He is at it again! 1:50 Dozer Conversion

[Rvjimd]

Scott,

Ya, I remember you telling me that about the cog wheels, I'm probably going to try that at some point.

Rcp, the machine is made by SpecCast. Is is labeled as 1/16 scale, Oliver OC-12 crawler with blade. They make a version without the blade for about $5 less. That one comes with an umbrella.

Here is a picture of the SECOND one I just bought today along with a few build pictures I took.

http://youtu.be/zWuuw7ka4qE

Jim

[Rvjimd]

Scott,

Do you have a pic of the knife edge on the cog wheels? When I read the last post, I made me pause. I would have shaved off the points? Now I'm confused...

Jim

[Rvjimd]

Got the blade control working. I'm happy with the overall function of blade and tracks. I need to see if I can find some metal crown gears to use in place of the plastic slot.it crowns, they are not going to take the abuse.

And I need an operator! Are there 1:16 scale figures that would work for me as an operator? Would I find something like that at walmart or a toy store?

http://youtu.be/JG2plmeSXEo

Jim

[SmallHaul]

It runs great Jim, good job.

Bruder people are 1/16 and look ok.

i tried to take pictures of the drive sprocket teeth last night and it just doesn't show how i modified them.

Give me a call today and i'll try to explain it better on the phone.

[kaptain Jack]

This is great, is the blade hydraulic?

[Rvjimd]

Jack,

No, everything is micro servo. The blade lift servo just pokes out the right side where a standard one leg servo horn is attached to the blade frame with a short piece of wire. I'll get some more detail pics eventually, once I get it all refined and work out some bugs.

I'm putting on two new pinnion gears this morning, the first ones I made too thin and they would not stay aligned good enough. Got a second pair and made them a bit taller.

Jim

[TRUCKMAKER]

Jim, I was searching for stuff on the forum and found this thread, didn't know if you've seen it, check out the first post!
http://www.rctruckandconstruction.co...e+truck+forums.

[Rvjimd]

Ya, I had seen the video once before. The more I work with the ginger stuff, the more I like it. And the 1/16 STILL seems small even after working on some 1:50 stuff!

Here is the latest video of my 1:16 dozer. I have switched over to gear motors for the drives. I'm installing a wedge now to hold the motor and pinion up against the crown gears. I am still searching for replacement crown gears. I'm using the blue slot.it crowns now I think they are 24 or 26 tooth,but the plastic is not going to hold up.

http://youtu.be/1VZZfcgRaB4

Jim

[TRUCKMAKER]

Looks like it works great, seems to be smooth but sounds like gears jumping towards the end, or is that just normal track noise? Anyway nice job!

[Rvjimd]

Truck maker,

That was probably the pinion slipping on the plastic crown gear. I'm in the middle of yet another version. I'm making the rear end of the chassis out of aluminum angle stock so I can position the two drive motors where I want them and I'm using two steel pinions instead of one steel and one plastic crown.

Film at eleven!

Jim

[modelman]

Really nice work on the conversion jim- you said you are making more changes so this should be a fine model when completed. Any updates on the wooden crane with the clamshell?

[Rvjimd]

Tom,

Thanks for the comments. I hadn't heard from you in a while, wondered how you were getting along. We are coming to Florence in a few days to check on the boat.

I haven't done anything to the wood crane since we got back from PA. I still need to paint it and I want to rebuild the cab. I slapped on a balsa cab but it needs to look better than it turned out.

I ordered some stronger versions of the gear motors that should make the dozer work really good. I have a few more details to take care of but I basically have the aluminum rear end finished and tested it yesterday. Works good but the low power motors I have on it no are just a bit to weak and they stall just about when it should start to slide a track.

I also ordered some new speed controls that I hope are smaller than the HK xcar 45 ones that I'm now using. They are just big enough that it is hard to cram it all under the hood.

Here is a pic of the chassis mod.



Jim

[john]

hi im new to this, been a gm mechanic for a few years now, not sure what kind of voltage your looking for but some of our remotes use a 12volt battery smaller then a AAA they last for an average of two years running a lcd display, if it helps for your size restrictions, also it you need lower voltage for your reciever you can drop the voltage with a diode or several each diode will give you roughly .5 volt reduction

[Rvjimd]

Hi John, welcome to the forum! I'm honored that you pick my thread for your first post!

The way it usually turns out, like on my dozer, you need at least one speed controller, which provides the voltage to a typical DC motor. The speed controllers also provide 5 volts for the radio reciever which will I turn power any servo motors plugged into the reciever.

Trouble I'm having is that with the newer style brushless motors, the older style brushed motor controllers are harder to find in the smaller sizes. I DID manage to find some in china, so if they turn out like I hope they will solve my space issue.

As for battery power, the latest and greatest is LiPo, which has great power density. They can be a bit sensitive to charging/discharging and can be damaged if not treated right. One of the functions available on most speed controllers is low battery voltage cutoff, so the controller shuts down the output to the drive motor before the voltage dros below a threshold that would damage the battery.

Jim

[modelman]

Mods look good jim, but I can see you need larger gearmotors for a dozer this size. I'm sure you will get it right.

[john]

thanks for the info, i always wondered about the esc. your project looks great by the way, im used to building hot rods an thought id try something different im used to running d7 cats and 320 trackhoes from farm experience. started my first rc conversion on a jd 4x4 with duals but i used a damaged ford 150 rc truck for the controller and reciever only 2 channel but it did the job, but the next project is a cat hoping to either find d7 17a or simular. i have alot of mill experience. would you if you were to build another 1/50 scale use two motors or make a diff and have brake steering. i going to build a few bigger ones adn learn more about the electronics before tackling a small model, thanks again for showing your talent.

[Rvjimd]

John,

Your diff and brake question is a good one! I don't know for sure, but the guys scratch building the bigger tracked machines are all using two motors I think? I would guess that getting the brakes to work as smoothly and easily as using two motors would be harder than the simple two motor setup.

As you prowl around here on the site you will figure out the handful of guys with the bigger scratch machines and they should have a good answer.

Jim

[Rvjimd]

Tom,

I ordered three more sets of motors. They make three different versions of the motor in that size. I think there is going to be at least one that should work. What I have now is almost strong enough. On the bench, they feel real strong, but they need just a bit more grunt.

I think one set is a bit higher rpm and higher stall torque, so I'm hoping I can re gear for the rpm and get about what I need for speed and torque.

Jim

[john]

ya your right, i had the idea of one soleniod sliding a pin either left or right to lock into the drive sprocket to positive lock, but it would not be as smooth as the two motors, thanks again, i dont know many people on here if i need a hand with the esc can i ask apon you?

[SmallHaul]

Jim,
You could always use the control board out of a cheap but powerful servo to use as a speed controller with smooth forward to reverse action.

You would have to add resisters to the servo board to give you "center" just like converting one for continuous rotation.

i am sure the control board in this servo could feed up to 2 amps to a motor and i doubt you would even draw 2 amps.

http://www.hobbyking.com/hobbyking/s...Fc07OgodjU8Alg