Norcalplanner

wumpus, Not sure about Kerbal Engineer on the TWR readings - I've been using only MechJeb for the last few months. When I'm going for optimal delta V design, I'll use that 1/4 rule that you're talking about. The staged LFO probe that was mentioned as part of the exotic propulsion discussion uses just such an arrangement, consisting of an FLT-100 with an Ant, on top of an FLT-400 with a Spark, on top of a Rockomax 16 with a Terrier. All those stages have approximately the same delta v, just like you said. I think what I was trying to say with that rule is that if the bottom stage is a Mainsail, it's better for the next stage to be a Poodle than a Skipper. The Skipper would be more appropriate on top of a Twin Boar or a Rhino. For a stage on top of a Skipper, I'd go with the Big Impulse 120 kN orbital engine from Randazzo's Vanguard VX engine pack, mentioned earlier, since a Poodle would be too big and a Terrier too small for the rule. I'd agree that there's lots of room for different designs which can all work. Recovery is a whole other kettle of fish, which I'm now convinced needs its own entry as part of the Cheap and Cheerful discussion. Essentially, you have to decide what resources are most important to you, both in-game and in real life (such as your patience and time available to play the game). I discussed this a bit in a previous response - I'll come up with something that weighs the pros and cons of different levels of recovery and distills them into a few Rules of Thumb. Thanks for the observations and for the real life Rules of Thumb regarding rocket stage mass and delta V. - - - Updated - - - Yep - definitely need to have a discussion and Rules of Thumb for various levels of recovery. Maybe that could be a challenge - lowest cost to orbit for various categories of rocket recovery - SSTO, SSTO with disposable SRBs, and disposable staged. Still need to think about that some more, especially since I got burned out on running my other challenge. - - - Updated - - - While I agree, I don't think everyone would. I'll fold this into the recovery discussion, which hopefully will be ready in a day or two.

Slashy, Thanks for your comments. I look forward to seeing your lifters. Seeing how other people do things can result in a healthy cross-pollination of ideas and techniques. I agree that a Cheap and Cheerful lifter should always have SRBs in the first stage, but I'm a bit hesitant to say that it should "always and only" be SRBs, if I'm hearing you correctly. Part of the Cheap and Cheerful philosophy does include an ease of use factor, which is one of the ways it contrasts with the use of SSTO spaceplanes. (And yes, I feel moderately embarrassed to be saying this to one of the best SSTO spaceplane guys on the forums.) We'll definitely need to include some examples of differential thrust limiting in launchers to manage TWR. I tend not to do it too much, but I have used it occasionally. An SSTO rocket is generally the cheapest way in terms of cost, but the recovery time and skill required to "close the loop" and make it pencil out compared to a cheap disposable rocket means that it's not going to be everyone's cup of tea. I did it a couple of times, but it always involved a precise reentry profile, a powered final descent in addition to parachutes, and landing on engine bells. It was a bit too nail-bitey for me to do on a regular basis. I think I need to write an entry regarding the different spots on the Cheap and Cheerful continuum, noting how there are frequently tradeoffs which need to be made based on the player's available time, patience, and piloting skill in addition to things like cost and part count. I also have some vague ideas running around in my head regarding a challenge, but it's been done many times before and trying to come up with "Cheap and Cheerful" rules that don't quash creativity would likely be difficult. - - - Updated - - - Starhawk, Good observation. I think some players (hopefully not many at this point) still put small tanks on the bottom because of the old issue with orange tanks overheating. I'll either add your point to the LFO tank discussion, or fold it into the future post I'm formulating about rocket geometry. This is one of the reasons I love Fuel Tanks Plus, by the way - because it has tanks like the Rockomax 128 (a double-length orange tank as a single part), it's much easier to have the rocket maintain a desirable CoM during ascent. This is in contrast to the frequent problems with rockets becoming bottom-heavy due to the fuel flow rules when using stacked tanks in the first stage.

Lots of good points here in the last few posts. I'll respond as soon as I can, which will probably be later tonight.

Thanks for the feedback, Meithan. Love your chart app, BTW. Honestly, I've only used linear ports once, and that was a long time ago. But now that I'm looking at the stats and thinking about the geometry, I think there could be a scenario where they would work. If you had sufficient rotational control authority via reaction wheels, then four ports placed around the CoM should give adequate translation ability. You could use the main engine on the craft to thrust forward, and would need two symmetrical ports on the front of the craft, on either side of the docking port, to slow down and reverse. The six ports would give the same translation authority as four of the multi-directional ports (one port at 2 kN vs. two ports at 1kN each) at a slight savings in cost (1680 funds vs. 2480 funds) and weight (0.18 tons vs. 0.20 tons) but with two more parts. My gut tells me that wobble will be a bigger problem if the ports aren't right over the CoM. I'll need to test this in game before deciding if it's a good or bad idea. I may have to also try my other oddball RCS idea - that it's possible to dock a craft using only two multi-way RCS blocks. Since you'd only get translation in one axis, you'd have to rotate the craft around its long axis to align the thrusters with the needed translation vector for every correction. Sounds a bit crazy, but I bet that Jeb would be up for it. If he can get it to work, it would be the cheapest, lowest weight, and lowest part count solution for RCS-assisted docking.

There's some good discussion here which tracks very closely with my WIP tutorial, Rules of Thumb for Building Cheap and Cheerful Rockets. If any of you fine folks wanted to go over and provide some constructive criticism or alternative viewpoints, I'd greatly appreciate it.

Double Orange Tank Refueler Example "But Norcal, my ship needs two orange tanks worth of fuel. How can that be done in a Cheap and Cheerful way?" Funny you should ask. Meet the Double Orange Tank Refueler. The basic Orange Tank Refueler design is tweaked to add another orange tank to the payload, and 5/8 of an orange tank of fuel to the lifter. Oh, and one little detail - eight more Kickbacks are surface attached to the existing four, making a total of 12 SRBs in the first stage. Remember, SRBs are cheap. This example gives fuller expression to many C&C design principles, effectively doubling the payload for only a 61% increase in cost. More information is in the descriptions.

Docking Port Attachment Examples Here are some photos of how to use docking ports in a manner similar to decouplers. While there are advantages to doing things this way (including the fact that 1.25m docking ports are lighter and cheaper than 1.25m stack decouplers) I don't recommend using them for anything which will be separating while under power and/or in atmosphere, such as with a lifter. Not being able to activate them as decouplers through the standard staging sequence can have calamitous unintended consequences. - - - Updated - - - Orange Tank Refueler Example Here are some photos of a refueler with enough hardware to either be a passive depot or an active tanker going to a craft which is out of fuel. Includes a demonstration of how to figure out where to place a single group of four RCS thruster blocks around the CoM of the craft.

Waxing_Kibbous, Thanks for the kind words. I'm glad you're finding the thread helpful. I should have some more examples posted later today which show how to use docking ports as you describe, among other things. Once all the entries are complete, I'll likely reorganize things a bit. Converting to PDF is a definite possibility. However, I think I still have a few more entries to make before taking those final steps.

Example - Small Science Satellite Here's a small satellite that follows C&C design principles. It's essentially a Terrier-powered single-stage craft that needs an SRB for the initial kick. Lots of information is in the descriptions. Please note that this is only meant to demonstrate one way of doing things the C&C way. It is by no means the only way.

I made this Skipper-powered craft for a discussion in a different thread, but it's still meaningful for this discussion as well. Skipper plus two thrust-limited kickbacks equals 18.9 tons to LKO for 1,089 funds/ton. P.S. Red Iron Crown, love the pic - I just wish those mods didn't slow my system down so much.

Passinglurker, Lots more good questions. Since Cheap and Cheerful design tends to be part agnostic (i.e., it's a philosophy for making the most cost-effective and practical use of whatever parts you have available), I don't want to delve too deep into responses for fear of turning this thread into a part balance discussion. However, I can answer in a few generalities. I don't think small craft ever need RCS ports, since existing reaction wheels provide sufficient control authority for less cost and the magnetic docking ports have a wide tolerance for slightly-off approaches for lightweight craft. I don't think xenon is obsolete, it just has a particular niche that it fills that perhaps isn't as large as many people thought. Docking tugs can be economical, depending on the amount of docking you're doing. The trick is being able to deal with the asymmetric RCS thrust during translation. I tend to not use them that much because I'm comfortable launching very large payloads that require minimal docking - for example, I launched this 700-ton station in two pieces, so there was only one orbital docking maneuver to make. If you're using a spaceplane for construction of an orbital station or have otherwise placed some restrictions on your rocket design so that you'll be bringing up more numerous smaller modules, then go ahead and include a tug. Otherwise, fewer larger launches using cheap SRBs can result in a lower total cost and part count for a station. Regarding parts becoming obsolete, I'm OK with that. It gives the player something to shoot for with larger/better parts. That said, I nearly always play with SpaceY, which includes a more powerful 1.25m engine, 0.625m SRBs, 1.875m SRBs, 2.5m SRBs, 5m LFO engines and tanks, and other goodness. In terms of filling in the gap in capsules, I'm also a big fan of Nertea's mods, including Near Future Spacecraft, because it includes a Gemini-ish 2-Kerbal capsule that weighs less than the stock 2-kerbal lander can but has better reaction wheels and heat tolerance. There are also a small number of nice engines in Randazzo's VX Series Vanguard Engines pack, including a 40 kN 1.25m vacuum engine and a 120kN 2.5m vacuum engine which I use all the time. RL beckons, so I have so sign off. I should be able to post some more example craft later today.

Fuel Tanks Plus will give you a wide selection of fuel tanks, including many which can be set to be LF-only. For extra nuclear goodness, load up MRS Lite and use the quadnuke, a 2.5m LV-N with four times the weight and four times the thrust in a single part.

Passinglurker, these are all good questions. Regarding exotic propulsion, I think these are very different cases. I'm not aware of any scenario where it would make make sense to use a monoprop engine in a stockish game, but I'm not familiar with some of the hybrid monoprop/electric engines that I just saw are in RLA. For ion, it would depend on the total delta V requirements and the cost of the payload. Once you have 50,000 funds worth of instrumentation on a probe, the difference between 2,000 and 20,000 for the drive section doesn't seem to be as large. In terms of pure efficiency, I think you would need to be doing a multi-year, multi-planet probe flying a flight path that requires more than 8,000 m/s of delta V for an ion drive to start to make sense. Essentially, you would need to look at how much it would cost to achieve the same science objectives using one or more chemical rockets and whether or not you can recover the instrumentation anywhere near KSC after the end of its flight. The initial cost difference in lifting a 1 ton ion probe vs. an 8 ton multi-stage LFO probe isn't all that great, but the chemical one would require more engines and decouplers, which drives up the price a little bit. Nuclear really comes into its own when there's a large payload involved. Without a payload, an FLT-800 with a Terrier has approximately the same delta V as an LF-only tank of the same size being pushed by an an LV-N, and the Terrier setup is 1/8 the cost and 2.5 tons less to orbit. Once you start adding larger payloads though, so that the greater weight of the LV-N ceases to be such a disadvantage, then it makes more sense to go nuclear. This is especially true if it's a station or mothership that is going to be used for many missions. I just did a quick test - five LV-Ns pushing an 81-ton payload required a 40-ton LF tank to have over 2,000 m/s of delta V. The same solution using LFO and a Rhino required over a hundred tons of LFO tankage for the same Delta V. The nuclear solution was 27,000 funds more, but it would cost more than 27,000 funds to loft the additional 60 tons of LFO tanks, so a nuclear solution is superior in this scenario. One thing I would add is that the nuclear TWR was only 0.23, and would need to use multiple periapsis kicks if it was doing a transfer to Jool, whereas the Rhino could do it in a single burn. Of course, if you have a good mining and refining setup and can refuel things in orbit cheaply, then things change again, and not in entirely predictable ways. On RLA, I've only ever used that mod as part of RSS/RO, so I don't know its strengths and weaknesses in the standard Kerbal universe. Give me a few days to play with it and I should be able to form an opinion. Regarding balance issues, I agree that using and abusing docking ports is gamey, and I wouldn't do it in a RP situation (such as my Apollo Applications Program save for that particular challenge). In terms of balance, it seems to me that the easiest thing would be change things so that that docking ports can only connect to a decoupler, stack separator, or another docking port. I'd also look at increasing the price of the 1.25m docking port so that it's not significantly cheaper than a 1.25m stack decoupler. Are there any other hacky tricks you're thinking of? Thanks again for all the great questions. I'll see if I can get you an answer on the RLA issue sometime soon. Addendum - After doing some testing with LFO probes and ion probes, including the cost of their respective launchers, I've been able to refine things a bit. If you've unlocked the entire tech tree, then it makes financial sense to use an ion-powered probe if your flight plan needs more than 9,000+/- m/s of delta V and you can make the whole thing work with only solar panels and batteries (no fuel cells). Otherwise, it's better to use a multi-stage 8- to 10-ton LFO probe. I would also note that the parts for the LFO probe are available earlier in the tech tree, that it has better TWR than the ion probe, and has better burn capabilities out past Dres. In terms of lifter cost, the LFO probe's lifter costs $15K, while the ion probe's lifter costs $4K. The entire ion probe rocket (including lifter) is $3K more expensive than the LFO probe rocket, but the ion version had 500 m/s more delta v. Addendum No. 2 - After playing around with RLA a bit, I've come to some conclusions: 1) whoever made the mod really loves probes and monoprop; 2) there's some overlap with SpaceY in terms of 0.625 meter fuel tanks, RCS thruster blocks, and SRBs; 3) there are some nice probe cores that fill out the range a bit; and 4) several of the monoprop engines seem OP compared to stock. Because of the lower empty tank mass fraction of monoprop compared to xenon, and the much lower price of monoprop, several configurations I tested with hybrid electric/monoprop engines were superior to xenon at a lower price. However, even the straight monoprop engines had a very high vacuum Isp (340) compared to stock. On the whole, I'd say that the straight monoprop engines are slightly OP, and the hybrid monoprop engines are much closer to Near Future Propulsion than they are to stock.

8. Docking Docking is simultaneously one of the most challenging and rewarding things for a new player to master. It allows landers to depart from and return to orbital motherships or stations, the transfer of personnel, and the transfer of fuel and resources. It also allows the player to assemble craft in orbit which would be difficult or impossible to launch with a single rocket. Here are the Cheap and Cheerful Rules of Thumb for docking and docking ports. RoT 8.1 - Stick with the standard docking port. The standard 1.25 meter Clamp-o-tron docking port should be your mainstay port. It's the cheapest and the second lightest, and provides enough strength for most docking jobs. It should be the only docking port for the majority of your craft. Only use the smaller ports if they're intended for a very small 0.625 meter probe, where every ounce counts, and only use the large ones for assembling large stations and motherships. Both other port sizes are significantly more expensive. RoT 8.2 - Only put thruster blocks on craft which are a) going to dock and undock, and weigh more than 2 tons. Smaller probes and landers can get away with not having any RCS thruster blocks - it's just a matter of zeroing out relative velocity between the two craft using the main engine, then having each craft point its docking port at the other craft's docking port. If you're slightly off and wobble a bit before locking on, then that's fine - the mass and cost savings for not putting RCS blocks and tanks on your small craft is well worth the extra docking effort. RoT 8.3 -Try to use only a single group of four RCS thruster blocks. If it's possible to do so, figure out what the most likely fuel load will be during a typical docking maneuver for a craft, then put only a single group of 4 RCS blocks around the center of mass for that fuel load as shown in the VAB. Yes, you may get a bit of wobble every now and then, but you've saved 2,480 funds and four parts by having only a single group of thrusters. Only put on a second group of thrusters if you're having trouble with a lot of wobble, or will be docking with vastly different fuel states. Also note that the location of the RCS blocks does not matter for a craft that is only pushing back - in other words, don't worry about having RCS thrusters near the "full tanks" center of mass for the craft. Location only matters when translating, not going forward or backward. Also consider deliberately placing the RCS blocks off center if it means that they'll be on the part of a craft which will be recovered. RoT 8.4 - Don't use a monoprop tank unless you have to. If you do need one, use a single inline tank. Most manned capsules carry enough monopropellant on board to dock and undock at least four or five times, so long as you're using proper docking technique. Only add monoprop tanks if you don't have a manned capsule, or if the manned capsule is on a massive craft. Also note that certain docking ports also contain monoprop, such as the stock Mk2 inline docking port, as well as some mod docking ports (such as those in Nertea's Stockalike Station Parts Expansion mod). If you do decide you need some additional monoprop, use a single inline tank. Yes, it won't look as cool as that ring of smaller radial tanks, but the inline tanks cost less per unit of monoprop, have a better full/empty mass ratio, and result in a lower part count. RoT 8.5 - Use them as decouplers, where feasible. Anything with an axial attachment node can be stuck to the "out" side of a docking port, and then be detached one time while in flight - just right click on the port, and choose "decouple node". They can be used as cheaper stack decouplers, so long as you disable crossfeed so you don't accidentally drain your upper stage tanks. They can also be used to temporarily attach smaller craft or satellites which won't reattach (such as resource scanning satellites attached to an orbital station going to a distant location). I've also planted satellites with a docking port on top upside down on a radial LV-N stack, just as a convenient place to park the satellite as part of the launch that will already be underneath a fairing. One of my favorite uses is to make a satellite with a docking port on top, then send multiple stacked versions of the satellite to a distant location as part of a single craft (such as two satellites to Duna/Ike, or six satellites to Jool). RoT 8.6 - Check out SpaceY for even bigger docking ports and RCS blocks. SpaceY is another mod by Necrobones that contains a number of large rocket parts, including 2.5 meter SRBs and 5 meter LFO tanks. For docking, the critical addition is the inclusion of 3.75 meter and 5 meter docking ports. It also has a number of powerful RCS thruster blocks. If you're looking at joining some truly massive things together in orbit, check out SpaceY. When used in combination with Kerbal Joint Reinforcement, you can have some very large, solidly constructed craft with very few struts. - - - Updated - - - Pause for Q & A At this point, I think the next step is to clean up the format of what I've got and put in a table of contents. After that, the plan is to start putting up some some sample C&C craft for typical scenarios (and hopefully posting them all to KerbalX) to show how all this fits together. The idea is to have a tangible visual reference for reference and discussion craft for different mission profiles. Before I do, does anyone have any questions, comments, feedback, or alternative viewpoints? I'd like to make sure that I'm explaining things clearly enough, and answering questions that you actually have, rather than questions that I think that you have.

Skipper was the best in 0.25, back when it had an Isp of 320 / 370. In 1.0.4, it's a 3-way tie between the Mainsail, Poodle, and Terrier.

SpaceY has 3.75m and 5m docking ports that are even stronger.

7. Command and Control Every rocket needs some means to control it, either a probe core or a manned capsule. There also needs to be a way to translate those control inputs into motion in the craft, whether through dedicated reaction wheels, RCS thrusters and monoprop, or integrated reaction wheels in a probe core or capsule. Here are the Cheap and Cheerful Rules of Thumb for Command and Control. RoT 7.1 - Use only the OKTO and RC-001S probe cores. The OKTO should be the only core you ever use on small probes. It's available early in the tech tree, gives you basic SAS capability, is cheap, is light, and has a small integrated reaction wheel. If you're using MechJeb, then SmartASS provides all the capability (holding prograde/retrograde, etc.) of the more expensive probe cores. The only time you shouldn't use the OKTO is when you really need the 1.25m form factor, such as on the front of a manned capsule and/or beneath a docking port. In those cases, use the RC-001S. The only other probe core you should even consider is the RC-L01, and then only when the craft needs the 2.5m form factor (such as being inline close to the center of a space station). RoT 7.2 - Use only a single 1.25m or 2.5m reaction wheel. The smallest (0.625m) reaction wheel has a strength of 5. The 1.25m reaction wheel has twice the mass and cost, but triple the strength (15). The 2.5m reaction wheel has twice the mass and strength of the 1.25m wheel, but less than twice the cost. Avoid using the tiny reaction wheel, and stick with the medium and large diameter versions, assuming that you need one at all. Try to use only one whenever possible. Yes, you can break this rule for something big that you're going to be interacting with a lot, such as a Jool mothership weighing several hundred tons. But for most craft less than 75 tons in vacuum, a single reaction wheel will give you sufficient attitude control while minimizing part count, cost, and mass. RoT 7.3 - Don't use RCS for attitude control. RCS costs mount quickly - four of the standard RCS blocks cost 2,480 funds, and will go through a finite resource (monoprop) that you have on board. Save the cost and part count, and only put RCS on craft that will be docking. And remember to empty any monoprop out of your capsule in the VAB if you're not going to use it. RoT 7.4 - Stick with the Mk1 Command Pod as long as you can stand it. The first capsule that you get is the cheapest. It's also tied for the highest heat tolerance, is the second lightest, and is somewhat aerodynamic. Use it on as many craft as you can for as long as you can. If you need a standard size docking port on top, then move up to the 1-man lander can. Once you do decide to move to a 2- or 3-person capsule or cockpit, they're all markedly inferior in one way or another. Use the Mk1-2 if you're going to be doing a high-speed reentry, and the 2-man lander capsule for vacuum operations and gentle LKO reentries. The 2-man lander also presents some unique opportunities due to its form factor, as it's the only stock capsule or cockpit that can have a Sr. docking port on top.

Time for an Example I still have a few areas to cover, but I thought it might help people to see a number of these concepts put into action with a real rocket. This is the 200K Fueler Mk11. I made it for a challenge to see how much fuel I could get to a 90 km orbit with a rocket using only stock parts and physics for less than 200k funds. The craft is available on KerbalX if you want to try it out. Note that this design includes struts because KJR was prohibited for the challenge - normally I'd use KJR, omit the struts, and see if I can use the savings in cost and drag to increase the payload. Just to walk through some of the design decisions: Although it's an asparagus design, it only uses 2x2 staging to minimize the total number of stacks. All five LFO engines are Mainsails at 13,000 funds each. All six SRBs are Kickbacks at 2,700 funds each. Each radial stack is the same diameter as the engine. Each Mainsail has at least 2.75 orange tanks worth of fuel stacked on top of it. Each stack uses a C7 conical tank and an advanced nosecone on top. No fins. No fairings. All stages are absolutely level thanks to Editor Extensions, which means we don't need any launch clamps. MechJeb allows for precise TWR and Delta V information. Just one 1.25m reaction wheel. (I haven't covered command and control yet, but I'll give you a sneak peak - fewer reaction wheels are better.) The lone docking port is a standard 1.25m clamp-o-tron under the advanced nosecone at the top of the rocket, where it creates no drag. (We'll get to docking and docking ports too.) Final stage used for circularization has a TWR less than 1. This design got 2.08 large white tanks worth of fuel to a 90 km orbit, plus the hardware to allow it to function as a fuel depot, for less than 200K. Welcome to Cheap and Cheerful.

6. Aerodynamics Aerodynamics is one of the areas where Cheap and Cheerful can depart a bit further from standard design. When discussing aerodynamics, I'm specifically talking about nosecones, fairings, fins, and conical rocket parts. From a C&C perspective, aerodynamic features can add significant cost and weight, and must be considered not only on their merits, but holistically as part of the entire rocket system. RoT 6.1 - Put your best nosecone on the center stack. Just as it's a good idea to run your LFO engines as long as possible to extract maximum value from them, it's also a good idea to put your best aerodynamic nosecone on the center stack, where it will be used for the longest. Depending on how long a radial stage is burning, it may make sense to have the same nosecone as the center stack. It's generally worthwhile to put an advanced nosecone on a Kickback, and a basic nosecone on a BACC. Hammers may or may not be worthy of a nosecone. Fleas are... well, I'll just repeat my earlier statement that Fleas are useless, IMHO. RoT 6.2 - Rarely use fairings; but if you do, don't skimp. Fairings are fairly (ba-dum) expensive in KSP, and should generally be avoided. If you have just a few things attached radially on your payload (science experiments, small solar panels) then a fairing isn't justified. When you start having larger items (Gigantor solar panels, docking ports, landing legs) on the side of your payload, it may be time for a fairing. This is especially true if you're also having problems with the rocket flipping. Once you do decide to use a fairing, go ahead and cover everything you reasonably can, and make it fairly pointy - the vast majority of the cost is in the fairing base, not the fairing itself. Rot 6.3 - Rarely use fins. If you do need them, try the cheapest ones first. Many rockets need no fins whatsoever. If you have a reasonably aerodynamic front end of the rocket, and some workable level of control authority (gimbaling engine or substantial reaction wheels) then there shouldn't be any need for fins. If you do have trouble with your rocket flipping over, despite using a proper flight profile (staying close to the prograde marker), then try adding four of the smallest fixed fins to the very bottom of the rocket. Only if that doesn't work should you go for the larger and more expensive fins. Keep in mind that the cost of fins (particularly controllable fins) can quickly add up, and should be weighed against the cost of other solutions. RoT 6.4 - Fins should generally be used in groups of four. If you use three, place the first fin on the E or W side of the rocket. If you do need fins, the best arrangement is to use them in groups of four, mounted on the cardinal directions of the rocket (N-S-E-W). Not only does it track straighter, but the computer seems to be able to predict what the craft will do better. If you do decide to go down to three fins, place the first fin (the one you're controlling with the mouse) on the E or W side of the rocket. If you place it on the N or S side, then things will get a little weird when you start your gravity turn. Also note that you can vary the amount of authority the fins have by altering the height they're mounted on the rocket. If you're finding it too hard to turn with fixed fins, move them up higher on the rocket. RoT 6.5 - Use the C7 conical tank as much as you can. The C7 conical tank, which smoothly transitions your rocket from 1.25m to 2.5m, has the same fuel capacity and cost as an FLT-800 or a Rockomax-8. Compared to the Rockomax adapter for the same diameters, which costs 500 funds and doesn't contribute anything to the rocket's power, it's a no brainer. Unless you're using a mod that has 2.5m SRBs, all of your 2.5m radial stacks should have a C7 conical tank and a 1.25m nosecone on top. In my testing, the combination of the C7 tank plus an advanced nose cone was the best performer for 2.5m stacks. RoT 6.6 - Look at aerodynamics as part of a larger system. Not every aerodynamic problem is worthy of attention, and some solutions don't involve aerodynamic parts. Because the cost of aerodynamic parts is relatively high for something that produces no thrust, you have to consider what makes the most sense. For example, an advanced nosecone costs 320 funds, while a Hammer costs 400. In some situations, it may make more sense to surface attach Hammers and power through the aerodynamic losses instead of trying to minimize them with a nosecone. You may be able to live with suboptimal aero on your ejected stages, particularly if they're being ejected before you go supersonic. If you have an ascent that is too vertical because you don't have any fins and are relying on reaction wheels for an SRB-only first stage, you have to weigh the cost of the fins against the cost of increasing the fuel in a subsequent stage to compensate for the steering and aero losses. RoT 6.7 - Look at Fuel Tanks Plus for aerodynamic fuel tanks, including nosecones. I know I already plugged it once, but I would be remiss in not mentioning the aero components of Fuel Tanks Plus. The mod includes fueled nosecones in every diameter, and conical tanks in every diameter. Check it out.

5. LFO Tanks It's impossible to run an LFO engine without LFO tanks. The rules for tanks are few and straightforward. RoT 5.1 - Use fewer, larger tanks wherever possible. Using fewer tanks keeps the part count down, and the larger tanks are slightly less expensive per unit of fuel. The old mass penalty that the white tanks had no longer exists, so there's no reason to avoid using them. RoT 5.2 - Put enough tanks in each stage to run the engines for a long time. As previously mentioned in RoT 3.3, you should run your LFO engines for as long as you reasonably can to extract the most value from your investment, generally at least two minutes per engine. This translates to a minimum of 2 white tanks for a Mammoth, 1 white tank for a Rhino, 2 orange tanks for a Mainsail, 3/4 of an orange tank for a Skipper, 1/4 of an orange tank for a Poodle, two FLT-800s for a Swivel or Reliant, and an FLT-400 for a Terrier. Once you're in space and no longer have to maintain a higher minimum TWR, the tankage per engine can increase. I've made plenty of rockets that have 3/4 of an orange tank attached to a Poodle as a transfer stage. RoT 5.3 - Fuel Tanks Plus gives you a lot more options. One of my favorite mods is Fuel Tanks Plus by Necrobones. It's a stockalike mod (actually slightly better than stock, IMHO) that gives you additional lengths in each tank diameter. For example, the 2.5m tanks include the Rockomax 48, 96, and 128, representing 3/4 of an orange tank, 1 1/2 orange tanks, and 2 orange tanks of LFO capacity. Each tank also has multiple setups (such as holding just LF to power an LV-N) and multiple skins to allow a customized rocket appearance. Using this mod will allow a reduced part count and improved appearance for all your LFO rockets. Be sure to check out the video which demonstrates the 1.0 version of the mod in the thread's OP.

4. Electrical Most craft need electrical power, whether it's for transmitting science results, running a science lab, scanning a planet, powering reaction wheels, or just keeping a probe core running. Here are the Cheap and Cheerful Rules of Thumb for electricity on a craft. RoT 4.1 - Use solar panels as much as you can. Perhaps this is obvious to many, but solar panels give you the best bang for the buck when it comes to power, as long as they're receiving enough light from Kerbol to function. Fuel cells are heavier, more expensive, and slowly use up your craft's fuel supply. RTGs are horrendously expensive, heavier, and not available until the end of the tech tree. Stick with solar panels as far out as Dres, and possibly Jool for craft with lower power requirements. RoT 4.2 - Stick with Z-100 and Z-1K batteries. While capacity of a battery scales linearly with weight, it does not scale linearly with cost. Z-100s and Z-1Ks are your best bargain. Stick with them for most craft unless you're using a lot of power while on the dark side of a planetary body (like a science lab) or need the 2.5m form factor and lower part count of the Z-4K. RoT 4.3 - For early craft only going to LKO, put fixed panels on the E and W sides of your craft. Putting panels on the E and W sides of the craft as it sits on the pad will ensure that one panel or the other will point at the sun as long as the craft doesn't rotate around its long axis. The opposite rule applies for deployable panels, which should be placed on the N and S sides of the craft, Kerbal ladder access permitting. RoT 4.4 - For complete coverage with fixed panels, mimic the faces of a die. In order to get complete coverage with fixed panels, the most efficient method is to mimic the arrangement of faces on a platonic solid, such as dice with 8 or fewer faces, i.e. a D4, D6, or D8. That way, no matter which way the craft is pointed, at least one or more panels will always be generating power. BTW, the angles in between faces are approximately 70 degrees, 90 degrees, and 110 degrees for each of these configurations. RoT 4.5 - Default to placing 3 deployable panels on the widest part of the payload. If in doubt, put deployable panels using 3x symmetry on the widest part of the payload. (Panels on narrow parts of the craft are more likely to be blocked by other parts of the craft.) If the craft is a satellite or deep space vessel that will never enter an atmosphere, use the unshielded versions. If you're going to enter an atmosphere, use the shielded versions. This configuration will always generate power no matter the orientation of the craft. Album with examples

There's more than a little overlap between BDB and C&C. It's a case of synchronicity in this instance, because I started building this way long before I had ever heard of BDB. :-) Next entry should be tonight or tomorrow.

3. LFO Engines Liquid Fuel and Oxidizer engines (LFO for short) have a crucial role in C&C design, although they may be used slightly differently than in more traditional applications. RoT 3.1 - Almost always use gimbaling LFO engines. One of the major strengths of LFO engines compared to stock SRBs is their ability to gimbal, i.e. steer the rocket using off-axis thrust. Gimbaling engines provide strong positive control authority in both atmosphere and vacuum. The exceptions to this rule are for very small engines (such as the Ant) where the probe core or capsule provides enough attitude control, and the LVT-30 in the early game when you don't have anything better. Once you have gimbaling engines unlocked, they should be just about the only LFO engines you use. RoT 3.2 - Match tank and engine diameters for lifters. Whenever you change diameters in a rocket stack, you end up using extra parts (adapters, fairings) which drive up the price, along with additional aerodynamic considerations. In general, keep all your tanks and lifters the same diameter (i.e., 1.25m engines under 1.25m tanks, 2.5m engines under 2.5m tanks, etc.) for each stack. Minimizing the extra "bits and bobs" which add cost and weight is a key part of C&C design. Once you're out of the atmosphere, this rule is much less important. RoT 3.3 - Run your LFO engines for at least two minutes in your lifters. LFO engines are more expensive than SRBs for the same thrust. To maximize the return on your engine investment, it's important to fire those LFO engines for as long as you reasonably can. The RoT is to put enough fuel tanks on top of each engine so that it will run for at least two minutes, possibly longer. If this reduces your TWR to a level which is too low, then it's time to bring in the SRBs. Also note that this RoT can be averaged in the case of asparagus lifters (which are not the first choice for C&C design, BTW) where the center stack ends up firing for a very long time. RoT 3.4 - LFO transfer stages should have a TWR between 0.3 and 1. If your TWR is too low, you're going to have trouble making an accurate transfer in a single burn and will start incurring major steering losses. If your TWR is too high, then you either brought too much engine (and made your rocket too expensive) or aren't pushing enough fuel for the thrust you have (and aren't maximizing the return on your LFO engine). RoT 3.5 - Most LFO landers should have an initial TWR between 2 and 5 for the body that they're landing on. It's always exciting when landing on the Mun or Minmus for the first time. Those new to the game or not well versed in design will frequently overbuild their landers, hauling around way more engine mass than they need. Slapping a Terrier on the bottom of a Rockomax 16 works great as the power section for a Mun lander, while a Minmus lander can get away with just a Spark under a Rockomax 8. Keep those initial TWRs low. RoT 3.6 - For serial staged LFO rockets, the upper stage should have thrust between 1/3 and 1/6 of the lower stage. In order to get maximum return from your first stage LFO engine, you need to stack a lot of fuel on it - at least two orange tanks for a Mainsail, and at least 3/4 of an orange tank for a Skipper. When you do stage, the next engine should be substantially less powerful. In addition, the need for higher thrust levels goes down towards the end of a burn to LKO. So long as the first part of the launch has a healthy TWR, the last 500 to 700 m/s to reach orbit can be at a TWR which is significantly below 1. The lowest I've gone is 0.42, but 0.5 or 0.6 should be workable in most situations. This can actually be a bit of a problem with 3.75 meter rockets, since one engine is half the thrust of the other. RoT 3.7 - 2.5m engines are in the sweet spot. Many C&C lifters will use 2.5m LFO engines, since they tend to occupy the happy middle ground between cost, performance, and tech requirements. There is nothing wrong with a rocket which uses only Mainsails, Skippers, and Poodles. They can also be augmented with a small number of SRBs, (such as two Kickbacks with a Skipper) which keeps the decoupler and nose cone costs down.

Highguard, Thanks for the feedback. The plan is to do a few more posts covering major systems (aero, command and control, LFO engines and tanks, electrical, and rocket geometry) then add some imgur albums with annotated photos illustrating various concepts and how it all fits together. Part of the reason for doing this is that my actual KSP time is limited due to RL travel. I figured that jotting down "lessons from the trenches" was something useful I could do without having KSP actually in front of me. Regarding beginners, I don't really see them as the target audience. I should probably make that clearer in the OP. If I start explaining every acronym, then I start stomping on the toes of folks like Pecan who have created some very good newbie-friendly material.

OhioBob, I agree with Slashy 100%. These tables rock.