'Mule' deck tractors in 1/72 scale



I have only a few Verlinden kits, but my favorite of those is definitely the MD-3 'Mule' US Navy tractor. I find the simple design cute in a way that I cannot describe accurately. Quickly I found out that there are many more 1/72 Mule kits, and on this webpage I compare the various models. At the end of the page, a set of reference photos are presented, showing more variations of the APUs mounted to the Mule's rear side.


Designations

My limited understanding of the vehicle's designations is that the original yellow-painted Mules were designated MD-3, MD-3A and MD-3B, and that the improved (Service Life Extension Program, SLEP) white-painted Mules are designated A/S32A-31, A/S32A-31A and A/S32A-31B. The SLEPed version can be identified easily by the widened rear of the vehicle (some 6 inches) and a sloped rear edge (like a car 'spoiler'). The Verlinden, Fujimi and Maquettes Dauzie Mules are the original version, only DreamModel offers the later wider version.

Note that there was a short period where the 'old' version was painted white, because the Navy phased out the yellow paint that contained lead (or maybe cadmium?). Judging from the occurence of both versions in Verlinden's 'Lock-on No 14: USS Forrestal' from 1991 (possibly the contents were photographed in 1990), the switch occured around that time.

All kits I've seen have single rear wheels. But I'm sure the real thing has double wheels. Possibly the 6 inch widening also has to do with the rear wheels, creating a wider track, or the use of wider tires.

Confusingly, the US Air Force also has an MD-3: "The MD-3 Generator Set is a portable unit designed to furnish AC and DC electrical power for the starting of aircraft, and for ground maintenance". It's definitely not a tractor, so the two can't be confused.



History

The Mules used to be known as MD-3s, but are now officially known as the A/S32A-31. I found a few Navy manuals with some information.

Quoting from 'Aviation Support Equipment Technician (ASE 3&2 AND ASM 3&2), Volume 1, Basics' (NAVEDTRA 103245), 1981 edition, page 6-5:

Quoting from'Aviation Support Equipment Technician (ASE 3&2 AND ASM 3&2), Volume 1, Basics' (NAVEDTRA 103245), 1981 edition, page 6-25:

Quoting from NAVAIR (Naval Air Systems Command) 19-40-44:

NAVAIR (Naval Air Systems Command) document 19-40-44 lists the following dimensions, without stating whether it's for the original design or the SLEPed version:



Verlinden

In 2000 I obtained a Verlinden 1/72 resin scale model of the MD-3 'Mule' US Navy deck tractor (catalog number 240, later 2560) at an IPMS meeting. It had been on my wish list for a long time, but I never saw one before. It's shown in my oldest Verlinden catalog, 'Catalog No.4', that's probably from around 1987. It was produced until at least 1994, since it was still listed in Verlinden catalog #13 1994-1995. Verlinden also has a fire-fighting version, kit number 267 (later 2591). The package attached to the rear of the tractor is probably the SB/TAU-2 as described above. It appears that this kit only contains one version, but not having seen the kit, I'm not 100% sure.

The photo below shows all resin parts. At the front there's the 'short' tractor in one piece. The second row shows three rear side attachments, plus five detail parts (two hitches, parking brake handle, steering wheel, hitch extension). The third row shows the front and rear wheels. Also included in the kit are dry transfers, that probably stopped working years ago. Not included is the flexible hose for the APU.

Apart from some pinhole air bubbles, I liked the model a lot. The only thing I planned to improve were the wheels, since the tires lacked profile, which is a bit awkward for such a slippery working place, plus the rear wheels should be dual wheels. I plan to use the wheels of a Fujimi Mule.

In 2021 I gathered some 30 snapshots from various YouTube videos, shown at the end of the page. The photos show both the 'short' version, and the 'long' version. The 'long' version had three types of APUs attached. Unfortunately I do not know which is which (see gas turbine versions listed above), so I called them Type 1, 2 and 3. The Verlinden APU attachment looks a lot like Type 2. For the 'short' version, a ballast plate is missing, but funnily if you would cut off the 'bumper' and rotate it 90 degrees, you're 90% done. Also, a simpler tow coupling is missing: a simple C-bracket with a pin through it.



Fujimi

Eventually I bought the Fujimi 'Deck crew set' (catalog number 35001), and this turned out to be quite a surprise. With regards to details, this injection moulded MD-3 was a near 100% copy of the Verlinden model! Of course Fujimi had to break up Verlinden's single-piece main casting into several smaller parts, but otherwise the differences were very, very small. The hood has a fold on the centerline (that I have seen in only one photo of the real thing, the rest had slightly bulged hoods), but otherwise it is identical, down to the tiniest details. The Fujimi model also has the incorrect 'rear bumper' for the short version like Verlinden, which further reinforces the impression that the kit is a copy. Alternatively, both Verlinden and Fujimi could have used the same set of drawings to create their models (I've been told that Modell Fan once had Mule drawings). On the other hand, I was quite amazed that it was possible for Fujimi to achieve the same detail level with injection moulding. Another lesson learned!

The Fujimi Mule can be built in three versions, the short version, the version with a 'Huffer' extension similar to Verlinden, and the fire-fighting version that is probably the SB/TAU-2 as described above. The first and second are also found in Verlinden #240, the last is similar to Verlinden #267.

The oldest proof of existence that I found of the Fujimi set is a 1990 catalog, but I don't have catalogs of 1987, 1988 and 1989 (it's not shown in the 1986 catalog). The MD-3 is also listed in my 1994, 1995, 1996, 1997 and 2001 Fujimi catalogs. In 2008 or 2009, the Mule tractor was included in a reissue of on Fujimi's VF-96 F-4J.



Testors

The Fujimi set was also issued by Testors in the USA, with catalog number 850, with photo box-art. Possibly it was also sold bagged, with a black and white header card based on the Fujimi box art.



Maquettes Dauzie

In 2007 I bought a Maquettes Dauzie resin 1/72 scale US Navy tow tractor (catalog number 72 006) at the IPMS-NL Nationals. The oldest reference I found so far is an August 1986 advertisement in Scale Aircraft Modeling. Compared to the Verlinden/Fujimi MD-3, it has a different unit attached to the rear side. Also included are parts to make the air starter's hose, in the shape of a piece of hose, and metal wire to wrap around it. Judging from the exhaust location on the right side, the APU is like Type 1 in the reference photo section below. However the details on the left side are of Type 2 if I am not mistaken. The same tractor was also available without the APU unit at the rear (catalog number 72 007).

The length and width of the complete vehicle are around 15% less than the Verlinden/Fujimi Mule, which makes you wonder who used the correct (or best) data. I obtained some more MD models, and the dimensional errors in them are so obvious that my trust in MD's master builder has disappeared largely. Therefore I believe the Verlinden/Fujimi Mules are more accurate.





DreamModel

In 2008, DreamModel from China issued four resin Mule kits, with photo-etch details and decals. The versions are old & new short style, and old & new long style tractors. The new style tractors have increased rear track, and slightly widened fenders to match.

0201 (old & long) 0202 (new & long) 0203 (new & short) 0204 (old & short)


PhantomModels

In 2013 PhantomModels from Moscow issued a resin Mule kit, with photo-etch details and decals (catalog number 7002). It represents the updated version with increased rear track, and slightly widened fenders to match.



Hobby Master die-cast

Hobby Master released a diecast Mule in a blister packaging. It comes in two versions: the 'US Navy Tow Tractor' (catalog number HD2002B) featuring an MD-3A with two figures, and the 'US Navy Fire Tractor' (catalog number HD2003B) featuring an MD-3 with the fire fighting attachment, in white and red, with two figures. They two versions are also sold together as 'Modern aircraft carrier diorama' (catalog number HD1002).



Kit comparison

I haven't assembled the Verlinden and Fujimi kits yet, but of these two the Fujimi kit seems to hold the edge. Some advantages:



Colors

Somewhere during the early nineties, the color of US Navy deck vehicles switched from yellow to white. Alex Suvorov's excellent webpage U.S. Navy Flight Deck Tractor Models claims the colors were FS 33538 Orange Yellow and FS 17875 Insignia White. Humbrol 197 and Revell 310 (both RAL 1028 matches) come quite close to the former.



MD-3 'short' tow tractor

Both 'short' MD-3s have what looks like a ballast plate attached to their back sides. They are about half the height of the tractor, with rounded top corners.

Snapshot from video SH-3A helicopters loaded with homing torpedoes are hooked up with tractors aboard
There's a ballast plate on this one too.

Snapshot from video Ready On Arrival (1966)
This MD-3 has a short and simple tow attachment on the front.

Snapshot from video SH-3A helicopters loaded with homing torpedoes are hooked up with tractors aboard
The MD-3 on the right has a long (extended) tow coupling on the rear. The one on the left has a tow coupling (different from the above) on the front.

Snapshot from video SH-3A helicopters loaded with homing torpedoes are hooked up with tractors aboard
Another 'short' Mule with a ballast plate at the rear.

Snapshot from video SH-3A helicopters loaded with homing torpedoes are hooked up with tractors aboard
The ballast plate is nicely striped on this Mule, and it has a long (extended) pintle hook on the rear.

Snapshot from video Tractor tows an aircraft S2F by tail aboard USS Randolph
Another 'short' Mule with a simple tow attachment on the front bumper. Look at the shine on those tires! The overall condition looks near-perfect too.

Snapshot from video Tractor tows an aircraft S2F by tail aboard USS Randolph
Another nicely striped ballast plate, and it has a short pintle hook on the rear.

Snapshot from video Tractor tows an aircraft S2F by tail aboard USS Randolph
This Mule looks brand new to me. In the source movie, the Enterprise looks like it's on shakedown, with only a few aircraft on board. This makes it from the early sixties.

Snapshot from video Inside The Big E


MD-3 with type 1 APU

This APU attachment is flush both on top and on the sides. The circular exhaust is positioned relatively far aft.

Snapshot from video USS Kitty Hawk '70-'71 Cruise (launch/recovery)
A reasonable rear view of the same APU attachment.

Snapshot from video Vought F-8 Crusader - The Last Gunfighter
Another partial view of the right side of the APU.

Snapshot from video US Aircraft take off from USS Coral Sea in South China Sea
A clean shot of the APU's right side. The Mule has a aircraft arrestor hook attached for some kind of cable operation.

Snapshot from video United States Navy, A-7E aircraft being towed across the deck aboard Super carrier
I believe (based on limited data) that this is the left side of the Type 1 APU, with louvers.

Snapshot from video Air Ops - USS Kitty Hawk (CVA 63) - Gulf of Tonkin 1970-1972 (Part 1)
This back view is identical to the second photo of the Type 1.

Snapshot from video A day in the Western Pacific aboard USS Oriskany CV-34 U.S. Navy film 81104
A shot that shows some details of the rear side of the Type 1. It never seems to have the hot air unit attached to it, like the Type 2.

Snapshot from video U.S. Navy aircraft carrier flight deck safety training film "Disasters don't just happen"


MD-3 with type 2 APU (like the Verlinden model)

This APU type has the exhaust more forward compared to the type shown above, plus two smaller black circles at the 45 and 225 degree positions.

Snapshot from video United States Navy, A-7E aircraft being towed across the deck aboard Super carrier
Another one showing the 'three circles' layout of the APU's right side.

Snapshot from video Aircraft launched from flight deck of USS Constellation at Yankee Station
Looks similar to the above subversion.

Snapshot from video Air Ops - USS Kitty Hawk (CVA 63) - Gulf of Tonkin 1970-1972 (Part 1)
Another photo of the type.

Snapshot from video F-4B aircraft being launched from deck of USS Enterprise (CVAN-65) during Vietnam
As far as I know, this is the left side of the Type 2 APU.

Snapshot from video United States Navy, A-7E aircraft being towed across the deck aboard Super carrier
A slightly blurry shot of the APU's left side.

Snapshot from video Air Ops - USS Kitty Hawk (CVA 63) - Gulf of Tonkin 1970-1972 (Part 1)
A shot from the early sixties. Note relatively few markings during the initial use. The Mule at the left has its wheels painted in a different color.

Snapshot from video Inside The Big E
This is probably the same Mule as in the above shot.

Snapshot from video Inside The Big E
In this picture we see a unique detail: a long tie rod that connects the APU to the tow tractor. I'm not sure this is a standard fit.

Snapshot from video U.S. Navy aircraft carrier flight deck safety training film "Disasters don't just happen"
Great detail shot of the APU's right side.

Snapshot from video U.S. Navy aircraft carrier flight deck safety training film "Disasters don't just happen"
Interesting rear view, with some kind of attachment on the rear's top. The Mule at the rear is shown in the Type 3 APU section.

Snapshot from video Operation Saratoga (1965)


MD-3 with type 3 APU

Both Mules have the APU in a 'raised' position, well above the deck of the tractor itself. The combination of the gusset in the tractor's extension and the triangular rear leg of the APU creates the trapezoid shape, that is the easiest identification feature of this version.

Snapshot from video Discovery Channel Wings - A-4 Skyhawk
 
This looks like the same APU unit to me, but now lowered and flush with the tractor. The trapezoid is accordingly lower. However it looks like the APU is wider than the tractor.

Snapshot from video Ready On Arrival (1966)
The left side also shows the trapezoid opening. Again the APU appears to be slightly wider than the tractor.

Snapshot from video Ready On Arrival (1966)
 
Is this the previous deck vehicle that carried the same APU?

Snapshot from video Landing of US Navy jet fighters on flight deck of aircraft carrier USS Franklin
A nice shot of the rear of this APU type.

Snapshot from video F-4B aircraft being launched from deck of USS Enterprise (CVAN-65) during Vietnam
 
Great side view of this MD-3 type. The APU is again wider than the tractor.

Snapshot from video F-4B aircraft being launched from deck of USS Enterprise (CVAN-65) during Vietnam
The Type 3 APU being used to start up an A-4 on board USS Saratoga.

Snapshot from video Operation Saratoga (1965)
The Type 3 APU Mule towing an A-4 on board USS Saratoga.

Snapshot from video Operation Saratoga (1965)


MD-3 with type 4 APU ?

There may be yet another type of APU attachment, or maybe it was a fire-fighting unit, considering it was painted red, plus what look like rolled-up fire-fighting hoses. So far only one picture has surfaced, on the USS Coral Sea tribute site (find courtesy of Jari).



MD-3 various details

This is probably a Type 2 APU with an additional basket. It appears to be made from angle iron and wire mesh.

Snapshot from video The job of the EA-6B Prowler Grumman Aviation film 81802
 
A good view of the dashboard.

Snapshot from video U.S. Navy aircraft carrier flight deck safety training film "Disasters don't just happen"
A rare partial view of a Mule with the SB/TAU-2 firefighting unit.

Snapshot from video A day in the Western Pacific aboard USS Oriskany CV-34
 
Great view of the instrument panel. But what are the vertical tubes? Both Mules have them. Maybe it's to prevent tow bars from falling off - but then the driver is in the way!

Snapshot from video Landing of US Navy jet fighters on flight deck of aircraft carrier USS Franklin


1/72 model links



1/48 model links



1/32 model links



Research links





Return to models page