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About Spricigo

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    Rocket Machinist

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  1. "Best" TWR Values>

    Yet another issue with suggesting a 'best' TWR is the inability to cover all possibilities of how that TWR will evolve. SRBs on light craft? TWR raise superfaster. Dropped the boosters? TWR decrease instantly. Large craft with heavy payload? TWR will increase slowly. The list goes on, there is just so many variable to consider it all.
  2. To be fair you shouldn't go that much horizontal. Without lift, is thrust that provide the upward momentum to get you out of the atmosphere. OTOH , given Laythe's atmosphere characteristics, make sense to 'go horizontal' at a bit higher altitude. (e.g lets suppose at Kerbin you are at 45° at 10km, the same craft at Laythe will reach that inclination at 15km and pitch down more after that)
  3. Or he may even have some experience with/interest in aircraft but just happens that for this mission he want a rocket. Not everything is about 'efficiency'.
  4. My SSTO is spinning out of control.

    Unfortunately, nothing of this solves your issue. Will you try to move some mass and drag or not?
  5. No, the steereable fins are not a problem. They are just unecessary and ineffective (thus a problem ). One possibility. But there is a few other ways to screw a nice gravity turn, those may be happening too.
  6. My SSTO is spinning out of control.

    That remark always annoys me*. I know that it is correct but the solution is so simple: place the landing gear so the plane is already with the nose a bit up when landed. Really, I don't even remember when was the last time I had a plane that needed pitch to take off. *mildly, but it annoys me.
  7. My SSTO is spinning out of control.

    The point is: the wing is not far behind the CoM. Maybe slight behind, but in no way behind enough to compensate all the drag in the nose. Where is the geometric middle of the craft is irrelevant for aerodynamic stability. You cant/don't want to change the nervs and the main wing? Ok. How about those other engines? How about changing the fuel tanks? If nothing can be changed the 'solution' become more drastic, we need to add things, things your craft don't need and will make it heavier and draggier (IOW: things that make your craft worse. )
  8. My SSTO is spinning out of control.

    Yes. But it may also make things worse. Thing moving in the air want to go heavy part in front, draggy part behing. Your may force the heavy part to stay behing (reaction wheels, RCS, control surfaces) but it become more and more difficult as drag increase. You may use a cannard to try to stop the flpping, but, without adjusting other thing to make the craft more ballanced, it increase the drag in the front even more. So, use it if you want, but move the main wing further behind and some of those heave engines further ahead.
  9. It certainly don't hurt, but that seems to not be the issue there. I build a similar craft and tested it in Kerbin. The main differences are: 1.8t lighter, no fins, Lander can at the bottom, 3xcrew cabin inside a 2,5m fairing (not staged), RCS tank, probecore(okto2) and batteries inside the fairing, 8 unidirectional RCS thrusters for translation only. Launched it (2degree tilt at the launch pad, full throttle, SAS on {craft in aerodynamic unstable, but has a big reaction wheel to keep it pointed where it should}, at 90m/s SAS to prograde), reached a nice 150km x 150km orbit, said hello to my imaginary station and de-orbited. Re-entered pointing retrograde (aerodynamic stable in that position), coming from 150km(pe 9km) I see a lot of heat bars but nothing went over 75% critical temperature, besides the parachute a small 'suicide burn' was necessary to not touchdown too fast. I didn't test in Laythe (honestly, too much trouble just to give advice to someone else) but I don't see reason to believe that it wouldn't be able to do the job there. And, given that Tadpole's craft seem to have similar TWR, deltaV and drag profile, I also expect it to be able to do the job. So, while there is room for improving the design, more probably it's a piloting issue. Now, to lift off from a body with atmosphere you probably want to do a gravity turn. You know it: a small initial inclination and then follow prograde until you get in orbit. The questions are how much tilt and when start the turn. Simple questions, except that 1° or 1s can make a big difference. It depends on the celestial body, but also on the craft, so you need to experiment to find the 'ideal' trajectory for your craft. A steeper trajectory will suffer more gravity losses(more time to reach orbital velocity), a shallower trajectory will suffer more drag losses (more time in atmosphere). BTW: get rid of those steerable fins.At the time you need, it don't work. (that is when you will start the gravity turn, at this point you are at low speed, so low aerodynamic force which is what fins use to steer your craft.) At the time it work, you don't need. (after initiating the turn you want to stay pointed to prograde to minimize drag and cosine losses, the last thing you need is a deployed fin steering you in a different direction). If aerodynamic stability become a issue without it, use fixed winglets(/wing parts) that have better lift/mass. In any case, like others pointed, drag and mass reduction are key factors. pay attention for the opportunities to do so.
  10. SSTO design question

    Not useless but redundant. Anything you can remove and still do you mission without issues should be removed. So, do you need the intake air from pre-coolers? Do you need the fuel form pre-coolers? (Even if you need, that's the best way to havevit?) For what is worth: I like how your craft looks. Not 'nice' but 'functional'.
  11. KSP Age Groups?

    Same for adults.
  12. Seems you already solve the problem. But in a 'brute force' approach, so I suppose you may still be interested in what exactly happened and a reliable way to avoiding it infuture. SO: CoM not in centerline (look at torque values given by KER) Almost certainly the culprit is the payload, try to make it as symmetrical as possible. Don't be ashamed to use the offset tool. Also, if possible, use fairing to avoid asymmetric aeroforces.
  13. KSP Age Groups?

    Sometimes a nice and fun game is just a nice fun game.