Ardeer Aggie – the other Churchill AVRE

Hello everyone,

when I write the name “Churchill AVRE“, a lot of you fine folks will probably know what I am talking about: the well-known, engineering vehicle based on Churchill, armed with a 290mm Spigot mortar. While the platform itself isn’t that interesting, the mortar is regarded by many (incorrectly) as the ultimate derp (mostly because of its caliber). I mean, 290mm, that has to be the biggest bang on any non-arty vehicle around, no? I can already see some players drooling at the prospect of oneshotting pretty much everything with a MASSIVE HE shell.

That, of course, is not how its performance in WoT would look like.

You see, the 290mm might be a huge caliber, but the shell (called “flying dustbin”, but resembling more like a dumbell) weighted only roughly 18kg (with 16kg of it being the explosive part). For comparison, the 150mm shell the Sturmpanzer IV used (StuH43) weighted twice as much (38kg). It use less explosive though (8kg). This is how the 290mm shell actually looked:


As you can see, in WoT terms, we are looking at a shell with possibly good alpha, but very poor/negligible penetration. This, amongst other things was possibly the reason this popular vehicle was never implemented in the game. The other reason was that the 290mm demolition mortar (or rather, spigot mortar, if you will to describe it by its principle), was externally loaded, so that might cause some combat safety issues. Third major problem (both for WoT and in real life) was its range, which was very, very low (75-80m), plus its (again, very low) muzzle velocity. How it worked you can see here:



The Churchill AVRE was designed and pushed after the raid on Dieppe by a Canadian engineer lieutenant Denovan, because he (and other Canadian soldiers) learned during the ill-fated raid, how important it is to have an armored vehicle, capable of breaking thru various obstacles and strongpoints. The Churchill AVRE was the result of this development, but even so, it was far from perfect. Therefore, designers looked for way to improve the vehicle further and one of the results was the prototype Churchill AVRE, called Ardeer Aggie. And let me tell you. it’s one of those “Valiant” and “Covenanter” only-in-Britain things.


The essential problem of the original Churchill AVRE was the range: 70-80 meters is simply not enough. Therefore, the British came with a stunning idea to create a huge recoilless gun and fit it into the AVRE turret – the goal was to fling as much explosives in one shot on as long a distance as possible, without destroying the shooting tank in the process, preferably without having to load it from the front.

The prototype of this vehicle was using basically the same “flying dustbin”, but it was somehow modified and in the end, the caliber was changed from 290mm to 300mm, the projectile weight was increased from 18kg to 20kg. The barrel was made 3 meters long (300mm L/10) and went thru the turret (it was loaded from the inside). The range was increased to some 450 yards (411 meters). Of course, to fling such a shell so far, you need some serious charge. A LOT of gunpowder – much more than the gun would normally allow. The British engineers actually invented a pretty strange solution. In order to improve the gun recoilless effect, they did put a sort of “counterweight” behind the charge itself (a package of sand allegedly). When the gun shot, this charge was propelled violently to the back (away from the turret), compensating for the majority of recoil, bringing the amount of charge needed to more manageable quantitites. Needless to say, this was NOT a popular solution with the crew.

One vehicle was built and tested in 1943 and it was rejected. In the small turret, instead of just the shell, you now had to store a shell, the charge AND the counterweight. Furthermore, the gun was extremely noisy and shaky in the turret and if someone touched it when it was shooting, that person could easily recieve concussion and sometimes even broken bones, the gun was also very hot, so the crew had to be very careful around it, very hard to do in a rocking tank.

Another problem was that if there was some infantry advancing behind the tank or – heaven forbid – taking cover behind the turret on the hull, having a bag of sand fly from the back of the turret followed by a recoilless gun blast was not exactly healthy for them. The blast was also very long, so the tank was probably more dangerous to the friendly infantry than to the enemy one. They tried to solve it by installing some sort of blast collector on the back of the turret (so the blast was directed upwards), but for some reason it didn’t work.

In the end, it was decided it’s not worth all the trouble and that the 72 meters will be just fine (well, until the gun was replaced by the 165mm demolition gun). The prototype is currently standing somewhere in Britain.




63 thoughts on “Ardeer Aggie – the other Churchill AVRE

  1. Wow.. I would really like to see that in the game.. all together with that “slow-mo” mortar shell xD

  2. If WG introduces this tank they would have to give the gun 2 damage values, 1 from the HE bucket and 1 from the direct impact from the counterweight. Sounds like a great way to get rid of those pesky light tanks who end up behind your turret, don’t you think?

    • Most likely the sand would disperse pretty rapidly, countershot was employed in several recoilless rifles that were designed for use in confined spaces, and can be seen gaining in favor again today for urban combat in such designs as the AT4-CS.

      Mostly unrelated, but an interesting thing to note is that when you actually shoot one of these shoulder-launched weapons, the barrel doesn’t go up but down because since there’s minimal recoil and the main effect is that the mass that was pulling down the back end is suddenly gone (of course if it’s a panzerfaust or the infamous RPG-7 it;s the opposite). People have faceplanted because they don’t expect it. Something the trainers mentioned to us before letting us shoot the actual rockets after using the training ones.

    • Because a cloud of sand is *totally* going to do more than, well, sandblast the paint job tops… BTW I think the technical term is “countermass” – though modern designs apparently prefer water plus antifreeze for the purpose.

  3. Having to be loaded from outside is a myth, it was internally loaded though before going into combat they would load the first round externally as it was faster and easier.

      • Your wrongly assuming that as it was a mortar the loader had to exit the tank and load the round through the end of the barrel. Barrel cocked and there was a mechanical loading lift below the barrel. Loader had to expose no more of himself than a driver/commander.

    • Read your own source, co-driver breaks the barrel inserts round then closes it again, never has to get out of the tank.

      • quote ” The AVRE had been fitted with a sliding hatch in the hull, located in front of the turret. From this hatch, the loader would partially exit the hull to insert the round. ”

        what exactly you don’t understand in this sentence ?

      • He exposes his HEAD AND SHOULDERS, loading a weapon with 80 yard range That qualifies as loading from the outside, and is hardly a myth as you claim.

      • ” From this hatch, the loader would partially exit the hull to insert the round. This was accomplished by “breaking” the barrel- tilting the rear portion downward until the barrel was in a vertical position.

        The mortar round could then be loaded from below, using lugs to hold it in place until the barrel was repositioned, with the loader exposing only his head and shoulders from the hull during this process.”
        By breaking the barrel or whatever .he would still have to be partially exposed .. the anon is correct it seems .

      • As front of the mortar is outside of tank and shell had to be front-loaded, there is no doubt about the expression “external loading”.

        A discussion which parts of crewman are inside/outside of the vechile while loading … you made my day :-)

        • For some reason, if any part of my body was outside a tank in combat, I’m pretty sure I wouldn’t like it to be my head and shoulders…

          …left bootlace maybe, but not my fecking head…!

      • They had a 290mm Spigot Mortar inside the RE museum years ago when I worked there so you could actually see how it was loaded, there was not room for the loader to get his head and shoulders out when the barrel was broken.

        There was a loading tray that could be used which meant no part of the loader had to be exposed – this was awkward to use so mostly they were loaded by hand, the loader only having to expose his hands and for a short time.

        Lots of myths still circulate with much getting into books about how it was loaded – mostly believing a crew member had to exit the tank to load.

  4. Reminds me of playing the Cruiser II with the 3.7inch Howitzer. You can wait for some 5-10 seconds for the shell to simply arrive at its target at 500m distance, and then the enemy tank is in all likelyhood dead if he didnt move away within that generous timeframe, making something even slower…uuuhh, gimme that.

    • Or the Alecto.

      I have a replay here somewhere of a 580-someodd meter “snipe” on Sand River that takes several seconds to reach a stationary sniping T-28, its unfortunate victim.

      Them derp guns, sure are inaccurate ey wot.

  5. The donkey ran away.

    The contempory photos are at Royal Engineers Museum, Prince Arthur Road,, Gillingham, Kent, ME4 4UG

    The box at the rear of the turret seems to be angled and this may be the way that the balast sandbag was deflected upwards.

    • The picture is of a standard post 1945 Churchill AVRE (based on the MkVII) with a L9 165mm gun (saw service until mid to end of 1960′s).

      The box at the rear is the standard stowage box fitted to the rear of the turrets.

  6. Right chaps we can manage!

    No wait scratch that this idea was just silly xD

  7. As you say, only the Brits… It’s almost as if the more fiendishly complicated the solution, the more they like it. (see also: bouncing bombs off lakes and into dams)

    • …..bouncing bombs off lakes and into dams…. Yes that actually worked because of the back spin put on the bombs that helped them bounce and ensured that they stayed against the dam wall as the sank and when the pressure sensor triggered the detonation the explosion had maximum effect.

      • Soviets used the same technique vs ships . lol i want this to be an actual thing in Wows for soviet naval aviation :P

        • The US did it too-using B-25 Mitchells flying low and fast to “skip-bomb” Japanese ships.

      • It worked, but it was deemed a catastrophy afterwards because of how little damage it caused for so much preparation and and money.

        • Actually it obliterated the dam, and completely shut it’s output though the casualty was heavy for the operation.

          The problem was that the Allied did not follow it up, Speer wrote that while the Allied destroyed the dam they didn’t do much while the German was repairing it, which was a difficult work and could be easily disrupted by even low yield bombing.

    • Yes, somehow the Brits seemed to have had a liking for “unconventional” (to put it mildly) solutions. You can’t help but smile and chuckle whenever reading up about them, as long as it’s not as bad as the Valiant tank, where you just think “What the hell were those engineers smoking at work?” :D

      • I’m sure many of our weapons would make Hitlers eyes twinkle. They sound great to your average joe, but in practise are utterly useless for much military use!

        • I believe there’s not enough gigalomania in the British designs for Hitler to have liked them. :D

          • Project Habakkuk – the proposal for a 2.2million ton aircraftcarrier/iceberg/island

            That’s right on the scale that he loved!

            • Habakkuk was actually sound in principle (though habitability might’ve been so-so), but then someone crunched the numbers and realised the refrigeration plant needed would consume more steel than your average bog-standard carrier…

            • It was also hard to repair once a large chunk of ice left the ship while the ship was at sea. Too many things HAD to go right for the ship to remain in tact. Plus the steel issue and the issue with how long the construction would have taken.

            • One critic apparently also pointed out the amount of wood pulp needed for the “pykrete” ice would have been substantial enough to meaningfully affect paper production…

            • Indeed it was technically viable, and probably would have been somewhat effective from a military point of view, however, the scale it was at was simply too big for the time.

              Ignoring the obsene material requirements, another significant issue was building the dammed thing – the only place it could feasibly be built was Canada. There you are limited to doing most building work during the summer months, however the sheer size of the final design was estimated to have taken the best part of 3 years; and that was with a sufficient level of manpower to do the building, which there probably wasn’t.

          • Barnes Wallis devised the Bouncing Bombs used in the raids on the dams in Germany. He got a Wellington to aid in developing the bomb by pointing out that he’d designed the aircraft. He also designed the Highball bouncing bomb, a smaller version, meant to be carried two to a Mosquito, as an anti-shipping bomb. As mentioned above, they used backspin to promote a bounce and to keep them on line. The German bouncing bomb used a rocket booster, and no backspin. It tended to go further than Wallis’ bombs, but were not as accurate.

    • Bouncing bomb used in damn buster operation not only worked, it worked far beyond other weapon’s effectiveness.

      And there’s a good reason why they had to resort to it,

      Torpedoes don’t work, because the German was not stupid enough and deployed multiple layer of anti torpedo nets to protect the damn.

      Bombing the damn from above with direct impact bombs is ineffective as well because the damage is limited if you just bomb it from above owing to dam structure shape and also because of the difficulty of getting a direct hit.

      They didn’t develop the method and technique for the heck of it,
      They did so because there were NO OTHER effective method to do so at the time

  8. I’ve mentioned Ardeer Aggie a couple of times on the NA forums, without much of a bite. They were absorbed by the charms of the Petard spigot mortar, and blind to the Davis-gun-style recoilless Aggie. The spigot mortar itself was devised by a Colonel Blacker, and the concept produced the Blacker Bombard, Hedgehog anti-submarine mortar (and Hedgerow derivative) and the PIAT, as well as the Petard.

  9. Slightly OT but near where I live is one of the sites where Canadian troops practiced for the D-Day landings – “The Atlantic Wall” at Hankley Common, Surrey. This 100m long structure still shows signs of damage from Churchill AVRE’s and “Double Onions.” If you live in the area it’s well worth a visit as much of the site remains intact. Seeing a 1000 lb “Double Onion” being detonated must have been quite impressive.,_Hankley_Common,_Plaque.JPG

  10. The Churchill AVRE compared to KV-2.
    The KV-2 HE in WoT is the OF-530 HE fragmentation and it has 5,5 to 6,5 kg of HE but the older just HE shells on the KV-2 had up to 9kg of HE and I think they weren’t as effective. The Churchill AVRE’s 290mm spigot mortar fire the flying dustbin and it had 12.7 kg of HE in it. Comparing the only HE rounds the Churchill AVRE has 1,4x the ammount of HE than the old HE round on the KV-2. So calculating from that the Churchill AVRE could do like 1250 to 1300 damage, have lousy pen, flight time and possibly accuracy. So all-in-all I would love to see it as a tier VII premium.

      • Not really relevant (‘cept for ballistics maybe), in-game HE “terminal effect” specs seem to be pretty directly proportional to the payload. Makes sense enough as the fragmentation would be well-nigh irrelevant against armoured vehicles and most such shells would’ve been fuzed to go off right on impact anyway, excpetions presumably mostly being of the “anti-concrete” delay-fuzed semi-armour-piercing sort.

  11. Maximum range of Churchill AVRE`s Petard was circa 210 m, with mortat at 30 degrees elevation. Often quoted 80 m (or yards) was effective range – at further distance hitting a target was pure luck. But in WOT realm AVRE could do it`s work, acting as something between the tank and the artillery.

    • Its still considered state of the art equipment around here, especially with the cutbacks…

      Its more likely its a fence running around an entire base rather than just the tank.

  12. I live less than 100 meters from that Churchill AVRE at the bottom. It’s at the Royal School of Military Engineering in Chatham, Kent. :D

  13. Um, is it worth mentioning that the British also experimented with a 7.5 inch gun on the chruchill, along with the 6.5 that would become the 165mm?

    • The Churchill is inside the barracks, and I would have to get my dad to ask the guards to let me in. But I will see what I can do :)

      • Its actually in the grounds of the RE Museum, no chance of getting inside as it has long since been welded and rusted shut (I worked in the Museum in 1995)

  14. Does anyone seeing this as a possible premium, or, and this is just me getting carried away here, an arty piece at high tier (Unlike the others it would be slow but it would have the full armor of a Churchill and thus be somewhat well-protected for an SPG, the range on the mortar would be short but the radius for splash damage would be HUGE)?