Purpose of this blog

Dmitry Yudo aka Overlord, jack of all trades
David Lister aka Listy, Freelancer and Volunteer

Sunday, May 17, 2015

Fat Fox

 Mid week Quiz: I asked you to identify this turret.

In the early 70's the British developed and introduced into service the FV721 Fox armoured car. At the same time they envisioned a command and liaison utility vehicle based upon the Fox hull. This was the FV722 Vixen. Unlike the Fox they didn't quite get her right. Twenty one years ago she was also a vehicle I helped maintain at a museum, and I have some striking memories of her. The reason why I'm writing this is because a few weeks ago I asked, on my facebook page, for ideas on what to write about. One of the responses was for stuff that wasn't a good idea, and I instantly thought of Vixen.
At first glance the Vixen looks a lot like an attempt to copy the Soviet BDRM-2 armoured car, just from the shape of it. However Vixen's roles were very different, despite similar attributes. Vixen was lightly armoured, maximum armour was 60mm, but that was the skid plate on the bottom of the hull. Her glacis plate was 33.5mm thick, but made of lightweight aluminium alloy. The lightweight armour provided protection against shell splinters and small arms. It also allowed her to be air transportable with three Vixen's fitting inside a C-130 Hercules. She was also capable of amphibious use after a screen was erected, which could be done in two minutes. Her Jaguar 4.2l engine could propel her up to 65 mph on land or 3 mph in water. It's likely she'd actually have gone much faster, as Fox's even with the turret have been clocked at higher speeds, and one Fox without a turret has even been said to have reached 100 mph. She was also fully immune to fungus growth and could operate in temperatures from -40 to +50 degrees centigrade.

Role wise she was to be used by all arms of the British Army. The requirements also called for the fitting of artillery observation or engineering stores, such as an assault boat. The main users were seen to be reconnaissance and Royal Armoured Corps units. Vixen had a crew of a driver and a commander, but had space for two passengers. A radio operator sat in the left hand side of the hull, and a passenger, such as an officer or observer on the right. In the RAC units the passenger wouldn't be carried, and this is where the rot started. Due to having no one on the right hand side, there was no one to operate the periscopes, and so the armoured car was utterly blind to the right due to the placement of the commander's periscopes.

Another sticking point seems to have been ergonomics. The study of ergonomics really took off in the post war period with the Cranfield Institute of Technology at Cranfield University. They took a look at a lathe and worked out what the ideal body shape was for its operator where they can comfortably reach all the controls. They termed this human "Cranfield Man". Cranfield man was 1.35m tall, with shoulder width of 0.61m and arm span of 2.44m...

Well Vixen was assessed for the ergonomics of the vehicle. This included such things as checking to see how much support the seats gave to a soldier's posterior. One thing they noticed was that when the commander rotated his turret he'd be kicking the driver in the shoulder blades constantly. Equally there was an utter lack of headroom, and the report highlighted that as an issue unless a size limit was to be placed on its users.

However that was not the biggest issue with the crew positions. As I said I sat in one of these twenty one years ago, and the position has left a lasting memory; the passenger seats face directly forward. The leg wells are angled 45 degrees towards the centre of the vehicle, whilst your work station, such as the radio's or maps are 45 degrees to the other side. Try positioning yourself in that position now, and you'll see how utterly uncomfortable it is. These positions were not adjustable and locked in armour plate. The idea of driving cross country in such a position is horrific, because even sitting still inside a maintenance bay it was incredibly uncomfortable.

Quiz answer:
I dropped a clanger here. Here's another picture of it:
When I first glanced at the turret (from the other side of the car park) I saw the overhang at the rear of the turret and thought KV-1. When I got closer I thought M3 Lee. However I failed to spot something. An M3 Lee turret doesn't have a loaders hatch. So I'm pretty sure its the turret from a Staghound armoured car.

Image credits:
Cranfield man

Sunday, May 10, 2015

Some old Junk

Those of you who follow my Facebook page will have seen that this week I didn't do my usual mid week post, with added madness. This was because I was away. That's the bad news, the good news is I was at Bovington tank museum sifting through their archives. But before that I had a stroll around outside, and there's quite a few interesting tanks out there which most people don't see, as they park up in the car park then go into the museum. So I had a stroll about and took some photographs.

One of the first tanks you'll see is this T-55 (or is it a T54?) tank. Note the odd contraption over the gun barrel.

Next tank you pass is a range target rescued from one of the UK's gunnery ranges.
As you can see its a very battered Matilda Infantry tank. The impact just above the gun trunnion has cracked the turret casting. You can also get a good impression of how heavily armoured this tank was.
 The next photograph isn't a tank, its the kerb stones along side the road. Bovington Camp is still an active military base, and is used for training. Both days I was there we had Challenger 1 Driver Training tanks moving about. When one of the drivers gets a bit too close to the kerb the tanks tracks smash down on the stones and chop them up.
Outside in a pretty bad way is this Churchill Gun carrier.
Interestingly she's still got her main gun, as most of the conversions had the gun removed and were used to carry Snake mine clearing charges. Which, apart from 25 or so on the books of the Calgary tank regiment at the time of Dieppe (although not scheduled to land) was the closest these machines came to combat.

Next to the Gun carrier you have a wrecked Cromwell chassis, intrestingly on this tank the turret has been split into two.
That's the front of the turret on the left, and the turret is almost upside down.

Next we have the Action X turret.

And then, behind it a mystery turret.
But what is it? Its got parts of it which suggest Chieftain, but other parts that scream Action X/FV4202. Its been suggested its some form of prototype Chieftain turret, which would make sense.

By this time the Archives had opened and I had documents to read. While going through I did find one thing that made me laugh. Luckily Mr Wheeler the head librarian was there and he gave me permission to show this to you. There's a hand written note suggesting its from 1912-1914, although those dates are suspect to my mind. Its the submission for a wheel-cum-track, amphibious armoured vehicle, with what appear to be two guns.

I don't even want to think of how complicated and impossibly hard to maintain and build that would have been.

If you want to support Bovington and help it continue its good work, then you can of course join the Friends of the Tank Museum.

Sunday, May 3, 2015

Who Rules the Waves?

This week I asked How much did Nicholas Straussler get paid for inventing the DD tank. Answer after the article.

As you may be aware the World of  Warships has finally released the Royal Navy into the game in the form of HMS Warspite. Upon hearing the news of the arrival of the largest, most important and powerful navy in the world during the scope of the game I figured I'd share some test data I found at an archive.
HMS Warspite
HMS Warspite's first taste of action was on the 31st of May 1916. When probing through the murky afternoon in the North Sea with several other British ships she ran into a German fleet. This was of course the battle of Jutland. Early on in the battle she appeared to be heading on a collision course for HMS Malaya.  Her captain ordered her 20 degrees to port, but about this time she took a hit to the steering gear, which jammed it in the port position.
This turn narrowly caused her to miss ramming into HMS Valiant, passing close to her stern. The crew were wrestling with her trying to get her under control, and this left them heading towards the enemy fleet, and slowing at the same time. Seeing the threat HMS Warspite's captain ordered full speed. This meant that she sailed in a giant circle and at the closest point to the enemy fleet she was just 12000 yards (about 10Km) away from the German line. Then as she extended away, the crew were unable to regain control, and she made another circuit past the German line. During these circles she took a massive battering, with about 150 hits, although she survived. After the second circuit she managed to withdraw.
During the Second World War HMS Warspite returned to the North Sea, and during operations there a Swordfish plane launched from her bombed a U-boat, which was the first sinking of a U-boat by a aeroplane.
Wreck of HMS Warspite, when she broke free while being towed to the breakers yard after the war

 If you'd like to know more about HMS Warspite, both in World of Warships and in history, see The Mighty Jingles Youtube video here.

In the North Sea there lay another giant battleship, the German Tirpitz. She was larger than HMS Warspite, faster and had a larger crew compliment. She was also much more modern. But in respects to the armour and the guns she was roughly the same.
Tirpitz however didn't have anywhere near the list of battle honours that HMS Warspite had managed to achieve. She spent most of her war protected in a fjord being attacked by the RAF. To counter the aircraft smoke pots were emplaced that could lay a blanket of obscuring smoke over the area. These managed to shroud her several times as the super accurate 617 Squadron tried to attack her with Tallboy bombs. Each time the smoke foiled them, and the bomb aimers were ordered not to waste the valuable Tallboys by area bombing due to their cost and the slow speed of production. However on one occasion, one of the eagle eyed bomb aimers managed to plant one into her deck towards the front of the ship. Another near miss damaged her steering gear.
Later she was moved to Tromsø, and again 617 Squadron attacked. This time the Germans hadn't had time to install the smoke pots, and the battleship lay naked beneath the RAF's bombers. The resulting damage caused a massive explosion and the ship to capsize.
Tirpitz being salvaged
The above is nothing new to those of you who know your naval history. However here's the interesting bits. Immediately after the war armour plate was salvaged from the the Tirpitz's hulk. It was compared to British standard plate in firing trials. The guns used were 15" weapons firing APC MK XVIII shells. The plate was angled to 30 degrees. Although both types of plate were of cemented armour manufacture, and about the same metallurgical quality the British plate was found to be superior by a significant margin. This is likely due to the depth of hardness facing, the British depth being nearly twice that of the Germans (6 inches against 3.5 inches). This amounted to needing a difference of about 50 feet per second to achieve the same results. The trials were repeated against thicker plate armour recovered from the Meppen proving ground, although the difference in that plate amounted to 100fps. This confirmed the results.
Note: the Tirpitz plates were only used for a single impact trial, while the British plate was used for multiple shots.
Tirpitz plate after getting hit by a 15" shell
So if the two mighty ships had met would the British would have walked away unscathed? Maybe, the German guns were of a more modern design and had a higher muzzle velocity, well within the margin needed to achieve the same results. However the closer range may have meant the rounds would bounce. Either way this is only the belt armour. The rest of the ships armour, excluding the gun turrets was much thinner.

Results of the tests

Answer to the Question:
Nicholas Straussler's company was paid £2,792 0s 0d. The vast majority of that was wages. In todays money that's about £598,500. Not a bad investment considering that for that the Government got a Fully converted DD Tetrarch light tank.
Image credits:
www.helstonhistory.co.uk, www.maritimequest.com, www.jamesgdorrian.com and www.historyofwar.org

Sunday, April 26, 2015

Schwimmpanzer 36

In the middle of the week I once again put a quiz up on my Facebook page. The question was "What is this?" As several of you guessed its body armour, but for what animal? Answer after the article.
On 26th of February, 1936 a report was filed by the British intelligence agencies about some alarming information coming out of Germany. It was the development of amphibious tanks. The report caught the British a bit by surprise as at the time the only tank type the Germans were known to own was the Panzer I.

The report describes several incidents of amphibious tanks collected from sources throughout Austria and Germany. In the first report in 1932 an Austrian source said that the Germans had built a very good amphibious tank, and that two versions of it were in store at Kummersdorf. During the next two years continued reports came out about an amphibious tank designed by the German equivalent of the British War Office. These reports named the firms involved, Krupp, M.A.N., Bussing and Magirus. However all mention of the vehicle suddenly stopped and it seemed to drop off the radar.
Maybe the mystery tank was an early Tauchpanzer?
Then in 1935 a report arrived of the German navy carrying out tests at Kiel of an amphibious tank that travelled 1.5 miles to shore from its launching point. This report gave the vehicle statistics; it was described as 6.5 ton in weight, with 22mm of armour and propelled by a 75 hp engine, giving it a top speed of 28 mph. Dimensions were listed as 20.5 feet in length. A 47mm gun and machine gun were mounted in a turret, and it had a crew of 5 men.
Both the screw and rudder are under armour, and tank can switch to water mode in about 5 minutes, without the crew needing to leave the vehicle. It was also described as a wheel-cum-track machine.

Upon reading the performance of the vehicle the British were intrigued, and a bit worried! At the time the standard British tank was the Vickers Medium MKII, although the Medium MKIII had been prototyped. This strange Panzer had better armour, the same fire-power, was faster and amphibious. All in a smaller package.
However not all everyone was convinced with one technical expert saying:

"It is surprising that these tanks are also wheel-cum-track machines as this adds extra complication and weight in addition to the screw and rudder.
The length of 20 feet, 6 inches is greater than one would expect of a 6 ton tank and the 22mm of armour could only be in a few places around the turret.
If the data given is correct then the tanks must be a wonderful achievement in design.
Frankly we do not believe that this information is correct in every detail.
Perhaps a Panzerspähwagen Schildkröte?
Pretty scary stuff for a nation surrounded by water. However with modern research we can actually make a good guess as to what this tank actually is. It also highlights, I would hope, the difference between reality and the strange world intelligence departments live in.

First the tank is in fact an armoured car, hence the confusion about the wheel-cum-track. Even then the number of road wheels was wrong with 10 being reported, but the vehicle having only eight.
The mysterious vehicle was, I think,  the very German named "Mannschaftstransportwagen I", from now on referred to by its initials "MTW".

Several of the factors in the reports tie up nicely with the historical record. The vehicle was first designed in the very late 1920's. It had a five man crew, a turret with a 37mm gun, and the screw was under armour. One of the reports says it was powered by a 100 hp engine, which is the same power the engine on the MTW had.
Equally the list of firms while not a perfect match, do have some similarities. Especially the involvement of Magirus. The armour however is wrong with the MTW having 13.5mm all the way round. That is however, still better than British tanks of the period. Also remember the source that is supplying this information wouldn't have had time to measure or take notes, instead they would have had to measure by eyeball and then remember. Anyone who has dealt with getting eye witness reports will tell you how fun that can be.
Plans for the MTW's turret.
For me the final proof is the fact the MTW seemed to disappear for a while. According to various sources it was in Russia being put through its tests, then returned to Germany for more tests, where it was spotted and at least semi-correct details were passed on to the British.

militarymodels.co.nz, www.wehrmacht-history.com and MadestCat from the EU server

Special tanks to MadestCat, for providing details and photographs.

Quiz answer:
Earlier I asked What is this body armour for? The answer is, a Sheep. You might of course be wondering why anyone would design and make body armour for a Sheep.
In 1956 the Admiralty were investigating how to protect personnel from underwater explosions. The idea of a Rubazote suit and abdominal guard was floated, and was trailed by building a suit for a sheep and placing it in the water with an explosive charge. The system failed to work.

Sunday, April 19, 2015

The Best Laid Plans

A few weeks ago I covered an action of C Coy, 6th Battalion, Royal Tank Regiment in 1936 when deployed to Palestine for the Arab Revolt. Well the file that came had several other reports, so here's more accounts from those actions.

During the start of June the Jewish settlement of Ben Sherman had been repeatedly attacked by snipers. The Arabs normally used a wooded hill to the north of Ben Sherman, and then fired upon the town. The attackers were presumed to be from the settlement of Lydda.
To prevent these attacks a plan was drawn up. A subsection of two MKIII Light Tanks would take up position to the west of the colony. Upon an attack being launched they would move up to a Wadi short of the wood and open fire. This would force the attackers either to head south into the colony, where a force of infantry would be stationed, or to try to flee over open ground to the south east, which was covered by another two tanks.
The tricky part of the plan was getting four tanks into position unobserved and camouflaging them. Both sub-sections made wide detours to reach the area, hoping the Arabs very good intelligence network wouldn't warn the locals. One subsection made a normal road march then as darkness fell turned off the road in the middle of nowhere.
After 2.5 km it reached a Wadi which then took half an hour to find a crossing point to use, it also successfully navigated irrigated fields, and cactus hedges up to 12 feet high. They even encountered one electrified fence. This subsection was in position only ten minutes late, had covered 6 km in just over an hour though very dense and difficult terrain. However both subsections of tanks were in position and camouflaged very well, as you will see.
On the 12th of June three Arab snipers were spotted crawling through the maize field, the same one in which one of the subsections was camouflaged! They were coming from the village of Beit Nabala to the west, not Lydda to the north. This of course caused some issues with the British plan, as the route of advance for the Arabs was directly over the British position. The three Arabs carried on crawling closer and closer. Eventually they reached a point about 30 yards away, luckily this was the closest their course took them. This scout party was allowed to pass to ensure the British caught the main body of attackers.

 Shortly afterwards the main body of attackers was seen advancing on Ben Sherman. At the sight of the main body one of the NCO's in the subsection used his radio to warn the other tanks. However the noise of the radio and the NCO's voice gave the position away, the Arabs were that close and the tanks that well camouflaged. Immediately the Arabs took the tanks under fire, who quickly replied with their machine guns. The Arabs fired 21 rounds and the tanks 117. After this brief fire fight the Arabs dispersed and were never caught.

The original map submitted by the commanding officer in his report to describe the action
On 15th of July a section of three light tanks was escorting a patrol of infantry in the same area when it came under attack. This patrol had a 3" Stokes Mortar with it which opened fire immediately, however, this was before the enemy positions had been located, and caused the Arabs to immediately disengage. They were pursued by the tanks and although the Arabs positions were overrun, no enemy casualties were caused as the area is criss-crossed with old Roman ruins and caves, giving the Arabs plenty of cover to break contact,. So despite fleeting glimpses of Arabs none were caught. During the patrols around the area one of the tank commanders was badly injured, when his foot became stuck between a turret control pedal and the wall of the turret. As this happened the gun caught on a tree as the tank drove past. The tree forced the turret to rotate wrenching the leg of the commander. This left the man in hospital for two months.

Image credits:
http://www.aviarmor.net and http://www.oocities.org

Sunday, April 12, 2015

Tigers for Breakfast

The following article is put together from multiple sources, each one not quite tying up with the others. So some of the elements may later turn out to be out of sequence.

By January 1943 the war had turned against Germany. At this point the allies were pushing the Germans from two sides in North Africa, including in Tunisia. On the 31st two companies of infantry and two troops of six pounder guns were dug in covering the road leading to Robaa. They were on an area of rocky rough terrain on the side of the hill, with the German lines somewhere to their front. At about 0600, in the pitch darkness reports start to filter back from the infantry that they can hear tank movement to the front. Immediately the two troop commanders of the AT guns leapt out of the truck they'd been sleeping in and struggled up the hill. The Lieutenant for the 2nd Troop in his haste just threw on a greatcoat over his pyjamas before dashing to his troop. Lt Stanley Edwards of 1st Troop however had only to pull on his boots.

About an hour later just as the sun was peeking over the horizon, the huge bulk of a Tiger peeked over the crest of the hill. The Tiger was still new to Tunisia and the British had hardly fought them. The giant hulking monster clanked forwards, then suddenly halted. It had spotted a string of explosives the infantry had placed across the road. Lt Edwards had wanted to wait until the German tanks were much closer, so he ordered his guns to hold fire. The Tiger then began to open fire, shelling British positions, but still Lt Edwards didn't give the order to fire, hoping the Tiger would move closer. After about ten minutes he knew the Tiger wasn't going to oblige them, so he released his guns. At a range of 680 yards, Sergeant Marcus Bauer's 6 pounder was the first to fire. His round hit the side of the tank at such an extreme angle it ricocheted off. Along with the storm of 6 pounder shells the Tigers were hit with a hail of small arms, which forced the tanks to button up.
The Tiger then lurched forwards. The next four rounds did nothing more than gouge chunks out of the armour. However as the Tiger was moving the crew had much reduced visibility due to being buttoned up and they didn’t know where Sgt Bauer's gun was situated. So the tank had slowly been turning away from the gun. The next volley of rounds at a range of 650 yards all went through, and with three penetrating hits the tank lurched to a halt. Two other armoured vehicles accompanying the Tiger had been set on fire by the anti-tank ambush.

Now the Germans replied, another Tiger, and several other Panzers (Presumably Panzer III Ausf N) sat hull down on the ridge line and began to hammer the British positions. This storm of fire caused several casualties, not least of all Sgt Bauer's gun layer. Sgt Bauer immediately leapt into the layers seat, where he would remain fighting the gun for the rest of the day.
The Germans now made another attempt, a third Tiger and two Panzer III's roared over the ridge, and rushed towards the British line. Lt Edwards had ordered his guns to hold their fire again. This time the Germans played along and roared down the road, past the knocked out first Tiger, they punched through the infantry screen and headed towards the rear. Sgt Bauer's gun was almost overrun by this aggressive attack. However the 2nd troop of six pounders came into action, hammering the Tiger. Sgt Bauer also opened fire and between them quickly set the Panzer III's and the Tiger on fire. The Tiger brewed up on the first hit.

Now Lt Edwards ordered Sgt Bauer to try to set the first Tiger on fire. As he started attacking the first Tiger, the Tiger on the ridge line fired towards his position every time he fired. Every round Bauer fired had hit with no sign of starting a fire. With the return fire from the Tiger on the ridge getting closer it was decided to save the gun and cease trying to ignite the enemy tank.

During the rest of the day the Germans poured fire on the British positions including artillery and a very nasty air strike. That night the Germans launched a second attack, their dismounted infantry closed within range of the British line and began to lob grenades at the infantry. After a day of fighting the British were in no mood for a close action fight and with their morale gone they began to flee. This left the two troops of anti-tank guns as the only defenders holding the line. The Germans quickly recovered and towed the first knocked out Tiger away, then began to press forward.
Sgt Bauer stayed at his gun and fought with the rest of his platoon. At one point the Germans were a mere 15 yards away from the gun. At this point when all seemed lost reinforcements in the shape of fresh infantry arrived. With no hope to tow the burnt out Tiger away the Germans quickly set some large demolition charges and blew the Tiger to pieces before falling back.
This drawing was taken from a German assessment of the Tiger recovered from that battlefield. Black dots show penetrations.
This was the first time a Tiger had been knocked out by enemy action and destroyed. For their actions on that day Lt Edwards was awarded a Military Cross, and Sgt Bauer a Distinguished Conduct Medal.

Image credits:

Sunday, April 5, 2015

Pitfalls of tank Design

Earlier in the week on April 1st I asked the following question on my Facebook page:

"There's a large debate on which is the better rifle, the Mauser or the Lee Enfield. Well True or False:
The record for shots per minute from a bolt action rifle is 38 rounds into the bulls eye of a 12" target at 300 yards."

The answer will be at the bottom of this page, so feel free to contemplate the question, and see if I was pulling a double bluff due to it being Aprils Fools Day. Anyway onto the main article:

When designing a new armoured fighting vehicle there's many factors to worry about, transmission protection and cost to name but a few. But even a well designed vehicle can fall foul of the oddest issues. Just after World War Two the British designed and built a new generation of Carriers to replace the ageing but awesome Universal Carrier. This was called the Oxford Carrier.

Oxford Carrier
A newer and better version of the Carrier was being tested, known as the Cambridge Carrier. However it was at this point the concept of Carriers fell out of favour and it was decided to move on with a proper APC. Its interesting to note that there was a lot of interest in the Canadian Iron Crown project that produced the Bobcat IFV, and the British nearly skipped the plain APC. However it wasn't to be and the FV432 was born.

From the first it was named the Trojan. However after some press an issue cropped up. In December 1962 a letter landed in the mail bag of the War Office from a solicitors office. The solicitors demanded that all reference to the FV432 Trojan be dropped by the War Office as the use of the name would be injurious to their clients, one Trojan Limited.

I'm sure you can see how you might confuse this 1963 Trojan car with the FV432 APC.
Now I know what you're thinking, would this be Trojan, as in the makers of certain well known rubber contraceptives? No, it was actually a motor vehicle manufacturing firm in Croydon, Surrey.
This of course led the War Office to search for alternative names. The first name they came up with was "Thruster" (no, I'm not making this up). Although other names suggested were "Tomahwak", "Tuscan" and "Troy". All these were checked over by the governments lawyers and found to be usable.
By the end of January the solicitors had issued a full list of demands, namely that the War Office stop using the name Trojan, that they prevent the name being used by any contractors and the government issue a statement in the national and technical press.
On the 11th of March 1963 another letter arrived were the solicitors demanded a statement to the House of Commons on the subject and apparently included a statement that was to be used in the press release. The War Office released a slightly modified version of the statement in The Times on 25th of March, but told the solicitors to go away about the statement to the House of Commons.
On 9th of April the name Trojan was officially deleted from records.
However it didn't quite work, unofficially the FV432 was still very rarely called the Trojan by soldiers, this was still happening even in the late 1990's.
In a way it was a lucky escape for the FV432. As the latest version, the MKIII now uses ribbed armour, you can only imagine the jokes that would follow!
FV432 with added protection.

Right now back to the True or False.
Hands up those of you that found out about Sgt Instructor Snoxall putting 38 rounds into the bullseye at 300 yards within a minute in 1914?

Well there is some doubt about if Sgt Snoxall even existed. Ian Hogg makes mention of him in a book on small arms, and it seems that is the source of the quote you see everywhere. But other details are missing. Other people have looked, but been unable to find anything more on his existence. There may be a book from 1922 that makes the same claim as Ian Hogg does.
What is well documented is that Sgt. Maj. Wallingford managed to achieve 37 rounds on target in a minute.

Image credits:
www.canadiansoldiers.com, www.defense-update.com

Sunday, March 29, 2015

The Cambridge Camal

Last week we looked at amateur hour when it comes to inventing anti-tank weapons. This time around lets look at what craziness the scientists can come up with.

In this particular case the shell came first and then it was realised that the principles behind the round could solve an Ordnance Board requirement for a new infantry support gun of extremely light weight.

The shell in question is called a Cambridge Projectile. It was developed sometime in 1943. The idea behind it was for a flame weapon with much longer range than a normal flamethrower. To achieve this it needed to have a high capacity, and of course the highest capacity you can get is a cylinder, so that's exactly what it was, a plain cylinder filled with flammable liquid. If you rotate a cylinder of liquid, like you would a normal shell, it will become very unstable due to centrifugal forces. So it was decided to fire it from a smoothbore weapon. Of course a blunt nosed shell fired from a smoothbore will also be horribly unstable in flight and thus very inaccurate. However it was discovered (possibly by someone at Cambridge, hence the name?) that the if sheath of unstable air was brought behind the centre of gravity the shell would then become very stable.
During development they were aiming for accuracy at extremely long ranges, it was at this point the obvious occurred, if you can achieve a satisfactory degree of accuracy at long range at much closer ranges the accuracy would be extremely good.
This combined with the Cambridge shell's high capacity meant that it had a number of envisioned uses such as Flame, Incendiary, Smoke, Chemical Warfare, Hollow Charge and Low Shrapnel HE. The difference in capacity can be seen from this table:

So with a clear advantage and having overcome the main disadvantage normally associated with a blunt nosed shell the rounds moved onto the testing stage.
It was found that the shells would often deform at the base when firing due to the pressures. So the same ballistic witchcraft that created the sheath of turbulence was applied to the issue of the shell, and the scientists overcame the issues. (To be honest at this point I lost track of what the document was talking about as I'm no ballistics expert!)
Rounds for the 3" mortar were developed and tested. But despite the advantage in payload the amount of material was still insufficient for a suitable flame shell.
In July 1943 trials were carried out with a round for a 3" howitzer, of the same type mounted on the Churchill I and the Matilda CS tanks. Its interesting to note that both these and the later 75mm guns are rifled, yet the very principle of the round needs it to be fired unrotated. However the document I saw doesn't mention how this was dealt with.
As the 3" was obsolete by this stage 22 rounds were manufactured for the Royal Ordnance 75mm. In comparative trials against rotated 75mm shells in May 1944 the Cambridge shell was considerably more accurate up to 2500 yards, despite being lighter and having a higher payload.
The test gun
To carry out the first trials a simple smoothbore gun was constructed. The original shell was made of impregnated Bakelite paper filled with thickened petrol and WP. The simple nature of the weapon can be grasped by the fact that the Cambridge shell didn't have a cartridge case, and so the gun couldn't be depressed lest the round fall out. Although production shells did have a cartridge case.
Recoil from this gun was managed by it having a very heavy steel barrel of around 200 pounds, and a pair of small springs to deal with the remainder of the recoil.
Test round strike on a tank
It was at this point the Ordnance Board requirement appears. They needed a lightweight gun that could be towed or manpacked, by a minimum of two soldiers, with no single load exceeding 100 lbs, and a gun crew of at most four. This of course meant the maximum weight of the complete weapon could only be 200 lbs.
Its role was to defeat any enemy tank it would meet and defend infantry. The reason for its lightness was so that it could keep up with the infantry in terrain that would prevent normal AT guns being brought up, such as if the infantry crossed an anti-tank obstacle or penetrated a mine field. Minimum range was to be 500 yards, and at that range the weapon must be able to hit a stationary five foot square target, or a moving five foot high by 15 foot long target doing 10mph. Rate of fire was to be at least five aimed rounds per minute.

The gun built to test fire the Cambridge shell was used as a starting point. The gun was called the "Camal gun" (Or in one entry in the documents the "Cam-Al gun"). This is presumably due to the abbreviation of "Cambridge" which is "Cam", and the light weight portability that resembles Camel guns from the previous centuries.
The heavy steel barrel was replaced by one made of RR77 Aluminium alloy. This has a weight one third that of steel. In fact the majority of the gun was made out of this alloy. This brought the barrel down to a weight of 47 lbs.
The recoil was managed by adding an oil type recuperator slightly modified and taken off a Vickers S gun, and the breech was an interrupted screw type. Even so the recoil was too great to allow it to be fired on a tripod giving 360 degree arc of fire, so they had to settle for the minimum in the requirement which was 90 degrees.
The final version of the mount had a tripod with two long rear legs and a shorter front leg. However the requirement also called for it to be towable. So the gun was designed that the front leg could be removed and replaced with a simple axle and two light car wheels, while the longer rear legs became the towing bar. Once it arrived the axle and wheels could be simply unlatched and the normal leg fitted.
The final design
The final point was destruction of the enemy tanks. Unrotated shells are very good at firing HEAT so it was obvious this would be selected. A Royal Ordnance 95mm HEAT cone was cut down to fit the dimensions of the 3" Cambridge shell and the round tested. In the first test the 3" shell went clean through 120mm of armour at 30 degrees. A second later test achieved penetration of 150 mm plate at 30 degrees. To give you an idea this sort of performance would likely go through the frontal armour of a Panther, and might cause spalling inside a King Tiger. In comparison the 95mm round would only get 93% penetration of 110mm plate at 30 degrees.
Muzzle velocity of the shell was recorded as 710 feet per second, and with 5 degrees of elevation on the gun barrel the round travelled 818 yards. In addition a HE and WP shell were developed for the gun.

The document I saw doesn't go into the fate of the Camal gun. But I suspect it's likely that as the war was winding up and advances in other man portable AT weapons caused its demise.

Sunday, March 22, 2015

Don't Panic!

Due to real life workload and time issues, the articles for the next few weeks will be a bit shorter than normal. On the plus side it means I can use some of the funnier or more interesting pieces I've had that I've not been able to make a full article out of.

In July 1942 a note was received by the Prime Ministers office. It stated that the British military mission to the US was sending home samples of a new "anti-tank rifle which shoots a rocket propelled projectile". We of course know this weapon as the famous Bazooka. Prime Minister Churchill of course wanted to see it in action. The demonstration was held at Shoeburyness on the 15th of August on a US T1 rocket grenade launcher. The results were less than impressive. It should be noted that these weren't full trials, but just a demonstration. However the back-blast was judged to be too dangerous for prone firing, and "there is a constant danger of prematures." The weapon was also judged to be too flimsy for field use.
Equally they were unable to view the armour penetration as the weapon missed the target all day.
The Bazooka's one selling point, its recoilless nature wasn't new to the British. A recoilless weapon had been created by two Home Guard officers, one of whom was called Jones, the other was named Wise. They created the Jones-Wise Projector. Its once again proof that smart people are often only smart in one way. Between them they designed a weapon that used a very clever system of achieving recoilessness, a system that is used in part in a lot of modern weapons.

These two officers were serving in the Hampshire Home Guard, seeing as I can only find one mention of the Jones-Wise projector, and its from 32nd Hants Battalion, Home Guard, one would presume that is the unit the two officers served in. It was first brought to the Prime Minister's attention in October 1940.
The Royal Navy trialled the weapon, as did the Army. However they both turned it down. The Royal Navy because they deferred in the matters of anti-tank weapons to the Army. The Army turned it down because the Home Guard had Northover projectors, the devastating Blacker Bombards and the Smith Gun was just coming into service. It was felt another AT weapon was surplus to requirements. Plus its rather unique design possibly raised some eyebrows.
No, a different Jones!
The weapon was described by one officer that saw it as a "Heath Robinson contraption", and although I've yet to find a picture of the device there is an ample description.
It was a semi-circular trough with a parallel sighting bar, shaped a bit like a rifle, with sights on top. One would also presume it had some form of tripod mount. Into the trough a steel tube was loaded which contained a complete round. Upon firing the round was fired outwards, and the barrel backwards, which made the weapon ready to take another shot instantly with no recoil. This system is very similar to one used by many anti-tank guided missiles today, such as the Milan.

The issue of course is that the steel tube weighed 34 Lbs, and was flying backwards at a high rate of speed, would be incredibly dangerous to friendly soldiers. Plus the entire weight is the guns barrel, and each round would need a corresponding barrel. So while the actual gun was cheap to produce the ammunition would be expensive.
Finally one needs to make mention of the firing system. The firing hammer strikes a cartridge sticking out of a touch hole on the steel tube. Why is that odd I hear you ask, well because its a hammer. Yes, one of the crew members had to whack the cartridge with a normal hand held hammer to fire the projectile, presumably this would make fine aiming and shots against a moving target interesting to say the least.

Sunday, March 15, 2015

Tiger gets the Bird

Despite what many say the British anti-tank guns of World War Two were always a match for their targets. This happened simply because the British tended to look forwards. Just as the two pounder was coming into service design work started on the six pounder. Equally as the six pounder was just entering production design work started on its replacement. The replacement was to be the famous 17 pounder which was required to penetrate 120mm-150mm of armour.  This 3 inch gun hurled its shot at over 800 m/s. This performance was achieved with the shell technology of the time such as normal armour piercing rounds. Later developments such as ballistic caps and even APDS (armour piercing discarding sabot) meant the gun stayed a devastating AT gun throughout the war.
Although the gun was ready in early 1942 the design of the chassis lagged behind, leaving the gun with nowhere to go. Luckily the six pounder was more than capable of dealing with the German armour then in the field.
Then the War Office received worrying news. Ultra intercepts had determined that a new German heavy tank was being deployed to the African front, this was of course the famous Tiger. While the 6 pounder could deal with the Tiger, it required skill, nerves and a spot of luck. So the War Office issued an urgent requirement for the 17 pounder to be deployed. The solution was to mount the 17 pounder gun on a 25 pounder chassis. Although the 25 pounder carriage was used to firing a much lower velocity round the study construction stood up to the punishment inflicted on it by the forces of the 17 pounder. When fired it was described as " [...] something of a lively weapon.”
One curiosity is the 25 pounders turntable. Some sources say it wasn't used, while others indicate it was. As most of the pictures show the turntable in place it is likely that it was used.
To prevent German intelligence getting wind of the surprise in store for their shiny new tank the 17/25 pounder, as it was officially known, was codenamed "Pheasant". In October 1942 59 guns were shipped to Tunisia, with a total order of 150 pieces completed by December that year.
In early 1943 The Afrika Korps was planning a spoiling attack against the 8th Army. But again the British had been warned the attack was coming. So they prepared to hold in the area of Medenine. More and more preparations were made, and by the start of March Stephen Wier, one of the officers involved in the defence, said 'I have so many anti-tank guns I am having difficulty in siting them."
This array of fire-power included everything from 2 pdr's all the way up to and including 3.7" AA guns. It also included the Pheasants.
The defensive line was covered by fake minefields. These were placed so as not to restrict any counter attack by British tanks. But by clever positioning they were placed to force the German panzers to expose their flank to the Allied gunners. The troops were issued with orders not to engage until the AT guns had opened fire.
Due to still being secret weapons the Pheasants were sited to the rear, with orders not to fire unless the front line was breached.

On the morning of the 6th of March thick fog covered the battlefield. When it lifted the area to the front was covered by the German army as it advanced. In accordance with their orders the defenders held their fire. The Germans spotted the false minefields as they advanced. Even with tempting targets such as exposed tank commanders the troops held their fire. The German tanks followed the line of the false minefield and as planned they exposed their flank. The anti-tank gunners let fly instantly knocking out the first 4 tanks. Another tank had its tracks blown off by a salvo of mortar bombs. The rest of the day long battle was the Germans trying to advance into the face of overwhelming fire-power.
During the next week the 17 pdr's came into action as they were used to snipe from forward positions against the Germans. There is one fragmentary report of a single Tiger on a road and the suggestion that the Commonwealth troops tried to stalk it with a Pheasant. But no records have been found of the two ever having an engagement. So as yet I've not been able to find out when the first meeting between these two famous weapons happened.

Image credits:
nzetc.victoria.ac.nzwww.desertrats.org.uk and en.wikipedia.org

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