Me 109 and cannon trough prop-shaft

[Kutscha]

Originally Posted by Ruy Horta

Maybe it is a Spanish concept, with Hispano-Suisse engine and cannon?

Might be for the windscreen sure looks like a 109's.

A H-S 20mm simular mounted
http://arsenalvg33.free.fr/hs404.htm

[fran]

Hello all,
It is a Me109J with Hispano engine and Hispano cannon.

Regards

[mkb42h]

does anyone have a link to a diagram of the daimler benz mounting? i have never been able to understand how a cannon can be mounted in an engine, fire through the hub, and be servicable, removable and belt fed.etc photos would be nice.

[ArtieBob]

IMHO, your problem in understanding is that the gun is not "inside" the engine. The breech mounting was aft of the engine crankcase and cylinder with the barrel and blast tube run between the cylinder bank vee. In the late Bf 109s, I believe the breech of some weapons extended into the cockpit to the point that rudder movement was impeded. The engine has a reduction gear which offsets the propeller centerline vertically from the crankshaft. The prop shaft is hollow and sealed so the gun is isolated from the engine internals, fluids, etc. If you look closely at the H-S drawings, I believe you can make out these features. Of course the DB engines were inverted vees, but the concepts are similar.

Best regards,

Artie Bob

[Kutscha]

Sorry for the large images.

The red line is the axis of the cannon tube.



Cannon mount in a Bf109F

[Paul E.]

Artie Bob is correct. It is difficult to think of the barrel of the weapon passing through the engine until you realize that the reduction gear that most if not all aircraft had then caused the axis of the propeller shaft to be offset enoungh from the crankshaft axis that the barrel axis passed between the V created by the two banks of six cylinders each. It's actually very simple and more fighters would have done it if the actual mechanism of the weapon typically hadn't been so long, causing it to intrude into the controls in the cockpit. The 30mm MK 108 cannon used in later Bf109s and TA 152H-1 had a shorter receiver (mechanism) and barrel made possible by a shorter cartridge than usual for this caliber weapon. That's why the ballistics and accuracy were modest (lower velocity and therefore more drop over a given distance) compared to a normal 30mm cannon.

Paul

[Kutscha]

It is not hard to understand as the cannon would interfer with the rotating crankshaft and the con rods.