Need help with a chinook style heli

[KapitalismKarl]

I cant figure out how to setup the rotors/gyro so that I have yaw control without having a tail rotor.
I prefer having yaw control without placing the rotors on pivots, but if I must I vill.

[Kopfman_2731]

Setup an Add-block for each of the rotors. Input A will be Stabilised Roll in both cases.
Input B will be Stabilised Yaw for the front rotor and inverted(Stabilised Yaw) for back rotor. Now connect the Add-block outputs to the Roll input of their corresponding rotors. Violá!

[KapitalismKarl]

That worked 100%! Thanks

[Stealth17]

Hey,

Sorry to revive this old thread, but I just don't understand how to do it.

I have this setup:

2 rotors
1 gyro
1 engine

1 ADD block
Input A: Stabilized roll output from the gyro
Input B: ??? I can have either stabilized yaw from front, or inverted yaw from rear, but not both.

Do I need to add another ADD block?

[Kopfman_2731]

You need one ADD block PER ROTOR (two in total). I think you missed that.

[Stealth17]

Thanks for your reply :)

I got that part, but I wasn't clear on how to interpret the other connections now. Got my helo working now :)

[Anwaan]

I would have never figured that out. I'm still not following how it actually works. I get how to set it up, but not WHY it works. Is it just a game thing or is that actually a simplistic representative of how a chinook actually works? I'm rather intrgued by this now...

[Kopfman_2731]

@Stealth17: Sorry for the unhelpful reply, glad you figured it out on your own.

@metl:
Look at it this way: Yaw makes the vehicle turn on the spot. But with two main rotors (and no tail rotor) there is no input-node for yaw, only roll and pitch.

We can work around that and achieve yawing, by making one rotor roll one way and the other rotor roll the other way (hence the inversion) at the same time. This causes the vehicle to turn on the spot.

So we connect yaw control (from cockpit seat) to the roll-node on the front rotor, and the inverted yaw control to the roll-node of the back rotor.

We now have yaw control, but no roll control. So we use an ADD block for each rotor to add the regular roll control signal to the yaw signal and connect it all the the roll-nodes. And BAM: full control xD

I hope this helps.

[Anwaan]

It's certainly fascinating. I built a chinook with a tail rotor a while back. I think it's time for a refit!

[Kopfman_2731]

To be perfectly honest: I do not really understand WHY it works. I think rolling to both sides at once should actually cancel out. But I tried it out and (thankfully!) it works xD

[nizzemancer]

Basicly when you turn right, it tips the front rotor down to the right side of your helicopter and the back rotor tip down on the left side,

[Kopfman_2731]

Yes, exactly. This is even how it works in real life. But my mind cannot comprehend why these two forces translate into a yawing motion, instead of simply canceling each other out!

Edit: after carefully rereading your answer I actually understand it! Thank you! I just found it difficult, because the rotors in SW do not actually tip in any direction.

[No_Face]

A big thank you, thanks to you, my chinook finally turns (I had hidden two small ducted fan in the helicopter but it was not ideal (it turned too hard, I had little control over )). Now it's much better. I'll finally be able to work on it again, I'd put it aside for too long . Now I have to solve other problems

(I also earn my emoticons)


By cons, my English is bad, I'm not sure I really understood your explanations. Your explanations seem to say that the input A goes to the roll and the input B to the yaw.

While I have an entire ADD block (input A and B) that goes to the roll and another ADD block that goes to the yaw. The two input of an ADD block are therefore identical.

The output of my 1st ADD block goes to the roll of the front rotor and the output of the 2nd ADD block to the roll of the back rotor.

I do not know if that's the right thing but it works anyway.

[nizzemancer]

I’m just guessing here but I don’t think you actually need to do this anymore since you can (at least now) change the directions of the rotors and such in build with the u i and o keys to invert their position in different directions, not sure about how it was the time of the OP.

[JSF Havoc]

Kopfman, I would really like to see a diagram of how you have it set up. Seems like even if I set it up like I think you have it, it wants to roll into lawn mower mode even with stabilizer on. And still no yaw control.

[Trav]

Originally posted by Kopfman_2731:

Yes, exactly. This is even how it works in real life. But my mind cannot comprehend why these two forces translate into a yawing motion, instead of simply canceling each other out!

Edit: after carefully rereading your answer I actually understand it! Thank you! I just found it difficult, because the rotors in SW do not actually tip in any direction.

Glad you understood this. To add to it a bit more if you haven't already done some digging.. the same concepts are used on RC heli's too, try looking at a few in your local RC store!

There are two ways to achieve this (correct me if I make any errors)..

an old method would physically angle the rotors in a direction to achieve lift in a particular direction. However the more modern method is with "Swash plates". where the blades are connected to this plate which changes angles depending on inputs. EG a left roll tilts the right side of the plate DOWN, pulling the right blade down for steeper angle, more lift. As the blades rotate, they follow the motion of the swash plate, angling appropriately (collective changes). on the left side, less collective. on the right side, more collective, forcing the vehicle to tilt.

Collective input obviously then, raises or lowers the entire swash plate synchronously.

I always found these mechanics quite fasinating!