Wanderfound

Kerbodyne Muttonbird. Interplanetary to go. Craft file at https://www.dropbox.com/s/lc3abgswoipa73u/Kerbodyne%20Muttonbird.craft?dl=0

"Too Fast, Too Furious"? Sheesh. Trek continues to slide down the garbage chute. It was one of the few SF shows that was actually SF instead of fantasy-in-techno-disguise (AKA Star Wars). It wasn't always good SF, but at least it was SF. Now it's just another idiotic action movie franchise.

Yup. The point I was getting at wasn't about reducing your takeoff run per se; it was about reducing post-takeoff (and especially post-atmospheric) mass in order to maximise fuel efficiency. Reducing the number of engines will reduce your runway top speed, but it should also reduce the speed required for takeoff (by reducing wing loading). So even a seemingly large reduction of thrust often does not have as much of a negative effect on takeoff ability as might be expected. There's nothing inherently wrong with having lots of jet thrust (look up the Kerbodyne Goblin sometime...), but I did want to make the point that it's often counterproductive, and is also much less necessary than it may appear. As with rockets, you can go with brute force and strap on moar boosters, or you can shave your payload down, streamline and try for efficiency. They're both valid approaches. But I do realise that I'm banging on about this a bit, so I'll try to leave it there. Answering in reverse order: Yes, although they tend to give meaningless numbers for the ÃŽâ€V of the air-breathing engines (and the TWR figure is a bit dodgy too, given how much jet thrust changes with speed and altitude). With a RAPIER/nuke ship, my normal pattern is to light the nukes and kick the RAPIERs over to rocket mode once the jets lose their enthusiasm, shut the RAPIERs down once the apoapsis hits 60,000m and do the rest on just the nuke. A particularly low TWR ship (e.g. a big Mk3 with only one nuke) may require a bit of extra RAPIER thrust during circularisation, but you still want to do as much as possible of the burn on the hyper-efficient LV-N. Nukes are unnecessary and counterproductive for LKO lifters, but if you're having to do 1,000m/s+ ÃŽâ€V transfer burns after you hit orbit the isp advantage pays off heavily. Maximum weight? No idea. But the single-engine ship shown in my earlier post is comfortably within the limits; notice how much runway it has to spare. If you want to push the limits and don't care about elegance, you can always just ski-jump off the end of the runway; so long as you start climbing before you crash into the ocean, you're all good. The top speed of an aircraft is the point at which thrust is balanced by drag; mass is irrelevant in that calculation, except for the fairly minor factor that more mass -> higher wing loading -> higher AoA -> slightly more drag. Higher jet TWR has relatively little effect on top speed; what you gain from extra engines is primarily acceleration rather than speed. Acceleration is fun, and you need enough to enable takeoff, but if you're going for range you want to be focussing on top speed rather than acceleration.

I normally set my control surface mass tweakables to be the same as the wing they're mounted on.

Heavy bits at the top, draggy bits at the bottom, gimbal is good. Do a proper gravity turn (i.e. not "climb to 10km, then wrench the nose to 45°") and keep the nose close to prograde. That's all there is to it, really. So, if you're flipping: tailfins. And gimbal. Strapping a quartet of Thuds to your core booster is an easy way to substantially boost your gimballing ability. You'll also gain a large benefit from onion or asparagus staging; run fuel lines from the radial boosters to the core, so that the core is still fully fuelled when you drop the boosters. Something like a Skipper/Thud core surrounded by onion-staged Mainsail LFBs should do the job fairly easily. But, yes, it's going to be a bit heavy; a 36 ton payload is not a small lift.

Assuming that there isn't a bug somewhere: screenshot? There might be something about the design that is causing unusual stress on the tail.

The reason I'm asking about takeoff is because it's the chokepoint on jet thrust; the minimum number of jets required is basically defined by "what do I need to hit takeoff speed before the end of the runway?". If you can get it off the runway and into the air, you can generally get it to orbit. So, minimising your takeoff speed may allow you to drop an engine or two, which will in turn reduce the dead weight you're pushing through space after you've reached orbit, increasing your range. My usual design when I'm trying for a maximum range ship is basically "one nuke, plus as much LF tankage as I can get into the air on two RAPIERs, with as little wing as possible and just enough oxidiser for the apoapsis boost". But there's a balance involved there, as there's an inverse relationship between thrust and lift required at takeoff: high TWR ships can get away with tiny wings, low TWR ships tend to need more lift.

I'm flying with FAR, so there will be some differences if you're in stock. You can see the profile and fuel remaining in the album above, but in general: 1) Climb to above 10,000m at a sufficiently steep pitch that you remain subsonic until you're out of the thickest bits of the atmosphere. 2) Level off to about a 10° pitch so as to crank up the speed to at least Mach 3 (and preferably 4+) by the time you hit 20,000m. 3) Keep it mostly level as you approach the jet ceiling (between 20 and 30km, depending on ship and piloting) in order to maximise your jet speed. 4) Light the rockets and gently lift the nose as soon as you maximise your jet speed. In all of this, keep an eye on temperatures. If you start to cook, climb more steeply. Kerbal Flight Data is very useful for this (and for other stuff, too; highly recommended for all spaceplaners). The profile will vary a bit based on the design. If you're well within your temperature limits, a shallower climb is usually worthwhile; if you hit the jet ceiling before you get up to speed, a Silbervogel style "climb and bounce" ascent (as shown above) can be helpful. That trick works better in FAR than stock, though; stock tends to apply excessive deceleration as you lift the nose during the "bounce". The stock ascent profile is fairly similar to FAR these days, but with a slightly lower jet ceiling and a greatly reduced ability to maintain speed while manoeuvring. Design-wise, FAR allows you to get away with a bit less in the way of engines, but tends to require a bit nore in the way of wings and tailfins. If you're just trying to get a heavy load to LKO, stick to jets and high TWR oxidising rockets (e.g. RAPIERs, or a Turbojet/Skipper combo etc). Nukes are best kept for interplanetary.

Bad stall or minor stall? A slight stall during takeoff (particularly on canards) is fairly normal. So long as your airframe design is stable, you can generally hold a minor stall for quite a while (e.g. long enough to gain sufficient altitude that you can afford to drop the nose and clear the stall) without it being much of a problem. Maximising fuel in orbit is as much about flight profile as shipbuilding; what speed and altitude are you hitting before lighting the rockets? - - - Updated - - - I'm running with both; might be worth a try.

What happens if you try to take off at a lower speed (110m/s or so)? 150m/s is a bit on the high side. Does the nose refuse to lift, or does the nose lift but the plane stays grounded? Are you after something with unrefuelled interplanetary ability, or is it intended to be refuelled before leaving LKO? Either way can be done, but the second option is inevitably going to be a more efficient and "sporty" ship than the first. If you're taking the second option, you can afford to lose a fair bit of tank capacity. - - - Updated - - - The Mk3 adaptors have stupidly low joint strength. Stock Bug Fix strengthens them a bit, KJR strengthens them a lot.

Pics only as requested: I'd throw the station into an equatorial orbit, even at Minmus. Minmusian orbital speeds are so low that inclination changes are very cheap.

Seconded. If folks want to play Star Trek: The Kerbal Generation, they have a wide variety of SF mods to choose from. They also have virtually every other space-themed game ever released. But this game, thankfully, is something different.

...except that the obvious way to close an intake is to push the shock cone or intake ramp all the way forwards. You end up with a fairly streamlined surface. But, yeah, intakes are draggy because the air is slowed, pressurised and fed to the engine; it doesn't just breeze straight through.

Apart from a few special cases, RAPIERs will generally beat turbojet plus rocket. But as a general theme...you don't need a lot of engine if you keep your drag and mass under control. Some examples... One jet: Two jets: Three jets: Four jets: Most of those are, if anything, overpowered (especially the three-jet one; that's a stupidly fast sportscar of a thing). Most of 'em would work perfectly fine even if you took one of the jets away. At the size of plane you're building, I'd probably go for a RAPIER/Nuke/RAPIER combo (like the second example above). A fair bit of streamlining and weight reduction (lose some tanks, lose some wings) to make that work, however. What speed are you taking off at?

Will the operations manual do? http://boingboing.net/2015/05/05/lunar-rover-operations-manual.html

Repost this in the FAR design thread (http://forum.kerbalspaceprogram.com/threads/121176-Official-FAR-Craft-Repository) and you'll get plenty of detailed answers. However, from a quick glance at the ship...something that size should be able to manage on two or three engines. Your major problem is excessive drag rather than insufficient power. Lose the extra intakes (one shock cone per engine is plenty, and those orphan intakes you've got clipped through the wings must be generating insane amounts of drag) and try to rationalise the wing and stabiliser surfaces.

With a 180° inclination change. Smaller inclination changes are done by burning towards Normal or Antinormal; for a 180° flip, however, you're basically just burning retrograde to a dead stop, then accelerating back the other way. However, a low-orbit inclination change of that magnitude requires a huge ÃŽâ€V expenditure. Inclination changes are best done when the ship is moving as slowly as possible: i.e. at apoapsis in the highest orbit possible. At times, it is more efficient to first raise the apoapsis very high, then flip the orbit, then pull it back down again.

Considered a turbojet tailsitter? They're trickier to build and fly than a conventional cargobay/Wheesley VTOL, but there's a huge saving in dead mass. As well as ditching the cargo bay and surplus jets, the VTOL ability also allows you to get away with minimal wing surface.

Notice the huge and numerous fins at the bottom? And the nosecones? And the large supply of gimballing engines? Stock aero or FAR, build and fly it right and you can launch almost anything. If it's a draggy load, you just need to balance out the drag with gimbal and fins.

1) Ignore the tutorials. Build a rocket, watch it explode on the launchpad. Then build another rocket that explodes in midair. Then one that goes suborbital. Then one that reaches orbit. All of this is stuff that can be worked out by trial and error, and it's more fun to figure it out for yourself. 2) Start to expand your options. Fly by the Mun. Crash into the Mun. Land on the Mun. Land on the Mun with something that can take off again. Land on the Mun with something that can return live Kerbals to Kerbin. Again, this is all best done as trial and error. 3) Get serious, look at the tutorials. Learn to go to the Mun in style. Start to expand your range to other planets. 4) Do it inside a budget. Career mode and mods time.

Heavy bits at the front, draggy bits at the back, gimbal is good. That's really all there is to it.

Keen to see what times some stock aero racers can post: http://forum.kerbalspaceprogram.com/threads/123650-Kerbinside-Air-Race

Might be of interest: http://www.aresgames.eu/games/sails-of-glory-line

FAR Kerbal Flight Data Kerbal Flight Indicators Pilot Assistant Dynamic Deflection Kerbal Alarm Clock RCS Build Aid Kerbal Engineer Redux and/or Mechjeb Apart from FAR/DynamicDeflection/PilotAssistant (which are inter-related; the more realistic aero of FAR is what makes PA's PID tuner necessary), all of those fall into the "why the hell isn't this stock already?" category.

Inclination changes increase in efficiency the slower you are moving; so, high orbit is better than low, and apoapsis is better than periapsis. But you can do an inclination change anywhere in the orbit you want; you don't have to wait for apoapsis/periapsis (or the ascending/descending nodes, for that matter, although you need AN/DN if you want to perfectly match orbits). The ÃŽâ€V cost of an inclination correction done immediately after departing the Minmus SoI should be trivial.