Helicopter Problems

[T-Pilot395]

Helloo KSP!

Anyway here's my problem.

I'm trying to make a basic helicopter for kerbin lulz.

Problem is, the heli keeps tipping forward or backward. If I up the throttle slowly the whole thing will fall over on its side too. This happens on takeoff.

My center of thrust is slightly higher than the center of mass, but both are in the same position. I have 2 standard canards at the back to help with maneuvers.

My current setup looks like this:

...––ââ€Â³Ã¢â‚¬â€œÃ¢â‚¬â€œ

â—…â—Â▤▋▤►

...â—¯....â—¯

â—…â—Â: Tail Connector with 2 standard canards.

â–¤: Mk1 Jet Fuselage (Fuel Tank)

â–‹: Fl-025 default RCS Tank (it dosen't provide fuel crossfeed does it?)

â–º: Mk1 Cockpit

â—¯: Landing Gear

. : Empty space

2 Fuel lines run to the rotors from the main fuel tanks. The RCS is to prevent crossfeed so both tanks feed to the rotors at the same time.

I'm stuck with the design for now. Anything I can do to make a stable chopper?

[AlexL]

I tried something like this a while back

http://kerbalspaceprogram.com/forum/showthread.php/14212-Stock-Helicopter

Maybe you'll find something useful in there. An actual image, or link to an image, of what you have would be useful to help us help you, but really long wings seemed to work well back in 0.15

[EndlessWaves]

Which method are you using? Bendy pylons to make a seperate rotor or rotating the entire vehicle?

[kamilDrakari]

Press F1 to take a screenshot, that will help a lot more than your little ASCII art especially since you didn't tell us what the helicopter part is made of or how you plan to spin it.

[Elios]

first your controls will be 90deg out of phase

2nd does KSP model torque? if so youll need a tail rotor for yaw

but helis hard to fly in the first place might need an SAS to heli with heading hold

i fly RC helis btw

let me know if any of that helps but screen shots would help also the ship file and what mods your using

[colmo]

Maybe he's using the Damned Aerospace blades? Remove the canards - built right, a helicopter can manoeuvre using only torque.

I think the design is too long - two and a half fuselage sections plus a tail connector. Centralise your mass. I'm also not convinced the CoM and CoT indicators work precisely for helicopters - I find the CoM needs to be 3/4 of the ball in front of CoT.

[T-Pilot395]

Sorry, forgot to mention I'm using Damned Aerospace.

I'll get a screenshot of it tomorrow morning. It's late here.

[colmo]

Here's what I was talking about regarding Centres of Lift and Mass - this helicopter is perfectly balanced:

[T-Pilot395]

Here's what I was talking about regarding Centres of Lift and Mass - this helicopter is perfectly balanced:

OMG SO that's how you do it??

Mine had it's COT right smack on top of the COM.

I'll post results when I modify my chopper.

EDIT: It works! Now I must remember to put the COT NEAR the COM, not on top of it!

[ATTACH=CONFIG]34377[/ATTACH]

Edited October 7, 2012 by T-Pilot395

[colmo]

Result!

I'm wondering if it's something to do with the tilt a helicopter requires when flying forwards - due to the incline, the thrust is moved more forward relative to the mass. If we build a helicopter with CoT bang on top of CoM, and attempt to fly forward, it just tips over as the thrust is not aligned with the mass.

[T-Pilot395]

Result!

I'm wondering if it's something to do with the tilt a helicopter requires when flying forwards - due to the incline, the thrust is moved more forward relative to the mass. If we build a helicopter with CoT bang on top of CoM, and attempt to fly forward, it just tips over as the thrust is not aligned with the mass.

I think so. Being a flight sim enthusiast I found helicopters in X-Plane and Flight Simulator X tend to tilt forward.