Finnish tanks - design challenge

During the Continuation War Finnish Army acquired what was perhaps the worst tank in history, BT-42, by mating captured BT-7's with British QF 4.5" howitzers, calling these assault guns and using them in front lines.

However, how about more innovative approach. By end of 1941 Finnish Army had a large number of captured T-26's and BT-5/7 series tanks. Could these be modified for a) use as APC's b) AT-gun tractors c) tank destroyers, perhaps utilizing Soviet 76mm F-22 guns or French 75mm model 97 guns? Spare capacity in industry for modification work was available.

Jukra said:

During the Continuation War Finnish Army acquired what was perhaps the worst tank in history, BT-42, by mating captured BT-7's with British QF 4.5" howitzers, calling these assault guns and using them in front lines.

However, how about more innovative approach. By end of 1941 Finnish Army had a large number of captured T-26's and BT-5/7 series tanks. Could these be modified for a) use as APC's b) AT-gun tractors c) tank destroyers, perhaps utilizing Soviet 76mm F-22 guns or French 75mm model 97 guns? Spare capacity in industry for modification work was available.

Click to expand...

Sure, and inspiration could be gathered from how the Germans mounted various guns on just about anything that could move but was too small for a useful gun in a turret.

IMHO especially the BT5/7 chassis would be interesting for carrying the 76,2 mm F22 in a superstructure as a selfpropelled antitank-gun. Protection would only be against handweapons and shell splinters but the speed of the vehicle would be most useful in setting up "PAK-fronts" hit and run wise.

The French 75mm BTW is very interesting in this context. As I understand it was used to good effect as an AT gun by the French in the last weeks of the 1940 campaign and it was available in numbers. With its relatively curved trajectory it would never be an ideal AT gun but better than most other designs in 1940-41 and it would anyway launch a most useful HE shell. Why not mount it on a T26 chassis as an assaultgun (Italian Semovente like?), speed isn't as essential as for an SPATG. Protection would be well below desireable, but much better than nothing.

How about something like this? BT-7 with French 1939 Canon de 75mm TAZ mle.

120mm SP mortar carrier prototype was tested in late 1944:
http://forum.valka.cz/attachments/796/120mm.jpg

This is basically the same German conversion package but delivered onto two different chassis, namely the T-26 and BT-7.

Go look at the thread on a German SU-76.

Pounding the gun barrel over the engine deck (ala. SU-76 and Valentine Archer) would reuce its overall length and improve its turn radius in heavily-forested terrain.

What was the BT's ground pressure?
With light enough ground pressure, a BT conversion might have proved valuable as an APC. Considering the Finn's man-power shortage, any way to reduce infantry casualties on the way to the battle field would improve their performance. I am picturing something like the PBV 301 APCs that Sweden built on top of old (WW2-vintage) Czech THN medium tank chassis.

I guess that the Finns developed the BT-42 because they wanted a better tank and had the howitzers to hand. Given that they eventually replaced them with StugIIIs because of short comings in the tank they might have been better off doing a assault gun conversion instead. Then again a fair few less than successful tanks were built/converted during the war.

On the subject of French 1939 Canon de 75mm TAZ mle conversions, unless the Finns already had some or the Germans were prepared to ship them to Finland the conversion is a non-starter.

Redbeard said:

The French 75mm BTW is very interesting in this context. As I understand it was used to good effect as an AT gun by the French in the last weeks of the 1940 campaign and it was available in numbers. With its relatively curved trajectory it would never be an ideal AT gun but better than most other designs in 1940-41 and it would anyway launch a most useful HE shell.

Click to expand...

Note that there is little difference between the 1897 and the US M2/M3 used in the Lee/Grant/Sherman besides the recoil system and breech block.

Ammo 100% interchangeable.

It even had a HVAP round developed, the T45, but not standardized for production. At 500 yards, could penetrate 117mm of armor, almost twice what the APC round could do. 2855 feet per second