ajburges

The reason canards offer such good maneuverability is because many designs place engines and significant fuselage sections in back. This in turn moves the CoM way back. Since the CoM is far back, any forward control surface will have a ton of control authority. Since control authority can be visualized as shifts in your CoL, this also explains why they can cause you to leave a stable flight envelope if you get too aggressive with them. As I mentioned earlier, if you lack control authority, your CoM is not well balanced for the control surfaces you have.

What most people gloss over is that if you can't pitch-up, your stability is overpowering your control authority. This is why you see the suggestions of both making the craft less stable and increasing control authority. The actual answer depends on desired craft behavior. If you want your craft to be more resistant to stalls, you keep the high stability and add/move control surfaces for control authority. If you want your craft to be more efficient, you reduce aerodynamic stability so you need fewer control surfaces (which add drag). My light and medium space planes tend towards less stable craft. Larger planes tend towards more stability since that is more tolerant of control mistakes (due to physics lag)

Yes pitch authority is a function of the torque your control surfaces generate. Torque is a product of force and distance from CoM. Technically any pitch or yaw surface can contribute to roll. Since drag is proportionate to just force for control surfaces, you want to stick them out as far as possible for efficiency. This means that you typically don't want to use pitch and yaw surfaces for roll because they are too close to the body.

Once my Ap hits 50 km I ease off the throttle. Drag is negligable that high (at most -12 m/s dV) so you can really drag out your gravity turn to really minimize gravity and/or cosine losses. Most my craft need 20-40 dV circularization burns. If you need a long circularization burn, you either are short on TWR or you need to revisit your ascent profile.

I don't think he is. I think he is proposing a long transfer to Kerbin. Eject and wait until the minimal difference in period causes you to enter on the opposite side of Kerbin SoI. You can do a correction burn a quarter orbit to SoI change.

If you are in a circular orbit that far out, you are doing something wrong. A 80 x 47000 km orbit around Kerbin gives you a speed of 45.72 m/s at Ap (period of 110 hours) (921.19 m/s to boost Ap). Near SOI boundary with a 80 x 80000 km orbit around Kerbin gives you a speed of 27.08 m/s at Ap (period of 241 hours) (930.45 m/s to boost Ap). A gravity assist around a Moon is generally preferable because the dV is pretty good for the time it takes.

Nonsense. Just use launch clamps and rotate the ship. Staging/throttle is a bigger problem.

That was clever in .90, in 1.x that could be a nightmare. Putting your launch fuel ahead of CoM makes balancing CoP more difficult. The best advice I can give for vertical launch space planes is to maintain symmetry. A single fuel tank is hard to balance CoT and CoM. Adding drag to that makes it even harder. Also, unless you want to model STS or Buran, consider why you are doing VTHL. Faster ascent, increased final stage recovery fraction, or higher payload capacity? Each of these possibilities guides you to different design paths.

Unless your crazy, yaw instability in a turn should be a non-issue for landing. Looking at the vectors, your CoP is ahead of your CoM at high speed due to body lift. Do one of the three: > limit high speed AoA > add more horizontal stabilizer > reduce control authority

Obviously. You craft can still make a good marker of not enough dV though. I must admit, when I started my design, I assumed you would keep your craft to high atmo. I was sure nothing that small could have enough dV to get back out from low atmo. Of course, now I have an even crazier idea for a reusable staged Eve launch system. Need to see how much dV I can eek out of two stages.

Can't wait for the behind the scenes stuff. Your craft are an inspiration for my game. My first Duna window has a Humblebee inspired plane that will stay on station for science and surveys. It is definitely the flagship mission. My initial Eve exploration will rely on a nuclear powered dipper for high atmospheric science. I'm saving low atmo science for another craft as the dV requirements for return from angels 20 (low atmo boundary) were crazy if I allowed the craft to decelerate to 1.5 km/s for thermal profile. Nukes are still more efficient than spikes that high, but the tyranny of the rocket equation was starting to show up and without the first mission, there were too many unknowns about performance. I may punt and design a rocket plane for low science and a conventional lifter for crew/sample return. I'm dieing to see your craft's stats. Gha! How do you add more rep in mobile view?

The nice thing about keeping refueling stations in each major SoI is it makes it feasible to run irresponsibly inefficient (but fast) transfers. Your crew ferries and contract modules can really optimize for arrival time over dV cost. Even if you start mining the fill-up after the craft's departure burn, a full thank will be ready when it arrives and you can immediately return said craft to Kerbin! It also frees up launch windows for more massive projects like stations and the mining system itself. Building a refinery system on Minmus/Mun may be a wash financially, but it makes a good proving ground to test your ideas. Every major SoI has a low mass airless planetoid to mine on. Beyond building the obvious gas stations, mining allows for some fun landers. Check out Kuzzter's work. Especially "Duna Ore Bust." Rocket planes on Duna can actually make surveys novel for a time.

Disable rudders eh? Interesting concept and a good way to stop novices from trying to change heading with yaw. Still, the ability to vary AoA means you need less stabilizer if it is also a control surface. It's also nice for correcting inclination as you transition to ballistic flight. Even a passive stabilizer will induce roll while slipstreaming if it's unbalanced. I find that you need surprisingly little yaw stabilization for most craft if you are careful during reentry and avoid high slipstream manuvers. A single winglet is enough to keep my 60-80 t craft stable. This can be mounted on the centerline with a very small proportion of asymmetry.

Airworthiness is complex to test. A full fuel landing tests both your structural integrity and abort options. Pulling out of a high Mach dive tests (with heavy load) wing loading. It's important to know what your wings can handle so you know when it is safe to begin aerodynamic fight after reentry. Finally and hardest, you want to judge low lift stability. Drag is a significant force for much higher than lift. Some craft are aerodynamically stable only until a certain height. A mistake while it is in unstable phase can put you into a flat spin. Thankfully this often is high enough that recovery can be done easily, but it still mucks your trajectory up. Of course it is also important to tune craft performance. Space plane ascent is more involved than rockets. If it is a pain to fly, you won't.

I also find that angled rudders introduce unwanted roll even when all the tips are followed. SAS is a horrid substitute for a fly by wire system. Having the rudder plane tangent to CoM should give it no roll authority, yet it still rolls for me.

Actually, I had a fun little Minmus biome hopper in .90 that ran off a single Dawn for surveys. Ion utility is really hurt in 1.x because of lack of Xeon refining. All Xeon needs to come from Kerbin while a local refinery can provide the fuel for reusable Monoprop and LV-1 probes. That means Ion engines are only optimal for one way and/or long range missions. Otherwise, they are too expensive and/or too low powered. Another complication of Ion engines is power draw. Any solution that is not "burn with solar panels in the sun" requires extra weight and/or crazy Pe kicking. My probes often use a gravity turn around the Mun to avoid burning in Kerbin's shadow. Tip: ox-sat panels have a better power to mass ratio than Gigantors.

Tip: you can set a KAC alarm for when you reach a distance above a body (in the rendevous tab). I use it all the time for aerobrake alarms, but if you set it a touch over the highest peaks of a planetoid you will always get a notice before it crashes.

I use the trajectories mod to guage decent above 18 km. Reentry has too much ranges too early for flags to help and if my reentry is good, I can maul the plane into a great (all parts survive) landing on the runway. Did I mention Jeb is a huge fan of my space program? (at least until we get stock flight computers)

Pedantic: there is a couple seconds difference in latitude between the two ends. It's not much, but it points southwards which adds to the inclination you get from it being 3 minutes south of the equator. - - - Updated - - - Being constructive: I find glide slope is heavily dependent on the craft. One of mine had a 20° slope! Of course, that may be because I like a faster glide. Regardless, I find gliding in boring. Most my craft have enough wing loading and control authority to pull out of a 200 m/s dive to level flight. Unless your craft is less aerodynamic than a brick, 200 m/s should give you a couple of klicks of near level flight. This requires non-trivial lift however. A minimal lift rocket may not be able to control a dive. The runway is the friendliest landing surface in the game. Even so, I like to touch down with less than 160 m/s.

I find that the service bays I spend the time to develop into a sub assembly never have an issue. I have one with a core batteries solar panels, and 6 parachutes that tops every one of my rocket lifters. Those 6 parachutes are for tip control. The landing chutes go on the body inside the fairing. If I stick some stuff in one for a one off mission. That craft will have the shakes man.

Most space planes have plenty of drag for safe reentry. At angels 7 terminal velocity of a good rocket stack is over Mach 3; it's about Mach 1 for a space plane. Most issues with reentry can be traced back to bad decent trajectory. (sometimes entering heavy can also contribute) On struts. Those things are like parachutes. I only use them to stabilize landing gear, SRBs, and payloads (occluded from drag) these days. If the gear needs more than one each or my wings flex, I revisit the design first.

If you don't mind clipping, you can mount the struts directly between parts. Just put the camera in the ship in the SPH. It has the added benefit of needing no symmetry, so you keep the part count down.

Radial parts kill drag. If it's not wings, gear, or airbrakes, it belongs in a cargo bay. Jokingly: you could probably do without those items to. A two RAPIER flying sausage can lift a surprising amount of payload. Set CoL balance for minimal craft stability. Stable craft need pitch authority to maintain AoA. Control surfaces induce drag. Also less stable craft need fewer surfaces for good attitude authority. Fly a faster ascent. Lift is proportional to v². You can use less lift off you fly faster. RAPIERs also prefer a fast ascent anyway.

Forgive me if the info is elsewhere, my Google Fu has failed. Is there an easy way to move subassemblies between custom groups? Is there any way to reorder custom assembly and part groups?

The class E ateroids i'm looking to grapple are a little larger than 4t