How does one build a halfway decent helicopter?

[Lonesome 77]

I've had the Firespitter mod and KAX for a little while now, and of course they add parts for making a helicopter. I was looking at the Firespitter manual/guide and it said to make sure that the center of lift is going through the center of the center of mass ball. So I did this with all my helicopter attempts, and each time my helicopter either shoots upwards pretty much uncontrollably, or goes up alright for a second and then flies backwards on its rear end and crashes; today I thought I had something going when it went up and forwards for a bit, appearing to respond to my controls, but then went up, flipped to its back, and nose dived into the ground.

That was with firespitter, I had the helicopter cockpit, passenger compartment, and then a round-to-oblong adapter, the green biplane tail (kinda like the look of it on there), and the tweakable helo prop on top with an air intake. Skids on the bottom and i was experimenting with tail rotors. At one point when my helicopter was flying wonky I put on hover and it stabilized it but it would move and such quite slowly.

I would post a screenshot but I don't think I got any of it.

[Flame 2512]

Is it that fuel is being burnt and moving the centre of mass, if not that then just try looking at the stock craft and figuring out how they work.

[maestro]

Huh, well here's a old pic I did of a heli that recoverd command modules. I'm not sure I could even do it with the new flight model.
http://steamcommunity.com/sharedfiles/filedetails/?id=222029006

Otherwise, best advice I can give is the center of mass for a heli is extremely sensitive. Just a little bit in the wrong way and it won't be controllable. Note that my only fuel tanks in that picture are located directly under the rotor, where the center of mass was. Carrying a pod on one side was a bad idea but afterwards I put the winch on the bottom and it worked.

[Lonesome 77]

That looks very much like the one I tried to make, minus the floats and that tail rotor.

[maestro]

Originally posted by Vikingr:

That looks very much like the one I tried to make, minus the floats and that tail rotor.

Gotta have a tail rotor of some kind for stability, it can be 2 side rotors, or one back one but have to have something. Keeping it simple worked best for me with helis.

Also remember you need to assign number key to toggle hover mode. Hover mode lets you be much more stable for when you take off and land. There's also up/down increments you should set to number keys. You need those when in hover mode. By using the up/down increments plus throttle adjustments, you should be able to land fairly smooth.

One last thing I can say is just test out any design to see how well it hovers in one spot first, before you try anything else fancy.