Smallest SSTO with orange tank payload [STOCK 1.0.5]

[Kergarin]

Congratulations Nefrums

 

@Coga19000: 

I'm sorry, but the rules say: 

" ... and return your SSTO with full orange tank as cargo to runway." 

That means one piece 

[Coga19000]

@Kergarin Well, I was rreferring to the part of the mission where the SSTO return without the orange tank. And no, my grand idea was NOT to land the orange tank by its own power (or by itself)

Anyways, I'll take that as a no. Doesn't matter though; that's that docking ports are for after all.

[Kergarin]

@Coga19000: 

Sounds interesting  that's actually not defined in the rules. Normal level just says you have to land safe at KSC runway.

Maybe you just give it a try?

 

I didn't expect it to be that hard, to be the one who hast to decide the rules 

[Coga19000]

@Kergarin Heh, don't worry too much. It's not every day you encounter someone willing to go at length to exploit a miswording in the rules.And yet, better to have some things cleared out by the beginning instead of having the misinterpretations sxrew everyone up later on.

It's not like me to try to break the rules either;I'm normally a stickler for them, especially when realistic designs are concerned. However, I have to admit I'm pretty fond of my little idea; especially because I have not encountered it somewhere else by now.

[Kergarin]

@Coga19000: 

No its ok. I'm really curious and looking forward to see your idea now . And I think it's important to have some innovative concepts here.

 

I have added categories to the ranking: 

- closed cargo bays for classical designs

- open cargo for some more "crazy" designs 

So it's more fair to compare. I think. 

 

When starting this, I had much harder rules in mind. But I have realized, that would lead to all SSTOs looking nearly the same.

[Nich]

Well I have come up with a 69.18t puller type craft using 3 rappiers.  It probably took me 100 tries to land it on the runway as the front gear is too close to the rear after detaching the main tank.  It actually tipped over when it stopped lol.  It has 2 senior docking ports so level 2 is possible.  I will try tomorrow but I don't think I will be able to get the wings on the tank to line up perfectly which could make flying really really painful.

 

 

 

[PacThePhoenix]

I promised I would have fun with this challenge, and have I fulfilled? Nope XD. Thus far, the build process has been gruellingly challenging, more difficult than it really needs to be. The reason for this is the nature of my design. I'm done working on it for today, but I estimate I'll be able to show it off by Wednesday (maybe). I'm going for something I'm sure you'll find amusing, but it is being kept a secret for now. My only hint (and a really terrible hint at that) is "Beluga" .

[Nefrums]

@PacThePhoenix That is one ugly plane!

 

@Nich  Nice one,  You probably had the same problem as me, way to little lift while landing.   

But I think you missed the rule "Do not add engines to the payload."

I think you had it right that 3 rapiers is enough.   I'll try to build a ship using that.  65t should be possible (55% payload fraction). 

[Nich]

 Damn so close what if I said that is just an air breathing/LFO rcs   My 4 Engine variant didn't have an engine on the payload but I could not get it below 72 tons.oh well at least I don't have to try to bring it down now that'll save me about 12 hours today

[Kergarin]

@PacThePhoenix: still curious 

@Nich: I'm afraid the engine on the tank does break the rules a little. The engines should be part of the SSTO. Really sorry for that 

 

Hm... I don't know if I should try an open design or optimize my closed one first...

Oh and have to do the badge! 

[Nich]

10 hours ago, Nefrums said:

@PacThePhoenix That is one ugly plane!

 

@Nich  Nice one,  You probably had the same problem as me, way to little lift while landing.   

But I think you missed the rule "Do not add engines to the payload."

I think you had it right that 3 rapiers is enough.   I'll try to build a ship using that.  65t should be possible (55% payload fraction). 

@Nefrums Actually it was so draggy I had to do a powered landing which I am not used to.  It flew very nicely at 70 m/s but with power on I kept going over 100 and power off kept falling below 50 just couldn't find the right power setting / glide path.  Oh and I did have to transfer all the remaining fuel to the back which made it unstable   Had I rotated the front gear so the wheel was in front and put the other 2 gear out further it wouldn't have been half as bad.  I compare it to trying to land on a unicycle :0

[Triop]

"Not entering cause my orange tank is green ! "

* Ignore this mad man. . . 

[Nefrums]

Here is another slightly larger entry for Master:

149,5 t , 66 parts

 

[Nich]

Is that a 6 coupler or rapiers on cubics? @Nefrums It is pretty crazy flying  that thing back up the second time isn't it? SO MUCH THRUST lol

Still waiting for my badge *tap *tap *tap  

[Val]

Here's my entry for Master.

143.9 t takeoff weight. 79 parts + 3 for payload.

Sorry, @Nefrums. You just posted your entry.

Craft file

Sorry, for 52 minutes of unnarrated, unannotated and musicless video. I don't have any video editing software that will allow me to work with and output video recorded in 2560x1080, without adding black bars above and below. 

But I do point with mouse every now and then. 

Index of interesting points in the video (also available in description)

Spoiler

0:37 Liftoff and speed build up
1:42 Ascent begins
3:05 Max Temp at 15 km altitude
3:38 RAPIER Closed Cycle
4:38 MECO
5:58 Circularization at 80 km
6:20 Undocking starts
7:18 Undocking complete
8:32 Setting up deorbit
9:54 Deorbit burn
12:30 High AoA aerobraking complete
14:10 Passing the mountains
16:00 Lining up to runway
17:00 Final approach and Touch and Go
17:30 Second Ascent
18:58 RAPIER Closed Cycle again
19:25 Second MECO
20:35 Circularization at 72 km
21:00 Setting up Rendezvous with Mechjeb
21:35 Warping to Node and viewing other planets while waiting
25:55 Warping past the Node and making new transfer
27:55 Matching speed with target
29:33 Approaching target slowly
37:10 Docking in Darkness
38:27 Warping to get KSC in daylight
40:30 Setting up second deorbit
41:28 Second deorbit burn
44:52 Losing control at 31 km altitude
45:30 Regaining control at 25 km
47:04 Approaching the mountains in cloud cover
49:15 Taking manual control and aligning to runway
50:25 Final approach and gear deployed
51:13 Touch down

Edited February 25, 2016 by Val
Index fixed

[Nich]

Attempting to make a recovery system :/ Apparently wheels hit tanks but tanks pass through wheels in the kerbal universe lol  I may have to steal your 2 point docking system

[Nefrums]

8 hours ago, Nich said:

Is that a 6 coupler or rapiers on cubics? @Nefrums It is pretty crazy flying  that thing back up the second time isn't it? SO MUCH THRUST lol

Still waiting for my badge *tap *tap *tap  

That is a engine mount plate with 3 bi-couplers.

The TWR is a bit crazy on the second accent. Ship is less than 10t / Rapier.  Actually had to throttle down to avoid overheat.

 

8 hours ago, Val said:

Here's my entry for Master.

143.9 t takeoff weight. 79 parts + 3 for payload.

Sorry, @Nefrums. You just posted your entry.

Well done @Val!  Now I have a reason to improve my design!

And to be honest there is a lot of room for improvement in mine.  It worked the first time, (or at least the first time i flew it past Mach 1).  I had way to much OX, and barley used the Nervs.

I think the second accent can be done on LF only.

[Nich]

Ya my first attempt at a second orbit I hit 250km AP before I realized it.  Going to have to relearn how to fly with that much engine lol

[Val]

I've added an index, with links to interesting points in the video, to the description on youtube.

I've also added it in my above post.

@Nefrums, the video was my 2nd attempt. My first also had way too much OX, and too little LF.

Edited February 25, 2016 by Val

[Nefrums]

I'll try to make a second attempt tonight.    I'm thinking of replacing the  Mk3 Liquid Fuel Fuselage Short and  Mk3 Rocket Fuel Fuselage  with  Mk3 Liquid Fuel Fuselage. ie -2750 OX +250 LF.  and -14,26 t   this might be removing to much fuel, and will depend on that it is possible to do the second accent on LF only.

 

 

[Val]

36 minutes ago, Nefrums said:

I'll try to make a second attempt tonight.    I'm thinking of replacing the  Mk3 Liquid Fuel Fuselage Short and  Mk3 Rocket Fuel Fuselage  with  Mk3 Liquid Fuel Fuselage. ie -2750 OX +250 LF.  and -14,26 t   this might be removing to much fuel, and will depend on that it is possible to do the second accent on LF only.

How much TWR on LV-Ns for the second ascent? I see 0.32 in your previous attempt. How much of the ascent was done using LV-Ns?

I think, it's gonna be real hard to do LF only unless you have TWR > 0.4 and you'd need to be going close to 1600 m/s air breathing, by my estimates.

[Nefrums]

I barely used the nervs at all during second assent as i thought that i should burn the OX first.

2 nervs on a 60t ship gives about 0.2 twr  120/(60*9,81)

It might work If i manage to get a high enough angle upwards, with should be possible with the insane amount of twr from 7 rapiers on a 60t ship.

 

Edit:  In any case i do need less OX than i had before, even if i need to save a small amount of OX for the second accent.

Edited February 25, 2016 by Nefrums

[Val]

30 minutes ago, Nefrums said:

It might work If i manage to get a high enough angle upwards, with should be possible with the insane amount of twr from 7 rapiers on a 60t ship.

True.

[Nich]

Beautiful ship Val.  Reentry performance was amazing.  My only question is how did you hit KSA without checking map view?  I am pretty sure you set you burn and never checked again.  I use map view until I can see Bob in the control tower from the cockpit lol

[Val]

14 minutes ago, Nich said:

Beautiful ship Val.  Reentry performance was amazing.  My only question is how did you hit KSA without checking map view?  I am pretty sure you set you burn and never checked again.  I use map view until I can see Bob in the control tower from the cockpit lol

Over hundreds (maybe thousands) of reentries, I've developed a deorbit method, that makes it so easy (for me) to hit KSC from 80 km orbit, that I don't need to check map view. I can judge and adjust my descent based on speed, altitude and the landscape below.

Just look at any SSTO craft in my KerbalX hangar, and you'll see the Descent Profile is pretty much copy-paste on every craft, with minor tweaks, to initial high AoA and when to start diving for the mountains.

Edited February 25, 2016 by Val
Hangar link