GoSlash27

"Ratio", not "fraction". That is to say, the mass of the payload exceeds the mass of the launch vehicle itself. As an SSTO, no less! A turbojet mass lifter is capable of lifting an exact duplicate of *itself* into orbit. Best, -Slashy - - - Updated - - - UA, As a user of FAR, you've seen first hand that SSTO spaceplanes don't actually require ludicrous engines to work once the aerodynamics are fixed. FAR nerf-clubbed the jets like baby harp seals, and rightfully so. They now work very well as jet engines and make lousy rockets, but SSTOs still work despite all that. Wanderfound even has interplanetary SSTOs in FAR. Best, -Slashy

Enjoyed the book, though there were a couple plot points that irked me. I hadn't thought about KerbMav's spoiler, but yeah... not very realistic. His Kerbal-esque water generation trick also struck me as profoundly ill-advised. Not just for the reason shown in the book, but because of the chemicals involved and the fact that he was in a closed atmosphere. I expect to hear some very bad disco in the movie Best, -Slashy

A spaceplane should be "allowed" to do anything the player can make it do. The issue isn't with spaceplanes, it's with the engines, particularly the turbojet. They're simply too powerful, efficient, and cheap for any rocket to compete with, even in the heavy lift role. They are capable of achieving payload ratios over 100% and orbiting them at $30 per tonne. With the aero rework coming down, there's no reason why spaceplanes shouldn't work with severely nerfed air breathing engines. The engines themselves just shouldn't be better rockets than actual rockets. Best, -Slashy

I don't recall anybody complaining about realistic parts making the game easier. I also haven't gotten the impression that people just want to make the game more difficult. The idea is balance, not difficulty. There are some parts that are so bad they never get used. There are other parts that are so powerful that nothing else ever gets used. There's no fun to be had in all these shiny rocket parts if you only use a few of them. Best, -Slashy

Not true. I don't intake-spam and run 1.0 wing lift coefficient per tonne of aircraft. The turbojet is still so buffed that it obviates all other engines. There's simply no call for a turbojet that achieves orbital velocity. It breaks the game and it's totally unrealistic. Best, -Slashy

When setting up an interplanetary burn with long burn times, I'll park in a highly eccentric orbit while waiting for the window. This gives me a much shorter burn during the actual transfer while keeping the Oberth effect in play. Although I've never had to perform a 60 minute burn... Best, -Slashy

^ What they said. If you start your turn early (I generally begin around 6km), you can keep your nose pointed prograde throughout the ascent. Not only does this save DV by rounding off the corners (as shown above), but it also increases efficiency by keeping your thrust aligned with your velocity vector. Finally, you want to perfectly balance your gravity losses with your drag losses. This profile does a good job of that. Best, -Slashy

Pecan, 23* is the maximum lift/ drag possible for KSP wings. If it is necessary to hit 23* to continue the climb at around 30 km up, then you're at the smallest wing area possible for a successful spaceplane. Any less AoA than that and you're carrying more wing mass than you need, which costs DV. Any more than that, and you're probably not going to space today My wings pretty much crap out at 32 km, and it sits there for a while building speed until the centrifugal force is sufficient to get me climbing again. This is generally good to get me between 65-80 km pe before I finally have to kick in the rocket. Best, -Slashy

ShadowZone, It depends. It sounds like a lack of pitch authority as you approach terminal velocity. This is usually due to a drag misalignment more often than static imbalance in my experience. Make sure your intakes are as far back as possible and add control surfaces (elevators *and* canards) in a balanced fashion to give you more pitch authority. Also, you shouldn't be anywhere near terminal velocity at 12 km. You want to be climbing ballistically to get out of the soup. You don't want to approach Vt until you're at 25 km or so. Best, -Slashy *edit* If you've been using high- mounted wings, that'd do it. Wings exhibit less drag than other parts at low angles of attack and high speed. This can create a pitch moment that pushes your nose down.

Let's look at a hypothetical trip to Eeloo. Nice and far, and Mun sized target. Using a dedicated launcher and assuming a 1 tonne payload, the ant produces a package totaling 1.32 tonnes. Landing that 1.32 tonnes will create a vehicle that weighs 1.77 tonnes. So your LV-N would need to cart 1.77 tonnes to Eeloo and 1.1 tonnes home. Getting home from Eeloo is 2700 m/sec and getting there is 3,700 (worst case). Splitting the difference on the payload yields a mission package of 9.9 tonnes. If you use the LV-N to execute the entire mission, than it's a 1 tonne payload for 7,650 m/sec is a 10.8 tonne package. Leaving 3 tonnes of fuel in orbit won't save you a tonne of fuel over the landing and launch at Eeloo, so it works out cheaper to have a daughter lander. This loss is compounded as you visit more planets in a single trip, and of course the demand on launch vehicles increases linearly with mass. Best, -Slashy

Laie, The difference is a lot more than it would appear. Using the recommended intake area, a turbojet will flame out at 32km altitude while going 1.2km/sec, but is capable of exceeding 2.2 km/sec (essentially orbital velocity when you throw in rotation) at the same altitude if you build speed. More speed means more air, which means more thrust and thus more speed... That's a 1 km/sec DV difference that must be made up in a very short time if you elect to not hang around at 32km altitude building speed which requires a whole lot more fuel and much more powerful rockets to complete the burn. Turbojet and RAPIER spaceplanes work best if not flown like rockets, which is why the profile is so important. Best, -Slashy

It's kinda confusing, but I mean what Marvin said. Since the flight has an apoapsis the entire time, I am differentiating by referring to the current apoapsis as what will become the final periapsis upon circularization. If you have enough velocity, you will drift right up to orbital altitude with hardly any drag and have almost all of your orbital velocity when you get there. You can generate a whole lot of velocity from turbojets without very much intake area, it's just a matter of patience. And of course, achieving orbit is all about velocity, not altitude. tl;dr Establishing orbit in a turbojet spaceplane requires a lot less rocket thrust and a lot less intake area than many people assume. Best, -Slashy

This would be drifting off- topic, but I'm sure if you tried designing a mission using each mode and comparing the size and cost you'd see why. If you're interested in exploring this subject further, I'd be happy to join you in a dedicated thread. Best, -Slashy

The short version is we don't. Life is essentially a chemical process, and can exist in all sorts of weird circumstances. The thing is, if it's sufficiently chemically different we may not be able to recognize it as "life" Therefore we seek circumstances we are familiar with so we'll recognize life when we see it. Best, -Slashy

^ This. People use them in landers, but if they did the math they would find that nukes aren't the best option for the job. They are ideal for interplanetary travel and they should be. I would like to see them require specialized heavy and expensive fuel tanks though; ones that cannot be filled using kethane. Best, -Slashy

And their high mass, poor thrust, and huge price tag. I have no problem with the nuke remaining as-is. It's ideal for the job of interplanetary travel, and it should be. Best, -Slashy

Aye, but the important thing in a game like this is balance. You need a reason to use all the different engines in the game. If you're going to have something that's clearly superior across the board, it should be either more expensive or unlocked later in the tech tree. Ideally, there should be no engine that's superior across the board. Best, -Slashy

#1 culprit is the turbojet. An engine that good is completely ridiculous and breaks the game to the point that it makes no sense to use anything else. It's so good, in fact, that no real life analogue exists for it. I'd just as soon remove it from the game completely. A basic jet is a fairly good representation of an actual high performance jet engine. #2 would be the Rapier. If I didn't have access to the turbojet, I'd use Rapiers for everything. Reducing the thrust to about 50kN should do it. #3 the 48-7S. It's too cheap, too efficient, and too powerful. It renders almost every other rocket useless. It's supposed to be getting a vicious beating with a nerf bat, so that's a plus. Best, -Slashy

Not true. This can be done with as little as .018 m^2/engine, which is about half of what most people use for intakes. It's just a matter of being patient around 30km and letting the speed build. Observe: http://s52.photobucket.com/user/GoSlash27/slideshow/KSP/intake%20tests Any of these intake combos are sufficient to achieve orbital periapsis: Intakes per engine 3x XM-G50 2x circular intake 1x circular intake + 2x XM-G50 1x Ram intake + 1x XM-G50 1x Shock cone + 1x XM-G50 Once you've established the periapsis, it takes very little thrust and DV to circularize. Best, -Slashy

Shadowzone, You've got a lot more spaceplane there than you need for that job. The single engine design I outline here is capable of putting 6 kerbals and 3.5 tonnes of payload into orbit. I notice you've got a whole lot of wings on that thing for being 35 tonnes. You've also got what appears to be insufficient intake area for your engines. Finally, you've got more engines than you need. Remember that moar engines doesn't add anything but weight and drag when starvation sets in. My guess is your drag is overpowering your thrust and killing your acceleration while you're still below 32km altitude. This leaves you with insufficient speed to establish periapsis and your nuke unable to make up the difference in such a short time frame. Follow Pecan's lead on the launch profile. Best, -Slashy

^ I'll second that, though I use more jet fuel and less rocket. I also don't use nearly that much intake area. The key to a successful spaceplane is climbing through the 25-32km altitude region with a pitch of 23* at terminal velocity. If you can't climb and you're at or above terminal velocity, add wings. If you can't climb and you're below terminal velocity, add engines or lose weight. If you can't climb and you've had to reduce throttle to keep the engines lit, add intake area. I use 1.0 Cl per tonne for wings, 1 turbojet per 15 tonnes, and .018 m^2 intake area per turbojet. Best, -Slashy

Holding "shift" while rolling the part will make it rotate in 5* increments, allowing you to attach your gear closer to the bottom of the fuselage while still being aligned properly. Best, -Slashy

RCS is the system that translates and points the craft through the timed firing of thrusters. Monopropellant is the reaction mass that is ejected by most RCS systems. Vernor engines would count as RCS subsystems because they are actuated and controlled by the RCS system. Mono engines (O-10) would not be considered RCS, since they are operated through the primary flight controls. Best, -Slashy

Using Vanamonde's analogy, it was originally intended to be an 18 wheeler, but budget constraints turned it into an oversized panel van and the loss of it's primary mission forced it to adapt to being the world's least- efficient commuter car. The failure had nothing to do with it being a first attempt. The failure was due to budgetary reductions, curtailed missions, and the compromise between building and operating costs. The concept itself is still sound (even more today than ever), but it has to be executed. Nice things about the shuttle: It was highly reliable, combined payload carrying capability and habitability, Put a huge tonnage of payload into orbit, did all sorts of jobs nobody had even guessed would be needed, and inspired generations of astronauts, scientists, and engineers. It's an iconic, beautiful machine. Best, -Slashy

Unfortunately, I won't be able to participate in this for a while. My neck and shoulder are fubar'd again. I can, however, enjoy watching people raising the bar on this challenge, so AFAIC "mi rocket es su rocket". FWIW, I have run a ridiculously tiny payload SSTO that was able to manage under $450 per tonne using the 48-7S. Might be worth playing around with... Release the hounds! -Slashy