Norcalplanner

1. SRBs Any discussion of Cheap and Cheerful design has to start with SRBs. They're one of the cornerstones of C&C design. Here are my Rules of Thumb (RoT) for SRBs. RoT 1.1 - Use SRBs in your designs, but generally only as part of the first stage. SRBs are cheap for the thrust that you get. They're also heavy, and their vacuum Isp stinks. Use them where these disadvantages are minimized, which is the first stage. Sure, you can use them as a second stage, particularly early in career mode or when cheaply lofting a satellite into orbit; but generally, keep them on the first stage where they belong. RoT 1.2 - Use fewer, larger SRBs whenever possible. SRBs are more useful as they get larger. The Flea isn't good for anything, IMHO, other than providing a "holy crap what is happening" moment for new players the first time they launch a rocket in career. Hammer starts to get useful, BACC is definitely useful, and the Kickback is awesome. Not only does the cost go down on a unit of thrust per unit of time basis with the larger rockets, but mounting hardware costs stay the same - i.e., both the Hammer and the Kickback can be attached with a single radial decoupler, and possibly a nose cone. But one provides 227 kN of thrust for 24 seconds, and the other provides 670 kN of thrust for over a minute. Radial decouplers and nose cones are always justified for Kickbacks, sometimes for BACCs, and rarely for Hammers and Fleas. RoT 1.3 - Keep SRB costs low by taking advantage of surface attachment. SRBs are awesome in that they combine an engine and a fuel tank into a single surface attachable part. While it may take a little experimentation, it's entirely possible to create bottom stages made entirely out of SRBs radially attached to a center SRB or LFO tank, with the whole mess connected to the next stage via a single stack decoupler. RoT 1.4 - It's generally a good idea to tweak SRB thrust levels in the VAB. It's a rare occasion when it's appropriate to use an SRB full throttle. Generally you should tweak the thrust levels so that you have an appropriate initial SLT TWR (generally somewhere between 1.2 and 1.5, depending on a variety of factors). This may be difficult if you don't use MechJeb or Kerbal Engineer Redux to have accurate TWR info in the VAB. Another benefit of tweaking thrust is that it reduces the chance of overheating, which can happen when you're surface attaching SRBs. Rot 1.5 - Put a larger payload on top of an SRB-only first stage if you're having problems. Many players have tried using an SRB-only first stage. It can work well in early career, but things can be difficult once the BACC and Kickback are tried. One of the problems is the huge difference in TWR levels between a full SRB and an empty one. The solution is easy, but not entirely intuitive - put more payload on the SRB. If you don't have enough, you'll accelerate really quickly in the lower atmosphere, potentially with overheating and control problems. But if you give it a larger payload, TWR swings are minimized. - - - Updated - - - 2. Non-Part Mods Before I get any further, I think it's a good idea to talk about mods. I don't think anyone should hesitate to use mods which give you information which is critical to designing and constructing your rockets, or give you more flexibility in rocket design. With that in mind, consider the following mods. RoT 2.1 - MechJeb or KER give you useful TWR and Delta V readouts when designing rockets. This may seem obvious to most, but I'll come out and say it anyway - use KER or MechJeb for TWR and Delta V readouts when designing rockets. They form a critical part of the feedback loop during the iterative process of rocket design, instantly showing how the change you just made will affect rocket performance. Pay special attention to the Sea Level Thrust (SLT) TWR number for the first stage or two to make sure you've got a design which is going to get off the pad. RoT 2.2 - Editor Extensions gives you a lot of options in design. While it's possible to eyeball things, wouldn't it be better to hit a key that will automatically center a part vertically or horizontally? Wouldn't it be great to do 7-way symmetry if that's the exact number of SRBs you need? Wouldn't it be great to do angle snap at a bunch of other angles besides 15 degrees? Editor Extensions does all of this. Seriously - if you're into rocket design and want to build things precisely, get Editor Extensions. RoT 2.3 - Kerbal Joint Reinforcement will not only make your rockets more solid, it will reduce your part count and increase rocket and game performance. I know that KJR was occasionally buggy in the past, but all the kinks appear to have been worked out now. While making rockets more solid is always appreciated, I think it's just as helpful in reducing part count, particularly struts. Reducing the part count reduces cost, drag, and the load on your CPU when flying the rocket. KJR is a C&C builder's friend.

Welcome to my first-ever tutorial thread. I've picked up a lot of knowledge and formed some definite opinions about KSP ever since I started playing back in 0.23.5. I thought it was time to give back to the community and let others profit from my experience. What is Cheap and Cheerful? Cheap and Cheerful (hereinafter abbreviated C&C) is what I've come to call my philosophy for cost-effective rocket design in KSP. It's based on a British idiom for “something that is costing little money but is attractive, pleasant, or enjoyableâ€Â. Another definition is “not of bad quality, or otherwise enjoyable, despite being cheapâ€Â. When looking at payload fraction and cost per ton to orbit in KSP, the smart crowd tends to gravitate toward SSTO space planes. They make a lot of sense, if your temperament is compatible with their design and operation. But it takes longer to get to orbit, your ascent profile needs to be closely managed, and designing a craft which is stable and controllable throughout the flight profile (ascent, descent, with cargo, without cargo, full tanks, empty tanks) can be an exercise in frustration for those not well-versed in KSP aerodynamics. The best space plane parts aren't available until relatively late in the tech tree, and the funds investment per craft can be quite high. The cargo bay dimensions limit the size of what you can lift with a single craft. Recovery economics dictate that you have to land fairly close to KSC and in one piece. There has to be another way - dare I say it, an easier way. Enter Cheap and Cheerful. C&C is about rockets - practical rockets that exist at the intersection of cost, capability, part count, ease of operation, and tech requirements. Building a rocket that has almost as much capability as an optimized design, while having a lower part count and costing a fraction of the funds – this is the C&C way. In the entries to follow, I'm going to set forth what I've learned in a number of "Rules of Thumb" for doing things the C&C way. Those wanting pretty graphs and detailed analysis may be disappointed. Healthy debate and alternate viewpoints are welcome. Snarky comments and trolling are not. While the majority of the discussion will be about lifters, we'll also talk about other types of craft. To demonstrate what I'm talking about, I've inserted below the namesake Cheap and Cheerful lifter which was the inspiration for this thread. It was a 1.0.2 entry in Red Iron Crown's payload mass fraction challenge, and got 20.9 tons of inert payload into LKO. The entire rocket, including payload, was 36,775 funds, while still getting over 20% payload mass fraction to orbit. Please note that this tutorial is intended for those who already know the basics, and have successfully landed on the Mun or Minmus and returned. If you're still struggling to get to orbit, other threads may be more helpful. Also, this thread is going to be a work in progress for at least the next few weeks. I'll add new posts with additional Rules of Thumb (RoT) on a quasi-regular basis regarding different aspects of KSP rocket design. If anyone has questions regarding a particular topic I haven't covered yet, feel free to chime in and I'll do my best to get to that topic sooner rather than later. Similarly, if anyone needs more/better/any illustrations for a particular concept, let me know and I'll do my best to provide pretty pictures to help explain these concepts. Table of Contents 1. SRBs 2. Non-Part Mods 3. LFO Engines 4. Electrical 5. LFO Tanks 6. Aerodynamics 7. Command and Control 8. Docking 9. Stage Recovery Exotic Propulsion Discussion Examples 200K Fueler Docking Port Attachment/Orange Tank Refueler Double Orange Tank Refueler

Slashy, where would you say the lines cross? Certainly if you're up in orbit around the Mun or Minmus, it makes sense to do what you're talking about. What about something that's just a little higher than LKO, like my favorite fuel depot orbit of 250 km? How about 400 km or 600 km? Is it still worth doing a retro burn first, then burning at Pe from these orbits? My gut says no, but I'm very open to being wrong.

OhioBob, this is great information. It shows that I haven't been completely off my rocker by putting a refueling depot at 250 km to top off interplanetary craft. One question - how do steering losses affect this? One of the reasons I've been doing higher orbits is to minimize those losses and still be able to do a transfer burn in a single orbit.

Just in case anyone wants to give it a go, I've uploaded the Herkules onto KerbalX. You can get it here.

So I just signed up at KerbalX. Hopefully you can find and download the craft here.

They're tweakscaled.

So I went ahead and did an entry with LFO. Ended up going with classic 2x2 asparagus staging with 5 Mainsails and 6 Kickbacks. Ended up with 2.08 white tanks worth of fuel in 90 km LKO for just under 200K funds. More description in the pics.

So it's just LF you need? Do you need any oxidizer or monoprop at all?

How much fuel do you need? I just slapped together a rocket using a Mainsail and 4 Kickbacks that can take up 1.25 orange tanks of fuel with a Poodle attached, and drop it off in a 90 km orbit, for less than 60K funds. Do it three times and you have 3.75 orange tanks in orbit for 180K funds. How much fuel do you really need?

What you're talking about is known as a Grand Tour. I'm aware of at least four people who have done such a tour without refueling, all documented as part of the original Jool-5 challenge. Click on this link and scroll down to where one of the leaderboards reads "Jebediah's Level + Grand Tour". All of these were in earlier versions of KSP making extended use of massless parts, so weight will be more of an issue. On the other hand, aero is better, so maybe it balances out a bit.

This. If all you want is a fuel pipe, this is the way to go. KAS & KIS are overkill unless you're using them for other things as well.

As indicated in the OP, RL time pressures and family health issues require that I curtail my KSP time. I'll still be around, but it will be on a irregular basis. So that people won't have to wait for a week for an answer regarding a rule or to get their entry scored, Glaran K'erman has graciously volunteered to keep the challenge running in my absence. Please direct all routine inquiries to him. Thanks Glaran!

I think my Mun Rocked Challenge entry is my biggest stock craft. No KJR, so I had to use many, many, many struts. 12,513 tons on the pad to launch a monster lander that was 1,287 tons when it set down on the Mun.

Congratulations, purpleivan! You have completed the Grand Orbital Space Station Challenge with an entry scoring 77,243 points! A very nice-looking station with some tasteful lighting shown off in a lot of well-composed photos. Efficient use of the Mk3 parts for maximum Kerbal count with minimal part count, although your homemade extra-powerful RCS block probably pushed the part count up a bit. And I like how each module can detach and still make it back to Kerbin with the heat shield and all the parachutes. The only question in my mind is what category to put it in - it looks fairly stock, but the strut count is a bit low without using KJR, which would push you into the modded division. Please let me know if you used KJR, part welder, or any other mods which would push your entry out of the stock(-ish) division. Feel free to add the badge to your sig, and thanks for participating in the challenge!

Purpleivan, Just glancing at things, this looks good. Due to RL commitments, it may be a day or two before I can review your entry in detail. And just to clarify, it's fine to move your station elsewhere to obtain a higher score. The majority of my stations have enough tankage and engines to move around a fair bit.

I think if the sentiment is modified slightly to "maximize the time doing what you find fun in KSP, and minimize the time doing what you find tedious in KSP" then it makes more sense. Speaking solely for myself, I can spend hours in the VAB working on a design, launching, reverting, tweaking, launching again, etc. with no real goal other than to refine my design for whatever metric I'm using at the moment, be it cost, capability, or part count. That's one of the reasons I do some of these crazy challenges that seem not to have any immediate application. Getting back to the original question, use spaceplanes if you enjoy spaceplanes. Use something else if you don't. But I guarantee you'll learn even more about aerodynamics and spacecraft design even if you just do a little bit with spaceplanes.

Explosive staging can work. Who knew?

Meet the Herkules, the slightly bizarre brainchild of one Howard Kughes. He told his engineers to make a lander that would be at least a thousand tons when landing on the Mun, and they came through. Final landed stats on the Mun are 1,287 tons and 206 parts. Full info is in the descriptions of the photos.

Grrrrrr... Imgur is not cooperating. I'll try again later.

The Herkules has successfully landed. Pics and more info later tonight.

That's what I had figured - no need to apologize. After barely making it to orbit due to my second stage engines not gimballing, I will be installing Claw's stock bug fixes. I don't even want to think of what landing this beast will be like if I have to rely solely on reaction wheels during final descent.

Congratulations, rudi1291! You have completed the Grand Orbital Space Station Challenge with a Stock(-ish) Division entry scoring 42,500 points! Thanks for putting up the additional photos. Some of the Delta V figures seemed a little off, but I know from experience that sometimes KER or MJ gets confused by creative staging. A very impressive mining station, suitable for refueling a veritable armada of craft. I hope that you have some major colonization efforts going on to make good use of the setup. Feel free to add the badge to your sig. If you enjoyed the challenge, rep is always welcome. Adding you to the leaderboard...

I have eleven different installs, but am only currently playing 1.0.4 in several different variants - stock, lightly modded, heavily modded, BD Armory, and RSS/RO.

Interesting challenge - I may have to give it a try. Just to confirm, I need to go buy a gross of struts because KJR isn't allowed, correct?