V1rtua1An0ma1y

I think it was just 225kn, then. Either way, the video I saw specifically said 19.1 and was posted just a few weeks ago: . I do find it odd that in the video the ramjets begin to overheat at the time I would be losing thrust, so I wonder if there's modding involved...

I've seen videos of ramjets getting up to 250kn of thrust around 25km and these crafts are able to go over 2km/s in the atmosphere. Every time I try this, the engines peak around 210kn and then start losing thrust. I'm stacked with intakes and the intakeair resource is even above .50 when this starts happening. Can anyone explain the finer points of ramjets?

*Disclaimer* This is not the end-all of how to SSTO and I'm a very patient person. This may not work for you, but here are a couple points that I think would've made my life easier in designing a true SSTO from the get-go: 0.) This shouldn't need to be said, but if you've ever built anything in KSP, use struts liberally. Everything wobbles, and your plane will veer off the runway unexpectedly if things are flopping around. 1.) (And this has been said already) The bigger it is, the more difficult it'll be to get in to orbit. I'd aim for something like 20tons and wouldn't exceed 40 if you're new to the SSTO scene. 2.) Intake Air. I know it's been said a few times about 2:1 intakes to engine, but I've found that something like 3 or 4:1 works well for me. That means more altitude and more speed before you start in on your precious rocket fuel. 3.) Lift. If your 40-ton space plane has just 1 set of the delta wings, you might find it tough to get off the runway. Give it a decent wingspan, and place your center of lift behind your center of mass. Just remember that the farther back that lift is, the harder it'll be to get the nose up and climb effectively. (I like putting canards far forward to at least coax the nose up off the runway). Also, have your rear landing gears slightly higher up (shorter) than the front. This causes the plane to sit on the ground pointing upwards a bit already. 4.) Efficient rocket engines. Your thrust to weight doesn't have to be much over 1. You're going to have burned your jet fuel, you'll be in less-dense air, and gravity will have diminished somewhat. A thrust to weight of 1.5 or 2 just isn't necessary. As long as you can manage a greater than 1 ratio, go for efficiency over power every time. 5.) Precision. This has to do with how you ascend. - The faster you're going in the atmosphere, the more you'll be paying for it via drag. If your horizontal speed is 400m/s and you're only 5km off the ground, you're doing it wrong. You could have used a lot of that energy to climb instead. - Know how much fuel you have. If you brought 2 Mk1 fuselages, then you have 300 liquid fuel to use on the jet engines. If you're in orbit and carrying 100 of that around, you did it wrong. You can't use it via rockets since you won't have enough oxidizer. - Push your turbo-jets to the limit. Watch your resource tab and specifically your intake air. You'll probably want 2 jet engines, and they'll function until your intake air hits about .10 . The higher you can go before you turn on the rockets, the less fuel you'll need to get to orbit. If you're climbing slowly, your plane will start to pull to one side as one of the engines suffocates. If you can catch this as soon as it starts, this is exactly when to kill the jets and fire the rockets. 6.) Your SSTO is not a rocket. I can't stress this enough: It's a plane. If you're taking off vertically or not equipping jet engines, or staging a bunch of parts during your ascent, then you've built a weird rocket, not a plane. A standard ascent for me - Take off and climb as quickly as you can with only jet power. Once you're above around 10km or more, start to level out and gather speed. The higher you go, the less the air is going to fight you. Your goal should be to get to 600m/s when you're at about 18km (this doesn't have to be exact). Watch your intake air and continue climbing slowly. Ideally you'll run out of liquid fuel for your jets at the same time you run out of intake air. At this point you want to light the rocket and shutdown the jets (use an action group so you can close all of your intakes as well -> less drag). You're still a plane. If you start to climb at an angle higher than 60, you're wasting energy to gravity losses; not to mention you need substantial horizontal speed to orbit anyway. Climb at around 45 degrees, get your Ap above 70km, and circularize accordingly. *Using these rules I can put a plane into a circular orbit at 80km with almost 2000 delta-v remaining. That's more than enough to dock with any station or satellite, assuming similar orbital planes. Anyway, I'm no expert, I've just found something that works for me. Please ask questions or provide better means of doing this if you've got them!