How to build sky cranes.

[Engineer of Stuff]

I need some help building a sky crane. Can I have some tips on building them (and flying)?

Please post pictures (no .craft, it is for a career save).

Thanks!

Edited December 4, 2014 by Engineer Of Stuff

[Zylark]

You don't want a sky-crane. You've been looking too much at NASA videos. What you want is a bog standard lander that just happen to have enough space underneath to deliver some payload to the surface of some moon or planet or whatever.

How that looks and performs depends entirely upon where you intend to deliver that payload, and how big that payload is. And even then, a separate craft for delivery is not necessarily the best solution.

[diegzumillo]

There's nothing similar to ropes or strings in the current parts available.

[Slam_Jones]

If you are still determined, KAS adds a number of parts that can be used (in theory) in a similar fashion to what you're thinking of. Whether they will actually work how you want them to, or if they're even slightly efficient, however, is beyond my knowledge. I may try something like this later for sh*ts n giggles.

[Landge]

Not technically skycranes, here are a couple of landers I made. The left one ditches the engines once the rover lands, similar to a skycrane. The larger one on the right is capable to redock with the lander and return to orbit.

Edited December 3, 2014 by Landge

[Heagar]

A real skycrane NASA-like (as for the rover curiosity) i wouldn't suggest. You then would have to have four ropes to release at the same time. Resulting in a "slightly" more wobbely craft to stear.

If you would use one rope only the payload would twist beneath the crane, makeing a save landing impossible.

If you want to build a skycrane kerballike in KSP you have already one under the stock crafts.

But because the burntime is too short and the propulsion too strong you can alter that design to something like this:

Something for you to notice, if you plan to drop "whatever you want" on the surface of a planet/moon:

A skycrane itself have mostly a limited fuel quantity.

My example could land on a Minmus sized planet/moon on it's own. On the Mun if a beneath attached retrorocket have delivered the payload to a distance of 500 m to to ground to be on save side. On Kerbin if at least 2/3 of the fuel is used up, Otherwise the crane would not be strong enough to lift the rover in the last few seconds.

The ammount of fuel and the power of the engines should be planned for one or two possible kinds of "gravity sources" (planets/moons) for a given payload. One thing you should test on the launchpad during WIP is if the engines are damageing the payload or not, especially if your engines have more thrust and a wider gimbal range. Aaand: Test the seperation as well!

The flying is simply as every other rocket, exept the landing: Slightly above the ground or on it you release the crane witch should have enough fuel for at least a few seconds. Because it will afterwards descending again the crane should:

• be high enough that due to the rotation of the planet/moon an chrash onto the payload is avoided or - if the payload is a rover - you can drive away
  
• at landing tilted slightly to one side in a manner, that he will accelerate in that direction and crash beside the landing site
  

[The Yellow Dart]

These aren't the best pictures ever, but this also isn't the best skycrane craft ever either. As stated above, a true skycrane can't be built stock since there are no cables, etc. This one is made to land completely, then release the rover, but you can also make a disposable one like the above post and make one that can hover low over the surface, decouple the rover, then fly away to crash somewhere else.

I've also made one more recently that was very nice and simple (no pictures at present). It used the smallest 2.5m tank as a base with a docking port on top, then had the 2.5/1.25 adapter below with 2 of the attach node thingies (fake docking ports) and 2 lv909s on them so that they point outward. In the middle there was a probe core, and docking port jr. where the rover attached and detached, it was a small rover similar to the one in the post above. For legs, I used 2 long girders on either side of the tank pointing down, with 3 of the medium landing legs attached to the sides to make it nice and stable.

edit: That first rover was actually part of a set of Mars One vehicles that I built: http://imgur.com/a/1Lmaj#0

Edited December 3, 2014 by The Yellow Dart