RCgothic

Simplified explanation to aid understanding. I offered three different solutions in ascending order of difficulty and reduced fuel consumption. As always, use of manoeuvre nodes does help a lot.

Burning normal/anti-normal doesn't change apoapsis. However, it DOES change which direction normal/anti-normal is in. If you don't rotate your vessel as you burn you will no longer be burning in a purely normal/anti-normal direction and so will be burning a little bit pro/retrograde, which will change your orbital velocity and therefore altitude of periapsis/apoapsis. Choose one of three solutions: -Accept the change in orbital velocity and compensate with a later burn to adjust apoapsis/periapsis. (Easy) -Rotate your vessel as you burn to stay pointing normal/antinormal. You can dynamically compensate for any small error by deliberately burning off-normal yourself. (Moderate) -Guess which angle will be normal at the midpoint of the burn and burn in that direction. Any pro/retrograde vector added in the first part of the burn will be compensated by the second half. (Hard) Hope that helps.

Perfect! I love throwing things out to save weight.

Yes, and I was invited to post a report anyway.

Alright, time to bust these gates wide open! Any consensus over whether using FAR is easier or harder than stock these days? Take off: Orbit: That's about 400dv remaining. Re-entry: Overshot a bit: Sightseeing: Coming in for landing: Touch down! Not so useful payload: One bored scientist. Several hundred unused units of fuel. Now to upgrade to something actually useful.

Burn at apoapsis to adjust periapsis. Burn at periapsis to adjust apoapsis.

It's not difficult to give a small probe an insane amount of dv. What's the payload?

I did, but I used them for braking on the runway once I was down.

I just successfully completed my first SSTO spaceplane mission and only used stock parts. But I suspect I don't qualify for the K-prize because I have FAR installed?

I'm only going on my recent experience in building my first SSTO spaceplane. At 20km and 1200m/s I started to lose control, with the craft wanting to go into a flat spin and then backflip. It was solved by the addition of forward canards (pitch) and a much larger tailfin positioned further back (Yaw). If that's not your issue, then where are you struggling? Not enough dv? - - - Updated - - - I'm only going on my recent experience in building my first SSTO spaceplane. At 20km and 1200m/s I started to lose control, with the craft wanting to go into a flat spin and then backflip. It was solved by the addition of forward canards (pitch) and a much larger tailfin positioned further back (Yaw). Note: small active fins can work well until the air gets thin. but larger fixed fins will still work. If that's not your issue, then where are you struggling? Not enough dv?

A tip is to have both vessels facing Normal/Anti-Normal. That prevents rotation as the craft orbit. Also I don't think re-docking the same vessel undocked counts. I discovered that by trying to dock to a probe launched on the same lifter.

Successful landing! Returned a payload of one passenger and 270 units LF and 300 units Oxidiser. And I flew to orbit with my gear down. Airbrakes on re-entry made all the difference!

I suspect you don't have enough Yaw or Pitch Authority.

Sepratrons are kind of unnecessary. Just spin the rocket up around its central axis before detaching the boosters and they'll be flung away by centrifugal force.

Is "Upgrade your Duna spaceplane to be a Kerbin Spaceplane and refuel in orbit" a valid suggestion?

Thanks guys, all very useful! I'll make sure to double check where all the fuel is and shift it forward before my next re-entry attempt. I suspect the fuselage tasks will be basically empty with the nacelles half-full and I'll need to pump those forward. I may try adding some airbrakes too. It sounds like flaps/spoilers won't be terribly useful for a canard/delta design though as the trailing edges are too far from the COM.

Thanks for the tips. Is there anything to add regarding the use of flaps, spoilers and airbrakes? I.e. how to. What I meant by keeping my periapsis up is generating enough lift such that even though I'm slowing down, periapsis doesn't fall too deep into the atmosphere before I'm properly slowed. I guess I also don't understand why speed and altitude have such a negative effect on stability parameters. Why does Yaw Stability fail? It's not like the nose is getting larger and the tail smaller.

Isn't RCS really draggy?

Hi guys, a little help here? I've managed to get it into a 75x75km orbit with enough L/Ox to deorbit again to about 35km periapsis. Payload is currently only one passenger and about 400 units of Liquid Fuel. Powerplant is two Whiplashes and a Swivel (career limitations). I'm struggling to de-orbit it successfully. At the moment I can't keep the periapsis up and everything ends in a lack of control and a fireball at about 22km. Any hints? I'm not clear on how airbrakes, flaps and spoilers work, so that could be a start. http://imgur.com/a/VGB3w

I built my first SSTO spaceplane (career) powered by 2 whiplash and a swivel and successfully put it in orbit. Payload was only 1 passenger and around 450 units of liquid fuel to 75km x 75km. Unfortunately I couldn't keep it under control on reentry and it exploded at about 22km.

A couple of observations to begin with: 1. The materials bay is heavy. You'll find it a lot easier to get into orbit without it, at least to begin with. 2. You also have too many engines in there. Whenever an engine isn't firing it's dead weight. And the staging apparatus is also unnecessary weight. Delete the engines and decouplers from stages 6 and 7. Merge the tanks that remain with stage 8 by attaching the lower tanks and engines to them. Each of those engines is easily capable of lifting two tanks with sufficient thrust left over to boost the central stack. 3. That central engine needs to be doing some work earlier or it's just dead weight. Select it within stage 4 and drag it into stage 8. It'll only burn 50% longer than the side attached boosters in this config, so give it an extra tank below the stage 3 decoupler. 4. At present you have a fairly long delay between an engine burning out, staging, and then re-igniting the engine of the next stage. This is because there's an enforced delay between staging to protect against accidental activation of a later stage. You also lose the control authority of the engine gimbal whilst it's deactivated and you lose speed. If you drag the engine from stage 2 into stage 3 it'll activate the engine immediately on staging, controlled by the throttle position. Other unnecessary delays have been removed by the other alterations. 5. Try attaching the side boosters higher up, which moves the centre of mass further forward and increases the control authority of your fins. If you can spare the parts for aerodynamic cones for the boosters, that'll help them punch through the air a bit too. Note: The staging numbers will update through all the updates above, but I've referred to them by their original numbers for clarity.

He'd spend eight weeks driving.

Heck, even a picture of your rocket should be enough to point out any major flaws.

I currently have 21. That's going to expand rapidly once I move my communications network beyond LKO.

KER just makes things easier. I'm an engineer too, and I still do real maths. But some things can't be calculated manually in real time. When you're trying to match a specific orbital period it's nice to have KER just spit out an answer after every thruster pulse. Matching orbits exactly is vital to keep a satellite constellation in formation without requiring manual adjustment all the time. My most recent constellation should hold formation for 16000 orbits before its performance degrades enough to require tweaking. Schlock did an issue on this: It's good to know how to do a thing manually. But always doing it that way when you can automate is just tedious.