Spricigo

For the sake of comparison 2xPoodle VS 3xDart VS 9xTerrier: P: 2600funds; 3,5t; 500kN; 350s; 4,5°; Alternator. D:11550funds; 3t; 540kN;340s;no gimbal; no Alternator. T:3510funds;4,5t; 540kN ; 345s; 4°, no Alternator IMHO 3% difference in Isp is negligible, thrust about the same, gimbal/alternator not much relevant. If not the case of milking just a ditch more deltaV, is a choice among size, cost or part count.

Kinda question to answer with a "for what?" OK, you said it's a interplanetary craft and you are concerned about fuel consumption. However it depends on some factors, some concerns may be burn time, if the engine can also be used for landing at some celestial body, cost, size, total craft mass among others. But in the end it mostly boil down to what the rocket equation says (link below to an online calculator ). And, to a considerable lesser extent, to your TWR (mostly for convenience) The rocket equation determine how much deltaV you will have based on: some constants, your Isp and your wet/dry mass ratio. Everything being equal you want the engine with higher ISP but since different engines have different mass sometimes an engine with lower Isp can be better because is much lighter (e. g. For a satellite under 500kg with 1-2 Oscar-B tank worth of fuel nothing beats the Ant, not even close) The better idea it's to find out how much deltaV is needed for the mission and run the numbers. Just remember: 1) a vessel should be designed in the reverse order of use. 2) what you don't need/can go without, it's often too heavy to carry. http://www.quantumg.net/rocketeq.html

I didn't flight enough to know if more TWR is needed. Close to 2 is not rare in my LV, but that's for convenience instead of efficiency.

Inb4 an option to simulation the vision problems because long time in space.

The 3 more common causes of failure to design a spaceplane are (in no particular order) : >too much weight in the rear >too much drag in the front >both Sometimes the flaw is not obvious looking at CoL/CoM indicators in SPH since the problem only appear in a different situation (e. G craft with different AoA, drag caused by vertical surfaces, less fuel in the tanks) still is a case of CoM behind CoD. The specific case is craft dependent, so screenshots or craft files are required to give better advice. Another point: it may be a piloting issue. Or even the 'less than optimal' controls we need to deal with in KSP. It's worth to try with stock/shared planes just to be sure.

The deltaV requirement for inversion of orbit will be twice your orbital velocity at the maneuver node. Certainly gravity assists may help alleviate the cost, but a single flyby around Duna is out of question for sure. Jool can help more since is farther away from Kerbol (lower orbital velocity) and is more massive. But reaching Jool has its own cost.

Probably caused by misalignment of RCS thruster, worsened because the vessel its so compact and light. A translation Input causes a rotation and SAS try to compensate for it with the opposite torque and just go crazy. The simple solution its to set RCS to only respond to translation inputs and let the rotation be handled by Reaction Wheels. In settings turn on "advanced tweakables" Right click on RCS thrusters, [show activation toggles] turn it off for Pitch, Yaw and Roll

Actually there is several aircraft autopilots out there:

Not in stock. There is a few mod option if you want to circumvent the whole clicking for science altogether. Examples:

After reading the instruction I tried 2-3 launch each. They are easy to control, but I tend do have a bit more TWR in my LV (specialy 1st stage) and launch it in a Fire&Forget manner. I suspect that is why I had some problem to follow the flight profile. More often I had no time to leave the atmosphere in time to switch to the lower stage for recovery but in other attempts I screwed the orbit. I guess with further attempts I may learn to do it right, but given my play style I don’t have the urge to. For now I'm accepting that my flight skill is a bit too low. Also, considering that I use FMRS, I'd rather design the lower stages to provide some glide control to try to come even closer to KSC but for a pure stock system this is counterproductive because of the increased time for the lower stage to touch down.

I download it read the instruction and tried to use it. So far I have to say it requires some skill I seem to lack. Each time I either failed to recover the first stage before it vanished or to reach orbit (and once I managed to fail in both ) Was an intersting experice but I have no qualms about FMRS and normal difficult, so Im going back to my Fire&Forget Expendable LV. Maybe I try it again later.

@StahnAileron interesting your reference to Gravity Turn as 'learning tool'. Myself, I design my rockets to launch then in "fire and foeget" mode and use GT as benchmark for evaluation of the effectiveness.

There is a few reasons, among it: > More powerful engines are also heavier, so your dry mass is higher, so you need more propellant to get the same deltaV >A high thrust engine can change the velocity quickly but also run out of fuel quickly. How high is your thrust have the same importance as how quickly you use the fuel for your deltaV budget. >Too high thrust may cause drag and control issues resulting in less theorycal deltaV turning into effective deltaV.

If that was in flight the readout was porbably the remaining deltaV, also its possible that was in atmospheric mode (a estimative of the effective deltaV taking in account drag/gravity loss). Also, as @StahnAileron pointed, KER sometimes gives inaccurate number depending on circumstances.

Well, I think we need to agreed that we disagree then. Just to present my reasoning: 1st: elegance is overated, we dont need much of the luxuries KSP offer us, is a proven fact 2nd: no problem with a elegant glide back to the runaways or a well performed suicide burn back to launchpad. But letting it fall and open the parachutes just a couple of hundreds meter above KSC also have its value. 3rd: My divergence is mostly because aerogav was suggesting for a rocket only(or rocket focused) career.

Its not my fault so much of the important rocket science was done by Germans and Russians. Thanks for the correction.

lets ignore the atmosphere and suppose that we can apply ridiculous amount of deltaV instantly Orbiting Kerbin 'at ground level' would requires a velocity ~2400m/s , lets consider starting at ~200m/s (Kerbin's rotation) , then we need 150m/s for a hoffman transfer (again with super-dupper-hiper-mega-quantum-relativistic engines and no atmosphere). By my bad maths its 2350m/s even before accounting for the losses caused by gravity, drag and piloting. https://instacalc.com/42836 https://en.wikipedia.org/wiki/Vis-viva_equation http://wiki.kerbalspaceprogram.com/wiki/Kerbin

I strongly disagree. Design your re-entry vehicle to be stable and follow a good ballistic trajectory instead of counting on control surfaces to steer it. IMHO is a good practice, better to adopt it sooner than later. Also we have 'magical reaction wheels' and different tech nodes provide Basic Fins, AV-T1 winglet, service bays* and AV-R8 winglet, so aviation is not even required for steering. *a.k.a MK0 airbrake.

^this Notice you can just pick the contracts you like and let the others expire. You will only receive a penalty if you decline (small reputation hit) or if you fail after accepting it. If I'm planing a mission to landing a kerbal in Eve and return, a contract to conduct temperature reading at surface of Kerbin is asking to be ignored anyway.

QFT. Even then quickly become less useful once you have access to Nerv and RAPIER. So far I think you made the case for recoverable rockets. Have you considered TSTO spaceplanes/air launch to orbit, using drop tanks with stage recovery or using FMRS? Actually is not that different than relearning to flight a slight different spaceplane while is true that initial condition make much more difference for gravity turn. What I do its to design my launch vehicles to lift a standard payload mass/size, and try to design my payloads with that size/mass. Often a smaller payload can be used for the 'rounding'. e.g adding a half ton satellite to a 4t payload to get closer to the 5t the LV is designed for. Another point its that slight differences in a rocket usually just requires slight differences in the initial angle/thrust or how long until you adjust SAS setting.* It may seem complex but once you get used its not difficult to judge which adjustment is needed. Anyway, I think that its enough out of topic. Maybe we can discuss it in another thread. *disclaimer: A) I design my LV so my launch procedure is 1.launch 2. set SAS to prograde(or turn off) at a given speed or height 3.circularize at apoapsis. Maybe use the WASD keys when circularizing (doing it less and less often) but not before. Staging is handled by smart parts. B) playing in normal setting (which is what I do) allows for less than optimal LV cost wise, a few extra funds for some convenience is a fair price. In particular SRBs in first stage may be(and often are) tuned for better control at cost of efficiency. C) Like spaceplanes, rockets also have flight profiles. "reach 45° at 10 Km" is a common rule of thumb (but don't fit every single rocket out there). Also like spaceplanes abrupt change of directions are usually counterproductive. If you are fighting the rocket something is wrong.

I For the formulas to calculate range and signal strength look at http://wiki.kerbalspaceprogram.com/wiki/CommNet Notice that a link of any strength provide full control for unmanned vessels.

Yes, this design probably just need to drop periapsis into atmosphere and maintain retrograde. Nonetheless I often had a overfueled ship in a slight higher orbit. Rather than wonder if it would make any difference, I just lowered the orbit. It may not have mechanical effect but cause a psychological effect.

While Lelitu is correct, a word of advice about shallow trajectories: Depending on you craft you may end in a layer of the atmosphere hot enough to increase the temperature but not dense enough to slow down the vessel. In this case the solution may be to dive deeper into atmosphere to slow down faster and give less time to heat up.

I didn't tested it myself but I suppose it can handle the heat. In my experience coming from low orbit (70-100km) it's enough to lower the periapsis to 10-15km. If you have enough fuel and electricity may be worth to lower you orbit to something like 75 x 75 before re-entering.

Well, IMHO engines that never get used are deadweight, monopropelant and reaction wheels that get used is not.