Understand that certain subject warplanes had a cannon which was positioned in the actual nose of the prop and curious if someone knows how that was accomplished design wise. How did the cannon barrel "fit" in relation to the actual engine in the plane?? Just curious and all feedback appreciated.

I've found a few pictures.


The gun mounted to the rear of the engine

quote:

Reflecting Messerschmitt's belief in low-weight, low-drag, simple monoplanes, the armament was placed in the fuselage. This kept the wings very thin and light. Two synchronized machine guns were mounted in the cowling, firing over the top of the engine and through the propeller arc. An alternative arrangement was also designed, consisting of a single cannon firing through a blast tube between the cylinder banks of the engine.

The Bell P-39 had a rear engine driving the prop through a gear box.

The BF-109 had the offset gearbox attached to the front of the engine. That cannon was mounted between the cylinder banks and fired through through the hollow prop shaft.

Complex for sure !
I still can't believe some of the early planes didn't have sinchronizers so you blew you prop off if you fired the gun !

OK, thanks for the feedback. It's amazing how war often times brings about the best in engineering and problem solving of all sorts.

quote:

Originally posted by Instructor:
OK, thanks for the feedback. It's amazing how war often times brings about the best in engineering and problem solving of all sorts.

The huge wealth of nations when applied to "defense" results in tens of thousands of the brightest scientists and engineers working on military hardware for entire careers. That is how you go from 2 bicycle mechanics flying a powered glider in 1903 to a jet fighter in 1943.

My grandfather remarked that he was born in the era of horse & buggy and the Wright brothers and he lived to see man land on the moon.

The previous post citing the Bell P-39 Aircobra is correct.

the BF109E/F models had a 15mm or 20mm Autocannon mounted behind the engine, the barrel mounted through a tube between the cylinder banks of the Inverted V engine.

The Daimler-Benz DB601 engine used is an INVERTED-V and the propeller shaft is inline with where a camshaft would be mounted in an "OHV" engine.


Rusty, GREAT PICTURE! the Autocannon you picture is quite clearly a MK108 30mm cannon, you can even read the "108" marking on the top of the hydraulic charging assembly.
This autocanno would have been mounted to a DB 605 Engine to be installed in a BF109G-6 aircraft.


I'll still refer to the DB601 Inverted-V engine as being a SOHC
(Single OverHead Camshaft) even though technically the camshafts are INDER the heads as the engine is installed

There were also a pair of synchronized guns mounted in the upper cowling.

On the "G" model (And later 109's) the "Through the prop hub" installation is less obvious, but on some varients the gun was actually upgraded to a more effective 30mm Autocannon

The cowl mounted guns were ELECTRICALLY "Synchronized"
using electrically primed cartridges to allow for a higher rate of fire. (yes, to avoid blowing the prop blades off)
The through the prop hub obviously did not need to be synchronized.

Another aircraft besides the Bf109 and the P-39 with a Cannon firing through the propeller hub was the French Dewoitine D.520, which has an Hispano-Suiza HS.9 20mm cannon in an identical arraingement to that used on the Messerschmitt.
but like the Bf109-G4 it had a limited ammunition supply, only 60rounds which lasted 10 seconds at the cyclic rate of the cannon.

Other aircraft with engine mounted cannon are:
Rogožarski IK-3 (Yugoslavia)
Yakovlev Yak-1 (Soviet Union)
Lavochkin-Gorbunov-Gudkov LaGG-3 (Soviet Union)

There were other expiremental and prototypes but...