The Mörser 18 was designed to replace the World War I-era 21cm Mörser 16 (for 1916, the year of its introduction) which ironically was still in use at the start of World War II. The gun’s design was carried out in secret because of the restrictions of the Versailles Treaty, hence the designation 18.
The gun design itself was nothing innovative and imitated earlier designs. However, the carriage was likely the first production design using a dual-recoil system to increase accuracy and ease-of-use. The barrel recoiled normally in its cradle using the damping cylinder mounted above the barrel and attached to the breach. In addition, the whole top carriage (the barrel and its cradle) recoiled across the base or main part of the carriage. This required two cylinders mounted to the carriage frame and attached to the cradle. The system damped-out the recoil forces and made for a very steady firing platform. The same carriage technology was also used with the 17cm Kanone 18 in Mörserlafette
and the 15cm Schnelladekanone C/28 in Mörserlafette
The Mörser 18 was an enormous weapon, and had to be transported in two pieces: for travel the barrel was towed in its own trailer (one of the references provided below shows the assembly broken down for transport). The box art shows the weapon being transported intact behind what might be a SD.Kfz.8. However, this was only done over very short distances. One vehicle used for transport was a Mörserzugmittel
(“medium mortar truck”). There is a 1/35 kit of this vehicle by CMK that I found on e-bay and ordered. I’ll post a review and pictures later.
The carriage also mounted an integral firing platform that was lowered to the ground when emplacing the gun. The wheels were then cranked up off the ground. A rear castor-wheel jack was used to raise the rear spade off the ground if the gun needed to be traversed more than the 16° allowed by the mount proper. The reference noted above actually shows a crew preparing to lift the rear of the whole unit in preparation for such an operation, or perhaps for attaching the limber.
Just over 700 of the pieces were completed by the end of the war, with none manufactured in 1942 when the emphasis was on the smaller 17cm Kanone 18 in Mörserlafette
The kit comes in the standard open-top cardboard box with the sprues packaged together in pairs in sealed bags, and consists of over 400 parts including:
11 unique sprues with two duplicated for the usual suspension bits
Two large tires and two small tires
Two copper tubes
One Photo Etch fret
Two carriage sides – wrapped in foam for protection
There are no clear parts, or decals.
Several parts are listed as unused. I would suggest removing these to the spares box before starting, so there’s no doubt when a sprue has been completed.
The instructions consist of a 24 page booklet, with 25 steps. In general, the instructions are clear and well-illustrated. However, parts locations are indicated by arrows that lead from a part to its placement, and are sometimes misleading or ambiguous. I often found it necessary to look ahead to find an illustration that shows the part in place.
The kit parts are very well-detailed, and have virtually no flash or seam lines. However, as I understand is common with Trumpeter, there are many ejector pin marks, some in key places. The pictures show a couple of these. Unfortunately, I didn’t putty and sand some of them before assembling, making them difficult to hide. There a lots of VERY small parts in this kit, which adds to the detail, but makes for a very laborious build. So far, I haven’t lost any (the pictures show a few of these, relative to a dime),
The build consists of three major subassemblies:
The cradle and barrel
The carriage is the largest and most-detailed assembly. It covers the first 14 steps (of 25) of the instructions, as well as Step 23. It is critical that at Step 3 the carriage is squared and not lopsided. There are some truly tiny bits that are added, not always easily. For example, I would suggest that the H20 pieces be added to pieces A1 and A21 when those are added to the carriage sides.
The instructions imply the gun can be built in either travel or combat mode, but that doesn’t appear to be the case. The circular support can be stored in travel mode, but that’s as far s it goes. The instructions for the “cat walk” (see pictures) say travel mode, but are actually combat mode, with them perpendicular to the carriage, not vertical. In combat mode, the carriage is supported on the circular base, with three or four wheeled jacks allowing the whole unit to be rotated. There are only two of these jacks provided, one in travel mode (short) and the other in combat mode. Some scratch building is called for here.
The springs provided are a nice touch, but are a bit large, and don’t fit well. Looking at reference photos, they are more tightly coiled than the actual ones. Actual battle pictures also show these covered with a tubular canvas “sock” which probably was meant to avoid inserting arms and legs.
The cradle and barrel take only five steps. Some of the ejector marks show up here. There are lots of cranks and wheels attached to the cradle, which might best be left for the painting phase. Again, making sure this is square is critical, or the gun will point askew.
The limber is nice little kit unto itself. There’s some tricky PE bending here, with only a picture in the instructions to help.
painting & finishing
Pick your favorite monochrome German paint scheme. The instructions call for “dark yellow”, but most photographs seem to be grey. I used the dark yellow, because I have a ton of it.
Comparing various assemblies to the references mentioned below this appears to be a well researched and accurate representation of this interesting weapon. So far, this has been a fun and interesting build, due to the plethora of detailed bits.
A.) Google provides lots of references for this subject, including many with actual in-comabat pictures.
B.) This book by Rossagraph was reviewed here on Armorama
. Unfortunately, the gun shown at the Polish Military Museum is missing quite a few parts, and despite a new paint job, is in bad shape.
c.) Wikipedia shows a Morser located at the Fort Sill OK Field Artillery Museum which sports a very interesting camouflage design. I placed a query for anyone in the Ft. Sill area in the armor forum, and John (Tankrider) responded that he worked there. He took about 50 pictures, and posted them in a Picasa web album