Build centrifugal clutch for Cox engine myself?

Even though I have never examined COX`s car set-ups closely, I do have an old cox car from years back but I don`t think it used a Centrifugal clutch if I recall, perhaps the newer COX cars like the GTP Nissan did.

The clutch can be a rather simple looking idea butr don`t forget to keep it balanced. Lite Machines heli`s used a very effective yet very simplistic looking design.
I can`t scan in their parts schematic to show on here but maybe you can find it on the net somewheres

Here are some pictures of my spare GTP Nissan engine. The clutch bell is held on by an E clip. The nylon clutch shoes are held on by roll pins in the zip starter housing. There is a simple wire spring that holds the clutch shoes in at idle. There is a flywheel on the engine but it will wind to a high RPM without a load.

I will try to get a pic of the parts schematic and upload it tomorrow if I can;its basically a 2 piece/part design,not really that difficult to make but a little experimenting would be required to taylor it to your desired rm enagement point

Thanks all for answer.
So. Do you have an Idea how can I build it?
I think the clutch bell is not realy a problem. I think i can produce it on my lathe.
But how can I make the bake clutch?

Mfg
bnitram

You might try adapting a centrifugal clutch from a small chain saw or at least studying one to see how it is contructed.

SuperDave

Scale is the big problem.

The plastic shoes are probably circular with a section sawn out. Drilling operations probably should be done prior to parting from the parent stock. OR if a flat wafer is used the drilling is done first to hold onto a lathe jig.

There is likely relief on one end so the pivot allows the shoe to become entirely clear of the clutch bell.

I suspect a high density plastic like cutting board or UHMW polyethelyne is suitable. Cutting board is quite brittle though.

Phil

Hi all,
Has anyone done such a thing before?

Mfg
bnitram

bnitram wrote:Thanks all for answer.
So. Do you have an Idea how can I build it?
I think the clutch bell is not realy a problem. I think i can produce it on my lathe.
But how can I make the bake clutch?

Mfg
bnitram

The LMH clutch is a simpler looking clutch than the cox and would be possible to make on a lathe but I also reccomend a dremel and drillpress to make it a more precise piece, you may be able to fimd it on the lite machines site

Hello,
thanks for answer.

What do you mean with "LMH clutch".
I dont no what kind it is.


bnitram

Lite Machines Helicopter = LMH

They were big in the 90's with Cox and then Norvel powered RC helicopters but were hampered by manufacturing difficulities with a new CNC machine that was purchased. Caused them to go under. The show up on ebay and RC Groups for sale now and then.

Jason

Hello,
Do you mean such this clutch?
http://www.helioldie.de/mueller_alouette/alouette_pitch/alouette_kupplung.JPG


bnitram

at clutch is similar to the LMH but not quite the same but you are on the right track. I hope these pics help out.

So there is the basic parts run down. An extended "prop shaft/prop screw" 1 inner clucht piece,1 outer piece w/gear and 1 starter hub. I`m assuming the outer clutch piece is made of delrin or some other very wear resistant material because the inner clutch is pretty good aluminum and shows more wear than the outer clutch piece does. the slots in the inner piece determine engagement point so that is your fucus on timkering to get your set-up right

Thanks for the pictures!
I have to look how i will make it.....


bnitram

A lathe,dremel and a drill press is about all you need to make these really. could all be done on a drill press if you have real talent or a mule`s stubbornness combined with a saints patience.
I could tear it back apart for measurements if you really need. I havn`t looked closely at the COX clutch but I bet its a bit more complex ergo, not as much "fun" to reproduce but perhaps it would be much simpler to buy one(cox) I don`t think I have a spare LMH clutch.
As I said or should I say tried to but the pics kept jumping between the text, (next time I will post pics and add text after) the clutch pic you showed is similar, appears to be "deeper " but may be better for a higher drag /friction situation such as turning tires;more resistance perhaps that heli rotor blades.

Hello,
i do not know if this kind of clutch is really easy to finished rebuild..... The material has to be the right so that it couple at the correct speed.
Aluminum is not the same as aluminum.

Martin

I would immagine you could contact LiteMachines for those details, the aluminum is rather high grade based on the resistance to wear, aircraft grade at minimum, (yes I know there are multiple grades) and the Delrin is an assumption as well. I havn`t read through the literature on mine since 1997/8 when I built mine. But I believe LiteMachines is still in business for defense dept military UAV contracts etc. There may be listings on other forums for the heli`s, I never got into the heli forums.
I got the lmh because I couldn`t fly my planes at my house without destroying them in the tight quarters;ditto for the LMH and then I heard of clancy aviation in Flying models magazine. I was so skeptical I bought his video before committing to building any of his bee`s but after watching his video it was plain to see that his bee was for me but I needed a few training flights with the teedee020 powered littlest stick to up my game of rusty thumbs from hovering back to it wont slow down lol
Lets just say Andy Clancy makes flying the lazybee in an alleyway,from take off through full flight duration to landing in the alleyway,with a non throttled COX BlackWidow049 really smooth and easy.
Now back in the day with my COX TeeDee 049 on an ace wizzard I could fly figure 8`s through 5 lines of the high voltage high wire powerlines running across our field until the wings folded from too many G`s but not these days.

Most grades of aluminum have the same modulus of elasticity, so geometry is more important.

If different materials are run against each other, assuming they don't crayon onto each other, there will be less galling than if the same alloy of a metal is run against each other.

Phil