Sd.Kfz.138/1 Grille

UM Kit #: 346 Sd. Kfz.138/1 M
Revell Kit #: 3315 Sturmpanzer 38(t) Grille Ausf. M (former unreleased Toxso Models kit)

Preview by Stephen 'Tank Whisperer' Brezinski - sbrez1(at)comcast(dot)net
Edited by Rob Haelterman

A Tad Bit Of History (What’s In a Name?)
Above in the review title I use the names given by the model kit manufacturer. For brevity I will used the term “Grille” in this model kit preview. According to Jentz & Doyle, the official name for this self-propelled infantry gun was SF mit S.I.G.33 auf Fahrgestell Pz.Kpfw.38 (t) (Motor Mitte) Ausf. K Geschuetzwagen 38 fuer sI.G.33/2 (Sf) (Sd.Kfz.138/1), or “Grille”. In Nielsen’s book he uses the term 15cm Infanteriegeschütz 33/1 auf Selbstfahrlafette 38(t)(Sf) Ausf. M (Sd.Kfz. 138/1). I understand Grille to be the/a common name which translates to “Cricket” in English. Jentz & Doyle in 2002 clearly states “The name Bison was never used during the war for the 15 cm s.I.G. auf G.W.38: its suggestive name was “Grille”.

In contrast, the assessment of Joachim Engelmann in his 1992 book is: “Despite the frequent confusion as to type names, this gun never officially was called “Grille” (Cricket). Foreign assertions are incorrect. On the basis of its chassis, it is basically a member of the “Marder” (marten) family…” In his book Engelmann refers to the 15-cm s.IG.18 mounted on the Pz. I, the Pz II, the Pz III and on the Pz.38(t) all as the “Bison”. I have seen online the term Bison being used with the self-propelled sIG33 guns: the Sturmpanzer I Bison and Sturmpanzer II Bison, and if you see it on the internet, it must be true? Engelmann has quite a respectable list of publications on German AFVs and artillery but I also know and trust Jentz & Doyle and their research from original German documents so will accept their and Spielberger’s decision to call these Pz.38(t) based vehicles Grille or Geschuetzwagen 38 Ausf. K.

The vehicle is a self-propelled 15-cm infantry gun, a short-range howitzer-like weapon that fired a powerful high explosive shell in direct support and control of the front-line infantry. A previous Grille version had a large high superstructure atop a new or rebuilt Pz 38(t) chassis. This variant had a redesigned hull and superstructure initially developed for the Panzerjäger 38 Ausf. M and modified for the 15-cm sIG33 with the engine installed forward next to and behind the driver compartment making for a better-balanced vehicle and crew performance.

UM kit 346 Sd. Kfz.138/1M boxart depicts an accurate Grille in a cold winter setting. The gun is at a high elevation with a hinged armor flap underneath. In front of the gun is the travel lock which could be folded down when the gun is in action. Superstructure construction is riveted. On the bow we see a new sloped glacis with angular welded driver’s hood of the Ausf K chassis; the Marder III on the same chassis was seen with a cast driver’s hood. On the lower port-side we see the engine air intake with the engine exhaust pipe that goes to the muffler mounted on the rear. Below the fenders is the old Pz.38(t) leaf spring suspension system and large roadwheels. The sprocket and idler wheels are the original type common to the Pz.38(t). The kit name on the boxart is Sd.Kfz.138/1M Bizon (Bison), following Engelmann’s naming.

Not officially being reviewed because I do not have one, but deserving of an honorable mention, this is the short-run injection-molded Attack Hobby kit that I believe is no longer in production at this time in 2021 but still seen in collections and on eBay, etc.. The kit has 88 parts and a small etched metal fret. Some plastic parts go unused. Based on the extended hull sides with towing eyes and the sprocket wheel this is a late production Geschuetzwagen 38 Ausf. K. Assembly of this Attack model appears similar to the UM model though being short-run molding the parts are often softer edged and with more flash and sinkholes. A kit like this can offer an easy, more rugged model than the Revell kits for a wargamer, but on the other hand offers more fun and challenge in detailing and improving the parts to make a display model. The model and others were released in 1/72 long before anyone else and I thank Attack Hobby Kits for that.

Revell kit 3315 Sturmpanzer 38(t) Grille Ausf. M and Revell kit 3316 are formerly unreleased Toxso Models kits and all new tooling, not a former Italeri or ESCI kit. The gun travel lock is portrayed folded forward. On this and the UM boxart we see spare track links mounted on the bow and glacis. The driver’s hood is welded plate rather than cast. The sprocket wheels appear to be a later style seen on the Hetzer which was produced at the same time as this vehicle. This model kit represents the later Grille variant while the UM model represents an initial production. What makes this a late Geschuetzwagen 38 Ausf. K vehicle are the towing points built into the side-hull extensions, the welded lower hull parts and the late style sprocket wheels.

The camouflage scheme looks quite complex to duplicate on a 1/72 model but the only marking is a simple cross. The model’s name “Sturmpanzer 38(t) appears to be a misnomer as this lightly armored self-propelled gun is unlike heavily armored Sturmpanzers like the Sturmgeschütz III and Sturmpanzer IV Brummbär. I make no claim to be an expert, but this was certainly not an assault, or storming, vehicle to assault a position but should stay in the background and provide artillery support from a distance.

The Kit Parts
UM kit 346 Sd. Kfz.138/1M boxart contains 126 pale gray injection-molded styrene plastic parts for the vehicle plus an additional 54 injection molded plastic link & length track parts. There is a small etched brass fret with five parts. There are no cast resin parts and no crew figures included. Parts are well molded with little significant flash but a few sinkholes. The parts are not slide-molded so the hull will be assembled from multiple parts and the gun muzzle (part 42D) will need to be drilled open. Many parts and sprues are the same as in the UM 1/72-scale Marder and Pz 38(t) model kits and we have extra unused parts.


UM kit 346 Sd. Kfz.138 Sprue-B is common with the UM Marder III M, kit 344 and holds the lower hull and superstructure parts. It looks like the roof (part 138B) has the welded driver’s hood with no hatch, but the welded driver’s hood with round hatch is a separate part (part 28C) allowing for a choice of the welded or the cast driver’s hood (part 81B); UM likes modular kits and reuses sprues for multiple variants. There is an etched mesh screen (part-57E) that goes around the muffler (part-292B) however in reference photos I have seen this screen used on the Grille once, but I have seen the screens on the Jagdpanzer 38 Hetzer and the Panzerjäger 38 Marder III. Revell’s kit has no protective screen for their kit muffler.

UM Sprue D at left holds the s.I.G.33 gun parts and is common with UM kit 345. Sprue-C is particular to this kit 346. I notice that on this kit there are unused parts for which UM fails to give part numbers in the instructions; I counted at least five unused parts in these two sprues. Looking closely at the gun barrel part 42D I see significant sinkholes near the gun breach to fill in and sand smooth. Rivet detail on the exterior of the superstructure is done well, but there is no rivet detail on the interior surface. There are wide sinkholes on parts-27C and -54C, the lower superstructure sides, to fill in.

UM’s Part-80C above is the deck area the gun mounts to and compares with the rear of Revell’s part-A8. Based on the available interior photos the long edge of this UM part should be narrower and more pointed like on the Revell part-A8. UM’s part resembles more the gun deck of the Marder III and may be just taken from UM’s Marder III kit.

Here is one of the two Sprue A holding the wheel, suspension and track parts which is common to other UM Pz.38(t) based kits. For comparison, we have the same type of sprocket wheel done in dark gray cast resin (OKB set 72311). The UM link & length hard plastic track is done very well and was among the best available in small scale until the Revell Marder III and Grille kits, and until the dark gray color OKB resin track sets at right in this photo. The two MG37 ball-mounted machine guns will go into the parts box.

Revell kit 3315 Sturmpanzer 38(t) Grille Ausf. M has about 146 medium gray color, injection-molded, styrene plastic parts. There are no resin nor etched brass parts included. Revell used slide-molding to open the gun muzzle (part D10). The parts are sharply molded with no significant sinkholes, misshapen parts, nor flash. Two crew figures are portrayed in the box art, though no figures are included in the kit. These Revell/Toxso Model kits of the Grille (and Marder III) are all new sprue and model parts and not a reissue of an older model.

Revell’s Sprue-A above holds the hull and superstructure parts similar to UM’s Sprue-B. This sprue is common with the Revell Marder III kit 3316. The photo below of Sprue-A and Sprue-C shows the nice interior surface detail of the hull and superstructure.

In mid construction of the hull there is a significant difference in the way the crew compartment looks, though this may be due to different assembly and the compartment overhang (parts-C15, C22, C23, C25, etc.) being separate pieces on the Revell model. Both models look pretty similar at this point. I do notice that the driver’s hatch on the Revell model in notably larger than UM’s model.

The above photo shows the good interior detail of the hull and superstructure parts, much of this rivet and panel detail is missing from the UM Grille model.

Above left is Sprue-D holding the 15-cm infantry gun parts with open muzzle of the gun barrel (part D10).

Here is a comparison of the mostly assembled s.I.G.33/2 from the UM Models kit in pale gray color, and the Revell kit in medium color gray. The UM gun consists of 12 injection molded plastic parts compared to 27 parts for the Revell kit gun. The difference in number of parts shows in the more accurate Revell gun. The white parts on the UM piece are scratchbuilt changes and detail I added to improve the model, using the Revell gun and reference photos. The Revell gun has an obvious hole on the bottom of the gun carriage so it can be accurately traversed (5 degrees left or right) on the model; the UM gun is designed to glue to the deck and not traverse. The traverse & elevation wheel parts, and the breach area on the UM gun have been significantly rebuilt; compare this with Step-8 of UM’s instructions.

With both of these guns there are so many small parts is was agonizing to keep all the parts from sagging, installing crooked. The breach lever atop the Revell gun was improved with a handle, while the breach handle for the UM gun had to be built from scratch. The two long rods on each side of the gun cradle are hydraulic cylinders for counterbalancing the gun elevation. The weapon could be elevated to 72 degrees so it could function like a 15-cm mortar.

Loosely installed in the partially assembled models we see that the counterbalancing cylinders do not rest on the deck below. Note the model putty over ejector pin marks on the UM model. The breach of the UM gun was drilled out. A big plus of the Revell gun is that the breach can be modeled open.

The two Sprue-B are also common with the Revell kit 3316 and hold the Pz.38(t) wheels leaf spring suspension and long band track that is supposed to bend around the suspension, so no fidgeting with individual links around the sprocket and idler wheels. I found the exceptional Revell track detail only surpassed by the OKB aftermarket resin track.

OKB offers aftermarket cast-resin track and sprocket wheels which will offer a little improvement over the very good Revell parts. The Revell and OKB sprockets here are a later type seen on the Hetzer and this Grille which were in production at about the same time. The OKB resin sprockets appear to be a millimeter or two larger in diameter than the Revell sprocket wheel. I hope that will not be a problem. Revell pale-gray plastic tracks are among the most realistic in smallscale only surpassed by the darker gray OKB resin track.

Assembly Instructions

The UM kit offers a good parts diagram and clear step-by-step instructions that I find a bit cluttered and need to be well studied. The Revell instructions are expanded into more and larger steps, and printed in multiple colors on glossy paper. Both UM and Revell have multiple-view drawings showing painting and placement of the water-slide decal markings.

In order to keep from breaking and losing parts, I recommend ignoring the instructions and adding many of the small detail parts such as muffler and ammunition after the model is assembled. Note that up in the upper left corner of Step-12 we find the little jig part 21C for bending the brass part-100E to form the rain guard over the radio, similar to how they form the track skid atop the UM Model’s M4 Sherman kit suspension bogies.

UM offers a plethora of decal markings but many are not used with this model kit. The small etched metal fret carries various parts such as the fender storage box (part 58E) and some fender braces. The decal sheet gives recognition that this vehicle is called both Grille and Bison. It is odd that the side views appear to show two return rollers per side when in reality the kit and real vehicle only has one return roller per side. The etched brass fret, I believe, is similar to many of UM’s Pz. 38 based model kits and has the number 345 on it which is the kit number for their Ausf. H Bison kit.

Assembly of the Revell kit hull and suspension is very similar to that of the UM kit. I am so glad that both UM and Revell chose to go with individual wheels and separate track rather than go with the one-piece quick build suspension. There is a significant error that is fortunately not difficult to figure out. In Step-5 and Step-6 Revell instructs us to install the eight roadwheels (parts B10) on the wrong pegs (axles) of the four leaf spring bogies (parts B1). The roadwheels will only fit on the outer, smaller, pegs.

The camouflage scheme depicted for the two “unknown unit” vehicles should be a challenge in smallscale but will look great if done well. The small decal sheet has just four variations on the Balkenkreuz. A nice attention to detail in the diagram is the track sag over the single return roller.

In my opinion, within the box these two models look like well designed and produced model kits. They compare well in size and appear to reliably be 1/72-scale.

I purchased my UM Models, OKB and Revell Model products at Tracks & Troops


From an old Aberdeen, Maryland, display, looking forward and up at the gun breach (with firing mechanism removed), gun cradle and gun carriage, and vertical 15-cm shell storage at right. The hydraulic counterbalancing cylinder is in the center foreground. At upper left is the location of the gun sight.

This is the left rear of the interior showing the location of the radio equipment held within a metal frame with triangular rubber dampeners for vibration. Above the radios is what appears to be a storage box for a shell casing. To the right is a vertical holder for a 15-cm projectile. At lower right we see the end of a hydraulic counterbalancing cylinder, and notice that it does not touch, or is mounted to the deck as I have seen some modelers build it. At far left the rear door has been folded down and we can see the edge of the ready rack for three projectiles.

  • Panzer Tracts No. 10 Artillerie Selbstfahrlafetten, by Thomas Jentz & Hilary Doyle. (2002)
  • Panzers 35(t) and 38(t) and Their Variants 1920-1945, Walter J. Spielberger, Schiffer Military History (2008)
  • Panzerkampfwagen 38(t) Variants, Donald Nielsen, Zimmerit Press (1999).
  • BISON German Self-Propelled Artillery in World War II and Other 150mm Self-Propelled Guns, Joachim Engelmann, Schiffer Military History (1992 English publication)

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Article Last Updated: 04 July 2021