Sisu SA-150 with 23 ItK/61 - dakka on off-road truck

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Put it on a truck
A common dilemma with towed light AA-guns: You need to make them light enough for crew to be able to move them into position without extra machines. Then again too light mounts can’t handle high road speeds and rough crosscountry when towed. This is why you might as well lift the gun on board the truck and that’s exactly what Finnish Defence Force has been doing since 1950s. First this was done with the indigenous 20 ItK/40 VKT, in 1960s with 30 ItK/62 and for many decades with the 23 ItK/61.

Notice the speed limit of 50 km/h painted on bottom of the mount.
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ZU-23-2 to FDF
After WWII the Finnish Defence Forces had quite severe funding issues as the country was paying war reparations to USSR. Long backlog of obsolecent equipment piled up and due to Cold-War relations, Finland had issues purchasing new Western equipment. At the same time FDF couldn’t decide the requirements of their future light anti-air weaponry. Then all of a sudden in late 1960s the Defence Ministry bought about 800 ZU-23-2 guns from Soviet Union. This weapon purchase came as a surprise when Finland made a rather unique trade agreement with the Soviets. They would send different goods and acquire back mostly weaponry, including 130mm artillery, T-55 tanks and MiG-21 fighters.

23 ItK/61 enters service
The anti-air forces weren’t entirely satisfied with the new gun due to the obsolecent lead calculator, but the guns and mount were a great upgrade over their WWII-era weaponry. The 23mm round was twice as powerful as 20mm, the firerate was higher and so was the effective range. In addition the mount was light and quick to deploy in position. There were no notable reliability issues either, despite varying weather conditions. Strangely enough the weapon was named 23 ItK/61, while usually in FDF the latter number indicates the year when the equipment was accepted into service. Perhaps 69 was no good in the concript army.

23 ItK/61
Muzzle velocity 970 m/s
Firerate: 2 x 17 rounds per second
Feed: 2 x 50 round belt boxes
Weight: 950 kg

Photos

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pv kalustokuvat 23 koossa 1000x563 px-02
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23 ItK/95 and continued use of 61
By 1980s the Soviet system was proving worse and worse, mostly due to the sight system similar to those on some 1930s guns. Again there was no money to purchase a new Western system, thus in late 80s a plan was set to upgrade the 23 ItK 61. A thermal sight was added to improve target search and to provide night fighting capability, laser rangefinder to get quick, accurate and constant target distance and the mount was automated. The second operator was removed and his seat replaced with electronics box. This added 200kg to the whole mount, but with these upgrades the effective range was far improved. While the weapon still lacked behind new systems, it was done at far cheaper price and accepted into service in 1995. Also in early 90s 300 more ZU-23-2 guns were bought from East German outlet. While the 95 upgrade was impressive, it was not very common. These days the lighter 61 is still used by more mobile units as their weight and lack of electronics allows faster deployment.

In most firing range photos and videos the full crew isn’t usually present due to strict safety procedures, but in this practical exercise you can see the whole crew of 6. Somehow I don’t think we’ll get the two RK-62 spraying guys in game.

Sisu SA-150 off-road truck
In history ZU-23-2 has been mounted on numerous vehicles and also in Finland it has been seen onboard few different trucks, but most common carrier for it has been the Sisu SA-150. In 1979 FDF ordered a new more powerful truck for towing modern artillery. This new truck, which was directly based on the previous A-45, went through the design and testing process in just 3 years, before massproduction began. From 1982 to 1991 total of 450 were build, which was a lot by Finnish standards of the time. The vehicle was named as Masi, which is an abbreviation from Maasto Sisu = Off-road Sisu. The name was given by the manufacturer to avoid increasingly horrifying nicknames given by the conscripts.

truck-kun

SA-150
Weight: 7600 kg
Load capacity 6500 kg
Length: 6760 mm
Width: 2480 mm
Height: 2900 mm to front cabin (3100 mm to rear cabin structure)
Wheelbase: 3850 mm

Engine model: Valmet 611 CSBA
Engine type: 6-cylinder direct injected turbo diesel
Engine power: 150 kW (204 hp) at 2500 rpm
Torque: 695 Nm at 1500 rpm
Transmission: 6+1 with 2-stage reduction gear
Drivetrain: 4x4

Top speed: 100 km/h
Approach angle: 42°
Departure angle: 39°
Turn circle: 8.2 m
Ground clearance: 0.4 m
Fording depth: 1.0 m

SA-150

Sources:

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Puolustusvoimien moottoriajoneuvot 1960-2000, Markku Mäkipirtti, 2006, ISBN-10 952-5026-50-7

Itsenäisen Suomen Ilmatorjuntatykit 1917-2000, Raimo Vehviläinen, Ahti Lappi, Markku Palokangas, 2005, ISBN 951-91-8449-2

Autocannon, Anthony G. Williams, 17.2.2023, ISBN 1785009206

Finnish Defence Forces
Puolustusvoimien kalustokuvasto - Puolustusvoimat

Brochure from Oy Sisu-Auto Ab printed in 2000

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3 Likes

Only a matter of time!
+1

1 Like

would be a great gap filler for the swedish tech tree

2 Likes

+1 at around 4.3 for the ItK/61 armed variant. The ItK/95 armed variant (if there ever was one) would probably need a higher BR due to the thermal sight and LRF. I’ve also heard that it had a stabilizer but I’ve seen service members dispute that.

The Finnish also put the ItK/61 onto the ZiL-131, which is a tad slower at 80kph.

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There’s also the Sisu SK-181 fitted with the ItK/95, which could work at that higher BR if the Sisu SA-150 armed with the ItK/95 doesn’t exist.

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2 Likes

I added a nice brochure from Oy Sisu-Auto Ab. It has all the tiny numbers about the truck.

There only two things we don’t know about: How the gun is mounted on the truck and how much ammo is caried and where.
pv kalustokuvat 23 koossa 1000x563 px-02

Even if that data isn’t found, it can still be added. Gaijin will probably just plonk it wherever there’s space, similar to the Zerstorer 45, which had no ammo placement data.

3 Likes

That’s probably same with many other AA trucks.

1 Like

i would think it would be around 5.3 the same br as the bosvark (which has the same gun)

2 Likes

Yeah probably. I’m a growing China main so recently whenever I see ZU-23-2 I immediately think ZSD63 (PG87), which is 4.7. Maybe the ZiL-131 version could sit down closer to that BR with its worse mobility.

Well the btr-zd has the guns too and it is 5.7

Also the zsd63 has 25mm guns not zsu-23-2

The zsd63 has 40 round mag with 13 sec reload the zsu-23-2 guns have 50 rounds with 10 sec reload

This is a vehicle Sweden needs since most players aren’t used to SPAA duties with the Bofors guns

2 Likes

All you need for the ammunition capacity is to know how one of the general ammunition crates the ammo was stored in looked and how many rounds it contained. That’s the go-to for many SPAA vehicles which are mostly just a gun(s) mounted on a truck without a standard ammo stowage department or is just unknown.

1 Like

Ooooo yes please! +1 Just please, for the love of snail, please give it more that 150 rounds of ammo🙏

Plopped on the bed of the truck with a crane and duck taped in😂

4 Likes

I hope for those Finnish conscripts to send some photos of the truck.

1 Like

Yeah, a +1 from me! This would be a great AA for Finland.

1 Like

A great gap filler SPAA on an iconic domestic Finnish chassis! The “Masi” is a really fun truck to ride in, especially on offroad trails ;)

1 Like

Masi would now be a fitting addition for 5.0 lineup, specially if one plans to buy KV-1 m1942.

2 Likes