Showroom 6DOF Stewart AC Servo Motion Helicopter Build

Good idea, I'll poke some ratios into my spreadsheet to peruse. I'm not going to change anything yet, till I've tried existing, but it's a good option. Thank you.

"No need for Bass..." too late, it's already on my pile of bits to fit. I didn't like the idea of the gearboxes trying to create high frequency vibes. It's an awful waste of precision engineered gears.

So....my four pulleys turned up and I was dissappointed, at the weight of the box. So the concept I'm going to apply is that I'll turn all the hello parts into something resembling swiss cheese.



In that I make holes in every part that I can, as long as it doesn't detract from the visual look of the helo. The pulleys for instance can be both hollowed out by dishing both sides and then create holes through the web that is left, that should by my reckoning, reduce each pulleys weight by half, after all it's not like they have a great load on them.

I thought I'd have a good week this week, but ending up going back to the drawing board, because the models I bought for the 100 tooth pulleys were somewhat larger than the ones in my model. Maybe it'll have something to do with the fact that I changed from 3M to 5M when purchasing, but not updating my models.

So I had a fair bit of tweaking and redrawing to get back on track.

My efforts to date include making the spigots to go in the cyclic main shaft and machining the pulleys.
My chuck jaws were unable to hold the pulleys without some modification.
So...after offering one up to the chuck, decided to do the following.




Cut some extension bars..


Remove and prep the existing soft jaws.



Weld the extension pieces on...


After putting them back in the chuck, set about machining them to run concentrically..
but needed a tool that I didn't have to do too much grinding to..


Also the jaws will flop about if I don't restrain them with a makeshift ring, and tighten the jaws onto it.


Also I undercut the jaws to ensure that I only clamped onto the toothed part of the pulley and as the clamping part is the same diameter as the pulley and wide enough to extend across several teeth, there is not damage to the teeth.


So far I have the weight down fom 1394 grams to 978 grams , and have worked out I can get 8 x 22mm diameter holes in the web area, so should be well under half the original weight.





I would have folded all the radiused side panels, but our CNC folder at work is undergoing some maintenance, so I'll have to wait.

I usually just put 3 dowel pins onto the teeth and clamp them in a standard chuck with the jaws reversed. This centers the pulley perfectly (as long as the number of teeth is divisible by 3) and avoids damaring the flange rim.

Great idea, will do that for the smaller pulleys.
IMO the bigger pulleys needed something more solid due to the forces put on the pulley when plunging the radiused tool in when dishing out the sides. I didn't want to risk any damage/distortion, as they took forever to get here, and are quite expensive for what they are.

Pulleys all drilled, didn't actually make less than half original weight, but the reduction is acceptable.


Onto the pedal assembly now, and this isn't going to be a five minute job, but hey...

Pedal assembly drawing.
Haven't actually got the material in solid form, and want to utilise the material Ive had knocking around for years. So..

Will have to make it in sections..

This gives me the lower part, with the top added after...


I want all the holes in the lower part to be concentric, so thats where my thoughts are now, so will probably drill after welding. I only have a small bench drill and a lathe, so...mmm