Saladin scratch build

Heng Long/WPL are now manufacturing 1/16 scale RC trucks, so it seemed sensible to create a forum area dedicated to the amazing things that members are doing with them. Post your builds, mods, and tips here.

Postby AlwynTurner » Tue Jan 15, 2019 10:06 am

I seem to have a few spare truck bits lying around and I've been trying to think of something to use them on. Then last night I was having a sleepless night and came up with a few ideas for building a Saladin armoured car

Image
Image

I have a cunning plan to make the first 4 wheels correctly steerable (large turn on the front pair, smaller turn on the second pair. I am hoping to find a way to drive all six wheels but that could be an interesting design problem. Anyway the first priority is the Diamond T rebuild and then in any spare time I'll have a bash at the Saladin. If it works out I might even do a kit.

Alwyn :thumbup: :wave:
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Postby AlwynTurner » Tue Jan 15, 2019 10:43 am

Here's the cunning plan for the steering
Image
It's basically accomplished by having the two steerable axles facing one another with a pivot bar between them. It will just take a bit of experimentation to determine the pivot point.

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Postby midlife306 » Tue Jan 15, 2019 1:08 pm

Ingenious young man


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Postby Lo_Thar » Tue Jan 15, 2019 1:56 pm

Yeach good idea - i use it in my project

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Postby mcevoyi » Tue Jan 15, 2019 2:00 pm

Here you go Alwyn
This is howni Did it...
Seems to work better when the link arms are diagonal to each other
It seems to balance out the force from the servo
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20190115_125742.jpg

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Postby AlwynTurner » Tue Jan 15, 2019 2:04 pm

That really helps, thanks, and thanks everyone for the good words

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Postby wibblywobbly » Wed Jan 16, 2019 8:16 am

I hope you can figure this one out. I attempted four wheel steering and eight wheel drive on a MAZ537, and failed miserably. :|
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Postby AlwynTurner » Wed Jan 16, 2019 9:53 am

Hi Rob, I think I have a few things going this time as the new parts for the wpl allow for very short prop shafts
https://www.ebay.co.uk/itm/For-1-16-Mil ... 2749.l2649
and there is a transfer box that should just about squeeze in if I use a shoehorn.
https://www.ebay.co.uk/itm/Metal-Transf ... 2749.l2649


Alwyn :thumbup: :wave:
Last edited by AlwynTurner on Wed Jan 16, 2019 10:05 am, edited 1 time in total.
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Postby wibblywobbly » Wed Jan 16, 2019 10:02 am

It's tight, no two ways about it. Driveshafts and steering arms were the biggest issue for me, not helped by me installing a two speed gearbox. I also discovered that the cheap Hobbyking servo splitters are very hit and miss with actually working, and that it really needs an SBEC to power them all. Mounting/rewiring servo's to run in reverse were another little challenge. I had horrible interference and glitching. Seeing as I was faced with spending a small fortune on a £20 truck...I took the cowards way out and stuck it all on a dusty shelf. :D

If the Saladin works, it opens the doors to a Stalwart..., so watching this with interest. :D
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Postby AlwynTurner » Wed Jan 16, 2019 10:10 am

The trick with the steering will be to thread the steering links around the propshaft using these
https://www.ebay.co.uk/itm/RC-Car-Truck ... 2749.l2649
and threaded rod, and use mcevoyi technique to get the wheels to cooperate. I'll have to use a modified version as on the saladin the turn on the second pair of wheels is less than the lead pair.

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Postby rochesb » Wed Jan 16, 2019 11:06 am

A Saracen would be another one to add to the list :)
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Postby Son of a gun-ner » Wed Jan 16, 2019 11:11 am

Wow, I've always loved these armoured cars :thumbup:

I'll definitely enjoy watching this build Alwyn :thumbup:

And Mr mcevoyi is dead right, the forces are directly opposite and therefore balanced as best they can be, far less strain on the servo :thumbup:
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Postby AlwynTurner » Wed Jan 16, 2019 11:33 am

Thanks guys, yes once I've mastered the chassis, many things become possible. Here's the stalwart illustrating the differential steering between the first and second set of wheels
Image

Alwyn :thumbup: :wave:
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Postby Son of a gun-ner » Wed Jan 16, 2019 11:48 am

Will this help Alwyn.

Image

As you only have three axles, obviously the 90 degree base line would come from the centre of your fixed rear wheel :thumbup:
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Postby AlwynTurner » Wed Jan 16, 2019 12:46 pm

Yes that helps a lot - Thanks

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Postby Son of a gun-ner » Wed Jan 16, 2019 12:50 pm

Cool and good :thumbup:

Obviously that's only an example I found to illustrate, the dimensions and angles will be different, but the formula is the same.
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Postby AlwynTurner » Wed Jan 16, 2019 1:21 pm

Made some progress

Image

I'm definitely going to need metal parts on this. I redesigned the leaf spring because the main leaf on the thingiverse version wasn't strong enough for what I need. I've also redesigned the spring hangers - more on that later.

Alwyn :thumbup: :wave:
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Postby Will01Capri » Wed Jan 16, 2019 4:13 pm

Son of a gun-ner wrote:Will this help Alwyn.

Image

As you only have three axles, obviously the 90 degree base line would come from the centre of your fixed rear wheel :thumbup:

beat me to it

But for me i would use seperate servo on each axle. Use different length servo arms on each and 3d print a new hub with longer arm on it for one of the axles or maybe both and play with the steering linkage to pivot point.
I did this on my rat rod designs and also had to do it on my crawler.

As for full steering turn, you could also cheat and put servo limiter in place to avoid max movement on one of the axles.
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Postby AlwynTurner » Wed Jan 16, 2019 8:21 pm

I metioned the brackets for the suspension, here they are
Image
Image

Alwyn :thumbup: :wave:
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Postby AlwynTurner » Thu Jan 17, 2019 6:39 am

I suddenly realised the answer to the drive problem isn't a transfer box, its two motors as in Wills build. It completely avoids the tight space problem, plus the motors are very compact. Its also a much cheaper solution. Eureka! :D :crazy:

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