How big a difference is there in weight and space needed between the tank mounted version of the PaK 43 and the Panther's 75mm? I have a craving to build a E-10 and was thinking of bumping the gun up to an 88mm. I know, it's a paper panzer and I can do whatever I want, but I want to keep it in the realm of possibility. Weight might not be a problem .... beef up the suspension. Issue might be space for the breach /recoil system. The E-25 would be better able to handle both, but it looks too "normal" (jagdpanzer / hetzer - ish) The E-10 just looks sinister.

You could put steel road wheels in front to simulate load bearing.

You'd never fit the recuperator cylinders in there. Also recoil travel is your enemy in this case.

There are also the practical considerations of ammunition storage and loading. 8.8cm shells were much bigger and someone has to get them out of their racks into the breech ring within the turret volume, given the fact that much of the space is occupied by the rear of the weapon and assorted other turret equipment and crew members.

Think about the size difference between a Panzer 4 turret and a King Tiger turret. The 88 is larger, the recoil is longer and the rounds are much larger.

My what if would be to get a Wespe and put a Panthers 75MM on board. That is workable.

Open tops are simple. As long as the chassis not backed up flush against a brick wall the travel of the breach is not much of an issue. I mean they mounted (or planned to) 128mm PaK 44 on what was basicly a PzKw 38(t) . The E-10 and E-25 were intended on packing the Panthers 75mm. I thought the E-25 was suppose to replace the Jagdpanther , so one would think the big 88 would be an option.

Just saw something about the schmalturm being able to mount an 88mm. How much room did it have? Thought it was smaller than a standard Panther turret. Also they mentioned a PaK 43 with a new recoil system with no recuperator tubes on top and chambered for a round with a shorter, fatter shell to make it easier to handle in the confined space. Also, I think the fighting compartments are about (Scientific Wild Ass Guess) 240 X 160 cm for the E-10 and 280 X 170 cm for the E-25.

Plans were drawn up to mount the 88 in the Schmalturm beginning in October, 1945. The gun would have been way out of balance, and the space to load would have been insanely tight, but it was feasible. The Schmalturm had the same turret ring diameter as the Panther G, but was narrower towards the front, hence the name (schmal means narrow).

A good way to compare space required, is to put Marder 3 aside Nashorn. Then you realize how big/long Pak43 is. You can beef up a lot of things, but that just adds weight. Then you need to beef up tranny and engine, etc etc. Essentially, you will end up in bigger tank... Bigger gun is not an answer, the balance on the other hand, is.

Well, I finally got my E-10 .... And an E-25 for good measure.Using Ye old MkI Mod. 1 eyeball
the fighting area of the E-10 looks pretty close to a Panther turret. The E-25 close to a Tiger II. KwK 43 in the E-10 would not be feasible , but the KwK 42 would probably work. And would still be an improvement over the PaK-39. And the KwK-43 would be plausable in the E-25. Sooooo ..... Here is my E-25 Ausf B with the 88mm KwK-43, of Panzerjager Abt. 130, Panzer Lehr Div. Still working on the E-10 .... waiting for parts from KoaLa Land.

Another good visual comparison is to look at pictures of the PaK 43 auf Waffentrager and see how much space is taken up by the breech mechanism of the gun relative to the vehicle, with the Waffentrager having a significantly longer hull than the E-10.

If you want to" keep it in the realm of possibility" you wouldnt be building the kit in the first place, because Germany was in absolutely no position build any of these insane flights of fancy they had on the drawing board in 1945. I mean if accuracy is your goal and all....

"Another good visual comparison is to look at pictures of the PaK 43 auf Waffentrager and see how much space is taken up by the breech mechanism of the gun relative to the vehicle, with the Waffentrager having a significantly longer hull than the E-10." That is why the KwK 43 IS in the E-25. The Waffentragern were to be built (and the few that were built were..) on extended Praga chassis. Using a PzKw 38t (My waffentrager kit is still in the mail.) next to the E-10 the E-10 is 2-3 foot longer. The E-25 would be another 3-4 foot longer still.

The 7.5cm KwK 42 round is about the same length as that for the L/56 8.8cm. The L/71 8.8cm round was indeed considerably longer. Out to about 1,000m the armour penetration of the "long" 7.5 and "short" 8.8 was about comparable. Not forgetting that an L/100 8.8 was apparently proposed with, one assumes, an even larger volume chamber.

On my E-10 and E-25 I fitted the aircraft-style Bordkanone barrels with pepperpot muzzle brakes on the basis of higher-performance ammunition rather than a larger or longer gun.

Nice work , Peter. I like the screen skirts on the E-10. I heard that they were designing a version of the KwK 43 that had a new recoil system that did away with the huge recuperator tubes making the gun more compact, plus I think the plan was to up the powder charge too. My E-10 is on hold for the moment, waiting for parts from the land of the Koala.

All of the considerations listed above are valid. A larger caliber gun can be put into almost any turret/chassis. It would require changes to the recoil system to shorten the recoil and to get the system into the turret. Then you had to somehow account for the increased energy that gets transferred through the gun trunions to the turret ring, fire control system, crew, etc. An excellent example is the difference between 152mm gun-launcher mounted in an M60A2, weighing approximately 54 tons compared to the same system mounted into an M551 chassis weighing just 17 tons. The M60A2 could easily absorb the recoil forces that were not absorbed by the recoil system. The M551 is a completely different case. Having served in all 4 crew positions in a M551, the recoil when firing the 152mm HEAT round was "exciting" to say the least. It was just about guaranteed to knock the missile out of alignment, lift the first two road wheels completely off of the ground and there were cases of cracks developing in the turret ring. As long as there is room between the breech and the back of the turret, when the gun is "in-battery" to load the ammo, enough room for the recoil, and room for the crew you could mount almost anything you wanted. If the crew and vehicle will survive the result of too much gun for too little chassis, is the question. For those reasons I would never want to man a Hetzer!

Thanks, Timothy. First tanks I'd built for years and they turned out OK. I went off doing German subjects a long time ago but I've always liked these 2 Entwicklungsfahrzeug.

I wondered at first if the E-10 might have the automatic BK5 5cm gun firing APDS. In the end I just bored-out the BK5 muzzle and used it as a 7.5cm.

The gun barrels are actually 1/32, by Schatton Modellbau. I wanted to use their lovely MK103 barrel in the E-25 cupola, but realised it was much too small to fit an MK103 breech. There's some "what if" extra armour around the shot traps under the mantlets.

Of course we're surmising here that Germany would have carried on using HV KE rounds. Tungsten was pretty much non-existent and propellant short. HEAT rounds were available for lower-velocity weapons like the LeFH18. HEAT has the advantage that its effect is independent of impact velocity. Although trajectory and time of flight become problems with lower velocities, complicating firing solutions: aiming.

There was of course the real 8.8cm PAW600 and proposed 10cm PAW1000. These were lightweight, low-recoil yet high-ish velocity weapons which used less propellant and did not need massive mounts and recoil mechanisms. But were range-limited: 750m for the PAW600 Panzergranate. OK for an ambush predator like panzerjager. I suspect that had the war continued we were more likely to see more use of these.