- Yes
- Yes, technically correct is the best type of correct
- No
- No, this is just stupid.
“Wait”, I hear you say, “that’s just a gun!” And you would be almost correct. Almost. It is in fact a gun, but with an engine! This here is in fact a literal self-propelled gun. With a whooping max speed of 7km/h(!), independent steering, and on-board crew driving it, this here is by definition, a self-propelled gun (ie. a vehicle).
Below: The system in self-propelled configuration.
History
With the ever increasing mechanization of infantry, artillery units of the Swedish Armed Forces were starting to have problems keeping up with the infantry with their traditional guns. This problem only increased as time went on and more mechanization of the infantry took place. Though the then current French “Obusier de 155 mm Modèle 50” (Swe: 15,5 cm haubits F) were well liked, their slow deployment was a part of this issue. In addition, the mounts were prone to cracking in the Swedish climate, which further expedited the need for a new gun. Other felt issues were a slow rate of fire and costly maintenance.
So in the 1960s, plans for adoption of a new artillery piece were prepared that would resolve these issues. Criteria for the new gun were formulated officially during testing that took place between 1965-1968. Also, to keep costs low, a non-tracked gun was chosen, similar to conventional guns. The main criteria of the new gun were:
-
Long range.
-
High rate of fire.
-
Great mobility.
-
Off-road capabilities.
-
Better effect per single shell.
In the Late 1960s the FMV (Försvarets Materialverk/Defence Ordnance Material Administration) started working together with Bofors AB to design and produce a suitable gun and ammunition to meet these demands. A few years later, the first guns and ammunition would enter trials and crew training around 1973-74. Sorting out teething issues and setting up production would take a few years, with series production starting in 1978.
Below: FH77 being towed in off-road conditions. With snow chains. It would then be dropped off and drive itself to where it was needed close-by.
The system that emerged was a 155mm gun being able to drive itself with its own engine from the drop-off point to the firing position without any extra vehicles or man-power to set it into place, even in snowy off-road conditions. The engine was also used to power the hydraulic aiming system, allowing the gun to traverse and elevate in all directions automatically via control input, rather than a need for individual gun layers to do that work by hand.
Below: The system deploying itself in the field.
The gun was now using a two-piece ammunition that did away with the classic brass cases and instead used lightweight plastic propellant charge cases, and a crane and loading tray to lift and load the heavy projectiles with.
The tray can hold 3 rounds (only projectiles) ready to fire, with another 3 rounds carried by the crane to be placed on the tray once it is empty. It could be possible to store one more inside the barrel for a 6+1 ammo capacity. The propellant cases are loaded in by hand by placing the case in the rammer ramp and letting it load from there. There is no specific place for these lightweight cases to be placed so they are usually in their 12-round container nearby. For gameplay, I figure you could just ratchet-strap the container to one of the trail legs so they are present.
Below: B-variant deployed. Note the mentioned propellant charge container.
Conclusion
The system would turn out to be quite successful and a NATO ammunition compatible version would follow (FH 77B), also changing the muzzle brake from the original “pepper pot” to a baffle type, which is the easiest way of identifying the variants. It’s main use now is in a modified form on the Archer SPG, as the Haubits 77 AD L/45. There was also some significant exports to India, and some to Nigeria. How that happened is not something we need to discuss…
Specifications (Basic data, see more in the "images from manuals" -section)
Weight: 11,300kg
Crew: 4 - Commander (forward left), Gunner (forward right), Loader/Crane Operator (rear right), Ammo Runners (Carrying ammo to the Loader’s position and propellant cases into the loader).
Below: The 4 crew members in positions during deployment.
With this in mind, you could theoretically place an ammo unit on the left mount leg with 12 rounds, and have the remaining crew hitch a ride on the remaining space on the trails.
Dimensions when deployed
Total Length @ 0°: 10,860 mm
Total Width: 7,180 mm
Total Height @ 0° elevation : 2,750 mm
Total Height @ 50° elevation: 6,750 mm
Dimensions during transport
Driving Wheels Width: 2,200 mm
Support Wheels Width: 2,300 mm
Total Width: 2,640 mm
Total Length: 11,590 mm
Total Height: 2,750 mm
Ground Clearance: 445 mm
Propulsion
Engine:
Pre-Series: Volvo B20A, 59 kW (80 hp) @ 5,000 RPM
Production: Volvo B20B, 74 kW (99.24 hp) @ 5,520 RPM.
Each wheel is powered separately via a hydraulic pump, and is also how the vehicle turns - by powering one wheel over the other.
Max Speed, Self Drive: 8 km/h (pre-series); 7 km/h (production)
Max Speed, Towed (irrelevant for gameplay): 70 km/h
Fuel: Main tank of 40 Liters, 97-Octane gasoline. Two extra 20 liter cans in front of driver’s position.
Armament
Caliber: 155 mm
Rate of Fire (First Stage): 3 rounds in 10 seconds. Self-ejecting.
Elevation: -3°/+50°
Traverse (When deployed):
-With elevation less than 5°: +/- 25°
-With elevation greater than 5°: +/- 30°
Traverse & Elevation Speed: 3°/s
Muzzle Velocity (highest propellant charge): 760 m/s.
Range: ca 21 km
Gunner Sight: 4.0x, 10 degree FoV.
Ammunition (circa values)
Type: 2-piece
Warhead Weight: 43 kg
Propellant Casing Weight: 12 kg (1-4 charges), 16 kg (5-6 charges).
Complete weight for 12-round warhead unit: 600 kg
Complete weight for 12-round propellant unit: 175-200 kg
Ammo Stowage: Special stowage units has been developed carrying 12 warheads and 12 propellant cases - enhetslast (ehl), pg 12 pic. With the crane, three warheads can simultaneously be extracted and loaded onto the gun’s loading table. The warheads can stay on the crane until the three warheads on the loading tray has been expended and then dropped unto it to uphold a high rate of fire with a continuous supply of first stage ammo. On the ammo tray it is automatically loaded into the gun via an autoloader. The autoloader however, requires the propellant case to be dropped into a 1-piece holder, manually by a crew member between every shot.
Gameplay
So how would this play?
One way I would suggest is that you have a “transport mode” wherein you can’t fire and the trails are folded together and you can go at max speed. When you are in position, you can enter “fire mode” and start firing freely. In firing mode you could still have a small amount of mobility to re-position or get towards cover if needed. But it’s very clumsy and slow to do so.
Either way, this suggestion is mainly just for fun. And I’d love to hear what creative ideas you guys might have for a “vehicle” like this. Please leave a comment if you do. And again, this isn’t necessarily a super serious suggestion, so let’s have some fun with it. :)
Sources
-
Försvarets Materialverk, Huvudavdelningen för armémateriel presenterar 15,5 cm haub 77 (A :M 4815/4:2/74)
-
15,5 cm haubits 77 Instruktionsbok. M7786-004750, IBOK 15,5 HAUB 77. Försvarets Materialverk 1981.
https://www.youtube.com/watch?v=Sr_D-8rBxYo
I’m working on trying to get this video public again, as it was quite good. The other two sources above are both primary ones and should suffice regardless.
Wikilink for easy reading: Haubits FH77 - Wikipedia
Images from manuals
FMV Presentation
Spoiler
Instruction Manual
Spoiler
There are more pages and images than these but this image dump covers most of the necessary information. It’s also an exported system so it’s not too hard to find more info online about it. Otherwise just shoot me a message or write a comment below and I’ll try and answer it. :)
Hope you enjoyed.
Sprays, out! o7