Why my helicopter is doing barrel rolls after the take off

[jackstech]

never in the past i try to do a project like this, cos im use it to do little jets or some ssto; are easy to pilot and make it

but a little choper even with the right pieces is extreme hard for me, cos i didnt know where the " points "(center of mass and the other 2) must be place

i donwloaded kax to get the rotors engines and make it; but sooner i take off and get some speed i lost the control of my craft; i try to compensate puting some juno engines to force to go straight but it make it worst the things,  

so ...HELP ( and sorry my english  if is confuse understand me )

 

 

 

 

[ARS]

Don't add jet engine. It makes your chopper even more uncontrollable. The rotor is what provides you thrust. In basic, the rotor must be placed directly on the center of mass. During takeoff, do not use full throttle, start slow, steadily raise your throttle until your chopper visibly lifting off. To move forward tilt your chopper slightly downward (slowly press W) so the rotor that provides lifting force can push your chopper forward. To move backward, tilt your chopper slightly upward (slowly press S) this will allow the rotor to "brake" your forward speed until it begin to push your chopper backward. Turn your chopper around with A or D before performing the same process to move forward or backward to change your heading. Adding jet engine makes your problem even more complicated since it means there's 2 source of thrust on your chopper that leads to different vector, making it more difficult to control. The main rotor is your lifting engine and your main engine

Note: to show center of mass, thrust and lift, there's 3 buttons on the lower left screen during the construction of your craft (near symmetry option) the center of mass is yellow-black sphere. Your rotor provides lift, but it can be used for thrust by tilting your chopper

Edited May 6, 2017 by ARS

[ARS]

Additional advice: I suggest you don't use the landing skids for your chopper. use landing gear instead. The thing is, it's very difficult to control your chopper to hover and then lower it to the ground slowly. Take note of how much throttle needed at minimum to lift your chopper, this can save you when you try to land. Landing can be done by slowing your chopper first until horizontal velocity becomes as low as possible before cutting of throttle (don't turn off the engine) when your vertical velocity start to drop, raise the throttle (don't forget to deploy your landing gear beforehand) if you think you are going down too fast, don't be shy to throttle higher until you regain some vertical velocity and your rate of descent begin slows down during which you can lower the throttle again (Repeat until you touch the ground, for small chopper, recommended safe landing speed is same like small aircraft (depend on your landing gear))

here's an example of chopper design (I'm using coaxial rotor because it makes the chopper looks like KA-50):

Note the position of center of thrust with center of mass

If you mastered how to control the basic chopper design, you can start making your tandem rotor chopper or VTOL chopper or even...

A quadrotor

Hope that helps

[jackstech]

take out the jet engines and manover in a "gentle way" solve the most of the problems. but now i have another question; there is a way to hoover  or know a mod that have a rotor that have that option?  and THX FOR THE HELP i been working 3 weeks without luck on this project !you save me

 

your second post with the adices give me a better ideas, thx again for the help you rocks !!!!!!!!

Edited May 6, 2017 by jackstech

[ARS]

There's a mod for controlling VTOL craft. it's called Throttle Controlled Avionics. It allows automatic balancing of VTOL craft. It also allows hovering control

from the spacedock description: "TCA is a plugin that enhances the attitude control of a ship by dynamically changing the output of its engines and RCS thrusters. Even with most unbalanced designs TCA maintains stable flight and quick precise response to user or autopilot input. TCA also provides many sophisticated autopilot programs based on this core functionality, including waypoint navigation and automatic landing. It is also fast enough to simultaneously control a whole squadron of ships without much overhead."

here's the link: https://spacedock.info/mod/198/Throttle Controlled Avionics