Chopper Time - DIY Helicopter Collective

Aerofly FS2 has just added an awesome R22 helicopter. What a challenge this is to fly and I can see I urgently need a good quality collective to get the hang of it !

I really like the look of Blugreen's design (Scroll down past the actuators)
https://www.xsimulator.net/community/threads/linear-actuator-build-yes-another-one.9419/

Placement of pots and belts all seems straightforward. Does anyone have any ideas where to obtain a suitable grip that would rotate on the metal shaft?

UPDATE: 22mm stainless steel tubing is easy and fits standard mountain bike grips, but the grip will errr grip! How can I get it to rotate? Join two pieces of pipe maybe with an inner shaft?

22.2mm tube with 1.2mm wall gives inner diameter of 19.8mm so i could put 1 19.05 tube inside t.

OK this should take care of the handle and throttle but how do I get some nice friction and resistance to turn?

OK more bits ordered.

Gas stay for pulling resistance:
https://www.ebay.co.uk/itm/GAS-STRU...0NM/201080472295?_trksid=p2485497.m4902.l9144

This will do to make it hinge:
https://www.ebay.co.uk/itm/Boat-Yac...are/232937078213?_trksid=p2485497.m4902.l9144

Just need a couple of gears now to link in the 2nd pot.

OK, here's the idea for the lever side of things. I just need to work out how to do the gears. I've never bought gears before so will have to work out what those specs mean: pitch etc, I'm thinking a 3:1 ratio should be right to convert about 45 degrees of rotation into 135 degrees on the pot. The gear attached to the lever will need a bore of around 8mm though and the pot is say 5mm? So I need gears to fit these and mesh.

Since the very first version of my first rig I use gears for connecting the pots with the motor axis.
I use „module 1“ steel gears. They have a 6mm hole that can easily be widened with a metal drill, and they have 2 tiny screws for fixing the gear to the axis.
These tiny screws will still hold after widening the hole to 8mm.
For my motor axis I had to widen the hole to 12mm, and in this case I simply used two nuts for fixing the gear to the axis.
Module 1 steel gears are available in a large variety of sizes, so that you will surely find the ratio you need.
You will surely find some pictures in my build thread. (I am on my mobile phone at the moment, and pasting pictures is a bit cumbersome with this device.)

Fantastic @MarkusB . Thank you. The last piece that I am wracking my brain about is how to achieve a spring resistance to rotation of the grip. A normal tension spring would provide resistance to twisting but how to fix it to one tube inside another, especially with a pot rotating and attached to the inner tube. Any ideas cone to mind?

This looks perfect. 3:1 and choose the bore diameter. Its going to be a seriously engineered bit of kit this. I'd thought the gears would be plastic at first.

https://www.ebay.co.uk/itm/1-Module...hash=item3d298d290e:m:mUqF34MCfxoAmsg5ssDUWfA

The spring you want to add to the collective is just for applying friction to the grip, while it is not meant for letting the grip snap back into its original position, right? (At least in my understanding it does not make sense to let the grip snap back, because twisting the grip is for adjusting the thrust you give to the main motor.)

If this assumption is true, what about the following idea:
You make the outer tube a bit longer than the grip. Then you mount a little steel band to the outside of the inner tube with 2 screws. One edge of the steel band touches the overlapping part of the outer tube. When tightening the screws, the steel band applies pressure to the outer tube and presses it against the inner tube, which increases the friction. In this way you should be able to adjust the friction quite easily. See the following scetch for illustration.

Nice idea thanks. Especially useful though is the clarification of how the twist action should work. Yes I was thinking it should snap back like a motorbike throttle. However I have also just learned that it is not the throttle but the governor and now you have explained that I only need some friction it all becomes a lot easier. Many thanks again!

Hi again,
I also lerned about all the helicopter controls just today, so thank you for bringing this up. I will definitely try this Aerofly helicopter.
By the way: I learned some basics from the following video:


About the collective again:
Moving the collective up/down increases/decreases the helicopter's altitude by collectively changing the pitch of all rotor blades (see minute 5:45 in the video). This does also already change the throttle.

Twisting the grip allows you to manually fine-control the throttle (see minute 10:55).

The governor in turn is an electronic device that automatically fine-regulates the throttle depending on the current RPM value (see minute 11:30). The governor can be turned on/off with a little switch at the end of the collective. During flight it is usually turned on, so that you don't need to manually twist the grip at all.
For that reason, I am not sure if this grip-based manual throttle control is such important for a simulator at all.
By the way: When the governor is on, the grip automatically rotates under your hand, which would be the next challenge for your build.

I wish I'd watched that video before designing this collective. I don't need a gas strut, just some friction on the lever. I don't even think I'll even bother with the twist grip at the moment. I'll be flying with the governor on so I'll let it control the throttle. I still want to make this collective, but now I'm not simultaneously trying to control throttle and collective its a bit less necessary than i thought- just continue mapping one of the sticks on the quadrant to collective and its enough. I now think fine control of the cyclic & rudder is the key to good flying. I'd thought precise use of the collective & throttle was crucial. Now I need to look at my cyclic - I'm mapping my ACE yoke, but this ACE is a bit tight on the springs (B737 model) and I think I'm going to make myself a nice center column flight stick after I finish the quick version of this collective.

@MarkusB - I just got sent this video showing an alternative approach to the friction. Just put the right grease between inner and outer shaft.

Phase 1 complete - twist throttle to come later

I dumped the gas strut. No need as there was nice friction from the clamp. In fact the whole thing feels very rugged. Everything else was pretty much as planned. The twist throttle should work as planned too, with pot held at the opposite end to the grip.... if I ever bother adding it.

The throttle
OK, I think this will work for adding the twist throttle.


Edit: better if I move the screw and slot to the other side of the clamp to avoid a pointed weakness

Better get rid of pots. And put halls.

You persuaded me. I've been on the hall effect learning curve since your post. I finally tested it today.

* 5mm cube neodynium
* Allegro A1324LUA-T - mV/G
* Magnet is about 1.5mm from sensor

The trouble is that with a rotation range on my device of only about 50 degrees I can only get around 0.8 volts variation between max and min and when I put it through the Leo Bodnar I get output values between 1431 and 1496. Using this in a game it isn't precise enough and is quite jittery.

Help please! Do I need to:

1) Get stronger magnets
2) Put the magnets closer
3) Get a more powerful sensor
4) Orientate the magnets differently to get more range - I played around with putting them into the holder I 3d printed in different ways
5) Gear up the mechanism to get more than 50 degrees rotation.

Thanks !

UPDATE: I've been Googling. Was I placing the magnet towards the wrong face? I was holding it close to face A. Is the end B better?

Spit40 that's great. U can use two neodymium magnet, like that for better range.



Then gear reduction, as well too, if that will be not enough. And to spring the gear to eleminate the slack.
Set up the range in dxtweak.

Great thanks. 2 magnets won't work with my design but i can see my issue was that i was 90 degrees out with how the magnetic field needed to act on the sensor. I've actually switched to a flight stick design in order to try out my first hall sensor device. You can see the magnet in the centre of the gimbal rod and the slot to the left holds a sensor bracket to position the hall directly over the magnet with 1mm gap.

Try what goes right for your desighn. Sensors are a bit of several different kinds for magnets positioning.

Thanks ! My new sensor holder is working great. I'm getting a nice voltage range across about 60 degrees of rotation