Allied 'through the prop' firing

[kration]

A bit of a wierd query, but 'through the prop' firing of guns seemed pretty standard on axis aircraft - BF109, FW190, Zero etc...

But I was trying to think of allied planes that did the same. The only ones I can think of are:
P40
Fairy Swordfish
Vickers Wellesley
P39 Airacobra
P63 Kinccobra
Helldiver (prototype only)
TBF Avenger (early versions)

Any others? (just realised I've not counted French planes. Also, which Axis planes with forward firing guns didn't have some going through the prop).

It's strange what queries come into your head - I probably need to get out more.

 

[BombTaxi]

By 'through the prop', I presume you mean synchronised weapons firing through the propeller disc? Most Russian fighters in the LaGG, La, Yak and MiG series had such a weapons fit (as well as weapons firing through the spinner), British and American fighters tended to concentrate weapons in the wing as far as possible.

Would I be right in thinking that concentrating weapons in the fuselage allowed for thinner wings, and therefore a boost in performance

 

[tomo pauk]

Well, the most important allied planes featuring a 'centreline armament' are:
Yak-1, -3, -7, -9
LaGG-3
La-5, -7
Mig-1, -3
P-36
early P-51s did have a pair of LMGs synchronized

The other, not so numerous ones:
P. 11
IK-3

 

[kration]

Good points. As with my forgetting French Aircraft I'd also forgotten about Russian ones too.

I suppose rather than subdividing between Allied and Axis, my query was probably why was it uncommon in Brit/American aircraft, but common with other nations.

Good point re. the P51 - the Allison engined ones did have the synchronised guns. Was there a problem of fitting synchronised guns with a Merlin engine?

So to my list of Brit/American aircraft I could add the P36 and P51 (Allison engined)

 

[davebender]

This is really about aircraft engine design. You need a hollow prop shaft.

The Hispano-Suiza 12Y V12 had a hollow prop shaft. French fighter aircraft used this feature.

 

[tomo pauk]

...
Good point re. the P51 - the Allison engined ones did have the synchronised guns. Was there a problem of fitting synchronised guns with a Merlin engine?
...

Don't think Merlin impeeded the instalation of the hull guns, but the fact that synchronised MGs were of to light a punch.
So the people responsible for upgrade of P-51 decided to delete LMGs (along with synchro gear) and locate 4, later 6 HMGs out of propellor arc.

 

[mad_max]

You'll find that aircraft with the guns firing through the propeller arc have 3 bladed props. Easier to synchronise guns through 3 blades it seems and/or have less of a reduction of rate of fire.

 

[claidemore]

You'll find that aircraft with the guns firing through the propeller arc have 3 bladed props. Easier to synchronise guns through 3 blades it seems and/or have less of a reduction of rate of fire.

Good point!

 

[Wildcat]

You can add the Buffalo to your list mate.

 

[D.James]

The SBD Dauntless featured dual synchronized .50's.

The TBD Devastator single .30 cal, mostly field modified to .50 cal.

Already obsolete by Pearl Harbor, the P-36a Hawk was responsible for two victorys there, and saw continued service with the British as Mohawk 75 in the far east as well as captured french versions sold to Finland by the Germans were they were fairly successfull.

 

[Colin1]

...the Allison-engined ones did have the synchronised guns. Was there a problem of fitting synchronised guns with a Merlin engine?

There may have been, but possibly a question of familiarity, the Allison had already seen and done engine-mounted guns from the same installation in the early P-40s.

 

[Clay_Allison]

This is really about aircraft engine design. You need a hollow prop shaft.

The Hispano-Suiza 12Y V12 had a hollow prop shaft. French fighter aircraft used this feature.

And since the Klimov was based on the H.S, it did too.

 

[tomo pauk]

This is really about aircraft engine design. You need a hollow prop shaft.

The Hispano-Suiza 12Y V12 had a hollow prop shaft. French fighter aircraft used this feature.

It's easy to have a hollow prop shaft.
The main thing to consider is the layout of other things at front back part of the engine. If those things (alternator, pumps, supercharger...) stand in a way of a gun/cannon itself, then moteur cannon option is out of question. Eg. the Jumo inline engines were not able until 1945 to mount a cannon betwen the 'V of the engine because of the above reason.

 

[Colin1]

It's easy to have a hollow prop shaft

Not THAT easy
you need to consider

overheating
vibration

problems that plagued the Bf109 installation from the E through to the G

 

[claidemore]

Question pertaining to original post in this thread: does "through the prop" mean, through a hollow prop shaft?
Or synchronized guns firing between the prop blades?
Or both?

There was a second question in original post as well, which axis planes did NOT fire through the prop?

 

[tomo pauk]

Colin, was the hollow prop shaft the cause for those problems?

 

[Negative Creep]

Gladiator
Blackburn Shark
Buffalo
Albacore
Fairey Seal
Heart/Nimrod/Fury

Pretty sure the A36 did as well?

 

[Vincenzo]

There was a second question in original post as well, which axis planes did NOT fire through the prop?

all italian SE fighters have 2 .50 synchronized, the Ro 37 (SE recce for army) had 2 .30 synchronized, and the lone the Ba 65 (SE attack plane) have the weapons in the wing (if i remember right)

 

[Colin1]

Colin, was the hollow prop shaft the cause for those problems?

I would say a prop shaft
hollow or otherwise, is an integral part of the engine. It is the heat and vibration from the engine that would cause those problems.

There may be a better technical explanation as to why it isn't but I can't think of one.

 

[kration]

Question pertaining to original post in this thread: does "through the prop" mean, through a hollow prop shaft?
Or synchronized guns firing between the prop blades?
Or both?

There was a second question in original post as well, which axis planes did NOT fire through the prop?

Basically, I meant firing anywhere within the diameter of the prop i.e. both synchronised and hollow prop shaft. It was just an idle thought, but many Brit/US planes had guns in the wings only, and I could not think of many that varied from that.