Well, since I'm new to this game , I want to ask you guys how to create a drop crate that can act as a crab (meaning: storing actors, moving around and get sucked by dropships, while saving the actors inside)? Thanks for reading and sorry for my english.

That would be nigh on impossible and incredibly complex.

I feel as though this has been discussed. I'm assuming (though I can't recall) that one couldn't merely pin a drop crate to an ACrab as an attachable.

That wouldn't work at all.

Unsurprising. Pity, of course; that would be hilarious.

Come to think of it, I believe I've seen something like this....

EDIT: Ah ha, found it. It's not quite what you're looking for, and whatever the idea was, it sure as hell didn't work, but it's a start. Look up "Legion of the Resurrected." Should also be in the Mod Contest themed "Undead;" think that was MC5.

Then what about that walking dropship that could fly and store cargo?

It couldn't be picked up inside other dropships, which is what the OP wants.

There was this ♥♥♥♥♥♥♥ mod that involved pilotable dreadnoughts and drop crates.
I think it involved the dreadnought being useless until someone gets into it... or rather get sparkle LUAed into the drop crate... in the dreadnought's inventory, or some ♥♥♥♥ assery.

The pilotable things were based around just stuffing the actor off in the very corner of the map where collisions are turned off, if I remember correctly.

I believe the apollo shuttle of Areku made that...
you should PM him, he always have a surprise!

I would think it would be ACrab like craft.

If you mean what I think you mean, then no, that wouldn't work.

riiiiiiggghhhttt... So it seems like my idea can't be done. But what should I do if I just want to make a walkable, jetpack-installed crate? (pretty much the same idea, minus the craft-in-craft part).

That would probably be quite a bit easier, though still requiring quite a bit of Lua expertise if you don't want oddness and you want polish.