WIP: Tiger Tank mid production 1:15 scale R/C

[Captain Green Hair]

Hi,

For quite some time now I have been working on a 1:15 scale R/C Tiger tank. It is a mid production tank from 1943.

This one didn't have the air filter system on the back and also had some other less visible changes from his predecessor.

My model doesn't have Zimmerit, the camouflage simply makes this impossible.

I'll first show you some shots of what she looks like now:

And my first ever Miniland scale figure, the commander:

I think the model looks quite all right so far, however, it drives like a wet towel.

I've started about 10 months ago and tried just about everything to make it run properly. My hands are in my hair!

I've used the principle of Sariel's torsion suspension system. I've made it a little sturdier to properly carry the weight and to keep the tracks running smoothly around the disk wheels.

The 2 XL motors drive the large sprocket wheels directly, as you can see here:

And here is what the inside looks like right now:

So, please help!

Any tips that may lead to a smooth ride are more then welcome.

Thank you in advance!

[DLuders]

I like the camouflage color scheme on your Lego Tiger Tank! Sariel's torsion suspension system (pictured above) is a great way of allowing the tank's wheels to roll over obstacles.

When you say that your tank "drives like a wet towel" and you want suggestions on how to make the ride smoother, are you looking for PADS on the Technic Links? Mortymore had some ideas about adding rubber bands through the holes of the Technic Tread parts:

Note that the BLACK Lego Technic Treads (which you have used) do not form as tight a circle as the older, Light Bluish Grey treads. See this TechnicBRICKS article.

[Captain Green Hair]

I like the camouflage color scheme on your Lego Tiger Tank! Sariel's torsion suspension system (pictured above) is a great way of allowing the tank's wheels to roll over obstacles.

When you say that your tank "drives like a wet towel" and you want suggestions on how to make the ride smoother, are you looking for PADS on the Technic Links?

Note that the BLACK Lego Technic Treads (which you have used) do not form as tight a circle as the older, Light Bluish Grey treads. See this TechnicBRICKS article.

Thank you Dluders!

Yes the torsion suspension works great!

I'm not looking for pads, I don't think that is the problem.

It drives straight forward, but on turning and/or going over obstacles, it stalls.

That is the problem.. :/

Thanks for the heads up on the links, but I had to have the black ones for the realistic effect.

[allanp]

Sounds like you need more gearing down. Try swapping the 12t bevel and 20t bevel gears round so you have a 12:20 reduction, that might be enough.

Edited June 19, 2011 by allanp

[Brickend]

How is the track tension? Is there a lot of friction? May be worth replacing the rear idler with a sprocket just to ensure that the track returns to the drive sprocket as in line as possible, if friction is an issue.

[Captain Green Hair]

Thanks for the ideas guys!

Sounds like you need more gearing down. Try swapping the 12t bevel and 20t bevel gears round so you have a 12:20 reduction, that might be enough.

Good thinking, but unfortunately my current front doesn't allow the swap. I also don't want to make it too slow...

How is the track tension? Is there a lot of friction? May be worth replacing the rear idler with a sprocket just to ensure that the track returns to the drive sprocket as in line as possible, if friction is an issue.

That is an idea I'm considering, however, the real Tiger has only front sprockets.

I've now swapped the small 12T bevel with the wider one, this grips better I see.

I'm now beginning to worry that it is also a structural problem, it keeps ripping the front frame apart..

[DLuders]

I'm now beginning to worry that it is also a structural problem, it keeps ripping the front frame apart..

It seems that the "studded" construction of your tank cannot withstand the turning movements without coming apart. The many 1x1 bricks that you have in your outer (camouflaged) shell does not help much. From the photographs, it seems that there are no Technic Bricks or Technic Liftarms to "tie" your sides together.

One could use a frame of Technic Bricks, and fill the pin holes with 1/2 pins that can hold Plates on the outside surface. The inside could be braced with Technic Liftarms holding the Technic Bricks:

Edited June 20, 2011 by DLuders

[Superkalle]

Just wanted to say - Love what you're doing here Captain. Really looking forward to following this build!!

[Captain Green Hair]

Ok, so the first advise I have incorporated is switching some gears.

Now my gearbox looks like this:

This certainly improves the driving capability, but also makes it rather slow.

I'm afraid that when I continue building the model, it will become heavier and even more slow..

Does anybody have a good idea to make it slightly faster?

Just wanted to say - Love what you're doing here Captain. Really looking forward to following this build!!

Thanks Johan!

[Brickend]

Ok, so the first advise I have incorporated is switching some gears.

Now my gearbox looks like this:

This certainly improves the driving capability, but also makes it rather slow.

I'm afraid that when I continue building the model, it will become heavier and even more slow..

Does anybody have a good idea to make it slightly faster?

Thanks Johan!

Your gear system is overly complex for what it needs to do to create a 1:1 ratio between the motors and the sprockets - see this for a simple version of the same result:

vincez01 - http://www.brickshelf.com/cgi-bin/gallery.cgi?f=476366

As for speed, it sounds like you needed the torque from the lower gear ratio, compared to your previously higher ratio. I think your undercarriage might be generating a lot of friction as well, but I'm not sure as it is unconventional (but I like it in terms of realism).

You could add another battery pack (one for each motor) or you could add selectable gear ratios. Fast for flat, straight-line speed, slow for hills and turns - but both solutions require more space and add more weight. You may have to accept that you have reached the limits of the PF setup.

Edited June 26, 2011 by Brickend

[Captain Green Hair]

Your gear system is overly complex for what it needs to do to create a 1:1 ratio between the motors and the sprockets - see this for a simple version of the same result:

http://www.brickshelf.com/cgi-bin/gallery.cgi?f=476366

As for speed, it sounds like you needed the torque from the lower gear ratio, compared to your previously higher ratio. I think your undercarriage might be generating a lot of friction as well, but I'm not sure as it is unconventional (but I like it in terms of realism).

You could add another battery pack (one for each motor) or you could add selectable gear ratios. Fast for flat, straight-line speed, slow for hills and turns - but both solutions require more space and add more weight. You may have to accept that you have reached the limits of the PF setup.

Is that tank your work? I really like that one and would love a video of it running.

I also ordered 2 more large sprockets for the rear wheels, that might help as well.

Next time I'll share some pictures of the frame as well, I can't see it making a lot of friction. But then again, I'm a Technic noob.

[Brickend]

Is that tank your work? I really like that one and would love a video of it running.

I also ordered 2 more large sprockets for the rear wheels, that might help as well.

Next time I'll share some pictures of the frame as well, I can't see it making a lot of friction. But then again, I'm a Technic noob.

I'm afraid it is not mine, I have edited my post as I did not intend to in any way misrepresent vincez01's work.

[Montage]

If you would like a Tank with high speed and also to have the luxury of having a large torque output than you may want to look into a gearbox design. Maybe one with up to 3 speeds or even possibly just use a subtractor set up so it wont create as much friction when you turn and the tank itself will handle the weight better and drive nice and comfortable.

[Benny3000]

Here is the Vincez's tank video :

[JunkstyleGio]

Even though I'm not a fan of any "instruments of war"; this model look quite impressive!

[Captain Green Hair]

So I've taken all your advice to heart and changed the gearbox so the conversion is now from a big to a small gear.

It made it slower, but it drove really nice.

So I started building up some more and the tank now looks like this:

The turret is a bit more WIP:

Now it starts to look like what I had envisioned, but again it drives like a wet cake on skates!

I'm afraid I've made it all to complex and feel like just giving up...

[DLuders]

No, don't give up! I like the look of your Lego Tiger Tank. What problems are you trying to overcome?

[Brickend]

I really like this Tiger, not surprised it is a bit of a wet cake with all that weight, but the real thing was a heavy monster.

[timslegos]

Awesome looking tank!!! Dont give up!!!!

tim

[Alasdair Ryan]

It looks great what are the problems you are facing?

Driving like a wet cake on skates sounds like it is the lack of control that is the problem but if you geared it down enough then this should not be the cause.