Spitfire three-position gun firing button

[Shortways]

I am having a discussion with someone who tells me that spitfires equipped with 2 Hispanos and 4 Browings, could only fire all 6 weapons at the same time or the 2 cannons, but not just only the Browning guns.
Now I can argue that the 3-position firing button didn't have 3 positions for nothing and likewise for the o oO O markings on it, but I would like some written or schematic proof.

Does anyone have any original RAF text or schematic which would prove that all three options of firing were possible?
Or am I wrong and was the Browning guns only option not available?

We are discussing the Mk.IXc.

To my knowledge, the ww2 pilots used their Browning often quickly to make sure their aiming was good, before spending the very limited cannon shells.
And on top of that didn't like using to much ammo at the same time when not necessary, because the cannons on their own would do the trick just fine.

 

[mjfur]

Spitfire Manuals

Spitfire IX, XI, XVI, Here's one for you lancaster kicks *** Enjoy Micdrow

ww2aircraft.net

 

[fubar57]

To my knowledge, the ww2 pilots used their Browning often quickly to make sure their aiming was good, before spending the very limited cannon shells.
And on top of that didn't like using to much ammo at the same time when not necessary, because the cannons on their own would do the trick just fine.

I don't think trajectory would be the same between canon and MG so corrections would be needed

 

[Greyman]

I don't think trajectory would be the same between canon and MG so corrections would be needed

Proper harmonisation would negate any issue here (within reasonable shooting ranges).

Though the difference in muzzle velocity and bullet time of flight would factor in at some point with deflection shooting.

 

[fubar57]

This is to go with Post 2...... The B wing also introduced a new gun button: a rocker switch with three positions. This allowed the pilot to fire cannons alone, just the machine guns, or both together.

The Story of Spitfire Armament Modifications & Wing Designs

How to stop enemy bombers? More guns!By the mid-1930s, the Royal Air Force faced a serious challenge. Enemy forces were developing fast all-metal bombers, and the speed of aerial combat was rising rapidly.Pilots had only a few seconds to catch opposing aircraft in their gun sights. And in that...

www.spitfires.com

 

[SaparotRob]

Spitfire Manuals

Spitfire IX, XI, XVI, Here's one for you lancaster kicks *** Enjoy Micdrow

ww2aircraft.net

View attachment 894678

I believe that settles that.

 

[Greyman]

Interesting bit of trivia ... but the early gun button was three concave divots of equal shape (and feel).

Cases began coming in where pilots had inadvertently pressed the wrong portion of the button and fired the wrong combination of guns. So a modification was done up (Oct 41) where a piece of brass was sweated onto the middle recess to raise it up and differentiate it. HQ Fighter Command issued instructions 9 November 41 to all Squadrons and incorporation was left up to the discretion of the OCs.

Obviously, as seen by the photo included by Shortways, a solution was soon introduced into the production line.

 

[Shortways]

I believe that settles that.

Yes indeed! That is weird … my version of this manual doesn't even mention the button at all, while all other Pilot's Notes just describe the system in general terms.
Thank you very much!

 

[Shortways]

Interesting bit of trivia ... but the early gun button was three concave divots of equal shape (and feel).

Cases began coming in where pilots had inadvertently pressed the wrong portion of the button and fired the wrong combination of guns. So a modification was done up (Oct 41) where a piece of brass was sweated onto the middle recess to raise it up and differentiate it. HQ Fighter Command issued instructions 9 November 41 to all Squadrons and incorporation was left up to the discretion of the OCs.

Obviously, as seen by the photo included by Shortways, a solution was soon introduced into the production line.

That by itself points to the fact that pilots weren't to keen to spend all there ammo at the same salvo. I am wondering how difficult it was to operate with thick gloves anyway.
The internals of the system, I just learned, consisted of 2 valves; 1 connected to the top and 1 to the bottom of the "button"-pressure-plate. So pressing in the middle would have opened both valves.

It would be pretty hard if all 3 initially felt the same as you describe. I've never seen one of those buttons, but they apparently revised them or chucked them away.

Thanks for your info

 

[Shortways]

Spitfire Manuals

Spitfire IX, XI, XVI, Here's one for you lancaster kicks *** Enjoy Micdrow

ww2aircraft.net

View attachment 894678

Great! Finally a reference that actually describes using the guns. They hadn't bothered to do so in all previous Pilot's Notes. Thank you very much.

 

[Shortways]

I don't think trajectory would be the same between canon and MG so corrections would be needed

Yes would have had to be short range probably.

 

[Shortways]

This is to go with Post 2...... The B wing also introduced a new gun button: a rocker switch with three positions. This allowed the pilot to fire cannons alone, just the machine guns, or both together.

The Story of Spitfire Armament Modifications & Wing Designs

How to stop enemy bombers? More guns!By the mid-1930s, the Royal Air Force faced a serious challenge. Enemy forces were developing fast all-metal bombers, and the speed of aerial combat was rising rapidly.Pilots had only a few seconds to catch opposing aircraft in their gun sights. And in that...

www.spitfires.com

Yes that was when they switched over from the single button with the rotary safety ring to the "block" shaped one.

 

[Spits2]

There was a huge problem with cannons in the Australian theatre on the MkV tropicals so a lot of the engagements had to be done with machine guns.

 

[Shortways]

There was a huge problem with cannons in the Australian theatre on the MkV tropicals so a lot of the engagements had to be done with machine guns.

Yeah they were very likely still using the drum-fed system which were lying on their side (90°). That was later replaced by a belt feeder. There's a nice YT vid explaining this:

View: https://youtu.be/WDRpzvSghqA

 

[mad_max]

I don't think trajectory would be the same between canon and MG so corrections would be needed

You'd be surprised that the British 20mm and the ,303 were closer in trajectory than you would believe. The problem is the the spacing of the guns from each other.

 

[Spits2]

Yeah they were very likely still using the drum-fed system which were lying on their side (90°). That was later replaced by a belt feeder. There's a nice YT vid explaining this:

View: https://youtu.be/WDRpzvSghqA

Drum was only used for a short time during the BoB and soon found out to be a disaster.
No RAAF MkVc Trop problems were with gun heater ducting and other problems.

 

[Shortways]

Drum was only used for a short time during the BoB and soon found out to be a disaster.
No RAAF MkVc Trop problems were with gun heater ducting and other problems.

Check! Thanks for setting that right