[TC29] Bullwinkle -Engine and steering update-

[MangaNOID]

Good old TC contest to make me build something.

This Will hopefully be a retro, self styled (not copying real one) bulldozer and some styling I have in mind reminded me of an old cartoon character that shares a name with this topic name.

Pneumatic functions and air tank will be fed by two small pumps driven by the tracks.

 

 

 

some over all proportions I’m working to below

-blade will have lift, tilt and turn

-hopefully a rear ripper thingy

-‘self filling’ air tank from pushing it around

-some steering that I’m working on for the tracks to work from the steering wheel

-fake engine, track ‘tensioners’ blah blah…

 

Edited July 2 by MangaNOID

[Aurorasaurus]

1 minute ago, MangaNOID said:

some steering that I’m working on for the tracks to work from the steering wheel

I'm really curious what you come up with because I've been tinkering with the same problem. I tried using a diff between the tracks (with one tracks axle direction inverted) feeding a clutch and then the steering wheel with a self centering mechanism. But I got bored before getting anything reliable. I hope you can make something work!

[mdemerchant]

Project looks good so far.  It's an ambitious number of functions to pack into the scale, especially with pneumatics.  One minor comment, I don't think bulldozers have steering wheels as a general rule.  I can't think of any tracked construction vehicle I've ever seen that does have one.  Maybe you could do two levers driven off the tracks with really weak clutches, that would look kind of realistic when the tracks are driven.

[Paul B Technic]

Very interesting idea to drive the pump off the tracks, I am keen to see what you come up with.

[MangaNOID]

On 6/8/2025 at 8:45 PM, Aurorasaurus said:

I'm really curious what you come up with because I've been tinkering with the same problem. I tried using a diff between the tracks (with one tracks axle direction inverted) feeding a clutch and then the steering wheel with a self centering mechanism. But I got bored before getting anything reliable. I hope you can make something work!

So if I understand your way correctly then I think the inverted rotation is a problem from the ‘pushing the vehicle’ aspect?

Here below is one of two ways I’m trying to ‘steer’ the tracks from just pushing the vehicle.

This is a mock up (to test the idea) of what would be a proper gearbox if I had enough of the 12T and 20T clutch gears (in the post on their way to me)

Both tracks are locked together by the gears, selectable by the wave selector between the clutches (there is one 12T and one 20T gear missing in this photo as the gears are not clutch gears  of course) this will force one side of tracks to be faster/slower than the other (changeable by the wave selector) which forces the vehicle to turn left or right.

The elastic bands are on there to test how it works on hard surfaces as I don’t have the little rubber gromets yet.

Surprisingly this works OK. Not as good as proper tyre steering of course but happy enough for the tracks.

 

 

The other steering method I will mock up and try on the weekend is a little different (brake steering) so cant wait to see how that goes plus it will use way less space than this gearbox which is a bit in the way.

 

On 6/9/2025 at 10:31 AM, mdemerchant said:

One minor comment, I don't think bulldozers have steering wheels as a general rule

Its true but this will not be a replica of any real machine so I have design choices. Also I am trying to get steering to work which will be better with a wheel to turn (?) when pushing. It will also have many pneumatic levers so two less levers for steering will be better :)  

[tseary]

That steering gear is really cool! I was wondering how to build a skid-steer vehicle with the Technic Control+ hub, which is intended for rack-and-pinion steering. This could be a way to make that work.

[MangaNOID]

So brake steering is fail 🙁

I had this setup as braking for each side…

 

 

Although the ‘brakes’ worked, there was two problems.

1- the tracks don’t supply enough grip on anything other than thick rug/carpet to stop one side turning whilst pushing

2- the small pumps in the tracks gave too much friction in the tracks to make the tracks turn freely enough to allow for the steering to work.

So I either give up steering or maybe motorise with the gear steering but not much room and don’t want to be too ambitious and end up with nothing.

worked on design layout a bit…

 

 

 

[MangaNOID]

I have fixed the steering problem!

I changed the bulldozer to 9V power which slotted in perfectly to the under chassis I already had due to the ‘vintage’ high lift design in mind.

 

Same brake steering method as before, but works so much better when the tracks are powered instead of pushed! Works great with the steering wheel instead of typical tank steering levers. Very playable 

 

Brake steering is located on the higher rotation axles before everything is slowed down and torqued up for the tracks.

 

Forward and backwards direction will be controlled via some lever thing from drivers seat area direct to battery box switch.

M motor crammed on top of fake 4 piston engine with vintage steampunk type of vibes pneumatic pumps hanging of either side. This will sit above the diff.

 

 

 

[1980SomethingSpaceGuy]

A lovely little machine!
Looking forward to see it finished.

[MangaNOID]

I had this steering column at first which with the half stud offset near the top was perfect to fit in the bulldozer but of course the tan 4L axels are not held in place so I spent a little while coming up with the grey version which is much better built. Just not as aesthetically pleasing 

Below was my fist engine attempt but it didn’t work well with power going through the fake engine to the pneumatic pumps at 1:1 

 

So I changed that to this gear setup and flipped the m motor upside down which now works well… although I haven’t tried pumping any pneumatic cylinders yet 

 

 

Squeezing everything in under my favourite olive green panels… it seems to be going well so far.

Cut away view…

 

Still lots of tweaking to do, finish the blade, test the pneumatics, maybe stretch the track length a bit or add a couple rollers as they are a little loose for my liking.