Nao

Yup, i pretty much undocked right away, and used all RCS for TMI. Adding a parking orbit of 3,5km and this: ASPLOSIONS! ...way of landing (yep that's 350m/s 3meters of the ground and still sinking), with fuel gone from the spare tanks just as I came to a stop. I thought about just getting CSM to have that 150m/s but then i would have to aerobrake with lunar module which still sounds iffy. (Although i could probably do it in several passes i guess, to not get reentry effects etc ) The main thing is that im procrastinating right now and should be working on my thesis >_< i'ts less than a month to exam and i'm still half way through haha.

@tavert I've build a mockup of his ship in VAB and it looks like 1,4 TWR is with all engines "on" over Tylo. My idea of burning at an high angles came from ascent experiences. For example when you have a craft that has both LV-T30 for ascent/landing and LV-N for interplanetary transfer. During (Kerbin) ascent there was a question of when to shut off LV-T30's and continue only on LV-N's? I've found out that shutting them early and then burning at high angles with LV-N's used the least amounts of fuel. This is also applicable to SSTO's which usually lack thrust if their last stage is LV-N. As for atmosphere less bodies, it's not only Oberth effect that makes low altitude ascents/landings efficient. It's also the the fact that any vertical acceleration gained is (mostly) a wasted fuel. Also timewise if we burn prograde only during ascent, the time to achieve orbital speed increases compared to just horizontal flight, so we get more gravity drag. It's only really visible in low TWR situations thou. For example a test Mun ascent. TWR only 1,21 Launch mass 60,7t orbit mass 55,3t with payload being 49,4t. Only 735m/s Dv spent even thou at first I had to fly with more than 60deg attitude. I would be really surprised if you've found a way to ascent into Mun orbit with payload to launch mass ratio greater than 0,81 (49,4t/60,7t for the example).

Also, there is one more way i try to get to work from time to time (always with catastrophic results ). It could work in theory! With drag model as it is in KSP every ton of fuel/engines will contribute to drag, why not let only wings go fast, and make the heavy fuel slowly ascent through the dense atmosphere.

Yes the LV-N TWR (probably around 0,6 in this case) is too low for whole descent but the idea is to use them alone just for the first part. And then his 1,4 TWR is probably close to the most mass efficient one, it's just hard to fly due to constant need of adjusting attitude to maintain constant altitude. Also about thrust, i think it's a common misconception that big TWR is good for landings/ascents. I did calculations some time ago and the most *mass efficient* TWR for Mun landing was only 1,25 for LV-N engines. For which more than half of the flight was done above 30deg attitude. This mostly because engines themselves in KSP have quite low TWR (compared to their Earth equivalents). Having lower craft TWR means having less engine mass. That is countered by lower fuel efficiency of descent profile, but until TWR's of ~1,4 the additional fuel burned will still weight less than difference in engine mass compared to higher TWR's. (I'm not sure about Tylo optimal TWR thou, i would assume it would be similar to Mun's but i didn't tested it so i might be wrong saying ~1,4 is good.)

Actually no.. i did think of that but until we get limited EVA RCS supplies in pods i consider it a hard cheat . For my mission the lander stage was short 150m/s of Kerbin aerocapture, so i just did that "on foot" (7hr trip), and then spent another 3 hours trying to get to command module. Lastly deorbited with just RCS (which took many orbits as i had Pe of 60km) and used fuel from command module solely for landing. Still i was just curious if it was possible, and orbital trips on EVA are always fun . I don't think there is better way than way you used, while keeping the spirit of the challenge.

Well i tried to be short. And ISP is one element that is easy to see right of the bat in KSP. It would be more appropriate to use exhaust velocity and all that but the effect would be the same. What I'm trying to say is that both ISP and attitude angle can be measures of efficiency if we count work done over just one direction (horizontal here). That is an aerospike engine burning horizontally will add X amount of Dv out of one liter of fuel. At the same time LV-N burning at 61deg angle will also add X amount od Dv out of one liter of fuel to the horizontal direction. So until that 61deg attitude the steering losses used to counter gravity (or should i say gravity losses) are fully countered by higher fuel efficiency of nuclear engines. edit: also the specific impulse is kind of a measurement of speed, as its exhaust velocity divided by earth gravity which is just an constant.

When using LV-N the most mass efficient TWR's for atmosphereless bodies is quite low. I did calculations for Mun and it was as low as 1,25. I think it would be similar for Tylo. So you have quite good craft for it. As you slow down while in Tylo orbit, you need to increase attitude to keep altitude constant. If we compare engines for this task, it turns out that up to attitude of 60deg LV-N's give more energy (speed) just for horizontal slowdown per unit of fuel than aerospikes while working fully horizontal ( 800s ISP * cos60 = 400s , and aerospikes have 390s ). That's why i would advise slowing down only on LV-N, while maintaining constant altitude, up to ~65deg attitude and then engaging aerospikes. Also its best to start from very low orbit (~11km? was it) - just high enough you won't suddenly hit a mountain.

Sooo, is almost 10 hour EVA, with aero-baking a kerbal in the spirit of the challenge ? Because if yes then i have done a direct ascent mission with 534 litres of fuel remaining on ground.

I don't think it's possible, even with a Spaceplane. Aerospike engines have a maximum Dv of around 7600m/s on one stage with payload being only 1% of ship's mass. So even if we take the perfect plane (Dv requirement same with rocket ascent, but with much lower thrust avilable) it's still not enough energy to ascent and accelerate out of Eve's atmosphere. And any other engine has less Dv in atmosphere... Except the PB-ION, although its already extremely hard to to Kerbin SSTO just on electric power. Eve would be even harder. edit: i'm talking mostly stock here, airship mod could help a ton here.

One neat way to go would be to throw the John C. Houbolt's idea of LOR out and do a direct ascent with just the lander. Saving maybe even more than 500 l of fuel It would be reeeeaaallly hard thou.

Just thought of something although it requires at least "default" terrain settings. A Kerbal Nostalgia challenge! Go to KSC2 land there (you can save on ground) and then launch to space! And then return safety to the Kerbin. Bonus points if you go to Minmus and return (it takes less Dv for minmus than mun, and it would be a change in scenery). You can use any engines, wings and docking modules. And you can send as much missions to KSC2 as required - for example to refuel a rocket that went there under its own power. There are many different ways to approach this challenge, it would be nice to compare what you guys think is the best one to use on such mission.

In retrospect, following early development of the game was quite similar to the real apollo program... but done in a "Kerbal" way of jumping on every new shiny parts the engineers produced and pushing the things to a limit. Today with all that F9, Docking, LV-N, timewarp, landing legs and other nonsense it feels different landing on the Mun. Glad i could be part of it, even if i joined forums a little late.

Kerbin! , Nah, it's Kerbol now but i think the naming in the old days was like this: Kerth orbiting around Kerbin, then Kerth became Kerbin and Kerbin became Kerbol. edit: Hey PSJR-112062-300960185RA is my automatic fridge! Dont you dare touching my bee... oh you mean PSJR-112062-300960185RB, ah carry on then!

I'm not sure what equation you have in mind but ... If we consider only one stage there is a limit on how fast we can accelerate with an engine, depending on its ISP. That is, past some point even if we add more and more fuel the Dv increase would be almost zero. The lines on the chart cut at 87,5% because what's left on the ship is fuel tank mass. So if you want to break above 17km/s Dv you would have to shed dead weight (empty fuel tanks) with staging. And still with a lot of stages and fuel taking 99% of launch mass you would get only ~36km/s Dv out of LV-N's.

@Sᴄɪɴᴛɪʟʟᴀᴛá´ÂÊ€ Ah ok agree 100%. More OT: One thing i've started using recently to improve rigidity is to connect *every* part in the central stack to its (stack) neighbor. Mostly with only one short strut. It doesn't provide that much rigidity but blocks any bigger bends on parts that that are prone to it like the small 2m fuel tanks, 2m decouplers or hitchhiker modules. So even under big loads the payload doesn't move too much and it returns to original position much faster. Also about adding struts to asparagus stages, it can work if you: 1)make sure the asparagus stage itself is firmly attached to central tank so even when there is only two boosters left it doens't wobble. 4 struts are usually enough ex: O < asparagus boosters | | <-struts @ <-central stage | | O < asparagus boostersThen use two struts per booster (in the same way) to connect to the payload. This way also you don't need to connect asparagus pairs to each other at all, and it will still not spin during ascent. Cheers!

You can double click on the windows to get closer to them in IVA. I reeaaalllly hope some youtubers start using this, and stop trying to look around from the seat only.

I do agree that the part of the problem here might be a top heaviness of the rocket. But feel like your reasoning for this is flawed. The distance from engine to CoM doesn't influence stability in any way for theoretical fully rigid rocket. It's the bending of parts that make the CoM move off center that's causing the instabilities. And the top heavy rocket creates bigger bending forces. It would probably fly fine if just strutted right. I just wanted to clear that out since i've seen that misconception on this forums several times. (It's hard to judge peoples experience on forums so sorry if you know that already )

This might be useful: Chart is from somebody on this forum but i couldn't find who As you can see only Nuclear engines have the capability to get to 12-15k Dv without staging/refueling.

Uhm, i don't think having a top heavy rocket is bad since it means also that gimbaled engines produce more torque. Its more about the top stage bending around (probably on the 3man pod to lander connection and then more on the big decoupler below). So the CoM drifts to the side. @Op try more struts, especially try making struts between asparagus staged orange tanks and bottom payload, and then another round of struts between bottom payload and rover.

Glad to help There a lot more quirks and shady kerbal physics to add but it's great you managed to get things off the ground, Good Luck!

YaY choco-cupkae, nomnomnomnmom. @Yargnit can you share some of your designs, i would like to try one. @Cupcake... I find signing posts on a gaming forum with own name redundant and overly formal, since we can see your name already... but since it's "cupcake" it makes it hilarious, as if you were addressing somebody cupcake at the end to heat up the conversation. Anyways, thanks for the work you put in creating this challenge... cupcake.

I would advise starting with a simple stock plane and then go with mods. B9 is awesome but it would be easy to overdesign the ship to look awesome just to notice it doesn't fly well. That's why getting around basics in mostly stock parts would be nice. Some tips: Center of Mass should be just in front of the Center of Lift. The more CoM is in front of CoL the more stable the plane will be but more nose heavy requiring stronger elevator controls. I usually put CoL inside CoM sphere. Thrust should be mostly in line with CoM like in rockets, KSP jest engines are very strong getting them not aligned with CoM will make flying hard. For CoL its not really that important to be on the CoM-thrust line but i wouldn't advise placing it too high or low. You can check how the plane will handle in SPH by taking the whole plane and [shift] rotating it several degrees while having CoM and CoL visible. If the CoL does not drift before CoM, the plane should be stable. Watch out for massless parts and other mass changes, they can upset the balance. Namely the "small gear bay" part has no mass in flight but has mass in SPH so set the balance before placing the wheels on the plane. It's good practice to have fuel tanks close to CoM too. Due to how control surfaces have more lift at high Angles of Attack, its good to place them behind CoM so that the plane is stable at high AoA. One more thing about stability is intakes. Radial intakes can generate a lot of drag, so if placed off center or with no symmetry (ie at top for example) can make the ship unstable at higher speeds. One lats thing is Gear. to properly liftoff you can either have main gear close to CoM so that its possible for control surfaces to rotate the plane on the runway, or just make front wheels higher so the plane has natural nose up on runway. Cheers!

You can place BZ-52 radial attachment points in a symmetry below the 2m tank and attach engines to it. You could try searching for "engine clusters" to get some examples.

First time I flew a working jet based VTOL since the jet engines were introduced patch ( around 0.14? ) lol Damn its hard to control them, if i could i would drain all the fuel and flew it just on rockets, it would be much easier ... Proper RCS would help a ton too. Oh well at least i made it. After about an hour of tries and flying around i brought up fraps. And on the 3rd recorded attempt made it work somehow. Also dropped it on the first try too . Also HOMAK! (hands on mouse and keyboard) Video: http://youtu.be/1sGycpJUmjY (hopefully it will be available soon). Didn't had time to mix some music into it, but at least i got better encoding program (Avidemux, so it doesn't as horrible as last time (regatta challenge)) Still abysmal upload speed i got makes it really hard to upload even 480p videos so sorry for bad quality Important time stamps: 2:30 docking, 6:45 drop Driving was a little cheat-y but the pain of landing on the decoupler and the slipping away after 10s on every successful approach made me lazy.

Maybe open the craft file, copy all the contents, and paste it into http://pastebin.com/ it has 512kb max file size so it should be ok. Im getting more and more curious about that phantom coupola