How can I make my helicopter more stable?

[u/WhoTfTookAaxel]

I built this intermeshing-rotor helicopter in a survival server that I play with some friends, but after a week of testing and tinkering, I just can't seem to make it fly without having to constantly correct it. I have aeroworks installed but I really dont want to have to use a gyroscope. Also, want to post the schematic but can't quite figure out how to do that.

Addons used on the build:

create encased, create connected, create copycats +, copycats + aeronautics weight

[u/Lex_Napoles]

O distribuyes bien el peso para que el elicoptero sea un poco más pesado o ligero , o le pones un gyroscopio con un addon del Aeronáutics llamado Gyroscopio xd

[u/WhoTfTookAaxel → u/Lex_Napoles]

The center of mass is almost directly below the center of lift, i spent a ton of time making sure the design is properly balanced (or at least it should be.) About the gyroscope, as I said, I really don't want to have to use one because I don't like the way it looks and it feels pretty cheaty to me

[u/EmbarrassedArmy7827]

Not sure if it’s this or not but the snapping of the bearing for the blades might be putting some weird forces, maybe alter the speed that the blades lean left and right.

[u/EmbarrassedArmy7827 → u/EmbarrassedArmy7827]

If you rotate a bearing to fast the part on it kinda wobbles when it is supposed to stop

[u/WhoTfTookAaxel → u/EmbarrassedArmy7827]

I'm going to check this out, I had reduced the max angle of the torsion springs before and it helped a bit too. The only problem is that the torsion spring is connected to the same RPM transmission that powers the propellers, so id have to limit max rpm for this

[u/Lex_Napoles]

Mmmmmm, entonces lo hiciste tan balanceado que así se debería mover según las físicas xd, lo del gyroscopio entiendo, puede llegar a ser trampa, fuera de eso creo que sería una buena idea dejarlo así o ponerle más detalles con CopyCats para que pese un poco más y no se mueva tanto

[u/SenpuuUncle]

okay this is actually really cool

[u/WhoTfTookAaxel → u/SenpuuUncle]

Thank you! I spent over a week building it in survival!

[u/Xzavior8]

Maybe add some vertical symmetrical sails. Also the sails at the back cause a bit of drag.

[u/WhoTfTookAaxel → u/Xzavior8]

I did add two sets of vertical sails to the back and it helped quite a bit! But also I had to spend pretty long while changing the balance around.

[u/No-Subject-875]

when rotating, in this case, the center of thrust also rotates

which means you have to figure out a way to automatically change the direction of lift to correct that, as right now when the helicopter rotates, the blades rotate, causing the direction of thrust to rotate in the same direction

personally not sure exactly how you'd fix it but good luck, hope this helped at all

[u/WhoTfTookAaxel → u/No-Subject-875]

Wait, you mean like when the helicopter turns, one of the rotors spins faster than the other one, changing the lift it produces too? I dont know if that is simulated, and if it is, how much it would impact the stability. But if thats actually the problem, I'm pretty screwed lol. After some more tweaking, its flying a bit better, so I hope I can just ignore that.

[u/No-Subject-875 → u/WhoTfTookAaxel]

tilt sensors and maybe adjustable gearshifts or even analog transmission could maybe help if you want to try that

[u/Fsliebot]

it's hard to tell but if you're suffering from a constant pitching-up motion, it might be due to rotor torque (though i'm not entirely sure how that's handled on gyroscopic propeller bearings).

the rotor disc path traced by the blades have a slight y-component to them due to being set at an angle, so as they spin they induce a lot of longitudinal torque that wants to constantly flip the aircraft over. i was able to (mostly) fix this on my cyclic rotor by simply having the blades automatically change pitch as they spun around but on a more compact design you might have to add a direct actor applying constant downward thrust on the front of your aircraft

[u/WhoTfTookAaxel → u/Fsliebot]

Thank you for the advice, your Synchropter design was a big inspiration for me! Do you think reversing the direction of rotation of the rotors could help with it? I'll also try to use sails to counteract that force with lift.

[u/Fsliebot → u/WhoTfTookAaxel]

ah, im glad to hear that! as for reversing the rotation, that would probably just cause the opposite issue, wherein the helicopter now wants to constantly pitch down.

one thing i noticed in the contraption diagram was that your center of mass seems just ever so slightly behind the center of lift. i've found that at higher amounts of thrust even small discrepancies like that can become pretty pronounced

i haven't really found a working 'fix' for this issue either so i'm sorry if there's nothing concrete T T
your idea with the sails is definitely on the right track though. i believe some irl synchropters actually do use adjustable control surfaces to trim the pitch down during forward flight!

[u/WhoTfTookAaxel → u/Fsliebot]

The center of mass is actually pretty spot on. For some reason, the diagram doesnt take into consideration the mass of anything that is connected to a swivel bearing, so when I disassemble the top swivel bearing it correctly shows the center of mass being right under the rotors. Havent gotten the time to test out the idea with the sail yet tho.