Smart suspension for tank or ripsaw

[oracid]

Here is a video where I show the implementation of a suspension that seems original to me.
I have already used this type of vertical suspension in some of my previous videos, but here I searched for a very minimalist solution that implemented very little means and offered great freedom of integration.
One of the difficulties was to bypass the 2L space at the track to achieve a gap of 3L at the connection of the suspension. This to facilitate adaptation to the assembly of Lego sets.

The small tank has no particular characteristic, it is there only to highlight the implementation of this type of suspension.

 

 

[Sariel]

With all due respect to your work, I think I see at least three problems:
- the upper ends of these, um, suspension columns? are going to hit the upper track if their movement isn't limited
- the columns don't seem very stable; the road wheels are sitting on long, thin columns that are only braced around their tops. I think I see plenty of room for wobble here and this would get problematic for heavier models.
- this solution needs the track to be very tall and the performance you're getting doesn't seem any better than with a simple torsion bars suspension (which is also way, way lower)

[Saberwing40k]

Yeah, I agree with Sariel. There is a reason torsion bar suspension is implemented in actual tanks. A real Ripsaw tank uses a kind of swingarm suspension. It's an interesting idea, for shock absorbers with rubber bands.

[shadow_elenter]

I like the out of the box thinking but mechanically I can't see any advantages for suspension.
I do see potential for this technique in other applications given the fact that you could potentially make very long travel in conjunction with THIS PART(axle flex might be an issue of course).
Thank you for sharing !

[agrof]

I also like this solution, and I understood that @oracid shows here an alternative track suspension - not a replica of actual solutions. Maybe the top of the suspension "foot" should have tiny rollers indeed, so as they sag to maximum, they guide the smooth roll of the track. This way also the necessary track tension can be set automatically, good idea.

I still love your video presentations and the way of gesture talking - it has a special and original charme. 

Edited April 28, 2018 by agrof

[oracid]

Thank you for your comments.
Yes, of course, I'm familiar with the limitations of this type of suspension and as you can imagine, I've been studying tank suspensions in Lego videos and books in my possession.

- concerning the limitation in height, it is an inconvenience easy to solve with a red piece below which would limit the movement. In addition, it does not seem very complicated to anticipate the problem in the design of his tank. But it is true that a large deflection is to be avoided.
- concerning the vertical stability, one could double the passage pieces of the axles so as to increase it and to prevent wobble.
- The "swing arm suspension" is a very good solution for ripsaw but unfortunately it takes up a lot of space and limits the number of wheels.
- definitely, I do not use the "torsion bar" which takes a lot of space inside the chassis with little advantage.
- I made a version with wheels in the upper part as tensor of the track. It works pretty well but beware of shifting the track in the opposite run of the sprocket.

My main concern is the number of wheels that must guide the track on its entire course.

Thanks again.

Edited April 28, 2018 by oracid

[Bartybum]

You could make the columns start halfway and have rollers on the top as well. That way the tracks will have rollers to hit instead of columns.

[oracid]

3 minutes ago, Bartybum said:

You could make the columns start halfway and have rollers on the top as well. That way the tracks will have rollers to hit instead of columns.

 I have made this, it works pretty well. Thank you for your suggestion.

[Sariel]

3 hours ago, oracid said:

- definitely, I do not use the "torsion bar" which takes a lot of space inside the chassis with little advantage.

Well, have you at least tried it? It takes just 1 stud height of chassis space, you can easily fit it into your tank's "floor", and the performance you get from torsion bars is excellent. See starting from 1:06:

 

[oracid]

Here, a variant with a stop of the actuator stroke and top wheels.

 

 

15 minutes ago, Sariel said:

Well, have you at least tried it? 

Like many here, you are a great source of inspiration for me and I will probably reconsider my position on this point.

[Bartybum]

I think you should try design the column with some forward-backward stability so it doesn’t bend

[Tommy Styrvoky]

Torsion bar offers a lot of advantages, such as variable stiffness, and relatively compact arrangement in a hull though you may want to look into Horstmann suspension if you are looking for a compact externally mounted suspension. a vertical travel setup like yours makes it difficult to mount anything above the tracks due to the large travel distance. a long travel bell-crank suspension like on some of the later war Japanese vehicles offers a lot of travel. 

The MS-1 or T-18 utilizes a similar setup to your design, however it has bogies, another issue with the design you have is when the vehicle comes into contact with a step it will exert a lot of force horizontally on the suspension arm, that is why with the t-18 you see the first road wheel features another dampener angled to improve the way the force is transmitted in both the horizontal and vertical fashion.

Edited April 30, 2018 by Tommy Styrvoky

[oracid]

Thanks for all the details.
I will consider all this more closely.