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Bulldozer Question
I know its not really a CMP question but you blokes seem pretty knowledgable about these things.
In have been reading accounts of the British using D4 and D7 Bulldozers. What do these designations actually mean? I presume it is weight or something. Picture comparisons or dimensions would be useful. The reason I ask is I read an account of the British parachuting D4s into the Borneo Jungle and as a model maker thought it might make an interesting diorama. However in 1/35 scale I can only find the resicst D7. Would it be feasable to parachute a D7 or are they way too big? I also found a Clarke Airborne Bulldozer, how does this relate in terms of D rating? Thanks Paul |
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Clarks
Well size-wise the Clarks would be about D 0.01 I'd say.
It's just a size theing. The most common was the D2, and as the number got bigger so did the machine. You wouldn't want to pass off a D6 as a D4, no sir. Gordon
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Gordon, in Scotland |
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The early Caterpillers were rated by weight like the "2 Ton Cat". The next ones were the 15 Cat, 20 Cat, etc but they were a bit heavier than the numbers might imply. When they came up with the "D" series they were way heavier.
The USAF tried dropping a D7 out of a Hercules in Vancouver in the 1960s and as the chutes opened they ripped off one by one but the Cat did make it to the ground, albiet in not too good of shape. They've perfected the technique since then!
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1940 Cab 11 C8 Wireless with 1A2 box & 11 set 1940 Cab 11 C8 cab and chassis 1940 Cab 11 C15 with 2A1 & Motley mount & Lewis gun 1940 Cab 11 F15A w/ Chev rear ends 1941 Cab 12 F15A 1942-44 Cab 13 F15A x 5 1942 cab 13 F15A with 2B1 box 1943 cab 13 F15A with 2H1 box 1943 Cab 13 C8A HUP 1944 Cab 13 C15A with 2C1 box 1943 Cletrac M2 High Speed Tractor MkII Bren gun carrier chassis x 2 |
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Those who live by the sword will be shot by those of us who have progressed. - M38A1, 67-07800, ex LETE |
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Seen an image somewhere
Of one they 'chute dropped at the south pole and the chutes failed...
It made rather a large, deep hole, and wasn't in too good condition.
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Gordon, in Scotland |
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Quote:
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SUNRAY SENDS AND ENDS :remember :support |
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When I watched it come out the back of the Herc there was no doubt in my mind that the Cat would make it to the ground! It made quite a thump when it hit and there wasn't much left that was any good!
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1940 Cab 11 C8 Wireless with 1A2 box & 11 set 1940 Cab 11 C8 cab and chassis 1940 Cab 11 C15 with 2A1 & Motley mount & Lewis gun 1940 Cab 11 F15A w/ Chev rear ends 1941 Cab 12 F15A 1942-44 Cab 13 F15A x 5 1942 cab 13 F15A with 2B1 box 1943 cab 13 F15A with 2H1 box 1943 Cab 13 C8A HUP 1944 Cab 13 C15A with 2C1 box 1943 Cletrac M2 High Speed Tractor MkII Bren gun carrier chassis x 2 |
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The D number system is used by Caterpillar to denote the different crawler dozers they make. The wartime D4 weighed about 5 tons, the modern D4 tips the scales at about 9 tons. D7 wartime was about 12 tons, modern D7 is more than twice as heavy at 26 tons. I doubt that D7s could be air dropped. D4 was 62 in. wide, 122 in. long. D7, 98 in. wide, 162 in. long. Lengths are to end of drawbar.
Perry Last edited by pkitson; 08-09-07 at 21:57. |
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A few years ago
the RNZAF were tasked to drop a dozer (don't remember what size) on to Pitcairn Island. They had a dropzone about the size of rugby field.
Mission was accomplished successfully, but there is a whole lot of empty Pacific Ocean round that wee island. Rob |
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D Series
Just as a point of interest the "D" in Caterpillar stands for Diesel or so I'm told.... The 1931 "Diesel 60" motor built by Cat became the staple heavy machine engine used in the USA at least.
The number designated size as already mentioned.. The 1942 RD-1820 radial diesel engine was used to power the M-4 tank with the "RD" prefix standing for Radial Diesel..
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Mallee Wombat |
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Re: D Series
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Alex Blair :remember :support :drunk: |
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Herc
The civy Herc we were using had a usable load of 20,000kg well below 26tons for sure. Can the military ones carry more as they may not have the same weight restrictions or was the D7 dropped out of something bigger?
Sean
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1944 Allis Chalmers M7 Snow Tractor 1944 Universal Carrier MKII M9A1 International Halftrack M38CDN 1952 Other stuff |
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Getting back to pauls question about parachuting into Borneo - I would not have thought that was achievable in the 1940s. In 1944 there was only limited success parachuting Jeeps.
As to sizes & weights this from the Trux web site Quote:
I know that a few Clark Airbourne dozers were used by the british in Europe but were landed by glider Think the same was true in Borneo Noel |
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Weights of tractors
Looking at the two posts above, it appears that a WW2 vintage D7 (tractor only) could have been transported and possibly dropped from a Hercules. Most construction machinery gets heavier over time for the same model name as part of the competition to say "my toy is better than yours". Current production D7 weighs between 56 and 60 thousand pounds (operating) or 46 to 50 for shipping. Horsepower is now quoted as 240. Quite a change from the earlier versions.
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Between the 60 and the D6 there was the RD6 so it could have been around 6 tons. The designation numbers likely originated based on the actual weights but as stated above the weights got heavier over time.
All I know about the Herc's payload is they could lift a D7. The newer versions could likely heft a little more. Here's a pic of a wartime D7 and a Clark airborne dozer in approximately the same scale. This is a lot like comparing pigs and chickens!
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1940 Cab 11 C8 Wireless with 1A2 box & 11 set 1940 Cab 11 C8 cab and chassis 1940 Cab 11 C15 with 2A1 & Motley mount & Lewis gun 1940 Cab 11 F15A w/ Chev rear ends 1941 Cab 12 F15A 1942-44 Cab 13 F15A x 5 1942 cab 13 F15A with 2B1 box 1943 cab 13 F15A with 2H1 box 1943 Cab 13 C8A HUP 1944 Cab 13 C15A with 2C1 box 1943 Cletrac M2 High Speed Tractor MkII Bren gun carrier chassis x 2 |
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Thanks for all the imput.
The picture is from the Royal Engineers Museum in the UK. It shows a static display of a D4 Bulldozer on a medium stressed platform dropped by parachute into Borneo from a Beverley Transporter so it must be 1950s or 60s. My question was could they deliver a D7 via the same route? |
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Airdropped
The C119 Boxcar can lift 20,000lbs I believe . So it could have handled the D4 no sweat. Did the Brits use this aircraft also?
Sean
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1944 Allis Chalmers M7 Snow Tractor 1944 Universal Carrier MKII M9A1 International Halftrack M38CDN 1952 Other stuff |
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Quote:
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Quis custodiet ipsos custodes? |
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Lapes
Indeed there was an aircraft lost with all aboard while conducting LAPES at CFB Namao, late 70's early 80's? due to the load hanging up after the chutes had deployed however, I beleive that the system is still practiced today.
Needless to say, that even from the ground LAPESing is a sphincter tightener. Cheers
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.50 Cal Ammo Can |
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Lapes
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Quote:
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Richard 1943 Bedford QLD lorry - 1941 BSA WM20 m/cycle - 1943 Daimler Scout Car Mk2 Member of MVT, IMPS, MVG of NSW, KVE and AMVCS KVE President & KVE News Editor |
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Quote:
(P.S.) Hmmm, it's not allowing me to upload a picture of several grunts manhandling a D4 into a Skytrain. Oh well, these days I'm happy to simply be able to post a reply!
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Quis custodiet ipsos custodes? |
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I'll try the upload for you Derek
Here goes...
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Film maker 42 FGT No8 (Aust) remains 42 FGT No9 (Aust) 42 F15 Keith Webb Macleod, Victoria Australia Also Canadian Military Pattern Vehicles group on Facebook https://www.facebook.com/groups/canadianmilitarypattern |
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Too big for a D4
Thanks Kieth, much appreciated! Y'know, after taking a good look at the dozer being loaded into the C47 in this pic, it's too small to be a D4, I wonder if it's a CA-1?
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Quis custodiet ipsos custodes? |
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bulldozer
Hi First I will say that the older cats pre 1936 numbers stood for horse power .A 30 cat had 30 HP a 60 had 60HP .The 35 was the first deisel .The R series were R being a gas ,RD is a deisel The RD 2,4,6,8 and some U series were the Catipiller modles used in the ww2 .I put a D7 in a Hurculies aircraft in Yellowknife where it was hauled to the artic we had to remove all the dozer parts ,blade and C frame maily because it was too wide ,not too heavy .I might add that these cats did not have canopies on them and when working in the bush kild alot of operaters from the tree tops comming down on them .Some were sheeted in with iron and used in combat They were so reliable that they made a great impact on the out come of the war George
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George is hooked on OD 5 window DT969 8 ton Fruehauf trailer M2A1Halftrack ,CMP #11 F15A1 #13 F15A1 RAF Fordson Tractor, 42 WLC HD No.2MK11 CT267514 center CB24713 bottom hull25701 ,No.2 MK2 parts MK1 10128 ,(2) MK1 ,Parts Hull9305 .Hull 10407 Hull plate # 7250 all have walk plate on back steps 1917 Patent modle amphibious army tank |
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Keith,
I agree with Sapper that it is a little baby Clarke air portable tractor. |
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Quote:
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Quis custodiet ipsos custodes? |
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Derek,
I will ask Bev about them as she keeps a daily diary of our travels but the chance of getting "Sighted Clarkair bulldozer" in her usual couple of paragraphs over "Sighted two squirrels and beautiful wildflowers" does not make me wildly optimistic about a result. One, I am pretty sure was on I-90 going west from Minneapolis about mid-morning - it was actually sitting in a little landscaped garden at the entrance to the company yard. The second one was in the Black Hills area of South Dakota on a pole in a small town, but which one??? Sorry to be so little help but I have to curb my hunting instincts when overseas. Lang |
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Quote:
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Quis custodiet ipsos custodes? |
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Identification
I know which were the main types of dozer/tractor used by the British forces in NW Europe - How would I identify the type from a picture? - that is how would I distinguish a Cat D4 from a Cat D7 from an International ? And what other types were used by other Nations? |
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