Making Helicopters

[Sharkman Briton]

Hi, I'm trying to make good KAX helicopters, and I'm struggling with the manouvring, IRL I see heli's flying overhead all the time, all point where they're going and go pretty fast in that direction, when I try it in-game the heli just goes up, and only goes sideways if I point the orient the craft so the rotor points sideways.

Can anyone show or teach me how to make heli's move properly? (I put this thread in the SE because I wanted people to show off their KAX heli's and teach me how to make them work.)

Thanks!

Edited October 1, 2015 by DuoDex

[Hodo]

Really not sure if hey would work right in the current aerodynamic model. Not like real life anyway. I know in FAR they mostly work like real life but again not exactly right.

'Copters are rough to build because they are very tricky and subject to the most minor changes in fuel or load.

[Azimech]

That's the point with a helicopter, they move sideways because they adjust their lift vector. To go forward the swashplate changes blade angle at the rear, so blades moving past the rear quadrant have more lift. This tilts the rear up and the nose down. Once this happens, the lift of all blades isn't pointing directly upwards, but forwards. In real life this means less upwards thrust so the pilot has to compensate with more collective, all the blades get an increased blade angle otherwise the helicopter will drop in altitude. With KAX it's all simplified. Once you build a real helicopter, that's when the fun really begins.

[Mad Rocket Scientist]

Personally, I prefer to make fake gyrocopters, with a small propeller driving the craft forwards in addition to the main rotor.

[FlipNascar]

The easiest way to do it is to learn about why they work, because until you understand that and the basic principles of flight you'll just end up scratching your head and you may get something to work by luck. Y'know, like the leave a bunch of monkeys in a room with typewriters and eventually they'll write King Lear.

Threw in a quick google and this came up: http://www.explainthatstuff.com/helicopter.html

That might help you a little.

[Azimech]

I 100% agree with the above statement.

By the way, what am I going to do with all this paper over here?

[pTrevTrevs]

You may think that engines on a helicopter provide forward propulsion, but in reality all they do is turn the transmission for the rotors.

Of course, Sikorsky has been working on some BadS helicopters that use a pusher propeller and two counterrotating main rotors. Those things can get some speed​!

[Azimech]

Oh really, a coaxial design? Finally following their Russian buddies after all these years.

[pTrevTrevs]

Oh really, a coaxial design? Finally following their Russian buddies after all these years.

http://www.sikorsky.com/PublishingImages/News/raider_mountains.jpg

Sikorsky S-97 Raider.

Sikorsky is Russian! Well, he was, he moved to America to build helicopters.

[DuoDex]

I just put the CoM below the CoT, throw on a pair of tail rotors on the back and nose down. It's...fun.

EDIT : Post punted to Gameplay Questions.

[Sharkman Briton]

Thanks, DuoDex, but I don't think you're very happy with me seeing that your avatar isn't tipping it's hat to me XD

Speeking of counter-rotating propellors, the TU-95 Bear uses counter-rotating propellors to gain some crazy speed.

[Goddess Bhavani]

I have been building helicopters for some time.

I started with a tilt-nacelle design to experiment with hovering dynamics.

www.youtube.com/watch?v=9NCJimNdrfE

I then built a helicopter, without rotor articulation. Without rotor articulation it was nearly uncontrollable due to the centripetal force of tip jets whirling around at massive RPMs.

I then built a helicopter with rotor articulation.

I then built a ROFLcopter with rotor articulation and folding rotor system to push my helicopter 1337ness beyond the 21st Century limits (we stopped at the V-22 IRL for obvious reasons...)

I then built an OMG!copter to test the limits of KSP infernal robotics rotors. Any more dynamic forces and the game will literally, break. Unless you want to try building a Mil V-16 tri-rotor or larger

I then went back to tilt nacelles because it's the most effective high performance VTOL strategy in KSP currently - much more stable than IR rotors thus optimal when patients' (relative) safety is paramount.

Also, as a bonus for making it this far, here's a space helicopter. If Poland can into space, so can helicopter

As to how to control the rotary rocket- you kind of don't. The servo tabs magically keep it pointed the right direction as I think old FAR was smart enough to automatically make it act like a sort of cyclic system, while RCS, SAS, and gyroscopic force all contribute to overall omgbbq how does it fly factor.

Edited October 2, 2015 by pandoras kitten

[The_Rocketeer]

I have been building helicopters for some time.

I started with a tilt-nacelle design to experiment with hovering dynamics.

www.youtube.com/watch?v=9NCJimNdrfE

I then built a helicopter, without rotor articulation. Without rotor articulation it was nearly uncontrollable due to the centripetal force of tip jets whirling around at massive RPMs.

I then built a helicopter with rotor articulation.

I then built a ROFLcopter with rotor articulation and folding rotor system to push my helicopter 1337ness beyond the 21st Century limits (we stopped at the V-22 IRL for obvious reasons...)

I then built an OMG!copter to test the limits of KSP infernal robotics rotors. Any more dynamic forces and the game will literally, break. Unless you want to try building a Mil V-16 tri-rotor or larger

I then went back to tilt nacelles because it's the most effective high performance VTOL strategy in KSP currently - much more stable than IR rotors thus optimal when patients' (relative) safety is paramount.

http://i.imgur.com/Ybt8hnG.jpg

Also, as a bonus for making it this far, here's a space helicopter. If Poland can into space, so can helicopter

As to how to control the rotary rocket- you kind of don't. The servo tabs magically keep it pointed the right direction as I think old FAR was smart enough to automatically make it act like a sort of cyclic system, while RCS, SAS, and gyroscopic force all contribute to overall omgbbq how does it fly factor.

http://i.imgur.com/qPj86gZ.jpg

Show off... nah, just kidding, have some rep :kiss:

[Goddess Bhavani]

^ LOL Unfortunately yeah in hindsight that post is too helicopterflamyonantly showoffish.

I wanted to chart the evolution of various helicopter control and design methods in KSP tho - There are a lot of very strange and unexpected dynamic forces in rotary winged flight, even in KSP, that could take a new copter pilot by surprise. Even simple rules like "rotor disk directly above CoM" is not effective all the time because the rotor CoL in flight may not be directly over the shaft! (omg!)

I'm also not sure if KAX rotors allow for input of rotor trim, which is crucial for long flights; hence using Infernal Robotics as analog cyclic control for better precision.

It's all the tiny details that make real helicopters that much of an art to operate!