Purpose of this blog

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

Sunday, June 24, 2018

Tandem HEAT warhead

In the years prior to the Second World War the Swiss inventor Henry Mohaupt started work on the Munroe effect, and is credited with developing the hollow charge anti-tank projectile. Although this is a bit of a generalization as there were many people thinking along these lines and may have also held the claim. The British Army embraced the idea of the HEAT projectile and began to work with it, resulting in a 2" No. 68 anti-tank grenade. The Germans were not far behind however by now with the war in full swing the British began to see themselves as having a technical advantage over the Germans with this technology.
The No2 68 Grenade was fired from a standard cup discharger on a SMLE.
To this end the British began to work on HEAT projectiles for a quite a few applications. In the spring of 1942 a requirement was issued for hollow charge rounds for all field guns, and both the 3.7" Mountain Gun in service with British and Commonwealth forces in Burma, and the new 95mm Close Support howitzer. The latter was a new infantry gun made from a section of 3.7" AA gun barrel, a modified breech from a 25-pounder and the recoil mechanism from a 6-pounder. As it had the same calibre as the 3.7" howitzer, and would also be a howitzer, the British could not use their conventional naming system. To avoid confusion they metricized it and made the calibre 1mm bigger, giving it the name of Ordnance QF 95mm Howitzer. The same solution was used in later years for the 77mm on the A34 Comet.

A Churchill Mk.V. The tank mounted versions of the 95mm had a counterweight on the muzzle. If you look closely the bottom of the counter weight is flattened. Something quite a lot of people miss.
The 95mm came in two varieties. One fired a fixed round and one a split round. The fixed round version was used in tanks such as the Churchill Mk.V or the Centaur. The split round was designed as an infantry gun but would never see service. It would however be fitted to the Alecto self-propelled gun when it entered its brief service life.
Alecto's in Germany, armed with 95mm's.
The shells designed for both guns met a simple problem, the hollow charge warhead had to be detonated some distance from the targets surface to allow the jet to form, today we call this standoff. In these shells the standoff was calculated at 62.48mm. The fuse had to be at the front of the shell to impact first and trigger the detonation. However, the detonation needed to start at the base of the shell. In between the two was the shaped charge, which needed a hollow cavity to allow the jet to form. In modern shells this is achieved by micro-electronics and a wire, but such technology was not available at the time.

The two options open to the designers were a really long mechanical striker that ran down the centre of the round, or a detonating train. The latter was an explosive line that carried the explosion from the fuse down to the desired location.

At first the simplest option was chosen, the long striker. However, the width had to be limited to avoid interfering with the hollow charge, this meant it was extremely thin and would not function fast enough to maintain the standoff. A detonating train would be very complex and difficult to manufacture to survive even limited muzzle velocities.

In July 1942 a new idea was tried. This involved two hollow charges facing towards each other. The top one facing backwards (towards the base of the shell) was smaller and had a shallow cone angle. This was triggered by a simple direct-action fuse, and it would then fire its jet along the length of the projectile and hit a pellet which initiated the detention of the main hollow charge. Trials were held with a 6.35mm hollow charge, which could trigger the pellet at a range of 1ft. It was found this initial charge could be fired fast enough to avoid the smaller shaped charge being moved out of alignment by the impact of the projectile on the target. This type of charge has been on occasion described as a 'Spitback' fuse, although that is not an official designation.
3.7" howitzer in action in Burma in 1944
When a 3.7" howitzer was used to fire these experimental rounds the penetration of the main charge was found to be very poor, far below expectations. It was suspected that the revolution of the shell was causing problems, and this was confirmed when a test shell was spun up to 12,000rpm when fired. To get around the issue of spin the cone angle was changed from 80 degrees to just 45 degrees and the standoff distance lowered. At this point the requirement for field guns to be able to fire hollow charge shells was dropped but remained for the 3.7" and 95mm.

In the final design the nose charge was aimed to fire down a hollow tube that started at the apex of the 0.08" brass liner. At the base of the hollow tube was the pellet to cause initiation of the main charge. Twenty rounds were manufactured for trials and penetrated 90mm of IT80 plate, sloped at 30 degrees, or 77mm at 44 degrees. A trial production run of 2,000 rounds was ordered, with one small change, the liner was switched to steel. Of these 200 rounds were fired in August 1943 and achieved 110mm of penetration at 30 degrees. Not a single round was a dud, and all functioned perfectly. 
95mm HEAT round, in its fixed version for use in tanks.
 With all in hand main production was started by a different manufacturer of the 95mm HEAT rounds. Immediately problems started as proof testing failed. After fitting the fuses to empty 40mm rounds, and firing them through mild steel plate, which triggered the fuse, it was found that alignments were off due to the new manufacturer forgetting to use gauging properly during the assembly process. Equally the assembly quality was bad with some shells having their nose caps just placed on the round and not pushed home before being welded. The defect with the alignment of the fuse was fixed around May 1944.

In June of the same year a suggestion was made to change the No.233 fuse for a No.243 fuse. This would allow the use of the round on soft targets. However, trials showed that if the round was fired under 2,000 yards it would be a dud.

Problems with the shells continued when a further trial in the first half of 1944 fired 99 shells filled with an inert filling, but a live fuse. It was found that the filling was leaking into the hollow tube that the nose fuse was aimed to fire down. This would absorb the jet and prevent the main charge from detonating.

There is surprisingly little evidence of what happened to the 95mm rounds during 1944, there is no evidence that they were issued in Europe. As the rounds were listed as 'not required for service' in October 1944, it seems unlikely that they were ever issued. My best speculation is that the manufacturing problems persisted and that few, if any, rounds passed proof stages. Thus, the entire project was abandoned.


Image credits:
britainatwar.keypublishing.com

Sunday, June 17, 2018

Super Conqueror Kryptonite

Have you ever looked back at work you did when younger or looked back at your social media posts from your teen years and thought "What the hell was I thinking?". Well that is me today, and it is time to touch upon a subject we've covered at least three times on here, and this I hope will be the final time. This is also an apology as a young historian I made a mistake.
We are all aware of the "Super Conqueror" that is spreading like wildfire around the internet. Well after seeing it appear, as a model kit after its WOT release, I began to feel a bit like Dr Frankenstein, whose just applied the electrodes, seen his monster lurch to life, stagger down to the local village and now all you can hear is screams and see the glow of a massive fire. At this point I have no idea how to stop it.
 The WOT Super Conqueror is made up of three parts. The hull of a normal Conqueror, a new turret based upon a sketch I found, and a set of spaced armour plates that were employed upon a range target.
In WOT high tier heavy tank was needed. However, on the 4th of July 1946 Britain had officially stopped developing infantry and cruiser tanks and moved all armour development to the Universal Tank. It is also at this date they switched from the old pre-war General Staff numbers (Eg: A.22), to the FV number system. This left WOT with a serious problem and is the reason why they used the FV215 (HT) that they made up for a number of years.
Then I show up with a document that says the hull armour on the Conqueror range target was actually manufactured and would have been fitted for combat.

To get around the issues WOT had, they mashed all the components together and came up with something that could work, they just needed a name. This approach works fine for WOT. Even the model kit that has been produced is fine, as it's meant to be the range target (although the base model is the wrong marque of Conqueror). The recent addition of the range target to other "100% historically accurate" games is a bit more confusing though.

Where did I go wrong then? Well last week, for the first time in four to five years, I was reviewing the documents on the spaced armour with some colleagues over at tanks-encyclopedia.com. It was pointed out that my evidence was a bit suspect. Even at the first glance I could see this was the case. The original claim for the hull plates was in a proposed requirement, not an actual specification. The document on the range target trials did use the same name for the armour plates, which I had latched onto and used it as proof. If I had been a bit more thorough I would have read the entire document and seen the wording at the back.
Simply put there is no evidence that the hull plates were manufactured or built. The text in the trials report implies that the hull plates were built for the trials only. Granted it is only implied, and you could read it to say the hull plates were actually for service. However, I feel that the phrasing indicates this was not the case. Now it maybe that someone will find a document listing the hull plates as produced, but at this time it is looking unlikely they were. I would also be careful about claims otherwise as these hull plates are unlikely to have left much, if any records, even in a fully complete archive, which the UK archives are nowhere near.

These were some of my earliest discoveries. Luckily, these days, I have become more thorough and over the years and learnt better methods of note taking, documenting and cross checking.

Therefore, I can only apologize for the mistake I made when I was younger and impetuous.


Sunday, June 10, 2018

No Big Bang

During 1940 Britain came under sustained bombing from the Luftwaffe. Its widely recognized today that an average of 10% of bombs that were dropped on the UK were duds, often called 'UX' or 'UXB' in reports, this stands for UneXploded Bomb. Today the number of bombs dropped on the UK is generally given in total tonnage of bombs dropped. For example, its often stated that 41,000 tons of bombs were dropped during the Blitz. This does not give a scale of how many bombs were dropped. Keep in mind that most of these would be 250 or 500kg high explosive weapons, with a rather large amount of incendiaries as well. But you've also got bigger 1,000kg mines as well. To give you an idea I posted this picture to my Facebook page a few weeks ago.
It is the bomb census data for the final quarter of 1941. If you look on the right hand page it gives you a number of UXB's by weight of bomb. In October alone, there were 100 UXB's and that isn't including smaller weapons like butterfly bombs or incendiaries. Each one of these had to be attended by a bomb disposal officer. Due to the bravery of these men, and other civilians during the period it was felt that existing medals and awards were insufficient. Thus, in September 1940, the George Cross medal was created.
Lt Andrews
The first award of a George Cross came on the 23rd of September 1940, technically the day before the medal was officially established. The recipient was Second Lieutenant Wallace Launcelot Andrews, for his actions on 26th of August 1940. Lt Andrews had been born in 1908 and was an architect before the war. He was called up in December 1939 and posted to the Royal Engineers. He was commissioned in January 1940. By August he was in command of a bomb disposal section when they were called to a UXB at Croham Hurst Golf Course, Croydon. The bomb was near the aerodrome. On closer inspection of the bomb it was found to have a new type of fuse, which was determined important and requested to be removed intact by the Department of Scientific Research (DSR). Hunched over the bomb Lt Andrews managed to get the fuse extracted about 1.5 inches, when it was pulled inwards by a spring or magnet. Several times attempts were made to pull the fuse, but each time the fuse was pulled back into place. Eventually Lt Andrews moved his section back to what he considered a safe distance, returned to the bomb and tied a string to the fuse discharger. He retired a short distance and gave the string a solid pull, attempting to rip the fuse assembly out of the bomb.
The bomb instantly exploded, hurling Lt Andrews through the air for some distance. Two of his men were also injured by splinters.

There are a great may stories of bomb disposal men working on bombs under incredible circumstances, such as Lieutenant Bertram Stuart Trevelyan Archer who worked on a bomb at the Anglo-Iranian oil storage facility in 1941. It had been hit by a stick of bombs that had all been duds. During the several hours he was working there two of the bombs detonated setting fire to the fuel storage, despite this Lt Archer continued his work.
There is also Doctor Arthur Douglas Merriman, a civilian. Dr Merriman was director at the DSR and would often attend extremely dangerous bombs and work on them. On the 11th of September 1940 at regent street London he attended a bomb. As work began on the bomb it was found impossible to remove the fuse, which then started ticking. This meant the clockwork on the bomb had been activated and after a pre-set, and unknown length of time the bomb would explode. Dr Merriman decided to remove as much of the explosive in the bomb as possible, this would limit the damage the bomb could do. The explosive was solid cast TNT which needed to be steamed to make it softer and pliable at which point it could be removed. As an example of how long this could last a previous bomb that had to be steamed empty had taken well over 12 hours (incidentally the Officer involved in that incident had also won the George Cross). In this case Dr Merriman worked on the bomb for four hours.
He judged the time and explosive perfectly, getting to safety seconds before the bomb exploded. The only damage the bomb caused, when it detonated, were some broken windows.
1000kg Luftmine
The incident that got me thinking about this subject were the actions of Lieutenant Harold Newgass. In November 1940 a 1000kg mine hit the gas works at Garston Gas Works in Liverpool. It was the same type of mine that was washed up earlier this year at Bognor Regis.
Lt Newgass' mine had hit a 4,000,000 cubic feet gas holder and passed through the roof. The parachute was entangled and keeping the mine suspended nose down.
The gas holder which had the mine stuck in it.
A quick explanation of how a gas holder works is in order to explain the situation. There is an island in the middle of the gas holder, this island has water around it allowing gas to be pumped into and out of the holder, with the water acting as a seal (a bit like the U-bend on a sink or toilet). The mine was in the center of the 65m wide holder and resting on the brick island next to one of the supports.
As the mine was inside a gas rich atmosphere no sparks could be allowed, so there was no form of illumination. Equally the atmosphere was such that a normal gas mask wouldn't work, and so Lt Newgass had to use breathing apparatus from the fire brigade, a piece of equipment he had no experience with. Finally, the fire brigade only had six bottles of air, each rated for thirty minutes. However, Lt Newgass would be using air much faster than normal due to the extreme exertion. Even just getting to the mine involved him wading through about 30m of waist, or even chest deep oily water. If he overestimated how long he had spent on the device there was no hope of him getting to safety quickly and he would be asphyxiated.
Lt Newgass
It took two days for Lt Newgass to defuse the bomb. The first three bottles of air were used on the first day to assess the situation, transport his equipment and secure and brace the mine. The second day he returned and encountered his first problem, the fuse access panel for the mine was resting against one of the steel supports for the gas holder. Lt Newgass had to rotate the mine, by hand, and if there was the slightest spark from the metal surfaces rubbing against each other, he and the surrounding area were going to vanish in a massive explosion.
No tragedy struck, and Lt Newgass was able to remove the fuse and detonators while using bottle number four. However, these mines also had a backup hydrostatic clock fitted. So, using his fifth cylinder of air Lt Newgass returned and removed the keep ring for this device, and rendered the bomb safe.

Image credits:
liverpoolecho.co.uk

Sunday, June 3, 2018

Busy Week

I'm sure there's a scientific theory somewhere which describes this phenomenon, but as you will most likely know I got made redundant a few weeks back. After two-three weeks unemployed I started back at my old job (with worse hours, I now do a 56 hour week). During that unemployed period I had nothing to do. The same day I started back to work I was contacted by two different companies I work for, and they asked for three pieces of work between them, oh and can two of them be done by next Monday please?
This meant I was unable to get an article finished for this week, so I've got to improvise a little bit, but I think you will like it. Next week will be back to normal.

First off, you'll remember a couple of weeks ago I wrote about the British assessment of the T-64. Well how well did they do? I showed the article to a Russian expert I know and he pointed out one glaring flaw. The glacis plate was actually under estimated by 105mm. Which by a curious coincidence is almost the same thickness as the fuel tank (110mm) that the British designers put there. They had to place the fuel tank there as there was no where else to put the fuel required for the gas turbine they thought fitted. Which was a bit of an error, equally the drivers position was nowhere near as bad as the British imagined.

Now onto the fun and games for today. Keeping with the theme of intelligence assessments of British Vs Russian cold war tanks, I give you a report on how the two equipments hold up:
  
page 1


Page 2
Page 3

So once again I'm sorry for the lack of article, and we'll be back to normal next week.

Sunday, May 27, 2018

Wingwalker

Late in the day of 6th July 1941, No 75 (NZ) Squadron Wellington Mk.Is took off from RAF Feltwell. Their target for tonight was Munster. The Germans had just launched their invasion of Russia, and Munster was a major transport hub. By striking it the British hoped to relieve pressure on the Russians.
As they plunged through the darkness the crews were struck, and more than a little relived, by how little enemy action there was. No night fighters, only a handful of search lights and just a few bursts of flak. They arrived at Munster and bombed the target, the city looked like it was in flames. On board one of the Wellingtons the pilot of the bomber circled the city so the crew could see what was going on. The pilot was Wing Commander R. P. Widdowson, whom was also the Squadron Commander, and his second pilot was Sergeant James Allen Ward. 
Sgt Ward
After Wg Cdr Widdowson had seen how the battle his squadron was engaged in had progressed they set course for home. Crossing the Zuider Zee Sgt Ward was standing with his head in the astrodome, keeping an eye out. Suddenly he spotted the first German resistance of the night, the shadow of a lone ME110 was closing from port. Sgt Ward keyed his intercom to warn of the impending attack. However, the intercom had broken in the previous few hours and no one had realized. The German plane raked the bomber with its cannon, spraying red hot shrapnel everywhere and fracturing a fuel line in the wing causing the fuel line to catch fire.
Wg Cdr Widdowson threw the plane into a dive to escape, at the same time Pilot Officer A. R. J. Box in the rear turret returned fire. This wild burst scored several hits on the ME110, and it was seen spiralling out of control. When the plane levelled out they followed the course of the Dutch coast to see how the fire would develop. Two of the crew were wounded by shrapnel, the nose gunner and Sgt Ward.

The crew attempted to put the fire out, first they smashed a hole in the side of the Wellington trying to get to the fire with a fire extinguisher, however their efforts were in vain. Next the crew tried throwing coffee from their thermos flasks at the fire, this did improve matters slightly by damping down the fabric around the wing but didn't extinguish the flames.
The damage to the Wellington after it landed at base.
The crew by now had decided to risk crossing the channel. At this point Sgt Ward volunteered to climb out of the astrodome hatch and crawl out to the fire to extinguish it. A rope was retrieved from the dinghy and tied around Sgt Wards chest, he tried to climb out the hatch, however it was very narrow and he wanted to take his parachute off. The crew refused to let him, and so he tried again and squeezed out. He was now sitting on the roof of the Wellington's cockpit while it was doing somewhere between 100-200mph. Sgt Ward then put the Wellington’s geodesic construction to good use, he kicked holes in the fabric and used the structure to stand on. Like this he made his way down to the wing. He was carrying a large cloth cockpit cover to help him smother the fire. However, it kept being caught by the wind and threatened to blow him off the plane. When he reached the wing, he began to crawl along it using holes made by the German's attack, and new holes he tore in the fabric himself. He was unable to stay close to the wing as his parachute was on his chest and this allowed the howling wind to get underneath him, once lifting him away and slamming him back into the wing. Eventually he managed to reach the engine and was now exposed to the full blast of the back draft from the propeller, but he carried on.
Sgt Ward's route along the wing of the plane
Sgt Ward got to the hole where the fuel and fire was coming from and tried to stuff the cover into it to smoother the flames and clog the fuel pipe. The second he let go the cover caught in the air flow and ripped away. Sgt Ward managed to grab the cover and dragged it back and rammed it back in the hole. Again, the wind tore it away instantly and although Sgt Ward grasped at it, he missed and the cover was gone.

The fire from the fuel pipe was now contained. There was nothing that could catch fire near the flames and so Sgt Ward made the difficult journey back to the cockpit. He was so exhausted by his journey he had to be hauled the last foot or so and into the cabin by the rest of the crew. As the Wellington neared the English coast the flames suddenly flared up, a small pool of fuel had collected inside the wing and had caught. Fortunately, this quickly died down again.

The German attack had also damaged the hydraulics which meant the landing gear was stuck and had to be hand pumped down. Instead of landing at RAF Feltwell, Wg Cdr Widdowson decided to land at Newmarket where there was a much longer landing strip. After circling the airfield Wg Cdr Widdowson radioed to the tower "We’ve been badly shot up. I hope we shan’t mess up your flare-path too badly when we land."
The Wellington thumped into the runway, and rolled forwards, it seems likely the brakes were also damaged as she rolled right off the end of the runway and came to rest in a barbed wire perimeter to the runway. Luckily no one was injured.

Sgt Ward was awarded the Victoria Cross for his actions. Unfortunately, Sgt Ward would not survive the war, in September of that year his bomber was shot down by flak and Sgt Ward was killed.

Image credits:
 For more on Sgt Ward's exploits, see this page, it contains some new pictures I'd not seen before.

Sunday, May 20, 2018

I spy a T-64!

Earlier in the week I took advantage of the fact I was made redundant and went to visit an archive. Whilst there I saw a document that I thought might be of interest. It is a technical assessment of the brand new Soviet tank, the T-64. Here is what the British thought the T-64 performance would be like. This is what the British were able to speculate from the intelligence sources they had, and these intelligence sources are varied and seem to have gone right to the heart of Soviet tank design.
"What's that? No I'm not British. Comradski!"
In September and October 1976 large numbers of a new Soviet tank were seen being issued to Group of Soviet Forces Germany (GSFG). The British had information about the T-72, and its planned introduction, and so thought this new tank was the T-72. This tank obviously sparked the British interest, especially as a large amount of information was being presented. Because of this excess of information, the Military Vehicle Experimental Establishment (MVEE) was tasked with creating a paper in December 1976. This paper involved the work of two British intelligence groups, the Technical Information (Army) and the Joint Air Reconnaissance Intelligence Centre.  MVEE had finished the paper by June, but were soon to be back at work as in November it was announced that the T-72 would take part in the Moscow Parade that year. The pictures immediately caused a concern, as all the agencies expected to see the tank they had identified beforehand, but it wasn't. It looked different. Initially these two tanks were known as the "GSFG T-72" and the "Moscow T-72", but intelligence data quickly identified the "GSFG T-72" as the T-64.
TI(A) and MVEE drew up a fully detailed 1/10 scale plan of the tank based on measurements from photographs. The internals were worked out from a variety of sources including defectors and a photograph of a turret trainer. The latter would have been used in class rooms to help instruct crew. How the British got a hold of this picture is an interesting question, as it seems that at least someone in tank design, or tank training school was spying for the British.
The turret trainer
Equally the British received a pair of recordings of the engine noises of the T-64. They analysed these and found out that most of the noises were in the high frequency range of 4000-80000 Hz. This, it was worked out, corresponded to a gas turbine engine with twenty compressor blades producing 800hp with a shaft rotation speed of between 12000 and 48000rpm. The British speculated that it might be a modified version of a MI-24 Hind engine that had been fitted to a tank. There were other sounds on the tapes that indicated an auxiliary power unit was fitted, which was a 6 cylinder four stroke engine running at 4000rpms producing some 75hp. This it was expected could be used when the tank was snorkelling to propel the tank at 0.5mph to cross the river.
But no T-64 was actually fitted with a gas turbine, so the likely source for these tapes is the Object 219, which was a prototype T-80. This would indicate that someone within the Soviet tank design departments was actually spying for the British, as a secret Object test bed vehicle isn't likely to be driving down the main road regularly enough for a spy to position themselves to make a recording.

This tape and the subsequent analysis did lead to some knock-on effects in the British version of the T-64. Due to a gas turbines high fuel consumption the British loaded the tank down with extra fuel to maintain a 500km radius of operation. This was achieved with some 920L of fuel in external tanks, which the British could see and measure. These due to the way they were linked by exposed fuel lines were considered for movement use, and not for combat use.  A further 360L was stored in the engine compartment, while a final fuel tank was placed on the drivers left hand side holding 1400L.

The drivers position was another oddity. While it was reported as having power steering the position was deemed to be very uncomfortable. This was ascertained by using the position of the episcopes the driver would use to see out of his tank while closed down. This in turn meant that the British knew where the drivers head would have been, and then using the "Soviet 95 percentile" of height (which meant that 95% of Soviet males would be close to this height), worked out how much space would be needed. The Soviet 95% figure was 5ft, 6in. The only place the foot pedals could be placed was on the nose plate, however the leading suspension arm’s torsion bar had to run through that space. This meant the pedals had to be placed higher up the nose plate than would be normal. It meant that the driver had to assume a hunched half crouch while reclining on the seat. It also meant that a set of duplicate pedals had to be installed for when the driver was unbuttoned. As well as the fuel tank the British designers placed some eight spare rounds of ammunition in the drivers compartment.
The loading arms removed for auto-loader maintenance.
The British also knew about the auto-loader mechanism as some photographs showed the loading arms of the auto-loader removed during maintenance. These, along with pictures of the ammunition, allowed the British to manufacture a loading arm to the same design as the Russian one and work out how it fitted into the tank. They estimated the ready ammunition would be between 28-30 rounds. The 125mm smoothbore gun was presumed to assume a loading position automatically after each shot and would have about 450mm of recoil travel. Total vertical movement of the gun was given as -5 to +16 degrees.
The copy of the loading arm the British built. In the left hand one you can see one of the wooden rounds that were also constructed.


The wooden rounds
Although the gun came with a thermal sleeve it was noted to lack a muzzle reference device which would affect the accuracy of the gun. The gunners primary sight was a variant of the TPN-1-21-11 sight with an optical rangefinder across the turret although no sign of a laser range finder was present at the moment it was expected to arrive on later models. The commander had at his disposal a TKN-3 day/night sight, with an assumed ability for hunter-killer automatic laying. All vision devices, including the drivers were deemed to be IR types, which needed active illumination by IR searchlights.

The armour was measured for the turret by taking the space needed for the internal layout and deleting it from the external dimensions. This gave a raw thickness. The report stated that there was no sign of any "Chobham style special armour” and suggested that the use of electroslag remelt was possible. In fact the T-64 had aluminium cores to its armour to save weight, while the T-64A had high hardness steel up until 1976 when corundum-ball inserts were used.

To assist with the hull armour values the report stuck with a Soviet standard of using some 50% of the total tank weight for armour. This figure is a bit of a pain to us in the modern day as we don't know what the total weight the British were using. Combat or loaded weight? But in comparison a Leopard 1 has 39% of its combat weight as armour, but a massive 57% of its empty weight. Equally one source I have has about 25% of the total weight of a Chieftain as armour but fails to mention what state the tank would be in when this was measured. However, it made sense to the British of the time as they knew what they meant. From that they came out with the following armour values for the hull:
Due to the turrets shape it was trickier to map, so MVEE took the simple route and sliced the turret into 100mm sections and plotted those thicknesses.
Cross sections of the turret showing armour thickness.
Because of the small wheels and torsion bar suspension hidden behind the wheels the side hull was seen as vulnerable to chemical anti-tank warheads such as HEAT, for this reason a series of paddles were fitted to the hull. These could be swung out a few degrees cover an arc of about 25 degrees with spaced armour. These were thought to be quite light steel and sprung so that they would be able to swing out of the way of a tree then spring back into position.
"Ulybka dlya britanskogo shpiona tovarishcha."
Other speculated protective features included a potential radiological sensor that would fire small charges upon detecting a nuclear bomb detonation, these charges would automatically close all the grills and louvres on the tank. In addition, an over-pressure NBC system was fitted, however the crew would wear grey NBC suits and individual gas masks.

The T-64 was seen as a step up in Soviet tank design, as well as abandoning their tried and tested technique of re-using the same components over and over again. Despite this it failed to meet the current Western standards. For example, the West were designing Chobham style armour into their tanks, and fitting thermal vision as standard, while the Soviets were still using IR. Equally on items like the NBC system, on British tanks a common air feed was provided to the crew stations meaning the crew could plug into air supplied from the tanks NBC pack, meaning a constant supply of clean cooled air was available to help with crew discomfort. In addition the drivers position was seen as particularly awful.

Sunday, May 13, 2018

The Little Helicopter that Could

On April the 21st 1944 a US L-1 observation plane was slowly flying along at very low level over the Burmese jungle. On board were the pilot and three British soldiers. This particular patch of jungle was Japanese controlled, so when the L-1 crashed, slamming down in to a rice paddy, and the bank of which ripped the landing gear off, the pilot and passengers were surrounded. To add to the troubles there were three Katana's that the pilot had obtained in the cargo space of the L-1, this would further enrage the Japanese and make matters worse if the Allied servicemen were captured. To add to the pilot’s woes the three British passengers were injured during the crash. The pilot's name was Technical Sergeant Ed Hladovcak, known as 'Murphy', simply because no one could pronounce his name.

The four Allies managed to move themselves about half a mile from the crash site, into dense jungle. They watched as a Japanese patrol appeared and began to search the area for them. Hiding in the dense jungle throughout the day, at one point they could see glimpses of the searchers legs through the undergrowth. By a miracle the patrol passed without detecting them.

There were other searchers out looking for the down airmen, the Allies had several tiny L-5 planes hunting for the missing aircraft. Sgt Hladovcak had done a bit to assist them by spreading a patch of parachute over the foliage hoping it could be seen, and it was. One of the L-5's dropped a note to the stranded Allies which urged them to move uphill as there were Japanese nearby. This began to get the downed Allies out of the Japanese search area. With the crash survivors slightly safer some supplies were dropped. The survivors would have to hold on for some five days before rescue would arrive, all the while suffering from infection to their wounds, heat and exhaustion with the Japanese beating the bushes for them.
Lt Harman, standing on the left, in front of the YR-4
The reason for the delay was a very unique piece of equipment was being prepared for the rescue. The USAAF in Burma had recently taken delivery of three YR-4 helicopters. One had crashed a month earlier, and the third’s pilot was wounded in action. This left one pilot selected to fly this mission, named Lieutenant Carter Harman. He had originally joined the Army Air Corps in 1942 and made what is usually regarded as a critical mistake, he volunteered for detachment to Stratford which was close to his home. It was also the location of the Sikorsky plant where he would learn to fly his YR-4.

The YR-4 like most early helicopters, was woefully underpowered, and had a tiny spare lift capacity. These features were not made better by hot weather conditions (like you might expect to find in tropical countries like Burma), or at high altitudes (again like Burma). Even under the best conditions the YR-4 had a ceiling of just 5000 feet. To get to the search base Lt Harman had to fly over some mountains which were actually higher than that. He also had to make the flight with no navigator and had to carry a load of spare fuel in jerry cans. Although at one stop over at a bomber base, the ground crew rigged a spare fuel tank from a L-5 into the cabin. This was to boost the range of the YR-4 sufficiently to reach the nearest large airstrip, and base for this operation. The YR-4 had a range of about 100 miles, in just four days Lt Harman managed to fly 725 miles to reach this base.
Sgt Hladovcak and the three other survivors had been directed to a location which the pickup could be made from, Lt Harman flew to this location and touched down. He could only carry one person at a time and so started ferrying the injured men. His destination was a sandbar which had been secured by British Commandos. This was to be a forward airstrip. Once there the wounded would be loaded onto liaison planes and flown to safety.

Lt Harman flew to the sandbank and linked up with an L-5 which guided him to the landing zone. However due to the heat and altitude the YR-4 could only just carry a single passenger even with the engine on maximum power. Lt Harman began to shuttle the most seriously wounded soldiers to safety. As he landed on the sandbar at the end of the first day the engine that had been running red hot seized with a clanking sound and emitted a cloud of vapour.
Lt Harman spent the night on the sandbar, and the next morning the engine had cooled and decided to work. Again, the YR-4 started to shuttle the men out. On the last run the Lt Harman picked up Sgt Hladovcak. However, the continued use of the landing zone had given the position away and the Japanese were closing. As Sgt Hladovcak scrambled aboard they could see Japanese troops approaching, Lt Harman pulled the YR-4 into a hover only to hear the engine begin to make the same clanking noise again, with the power loss the helicopter began to sink towards the waiting Japanese who were swarming below him.
Suddenly the engine settled down and returned to full power, and Lt Harman was able to pull away and begin the long flight back to base. For the first helicopter search and rescue mission in a combat zone, Lt Harman received the Distinguished Flying Cross. Carter Harman died in 2007 aged 88.

When Lt Harman finished his tour the YR-4's had no pilots and were laid up in storage. When, in January 1945, a B-25 crashed in the jungle two more pilots were flown out along with ground crew and spares to get the YR-4's back into the air. Before they could fly that mission the B-25 crew managed to walk out of the jungle themselves. The replacement pilots were ordered to stay in theatre for thirty days to train up new pilots and provide cover as needed. Only one pilot qualified on the YR-4, one Lieutenant Raymond F Murdock, simply because he was the smallest and lightest of the candidates and so the only one the YR-4 could lift along with an instructor.
Lt Murdock's first rescue mission came in March 1945. A US cargo plane had iced up and crashed into the jungle. Whilst searching for it a native had shown up with a written note giving the location of the one of the downed crewmen. The native guided a rescue party to him. At this point the native’s chief appeared and indicated via sign language that he knew the location of the rest of the plane and crew. Captain James L. Green offered to take the chieftain up in a Fairchild PT-19 trainer so that he could show them the location. Unfortunately, the chieftain became disoriented from flying and quickly became lost. After two hours aloft Cpt Green realised the situation was hopeless and turned for base, when suddenly the engine failed, plunging the PT-19 into the jungle canopy some five miles short of the main runway. As luck would have it the missing crew were sighted around dusk of that day and taken to safety. The searchers now turned their efforts towards finding Cpt Green's plane.

Around the same time as the original crew were being led to safety a C47 spotted the missing PT-19. However, in the dark nothing could be done. At first light a rescue party hacked its way through the jungle to reach the crash site. It took them a day and a half to reach the location. They found an unconscious and very badly injured Cpt Green, who had suffered a broken pelvis and jaw and was delirious with his eyes swollen shut. He also had multiple internal injuries. One of the rescue party was the bases surgeon, who immediately set about trying to save Cpt Green. The chieftain it was discovered had died in the crash, and been recovered and buried by his own tribe before the rescue party arrived.

The surgeon after examining Cpt Green was sure that he could not be moved any great distance. To do so would kill him. Equally he could not remain where he was. After being quizzed the surgeon stated that if Green was kept immobile, and the infection was under control he could last about a week, after that it was anyone's guess.

With that in hand the rescuers drew up a plan. They were in heavy jungle, on the side of a ridge line. The plan was to blast, cut and build a landing pad in the side of the ridge. This would mean clearing tree's (many around 150ft tall), then erecting a bulwark made from bamboo to hold together the soil piled up for the landing pad. All this was to be done by hand, although a powered saw did arrive to help with the tree cutting after a few days.

A large encampment appeared at the base of the ridge for all the help and support that came flooding in. Even so it still took nearly two weeks. Green's survival was due in a large part to a brand-new treatment, penicillin. By April the third in one of his overflights Lt Murdock announced that he thought he would be able to get in and would try the next day. Overnight there was a severe storm which threatened to wash away the landing pad. However, the bulwark held firm, although the steps created to allow workers to reach the landing pad were demolished by the battering rain.
The storm also caused humidity to rise and then the landing site was enveloped in thick fog. Lt Murdock wanted to get going before the heat rose too much and cut into what little lift the YR-4 could generate. Eventually the fog cleared around 1030 and Lt Murdock set off. As he sank through the trees he became fouled in a strong wind that blew down the hill, it carried the YR-4 past the landing pad, and the little helicopter didn't have the engine power to raise itself in the face of this wind. Lt Murdock aborted and came in again, this time flying with the wind. This nearly caused a disaster as the tail rotor clipped a few leaves on his descent, but both the machine and pilot held together. Then they were down, the pad had been built with a flat surface sloped at eight degrees to allow drainage, however the helicopter started slipping off the pad. Luckily several men were able to grab and secure the YR-4 before it slipped off.
Green was loaded into the helicopter, the co-pilots seat had been replaced so that a stretcher of sorts could just be fitted into the space when tilted at forty-five degrees. Cpt Green was strapped in. Lt Murdock instructed the ground crew to hold the helicopter down until he gave the signal. This would allow Lt Murdock to run the aircraft up to its full power. Of course, the ground crew would have to throw themselves flat instantly or run the risk of being hit by the helicopter.
The helicopter rose on full power, to a height of four feet. There it reached the maximum ceiling it could achieve with that load. To fly forwards would mean losing downwards thrust and the helicopter would drop slightly, but how much? With no other choice Lt Murdock pointed the nose downwards and dropped towards the trees. Because of the slope he managed to gain enough forward speed to clear the trees and return to the base. After dropping off Cpt Green Lt Murdock he attempted to return to his own base, however the engine sized halfway there, and Murdock was forced to make an emergency landing on a road. A truck towed the YR-4 back to base.

For his exploits during his tour of duty Lt Murdock would win a DFC.

Image credits:
More background to the YR-4 and more pictures here.

Sunday, May 6, 2018

To kill a Convoy

HOMO-03 was the designation of a Japanese convoy that departed from Hong Kong at 1700 on the 4th of April, 1945. Setting out was risky, however remaining was just as dangerous. On the 3rd an air raid of USAAF B-24's had sunk two transports and badly damaged a third. The convoy consisted of two transport ships, the 839 ton Tokai Maru No 2 (The first ship to bear that name was sunk in 1943 at Guam by a US submarine) and the 2193 ton, steam powered Kine Maru. The two transports were given a very heavy escort of five ships. In the lead was the destroyer Amatsukaze, and five corvette sized ships, these were the coastal defence ships CD-1 and CD-134, and the anti-submarine vessels CH-9 and CH-20. The convoy would proceed at about 12 knots towards Shanghai, and then onwards to Moji, a distance of only about 350 miles.
Such a heavy escort was normal, because by this stage in the war the Allied air forces were dominating the area.
The next morning the convoy was steaming along when the first of the US planes appeared. US intelligence had found the convoy overnight and had directed planes to attack. A flight of PBM-5 Mariner flying boats approached and began to make their attacks. I've not yet been able to find the squadron responsible, or an account of the attack however I did find this site which details the life of a PBM-5 crewman in the Pacific. It includes the following about a level bombing attack against shipping:
"VPB-27 and VPB-208 attacked a Japanese transport convoy at the mouth of the Yangtze River. We encountered heavy flak. VPB-208 went in ahead of us, which woke the Japs up, so they were ready for us when we got there. I prayed to be well—and I was well, just like that. But a hit by a 5-inch shell cut our aileron cables, so we couldn’t bank. Our flight engineer, Aviation Chief Machinist’s Mate Julius J. Jaskot was sitting on the back of his seat, with his feet up on the seat, to see what was going on, when a shell came in one side of the hull and out the other—where his legs would normally have been. It missed our gas line by just six inches. That same shell went through our propeller blades without striking them, as if it was synchronized—then it exploded. We must have been flying too low for the shell to arm."

The eyewitness also talks about torpedo attacks against Japanese shipping, which is well worth a read.

The result of this unknown squadron's attack on HOMO-03 was that the Tokai Maru No 2 was sunk.
Later in the day the USAAF took their first attempt at the convoy. B-24's and B-26's attacked and had cover from P-38 Lightnings. This attack sunk the Kine Maru. With no transports left to escort the convoy split into two groups. CH-9 and CH-20 returned to Hong Kong. They got back just in time to receive a large air raid from B-24's, the two escorts were damaged, along with two more coastal defence ships and a fleet oiler.

This left the two coastal defence ships, CD-1 and CD-134 along with the Amatsukaze. The later was not at full capability though. In January 1944 the ship had been torpedoed, which detonated her magazine, severing the ship in half just in behind the forward smoke stack. the US claimed her as destroyed however she drifted for six days before being recovered and towed to Hong Kong, where she had a makeshift bow fitted, along with several more AA guns.

The next morning at 1130 twenty-four B-25's appeared over the three escorts. The planes had come from Luzon, and after the long flight had found their targets. They consisted of planes from the 345th Bombing Group. The planes dove on CD-1 and CD-134. They were using skip bombing attacks. This is where the bombers make a high speed run at an enemy ship, when short of the target between two and four bombs are released with long fuses. These impact on the water and literally skip along the surface to strike the target ship in the side. Attacks are normally done in pairs with one of the B-25's hosing the target vessel down with its machine guns to suppress the ships AA defences.
The fate of CD-134. The B-25 in the picture is often identified as Ruthless Ruth, flown by Cpt Mikell.
CD-1 was hit by two bombs, one bounced off the water and exploded on the ships deck. The other hit CD-1 in the side and she began to sink. CD-134 was attacked by two aircraft, and suffered a single hit to the waterline, and rolled over and sunk. The exact credit as to whom got the kill is unknown as different sources give different pilots names. Lt. Lester Morton and Cpt Louie Avery Mikell are the two named. Lt Morton's fate I don't know, but Cpt Mikell survived the war, and in 1948 was taking part in the film "Fighter Squadron" when his plane went into a tail spin. Cpt Mikell bailed out, however he landed in Lake Oscoda, and was lost. His body was recovered a month later.
Amatsukaze before the torpedo hit.
Some ten minutes later six of the B-25's came across the Amatsukaze. The destroyer was alert and began firing on the B-25's as soon as they approached. The wall of flak scored a hit on one B-25 with a single 40mm round, the plane pitched in and hit the sea inverted, killing all on board. The other planes bombed the destroyer setting it alight, before retreating. The final group of six B-25's that had been at the location of the attack on CD-1 and CD134 had not dropped their ordnance. When they saw the pillar of smoke they set course and found the burning Amatsukaze, which was still steaming at full speed with all guns manned, despite being very obviously on fire.
Amatsukaze under attack, it is suggested that the large splash in the background is the inverted B-25 hitting the water.
This flight of planes was led by Captain Albin V. Johnson, who had only recently been made up to flight leader. The Amatsukaze put up a barrage of fire against Cpt Albin's plane, but despite being the target of the destroyers wrath he pushed forward with his attack. His plane riddled with gunfire Cpt Albin released his bombs, scoring a direct hit on the stern of the ship. Cpt Albin's plane roared over the sinking destroyer but couldn't gain height due to the damage sustained and ditched. He was later awarded a posthumous Silver Star.
A direct hit is scored on the Amatsukaze, starting the fire.
Despite the massive amount of damage she'd sustained Amatsukaze was still not dead. She limped on for another mile, where the crew found a reef. They beached her on it. For the next two days the destroyers crew attempted to stop the flooding, however on the 8th the weight of water was too much, and she slipped off the reef stern first and sank.

Further reading:
The most detailed account of the action can be found here:
https://airwarworldwar2.wordpress.com/2016/01/22/the-last-voyage-of-the-amatsukaze/
However that version differs from the more common version found here:
http://worldwar2database.com/gallery/wwii1331

Sunday, April 29, 2018

Killer of Everything

This week I start with a warning, a lot of the material in this article is drawn from sources that seem to be distinctly biased one way or another. Yet the results of the battles point to the likelihood that these reports hold, if not the total truth, then at least some degree of accuracy. With that in mind let us look at an African mass killer.

In 1965 Nigeria held an election, however the election was widely corrupt and shortly afterwards a coup was held by a group of military officers. This coup didn't seem to have many aims other than "get rid of the corrupt politicians", and the plotters quickly stood down. This left the presidency in the hands of the senior surviving member of the government, whom was also the senior army officer. By coincidence or design all the senior members of the coup and the new president were from a single tribe, the Igbo. This led to a counter coup within a few months and the persecution of the Igbos, as it was seen that they were striving to control the country.

This persecution led to most of the Igbo's retreating to their native home lands in the east of the country and caused a serious political upheaval and crisis. On the 6th of July 1967 the eastern region split from Nigera, declaring itself as the independent state of Biafra.
Flag of Biafra
The Biafra army wasn't the best equipped. A battalion had about ten to fifteen Second World War vintage Tommy guns, a couple of LMG's, HMG's and mortars of varying calibres. Later on, a platoons worth of assault rifles which had been captured from the Nigerian troops might be added for a shock platoon, if the unit was lucky. Otherwise the normal soldiers were armed with antique bolt action rifles, typically K98 Mausers.
The air force was in an equally bad state, having a single B-26, with this the Biafraian air force quickly started to launch air attacks on Nigerian targets, and actually could claim air superiority. The B-26 was based at Enugu air field and protected by a single Bofors AA gun. At about 0630 one morning in August or September 1967 the B-26 was being prepared for its days mission, when a Russian advisor flying a MIG-17 streaked across the airfield and strafed the bomber, damaging it.
The Biafraian B-26
It was clear from this moment that the AA gun used as the airfields defence would be insufficient, and a new defence was needed. This task was handed to the Science and Technology group based at the airfield. These were students and scientists from the University of Biafra (now University of Nigeria Nsukka). There was a second Science and Technology group based at Port Harcourt formed around the core of engineers from a Shell-BP facility. Later on both S&T groups would join together to for the Research and Production (RAP) organisation.

The answer to the MIG's was drawn up by the Enugu S&T group. Their solution was similar to anti-helicopter mines or somewhat similar to the British parachute and cable system used, briefly, during the Battle of Britain. This mine would be triggered to throw dust and debris up in front of the jet. Hopefully the jet would be hit, however as a consolation the dust might be ingested by the engine and wreck it. A metal bucket like device was constructed and several loads of debris were loaded and test fired. These gave ranges for the heaviest materials of about thirty feet, and the lightest up to 1000ft. This device was named a Dust Mine.
The "Dust mine"... I think. One massive problem with identifying items involved with this subject is pretty much every piece of ordnance is called an "Ogbunigwe" (see later for why). There is no clear distinct designation system, and invariably the device listed as an Ogbunigwe is just a simple metal tube. So this has partly clouded the subject matter.
Due to the shape and design several people have claimed the weapon used the Munroe effect, others reading this have suggested it was a HEAT warhead. A key point to the Munroe effect is that the cavity of the warhead is clear, the dust mines were filled. However, the shape of the weapon would indicate that a Munroe like effect is possible. Until someone dissects a dust mine then there is no way to say if it would act as a HEAT warhead.

By late September the Nigerian Army had gotten itself organised and was pushing on Enugu, causing the S&T group to flee and join up with its sister unit. By the 4th of October Enugu had fallen, and the exhausted Biafraian troops were retreating pursued by the Federal Army. At Ugwuoba Bridge a Biafraian officer attempted to rally a delaying force. Seeing a group of soldiers carrying some Dust Mines he ordered them to emplace the mines facing towards the other side of the bridge, he promised the troops that they could flee after the mines were detonated, just to see what their effect was. As well as hammering the advancing troops with blast waves and debris there is a report that a wave in the river was thrown onto the advancing government troops when the mines were detonated. Described by another account as "A tornado of dust, stones, fire and water" causing massive loss of life and destruction. The next morning a local man viewing the devastation called the dust mine 'Ogbunigwe', which is most often translated as 'Mass Killer' although there are other translations in a similar vein (such as the one used in the title to this page).

Meanwhile the RAP had been busy, they had decided to build a rocket. At first they attempted to build several full sized rockets, but they all failed. Then starting on small models of about six inches they built larger and larger rockets that worked. But the range was limited to some 200 yards. One of the scientists involved on the project said a man with a degree in economics gave them a tip that enabled them to reach a range of some two miles, although he fails to state what this tip was.

Whatever the result of the research, crude rockets which were simply tubes were soon being deployed. They were possibly tipped with Ogbunigwe. These crude rockets with no streamlining or thrust control were horribly inaccurate and unpredictable. The flight path was so erratic that sometimes the launchers found the rockets coming back towards them.
One of the rockets in its launch cradle, with room for a second rocket.
One such incident was in mid-October 1967 when a rocket was fired towards a pair patrol boats. A thick heavy smoke trail was drawn though the air, about halfway to the target the rocket veered to the right twice and was heading back. Then without warning it turned again, through 180 degrees and arced towards the second boat, which was 200m away from the boat that the rocket had been aimed at. The rocket hit the boat setting it on fire, and after a short time the fire reached the ships ammunition with deadly effect.

The famous author Frederick Forsyth was a war correspondent during the Biafra war, and witnessed a rocket attack when it was fitted with an Ogbunigwe. His account read "It spread death and destruction over a large area, and as usual the first division (...) were advancing in solid phalanxes of packed soldiery. An American who examined the scene afterwards estimated that, out of 6000 men who took part in the attack, 4000 failed to return."
Google suggests this is an Ogbunigwe barrage. I can't prove it one way or another.
The most famous use of these rockets was at an ambush at Abagana. The Nigerians were mounted in about 100 vehicles. One source says there were only 500 government troops, more claim there were some 6,000. The Biafraian troops set up their kill zone and saw the first of the Nigerian troops enter it, the young troops wanted to open fire immediately and were panicking from nerves. The Biafraian commander kept his troops calm and let the forward elements pass awaiting the main body of the column. His troops looked at him like he was committing treachery allowing the enemy to penetrate their lines. Whilst issuing the rocket operator with instructions, the soldier in his nervous mental state pressed the launch button. The rocket wobbled through the air and then impacted as luck would have it, on fuel tanker, filled with petrol for the convoy. The resulting explosion caused massive amounts of damage, and the rest of the battalion then opened fire. Accounts of the ambush often list Nigerian casualties around the 5800-5900 mark.
The aftermath of the Abagana ambush. A lot of accounts as shown above talk of single rockets being used. However from the wreckage shown, it appears that salvo's of rockets are normally fired, and the 'remarkable', or rather very lucky hits of single rockets described are down to volume of fire.
All the luck and homemade weapons couldn't save the Biafraian state and in 1970 the last pocket of resistance surrendered. It is to the last Biafraian commanders credit he refused to move to a guerrilla war and plunge the area into decades of conflict like so often has happened elsewhere in the world.

Image credits:
napoleon130.tripod.com and www.thescoopng.com