ME-109 Propellor Cannon

lijn34 · Post by **lijn34** » Sun Jun 06, 2004 3:33 pm

Hello everybody, here’s a question of a technical nature. I’ve read somewhere on the internet quite recently that the ME-109 was equipped with a 20mm cannon firing through the propellor-shaft. Later I was wondering how this was done exactly. The propellor is connected to the engine’s crankshaft and, of course, you can’t fit a cannon through a crankshaft. So this problem is bothering me all night. Was there some sort of gearbox or another device (belt-drive) fitted between the engine’s crankshaft and the propellor shaft that allowed a propellor cannon to be fitted or what?????????????

If somebody’s got the answer to my question (or perhaps even technical drawings), I would be very happy to hear from you guys. So I don’t have to lie awake all night thinking about it.

Greetings LIJN

ratdog · Post by **ratdog** » Mon Jun 07, 2004 3:25 am

I saw an illustration somewhere that showed a cam driven device to the trigger on the gun that allowed it to shoot through the blades as they were spinning. I don't really remember where, but if you go to a site like HYPERSCALE, where they eat and breath planes, I'm sure some one will supply you with a diagram.............................Bruce

DeBaer · Post by **DeBaer** » Mon Jun 07, 2004 7:06 am

ratdog: its not about shooting through the blades here but shooting through the propellor-shaft i think.

yes theres a gearbox, and the barrel of the MG was as far as i know fitted in the space between the cylinders of the inverted-v-engine so that it could finally disembouge in the propellor shaft.
this was mainly done on the Messerschmitt Bf-109 F, G and K versions, with 15mm, 20mm and 30mm canons. other aircrafts also had this device(Ta-152)

even the russians used this method on their planes (Yak-3 e.g.), and the americans, too.

DeBaer · Post by **DeBaer** » Mon Jun 07, 2004 7:15 am

ok ive found a drawing on my hard drive.
http://debaer.freezope.org/files/canon.jpg
the cannon is marked with MG151, you just have to project the upper drawing on the lower full 109.
im sorry ive no better drawing.

Tony · Post by **Tony** » Tue Jun 08, 2004 10:44 pm

If you fit the drawing on the picture of the 109, it looks like the cannon mechanism itself is mounted behind the engine with its barrel fed through the propeller shaft.
Tony

DeBaer · Post by **DeBaer** » Wed Jun 09, 2004 5:20 am

did i say the opposite?
of course there cant be an mg between the cylinders, only the barrel is.

Matt L · Post by **Matt L** » Thu Jun 10, 2004 5:54 pm

The whole cannon mechanism sits on the cockpit floor between the pilot's knees- only the barrel projects forward through the engine block. It's the same with the 3cm MK108 in later G model 109s.