NikkyD

There are some things that you don't consider. The 909 is so short that you need less fairings which means less weight, the LVN is really long and require larger fairings and thus more weight.

@godefroi, if you drop the stupid winglets you can get this thing into orbit, at least i can. I dont know how to express everything here in text so i just note some pointers: - with realistic drag your rocket should always be prograde, never have the chevron at the border of the yellow circle but always inside centered if possible. - turn on debug drag info in action menus, right click your nosecone, the drag vector should always be 0 / -1 / 0, if it turns to -0.1/-0.9/0 you are in danger of tipping over - once you lean your rocket over to the side (start a turn) your rocket will fall by itself depending on its weight, speed and TWR. -- too fast and you wont fall much, too slow and you fall over (flipping) - drag increases like crazy when faster than mach 0.8, keep an eye out for the drag number, if it goes up like crazy, you are too fast - winglets CAUSE DRAG! Using winglets to enforce a trajectory means you do not understand how your rocket should ascend ! Unfortunately you can no longer rely on MJ to do a good ascend for you with some rockets

I just wanna add to this thread. Terminal Velocity means the gravitational force equals the drag (force). The heavier your craft the higher its TV. Some crafts will be so heavy that their TV is above mach 1 at which you have increased drag.

Elephant in the room ? KSP has way too heavy engines. So the whole SRB thing is not really touching me. Real boosters have burn profiles, would be nice in KSP. Quick 10 sec max boost for the start, slow drift the first kilometers with increasing force as the atmosphere gets thinner. But still, using booster over engines is not the real issue. A lot of the balancing sucks tbh.

I suggest the following rocket for "very small" testing category: OKTO2 control, the very small aerodynamic nosecone on top, 3 Oscar B fueltanks and one 48-7S Spark engine. If you use mechjeb, put it on top of the okto before you place the nosecone, if you attach it to the side it creates drag. This rocket has a very good budget and doesnt allow crazy maneuvers.

If you simply put 2 SRBs left and right without nosecones the additional drag WILL cost you. People have been building rockets way too crazy all the time because there was no aerodynamic, now that its here some ppl have a rough awakening

the whole "following prograde" greatly depends on the weight distribution of your rocket. If you have a very long rocket the fuel is used from top to bottom so the weight shifts, you have a heavy head (payload etc) and a heavy rear (engine and fuel left). Some designs just cant turn as quickly as others Edit: we should all use the same design, a simple few parts rocket with the same engine and same dV.

Ofc i let MJ do the ascent, the only way its accurate and reproduceable. Will try your profile tomorrow, getting kinda late for me but i have to say if you have to use winglets afaik something is wrong because a rocket shouldnt have winglets

Are you (all) talking atmo or vac dV, cause i only look at vac

I skipped 1.0 + 1.0.1 but had every one before that and i don't see anywhere under 3.4 without exploits or semi planes and in every version i was trying to find the most efficient ascent, so please... further 1.0.2 tests: - going to 30 and speeding with 0° to reach AP of 80 isnt working well. Still too low, i see hot-atmo effect before 2km/s, fuel runs out - works at 35 but not very efficient - at 35 aiming 10° works better, requires circ.burn of about 400 dV. Reaching AP of 80 at about 40km alt with 2000 km/s, losing up to 100 m/s while coasting - old style, 5/70 @100% (mechjeb) i reach AP too quickly with only 600 m/s orbital, ends in about 3.9k dV best attempt is a 1/35@100% to 5° profile with an accel-limit of about 20. Can speed up more with gimbal engines, might not make it without gimbal depending on design. winglets cause more drag than they are worth. parachute or aero nosecone doesnt make any difference. rocket may flip backwards if very long and fuel empties out from top, so i had to make fuel go back up to keep the nose heavy. Main problem is stability vs speed. - If you go too slow you spend too much time in atmo - If you are REALLY slow the nose might fall to the ground - too fast means course change happens too quickly and drag is pushing the nose down -> spinning I dont see where 500 of 3500 might be saved

Ok, im calling BS on the 3.000 dV to LKO. I guess some control surfaces generate lift because he is turning so extreme and has more of a 90% rocket 10% plane. I just did a lot of profiles and roughly 3500 dV is the figure. I use a really simple design, MK16 parachute on top of a MK1 cockpit without monoprop, service bay to store mechjeb in (just in case, avoid drag), followed by 2x4.5t tanks and one lv30 engine. The engine has 280-300 ISP so my dV estimate atm/vac is roughly the same. This setup gives me 3414/3658 dV and more than 100 dV(vac) left i couldnt pull off. Maybe 100 dV less, maybe 150 but no way 500+. I usually play with the "all realism" mods because stock is very childish but now with fairing and realistic drag i gave it a shot. Terminal Velocity should still be valid, so i don't know why you all are going so slow with 1,5 TWR and doing kamikaze turns. If you do that, you need to find the sweetspot between drag and gravity flipping your rocket over but you will still be within the atmosphere way too long if you finish the turns at 20km. Using winglets to be able to actually fly your maneuvers already shows that something is wrong!

sorry for bringing this old thread up again but... has this been answered anywhere to anyones satisfaction ? What i'm trying to calculate is, when i enter muns SOI with speed v_0 going straight "downwards", with what speed will i hit the surface with (and thus, how much delta_v will it cost me to land)

The game does not calculate lift and drag individually for each part but for the "rocket" as a whole.

There was a challenge like "least deltaV from LKO to mun surface", can't find the thread, can anyone else find it ? Edit: thx @ Yakky, u are right in addition: if maccollo is right with http://forum.kerbalspaceprogram.com/threads/73696-Landing-from-Low-vs-High-Orbit?p=1045038&viewfull=1#post1045038 a perpendicular drop from 2.400.000m with initial velocity 0 would result in an impact velocity of 546 m/s same with initial 500 would result in 650 m/s My thoughts were that if you, in fact, race towards the planet, you spend less time in its gravity well. If above is correct, any attempt to waste fuel on entering muns SOI with lower speeds is counterproductive! So the cheapest way is in fact to reach muns SOI with the least deltaV possible and have high TWR for a good short suicide burn. comments welcome !!! Edit #2: somehow the math of maccollo seems off, the interesting part remains. Just performed an almost complete stop at the corner of mun SOI and would have impacted with 770 m/s (roughly didnt watch) the same without any correction (vertical speed, mechjeb, -350 m/s) results in 850 m/s impact!

Similar question bothers me lately and quite honestly the answers here are not sufficient. Given any craft with good TWR and the requirement of a really soft landing on the mun, how do i get the most out of the mun gravity ? Let's ignore the part how i start from kerbin. If i go vertically and my AP is exactly in muns orbit, if timed correctly, i would enter muns SOI "standing still" seens from kerbin, but seens from mun i would enter its SOI with 542 m/s straight towards the surface. I would accelerate some more and had to fight all that, doesn't seem smart. Now lets say i do the same but enter the SOI about 45° towards kerbin. There is a chance that the speed is so high that the mun pulls me towards it but flies by too fast. Same if i enter the SOI from 45° "higher". I could time it so that i enter before or after reaching AP and still have some velocity up/down (from kerbin). But being in front of the mun is not helping. If in theory i could be 1 km above muns surface with the above velocities, from muns system it would be like i got ejected with 542 m/s from mun and gravity would slow me down and i would fall from a certain altitude and only had to brake that down. I am playing with windows paint trying to figure out if there is a way that i enter the muns SOI in such a way, that it wouldnt require me to do something wasteful before and so that i can use its gravity for maximum deacceleration, but i just cant figure out whats more beneficial. In addition, if going bi-elliptic, i could enter the muns SOI from low and behind. My orbital speed would mean i dont need to brake down the full mun orbital speed and if the AP (from kerbin) is close to the muns surface i wouldn't have to fight much gravity... but the fact that no one pulled this off by now somehow makes me think its impossible and i am missing something! Help me out here

Bender, you have a completely different rocket. Ariane 5 ES has a very powerful first stage, with about 3,3 km/s delta and TWR somewhere 1.7 (mechjeb only shows full vac values). 2nd state (main stage without boosters) continues with about 4,5 km/s and 0.8 TWR upper stage then has 1,3 km/s with 0.2 TWR and the original engine isnt in my parts so i have to use one that has twice the thrust, but at that stage i can accept that. I am flying the ATV mission with the record payload of 20 ton to 260 orbit. Just found some footage of the real start and ascent and ... somehow i cant really figure out how exactly they do it but i am pretty sure they pitch up like badass after the AP, like i do. They only go to 135 km AP and drop back to 125 ish within a couple of minutes, they HAVE to thrust upward. When they reach 7,1 km/s orbital, they separate and now the last stage with its 10% TWR somehow climbs up from 125 to 260, coasts and then circs ... i just dont find ANY explanation as to WHY they do it this way

Ok i achieve orbit now but it seems very inefficient, but that may just be the conversion from Kerbal Fantasy Rockets to REALITY. Mechjeb seems to always show the TWR with max thrust but thrust should be dependend on atmospheric pressure so i simply assume my values are like the real Ariane 5's because it matches it very closely. - I start vertically until i leave the launch clamps - now i roll so that i can steer more comfy and pitch about 15°. Because i have to do it manually the rocket wobbles a bit when the SAS is trying to stabilize after each key-press - the nose tip now falls over slighty, which is ok, i steer right after it, so my direction is just at the back-end of the yellow circle - when i come close to 45° i wait until my AP is estimated somewhere 180 km - then i go completely horizontal with some seconds of booster power left - at about 100km altitude my booster run out and i eject them and the fairings which make about 1,5% of the weight at that point. - now i have 2 minutes to AP and i am thrusting with about 8 m/s^2 and TWR 0.8 - within those 2 minutes i manage to get from about 2 km/s orbital to 2,3 km/s NOW comes the wacky part - at the AP i have to pitch up about 30° to reduce the dropping to about 50 m/s - as i get slower the vertical speed reduces and i reduce the pitch accordingly - from 30° at 2,5 km/s i go down to 5° at the end with somewhere (sorry forgot) 5.5 to 7 km/s - now i eject the main stage with still negative PE and my upper stage fires with TWR of 0.2 and about 1100 deltaV - upper stage has to pitch up to 10° again to not fall - after minutes i reach orbit somewhere 200 km and still 600 deltaV left (i admit, i already reduced the initial upper stage fuel by 20%, else i had 1000 deltaV left, enough for 2 MM orbit - so depending on the fuel i put into the upper stage i can get my dummy container of 20 tons of water into a orbit as high as 2 MM BUT there are some questions that pop up whats the point of using so much fuel in the main stage with such low TWR ? I am fighting gravity like a maniac, pitching 20° or more for several minutes. More powerful engine would reduce the time and thus save so much fuel ?! the original ariane profile shows that at the upper stage separation it now points upward and "injects" the upper stage into the destined orbit. What was/is the point of circularizing at 150 to 180 km if you plan to go higher anyway ?

How much RAM does it use ? I use the medium textures and the game needs about 3.3 GB

I personally dont have a problem with circ. after AP, but i would need about 4 minutes and after 2 minutes i am already going down like a rock. Some numbers, i go up with about 20° from FR kurou. After 2:20 boosters are out and i have (depending on angle) an estimated AP of somewhere between 200 to 250 in about 2 minutes. I drop the boosters and go completely horizontal. I have about 2km/s now (orbital). TWR is 0.7ish, accel is 5 m/s^2. When i reach AP i have a couple 100 m/s more. Now because my speed didnt increase that much, i am going down as i went up, so i have about 2 minutes to push my trajectory but with the slow TWR etc 2 min after AP i am at maybe 5000 m/s but my trajectory is going down. At this point i am dropping below 150 km (depending on AP) and i have no chance of ever establishing an orbit. Main question is: where should the rocket point ? The fligh paths are clear, but how do i reach them ? Should i circ. pointing horizontally or some degrees up ? etc

For the last days i've been trying to get ascents right with the realism overhaul, but mechjeb just wasnt made for it and i dont find any other tools that would do an automated flight like mechjeb. Now i built myself a somewhat realistic Ariane 5 and gave it a 20 t dummy payload. Following this http://www.spaceflight101.com/ariane-5-va210-mission-updates.html . I just have NO idea how to recreate the angle at which the real ariane starts. I tried some stuff in mechjeb but after the booster separation my flight data is more and more off. The main stage seems to have only a TWR of .67 and i hit the AP way too early. It should take about 5 minutes to get up to orbital speeds but when i am half way through, i am already dropping down again. Can anyone give me some pointers ?! (stock game + FAR, i can achieve really great efficient orbits)

No need for long discussion, i just didnt know what you guys meant by airhogging. 3 or 4 ram intakes are the best ratio per turbofan from my calculations.

that is inaccurate, intake air also depends on velocity. And how did u calc the green line ?

What exactly do you all call "airhogging" ?

I dont share that opinion. It just allows ppl to adjust the payload by 100 kg if they are short on Delta-V. Its more convenient than having an exact payload that doesnt move or blink or flinch.

Sorry, it looked like this one mod cockpit that has everything in it, monoprop with rcs, a chute etc