The Tiger gun carrier
On the 6th of May 1942, the German weapons manufacturer Krupp submitted a proposal for the construction of a new armored self-propelled gun carriage that used components from the Panzerkampfwagen VI Tiger. While it was based on the Tiger tank chassis design, it was radically altered. It was meant to be able to carry two different guns.
The Grille 17/21 chassis is on the right of the photo next to a King Tiger with the early turret and a Panther tank on the far left. Behind the three vehicles is a Jagdtiger SPG. They were all captured at the Henschel Panzerversuchsstation, Haustenbeck Ordinance proving ground. (The Tank Museum, Bovington)
The vehicle was named, in typical German fashion, the ‘Geschützwagen Tiger für 17 cm Kanone 72 (Sf.)’ or the ‘Geschützwagen Tiger für 21 cm Mörser 18/1 (Sf.)’, depending on the gun mounted.
The German word Geschützwagen literally translates to ‘gun vehicle’. This is not an accurate description of the concept behind this artillery self-propelled gun. A gun carriage would be a better description. Unlike other German self-propelled guns, this vehicle was designed to mount different weapons. It was a modular concept. The vehicle was given the shorter names of Grille 17 and Grille 21 depending on what weapon was mounted inside the vehicle. The German word Grille means ‘cricket’ and the letter ‘e’ at the end is pronounced as an ‘er’: Grill-er.
The proposal was submitted on 6 May 1942 to the Wa Prüf 4 artillery division of the Heereswaffenamt (HWA) (German High Command’s center for technical weapons development). Krupp was authorized to build a single prototype with a completion date of 1 November 1942. The Wa Prüf 4 made a requirement that the vehicle must have the ability to have a 360-degree traverse. They also wanted it to be available for coastal defense work if necessary.
The Grille 17/21 chassis was much longer than a standard Tiger tank and difficult to photograph at close quarters. This image has been made by ‘stiching’ together a number of separate images. (The Tank Museum Bovington)
Design and Problems
The two guns were too heavy to be mounted in a turret so the Krupp design team had to find another solution. They constructed a large heavy circular base plate that would be carried at the rear of the vehicle and lowered into position when needed. The SPG would then drive onto the metal plate and could swivel on its tracks to point the gun at the target. This was an unusual design feature of this weapon system not seen on any other German vehicle in WW2.
Another requirement was that the guns were to be dismountable. This would be achieved by driving backward towards the base plate, after which the gun could be slid out of the vehicle and mounted on the base plate, allowing it to cover 360°. The reasoning behind this feature was that the Grille was also meant to be used in the coastal defense role and this allowed it to fire in any direction. This requirement was dropped in 1944 under the orders of Heinrich Himmler.
Design and mechanical problems were also encountered with the Tiger chassis, engine and transmission. It did not help that the winner of the competition between the Porsche and the Henschel designs hadn’t yet been decided, and they had vastly different drivetrain arrangements.
This American officer is examining the engine bay of the Grille 17/21 chassis. His presences gives you the sense of proportion of this weapon. It was very large. (The Tank Museum Bovington)
Initially, the vehicle was meant to have a 30 mm armor plate on the front of the chassis and 16 mm on the sides. In November 1942, it was decided to use SM-Stahl (carbon steel) in the construction of this self-propelled gun. 50 mm of SM-Stahl carbon steel were used for the front of the vehicle. The sides and rear would have 30 mm SM-Stahl carbon steel. This added to the weight of the vehicle. There were a number of delays in the project. The original 1 November 1942 completion date passed without a prototype being finished.
When the Panzer VI Ausf.B Tiger II (Sd.Kfz.182) heavy tanks started rolling out of the factory doors, Krupp decided to use the Tiger II engine, suspension, steering, and transmission instead of Tiger I parts. These components were not ready for delivery until January 1944. This delayed the estimated final construction of the prototype until the summer of 1944.
On 25 September of 1944, Reichsminister Albert Speer ordered a demonstration for Adolf Hitler to take place as soon as the vehicle was completed, now planned for the end of the year. Serial production was to then start at the rate of two per month.
This photograph was taken at the Henschel Panzerversuchsstation, Haustenbeck (Ordinance proving ground). Notice the armored hatches on the front of the Grille 17/21 SPG’s superstructure. (The Tank Museum Bovington)
It was envisaged that two different guns could be mounted in the vehicle: the 17cm Kanone K72 (Sf) L/50 or the 21cm Mörser 18/1 L/31. These two weapons were chosen because they used the same gun carriage and recoil system. The fittings would be the same when the guns were mounted within the self-propelled gun superstructure. The guns would have had a traverse of 5 degrees left and right from a fixed position. The gun sight was a Z.E. 34 with Rblf.36. Both vehicles would have to be supported by a number of ammunition carrying vehicles.
17 cm Kanone 18 in Mörserlafette on display at the U.S. Army Field Artillery Museum, Fort Sill, Lawton, Oklahoma, USA. (Jon Bernstein)
The Grille 17 would have carried 5 rounds plus propellant on board when equipped with a 17cm Kanone K72 (Sf) L/50 gun. It could fire two types of shells, the 68 kg Sprenggranate(HE) with 29.15 kg of propellant and a range of 28,000 meters and the 62.8 kg Sprenggranate(HE) with 30.5 kg of propellant and a range of 29,600 meters.
The 21cm Mörser 18/1 L/31 was already in production and use by the Germans when the project started. It was produced to replace the much older 21cm Mörser 16. The 21cm Mörser 18 replaced the 21cm Mörser 16 in front-line service around 1940 with the older gun being relegated to secondary theaters and training units. More than 711 21cm Mörser 18 guns were produced in 1939–45. The Grille 21 would have carried 3 rounds plus propellant on board when equipped with this gun. It could fire a 113 kg Sprenggranate(HE) shell with 15.7 kg of propellant to a range of up to 16,700 meters.
A 17 cm (172 mm) gun barrel and breach can be seen on the floor in front of a gun carriage with 21 cm Mrs 18 painted on it. The fate of the gun is not known.
In January 1945, plans were made to mount a 30.5cm caliber smooth bore mortar with fin-stabilized projectiles, due to the concerns over the length of time it took to produce artillery barrels for the two other guns. Krupp and Skoda both competed on this project with Skoda producing a 30.5 GrW L/16 prototype by April 1945.
As a side note to armament, in 1945 Kurt Arnoldt, Chief Engineer at Henschel, said in a 1945 interview that the 21cm gun produced too much recoil for the chassis as designed, making it impossible to fire from the chassis. The 17 cm muzzle break was based on a design by Solothurn design. Ammunition would have been stowed both in the vehicle and in wicker baskets on the side of the vehicle as well as in a following 18-ton semi-tracked vehicles (half-track). The gunnery sights also allow for direct firing of the gun on close-range targets.
German 21 cm Mörser 18 on display at the U.S. Army Field Artillery Museum, Fort Sill, Lawton, Oklahoma, USA. (Jon Bernstein)
According to a British intelligence report from 1945, the Grille designs meant to have a crew of 8, composed of a driver, a commander and 6 gun crewmen. The loading of the two-part ammunition was meant to be done manually. It is stated in a 1945 interview with Kurt Arnoldt, the Chief Engineer for Henschel, that the additional crew would travel in a semi-track vehicle, Kurt Arnoldt suggests the 18-toner, and haul additional ammunition.
A Tiger II Maybach HL 230 P30 V-12 water-cooled petrol 690 hp engine was ordered along with a Maybach OG 40 12 16 B gearbox with eight forward and 4 reverse gears. Henschel made the L 801 steering unit. The engine was mid-mounted in the chassis to allow for the maximum amount of room for the large gun and space for the crew.
As rubber was difficult to obtain in 1944 the wheels were 80 cm all steel tires. However, the 1945 interview with Kurt Arnoldt suggests rubber rimmed roadwheels. But photos do not confirm this. It was fitted with Gg 24-800/300 Tiger II track for traveling cross country, but this would have been replaced with smaller width Gg 24-600/300 Panther II tank track if transportation by rail was required.
A Troubled End
More delays occurred when the Allied air force bombed Krupp’s manufacturing plant in Essen. Construction work on the prototype was no longer viable at this location. On 7 December 1944 Krupp reported that the chassis was ready to be loaded onto a flat back railway wagon for transportation from Essen to the Henschel Panzerversuchsstation 96, Haustenbeck near Paderborn. It was recorded as being at this establishment on documents dated 22 December 1944 but missing many of the components needed for the completion of the project including the cooling and fuel system, Gg 24/800/300 tracks and hardened road wheel arms.
The Grille 17/21 prototype was still in an unfinished condition when the German High Command ordered all future work on the program to be stopped. The situation in the 1st quarter of 1945 was such that in their view there would not be any significant advantage in the completion of the project. Resources were limited and they had to be channeled to more important weapon production lines.
In 1945, the US 3rd Army captured the Henschel panzerversuchsstation, Haustenbeck Ordinance proving and tank testing ground in Northern Germany, 50 km south west of Hanover. A selection of German heavy tanks and self-propelled guns were found in working condition. A few prototype vehicles were discovered that never entered production. These included a partially assembled Geschützwagen Tiger für 17 cm Kanone 72 chassis and nearby a 17 cm Kanone 72. They did not find a second chassis or a 21 cm Mörser.
The Allies took the chance to examine this huge weapon system. The three soldiers inside are dwarfed by the sides of the superstructure of the Grille 17/20 SPG. (The Tank Museum Bovington)
The driver sat on the left of the Grille 17/21 at the front. The hull machine gunner sat on his right, (The Tank Museum Bovington)
Here you can see the design of the extended chassis and the rear of the superstructure. Notice that it was an open topped SPG. (The Tank Museum Bovington)
The Jagdtiger SPG was 2.8 m (9 ft 2 in) tall and 10.65 m (34 ft 11 in) long. It gives you a good idea of how large the Grille 17/21 self-propelled gun was when the two vehicles are seen together. (The Tank Museum Bovington)
The front armor of the superstructure was only 30 mm thick. It was not enough to save the crew from a Soviet, British or American armor piercing AP round in 1945. (The Tank Museum Bovington)
The gun chassis rails can be seen on the floor of the fighting compartment in this photo of the Grille 17/20 SPGs fighting compartment. (The Tank Museum Bovington)
large perforated muzzle brake found next to the Grille 17/21 17 cm gun barrel. (The Tank Museum Bovington)
The following photographs are often seen in books and posted on the internet wrongly claiming that they are photographs of a wooden mock-up of the Grille 17/21 fighting compartment. This is a mock-up of the Flakwagen auf Panther NOT the Grille 17/21. The first author to make this understandable error was Spielberger in his book ‘Tiger und seine Abarten’.
This is a photo of a mock-up of the Flakwagen auf Panther NOT the Grille 17/21 (Spielberger)
Wooden mock up of the superstructure of the Flakwagen auf Panther NOT the Grille 17/21 (Spielberger)
Gunners seat mock-up in the Flakwagen auf Panther NOT the Grille 17/21 (Spielberger)
Grille 17/21 specifications
|Dimensions (L,W) Grille 17||13 m (42 ft 8 in), 3.27 m (10 ft 9 in|
|Dimensions (L,W) Grille 21||11 m (36 ft 1 in), 3.59 m (11 ft 8 in)|
|Height (17 & 21)||3.15 m (10 ft 4 in)|
|Total weight||60 tonnes (59 tons)|
|Crew||8 (Commander, driver, 6 gunners)|
|Propulsion||Maybach HL 230 P30 V-12 23 liter water-cooled petrol 690 hp engine|
|Top road speed||45 km/18 km (28 mph/11 mph)|
|Operational range (road)||250 km/125 km (155 miles/78 miles)|
|Main Armament||17 cm K72 L/50 or 21 cm M18/1 L 31 mortar|
|Armor (chassis)||16 – 30mm|
Joachim Engelmann, German Heavy Field Artillery 1934-1945.(Schiffer Publishing Ltd)
Ian V. Hogg, German Artillery of WW2. (Pen & Sword)
Frank V.de Sisto, German Artillery at War 1939-45 vol.1. (Concord Publication Co).
Gordon Rottman, German self-propelled guns. (Concord Publication Co).
Peter Chamberlain, Thomas L.Jentz and Hillary L.Doyle, Encyclopedia of German tanks of WWII, (Arms and Armour Press).
Peter Chamberlain and Hillary L.Doyle, Profile AFV Weapons 55 German Self-Propelled Weapons. (Profile Publications)
The War Office, Handbook of Enemy Ammunition Pamphlet No 15 – 24th May 1945.
SHAEF, Restricted July 1944 – Allied Expeditionary Force – German Guns – Brief notes and range tables for allied gunners. SHAEF/16527/2A/GCT.
SHAEF, Allied Expeditionary Force German Guns – Brief Notes and Range Tables for Allied Gunners – SHAEF/16527/2A/GCT July 1944
Major L.J.McNair, Artillery Firing, (US Army, Fort Leavenworth, Kansas Oct 1919
U.S. Army Council. Handbook of Enemy Ammunition Pamphlet No.15. German Ammunition Markings and Nomenclature.
Panzer Tracts No.10 Artillerie Selbstfahrlafetten by Thomas L.Jentz and Hilary Louis Doyle
Geschützwagen Tiger für 21 cm Mörser 18/1 (Sf.) Grille with the 21 cm Mortar fitted. It is painted in factory fresh Red-Oxide Primer. The length of the gun is noticeably smaller that the 17 cm cannon. The turning dish has not been fitted to the rear of the vehicle.
Geschützwagen Tiger für 17 cm Kanone 72 (Sf.) Grille with the 17 cm gun fitted in fictional ‘what if’ markings. Notice the extended chassis and the large turning dish mounted at the rear.
Both illustrations made by tank encyclopedia’s David Bocquelet