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Penman
Joined: 23 Nov 2007
Posts: 4765
Location: Swindon, Wilts.
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Bitumen Boy
Joined: 26 Jan 2012
Posts: 1736
Location: Above the snow line in old Monmouthshire
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 Posted: Sun Apr 09, 2023 9:26 pm Post subject: |
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| It's a new one to me, I wonder what the tracks are for? |
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Ray White
Joined: 02 Dec 2014
Posts: 6337
Location: Derby
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| Posted: Sun Apr 09, 2023 10:02 pm Post subject: |
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| ...and a strange RSJ poking out of the wagon over the turret top.? |
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BigJohn
Joined: 01 Jan 2011
Posts: 954
Location: Wem, Shropshire
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| Posted: Mon Apr 10, 2023 8:40 am Post subject: |
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| Ray White wrote: | | ...and a strange RSJ poking out of the wagon over the turret top.? |
I always thought this moved to provide a lifting point for using block and tackle.
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1974 Mk1 Escort. |
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ukdave2002
Joined: 23 Nov 2007
Posts: 4114
Location: South Cheshire
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| Posted: Mon Apr 10, 2023 9:13 am Post subject: |
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The dolly must be powered via some sort of PTO, otherwise there would be no point in having tracks?
Possibly for recovery over rough/ soft terrain and or where the recovered vehicle had damage? |
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Bitumen Boy
Joined: 26 Jan 2012
Posts: 1736
Location: Above the snow line in old Monmouthshire
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| Posted: Mon Apr 10, 2023 9:47 am Post subject: |
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| ukdave2002 wrote: | The dolly must be powered via some sort of PTO, otherwise there would be no point in having tracks?
Possibly for recovery over rough/ soft terrain and or where the recovered vehicle had damage? |
I think the dolly being powered by PTO is a good shout. But if the ground is soft, how is the recovered vehicle to be lifted sufficiently to get the dolly underneath the axle, and how does the tow vehicle not also get stuck? There are more questions than answers with this one! |
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Ray White
Joined: 02 Dec 2014
Posts: 6337
Location: Derby
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| Posted: Mon Apr 10, 2023 10:29 am Post subject: |
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| I agree there is a PTO but the tractor unit would have to be very carefully geared to the 6WD wouldn't it? |
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Penman
Joined: 23 Nov 2007
Posts: 4765
Location: Swindon, Wilts.
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| Posted: Mon Apr 10, 2023 11:15 am Post subject: |
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Could the dolly be just a load spreader?
After all the sort of small wheels you normally see on an ambulance are only about the size of the track wheels on this and a larger ambulance wheel would require A) A higher lift and B) the rear of the towed vehicle being nearer to grounding on rough terrain roads, particularly if it has a long rear overhang..
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ukdave2002
Joined: 23 Nov 2007
Posts: 4114
Location: South Cheshire
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| Posted: Mon Apr 10, 2023 11:23 am Post subject: |
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| Bitumen Boy wrote: | | ukdave2002 wrote: | The dolly must be powered via some sort of PTO, otherwise there would be no point in having tracks?
Possibly for recovery over rough/ soft terrain and or where the recovered vehicle had damage? |
I think the dolly being powered by PTO is a good shout. But if the ground is soft, how is the recovered vehicle to be lifted sufficiently to get the dolly underneath the axle, and how does the tow vehicle not also get stuck? There are more questions than answers with this one! |
Possibly the visible “RSJ” is the end of a crane jib that extends out of the rear to lift the stranded vehicle? |
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alastairq
Joined: 14 Oct 2016
Posts: 1956
Location: East Yorkshire
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| Posted: Mon Apr 10, 2023 12:17 pm Post subject: |
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The dolley looks like an attempt to achieve low ground pressure to me.
The bar, I don't think, is attached to a PTO. It looks like an ordinary 'straight bar', used to achieve a rigid tow, since the casualty's brakes would not be active.
The RSJ extends to the rear to provide a lifting capability.
See link below?
https://www.keymilitary.com/article/trouble-trucks-and-trailers
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Dellow Mk2, 1951 built, reg 1952.
Fiat 126 BIS
Cannon special [1996 registered. Built in 1950's]
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Ford Pop chassis, Ashley 1172 bodyshell, in pieces. |
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ukdave2002
Joined: 23 Nov 2007
Posts: 4114
Location: South Cheshire
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| Posted: Mon Apr 10, 2023 1:55 pm Post subject: |
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| alastairq wrote: | The dolley looks like an attempt to achieve low ground pressure to me.
The bar, I don't think, is attached to a PTO. It looks like an ordinary 'straight bar', used to achieve a rigid tow, since the casualty's brakes would not be active.
The RSJ extends to the rear to provide a lifting capability.
See link below?
https://www.keymilitary.com/article/trouble-trucks-and-trailers |
Thinking about it you are probably right about the dolly not being powered, it would require a lot of additional engineering, a tracked trailer could probably be made narrower and lower that a wheeled dolly, and as you point out spreads the load. |
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Ray White
Joined: 02 Dec 2014
Posts: 6337
Location: Derby
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| Posted: Mon Apr 10, 2023 1:59 pm Post subject: |
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| alastairq wrote: | The dolley looks like an attempt to achieve low ground pressure to me.
The bar, I don't think, is attached to a PTO. It looks like an ordinary 'straight bar', used to achieve a rigid tow, since the casualty's brakes would not be active.
The RSJ extends to the rear to provide a lifting capability.
See link below?
https://www.keymilitary.com/article/trouble-trucks-and-trailers |
I think you are right, Alastair. If you had a PTO attached to a dolly with tracts like that it would be fighting the 6WD lorry unless it had gearing of some kind. |
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consul 57
Joined: 09 Nov 2017
Posts: 488
Location: somerset
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| Posted: Tue Apr 11, 2023 12:15 pm Post subject: |
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the picture is in the book breakdown about recovery in the british army
the dolly is called a tracked ambulance and the austin is breakdown version with an rsj to hang the pulley block from to lift engines and fronts of vehicles for towing suspended or with the un powred dolly, which is from ww2, the pic is from the 50's.
the army experimented with several tracked recovery trailers in pre & during ww2. |
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alastairq
Joined: 14 Oct 2016
Posts: 1956
Location: East Yorkshire
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| Posted: Tue Apr 11, 2023 1:16 pm Post subject: |
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The RAF had a similar idea, with their aircraft recovery dollies.
{ Tracjacs?}
A link to a web page, various excellent photos after scrolling down, plus excellent user-based descriptions of purpose.
https://hmvf.co.uk/topic/9078-tracked-aircraft-recovery-dolly/
_________________
Dellow Mk2, 1951 built, reg 1952.
Fiat 126 BIS
Cannon special [1996 registered. Built in 1950's]
----------------------------------------------
Ford Pop chassis, Ashley 1172 bodyshell, in pieces. |
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