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Curious About Yaw Mech

Cyberdactyl

Misfit Multirotor Monkey
#1
I have a question for anyone who follows yaw mechanisms. I've searched over at Rcgroups but haven't found my answer.

My yaw mech is nothing special, it's a version of the David W's Rcexplorer yaw mech. But since there are so many pieces in the bag from HK of the 'front wheel mounts', I also used one for underneath the boom as a clamp. I made some shims with fitted grooves and coated them with epoxy from 3/16" Luan ply to fill in the gap on each side.

I also made a small luan inverted bed for the ESC which is hung from a skewer pin in the bottom 'wheel mount'.

Getting back to the main question. Has anyone seen a third wheel mount serving as a "clamp"?

 

colorex

Rotor Riot!
Mentor
#2
I would say you just invented that. I don't think it would be necessary on most types of boom as it's just extra weight.
 

Cyberdactyl

Misfit Multirotor Monkey
#4
The jumble of wires scares me though... ;)
The under-hanging ESC is indeed a small concern. That's why I have the landing leg angled over and under it. But a crash on the end of that boom will be a mess. I just won't crash that way. . . :rolleyes: :p

I tried to keep the "jumble" to a minimum. I also wanted to keep the weight to a minimum. My other goal was to have easy access to the XT60 after fighting with the connection access with my quad.

I used 25mm clear heat shrink on all the ESCs, and used it to directly mount the front ESCs to the boom with a thin layer of rubber between the boom and ESC. That technique for mounting ESCs works great. I turned the ESC vertical to minimize the the planform obstruction to the thrust column, yet utilize the flow for the ESC's heat sink.

I ran the wires inside the booms as in David W's 2.6 Deluxe.







One IMPORTANT tip David failed to mention in his tutorial is the ABSOLUTE NEED to round and smooth the ends of the inside of the boom openings. The carbon square tubes come VERY sharp with perfect 90 degree edges. If this is not done, the wire insulation WILL chafe or wear over time, and the wire will get exposed. MOST especially if you continuously fold the arms back and forth for transport. David's designs are fairly well thought through, and I was somewhat surprised he missed this critical aspect in his tutorial.

 
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Cyberdactyl

Misfit Multirotor Monkey
#6
how do you like the expensive carbon fiber blades? (have yet to try them)
They don't flex anywhere near as much as the plastic GWS, Slow-Fly, etc. props, so the vibration is greatly reduced. Also, since they don't flex, input response is crisper. They can handle very high rpm, where plastic will flatten or pancake. And in theory, they should be more efficient since they don't lose energy in flexing.

There two distinct drawbacks. One, of course, is the price. Don't use CF props if you're just learning. It's a waste of money, and you won't know the difference anyway. The other is they are NOT TOY PROPS. Meaning, they have ZERO forgiveness if you get a finger or forearm in a spinning blade. Plastic props will will give you a painful light slash, as they will flex before cutting too deep. Carbon fiber props will cut deep like a scalpel.
 
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crlock

Senior Member
#7
This is the yaw mechanism i designed for my tricopter, it's pretty simple, and helps to save your servo if you crash or hit something :) ( trust me, I know )
this mechanism is mounted on my "proof of concept" tricopter, later on this week i hope i can post the finished frame
8733506494_de6409f69c_b.jpg
 

Cyberdactyl

Misfit Multirotor Monkey
#8
Excellent.

That is one protected servo. What is that connecting the servo to the rocker arm? It looks almost like instamorph.
 

Craftydan

Hostage Taker of Quads
Moderator
Mentor
#10
crlock,

Have you run any bench tests with the motor running?

Instamorph is a great material, but I'd worry it would deform as the motor heats it up.
 

crlock

Senior Member
#11
crlock,

Have you run any bench tests with the motor running?

Instamorph is a great material, but I'd worry it would deform as the motor heats it up.
nope, i have not, but IM starts deforming at 60ºC (140ºF) and my motors barely get warm, so far i haven't had any trouble. I'm in the process of upgrading my frame, and one of the changes is the yaw mechanism, i'm changing the material of the motor mount for something a little more light. the major drawback of IM is the weight (if you are using a lot like me :p )
 

Cyberdactyl

Misfit Multirotor Monkey
#12
Mmmm, not sure I trust it up that high, but under ~115F (46C), I trust it for strength and fatigue close to, or as much as nylon.

I've used it for many things in the last 9 months since Chad Kapper made a video about it.