Panzerserra Bunker- Military Scale Models in 1/35 scale: Crusader Mk.III AA Mk.I - 40mm Bofors

Watch out!!

Jabos at 2 o'clock!!

The so-called anti-aircraft point defenses have always been a constant concern of the military, even more so after the advent of dive bombers and fighter-bombers in WWII. The possibility of defending itself from the deadly and precise attacks of the enemy Air Force was sought to exhaustion, and in World War II, the solution to this problem was the use of self-propelled anti-aircraft guns (SPAAG).

Anti-aircraft guns are usually mounted in a quickly-traversing turrets with a high rate of rotation and elevation, for tracking fast-moving aircraft. They are often single, dual or quadruple mounts, allowing a high rate of fire, with its automatic guns. In addition, most anti-aircraft guns can be used in a direct-fire role against surface targets to great effect. Among the weapons developed in that conflict, today we are going to talk about the British Crusader Mk.III AA Mk.I - 40mm Bofors.

Crusader III AA Mk.I 40mm Bofors gun,
Armoured Fighting Vehicle School, Gunnery Wing at Lulworth
Dorset, 25 March 1943 - IWM (H 28356)

History:

In September 1941, it was decided to develop a mount for the Royal Artillery's 40mm Bofors anti-aircraft gun on the then-obsolete and reliable Crusader Mk.III tank chassis. The aim was to meet the British Army's need for mobile air defense to protect its armored formations from enemy ground-attack aircraft.

A Crusader Mk III tank, 1 January 1943 - IWM (E 20823)

It was agreed that crew protection would be limited. The prototype, based on an early Crusader hull (T44381), featured a complex shield whose height was increased with plywood panels. When tested at MEE in March 1943, the turret structure proved too fragile to remain rigid on rough terrain.

Crusader Mk.III AA Mk.I prototype, with early open turret

In July 1943, the Tank Design Department sought to correct the problem in a second tank (T124559) with a modified turret developed by Morris Motors. The number of turret rollers was increased, and attempts were made to reduce the armor height to save weight, but the result was unsatisfactory.

The production model, designated Crusader III AA Mk. I, was built on the Mark III hull. The tank's original turret was replaced with a new, simplified four-sided structure, pyramidal-like turret with an open top and a waterproof canvas cover. A fully enclosed turret version was never produced or put into operational use.

The new, simplified four-sided pyramidal-like turret, with an open top.

The new turret was positioned directly above the original turret ring. Rotation and elevation were controlled by a joystick via a hydraulic system powered by a 250 cc two-cylinder Enfield auxiliary engine.

Crusader Mk.III AA Mk.I production version,
with pyramidal open turret.
Armoured Fighting Vehicle School, Gunnery Wing at Lulworth

Crusader Mk.III AA Mk.I production version,
with pyramidal open turret pointing to rear.
Armoured Fighting Vehicle School, Gunnery Wing at Lulworth

Because it was associated with the Royal Artillery, the gun was not intended to be fired while moving. In addition to the driver, the crew consisted of a gunner/loader and a Commander, who operated the radio No. 19.

Crusader Mk.III AA Mk.I crew

Tests revealed that the turret was not as effective as expected, exhibiting difficulties in tracking low-flying aircraft and an inability to rotate the gun on uneven terrain. Even so, contracts existed for at least 215 units.

Three Crusaders Mk.III AA Mk.I with turrets reversed
and two normal Crusaders in railcars.

The Crusader AA Mk.I had limited production and was soon overshadowed by the Crusader Mk.III AA Mk.II/Mk.III variants (armed with two 20 mm Oerlikon cannons), considered more effective.

A Sherman tank and Crusader Mk.III AA Mk III of the
Staffordshire Yeomanry, 27th Armoured Brigade, during Operation Goodwood
France, 18 July 1944. IWM (B 7522)

The vehicle had its baptism of fire after the D-Day landings in Normandy in 1944. Curiously, many of the Mk.I vehicles sent didn't even use the factory-installed open turret; instead, the standard 40 mm Bofors cannon, with its original ground protection shield, was mounted directly onto the modified chassis.

A Crusader Mk.III AA Mk.I without the large pyramidal turret,
using only the frontal shield on the Bofors 40mm gun (platform facing aft),
heading towards the embarkation area on an English road,
immediately before the Normandy Invasion.
England, June, 1944.

A Crusader Mk.III AA Mk.I without the large pyramidal turret,
using only the frontal shield on the Bofors 40mm gun,
on alert against air attacks, immediately after the landings.
Juno Beach, Normandy, on June 6, 1944.

After the landings, the Allies developed enormous air superiority on the European Front, significantly reducing the threat from the German Luftwaffe. Due to this lack of aerial targets and air threat, the Crusader AA Mk.I had a limited operational history in its intended role, and most of these armored vehicles were withdrawn from frontline service shortly after D-Day.

Instead of attacking aircraft, they were frequently used in a secondary fire support role; the 40 mm Bofors gun, with its high rate of fire and armor-piercing ammunition, proved useful against ground targets such as light and medium tanks, as well as infantry.

Specs:

Crusader Mk.III AA Mk.I - 40mm
Type	SPAAG (self-propelled anti-aircraft gun)
Place of origin	United Kingdom
Service history
In service	1943-1944
Wars	World War II
Production history
Designer	Nuffield
Designed	1943
Manufacturer	Nuffield Mechanizations and Aero Ltd
Produced	1943
No. built	153 - 215(?)
Specifications
Mass	18.8 long tons
Length	5.97 m
Width	2.77 m
Height	2.94 m
Crew	3 (Commander, gunner, driver)

Armour (front-side rear)	Hull: 30x28x28mm Turret: 25x12x12mm
Main armament	Bofors 40mm AA QF 40 mm Mark VI gun 160 rounds
Sec. armament	none
Engine	Nuffield Liberty 27-litre V-12 petrol engine 340 bhp @1,500 rpm
Power/weight	17 hp/tonne
Transmission	Nuffield constant mesh 4-speed-and-reverse
Suspension	Christie helical spring
Ground clearance	0.41 m
Fuel capacity	500 liters in 3 fuel tanks (+136 liters auxiliary)
Operational range	322 km on roads 235 km cross country
Maximum speed	42 km/h (road) 24 km/h (off-road)
Steering system	Wilson epicyclic steerin

The kit:

For this commission project, I will use the old (2008) Italeri kit, which is already well known to our Fraternity, the kit Crusader III AA Mk.I (#6465):

Old, but decent: Crusader III AA Mk.I (#6465) Italeri kit box art

This kit was stored in the darkest depths of my Catacombs, waiting to be brought to life. At the time of its storage, I had purchased a small (big) detail to enhance this model...

And now, a great friend and perfect customer from France commissioned me to bring this girl to the light of the Sun.

Vive la France!!

The English girl who hates planes, in her bag, waiting for her birth...
look at the accessory detail...

A very good metal gun for this project:
RB Models (#35B97)

40mm Bofors metal gun
RB Models (#35B97)

But let's start the work, by the book, of course...

Chassis and suspension

Closing the side armour and upper hull...

And now, we have to talk about the old (and incorrigible...) disappointment of this kit (and all its sisters) in the Italeri brand: the non-existent step on the front fender...

Lad, this is disgusting!!!

The front fenders with this step are just awful!!
Our Majesty is really not satisfied!

It's incredible for a defect to go unfixed for so many years!!

Shame on you, Italeri...

But thank the gods, the Tamiya guys fixed it in 2017!!

Well done...well done, indeed!!

But my girl is of the old breed, so we're going to have to "operate" this creature!! In my previous Crusaders projects, I removed the top portion of the step or used a metal correction...

Old corrections...

This time, I'm going to do a different approach: I'm going to cut the horizontal portion of the step, wear out the vertical fitting for the fender to "go down"... Let's see what happens!!

A new technique for the same surgery, to repair the front portion of the fender.

The awful step has been fixed!!

The comrades raise a toast to that!! Cheers!!

The other side!!

Internal view of the front fenders...

But now, the vertical front section of the fenders doesn't fit...

Two more cuts are needed, with the rivets being removed in the process...

Cutting the steps with the cutter.
Then, I'll use a scalpel and sandpaper for the fine finishing.

Done...

Internal view!! Perfect!!

For the rivets, I cut small segments of Plastruct rod
to the appropriate thickness. All good!!

Left view

More mistakes by Ms. Italeri...

Adding details to the front of the vehicle... Left view.

Right view

Rear view.

The metal cannon is a huge improvement.
Thank you, RB Models!!!

The two 40mm barrels side by side...

With the new 40mm barrel, I have to improve the recoil spring.
The one in the kit, injected in plastic, is simply awful...

The joining of the halves is simply clumsy!!

Beginning the plastic surgery: cut off the portion of the recuperator
to excavate the oblong holes through which the spring can be seen.

Correcting the internal hole of the spring retainer.

Building a new spring with copper wire wrapped around a drill bit.

Testing the diameters and holes obtained. The metal spring can be seen.

Much better!

The new 40mm barrel gun

Testing...testing...

Much better, indeed!!

After upgrading the 40mm Bofors, we're also going to upgrade
the armor plates on the pyramidal turret.
The internal guides are huge and unnecessary (red arrows).
We're going to cut them off!
Notice the injection marks (yellow arrows)

Surgery time!!! The cutter's cuts will be
improved with a scalpel and sandpaper.

Putty in the injection marks

The armored turret plates have been rectified and detailed,
ready to be painted...

Correcting the front hatch, with scribber and plasticard.

Close up view

With the completion of the construction, I made my color and marking guide, using the Italeri markings decals which were correct, but extending the period. I imagined our vehicle being tested beyond March 1943, with the addition of the Lulworth Artillery School insignia on its turret side armor. This detail added a touch of color, without straying from historical accuracy and immediately evokes the traditional British Artillery school. Here's what I imagined:

Panzerserra colors & markings guide

I painted the kit with a mixture of English green and olive drab,
to achieve good color matching.

The turret was painted "open". With the tonal variations applied,
the internal details of the tower can be painted so that it can later be closed.

The turret closed. Note that it must be glued onto a flat surface
to maintain perfect squareness.
Front left view

The turret closed. The turret flor will
be glued in a final step, with the 40mm Bofors.
Rear view

The turret closed.
Right view

The complete turret, with the floor and the 40mm Bofors in position.
Front left view

Front right view

Rear view

After applying the tonal variations to the tower and the vehicle, I applied two very thin coats of gloss varnish so that I could apply the decals without the risk of silvering. Once the decals were dry, I sealed them with another coat of gloss varnish and sealed the entire job with matte varnish, promoting a homogeneous finish.

Decals in position. Starting to paint the original and good vinyl tracks.
I used gun metal paint to do this...
Notice the canvas of the turret under painting, too...

The tracks are glued in place. The look isn't realistic because
they're too tense. I need to add weight to them...

Close up view.

Using shims to compress the tracks against the upper portion
of the wheelsets. A drop of superglue is used to keep the tracks
supported on top of the wheels.

An overview of working with vinyl tracks.
Pure NASA rocket science!!!

Adding the details to the kit. It's not an operational vehicle,
so I'll go easy on the weathering...

Front right view

Rear right view.

Rear left view.

And the girl was ready for working...

With you, the Crusader Mk.III AA Mk. I 40mm Bofors, undergoing operational testing at the Armored Fighting Vehicle School, Gunnery Wing at Lulworth, Dorset, late 1943.