Virindi

I have an interesting 'problem' and I am not sure if it is caused by FAR, B9 intakes, or the game itself. When I switched from 0.22 to 0.23, the flameout point for jets (vanilla turbojet) moved WAY up. A spaceplane that in the past flamed out at 25km can now run at full throttle at 32km, so almost zero deltav is needed to circularize. My spaceplane has one turbojet and two B9 "divertless supersonic inlets". It is now easily able to top at 2400m/s in the atmosphere, where before top speed was 1500m/s with the exact same plane on KSP 0.22 and FAR 0.11. Also possibly noteworthy, Mechjeb's flameout protection utility still attempts to throttle back at 25km as if the old flameout point was still there. Any idea what is going on? EDIT: Here are a couple screenshots of before and after flameout. Note the 'air req met': 10.2% and the engine is still running.

I have personally found that the most effective way to land on Laythe is with an aircraft. This is mainly because it is hard to avoid the water with such small landmasses, and much of the land that you do have is mountainous, so your landing target has to be relatively precise. Any SSTO that can make orbit around Kerbin can likely make orbit around Laythe, and there's no reason you have to even use one that works on Kerbin. Just make sure you have a large amount of wing area for the weight so you can get your landing speed really low. If Kerbin is a problem, launch it from there on top of a rocket.

They are from B9.

It is quite possible to build an ME-262 configuration* aircraft, at least with FAR. Vessel: ME-262 Mods used: FAR, B9, StretchyTanks, KerbPaint, Procedural Wings Engines: 2x TFE731 TWR: 4.23 Craft file: http://www.virindi.net/junk/ME-262.zip Piloting notes: -Enable SAS. Start at 2 clicks above 0 throttle, rotate at 50m/s. Once you are airborne slowly increase throttle and retract flaps. Sea level cruise throttle is 1/3. -To land, set throttle to 1 click above zero. Extend flaps to full. After touchdown, tap the brakes...if you hold them down, the aircraft will tip. -Handling in the air is about what you would expect from a jet fighter, but it is stable and very difficult to spin out of control *Yes, I know the real ME-262 did not use pitch stabilators. They just fit best.

By the way, if you want to design a successful tailless aircraft with less of a sideslip problem, I believe the key is to watch chord vs. span. A wide, flat object is much more inclined to yaw than a long thin one, and FAR appears to correctly model this. I recently built a tailless spaceplane, and sideslip is almost no problem at all. You barely notice it. Compare: Vehicle: B9 Centauri (modified) Scaled Chord: 4.1m Scaled Span: 4.5m Span/Chord: 1.1 Vehicle: X-36A Spaceplane Scaled Chord: 3.0m Scaled Span: 1.9m Span/Chord: 0.63 By keeping chord larger than span, you should naturally induce the craft to point prograde in yaw. If the span/chord ratio is greater than 1, you should be pushed outward. Incidentally, the logical conclusion from this is that for vehicles WITH a vertical stabilizer, the size of stabilizer needed is proportional to the width to length ratio. Since large vertical stabilizers on spaceplanes are bad for several reasons (wasted mass, mass offset towards the top of the vehicle, etc), this would indicate that an important quality of spaceplanes is that they are long and thin. Disclaimer: I am not an aerospace engineer

There are several problems you might be having with the Centauri. The stock model is possible to fly if you enable RCS and SAS, keep your speed under 100m/s, and do not deviate more than a few degrees from prograde at any time. Something that is easy to solve is the overabundance of roll authority, which causes SAS to 'freak out'. Set the wings to pitch control only and let the thrust vectoring deal with roll alone. This is the single best change you can make. Since it lacks a vertical stabilizer, it attempts to make up for it with RCS. But since it has such a high TWR, it is easy to go so fast that the RCS and wheels are overwhelmed, and you tumble in yaw. Unless you 'cheat' and add a vertical stabilizer or significantly alter the design, sideslip is always going to be annoying. But, it is manageable. Finally, moving the wings back a bit and adding weight to the front can give you more stability without significantly altering the design.

I only make planes with FAR now, but it seems like there is something you may be missing: lift. If (effective lift)/weight is too low, your angle of attack will need to be too high even at decent speeds. Your spaceplane looks very similar in configuration to one of my most successful designs. Vessel: STC-3A "Genie" Engines: -2x Turbojet -2x LV-909 -1x LV-N Intakes: -4x Ram Intake Full Mass: 37.5 metric tons Jet TWR (Kerbin, fully loaded): 1.09 Rocket TWO (Kerbin, fully loaded): 0.44 Cruise DeltaV (LV-N only, vacuum, fully loaded): 8027 m/s Wing area: 120.2 m^2 (equivalent to 16.7 stock delta wings) Wing area to Mass ratio: 3.21 Resource capacity: -LiquidFuel 2160 -Oxidizer 2640 -MonoPropellant 80 Clipping: None

No FAR control features were enabled. MechJeb continuously attempted to turn the rocket away from the proper course, smoothly, the entire time. In multiple tests when this happened if I disabled MJ and manually turned the rocket towards prograde, control was easily regained. If I turn MJ back on, it instantly starts spinning the rocket in the wrong direction again. Note that MJ also does this with corrective steering off. When I manually fly an identical ascent profile (using the navball guidance) there is absolutely no issue.

What about a spaceplane using the kethane turbine engine? I haven't actually tried it yet, but the thing is really efficient if you happen to have a bunch of kethane in your vehicle already.

This idea inspired me, but lifting bodies are annoying. So I did something a little different: no vertical tail or rudder (with FAR of course!). I copied the real-life MD/Boeing X-36 prototype aircraft. Yaw control is provided only by thrust vectoring and reaction wheel torque. There are no hidden control surfaces or wings that you can't see. I was shocked at how well this design actually works; sideslip ends up being a nonissue even under completely manual control (SAS off). As a bonus, the lack of tail reduces drag. Rudders are for wimps!

The fact that all these craft are balanced is quite impressive.

I've noticed that when turning to a heading, it will often try to move pitch in the opposite direction of the target while at the same time attempting to roll, and yaw towards the target. For instance, if the vessel is facing compass 90 pitch 0 with roll 90, and it targets compass 90 pitch 45, it will start by full yaw left, full roll left, and full pitch up. This causes it to get into a corkscrew type motion around the target. Depending on the vessel's mass distribution in w/h versus forward/back, it can be minor, annoying but hit the target eventually, or divergent shooting off into an uncontrolled spin. On some short and very wide vessels, mechjeb simply cannot be used; anytime it tries to turn to a marker, it spins out of control. When attempting to face a target, why does it roll at all? Simply attempting to hold roll while treating pitch and yaw independently based on the current orientation would yield much better results than it currently gets.

Nice small craft! It's good to see spaceplanes that don't have 100000 intakes clipped on to one attach node.

Ascent guidance seems to have a bug wherein it starts trying to face the rocket retrograde, or at least 90 degrees off from the correct direction. This happens even when there is only one command pod on the ship plus a mechjeb case, and the mechjeb case is facing up. Ascent guidance points in the correct direction for awhile, but at some point after starting the gravity turn it suddenly goes crazy and starts steering the ship wildly in the wrong direction. This only happens on some ships, and only some of the time. Most ships work perfectly. When my large first stage separates, the behavior stops immediately. SAS or controlling manually easily keeps the rocket on track. I caught it in action. At the first screenshot, things are going normally. Note the prograde marker is close to the navball guidance marker; everything is pretty much on track. In subsequent screenshots, note the direction MJ is attempting to thrust in: the opposite of what it should. Mods: RealSolarSystem, KW, StretchyTanks, Engineer, FAR, etc. MechJeb 2.1.0 downloaded from this thread. Edit: I tried without corrective steering and got the same effect.

Tired of puny rockets? Used to orbiting piles of Rockomax orange tanks to fuel your interplanetary missions and want to continue doing it in realistic rescaled mode? I give you: the RLS-1. It's one and a half times the mass of a Saturn V (and one third the payload...but the Saturn V upper stages have engines which get 421s Isp). Vessel: RLS-1 Payload: 1x Rockomax Jumbo-64 Orbit: 250x250km Launch Mass: 4383 metric tons Payload Mass to Orbit: ~38 metric tons Liquid Stages: 5 Stage Configuration: 2+2+1 asparagus, two upper stages Engines: -4x Globe X-5 HT SRBs -2x KW Griffon-G8D and 1x KW Griffon XX per booster -4x KW Griffon-G8D and 1x KW Griffon XX center stage -KW Titan T1 4th stage -KW Vesta VR-9D 5th stage Total Pad Delta-V (Vacuum, Mechjeb): 10746 m/s Stage Delta-V (Vacuum, Mechjeb): 924, 224, 1792, 3118, 3581, 1108 Stage TWR (Mechjeb): 1.25, 1.50, 1.10, 0.95, 1.09, 1.00 Orbital maneuvering capacity: 270 m/s DeltaV Ascent profile: Turn start 0, Turn end 200, Turn shape 100%

Another option for the actual Mun landing is to thrust normally like a lander until you are hovering right above the ground, then use RCS to tip over on to the landing gear. I did this in my stock engine spaceplanes mission because the legs on the back were too narrow for the slope. In that mission I did not dock with a space station to refuel; rather, I launched one large carrier plane with a smaller lander plane on the top. Both planes then independently landed at the KSC runway at the end of the mission. I used B9 spaceplane parts (only stock engines were used) but you could do exactly the same with stock parts.

Try turning off the VES info. I have the same issue.

I used a design similar to yours to make an "Atlas V" to launch an "X-37". For it to work, the X-37 has to provide approximately 1500m/s of dv at the end of the orbit burn. I also used four SRBs (the real X-37 does not need SRBs on the Atlas to launch). Landing at KSC on Earth-sized Kerbin is quite a bit more difficult than it is in stock! Without the precisely measured landing paths they use in real life, it would probably help a lot to have a small jet engine on the spacecraft. Vessel: X-37B on Atlas V 541 Orbit: 250x250km Launch Mass: 627 metric tons Mass to Orbit: 4.4 metric tons Liquid Stages: 2 + payload stage Engines: KW Griffon XX, Rockomax Mainsail, KW Vesta VR-1 Total Pad Delta-V (Vacuum, Mechjeb): 12894 m/s Stage Delta-V (Vacuum, Mechjeb): 2467, 580, 5201, 4646 Stage TWR (Mechjeb): 1.33, 2.07, 1.01, 1.89 Orbital maneuvering capacity: 3100 m/s DeltaV

Impressive! When the counterbalance SRBs run out, do you have to transfer fuel or anything? How well does the thing fly in landing mode? I don't see any landing gear

I am attempting to replicate your rocket and failing. I can't get much above 8600 vacuum deltav with a 0.2t payload, and it is really unstable at launch under mechjeb control (I did set the fins to roll control only, which helped a little). What is your upper stage engine? What is your propellant capacity for each stage (I am just using KW tanks)? What is your vacuum deltav for each stage? What sort of gravity turn profile are you using? The best upper stage deltav I am able to achieve is with a mainsail attached to a long 3.75 tank (10935 liquidfuel), at 6132 deltav 1.07 full TWR. The first stage is powered by a Griffon XX as on yours, and I can get as much as 1883+1276 (1772+954 sea level) deltav if I keep stacking tanks until the TWR is low but it never gets enough to hit orbit (it does get really, really close). Note: in the third pic, asparagus staging is not used in an attempt to make the vehicle more realistically plausible.

Did you use another mod to change the impulse of the engines? Because that rocket looks ridiculously small otherwise...

This mod is pure masochism. It took me something like 15,000 delta-v to get a small craft into solar orbit. My biggest issue was rockets being so big that they can't be held together without flipping all over the place. In other words, this mod is pure awesome Now I want a Laythe colony.

Well, not exactly. Due to the low TWR you get from LV-N, the purpose of the SABRE rocket mode is to just kick you up so that you can linger in space long enough for the LV-Ns to pick up your speed. If you use only LV-Ns you will be unlikely to get enough TWR in your vehicle to get above the atmosphere at all like this. I'd call this the 'lazy' spaceplane ascent profile

Try doing it the other way around. That is, if you were attaching the top one first try doing the bottom one first, or whatever.

You can also easily make a quad LV-N drive section by attaching the engines through cubic struts and leaving the bottom of them unattached, then running a structural member through the middle to a decoupler on the next stage. Keep in mind that, like in your picture, when you try to attach the bottoms of the 3 engines the way you have to a splitter, only one of them actually attaches anyway.