal Isp Difficulty Scaler) which will change the values of stock parts to better fit with RSS.

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yea, I'm using FAR and Real Fuels. Also on a side note, is there anyway to help reduce G forces for capsules on suborbital flights? My little rocket I just tested made it to about 5700 M/S before running out of fuel, the resulting G forces on descent killed my crew.

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Alright, so how large is the service module that you're sending up with this capsule? If you're just starting out, send it up with a small amount of RCS for maneuvering and maybe 300 m/s of dV for final orbit adjustments and deorbiting. This payload shouldn't be more than 15 tonnes.

Then build an upper stage. Find a hydrolox engine designed for orbit (either a J-2, J-2x or a cluster of RL-10s) and set that stage up with 2.5 - 3.5 km/s of dV. It's initial TWR needs to be ~0.6 to get to orbit.

Then build your core stage. Find either a higher thrust hydrolox engine (RS-68A is good for thrust, RS-25D is a little lower but better efficiency) or a good kerolox engine (if you have Bobcat's Soviet Engines a few NK-33s or one of the RD-171s is good for this). Set it up with enough dV to give you a total of ~9.5 km/s; your TWR will end up below 1, but this is fine, since we're going to add boosters.

Then, slap a pair of radial decouplers on and attach StretchySRBs to that. Set them up with decent Isp and a burn time of about 1 - 2 minutes. Increase the size until you get a TWR of 1.6 - 1.7 vacuum (or 1.4 - 1.5 SL). Attach nosecones and sep motors.

Set up the staging and try that; you should have lots of margin. You don't need 12 km/s to reach a 300 km orbit unless you're spending a lot of time burning off prograde. Even then, you can reach a 500 km orbit, doing a 30 degree inclination change in the middle of the orbit with only 10.5 km/s. Trust me, that's all it takes/.

As for the lower thrust engines, if you're only thinking in terms of things that weigh 30 tonnes and up, yeah, they're not that great. But if you're working with probes, they're great; that mission above had a final stage that only made 14.3 kN of thrust, but it gave the stage + payload a TWR of 0.3 (initially). The stage before that was a vacuum SRB that made 198 kN and that gave me a TWR of 2.5. You're probably just building payloads that are too large.

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The only problem I have with the stretchable SRB's and super-stretchy tanks is that they're stuck at a ridiculously low width for some reason and they won't widen out any. I think it's probably the work of the RPL tweaks, but I have no idea how to get around or solve the issue.

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The only problem I have with the stretchable SRB's and super-stretchy tanks is that they're stuck at a ridiculously low width for some reason and they won't widen out any. I think it's probably the work of the RPL tweaks, but I have no idea how to get around or solve the issue.

Hold down F and move the mouse. Also make sure you're usings the super stretchables.

ferram4 gave a really good explanation :)

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Oh, you don't have enough stuff unlocked to actually build manned orbiters then. You're going to have to stick to probes until you get more science to put into the liquid and solid rocket techs. Or go full Saturn 1B and just build a single stage out of clusters.

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