Sherman Firefly Main Gun Assembly

[Allan Richards]

Below are some photos of the work I've been doing to convert my Sherman to a Firefly. The long barrel is made from a 15mm copper pipe with strips of wood stuck to it with No-Nails. The wood has then been hand shaped with a plane and sandpaper before being covered in car body filler and finished off. The lathe didn't have the distance between centres to turn this length. The muzzle and mantlet end of the gun are turned from aluminuim. I had to do a lot of mods to the mantlet as the diameter of the breech end of the gun is 32mm whereas the supplied gun in the Armortek kit is only 24mm, so I had to make a new front to the trunion piece and the mantlet, but the gun will now recoil into the trunion. I also opened the front of the turret to allow the gun to be fitted and easily removed through the front of the turret. I am bearing in mind the maintenance aspects of the model, something I didn't do with the Tiger and now find causes the simplest of jobs to take for ever.

[Adrian Harris]

Great looking gun Allan

You mention that the barrel will recoil, will you be fitting a mechanism for this ?

What's the weight of the barrel/brake compared to the original ?

I've considered making a Firefly but wondered about the weight of all the barrel sticking out and how it would affect the elevation mechanism.

Adrian.

[Allan Richards]

Adrian,

To answer your questions, yes I will be fitting a gun recoil mechanism, but I've not designed it yet. I have a simple crank mechanism fitted to a sail winch servo on my Tiger but I want to get the quick recoil and slower recovery with tis gun.

The firefly gun weighs a lot more than the short thn walled tube of the original gun and I don't think the supplied elevation system will be up to it unless I balance the canterleverd weight of the gun, however I am reluctant to add weight like this. I was thinking of fittin a screw jack system like on the Tiger.

Making the Firefly conversion is not easy, there are a lot of differences and I havent even started on the turret radio box or additional hatch yet.

[Robert E Morey]

Alan,
Sorry about the lack of comments on your conversion. I too am interested in your work and photos. Don't get discouraged and stop posting!

I would recommend balancing the long gun tube with a weight inside the turret. This will make it much easier on the elevation mechanism and motor - be it a rack and pinion gear or screw type. Any long gun like the Firefly or Panther that is not counterbalanced will tend to rip itself and its elevation mechanism out during maneauvers in rough terrain if not balanced. Its a pretty easy calculation to figure out the counterbalance weight.

Just a thought.

Great idea on using copper tube for the barrel. Alum tube could also be used to minimize weight of the long tube..
Bob

[Allan Richards]

Robert,

I will have to counterweight the gun, I am going to try and do some of it by hanging the recoil mecanism off the back of the gun but I will endeavour to get the gun balancing on the trunions. I don't think that the Sherman gesr mechanism for elevation is up to the job and wold prefer something along the lines of the Tiger.

Allan

[Robert E Morey]

Allan,
Sorry to miss spell your name with only 1 "l". I agree the screw thread elevation is much better system than the gear and pinion.
Bob

[Allan Richards]

Robert,

Don't worry about the spelling - even I get it wrong sometimes. With a surname of Richards I'm also called Richard a lot of the time.

I checked out the speed of rotation of the gun elevation motor and its too slow for a screwjack system. I'd like someting thats a little faster than the Tiger motor really as the elevation is slow on that. I'll have a look for some web sites for 24v motors.

Allan