GoSlash27

Kickn4fun, I concur with Scott Manley on that point; you should get lots of science early. What's biting you in the butt isn't the science, it's your design. Too light, lumpy, and draggy in the nose. That sort of thing used to work fine before KSP 1.0, but it doesn't anymore. That's why FullMetalMachinist has cautioned you about old "how-to" videos. Your rocket needs to be streamlined and have the center of mass high. You no longer do that "climb to 10km and go thataway" procedure, Asparagus staged "space pancakes" are no longer ideal. Your rockets now need to look like real rockets and your launches need to look like real launches. Have a look at this one: Best, -Slashy

Kickn4fun, KSP is all about "launch issues". That's it's charm. Imagine yourself watching a NASA launch on TV. They come to the 2 minute hold and show a pic of the rocket that's about to launch, and it looks exactly like the rocket you've posted here. Would you expect that rocket to make orbit, or would you expect it to lose control around Max Q? My best advice is this: Aerodynamics matters in KSP. Your rocket should look like something that would be successful IRL. HTHs, -Slashy

CSE, My approach is geared towards optimizing each stage for the DV requirement, not the optimal t/w. That's the "reverse rocket equation", outlined here: For t/w requirements, I use more crude "rule of thumb" figures. Atmospheric SRB first stage: 1.2:1 Atmospheric hybrid first stage: 1.3:1 Atmospheric liquid fuel first stage: 1.4:1 Launch transstage 0.7:1 Orbital insertion/ interplanetary stage 0.5:1 Vacuum lander/launch stage 1.5:1 local Of course, all of this is out of date now. I've been out touring Iowa on my blue scooter instead of playing KSP... Best, -Slashy

wumpus, Absolutely. As I understand it, they find the problems with clustered small boosters easier to overcome than the combustion instability problems associated with large boosters. Well... none of it is "simple". Every additional line is a potential source of failure. Changes in temperature affect the flexibility of the lines and each line has a resonant frequency. If a single line fails, it affects the mixture to every associated engine (or just nozzle) with catastrophic consequences. Basically it's a "pick your poison" kind of tradeoff. Best, -Slashy

I don't leave debris. Every staging event leaves the spent stage on a collision course. Best, -Slashy

^ This. Clustered engines also have issues with plumbing and potential shock wave interference. Best, -Slashy

Another one: You know you're a nerd when you can't restrain yourself from disassembling and reassembling things.

monstah, Likewise, there's no need to beef up DV. Having more DV than you need isn't actually an advantage. It's just more mass and fuel that you'll never use. Not an attack against the Twitch or Spider (I rarely find a use for either). Just pointing out that saying "You don't need all that t/w and this one has more DV" is every bit as misguided as saying "you don't need all that DV and this one has better t/w". The *proper* design philosophy is to have adequate t/w and DV in the lightest and cheapest package possible. Best, -Slashy

galactictaco, IK, R? I would never attempt such a thing myself without patched conics and maneuver nodes, but it has been done. There are some serious KSP ninjas around here... Yeah, I think that's a lost cause. You need some serious juice to hit Duna or Eve and the available hardware simply doesn't have the range even when spammed. Best, -Slashy

galactictaco, Yeah... interplanetary is out unless you go manned. Caveman communication tech simply isn't up to the task. We have had successful manned expeditions in the past and I assume it's still feasible. Best, -Slashy

@Shade Mourning, Yes. That will eliminate problems with both the center of lift and center of pressure (which isn't shown in the VAB). Additionally, you should make sure that the CoM doesn't shift as the fuel drains. It's a bit of a balancing act (no pun intended). Best, -Slashy

Quick 'n dirty design for 1t payload and stock parts: T3 stage: 1 Ant, 6x FL-T100. 2,840 m/sec @ .47g T2 stage: 1 NERV, 2xMk.1. 3,090 m/sec @ .5g T1 stage: 1 Poodle, 8xX200-8. 3,400 m/sec @ .5g OTS : 1 Skipper, 9xX200-8. 1,420 m/sec @ .7g Boost : 1 Mammoth, 8xS3-3600. 2,120 m/sec @ 1.4g This is enough DV to impact the sun or escape the solar system entirely. Best, -Slashy I hate when this happens. There's got to be a more effective way to signal people that they're commenting in a necro thread... Best, -Slashy

I believe the correct answer used to be "monkey", which is dumb because chimpanzees aren't monkeys. Best, -Slashy

^ This. Likewise, knowing the full and empty mass of a rocket as well as the exhaust velocity of it's engine, you can calculate the change in velocity ("DV") it will achieve. These two understandings of DV go hand in hand in rocket science. The simplest concept is above; "Delta means change, V stands for velocity. Hence, Delta-V = change in velocity". This is why it drives me nuts to see DV discussed without citing the units. Best, -Slashy

@Cunjo Carl and @JAFO, It has always been my position that such decisions should be left up to the clan, since we are all equals here. I personally have no problem with entrants having informational mods *so long as* they are not used to assist the challenge, and have taken people's word for it in the past. All of this is on the honor system, since there's no way to verify. Having said that... You might want to do another run on a clean install just to eliminate any doubt. I definitely prefer that such mods not be installed on caveman runs so that there are no questions. All of this is just my personal opinion. @MoeslyArmlis administers the challenge now, so it's up to him. Keep on bangin' those rocks together guys! -Slashy

Well... SRBs should only be used in the early going. They're very cheap and powerful, but heavy and inefficient. Not worth carrying any serious distance. Calculating DV with them is the same as any other rocket; the natural log of the wet/dry mass ratio times the exhaust velocity. When combining them with other engine types, the specific impulse is scaled proportionally to the mass flow rate. Most calculators should be able to calculate this given thrust and specific impulse of the engines firing in parallel. HTHs, -Slashy

Aegolius13, That is all true, and I can't really come up with any argument for not doing that. But in all honesty... I actually *do* throttle back during my ascent so that my thrust to weight is 2sin(pitch). I'm sure it's not doing me any favors in the efficiency department, but my gravity turns work out identical that way. I'm sure that running full throttle is more efficient overall, but IME throttling back tends to be easier. Laziness is the mother of invention, and I am nothing if not lazy Best, -Slashy

Well... Yes and no. More acceleration does save DV, but those savings can be misleading. DV savings don't automatically translate to fuel, mass, or cost savings. It usually works out lighter and cheaper to go with the numbers I posted above, even though the DV budget winds up being a little more. My first stage is always 1.2-1.4g off the pad and 1,800 m/sec DV calculated at 1/2 atmosphere. My second stage is always 0.7g initially and 1,700 m/sec DV calculated at vacuum. These numbers work out right for everything I launch with a reasonable safety margin. Best, -Slashy

^ This, about a million times. And most of the time, flying an overpowered rocket is more difficult than one with nominal thrust, not less. You only really need 1.4 off the pad (1.2 if using SRBs), 0.7 for transstage to orbit, and 0.5 for any transfer. Landers work fine with 2g in the local reference, which is tiny compared to Kerbin. Best, -Slashy

Thrawn889, Aside from the excessive DV for the job, I see way too much thrust, a lack of engine type optimization, and a lack of attention to streamlining. Also, asparagus staging isn't beneficial if not done correctly. A lot of what you're attempting could be done more simply and cheaply with a single stack. Generally speaking, you'll have better luck if your designs look more like real world ones. After all... real rockets look the way they do for a reason. Best, -Slashy

Thrawn889, Honestly... Your rockets shouldn't be costing you anywhere near that much. I recommend checking out this excellent tutorial by @Norcalplanner: Building a good airplane is more difficult and demanding than building a good rocket, and even more so for a cheap SSTO space plane. Whatever overengineering you've got going on now will be much worse in a space plane. I recommend that you focus on how to build cheap and efficient rockets first. Good luck, -Slashy

I don't use the Wheesley for anything. The Juno is fine for all of my low speed/ low altitude science in early career. By the time I need more performance, I've unlocked the Panther. Best, -Slashy

I don't balance my stages by mass, but rather DV. Boost stage is always 1,800 m/sec. After that, DV allocation is dependent on what I'm doing. 1,600 is good to get me just shy of low orbit if I'm incorporating a transfer stage. Otherwise I'll make it 1,700 to circ in LKO plus whatever DV I need to hit an intercept. The 1,800 m/sec figure for the boost stage (calculated at 1/2 atmosphere) is important because it burns out at the point where aerodynamic control and streamlining are no longer a concern; roughly 27 km on a nominal gravity turn. Best, -Slashy

If only this were true... The truth is, the engines haven't been balanced properly. There are some engines that are outclassed by similar engines so badly that they essentially have no role, and others that are so useful they are the best choice in many different roles. Every engine may exist for a reason, but that doesn't mean they're all useful. Best, -Slashy

Tweeker, I get that, Don't agree with all of it, but I get it, *But* since I don't design stages the same way you do, I find the Poodle incredibly useful. It's one of my most commonly used engines. Your mileage may (and clearly does) vary. Best, -Slashy