Clarktor-6 and Weaver Bomblift M1

Kit: Academy # 13403 Review Danilo Carli - 172normandyafv(at)gmail(dot)com
Edited by Rob Haelterman


The tractor of the Academy ground vehicle set #4, is the Clarktor-6. Already reviewed by Al Magnus, it is a very small project. Just 25 pieces compose the model. Despite this I found it not so easy to do. The pieces are made from pine green plastic and fit quite well. The only decal supplied is a star for the bonnet top. No registration number or bumper codes are present in the set. This is not a real problem because as far as I've seen most were quite anonymous.
Understanding the right variant depicted by the kit gave me some problems because little info is available. As far as I've found, Clark produced no less than 17 sub-variants from 1940 until the end of production in 1963. A main feature divided the production; the "light duty" type had single rear wheels while the "heavy duty" type had dual rear wheels. The larger mudguards thickness served as a counterweight.
The Academy kit is obviously a "light duty" type, but the fuel filler cap at the right of the seat tells us it depicts a CT21 or CT30, two post WW2 variants built by 1950. Good for Korea, Vietnam and civil aviation (where this tractor saw use up till the 80'es), the Academy variant is too late for my interest.
The 1945 Technical Manual TM 10-1619, from page 126 to page 170 (Chapter 4 -Tractor warehouse) lists 4 variants in service in the US Army: the Standard 24 and the Mill 33 with single rear wheels, the Mill 44 and the Mill 50 with dual rear wheels. Based on the kit model dimensions, to make a WW2 variant, I could only make the Mill 33 because the Standard 24 was 5 1/4" shorter. Making a "heavy duty" Mill 44 or Mill 50, is possible anyway with a little more plastic sheet and another rear wheel couple.
I didn't find the registration number batches list, which first digit was 8 for wheeled tractor.
Examples (heavy duties are in italic) taken from WW2 period photos are 8650, W8735, 81425, W86046, W86807, W87899. Strangely enough, on two Clarktors the registration number didn't start with 8: W3015, 56930.
As far as I've found, also the Royal Air Force received at least 1,512 Clarktors.
Dimensions are quite correct.

1/72 kit

About the wheels, I didn't find the correspondence in the tire chart. The diameter I have calculated should be (diameter x tire section) about 7.6 x 2.2 and 11.2 x 2.7.
Having altered the steering column I don't know how high the model would be OOB, however I could adapt mine to the correct height.
During its longtime military and civil career, the Clark tractor saw local modifications, so different features can be seen in photos regarding the shield, the bonnet, the steps, the seat, the wheels and the pintles. In this perspective, tires apart, the Academy kit can't be seen as a totally wrong kit and it could depict a single specific tractor. But I'm not a post WW2 civil vehicle modeler...
Helped by the limited info and photos I found, here is what I made to improve my WW2 airfield tractor.

    1/72 (mm) kit (mm)
99 1/4" 35.0 35.8
52" 18.3 18.6
Height ** 58 1/2" 20.6
see text

58 7/8"

20.8 21.4
Wheel (front)
6.00x9 see text no
Wheel (rear) 7.50x16 see text 10.0x2.5

* without the pintle.
** to the top of the steering wheel.



  • One of the major faults of the kit is about the wheels. I turned them inside out because their outer side is shallow and then I reworked them to make the rim closer to the originals. They are still not perfect, but they looked greatly improved to me. I filed off the hub from the rear ones and gave them the raised part of the rims from punched 0.5 mm plastic sheet. Then I made the spokes from 0.5x0.5 mm plastic rod. Rounded plastic rod slices were used to make the hub and the bolt heads. The front ones had the tires filed to have smooth sides and the hub sanded down as much as possible. A new hub was created from rounded plastic rod slices.
  • The ejector pin marks present on the underside were filled.
  • The four leaf springs are made as solid "D" shaped items instead of metal bows. Their top was filed to give them a more likely look.
  • I added the steering gear from stretched sprue.
  • The missing exhaust piping was added on the opposite side following the layout suggested by Al Magnus’ civil postwar model. In the better tradition, I find a photo of the original WW2 layout just after having painted the model. I corrected my model; the new muffler was placed just behind the rear bumper in the place of the huge member. I couldn’t remove the second muffler, which became a rounded shield added locally.


  • Absent in the few period photos I've seen, the piece O16 went in the spare box. Their interlocks on the right fender were closed.
  • The ejector pin marks I could reach were filled.
  • I closed the empty space under the seat with thin plastic sheet. Here was the fuel tank in the post war variant.
  • The shield O28 is not correctly depicted. I removed the strip because it is missing in every WW2 period photo I've seen. For the same reason I closed also the bottom edge notch. As correctly pointed by Al Magnus, the number of holes is wrong. A column is missing on both sides as well as three rows too. Unfortunately the shape and the hole dimensions don't allow adding the missing holes. Anyway, there is space for four holes below the bottom row. I drilled them as well as the two holes for the removable hooks. This gave it a more likely look. The thickness was thinned along the edge. This job didn't give me a perfect piece and a photoetched part would be a better option, but the only one I've seen (in the Eduard set # 22111) is not correct either.
  • The two thick supports behind the shield moulded on the fender top were replaced with thin plastic sheet.
  • The bonnet top has an engraved edge which I didn't understand and misses the sides. I filled the gap and made the lateral panels from plastic sheet. I opened the squared windows just to close them by a metal PE mesh (a bit wide anyway). The lights (O6) interlock was filled.
  • Also the radiator mesh O9 was replaced by the metal one.
  • The lights O6 were placed on the rounded edge in the WW2 period photos I've seen. I cut them off and placed them in the correct position after having filled the interlock.
  • There were two caps on the bonnet top. The first was the radiator one, which was sanded down when I filled the lights interlock. The second one is the WW2 production fuel filler cap. I made both from stretched sprue slices.
  • The steering column base insertion was quite different. I replaced it with stretched sprue and placed it correctly. The column was kept in place by a "V" structure which I made from plastic rod and thin metal strip.
  • On the right side the air filter was simulated with plastic rod.
  • I also added the driver pedals and the hand brake.
  • I removed the post WW2 fuel filler at the right of the seat.
  • I reworked the inner edge of the rear fenders with two 0.5x0.5 mm plastic rod segments.
  • The rear bumper O7 is wrongly shaped. I replaced it with plastic rods. The towing hook was replaced by the unused piece O4 adapted for the new placement. The new bumper also corrected the length.



Bomb lift M1

The same tractor mould also has the five pieces which compose the Weaver Mfg Co. Bomb lift M1, catalogue number G189. It was a 3 wheeled cart, which was towed and steered by a T-handle by the ground crew just like a pallet jack. It had a hydraulic platform raised and lowered by two foot pedals (the long one raised it, the short one lowered it). It could lift bombs up to 900 kg (2,000 lb) under the aircraft fuselage and wings.
The Academy body is solid and the T-handle has a solid ring that left me thinking it could be towed by the tractor. The platform shape is wrong. The lifting gear details are shallow. The pedals are missing and the T-handle is incorrect.

This time I found no more info and also the restorer community doesn't look very interested in this item. I didn't find its real dimension, so I cannot give assurances that the scale is correct.
Using just photos, I tried to improve the cart.

  • The first thing I did was to hollow the body, then I made the new platform and the "L" shaped front member. In the mid of the platform there were three holes. I drilled them open (a bit larger I think).
  • I made the lifting gear from plastic rod, stretched sprue and a thin metal wire wrapped around a stretched sprue segment to make the coil spring.
  • On the front I added the pedals from 0.5x0.5 mm rod and thin plastic sheet.
  • On the rear axle I added the trapezoidal sheet and the towing point.
  • The T-handle was replaced with stretched sprue. I left it lying on the ground slightly turned. An optional position can be achieved turning it 180° and leave the T-handle laying on the platform. The thick washer O5 went in the spare box. The new steering insertion point was made from plastic sheet to which I added the bolt heads made from stretched sprue slices.


Looking at the improvements that are required, it can't be seen as a kit for beginners. It is a pity, because both are very nice pieces to add on the concrete runway of an airport. They need important surgery if one is finicky like me. The wheels need to be replaced (as already pointed out by Al Magnus; the front ones are simply horrible). A correct PE piece for the shield and another for the platform would be a great help. A great feature of this kit is the wide period during which both pieces can be used, from WW2 until the modern jet era.

This model can be purchased from Tracks & Troops

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Article Last Updated:
01 August 2021