The Single-stage Altitude Challenge

[Atanar]

I must have completly overread the "no jets and wings". Where does this thread say it?

Also, is nuclear engine on top of solid booster legit? Explosions are technically not staging...

[lump]

Wow nao, that thing is gigantic, even my biggest kerbol escape SSTO is smaller (i think), and it can't escape kerbol?

on another note, I'm adapting my 5 tonne SSTO/interplanetary lifter so it can be refuels and restocked, truly reusable, will post pics when finished.

[tstehler1]

Also, is nuclear engine on top of solid booster legit? Explosions are technically not staging...

I suppose that's legit... if you want to risk the explosions, that's your own problem. If it works, then good for you

Sorry I haven't been on here in a while, I'll try to monitor a little more closely.

[lump]

ok, i've stopped adapting my lifter as the part count became too high, which I'm doing now is toying with my super small SSTO by making it easier to fly.

[lump]

People, i have finally made an SSTO with over 3000m/s delta-V once in orbit, on my preliminary tests i got 3200m/s delta-v out of it and i know i can get into orbit with more. I think once i've equipped it i will send it to duna and land before taking off again, right now she's called chomper but if you have any better suggestions please just say.

this is her, at 8000 fuel she isn't my lightest ship but she is a lot smaller that some of my monstrosities

she outperformed my expectations, she is my second favorite SSTO after my super small one

[Nao]

Nice-u lump,

I'm close to beating you thou, as my current ship with pretty bad ascent (almost circularized orbit at 52km) got up to 3114m/s Dv at 78x78km

It has 39parts and needs no fuel or engine managment.

This starts to be close . And it looks like it's more about making an efficient design rather than just moar power.

edit: similar design (4 aerospikes instead of 2 and 2 small boosters) have 3250m/s Dv at 75x75km orbit and finally managed escape yay.

Or you can be judged by your velocity at infinity, which is trivial to create...

Could you elaborate? I have KER on my ship so i can just do the maths, but is there a way to find that velocity for a craft that's without MJ or KER ?

Edited May 7, 2013 by Nao

[lump]

yeah, that's what i like healthy competition, although looking closer our craft seem to be roughly identical in terms of fuel and engines. It seems great minds think alike . Anyway to test "chomper" i sent her to ike and i clearly have enough fuel to get back, i wish macey dean saw us as he wanted a viable SSTO for other planets.

Pics:

^i've stuck with the shallow launch angle as you can see, safety first(i can't say that with a straight face on ksp)

i actually took this picture on a test with parachutes but i use much the same launch angle for all of the good SSTOs

^ managed to get one of the best Duna encounters I've ever had

^areo braked like ten times to get a good ike encounter, luckily ike was in a PERFECT position, literally

^second time i've landed on ike so that was fun

^we have touchdown!

^ this is the glamor shot for all of the kerbin press

I still have over half my fuel left so i should be able to get home, i didn't bring parachutes as every little helps but next time i hope to land and return from Duna, it's funny actually because i think my ship has almost exactly the same amount of delta-V as Nao's, mine had 3200m/s on preliminary tests which i'm sure Nao's SSTO can beet aswell.

NEXT STOP 4000m/s delta-V, we might need to team up for that one though, it aint gonna be easy at around 50 parts(which is what i and by the looks of it Nao aims for, nice and healthy number for all systems )

BTW i think my SSTO has about 47 parts which i could reduce with say, bigger fuel tanks, less struts and less octagonal struts.

Edited May 7, 2013 by lump

[Nao]

^i've stuck with the shallow launch angle as you can see, safety first(i can't say that with a straight face on ksp)

i actually took this picture on a test with parachutes but i use much the same launch angle for all of the good SSTOs

^second time i've landed on ike so that was fun

NEXT STOP 4000m/s delta-V, we might need to team up for that one though, it aint gonna be easy at around 50 parts(which is what i and by the looks of it Nao aims for, nice and healthy number for all systems )

That's shallow? Looks too step for my tastes . I try to get 300m/s at around 65-60deg attitude.

@Landing on ike. Now go find the boulder!

4000m/s will be very hard to do. I think even impossible without wings, jet or ion engines. As the mass of our cargo is already only several percent of the total dry mass, that means even if we use several times more engines and fuel tanks, the outcome will not change much.

It's more about how much performance we can get out of current engines. Keeping the TWR as low as possible while still flying optimal ascent path and using engines 100% constantly.

[lump]

yeah, even changes with likes of a tonne can render my smallest SSTOs useless, i agree with your points entirely, how i usually get a SSTO to function better though is essentially make flying fuel tanks, if my SSTO can lift, say 6 extra tonnes i put 2 extra fuel tanks at 36 combined tonnes with an engine to lift their weight, essentially flying fuel tanks, i also find fuel lines to be useless unless you're pumping fuel to a more efficient engine.

the reason my SSTO can go closer to 45 degrees in the launch angle is because it has 5 nuclear engines, on this version it was worth the extra weight as i could start much earlier, I've learnt a lot in rocket building since starting to build SSTOs, it's so great when a SSTO design works

[tavert]

Could you elaborate? I have KER on my ship so i can just do the maths, but is there a way to find that velocity for a craft that's without MJ or KER ?

Only need altitude and speed for this. That and what you're orbiting, so you know mu and the radius of the body.

v_inf = sqrt(v^2 - v_esc^2), where v_esc^2 = 2*mu/r.

[lump]

double post

Edited May 9, 2013 by lump

[lump]

ok guys, i have halved the fuel in my 3000 m/s SSTO from using a rule (that i might make a thread about due to it's potency) that can create some awesome SSTOs. I actually made some smaller ones than her but was having a problem that meant i lost between 500 and 1000 m/s of my final speed and so even though my calculations said it should have 3000m/s delta-Vin orbit easily no matter what i tried i could not match that, i eventually decided to go round for another pass after burning roughly 800m/s up to a minmus orbit as i knew this can help slow ships, well boy did it help, i got all the way up to the 3100m/s delta-V mark.

Pics:

on this test i was checking the fuel every 200 to sea if i was on track, at this point it was evident i was gonna make it

this is quite a bad shot of the rocket but you can get a rough outline of what it looks like

breaching the 5000m/s mark

my final velocity was 5100m/s

bye bye kerbin

Your move Nao

[tavert]

Very nice lump, told you SRB's are useful. You should put landing gear and parachutes on that bad boy and try a Mun round trip. I'll have to re-evaluate aerospikes on my designs... I had refined things to 4500 liquid fuel, 3 T30's, 2 LV-N's, and 4 SRB's, aerospikes might cut enough fuel off that to be worth the extra quarter ton of engine mass.

[lump]

they were pretty useful as of now but i think i can do it without them tomorrow as i only added them while my equation problem was happening, now i understand my ships were working i can get smaller and better designs, but i may do a mun trip, maybe.

about the areospikes i usually get no actual agin from them other than a reduce in the used fuel which is pretty good but is usuallynot worth the instability of them.

[Nao]

Only need altitude and speed for this. That and what you're orbiting, so you know mu and the radius of the body.

v_inf = sqrt(v^2 - v_esc^2), where v_esc^2 = 2*mu/r.

But isn't the burnout speed needed in the equation only valid if measured at Pe ? That's my problem, if i have a ship in space in KSP that already passed Pe, without mods i don't think i can see what would be my speed at Pe unless i had more information like longitude of the ascending node (not sure if this is correct term even ).

We could of course escape from Kerbin at such angle that make us pass Kerbol Pe right after exiting Kerbin SOI but that's hard sometimes, especially with super low TWR.

@ lump,

Wo ho 5km/s thats great! Challenge accepted but i really doubt i can beat that X_x

[tavert]

I think once you're out of fuel your hyperbolic trajectory will maintain a constant v_inf, since v_inf^2 equals twice the specific orbital energy. The periapsis speed is different from v_inf. If you want to calculate periapsis speed then you first have to solve vis-viva for SMA: v^2 = mu*(2/r - 1/SMA), so SMA = 1 / (2/r - v^2/mu). Then plug in periapsis plus radius of the body for r to get v_peri.

[Nao]

I think once you're out of fuel your hyperbolic trajectory will maintain a constant v_inf, since v_inf^2 equals twice the specific orbital energy. The periapsis speed is different from v_inf. If you want to calculate periapsis speed then you first have to solve vis-viva for SMA: v^2 = mu*(2/r - 1/SMA), so SMA = 1 / (2/r - v^2/mu). Then plug in periapsis plus radius of the body for r to get v_peri.

Ahh thanks, that explains it nicely!

As for my latest progres: 3341m/s Dv at 69,5x69,5km. All in one burn up to circular orbit just above atmosphere lol.

I've ran into escape trajectory bug again so i think ill need to fly the mission again on another save. It basically brings FPS to singe digit sometimes when there is a ship on escape trajectory out of the system. So i'll edit the results later.

Edit:Through the lag i made quite inefficient escape (30 deg off ' ) and using the above mentioned formula got v_inf at 1520,8 m/s.

Can you cont yours v_inf lump ?

Edited May 10, 2013 by Nao

[Lexyz72]

Hi guys. I just created a small rocket in 10 mins wich on first try reached (i didn't write down the numbers but on map its around 3 or 4 times the distance from Kerbin to Mun), but after adding more fuel for second try, I was able to escape Kerbin's gravity and am now in orbit around Sun travelling 10.5 Km/s. It has 7 liquid fuel engines (middle +6). Engines are LV-T30 each supplied with 3 largest fuel tanks for their size. The SSTO has 38 parts and fullfills all of the requirements for challenge.

[lump]

Nao, when i said 5100m/s that was final velocity at engine cut off not delta-V, my delta-V was 3100m/s and with 4000L of fuel it's pretty dam good

( especially when i see your giant orange rocket achieve much the same). I am racking my brains trying to remember the rocket i built with 4000m/s that i scrapped due to one bad run.

i've looked at tavarts equation and i understand mostly what to enter but what is is actually for, i do not usually use many equations, just one for efficiency which i compare on a graph to get delta-V and a few others to get expected fuel needed for the rest of the burn compared to the fuel i have.

[Nao]

Nao, when i said 5100m/s that was final velocity at engine cut off not delta-V, my delta-V was 3100m/s and with 4000L of fuel it's pretty dam good

( especially when i see your giant orange rocket achieve much the same). I am racking my brains trying to remember the rocket i built with 4000m/s that i scrapped due to one bad run.

i've looked at tavarts equation and i understand mostly what to enter but what is is actually for, i do not usually use many equations, just one for efficiency which i compare on a graph to get delta-V and a few others to get expected fuel needed for the rest of the burn compared to the fuel i have.

Tavert's equation solves v_inf - its the speed the rocket would have after infinite amount of time passed. I think it's called hyperbolic excess velocity. Its just a measure of how much speed (energy) above escape velocity we are carrying. Very similar to the maximum altitude for elliptic orbits.

I think it's the best way to compare our results. (Unless we agree on using KER or something and just use the (negative) Ap value).

edit: actually i'm ok just comparing Dv at 70-100km orbit as the escape burn is long and can get tricky with low TWR (and the damn FPS bug). This challenge feels more like design challenge not piloting test, and that would also get things like slingshots out of the way hehe.

(I think the next way to improve is slingshoting of Eve and Moho, or maybe even going to Jool for slingshot into super low Kerbol Pe where rest of the burn is done - kind of like augmented bi-elliptic transfer)

Hehe i knew 5100 isn't Dv but my ship due to lower TWR never even reached 4800m/s inside kerbin SOI .

Hope you find that 4000m/s ship, I'm very curious.

Hi guys. I just created a small rocket in 10 mins wich on first try reached (i didn't write down the numbers but on map its around 3 or 4 times the distance from Kerbin to Mun), but after adding more fuel for second try, I was able to escape Kerbin's gravity and am now in orbit around Sun travelling 10.5 Km/s. It has 7 liquid fuel engines (middle +6). Engines are LV-T30 each supplied with 3 largest fuel tanks for their size. The SSTO has 38 parts and fullfills all of the requirements for challenge.

If you want to get an entry try to upload some pictures . Although it looks like OP is a little inactive so i wouldn't count on it .

After you escape Kerbin SOI, you can start counting maximum altitude above Kerbol (at the Aphelion). Try to get Ap past Jool orbit. Good Luck!

Cheers!

Edited May 10, 2013 by Nao

[lump]

it was much the same as the one i just used, i've been probing around the kind of design path i took and have found some favorable results (over 3000m/s) but not the one i had, i will find it though and when i do, SSTOs will pretty much be over, i will try and go to 5000 but after that it gets pretty pointless. SSTOs are still my favorite though and once I've peaked there distance i will start to form bases and networks and once reasorces come in i will have a complete network.

[lump]

Hey guys, sorry this post is so late, I've been dead for a while but I HAVE FINALLY DONE IT! a SSTO rocket that has well over 4000m/s in fact with good piloting i have n doubt it could get close to 5000m/s!

It was one of many variants from my best base design and has around the same fuel as my first 3000m/s one.

it was actually quite easy and took around 3 hours from start to get here, it seems as it is getting easier and easier

I only have this one pic but will upload more tomorrow of the actual ship.

this is a picture of the ship breaching the 4000m/s mark, as you can see i am going towards the sun as it is much harder to test past 2700m/s on a sun escape trajectory but going inwards i know that 4000m/s will get you between 900,000,000 and 1,000,000,000 meters with a perfect burn and the periapsis of my ship is 700,000,000 so well under the limit.

I have named it landmark 3 as it is my third notable SSTO achievement, first being smallest to escape kerbol, second being smallest to 3000m/s and third being this.

Edit: managed to sneek a few more before sleep:

the rocket talking off, i fired two of those boosters when i did not need to and wasted a tonne of fuel but i needed an orbit fast before bed.

Glamor shots:

Edited May 21, 2013 by lump