Wanderfound

Try to avoid wholesale redesigns, but minor revisions are fine, especially if you get 'em done quick so they don't delay the judging. The idea is to find the best designs, not to punish people for failing to notice a symmetry bug or somesuch.

Grab the latest version of FAR (14.3.2: http://forum.kerbalspaceprogram.com/threads/20451-0-25-Ferram-Aerospace-Research-v0-14-3-2-10-21-14): the first few post-.25 releases of FAR were heavily buggy, and the wing strength adjustment didn't come in until after a few bugfixes happened. This is probably the explanation for a lot of the trouble; in response to endless complaints about overly fragile wings, when KSP.25 was released Ferram massively increased both the strength and weight of his wings (and then introduced the tweakable when people started complaining about excessive weight...). If you're flying it under old-FAR, and Alshain and I are flying under new FAR/NEAR, we're not really flying the same planes. Your version has glider wings, our version has fighter jet wings. Ye olde FAR wings are equivalent to new-FAR wings with the mass/strength tweakable wound down to about 0.25 (but I'd actually recommend you go for 0.4 or higher; the old wings were​ overly fragile).

Okay; Wanderfound's [1] review post: It's decent looking little thing; the aesthetics are a touch Star Wars for my taste, but that's just a personal thing. The anhedral main wing is a slightly curious choice; it's balanced by the dihedral tailplane, but a level wing would improve roll stability and give more runway clearance on landing. Easy rotation, effortless takeoff. Minor tailstrike hazard, but easily avoided. No problem in the climb... ...although it does need to flatten out fairly soon to maintain speed. The thrust available is perfectly adequate for the job, but there isn't a huge amount of surplus. The airframe is stable enough for substantial time acceleration, although this does reveal a hint of roll instability and an occasional minor pitch-up tendency. Both issues are easily dealt with at normal time, and not serious enough to prevent time accelerated cruising; they're very minor. It does require quite a large AoA to maintain level flight. As with the thrust, there is enough lift to do the job, but not a lot more. Gets up to speed easily enough. ...and has a pleasing silhouette. Nice short circularisation burn, too. Plenty of fuel still in the tanks. ...and I hadn't even realised it was carrying a payload. Nice. A laptop crash stopped me there; I'll take it through reentry and landing later if I have the time. One thing of note: the wing strengths are all set at default (1). It works fine as is, but winding that down to 0.4 or so would make it a lot faster and more nimble, while still retaining a generous amount of strength. However, it was designed for NEAR rather than FAR; I'm not actually sure if NEAR allows adjustment of wing strength or not. It also appears that the spoilers are non-functional. I think they're set to the same control surfaces as the flaps? If so, that would be why; they don't work if set both ways. Resuming test: Comes through reentry easy enough if you keep an eye on the AoA. However, the pitch-up tendency does make it a touch tricky; too much AoA and you'll find yourself in a longitudinal flip. The airframe is tough enough to recover from this if caught in time, however. Glides comfortably enough, unfussed by high dynamic pressure. Troubles set in on landing approach, however. The pitch-up tendency is aggravated in the dive; even with full negative trim, it simply refuses to keep the nose down unless constantly held, and pitches up sharply any time a roll correction is applied. This makes it rather difficult to maintain low-altitude level flight while adjusting bearing. Extending or retracting flaps did not solve the problem. Although you can force it down, it is difficult to do this while still keeping the sink rate at safe levels. I bounced off the runway a few times before getting it down. I did eventually manage to get it down and hold it there... ...but not in time to have enough room for braking. Still, any landing you walk away from etc. An imposing beastie on the ground. And not short of power. There doesn't appear to be an action group set to toggle the RAPIERs on and off, however. It rotates easily enough; the gear are placed correctly. But as mentioned in the entry post, it does require the entire runway to lift off. A lot of this is due to the fact that it is heavily oversupplied with wings, and all of those wings are still set to full default strength and weight. As above, cutting this down to 0.5 or lower would save a huge amount of weight, while not overly impacting the airframe durability. You don't need full strength wings unless you're planning on high-g aerobatics at low altitude. Despite the max-strength wings, there is still a huge amount of wing flex. Partly this is due to the high weight of the craft; partly it's due to the rather excessive wing area. You could deal with it via strutting, but you'd probably be better off just going for smaller wings and reducing the overall weight of the ship. Unfortunately, I also had a lot of trouble getting this one to fly successfully. The airframe has substantial handling flaws... The major handling issue is related to yaw control; the plane has a huge amount of yaw authority, but very little yaw stability. It has a tendency to drift off line, and it is difficult to counteract this without over-correction. The extreme dihedral on the vertical stabilisers (AKA tailfins) robs them of much of their power, and the X-wing pattern canard rudders near the nose actually reduce stability rather than increase it. As a general rule, stability and manoeuvrability are opposite sides of the same coin: helping one usually hurts the other. As another general rule, rear-set aerodynamic surfaces are good for stability, forward-set aerodynamic surfaces are good for manoeuvrability. Think about the position of the feathers on a dart or arrow. When the plane goes off line, rear surfaces pull it straight again, but forward surfaces pull it further off line. The other main concern with this craft is the biplane design. We don't see a lot of modern biplanes, and there is a reason for that. The downsides of a biplane are extra weight and drag compared to a monoplane with equivalent lift. The main upsides of a biplane were reduced wing loading (important when wings were made of cloth and wood, less so these days) and the ability to tolerate extremely low speed (i.e. 50mph) aerobatics. Neither of these things are major priorities for a high-tech spaceplane. It's possible to make a biplane spaceplane work, but there isn't much reason to; you'd always be better off with a monoplane instead. Layered wings work well in stock aerodynamics, but not so much in FAR/NEAR. Still an imposing visual presence, albeit a touch more conventional than V1. Previous wing-flex issues are now entirely non-existent. Takeoff behaviour much improved. It does require a bit of speed, but given that speed it both rotates and lifts off easily. No trouble pulling into the climb, either. Much improved aerodynamics; no instability problems at all. ...even under time acceleration. Excellent stability. No difficulty getting up to speed. The requirement to keep at least four engines running at all times does rather limit the jet-powered flight ceiling, however. A bit of an overheating tendency in rocketry mode, but easily controlled by easing the throttle a touch. Easily makes orbit. And a decent cargo capacity, albeit somewhat impaired by the intruding RCS tanks. The quantity of RCS storage does seem highly excessive; there's enough here for a dedicated RCS tanker. This is particularly odd given that the extreme levels of torque available from the numerous SAS units means that the only time that RCS would be required is during docking. A reasonably easily accessible docking port; no risk of tailfin collisions. I wouldn't want to try docking two of them together, however; the landing gear are likely to get in the way. Plenty of juice in reserve. Handles a DRE reentry with no hassles at all. Very user friendly. Again, the inability to deactivate the RAPIERs and fly on Turbojet alone is a weakness. As well as sounding nicer, the Turbojets are more fuel efficient. Able to tolerate a bit of rough handling; no problem with moderately high dynamic pressure and g-forces. Easy atmospheric flight handling; neither too much nor too little control authority. Not an aerobatics plane, but not intended to be. Easy landing and approach behaviour, although a surprisingly high stall speed given the large wing area. A consequence of the high weight of the ship. Down safe. However, it wasn't until I'd hit the strip that I realised that (a) the steering on the front gear was still locked, and ( the brakes on the front gear were still enabled. Neither of these things are as they should be; an inexperienced pilot would be at substantial risk of runway disasters. Overall: vastly improved. What we have now is a perfectly functional spaceplane that is pleasant to fly and gets the job done. However, there is a general theme in the design that all problems have been overcome by the strategy of "more" rather than "better". More wings, more engines, more SAS, more RCS, etc. It works, but the consequence is a spacecraft that is much bigger, heavier and more expensive than it needs to be. Still: not bad. You're getting the functional basics down; the next step is to start working out how to get the functional effect while also invoking efficiency and elegance. [1] Wanderfound should probably resist this habit he's recently acquired of referring to himself in the third person.

Some other review response tips: * Wait for a few reviews to come in. An issue reported by one reviewer may not exist for another, clarifying whether the problem was piloting-related or not. Quite often, the reviewers will differ in their opinions, and that's okay. * Feel free to point at screenshots demonstrating the capabilities of the craft. For example: (did you have the SAS on? The wingtip mounted landing gear leads to a bit of wingflex-induced steering, which the SAS can correct for) * If you feel that piloting style is negatively impacting your reviews, try clarifying your flight instructions. * Try to resist the temptation to dispute the reviews too much. Remember firstly that the reviewers are also the voters, so you don't want to get them offside; and secondly, we're all doing this for fun (and maybe to learn a bit about spaceplane design).

Whoops, chain reaction. Didn't look at the dates far enough upthread to spot it.

Doesn't bother me; I don't see any reason why not.

There's a couple of ways around it. The simplest is to first attach a Mk2 fuselage part that doesn't have this problem (e.g. any of the fuel tanks, but not the bicouplers) and then build the cargo bays off that. And, of course the Kerbal cure-all: cubic octagonal struts, which is what I suspect DasValdez has done. There are simpler ways to use cargo bays in vertical rockets, however. Just build the whole thing out of Mk2 bits:

See the spaceplane landing guide in the second post of the Kerbodyne thread linked below. S-turns, loops, climb/dive cycles, airbrakes, etc. Be aware that the thin atmosphere of Duna is going to make slowing and landing much more difficult. Most folks landing on Duna will do it via parachute (and lots of 'em, due to the aforementioned thin atmosphere).

BTW: if possible, try to accompany each review with at least one screenshot, so that readers can more easily keep track of which plane you're discussing without having to flick back and forth. If you're at all like me, I find it a lot easier to recall images than names. And, keep in mind that the critique is directed at the plane, not the designer. Try not to take it too personally when people criticise your babies. (everything cool so far, just getting in with some preemptive diplomacy before the bulk of the reviews show up)

I kind of did that in reverse; I landed a six-seater spaceplane on the Mun to fulfill a base contract, with the intention of immediately returning to Kerbin. But I wasted a bit more fuel than I'd intended looking for a good landing spot, then I realised that I didn't have enough left to get back into orbit... They're still there. They've got a docking port, but getting a refueller to dock with a Mk2 inline port while the target is sitting on the ground is going to be...challenging. Yeah, KAS fuel hoses etc., I know. But where's the fun in that?

BTW: I'm also doing a last-minute run through my designs looking for symmetry-induced action group bugs and the like. I've already found a couple; I'll replace the downloads with the corrected versions once I'm done in an hour or so.

Yup, as with Sirine's previous contest. Pics and polite criticism good, but keep to the guidelines re: spoiler tags and image sizes. Convert to JPEG if possible.

...because all of that is game-balance and final-polish stuff that they've always stated is going to be left for after scope completion (i.e. after .90 comes out in a few months). And this is for sensible reasons: there's no point in expending a lot of effort into balancing the tech tree before the parts list, funds and science-gathering systems are finalised, because you'll just end up having to repeat the job after you do. The game development so far has been about reaching scope completion; i.e., making sure that all of the necessary ingredients are in the cupboard. Now that that is just about done, it's time to bake and decorate the cake. The oven is warming up right now.

You can get that sort of shape to work in stock, but you'd struggle to make it fly well in FAR (because you'd need to fake that wing shape by stacking layered wings together, which FAR will interpret as a badly constructed biplane rather than a single funny-shaped wing). You can definitely do lifting-body ships in FAR, though. But you need to do it by using body parts with lift (e.g. Mk2 fuselage pieces), not by hacking something that looks vaguely appropriate together from repurposed parts. See the Kerbodyne Lancer for an example. As for control-without-control-surfaces: hard, but possible. Lockheed (and B2 bombers etc) do it by the use of differential thrust: basically, if the plane starts yawing right, the flight computer cuts the left engine's thrust a smidgeon. This is possible to do in KSP, but very very very difficult. The easier way to approximate it would be via heavy use of Vernors and lots of SAS torque. Alternately, get super-cheaty and use part clipping to hide some control surfaces inside the wing (this will work in stock, not sure about FAR).

O The excess wing mass is probably a large part of your problem: at the moment you're carrying extreme high-G aerobatics wings. Those things aren't intended for space. Vernors are super-powered linear RCS ports that consume LFO instead of monoprop. What they give you is the ability to put a small thruster anywhere you want it, and have the RCS system handle the task of controlling them for you. So, if you're having trouble lifting the nose: stick a Vernor on the underside of your cockpit and/or the top of your engines. If you're having yaw stability issues, stick one either side of the cockpit and/or engines. If you're getting uncontrollable pitch-up, stick 'em on the cockpit roof or under the tail. Etc. They won't consume any fuel so long as you keep the RCS toggled off, but as soon as you toggle it on it will start adding its force to any manouevres you make (or will try to hold your direction constant if you aren't maneouvring and have SAS on). Stick enough Vernors on, and you can stabilise a brick. Keep them turned off as much as possible, but flick 'em on for a bit any time the ship starts to misbehave. See the things just in front of the canards on this ship: Those are Vernors, which I have turned on (by toggling RCS on) in that shot because I'm flying at an altitude where there isn't a lot of aerodynamic grip. I frequently put them on my craft even if they don't need them for stability, because they also make good low-gravity VTOL jets and may allow you to recover from an otherwise incurable spin or stall. They're also handy for stretching the envelope of possibility when indulging in extreme aerobatics. Just don't try to dock with 'em on; they're too powerful for the fine control needed during docking. If the ship is intended for docking, add conventional RCS as well and use an action group to toggle the Vernors off. Okay, first up, you're switching from jets to rocketry much too early. You want to run the jets on their own for as much of the flight as you possibly can. So, don't switch to rocketry as soon as the jets start losing power; save the rocketry for when the jets are completely incapable of producing thrust at all (i.e. flameout). At the time the rockets come on, you want to be doing at least 1,500m/s at an altitude of at least 30,000m. Have a read through the piloting guide in post #2 of the Kerbodyne thread or listen to my piloting tutorial on the latest episode of the Kerbal Podcast. The loss of control immediately post rocketry is most likely the plane reacting to the sudden change in thrust and the alteration of gimballing ability. Use the right-click tweakables to turn the thrust limiter to zero on the jets, then use RCS build aid to check your engine-induced torque from the rockets. Then turn the jets back to 100% and the rockets down to zero and do the same for the jets. Just because all of the engines together are balanced doesn't mean that the jets or rockets are balanced on their own. Yes. I haven't tried this one yet, but it also includes a PID controller: http://forum.kerbalspaceprogram.com/threads/100073-0-25-Pilot-Assistant-0-2-Nov-15

BTW, a few of my recent entries were put up in a hurry, without action group instructions etc. I'll fix that today.

In FAR, take your cues from reality. In stock, try not to trip over reality's rotting corpse as you step past it. For a nice demonstration of just how little influence real aerodynamics have on stock, see http://forum.kerbalspaceprogram.com/threads/93779-SSTO-Spaceplane-Airplane-Design-Contest-II-Akademy-Awards?p=1416715&viewfull=1#post1416715 Stock aero planes typically carry more wing, more intake and more engines. However, I'm not the person to ask for stock design tips; I don't do that often enough to give good advice. Checking out some of the stock aero planes in the Akademy Awards thread should be useful, though.

AFAIK, the two nacelle types are functionally identical. I'm quite fond of them; as well as the extra intake, they also provide a useful little bit of pure LF storage so that you don't find yourself with surplus oxidiser in orbit. And they make for handy engine and shock cone mounts: The other consideration is: FAR/NEAR or stock aero? In stock, load up on intakes and get crazy high and fast (if you want, it's not compulsory; you can make perfectly good stock SSTOs with <1 intake per engine). In FAR/NEAR, don't bother: no matter how many intakes you put on, you're not going to get any faster than about Mach 5.5 until you light the rockets. More intakes than you need is just wasted weight and drag. As does Kerbal Flight Data:

Finally got the car sorted out; still working on the perfect run, but 1:30 is looking possible... Keep running wide on the tight left-hander before the VAB, though.

If you're burning evenly, they should be draining evenly. Most likely, you have a misplaced fuel line somewhere.

Isaac Asimov. (yeah, okay, Hari Seldon...you started it...) What was the name of the computer in the last season of Blake's 7?

Look upthread. Most probably, you're in the correct orbit but going in the wrong direction. If you look at the orbit in map mode, there are little markers whizzing around to show the correct direction. - - - Updated - - - Only if the lander has rover wheels.

It helps to remember that control surfaces are levers; the further they are from CoM, the more power they have. Ditto for horizontal & vertical stabilisers. Therefore: long fuselage for pitch and yaw stability. As for wing size...in FAR, take your inspiration from reality. Sure, 747's have big wings, but they don't go at Mach 5 and they don't go to space. These planes do (almost): Notice the lack of big wings?

Uncontrolled pitch-up is most likely caused by insufficient longitudinal stability, not insufficient lift. Run an AoA sweep at the speed at which you tend to lose control; if your Cm line inflects up, that's the point at which your craft is going to try to flip backwards. If you post screenshots of the FAR analysis screens here, we may be able to identify the problem.

Also, BTW: the SAS wobble is due to the SAS overcorrecting because it's expectng rocket levels of control authority rather than the much stronger forces a plane generates. As the air thins, your aero surfaces reduce in power, which in turn reduces SAS wobble. By the time you get to rocketry altitude, it's probably safe to turn the SAS back on.