Hall Sensor Collective Stick

After some cajoling and encouragement from Talisman I have at last started to cut metal on my Hall sensor collective stick. The stick is an aluminium tube cut from a piece of TV aerial mast which is attached to a solid aluminium turned hub. An 8mm diameter shaft goes through the hub and will run in two brass bushes. On the end of the shaft closest to the seat will be a Hall sensor assembly and on the other end I plan to fit some kind of adjustable friction brake. My idea is to have a large knob to set the friction so that the stick will move smoothly but stay put when I let go. I also plan to make a box for the switches and hats etc. I have threaded the hub so that I can attach an adjustable counterweight on the aft end.

The cyclic works really well so I am hopeful that the collective will be equally good.

Oohhh i see a Westland Lynx cyclic grip. tasty. I also have one or two of those.

Im glad i could convince you to carry on. Its nice to see another builder, erm, building :)

Did you ever get to fly mine?

Yes, I did thanks. I liked the multi screen setup and the general feeling of being in a cockpit. Was it running on XP?

The grip is from a Gazelle I think, maybe the same as a Lynx, I could check at work.

Peter.

nice work ! and nice pics !

continue the good work !

I was still studying that problem of friction brake for cyclic and did not still achieved something satisfaying : protos were : too big, too strong, too soft, too light, never as it should be...

if you solved that one, could be very interesting to know about it !!!

protos were : too big, too strong, too soft, too light, never as it should be...

I know what you mean, I am not confident that my first idea will work, if I have any success I'll let you know.

More progress

A little more progress over the weekend, adding the drum for housing the Hall sensor magnets.

looking high quality. verry nice, simplified mechanics. how do you center or damp the collectiv input? i m verry curious on my side!)

keep it up

I am hoping that my brake will provide some damping, I am not planning on having any center. Hellfrog said he tried many designs to make a brake so I am expecting failure with my first idea :(

Peter - if your planning to fly the BS you will need to be able to determine the center of your cyclic.

I know its not realistic but if your not using FFB every time you trim you will lose your place and your flying will go all to hell. The same applies to pedels.

Basically, when you trim, you will need to bring the cyclic and the padels to the center point you had before trimming (on both methods of trimming) and in order to do this you need to know where that point was.

Using FFB the the new trimpoint is placed automatically, but it is not using a standard stick. Thus every time you re-trim, you will end up a little off and that can cause some serious problems. esp with rudders.

Now on any other helicopter, you can get away without a center point because the friction dampers on the cyclic will allow you to move it and then hold it in that new position, thus no need to trim or just a little amount of trim required.

However, since the autopilot and the hold functions get 90% of their information from the trim function on the KA-50 you will need to use the trim function. Every time you hit the trim button - the stab functions are updated with new heading - alt and bank information.

If you dont trim this wont be updated and you will end up flighting the autopilot all the time. Just try using autohover when the heading stab wants to be behind you.

I got around this by using detents, I have a very weak spring in my cyclic that allows me to feel the center point - but wont return it to that point by itself. The same goes for my rudders - they dont auto return either, but there is a very clear detent which you can feel as you pass the center position. Without these (as i found out) your flying will very quickly become very unstable.

Sorry,

Talisman

Hi Jamie,

my cyclic stick has a single vertical spring which brings it back to the centre position when it is released. There is no detent or damping, I find that having pressed the trim button I can usually move the stick by feel to near enough the neutral position within the time allowed. Quite often there is a small error which is removed by a second press of the trim button. I rarely need a third try. It's the same with the pedals, but in the case of the CH ones that I am using at the moment there is a centre detent which makes it easy. I may add dampers to the cyclic later but they are low on my priority list, i.e. well below populating my sticks with buttons, switches and hats etc. If I was clever like TriggerHapppy (which I am not) I could maybe add an electric motor to move the anchor point of my cyclic spring in the pitch sense.

I have been tied up with another project so havn't done any sim flying since last year, I am getting out of practice as they say. I am looking forward to getting this collective stick working so I can get flying again.

Best wishes,

Pete.

Hi Pete,

Just a suggestion on the centering of the of your inputs.

I was thinking of a spring loaded ball bearing and small machined slots (very fine) for a centre detent. Similar for the peddle inputs.

Not sure how it could tie into your setup - perhaps a sprung telescoping tube on the end of the cyclic assy. linked to a gymble connected to a horizontal travelling plate. The plate would have the sprung ball bearing recessed in the bottom and the slots machined into a bottom plate. There would need to be copious amounts of silicon grease to keep everything from binding up, but I suppose some Teflon sheet would do, too.

One quick question on the friction plates: what materials did you use? Neoprene or similar?

Cheers,

Marc

Marc,

Your idea sounds good for a detent device but I am not planning to incorporate one I am quite happy without.

The rubber disk is probably neoprene, it came in a pack of four from my local DIY store, They have a shiny coating and are intended for fitting to furniture as feet that slide on carpet. I thought that the rubber would provide some compliance, giving a progressive increase in friction as I tighten the brake. There will be some kind of stator plate that the disk will rub against, I may line that with some sort of fabric material. As you can probably tell it is all a bit experimental, we'll have to wait and see whether it works or not.

Are you building any cockpit hardware?

Pete.

So far I'm chasing up ideas and some tech in order to put a system together.

Whereas I don't have a CNC setup (yet!), I do have a small machine shop that I hope to use to fabricate some stuff soon.

I was going to start with the simplest, that being the pedals.

I've started turning some aluminium (or aluminum to our US friends :D) for the pedal bars.

I am a draftsman, so you'd think I'd be on the PC whipping up designs left right and centre...lol!

Any time I'm on the computer at home, I'm checking mail, posting here or probably playing BS!! ;)

Time to knuckle down and get stuck into it! And I have to thank you, and all the other pit builders here to inspire me.

Cheers.

Marc

Marc,

A machine shop! that sounds wonderful. NC routers seem to be a popular topic too these days among cockpit builders. The only fancy kit I have is my lathe, other than that it is hacksaws, drills, filing and elbow grease, it's like being an apprentice all over again.

Keep us posted if you make any progress with your pedals.

Best wishes,

Pete.

hehe! When I say machine shop, I mean a lathe and a mill. nothing fancy like CNC,although my mill is a convertible...

Once I break ground, I will let you know ;)

Progress update.

I have made some progress with an attachment bracket recently, 'still have to make the brake unit and fit a telescopic friction damper which I managed to obtain today.

I was hoping for success but expecting failure with my design of friction damping/brake. I wanted to be able to move the collective smoothly with light forces and have it stay put when I let go. I have just completed the unit and amazingly it seems to work exactly as planned. It is very progressive in its adjustment from too slack to too stiff and easy to set just how I like it. Time will tell whether it will continue to work or end up needing adjustment every two minutes.

The stick will now stay put at the kind of angle guaranteed to put a smile on any Black Shark pilot's face :smilewink:

Pete.

the Idea I had and wanted to test to modify my "à la" F16 cougar throttle... happy to see it works !!

nice done !

Awesome Pete :).

Thanks for your comments guys, Hellfrog & Astrospud. Good progress but a long way to go yet. I have to finish the Hall sensor assembly, mount the whole unit on the seat plinth, apply filler and paint etc. I am hoping to make a collective switch box that looks as similar as possible to the Black Shark one so I am looking for old joysticks that I can rob for the hat switches. Doing the wiring and SIOC will be a project for the winter evenings indoors. I am wondering what to use for the hand grip, a sheet of 2mm black neoprene sponge bonded to the tube is my favoured idea at the moment unless I can think of something better, the tube is 32mm dia. and I havn't been able to find anything cylindrical of the right diameter to slide over the end.

Has anyone tried anything like these for hat switches?

http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0516306

Any progress in the southern hemisphere with your pedals Astrospud?

Pete.

Minor, bought new CAD s/w called Alibre Design. Great little package for USD$99 with similar modelling capacity to Inventor. Getting my head around it.

It's winter here atm, so waiting for the weather to warm up a bit (a bit cold in the garage!)

Hi Marc,

CAD? I really ought to use CAD at home but as you can see I am a pencil and paper user. My employer very kindly gave me a week of training on CATIA about five years ago, but since I don't use it and am a few years into my second half century anything I learned has completely gone.

A week off work and trying to make the best of the warm weather in my garage before we head into winter (girlfriend is not impressed!).

Attached pics are todays efforts making more fiddly bits for the sensor assembly. I have to thank Mike Powell over on MyCockpit.org/mikesflightdeck.com for the basic design.

Pete.

Hey Pete, whatever works. :)

Paper and pencil is great for fleshing out concepts really quick. as I can see from your drawing, it's easy to follow. Can't imagine not being able to work from it.

I go CAD because it's what I do (CAD Monkey) and my pencil/paper skills are really quite bad :P

Update 05SEP10

The friction unit is not perfect. Over time and after some use the friction reduces, I don't know why it is time related but use is certainly causing some wear of the stator plate which is made from soft aluminium sheet. I shall probably substitute a steel plate for the aluminium one. I shall also investigate whether I can obtain some PTFE sheet (maybe 5mm thick) and some rubber so that I can make up my own friction pads.

Otherwise, I have reached a point where the unit is almost complete structurally. Next will be paint, counterbalance mass and then onto the wiring. I will probably have to take a break for a few weeks because unfortunately another non-flightsim project needs my attention.

Bye for now,

Pete.

Update 05SEP10

 

The friction unit is not perfect. Over time and after some use the friction reduces, I don't know why it is time related but use is certainly causing some wear of the stator plate which is made from soft aluminium sheet. I shall probably substitute a steel plate for the aluminium one. I shall also investigate whether I can obtain some PTFE sheet (maybe 5mm thick) and some rubber so that I can make up my own friction pads.

 

Instead of searching for PTFE sheet, why not just cut the centre out of a Wilton cookie sheet? It's not 5mil, but it might work.

Great looking project BTW