KAS Crossbow: Constant escalation of insanity.

[lucidLemon]

I had downloaded KAS to create a .GIF of a small scene. I knew it was a handy mod, but I didn't have any other plans for it. But then I had a small idea.

I bet I can launch probe cores with this mod

It seemed harmless, so I gave it a shot.

I created a something pretty unimpressive and enormously difficult to fire. Once payload was released and moving, I didn't know how to separate it from the cords. I opted for sepratrons pointing at the plate attaching them. They overheated the plate and destroyed it, releasing the probe. It only launched the payload a few meters.

What mattered, though, was that it worked at all. It was a small start, a step in the right direction. I couldn't just leave an idea like this alone.

I quickly figured out how to launch the cores reliably. I separated the core before launch and held it in a bucket. Arms were also added, when tensioned up, the arms bent back, like a true crossbow.

It managed to fire the core a modest, but impressive distance. As the distances increased, so did the danger. I snapped one of the wires by over-tensioning the bow; the bucket whipped to the side and slapped an unfortunate Donfel Kerman a hundred meters away.

I got another silly idea, I emptied the bucket and stuck a kerbal inside it.

I didn't put much tension into the shot, and watching them bounce around was hilarious.

It was a taste of things to come.

I increased the angle of the bow, now it pointed at the optimal 45 degrees. I was reliably shooting over 100 meters now.

Unfortunately, I couldn't get the cables shorter without the bucket spazzing out. I added another set of arms to brace the original pair, increasing the tension it could store.

300 meters. Then I realized that kerbals, with their tiny air resistance, made great... test pilots. I ditched the probe cores and switched to live ammunition.

400 meters! 500 meters! It just kept getting better and better. I realized though, that maybe I could do better with a single set of arms. The current setup had one that pair that bent back, and another pair to attached to it for bracing. I removed the original set of arms and attached cables from to the second, sturdier pair directly to the buck.

It was angled lower because the arms bent up after firing, this wasn't a reliable way to shoot things. More struts had to be added to keep things under control.

This managed to consistently score 500 meters. I was getting excited now. I didn't know how much more I could improve my design. The strut count kept increasing, making the arms more rigid. By now it was more of a slingshot, although I still thought of it as "My Crossbow."

Then I got another little, ridiculous, insane, absurd idea.

Make it mobile.

This added a whole slew of new challenges, making it balanced, tipping it over, etc. The biggest was phantom torque, as you tension up, the game gets weird; the ship will want to spin on its own. Without the launch clamps holding it down, it did exactly this. I added four grappling hooks around the edges that could be ejected into the ground to anchor it down, KAS really saved the day!

I continued testing on it, I was astounded by how effective it was becoming. I felt I had reached a peak with this design, and that it was ready. I had had one thing in mind ever since I first removed the launch clamps.

Did you guess "Put it on the Mun?"

Because that would be exactly right. I did it. Did it explode in midair? Yes. Did it crash into the regolith? Yes. Did it hilariously fall helplessly onto its back? Absolutely. I was on the Mun now though, and it was time to get the firing range ready.

KAS came to the rescue again, the hooks were both able to get it upright and angle it for the perfect shot. It finally got a name too! I dubbed it the "Arcum Lunae."

I was amazed, but then I just had to get another idea. I wondered if I could reach Munar orbit. That would be an amazing achievement, not only a first for me, but a first for anyone ever! I had to give it a go.

I was off to a good start.

I coasted to apoapsis with last of my fuel...

And I circularized!

For me, this moment was absolutely beautiful.

You know that feeling you get when you land on the Mun for your very first time, how you smile ear to ear and want to shout and jump? This was better. I still get a little shaky with excitement just thinking about it.

Development still continues on the crossbow.. In it's current generation, the bow has four arms again, but this time they're all connected to the bucket. The results speak for themselves.

News about the next update has discouraged me from sending another to the Mun. Once .21 comes out though, I'll be ready to put this baby on the Mun. I imagine a setup where I have a small craft performs a rendezvous with the kerbal and takes him back to a Munar space station. At the station there can be a mass relay to slow them down and allow them to land back at the crossbow.

Who knows? I might even try putting it on other planets.

Update:

Alright, I was discouraged, but a post reminded me about the Dres Canyon. I couldn't pass it up. I forgot a decoupler, so I had to lithobrake my lander away. That's why the landing site is littered with debris.

I'll edit in more details later, it's time to stop putting off sleep.

Little Update:

Here's a GIF set of me firing it.

And here is a reddit post with a save file, craft file, and instructions.

I'll probably make an album of the journey there, but for now, have this screenshot from me testing lithobraking.

Edited July 11, 2013 by lucidLemon

[Cby]

This has got to be one of the most beautiful things I have seen in Ksp. Bravo.

[MacDuckenstein]

Next you should try to put this on Minmus.

Also try to improve it so you could launch kerbals up to orbit the Mun without the jetpacks.

[lucidLemon]

Thanks, Cby!

As for putting it on Minmus, I'm not launching it again anytime soon. You're free to fly it yourself though. Be warned, it is prone to falling over, exploding, and many other typical KSP ailments.

And launching directly into Mun orbit? Nope. Not gonna happen. It takes 560 m/s for a low orbit around the Mun. Basically, there is a small time between every "step" that KSP calculates physics. Even with the launch speeds I have now (90-140 m/s), the bucket moves so fast that in the time between "steps" it occasionally gets ahead of the payload and leaves it behind.

[Tw1]

I love it! That's brilliant.

Quite different from the sling I attempted, (Modified the KAS cable to retract at crazy speed, pulled itself apart each time, didn't go very far.)

But yours is a work of fine engineering. Impressive, will be watching to see what you manage with it in future.

Imagine timing the launch so you were almost at the station, and then using the jet pack to rendezvous with the station.

Edited July 10, 2013 by Tw1

[astropapi1]

Now put it on gilly. Escape velocity directly from the ground.

[el_coyoto]

Slap some landing wheels, and turn it into a very Kerbaly rover that uses its pilot as working mass.

The only limit to its range is the pilot's ability (or willingness) to return to the crossbow rover...

Awesome idea and execution!

Edited July 10, 2013 by el_coyoto
fancy formatting

[lucidLemon]

I tried sticking rover wheels on about midway through development, but I never strutted up the wheels properly, it still got a 300 meter shot though.

Also, I told myself I was waiting for .21, but then I saw a post about the Dres canyon.

My new project has just begun.

Edit: About to begin the transfer, wish me luck.

Update: Forgot a decoupler between the lander and the crossbow.

LIKE THAT WOULD EVER STOP ME.

HAHAHAHA

PRECISION LITHOBRAKING TIME.

Edited July 11, 2013 by lucidLemon

[lucidLemon]

Update: Added to original post! I did it! I built myself a ~700 ton rocket and landed that bad boy on Dres.

[Tw1]

Well done with the lithobraking! Great job.

[Jones-250]

Whaaaat is this? I... I must t-try this out! At once.

[Basilo1146]

You inspired me. I have currently begun work on my own crossbow, but things always either fall out of the bucket or get caught on its lip...

[lucidLemon]

Whenever things fell out for me, it was because the craft (or just the bucket) was shaking. Try strutting things up and not overtensioning the cables.

As for getting caught on the lip, I can't really do any trouble shooting without a picture.

[lucidLemon]

Alright, I'm heading down a new line with this project, I'm pretty sure I've gone full slingshot now.

It's incredibly stable, and can take sharp turns at full speed. Ejecting the side hook to make extremely quick turns (in true Batmobile style) doesn't work, unfortunately.

After arriving at some chosen destination, the bucket is set down.

The "towers" split up and anchor themselves down with grappling hooks. A Kerbal attaches the bucket's hook to the ground.

The test pilot is put in and the cords are veeeery carefully tensioned up.

Fire!

Not bad for an early prototype.

It's time to pack up, the bucket is pulled up and reattached to the towers after a bit of fiddling around.

Some of the connections look a little wonky, but it still drives perfectly fine!

[Designer225]

Ha, very... old, Medieval, and crazy!

[TheOrqwithVagrant]

This is awesome! Now take it to the next level make a big one that launches a smaller one, which in turn launches Jeb! Perhaps a two-stage slingshot launcher could at least reach orbit on Minmus

[Mach56]

A kerbal can reach orbit from Minmus/Gilly/Pol/Bop from the ground.

[Rainbowtrout]

This is just epic. How many kerbals died in testing?

[tntristan12]

I would love to see how this does on Gilly. Bet it reaches escape velocity.

[Devo]

haha excellent stuff