Crane Vehicle Tips?

[Dortmunder]

Hey all.

I've got a crane built, and I'm trying to have it able to lift/move about 10 tons around without being overly off balance.

In the picture below the piece is a bit over 10 tons, but driving around is a little unstable. If I slow too much or hit the brakes etc. it tips over.

Any suggestions on what to do to make it better? Maybe the front wheels further up/wider? I was going to add some more weight to the back, but couldn't find any good parts that were small and weigh a lot to throw back there.

I'm just about to head off to bed, but wanted to post this before that. So thanks in advance for any help

[Spyritdragon]

I'd advise you to go to the VAB and find your centre of mass. Then add 10 tons of weight at the end of the crane and fine the centre of mass again. Try to find a configuration where both are the same distance from the middle, or where the loaded one is in the middle, depending on how much driving youll be doing loaded and how much unloaded.

But in all honesty, the best working designs ive seen here have a frame that goes over the load, with KAS or ports on the inside of the 'roof', therefor making a reasonably easy pickup, and it allows you to have your weight suspended below your centre of mass when unloaded.

[superm18]

how about having a dockingport in front from wich u can dock with counterweights of different weight? u know like a tractor...

or have a "bucket" of sorts in front to hold the weights if the dockingports are to wobbly or week

[SkyHook]

I have found that landing legs help greatly when designing cranes. Drive over to the target, deploy lander legs, pickup target, drive over to destination, deploy landing legs, attach module.

[leax256]

I have found that landing legs help greatly when designing cranes. Drive over to the target, deploy lander legs, pickup target, drive over to destination, deploy landing legs, attach module.

not the problem

see below

In the picture below the piece is a bit over 10 tons, but driving around is a little unstable. If I slow too much or hit the brakes etc. it tips over.

[leax256]

try driving backwards

[Loerelau]

I was going to add some more weight to the back, but couldn't find any good parts that were small and weigh a lot to throw back there.

The KAS anchor is 1ton a piece. You could use a couple of those...

You can find my heavy lifting crane at:

http://i.imgur.com/ic16ptT.jpg

I used around 25 of them (To beat gravity on Minmus ). Crane without anchors is around 20 tons, with anchors 46 tons.

[royying]

I use to build a crane by KAS

using one winch is very unstable, unless the payload is very very light

you have to use multiple winch to exert tension on 3-axis

[allmhuran]

Add an engine or two at the back facing upwards. Use jet engines if the crane is for kerbin or laythe since they're so fuel efficient, otherwise use nuclear engines. This way you can use the throttle to adjust the amount of down-force at the rear to compensate for variable amounts of weight at the front (requires separate binds for engine throttle and rover forward/reverse!)

Edited August 27, 2013 by allmhuran

[Nephas]

I think the easiest solution would be to put the front wheels (if by front you mean the loaded side) at least in line with the load, or perhaps a bit further out. Then it shouldn't tip over without need for a counterweight.

But in all honesty, the best working designs ive seen here have a frame that goes over the load, with KAS or ports on the inside of the 'roof', therefor making a reasonably easy pickup, and it allows you to have your weight suspended below your centre of mass when unloaded.

Totally second that, it's the easiest design, and with the large wheels and the tank steering the fine-maneuvering for docking base parts is very easy.

[Brofessional]

It can help to use Quantum Struts to "lock" the cargo in place once you lift it, so it doesn't swing around.

[SkyRender]

The best counterweights are fuel tanks. Why? Because you can transfer fuel between them. A pair of half-full tanks on either end of a crane can handle huge loads and drive safely when not carrying loads just based on how the fuel is distributed. It can also handle variable load sizes with ease, since you can adjust your center of balance at any time to match your load. Just something to think about.

[leax256]

Seriously, try driving backwards

[SkyRender]

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[Loerelau]

For your delectation, I present to you: the Work Crane.

* Counterweight control via fuel transfer: make the back heavier as needed!

Why didn't I think of that. So smart!

[fcdrifter13]

Your lifting center needs to be behind the center of gravity.

This is my medium crane. it does most of my heavy lifting and the boom is moveable up and down to transfer weight forward and aft, the boom could be longer but the basic design does not allow for it.

And here it is holding the same thing off to the side showing the effects of the design, it can do this front rear side to side and does not transfer resources or have an ballast.

I believe on much larger cranes like the one I am having physics trouble with every time I test it without the boom need to be very well balanced because you are lifting much greater weight. I plan to lift 300tons with this one when its done.

It will use KAS winches on the back instead of a rotating couple so it will be smoother and helps ease the stress on the base.

[CleverClothe]

Seriously, try driving backwards

That won't work, he would just tip over when he accelerates.