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Tiny Shuttle Challenge


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Who can make he smallest shuttle by take off weight? 

Your shuttle must: 

Take off vertically. 

Land horizontally, on Kerbin, on land. 

Be attached to the side of the rocket, it is not allowed to ride on top. 

Use stock parts. (DLC is fine)

 

Top Scores: 

 

@Brikoleur 1,562

@EveMaster 7,650

@Martian Emigrant 23,661

@ralanboyle - 60,843

 

 

I'll get us started with this. (I assume it is possible to cut this weight in half.)

 

Edited by ralanboyle
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3 hours ago, vyznev said:

Does the shuttle need to be crewed? And does it need to be able to carry a payload (and if yes, how much)?

Negative on both counts. Mine was manned/loaded simply because I decided to make this challenge after having fun making my shuttle. 

Just now, GuessingEveryDay said:

@ShadowZone! Look, these people are attempting to beat you! In case you don't know about ShadowZone:

Yes, I am aware of shadowzone. His videos are great. He is welcome to submit his design for this challenge. Perhaps you can beat it. 

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Just now, Brikoleur said:

Does it need to land on land, or is a horizontal water landing allowed?

NVM, re-read the description

Yeah, I did that for a couple reasons. 

At first I wanted everyone to land on the runway but getting rid of that opens it up to a lot of people who haven't mastered that.

Still, I wanted the shuttles to be flyable/landable. Requiring you to land on land shows that it isn't just an unguided reentry and that it actually stays together on touchdown. (and you need landing gear...probably)

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I just did a round trip with a prototype that weighs 1,802 kg on launch (shuttle + booster, not including launch clamp). Doesn't count unfortunately because I had a little mishap on landing and lost a nose cone. That was pilot error though and I'm now entirely confident it will work. 

I'll refine it a bit further and then submit...

Edit: All right, here it is -- a pretty ugly launch and gravity turn but hey, it got it up there, didn't it? 

As stated, 1,802 kg at launch, not including launch clamp. Turns out that a drag strip makes a perfectly good landing skid! -- I also appear to have something screwy about my graphics settings as there's no shadow...

 

 

Edited by Guest
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Just now, Brikoleur said:

I just did a round trip with a prototype that weighs 1,802 kg on launch (shuttle + booster, not including launch clamp). Doesn't count unfortunately because I had a little mishap on landing and lost a nose cone. That was pilot error though and I'm now entirely confident it will work. 

I'll refine it a bit further and then submit...

Edit: All right, here it is -- a pretty ugly launch and gravity turn but hey, it got it up there, didn't it? 

As stated, 1,802 kg at launch, not including launch clamp. Turns out that a drag strip makes a perfectly good landing skid! -- I also appear to have something screwy about my graphics settings as there's no shadow...

 

 

Love it! Good job. 

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6 hours ago, Brikoleur said:

As stated, 1,802 kg at launch, not including launch clamp. Turns out that a drag strip makes a perfectly good landing skid! -- I also appear to have something screwy about my graphics settings as there's no shadow...

Very nice! :) That design also looks rather hard to beat. I do see a few potential ways to maybe shave off a few kg here and there, but nothing that would make the result look significantly different from yours. Maybe if I used an SRB

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SRBs are heavier.

It has a quite a bit more dV than it needs so you could certainly leave one of the tanks half empty. You can leave off the antenna if you have CommNet disabled or have powerful enough relays to talk to the core’s internal antenna. And you mightbe able to swap out the Spark on the shuttle for an Ant, but that would make thrust torque a real problem so I don’t know if it’s feasible. That would let you drop one tank, possibly even two.

I can’t really think of anything else.

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13 hours ago, Brikoleur said:

I just did a round trip with a prototype that weighs 1,802 kg on launch (shuttle + booster, not including launch clamp). Doesn't count unfortunately because I had a little mishap on landing and lost a nose cone. That was pilot error though and I'm now entirely confident it will work. 

I'll refine it a bit further and then submit...

Edit: All right, here it is -- a pretty ugly launch and gravity turn but hey, it got it up there, didn't it? 

As stated, 1,802 kg at launch, not including launch clamp. Turns out that a drag strip makes a perfectly good landing skid! -- I also appear to have something screwy about my graphics settings as there's no shadow...

 

On a side note, I don't know if it is one of the last updates or part of Breaking Ground but you can remove one engine's throttle from the throttle action group.

You also have 3 or 4 additional "custom" axes you can assign in the binding options and then in the action group manager.

I've binded a extra axis to the side buttons of my mouse that I use for some robotics/independent throttle.

 

47 minutes ago, Brikoleur said:

And you mightbe able to swap out the Spark on the shuttle for an Ant, but that would make thrust torque a real problem so I don’t know if it’s feasible.

Maybe a couple of Sepratron SRBs on low thrust on the shuttle just to counter balance the Ant?

Other than that I can't see any significant design variation either.

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44 minutes ago, Master39 said:

On a side note, I don't know if it is one of the last updates or part of Breaking Ground but you can remove one engine's throttle from the throttle action group.

You also have 3 or 4 additional "custom" axes you can assign in the binding options and then in the action group manager.

I've binded a extra axis to the side buttons of my mouse that I use for some robotics/independent throttle.

This is very cool, I didn't know you could unbind the throttle. That would be just the ticket for this. Maybe I'll try a variant with that and maybe a few more tweaks (and strip out the antenna as it isn't strictly necessary). Would also be nice to get a better launch, this one was mega ugly. Thanks!

 

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Okay I couldn't leave well alone. Thanks to @Master39's tip about decoupling throttle on one of the engines, I managed a much cleaner start and saved a lot of dV.

I was able to leave off one entire Oscar and got the take-off weight down to 1,562 kg. I had over 200 m/s to spare when returning to the runway, too. No doubt there's room for a bit more optimisation there still but I kind of like this one, it's surprisingly easy to fly too.

I published the craft file in case any of you want to give it a spin, it's here: https://kerbalx.com/Brikoleur/TINIER

 

 

Edited by Guest
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1 minute ago, sevenperforce said:

Trying to figure out how to strip this down further. Thinking about making it a little more like Energia-Buran.

If you can get it to work with an Ant instead of a Spark on the orbiter, that would save a quite a bit of weight. The thrust is majorly unbalanced then though so it's not obvious.

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1 hour ago, Brikoleur said:

If you can get it to work with an Ant instead of a Spark on the orbiter, that would save a quite a bit of weight. The thrust is majorly unbalanced then though so it's not obvious.

I've got it down to 1.2 tonnes with no thrust balancing issues but even so that is not nearly as far down as I expected to be able to get. Trying to refine the ascent profile so I can actually make orbit.

EDIT: currently 220 m/s short. Not sure if cleaning up the launch profile will give me enough.

Edited by sevenperforce
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Okay, got it up. 1.32 tonnes and it makes orbit with 48 m/s of dV to spare -- enough for a deorbit for sure.

I've tested landing, which is...dicey. But doable. Haven't yet tested re-entry but that's next. 

Spoiler

A few design points:

  • The small fin looks offset but its center of lift and center of mass are in the correct place.
  • The fin is also angled up slightly to provide lift at zero AoA, which helps both with control on ascent and with the final approach and landing.
  • The Oscars are all set to empty from the bottom up to keep the center of mass as far forward as possible.
  • I might have been able to get away with only a single battery on the orbiter but I wanted some reserves because I still don't know how hard I'll need to push the reaction wheel on descent and landing. Splitting the batteries follows crossfeed rules.
  • The Ant is inefficient at sea level but it needs to be there to offset thrust. As the vehicle climbs, so does its thrust, which is good because of the shift in CoM

 

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Oh nice!

I've got one that's 951 kg on take-off and should make orbit with some really hot-shot flying but I haven't gotten it there yet... quite. Similar configuration to yours, except I'm using a Twitch instead of a Spark on the thruster -- it's lighter and has sufficient power and is also easier to offset -- and twin Spiders on the orbiter. It's not terrifyingly torquey but it is twitchy and I lose too much dV to drag because of that.

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16 minutes ago, Brikoleur said:

Oh nice!

I've got one that's 951 kg on take-off and should make orbit with some really hot-shot flying but I haven't gotten it there yet... quite. Similar configuration to yours, except I'm using a Twitch instead of a Spark on the thruster -- it's lighter and has sufficient power and is also easier to offset -- and twin Spiders on the orbiter. It's not terrifyingly torquey but it is twitchy and I lose too much dV to drag because of that.

Crap. Back to the drawing board then.

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24 minutes ago, sevenperforce said:

Crap. Back to the drawing board then.

I haven't gotten it to orbit yet. It might not even be doable. Theoretical dV is > 3500 m/s though so it ought to make it...

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9 minutes ago, Brikoleur said:

I haven't gotten it to orbit yet. It might not even be doable. Theoretical dV is > 3500 m/s though so it ought to make it...

I tried to get fancy with a monoprop orbiter, a Twitch core, and Spider side boosters a la Energia-Buran, but no dice.

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