What to use for an efficient rocket

SynergyBoi

SynergyBoi

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#1
#1
So I have been launching rockets for like a week or two. I have this particularly large payload for my space station (the station is located at LEO). I tried using the launch system (made by me, if it is similar to other builds it's most likely a coincidence) that has been faithful to me (efficiently getting my previous payloads to orbit and docking) but it failed (looks like the payload's too heavy) when it comes to the payload I wanted to launch. Any ideas on how to improve my launch system? I use SLS 1.35.

By the way, here is my ol' faithful launch system for reference (without payload/fairings)
1602846835845.png
 
Cresign

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#2
#2
Can you show some pics?
 
TrenchRabbit

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#5
#5
I’m going to quote this from TtTotW

“Yeah. Look, for me personally, I never even exceed TWR of 1.33... Minimum 1.25. Also, I fuel my boosters to fall off at 10 to 18km. And my first stage is usually underpowered (TWR<1). The boosters push it up to 1.3-ish.

Second stage is TWR=1. Third stage is TWR=0.5 - 0.7. It is 50/50 mass split between S3 and payload. My rockets are generally one thickness throughout, except the boosters.”

65 tons isn’t a huge payload and it definitely doesn’t need that many hawk boosters.
 
Marmilo

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#6
#6
SynergyBoi said:
So I have been launching rockets for like a week or two. I have this particularly large payload for my space station (the station is located at LEO). I tried using the launch system (made by me, if it is similar to other builds it's most likely a coincidence) that has been faithful to me (efficiently getting my previous payloads to orbit and docking) but it failed (looks like the payload's too heavy) when it comes to the payload I wanted to launch. Any ideas on how to improve my launch system? I use SLS 1.35.

By the way, here is my ol' faithful launch system for reference (without payload/fairings)
View attachment 46833
Click to expand...
Ok, definitely use frontier for core stage. More fuel for the boosters. Apply rest to what TtTOtW said.
 
SynergyBoi

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#8
#8
CyprusRabbit said:
I’m going to quote this from TtTotW

“Yeah. Look, for me personally, I never even exceed TWR of 1.33... Minimum 1.25. Also, I fuel my boosters to fall off at 10 to 18km. And my first stage is usually underpowered (TWR<1). The boosters push it up to 1.3-ish.

Second stage is TWR=1. Third stage is TWR=0.5 - 0.7. It is 50/50 mass split between S3 and payload. My rockets are generally one thickness throughout, except the boosters.”

65 tons isn’t a huge payload and it definitely doesn’t need that many hawk boosters.
Click to expand...
By the way, I'm not so used to three-stage to orbit rockets, since my rockets are usually two-stage to orbit ones. But I'll try.
 
SynergyBoi

SynergyBoi

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#9
#9
CyprusRabbit said:
I’m going to quote this from TtTotW

“Yeah. Look, for me personally, I never even exceed TWR of 1.33... Minimum 1.25. Also, I fuel my boosters to fall off at 10 to 18km. And my first stage is usually underpowered (TWR<1). The boosters push it up to 1.3-ish.

Second stage is TWR=1. Third stage is TWR=0.5 - 0.7. It is 50/50 mass split between S3 and payload. My rockets are generally one thickness throughout, except the boosters.”

65 tons isn’t a huge payload and it definitely doesn’t need that many hawk boosters.
Click to expand...
65 tons is probably my biggest payload yet though...
 
Cresign

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Horus Lupercal

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#21
#21
Also, your core stage is too big.

If you want to lift 65 tons, here's a very simple method dude.

Take your payload weight.
Double it.
That is the mass of your second stage. Apply that amount of fuel tanks in any configuration you like and enough thrust so it has a positive TWR.
Then take that total and double it again.
This is your first stage mass. Place down that amount of fuel and apply engines until the TWR is slightly more positive.

See here for more details

https://jmnet.one/sfs/forum/index.php?threads/the-basics.2583/#post-44928
 
SynergyBoi

SynergyBoi

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#22
#22
Horus Lupercal said:
Also, your core stage is too big.

If you want to lift 65 tons, here's a very simple method dude.

Take your payload weight.
Double it.
That is the mass of your second stage. Apply that amount of fuel tanks in any configuration you like and enough thrust so it has a positive TWR.
Then take that total and double it again.
This is your first stage mass. Place down that amount of fuel and apply engines until the TWR is slightly more positive.

See here for more details

https://jmnet.one/sfs/forum/index.php?threads/the-basics.2583/#post-44928
Click to expand...
Hmmm. Seems good to me. So the second stage will be the same mass as payload? And first stage (maybe with boosters) will be twice of 2nd stage + payload?
 
Horus Lupercal

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#24
#24
SynergyBoi said:
Hmmm. Seems good to me. So the second stage will be the same mass as payload? And first stage (maybe with boosters) will be twice of 2nd stage + payload?
Click to expand...
Nyet.
The second stage needs to be double the mass of the payload. (So 130 tons by itself if the payload is 65t).
And yeah, the all up weight of the first stage (core + boosters) should be double that again.

This is just a rough guide. It's not the most efficient method of working it out, but it should get you to LEO on 2 stages.
 
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