NikkyD

@ snark, i kinda know the standard procedure, question is more: what if i have a rather high AP, should i coast and do the usual or can i somehow profit from it or even turn PE into KE, sacrifice AP for PE.

Help me out here, i am playing around with http://forum.kerbalspaceprogram.com/threads/123114-Single-Turbojet-SSTO-Spaceplane and some question popped into my head. because of the design and other limitations i end up with a trajectory that has an AP of 100km. When my jets top out its at 25km with about 1400 velocity. Now some things are puzzling me. The orbital speed is given as 1400 at 25km and as i get to the AP, which is about 2 to 3 min away it slows down to below 1100. This is not due to drag but because i am exchanging E_kin with E_pot (its what i am thinking, plz correct me if i am wrong). Now if i want to follow oberth, i should thrust prograde asap at about 35 km when the drag is almost zero. However prograde now is about 20° up and if i thrust there, my AP rises and wastes energy. If i aim down at -20° i can lower the AP and move it a bit away from me, buying me time with low TWR engines. But then i am about 40° off prograde making oberth less effective. If i wait until about 1 min from AP and then do my about 2 min thrust it would be the standard but my AP will stay at 100km and for the challenge i only need 70. The initial 100km AP is a given, so lets assume i can't do anything against that, only maneuvers after 25km are possible and the deltaV budget ofc is tight. I know the theory about all the stuff... but i am lost right now and don't know where to start.

What has the whole historic realism thing to do with the kerbal game balancing ?! Once you install the realism mods you have the real stuff anyway.

I am talking about the air speed. Just build a simple rapier + fuel + ram intake and fly it. Only with the good nose cone can i get that fast, ram intakes blow up.

I have a question about the 50% winner... He has 850 m/s on the upper stage, that would require him to make 1600 or more speed (horizontal) with the lower stage which is something that i havent seen any jet engine do yet. The mark is usually 1400 and then you switch to closed cycle or stage. Antbins version looks more realistic but its 45%

If i fly the same trajectory with max payload, i need about 40u of liquid fuel and can get about 4t up to 70+ AP with about 1300 dV remaining. Lets consider a booster being a turbojet with ramintake and a flt100 with only 45 units of liq, thats 2.1t per booster to lift 4t of 2nd stage. with a 909 on the 4t about 1.26t would need to be fuel, with the usual 1/9 tank weight that would be 1.42t for fuel and tank and ofc 0.5t for the 909. So total 1.92t of 4t for the 2nd stage. Neglecting command and steering stuff we have a total of 2.1t booster + 1.92t 2nd stage + 2.08 payload. Thats 34%. Considering i didnt really try hard lets assume 4.5t per booster is possible and the 909 was something with 24 TWR like the rhino we had somewhere 42% With 1 "booster" it will never be much more but if you can compensate CnC losses with bigger combos the 50% is not that impossible as others have proven

It has nothing to do with command stuff but... all mk2 parts have 45 m/s crash tolerance, ALL, even the long cargo bay... just the crew cabin does not! It has 6 m/s. QA at its finest.

At first i had a okto directly under the air intake. It did heat up a lot. Then i switched the tanks around and sandwhiched it, suddenly the intake could take a lot more heat. Same old story as it always has been, a tank can eat up a lot of heat and thus keep the intake cooler. With the shock cone, it weighs more and my tests didnt show any real difference. I don't know why they changed it. Ram Intake can take more heat, weighs less and has more air than a shock cone. The special drag cube of the shock cone MAY benefit you when building bigger craft but i guess the heat-issue will far outweigh that. Another trick, to save energy. When coasting, a lot of minimalistic designs run out of energy and you have to use batteries. You can simple disable the energy on the command unit and when you have to make a maneuver, turn it back on. With long spaceflights (in career before solar) it works with mun stuff if you have no batteries. Update, more testing The remote control unit seems to really be wider than 1.25m, it is visually. It has lots of drag. Drag values at mach 3, when going straight up (reached between 7k and 9k depending on overall drag) and "A.Cd" value in [] shortly after start with 1.0 vector - remote control ~26 [0.17] - Ram Intake ~72 [0.47] - Shock Cone ~48 [0.20] - Turbo Jet ~43 [0.49] - FLT200 ~2 [0.04] - FLT100 ~1.2 [0.03] - FLT400 ~2.9 [0.07] - radial Engine ~5.25 [0.04] If i create a "thinner" part in the rocket, an okto with stabilizer as mentioned before, that part receives less drag but the part below it receives increased drag! A tank below an okto would receive crazy drag like the intake!!! Shock Cone looks superior but the flight is long and drag only matters within the first few seconds. However, the lower my drag the higher my initial AP, so more time for circ and more E_pot. Update 2 I am down to 3927 kg and i am hitting the KSP barrier big time, just look at the screenies. I need something like a FLT50 with only liquid fuel. There is some margin that i found. If i build unaerodynamic stuff, it costs me more liquid fuel as i accelerate slower and thus the jet runs for longer. However i always make it to 80+ km AP because the turbo simple has way too much thrust for that small thing. So aerodynamic flaws are acceptable, overall weight matters!!! But there is no tank that fits my requirements :/ Update 3 With plugin "modular tanks" i am down to 3728 kg. The FLT100 is only used to 80%, 1/3 oxi 2/3 liq. The mod isn't giving me any discount on the empty 20% so drymass remains but i can drop the other tank and thus one drymass less. < 3700 possible, better ascent, closest orbit ever etc

Shark Mk1 Below 4 tons is possible because with this setup it reaches 150 km orbit and i didnt really tweak the ascent angle, lots of space there with the heat. - reason for the 100 kg remote unit: a 40 kg OKTO has no torque and in space you need the torque to turn at the AP and the gimbal of the engines is not really suited for it although it might be possible with lots of patience etc 40 kg okto + 50 kg reaction wheel are both not really streamlined and the remote unit has 15 elec instead of just 5 of the okto. I use a 100 kg Remote + 5 kg solar panel, possible is 40 kg okto, 50kg reaction wheel, 5 kg solar which nets in 95 kg. 10 kg won... but less stable i guess (Okto also has very low temp tolerance). If you change 1 FLT200 tank for 2x FLT 100 (because of the smaller units in which you can lower the fuel) you can drop 5 units of L+O for 50 kg or even drop 10 each for 100kg total. As seen in my screeny nr 3 i have about 10 units left at a 80/90 orbit. So if you manage a 70/70 orbit... 105 kg less would be possible but the way i built it even a bloody beginner can fly it. Full Throttle all the way, once you lift off with the use of SAS aim for 50° angle and just hold. Once the engine tops out at 22km turn SAS prograde to minimize the mini drag losses (might still cost you 2km orbit or so). About 1 min before you hit the AP switch engines and burn at 0° angle, will have to burn 2 min. Some minor adjustments for circ-orbit will be necessary but thats it.

I like the idea of having the option to use a really light weight can that has 0 protection and a heavier version with heatshield/aero (capsule). The parts are already there, but they are simply not balanced, never were except for the two 1.25m ones. I don't care so much about historic ones, that could be added via mods to not clutter the stock game because mainly the stock game needs parts that allow building rockets after the same principle, like the fuel tanks. All except the oscar b tank have the same 1/9 dry mass ratio. With 1/4, 1/2 and 1 size fractions they allow more freedom than there are suitable engines or command pods.

What we need is quite simple, scaleable SRBs for every diameter. If i want 2.5m boosters, give me one, if i want it to have 100t of fuel, it should as a consequence have to be 50m tall etc. Then let me select a burn profile, like 100% thrust for the first 10 sec burntime, then linear down to 50% for 10 sec burntime etc. And ALL you really need are 3 SRBs, or SRB hulls and everyone can build the booster they want/need/require for their mission.

i knew "there is a mod for this"

Where can i find data on where duna needs to be for that maneuver to work ?

Landing gives extra xp and that's finding excuses why "all is good" when it isn't.

Its simple values in a cfg file that MATTER a lot. So how hard is it to have one dev sit down and go over it for one hour ?! They have tweaked other things, so they had time for that but no one ever bothered with the pods.

I WOULD put foldable wings on that sucker and put it in a fairing alltogether... and im pretty sure "there is a mod for that" The design wasnt by choice

I was already planing on a mun slingshot again, thats why "all" and in theory mun or minmus COULD be in the way when Duna is in the right spot

So for the 130 m/s to apply i need the right constellation of ALL involved planets/moons ?

The design is far from perfect as i have been trying to stabilize it this way. I didnt expect the wings to cause ANY sidelift at all as i didnt plan for any deviation from 90° below 25 km

Can someone explain to me how to make the 130 m/s from just leaving kerbin SOI to Duna intercept ??? The rest should be aerobrakeable. MJs hohmann says 850 m/s to reach Dunas orbit

@slashy, the idea was to drop only the orange tanks when out of the atmosphere and so on. The 2 long 1.25m tanks are supposed to circ the orbit and reach kerbin SOI. Plane has 2 909s and i wanted to use them for as many things as possible so i stacked tanks.

That's afaik the wrong thinking cpt hunt. Especially with a cmdpod size and shape, weight and loadout are all important factors. LanderCan size and shape is different and may matter to the guy designing his rocket

Fair enough, now i have to figure out where to get the extra dV as the budget was already tight and those wings are not for free :/

I'm pretty sure this will cause rapid disassembly

best "Container" is the mk2 crew cabin with 2 tons for 4 seats -> 0.5 t / kerbal ofc its a mk2 part and has trouble fitting normal rockets...