Starting a new build... something...

[ChILd_ReBoRn]

Um, guys.. I need help.
I got my servos today. 10kg/cm. They will be plenty strong, but I'm not sure how to fit them, so could use an idea...

I have several ideas, but not all fit in visually, although mechanically some sound better than the other.


[IMG][/IMG]

first option is to place a servo on the side of the chassis, and use a simple lever to lift one blade arm. Both arms would be firmly connected, so when one moves, other one follows. I could add a bogey arm on the other side just to keep the symmetry.

Second option would be to place 2 servos (one for each arm), and splice the wires from one onto the other (Since I don't have that bridge thingy for connecting multiple servos), But I would have to swap the polarity of one servo so both arms would move in opposite directions. That would give me symmetry, double the lift power (massive overkill), and I would mess up my servo cables.

third option is to place a single servo in the middle of the chassis and use a lever system from servo arm to the middle of blade arm connection. So it would pull on the middle, and lift both arms simultaneously


P.S.
How to slow down the servo? I have a feeling it will work way to fast. I saw some speed reducers for servos.. is that the best option?
What do you think?

[frizzen]

That's pretty wild looking.

I'd try to go #3. It won't try to torque it funny like #1, or trying to balance servos or program digital ones like #2. If you want to have blade roll as a feature, then option 2 on seperate channel with mix options.

Many radios have servo slowing as a built in feature, but it's often hidden deep in the menus as a gear or flap thing.

Servo slow
https://hobbyking.com/en_us/turnigy-...___store=en_us

[ChILd_ReBoRn]

Yeah.. it's wild looking.. I'm making it up as I go. No CNC or a lathe.. so all options are open, LOL...

Ok.. will concentrate on option 3

[ChILd_ReBoRn]

https://youtu.be/DQl8bhZe0uU

I must say that I am very pleased with the servo speed. I limited the range on my flysky, and everything works great. Plenty of torque in that little servo.

edit:

Although this works, I really don't like how it looks. I think I'll go with the 2 servo option. It will look much cleaner, and it will alleviate the need for a big slot on the front of the dozer for the arm to move...

[frizzen]

I was thinking more like blade servo tucked down low between the bogie wheels. Replace nut/bolts holding the blade arms with a T shaped cross-rod, with the center leg of 'T' as an arm close to servo horn length for linkage mount. Maybe square drive / keyway / weld on the ends that the blade supports. Removable bushing plates for the rod if the cross rod is permanent mounted to blade supports.

*i don't know how to build bulldozers*

[ChILd_ReBoRn]

The idea has merit, and I was considering it, although I was opting for a classic round rod to hold the blade arms, and a servo linkage brazed on. That would be clean, but it would put a lot of strain on that little servo.

[ChILd_ReBoRn]

I've gone with the 2 servo option. One servo got "hacked". Resoldered the motor and POT to invert the direction, and I like this much better. More power for the blade...

double servo blade lift

I've added another servo to the back for a 3 point hitch, But since I managed to get the blade rather clean, I really don't like the 3 point look . It's just.. messy. Still not sure will I leave it or not. If I stick to the original M105, I'll lose it and add a winch...

We are now at healthy 1500g without the battery..

[ChILd_ReBoRn]

[ChILd_ReBoRn]

motors mounted, and mixing tested

Still missing the hazard light, side lights and unfortunately.. Tracks. They are running late.
I've decided to loose the 3 point hitch. Possibly make a winch...

[ChILd_ReBoRn]

Made the blade today. Missing the support struts, and the blade is way to deep. Have to make it shallower. Burned my fingers, and mangled my diy spot welder..

[Wombii]

Nice compact layout. Looks like a solid shovel lifting mechanism. Good job on the servo reversing too. I didn't think of reversing the motor wires inside.

[ChILd_ReBoRn]

thank you. The tracks came in the post 2day.. finally. Will pick them up, and luckily, mount them 2morow

[ChILd_ReBoRn]

I've cut the blade, and shortened the blade arms. Made some blade supports, had to cut them in half, mounted only on per blade arm. When I fit the tracks, I'll see how much free space I have, so I'll either mount 2 per arm, or make some thinner ones.... I'm off work for 2 weeks, so I'll have to pause the build until then...

[ChILd_ReBoRn]

oh the agony.... the sprockets don't fit the tracks... goddamn. I've ordered some custom built... hope they fit...

[ChILd_ReBoRn]

So.. It's been a while. The sprockets were made by a friend. but alas, don't fit. I believe I can grind them to fit, but free time is really an issue last weeks.. so ... easy going...

[ChILd_ReBoRn]

Started on the shell. What can I say.. it's a learning curve. Still a lot of way, and a lot of putty to go....

[ChILd_ReBoRn]

slowly getting there...

[ChILd_ReBoRn]

It lives!

https://youtu.be/VJZ-yw8Kmtc

[ChILd_ReBoRn]

I think I have to lower the motors. That will be hard because the mount is fixed, and there's not much free space, but I have to try.. The drive sprocket is a bit too far...

[ChILd_ReBoRn]

https://www.facebook.com/RCiler/videos/566313257219508/