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The only clue I can see is that the device is mounted on an Australian Army International 2.5 ton 4x4 truck

 

That's a relief Richard I was dreading someone asking me about it. Yes it is in Australia.

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Dangerously close to the day job again.

 

It's fitted to an ACCO under test, and the only function of that sort of flimsy contraption is to measure distance, but apparently it isn't to measure distance, so ...

 

On a test vehicle, under load, it measures distance compared with the distance travelled by the front wheel over the same time, to give a reading of wheel slip under load.

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Dangerously close to the day job again.

 

It's fitted to an ACCO under test, and the only function of that sort of flimsy contraption is to measure distance, but apparently it isn't to measure distance, so ...

 

On a test vehicle, under load, it measures distance compared with the distance travelled by the front wheel over the same time, to give a reading of wheel slip under load.

 

Gordon what is an ACCO?

 

Yes one of the functions of the contrivance is to measure distance, others said it was a speedo but its not a speedo.

 

I think you are nearly there Gordon can you just clarify your answer please.

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Gordon what is an ACCO?

 

Yes one of the functions of the contrivance is to measure distance, others said it was a speedo but its not a speedo.

 

I think you are nearly there Gordon can you just clarify your answer please.

 

Now you are asking Clive ....

 

ACCO = Australian Constructed Cab Over, basically the Australian locally-built replacement for the Canadian CMPs that formed the backbone of the Australian Army during WW2.

 

http://www.mapleleafup.net/forums/archive/index.php/t-514.html

 

Basically distance travelled by thingy, MINUS distance travelled by front wheel, OVER, distance travelled by thingy, Divided by a hundred, EQUALS percentage wheelslip of the driven wheel.

Edited by Gordon_M
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In the times of uncertainty about whether electronic devices could withstand power nuclear surges, this device enabled navigation by the ancient Aboriginal method of using ley-lines...

 

So you are there Bernard I thought it was unlike you to miss a MO. I assumed you must have been outdoors sipping tonic water under a sunshade.

 

I'd like to say yes but I'm afraid its not quite the answer I was hoping for :D

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Now you are asking Clive ....

 

ACCO = Australian Constructed Cab Over, basically the Australian locally-built replacement for the Canadian CMPs that formed the backbone of the Australian Army during WW2.

 

http://www.mapleleafup.net/forums/archive/index.php/t-514.html

 

Basically distance travelled by thingy, MINUS distance travelled by front wheel, OVER, distance travelled by thingy, Divided by a hundred, EQUALS percentage wheelslip of the driven wheel.

 

Ah Gordon I'm much relieved it wasn't a simple answer as I thought might have missed a basic thing I should have known. Yes that's a very comprehensive link.

 

You're close but its not quite a distance thing in itself. Perhaps the full view will help.

 

App3559c_zps40926e5c.jpg

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I await the accurate answer with interest :angel: though from that photo it looks like it is still doing the same job, just measuring wheel slip under braking rather than driving - still a wheel slip indicator, with the thing under the number plate being a load cell.

 

Worth pointing out that if you winch the truck forward with the wheels locked and the thingy turning - it is still measuring wheel slip on the given surface, it's just 100%

Edited by Gordon_M
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Is it measuring brake distance - activated by the hose to the tow hitch when the hitch comes under additional pressure?

 

I know what you are getting at Lauren but its not quite that.

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I await the accurate answer with interest :angel: though from that photo it looks like it is still doing the same job, just measuring wheel slip under braking rather than driving - still a wheel slip indicator, with the thing under the number plate being a load cell.

 

Worth pointing out that if you winch the truck forward with the wheels locked and the thingy turning - it is still measuring wheel slip on the given surface, it's just 100%

Yes well done Gordon the thing under the number plate is indeed an Amsler Load Cell

 

App3559d_zps3c5eb0f4.jpg

 

Ok that is the apparatus. What might be on the other end?

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Yes well done Gordon the thing under the number plate is indeed an Amsler Load Cell

Ok that is the apparatus. What might be on the other end?

 

Just a big winch, really. You wouldn't need anything special, like a vehicle with a dynamometer or whatever, in fact the last thing you'd have at the other end would be a moving vehicle - possibly a winch truck with ground anchors.

 

Going further;

 

the test weights on the back of it just simulate the body weight. You would probably do this numerous times on numerous surfaces, and repeat with larger weights to simulate a full load.

 

On a dry surface you might get wheel slip due to less than 100% braking efficiency and that would take us back towards my original guess. On mud and earth, given army truck brakes, I'd expect the wheels to be pretty much locked.

 

Other test equipment you might find on it would be stuff like a pressure indicator / recorder on the hydraulic or air braking system, which would tell you the braking force that had to be applied to achieve 100% lock.

 

Amsler is now Roell-Amsler IMPACT.jpg and they still make test equipment such as this impact test machine - image from my day job about ten weeks back. As I said, dangerously close to my day job.

 

Go on, tell me I'm wrong and there is some huge technical thing at the pulling end too ?

Edited by Gordon_M
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Just a big winch, really. You wouldn't need anything special, like a vehicle with a dynamometer or whatever, in fact the last thing you'd have at the other end would be a moving vehicle - possibly a winch truck with ground anchors.

 

Going further;

 

the test weights on the back of it just simulate the body weight. You would probably do this numerous times on numerous surfaces, and repeat with larger weights to simulate a full load.

 

On a dry surface you might get wheel slip due to less than 100% braking efficiency and that would take us back towards my original guess. On mud and earth, given army truck brakes, I'd expect the wheels to be pretty much locked.

 

Other test equipment you might find on it would be stuff like a pressure indicator / recorder on the hydraulic or air braking system, which would tell you the braking force that had to be applied to achieve 100% lock.

 

Amsler is now Roell-Amsler and they still make test equipment such as this impact test machine - image from my day job about ten weeks back. As I said, dangerously close to my day job.

 

Go on, tell me I'm wrong and there is some huge technical thing at the pulling end too ?

 

Um well Gordon a Saracen actually. Two of them but taking it in turns. :D

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Um well Gordon a Saracen actually. Two of them but taking it in turns. :D

 

Cor, that's terrible :blush:

 

The whole test method should be built round applying the load in a measurable, constant fashion - having an Aussie driving a Saracen would give only very approximate results, you'd be far better off with a Diamond T and using the winch.

 

They probably had to use two, as if they were trying to load it evenly it would heat up the convertor in the poor Alvis quite notably, followed by that burning brake band smell, so swap to the other unit to let the poor thing cool down.

 

Can you tell if the Saracens had improved cooling - conventional or reverse flow - clouds of steam from the engine compartment or smoke from the transmission? :undecided:

Edited by Gordon_M
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Cor, that's terrible :blush:

 

The whole test method should be built round applying the load in a measurable, constant fashion - having an Aussie driving a Saracen would give only very approximate results, you'd be far better off with a Diamond T and using the winch.

 

They probably had to use two, as if they were trying to load it evenly it would heat up the convertor in the poor Alvis quite notably, followed by that burning brake band smell, so swap to the other unit to let the poor thing cool down.

 

Can you tell if the Saracens had improved cooling - conventional or reverse flow - clouds of steam from the engine compartment or smoke from the transmission? :undecided:

 

Gordon the trials aren't quite what they seem, it was to test the Saracens ;)

 

App3600_zps2cf7f61f.jpg

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