Workhorse Rocket

[I Fell Offa Fly]

Playing kerbal one thing I've noticed is that I have a lot more fun designing spacecraft than the rockets that lift them. I need a medium lift rocket that I can simply attach payloads to as I please.

Rules:

-Must be able to lift at least one full orange tanks worth of mass (36t) into an 80km circular orbit around

kerbin.

-Must have no more than 3 stages (strap on boosters not included)

-Must be stock

-Must not use asparagus staging

-Must be low cost (.24 is coming)

-Bonus points for using parts acquired as early in the tech tree as possible

Good luck

[Pds314]

What optimal rocket calc gave me when I put exactly your constraints. Maybe I should have forced same-size fuel tanks?

Stage Part x Cost Mass (t) Delta-V (m/s) TWR Time (s)

0

Payload: 36t

0 / 0 36.000 / 36.000 0 / 4601 0.00 0.0 / 197.3

1

TR-2V Stack Decoupler

FL-T100 Fuel Tank

FL-T200 Fuel Tank

Rockomax X200-32 Fuel Tank

Kerbodyne S3-7200 Tank

Kerbodyne KR-2L Advanced Engine 8785 / 8785 67.203 / 103.203 2726 / 4601 2.47 79.9 / 197.3

2

TR-2V Stack Decoupler

Oscar-B Fuel Tank

ROUND-8 Toroidal Fuel Tank

FL-T100 Fuel Tank

FL-T400 Fuel Tank

Rockomax X200-8 Fuel Tank

Kerbodyne S3-14400 Tank

Kerbodyne KR-2L Advanced Engine 8210 / 16995 96.042 / 199.245 1874 / 1874 1.28 117.4 / 117.4

[Pds314]

Cheapest cost I could get was 14250, which is astonishingly cheap. It basically consists of an S3-14400 tank, KR-2L engine, and 6 radially attached giant boosters on decouplers.

I'm guessing that 14250 cost is the optimal for getting 4600 Delta-V, having enough thrust, 3 or fewer stages and not using asparagus.

Wow, the top 2 lifters by mass differ by only where they put a Round-8 toroidal tank and which one gets 1 more m/s Delta-V.

How you are gonna stack an orange tank on top of that is entirely up to you though.

P.S. Do engineless external drop tanks count as asparagus? If not, My rocket might reach an astounding 20.4% payload fraction.

Edited July 11, 2014 by Pds314

[Pecan]

LV-40-P + Fuel Module Launch

Identity: LV-40-P – launch vehicle

Purpose: Kerbin launch, 40t.

Statistics: 275.75t VAB/85.75 dry, 16 parts, cost 31,780.

Design: 2 parallel-staged

Construction: RC-L01 RGU, sr. docking port, ADTP-2-3 adapter, S3-3600, S3-7200 and S3-14400 fuel tanks, KR-2L engine. 2 x radial decouplers, LFB-KR1x2 boosters, nosecones.

Action Groups: abort:shutdown engines, 3:toggle them

Performance: (Kerbin) TWR 2.4. 4,860m/s

Chapter 7, section 7 of the tutorial in my signature.

As it says above this is parallel staged but what have you got against asparagus?

[Mathman]

I need a medium lift rocket that I can simply attach payloads to as I please.

Rules:

-Must be able to lift at least one full orange tanks worth of mass (36t) into an 80km circular orbit around

kerbin.

-Must have no more than 3 stages

-Must be stock

-Must not use asparagus staging

-Must be low cost (.24 is coming)

-Bonus points for using parts acquired as early in the tech tree as possible

Entry: CL-Lifter 36 for dumb payload orbital delivery.

Part Count: 23 Weight(w/o payload) 236.4ton

SAS Equiped - Subassembly craft file

Cost: k 34,830 (w SAS) [ k 33,480 / 20part w/o SAS ]

Maximum Tech Level: 6

Staging: 3 stages, In-line staging - 4 strap on boosters.

4736 m/s delta v @36t (vacuum) TWR(Kerbin) 1.72

---

Available as a sub-assembly for ease of adding to your payload with two clicks.

It may be cheap, it may be light, but it looks smooth going up. It is also available early on in carrier game (only level 5 with a few level 6 items), and will also fly well using reality mods being tall and slick. A truck, but a Volvo as opposed to a Peterbuilt.

Edited July 13, 2014 by Mathman
Ultralite version

[Pecan]

What optimal rocket calc gave me ...

How many solutions did it run through to come up with that, and how long did it take? Last time I used it I think I left it running for about 10k valid solutions while I went shopping. It did produce the goods though :-)

[Pecan]

-Must be able to lift at least one full orange tanks worth of mass (36t) into an 80km circular orbit around kerbin

Maybe it's because I've been up all night but I don't get it. Go on, I'm sure you're dieing to tell us.

[Mathman]

Not really. (dying to tell that is) I was just pointing out that the goal is a 36 ton payload, not necessarily a Rockomax Jumbo-64 tank.

That being said, I might also point out that while Mech Jeb was NOT used to launch the test sample, it took careful control of the gravity turn to ensure maximum efficiency at full load. This is a minimalist design.

BTW - Yes, I did change my entry. I saw a way to a slimmer (and cheaper) design while sleeping and made the change. Still not as cheap as the other entry, but still only using a maximum of tech level 6 parts as opposed to the other entry which uses level 8 parts.

[Mathman]

This looks like the booster has no guidance or reaction control. Am I wrong here or does this require the payload to have both of those and did you include their cost in the total cost?

[Pecan]

...I was just pointing out that the goal is a 36 ton payload, not necessarily a Rockomax Jumbo-64 tank.

Ah right - what got me was that having carefully stressed the 36t requirement your original was announced as "32t". Your new one looks very good - the orange at top and bottom is a nice aesthetic. I just threw in the standard 40t launch-vehicle I use since this isn't a proper challenge - what would I know about grindy-science tech-levels and what difference will it make in a couple of weeks anyway ^^.

[Jodo42]

EDIT: I managed to get an even further stripped down version of this rocket working. May I present the DumbOrangeV2:

She isn't pretty, and she isn't easy to fly, but she does exactly what you want her to do.

I call her DumbOrange, since it's lifting an inert "dumb" Orange tank as a sample payload. Obviously you could put whatever you want on her. She's been stripped down to the bare minimums needed for this challenge, with luxuries like SAS or struts excluded to cut down on costs.

3 stages. DumbOrange will scrape her way by into an 80KM orbit with around 50 units of fuel left. Boosters decouple at roughly 8K, central stack LFB gets you to suborbital and some careful flying with the insertion stage (a half-orange and a Poodle) will get you into the desired orbit.

On the pad she masses in at just under 220 tons and a mere 19 parts. The batteries are included to prevent loss of power during ascent, as the LFB lacks an alternator for some silly reason and putting RTGs would bump her up to tech 8. DumbOrange only needs tech 6 unlocked to be used.

The total cost of a DumbOrange is only 29,680 kredits, minus payload. Extra struts or SAS modules could be added for minimal costs. I haven't tested the stability of this idea, but removing the 4 struts could put you a thousand kredits lower.

Edited July 14, 2014 by Jodo42

[Pecan]

Slighly off-topic, I'm messing-around with a reusable launch-vehicle for a 40t load at the moment. This can perform a powered landing (drogue assisted) after delivering the centrally-mounted payload to 100km orbit:

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[Mathman]

what difference will it make in a couple of weeks anyway ^^.

Somethings happening in a couple of weeks? Tell me more. As for low tech, when you are working in career mode, two levels means a LOT of research. Besides, the challenge did say bonus points for low tech. If it weren't rocket science, it wouldn't be a challenge. ;-)

[Mathman]

Jodo - Rock bottom! Beats me. I suppose that the two side KR 1x2 rockets can be considered as strap on boosters and not asparagus staging since there is no fuel connection between them and the core. Sort of like splitting hairs but you know the old saying, "you can't make good hasenpfeffer without splitting a few hares.

[Mathman]

EDIT: I managed to get an even further stripped down version of this rocket working. May I present the DumbOrangeV2:

Jodo, I was able to duplicate the performance, but not the weight and cost.. (35,970 k and 233,434t). Do you have a craft file to share so I can see where I went wrong?

[Pecan]

Somethings happening in a couple of weeks?

Well, yeah - 0.24 should be out by then, with a complete re-make of career mode. Preparing anything for career-mode as it is at the moment could be pointless. When I said "what difference will it make" I didn't mean "it won't make any difference" but "we don't know what difference it'll make". Lol, main point is I have no idea what tech-level things are anyway because I don't grind for science.

[Jodo42]

Jodo, I was able to duplicate the performance, but not the weight and cost.. (35,970 k and 233,434t). Do you have a craft file to share so I can see where I went wrong?

It's possible I did my math wrong, but here you go.

https://www./?kzc977447q8khxa

EDIT: I redid the math, and I got 31,280, which keeps it in the "lead" but just barely. On pad mass is 219.85t, 183.85 when the payload mass is redacted (I include the probe core needed for control as payload mass).

Something I think we should keep in mind is that current prices are very screwed up. The largest 3.75m tank, for example, only costs 2,900. The orange, however, costs 10,500. I was able to cut costs significantly by using 2 half oranges instead of 1 orange.

Edited July 14, 2014 by Jodo42

[Pecan]

Something I think we should keep in mind is that current prices are very screwed up.

Yeah, and this is one of the things we know has been changed for 0.24, but we don't know what's been done yet.