tsotha

This is why people used to discuss things like engine efficiency and dV in terms of exhaust gas velocity instead of Isp.

The same thing happens with jet engines, which you have to test before you get air intakes. You just have to stage it. It doesn't have to work. Note this is true with regular LF engines as well - you set up your engine under test such that there's no way for fuel to get to it and the test will complete just fine when it's staged.

Mathematically, the lower it is the less fuel you're going to be using in the long run. As others have pointed out, though, at 70km Kerbin you're always going to be doing your rendezvous from ahead of your fueling station, since you can't be in a lower orbit. Ultimately it depends on how tight your dV budget is. If you don't need that last ounce of fuel putting it at 100km or so will save you a lot of aggravation.

The problem with using lights is you won't see anything until you're 400m from the surface. That's probably fine if you thought you were at, say, 1000m. But if you're coming down on a plateau at 4500m you're probably going too fast to benefit from a 400m warning unless you have a huge TWA or you're being particularly profligate with fuel. Before I started using KER I would check radar altimeter in IVA until the meter started moving (3000m). That would give me a ballpark for the altitude of the surface so I wasn't going too fast when the lights came into play.

You can't judge an engine purely on ISP. The 48-7S is ridiculously light, so if you're building something small it's the only way to go. And as others have pointed out, atmospheric ISP doesn't matter that much except on the first stage of an Eve return rocket. The aerospike isn't entirely useless, but it's mostly useless given its paltry thrust.

Right off the bat those x4s are horribly overpriced. I never use them for Kerbin launches unless I've got a test contract.

A multiplier can be less than one. But we could call it a divider instead, if that's more obvious.

Perhaps, but since I'm not going to read 62 pages looking for it, maybe you can be more specific.

Hmmm, well, that's what's great about landing on Minmus. Sometimes I don't even make a "lander" - I just put a couple SAS modules on my rocket and lay it down wherever I happen to end up. When it's time to leave I use the torque to lever the thing straight up and fire the engines. The others are right, though. Wide landers with a low center of gravity are the way to go. Make sure you kill all your horizontal velocity, and the steeper the slope the slower you need to touch down. SAS helps too, since it means you can put all the weight on the up-slope legs and gently lower the others. For a basic Mun lander, instead of having one tall tank I'll split my fuel into four tanks and attach three radially from the center. The legs go on the outside, so the thing ends up looking more like a spider than a tower. Also, you don't need to attach the legs flush against your ship - if you have the clearance you should angle them outward to increase your footprint even further.

Thrust multiplier?

I never have trouble with money on hard mode (60% funds) and no reverts. I accept and complete every contract. This is my advice (which would change if you're going much below 60%): 1. Try to do multiple contracts in each launch, but don't try to do too many "flying over Kerbin" contracts at once. Two or three is probably the most you should do at once. 2. Use SRBs as much as possible, but don't overdo it. You need a bit of experience to know just what value to set the thrust limiter on an RT-10 such that you're going between 80 and 120 m/s at 4500 meters for a rocket of a given mass, and it won't save you any money if you have to launch four times to get it right. If you have a multi-stage rocket use SRBs for the bottom stage, since you're not going to be able to recover them. One strategy is to put SRBs on radial decouplers around a T-45. Adjust the thrust limiter on the SRBs such that you'll be operating the T-45 at 25% or so. This way you can still steer your rocket but you get the benefit of cheap dV from the SRBs. 3. Remember for "flying over Kerbin" contracts if you don't satisfy the contract on the way up because conditions weren't right, you may be able to get a second bite at the apple on the way back down, particularly if you still have fuel. 4. You can do pretty much any number of "in orbit" contracts in one launch. Just put yourself in a nice elliptical orbit that covers all the necessary altitudes and complete them one at a time. I usually wait until I have four or five of these before I complete them all in one shot. 5. You can use the device under test before you test it - engines that get started by a control group or right click menu don't count as being staged. Also, if you stage an engine you can add empty stages beneath it and re-stage it (even if it's running at the time) to complete the contract. So if you get a test contract for something heavy like a KR-2L, build your rocket around that engine instead of treating it as cargo. 6. An engine doesn't have to work for you to test it. You can take all the fuel out of an SRB and still complete the contract. You can stage a liquid or ion engine with no fuel of the correct type to complete a contract. You can stage a jet with no air intake and no liquid fuel to complete a contract. So, for example, if you get two "landed at Kerbin" contracts, one for an RT-10 and one for a basic jet engine, make a "rocket" consisting of a capsule with the RT-10 on the bottom and and upside-down jet engine on the top. Take all the fuel out of the RT-10. Take them out to the pad and stage them both - contracts complete. Your rocket won't budge and you'll get full salvage value for all three parts. 7. Speaking of "landed at Kerbin" contracts, don't bother adding them to rockets that will actually fly. It just adds extra weight, and if you aren't landed at the pad or runway at the end of the flight you won't get full salvage value. Do all "landed at Kerbin" contracts on stationary "rockets". These contracts are free money. 8. Stack decouplers only decouple the side the arrow is pointing to. Let's say you have a test contract for a rockomax decoupler. If you put it on top of a capsule with the arrow pointing up (which is the default) it will stay attached when you stage it, so you'll get to salvage it if you recover your rocket. 9. The contracts most likely to lose money are the ones that require you to exceed terminal velocity lower in the atmosphere, e.g. testing something at 4500 meters going at least 400 m/sec. They don't pay well, usually require more than one engine, burn lots of extra fuel, don't have much margin for error, and conditions are such that you'll be unlikely to satisfy other contracts on the same launch. If you're going to decline contracts, decline these. Your very first launch should complete all four of the initial contracts. Just make a basic rocket with an engine, twelve fuel tanks, a capsule, and a parachute. That's enough to get you into orbit and back. You should have enough fuel to assist your parachute in a soft ocean landing, and if you "recover" the craft before it tips over you'll be able to salvage all the parts. I think that leaves you with something like 120k at the 60% setting.

Which is fine. If they model jet engines accurately then there's no space planes. Just like IRL.

If it stops working altogether you may have run out of power.

I can't tell by looking at it - what kind of engine is that? All I have so far is the basic jet.

Do control surfaces have less influence at lower speeds? Seems like that's the way it should work to me, but I don't know if it's true IRL and even if so whether it's true in KSP.

So I installed Fine Print to give myself some more variety in contracts, and all is going well, generally. One thing I don't understand is how to do those "fly over such and such place on Kerbin". I made a plane with a basic jet engine and headed out. It took hours. And not interesting hours, either, more like "are we there yet?" hours. I'm kind of curious how other people are fulfilling these contracts - are you waiting until you have turbojets and doing fast, high atmosphere jaunts to the target area? Are you using rockets to take your plane sub-orbital to the area of interest and then flying to the targets? Are you somehow using a rockets for the whole thing instead of a plane?

I had a design exhibit this exact behavior. Ultimately the problem was fuel-related CoM changes that made the plane so back-heavy that slowing down would cause the nose to pitch up (and in my case, stay up). At launch it was barely flying. At landing... well, everything can land once.

Rumor is landing wheels are no longer massless as of 0.25. I have not checked the settings myself, though.

Isn't this just because you've added some weight to your rocket and crossed whatever threshold destroys the pad?

Yeah, just turn off destructable buildings. It's something that sort of seemed like an okay idea but turns out to be just annoying because the runway and launchpad are too easy to destroy. Supposedly they're adding upgradable buildings in a future release, and if that means you can upgrade the runway and launchpad to handle larger ships I may turn it back on at that point.

And with all that you can still get 10,000+ science in one launch.

IMO the key to docking starts in the VAB. Most people new to docking don't understand what's important from the ship standpoint, so they've already made things difficult before they even get off the pad. Make sure: 1. Your ship is small. Practice with something under ten tons. It's tempting to try to jump right to orange tanks. Don't. 2. Both the docking ship and the target have active SAS. It's really difficult to dock with something that's rotating. You can do it, but that's really part of the advanced class. 3. You have 4 RCS thruster blocks arrayed symmetrically around your ship's CoM. The idea is you want to point your ship in the right direction and then translate to where you need to be without changing your ship's heading. If you don't have enough thruster blocks or you didn't put them in the right place your ship's heading will change as you try to translate, which makes everything much harder than it needs to be. Make sure your CoM doesn't change as your fuel stores are depleted, or failing that make sure the thruster blocks are positioned around the CoM the ship will have when you're ready to dock (hope the rest of the flight went as you planned). 4. Your ship is "tight". When you translate the nav ball shouldn't sway back and forth as you rotate or translate. This means lots of struts and a preference for short, squat ships over long skinny ones. Avoid attaching parts with docking ports as that creates a flexible joint that will cause your stack to bend. If it's necessary use girders and struts to keep the joint from flexing. You should be able to take your ship to the pad, turn off the gravity, and translate back and forth without your heading changing at all. Ideally you can do this both with 100% fuel and also when your tanks are bone dry. If your course sways back and forth before settling out, figure out what's flexing and shore it up. If your heading changes either you put the thruster blocks in the wrong place or your CoM is moving as you use up your fuel. The latter case may require substantial rethinking of your design Once you have lots of experience you can dock with (slowly) rotating objects and dock ships that sway back and forth as you try to move them. But you'll never get there if you can't get the basics down.

This is why I turned building damage off. I'm considering that myself. I don't mind buildings blowing up when you hit them, because you're not, you know, supposed to hit them. But landing on the runway at 5 m/s shouldn't damage it. It all seems rather arbitrary, and I don't see what it adds to the game.

If you're going through an SOI change at high time compression this will happen. It has something to do with the way the engine does fewer calculations per distance traveled. When you get near the transition, cut your time compression to 1x.

I didn't even think to try it. "Why would I add struts? That will keep it from separating."