Another steam crawler

[Roger B]

I came across this while looking for some Hornsby oil engine videos. A challenger for Chris and Gail 

<a href="https://www.youtube.com/watch?v=fAAx_szUMxc" target="_blank">http://www.youtube.com/watch?v=fAAx_szUMxc</a>

#Invalid YouTube Link#

[b.lindsey]

Quite an impressive Crawler!!  Thanks for posting that Roger.

Bill

[Ye-Ole Steam Dude]

That is a great looking engine and a really nice sound.

Thomas

[Steamer5]

Hi Rodger,
 Now that is just so cool! Nice to see something different. Wonder if the gent did a build log anywhere

Cheers Kerrin

[crueby]

Thats tremendous! Thanks for the link!

[Roger B]

Looking through Christoph Beyers site he appears to be in NW Germany. In the comments he links to the following:

http://theoldmotor.com/?attachment_id=73385

http://www.ebay.co.uk/itm/182390881508

The Ebay link can be followed through to this article:

http://modelengineeringwebsite.com/Hornsby.html

[fumopuc]

... if you like more.
<a href="https://www.youtube.com/watch?v=keGtPdpjsio" target="_blank">http://www.youtube.com/watch?v=keGtPdpjsio</a>

[b.lindsey]

OK, a naive question here.  How does the steering work on this crawler??  Is it slowing one track down relative to the other or are both tracks being turned on some sort of gimbal arrangement?

Bill

[crueby]

OK, a naive question here.  How does the steering work on this crawler??  Is it slowing one track down relative to the other or are both tracks being turned on some sort of gimbal arrangement?

Bill

In the first video it looks like he has a clutch/brake on the tracks, to stop one while continuing to drive the other.

[fumopuc]

I think Chris is right. I will ask Christoph, he is a member of our German forum, he is not the builder but he knows the guy who made this beautiful model very well.

[b.lindsey]

Chris you could be right, but if so then he is doing that with the steering wheel??

Bill

[crueby]

Chris you could be right, but if so then he is doing that with the steering wheel??

Bill

Gotta be some sort of clutch/brake system or maybe a cone-drive there that offsets the speed of the tracks - looked in some of the other videos on it and could not see how it was done. Hope Fumopuc can get us some details, it is a magnificent piece of work!

EDIT:
While reading the article here:
http://theoldmotor.com/?attachment_id=73384
it says that on the original there were two brake bands, one on each side, that slowed on track at a time. These bands were actuated by the steering wheel. That would gibe with how the model behaves too - you can hear the engine load up and slow in the turns, and you can also see one track slow way down in a tight turn. There must be a slip clutch of some sort too, to let the engine keep trying to turn the shafts without stalling.

[Roger B]

This can be done with a normal differential gear between the two tracks. You can brake one track without stalling the engine but it applies an effective 2-1 step up ratio so that the load on the engine increases.

I did this on my steam Mechano version long ago. You can see the gear set in this not very good picture. The two arms along the side applied band brakes to the end of the differential shafts.

[crueby]

This can be done with a normal differential gear between the two tracks. You can brake one track without stalling the engine but it applies an effective 2-1 step up ratio so that the load on the engine increases.

I did this on my steam Mechano version long ago. You can see the gear set in this not very good picture. The two arms along the side applied band brakes to the end of the differential shafts.

Oh - right!   

[fumopuc]

I have got an answer from Christoph.
The model is working like the real one.
Each chain has a clutch. The steering wheel is used to solve one clutch and than the other chain has to push the tractor against the friction of the other chain over the ground. So there is realy power needed to change the direction.

[b.lindsey]

Thanks for the addition info!! Maybe it wasn't such a naive question afterall.

Bill