I guess I ought to post a picture of my newest watch gear gearbox in here.
And the plane that I put it on.

I finally figured out how to get closeups with the new camera.

Video of the plane flying in the living room
http://www.rcgroups.com/gallery/show...cat=500&page=1

The thrust tube and ply washer are not glued well and the tube move a bit but the gearbox still runs. When the motor runs the tube bends to the right a bit. I was thinking of adding a support on the back of the tube. Just a peice of ply with a half moon for the motor and a slit in top for the tube. Probably would only have to be 1/128" thick to keep the tube from moving to the right.
Ocasionally if I let off the throttle too quick or the plane hits the wall the pinion slips out and off of the spur. It didnt do this on my first flights. I guess I need to take the thing apart, remove the old glue and reglue.

Thanks for posting the links.

Peter
I'm glad that the gearboxes are inspirational.


Billy

Hahahaha... That is one of the greatest things I've ever seen, I couldn't help laughing from excitement! It floats around and maneuvers better than any plane I've seen, it looks like it climb rather well also. I wish it was mine. I am definately going to have to find the time to finish my project now. Absolutely amazing Billy! Excellent work!


Matt

Matt
Thanks
I laughed and laughed when I first flew the plane too.
Glad the excitement goes through the video.

I think I repaired the gearbox. Instead of removing it I used a 1 ought red sable brush and painted some acetone around the cf tube / ply joint then adjusted. A drop of acetone is too much so brushing it on keeps everything else from comming loose. Repairs now become fun. Painting is another hobby I like to paint small pictures.
The plane seems to fly a bit faster and fly level at less throttle with the repair.

Billy

Billy,

I really like your watch gears. Tell me, most of the ones I see have a very small shaft already in them. How do you remove them, do they punch out easily? After that, then just ream the hole out, right? Thanks.

Rance

Rance

Yes the shafts punch out easily, then they can be reamed to match up to the shaft.
You can see on the most recent one I used a pinion to match up the spur to the cf shaft.
Almost a perfect fit and works better than wire insulation which can make the spur off center very easily. One of the challeges is finding small tubes that help to mztch everything up.

Billy

Anybody have some gears they would be willing to swap for some Lipo cells? I have a lot of 600mah lipo cells intended for use in Siemens phones. They are brand new and good for 4-5C. I have tried to get a hold of gears via Ebay here in Germany but there is little on offer and when there is a lot they get sold for quite a lot of money. Something that will fit a 4mm pager setup - 5:1 - 8:1

TIA

Michael

Instead of a full second upright, Billy, why dont you try a support stick, a thin one between the washer and the motor can, unattached, and wrap a bit of thread to hold it down? I believe this will help support, the stick will keep it a certain distance from the can and the thread makes it a tripod. Possible?

Pete
That would work.
The gearbox no longer needs a back support i found it had come unglued so I painted some acetone on it and repositioned and it has been working great. I had to readjust the thrust line afterwards because the loose thrust bearing was pulling to the right.
I think a stick would work fine if you wanted the extra support Might be good for lower ohm 4mm motors to use a stick..
Billy

Oh :-P I didn't see that you had it working perfectly yet. Excellent job, by the way :-D Are there smaller gears you can get your hands on? I know all you need for a lighter plane is a smaller motor :-P

Some of the watch gears are pretty small. There are smaller gears than the ones I used in the photos. Look at Ben's photo. Those are pretty small.

Billy

Hey Guys, I have a question about a gear "term" that i dont understand. alot of companies say that they sell mod 0.2 of Mod 0.3 gears. I feel like a total idiot by asking this question, but What is the Mod, and how do i measure it?



thanks, Jon

Jon,

the "module" of a gear is the ratio between the count of teeth and the working diameter in mm of the gear. It can be used to calculate the needed shaft distance. For instance, if you have one gear with 10 teeth and one with 50 teeth, both with mod=0.2, then the shaft distance has to be (10+50)/2*0.2 = 6mm. The needed "play" between the gears is (or should be) calculated into the shape of the teeth, so you generally can use the theoretical distance calculated like above, if you are able to manufacture it as exactly as needed.

Hope that helps.

Regards, Jochen

so for instance, If a gear has 60 teeth, and a 10mm diameter, then the ratio would be 60/10. this would come out to 6 mod, am i correct?

Also, your equation simplified is 60/0.4 =6. how does this come out to 6? 60 divided by .4 = 150, am i correct?

Originally Posted by jonathan8388

so for instance, If a gear has 60 teeth, and a 10mm diameter, then the ratio would be 60/10. this would come out to 6 mod, am i correct?

Also, your equation simplified is 60/0.4 =6. how does this come out to 6? 60 divided by .4 = 150, am i correct?

Plenty of information here: http://www.roymech.co.uk/Useful_Tables/Drive/Gears.html

m = d / n
m = 10 / 60 = mod 0.167

That site helped alot, thanks. Also, Is there any way to find out the number of teeth on a watch gear, when I dont know the Mod of the gear? It seems that to find the Mod, i need to know the # of teeth, and to find the # of teeth, I need to know the mod. I hope i dont have to count the teeth by eye