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#4552198 - 01/14/21 02:07 AM WW1 airplane machineguns  
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oldgrognard Online content
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Lifer

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I just watched the Blue Max again. I have a question about how the airplane machineguns were fired. They show them pulling a lever back to fire. That doesn’t seem right to me, but can’t find anything on the actual “pulling the trigger” on the machineguns. I remember once reading that von Richthofen told the aircraft designers to make the firing a trigger since men were familiar with the trigger shape to fire.

I did find this which reinforces my thinking that that lever pulling isn’t right.

https://nebraskahistory.pastperfectonline.com/webobject/B1608887-D086-4039-BB6B-594350452924



Anybody ?


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#4552200 - 01/14/21 02:25 AM Re: WW1 airplane machineguns [Re: oldgrognard]  
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The best I can find is this.


Twin guns synchronized by the Zentralsteuerung system in a Fokker D.VIII fighter. The "pipes" connecting the guns and the engine are flexible drive shafts
This was designed in late 1916 and took the form of a new synchronization gear without any rods at all. The cam that generated the firing impulses was moved from the engine to the gun; the trigger motor in effect now generated its own firing impulses. The linkage between the propeller and the gun now consisted of a flexible drive shaft directly connecting the end of the engine camshaft to the trigger motor of the gun.[40] The firing button for the gun simply engaged a clutch at the engine which set the flexible drive (and thus the trigger motor) in motion. In some ways this brought the new gear closer to the original Schneider patent (q.v.).”


And this which does seem to match the lever in the movie.

“ We placed a cog on the prop, that lifted another rod with a spring that released the firing cock of the machine gun,” Fokker explained. “The prop passed a given point 2400 times a minute, so with this machine gun that fired 600 rounds per minute we needed only one cam on the prop. The pilot had a lever that enabled him to make contact between the cam on the propeller and the firing mechanism. That was all.”


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#4552202 - 01/14/21 02:46 AM Re: WW1 airplane machineguns [Re: oldgrognard]  
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It is to give 'visual interest' for the viewer.

The real system had a linkage system interrupted by two 'gaps' - one near the cam, which was set closed by pulling the 'trigger enable' cocking lever, placing the linkages in mechanical contact with the cam follower, the other a hinged arm within the (airframe's) trigger group which used a Bowden cable from the control column trigger to pull an L-shaped, spring loaded lever into alignment with the linkage and the trigger actuator. The trigger actuator was pushed against a conventional trigger in time with the engine fitted cam, firing a single shot while the cam was in position to permit firing, releasing the trigger immediately the engine rotated away.

Each gun was also fitted with a cocking lever to clear jams and misfires, and to cycle the mechanism, but these could be hard to operate while flying an unstable fighter.

Other variants existed with cables or oscillating rods, but the Fokker synchroniser used one firing impulse per revolution (engine speeds ~1200 rpm), with around 2/3rds of the trigger activations being during the loading cycle and only around one in 3 being for a loaded chamber ~ giving around 400 rpm per gun on average - slightly down on the natural cyclic rate of the MG08 450-500 rpm.

Slight changes of engine speed/aircraft speed would result in different proportions of 1 round in 2, 1 round in 3 and one round in 4 revolutions and an irregular, variable rate of fire. This is synchronised fire.

Fokker aircraft had a basic HOTAS - with the control stick fitted with a static right side, with two triggers (one for each gun), and a 'lever' for the left handle which 'fine' controlled the air-throttle for the engine.

Fuel and air 'coarse' adjustments were on the cockpit sidewall.

#4552204 - 01/14/21 03:24 AM Re: WW1 airplane machineguns [Re: oldgrognard]  
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The pilot-operated guns in most (and all the ones I know about) aircraft were fired by thumb triggers on the stick, one for each gun, connected to the gun by a Bowden-type cable. Yes, that includes the ones mounted on the top wing. The director wanted the firing lever, and placed as high as it was, for one purpose...so the audience could see when Stachel chooses not to fire and to try to bring the enemy aircraft in. Of course that meant that they all had to be that way for the entire film.


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#4552205 - 01/14/21 03:25 AM Re: WW1 airplane machineguns [Re: oldgrognard]  
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#4552208 - 01/14/21 04:03 AM Re: WW1 airplane machineguns [Re: oldgrognard]  
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Great film and one that I've watched many times once I got over the fact that everyone was speaking English. biggrin

A bit of trivia: The film depicts northeastern France but was actually entirely shot in Ireland.


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#4552214 - 01/14/21 06:37 AM Re: WW1 airplane machineguns [Re: oldgrognard]  
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Fokker-Leimberger, https://guns.fandom.com/wiki/Fokker-Leimberger

Cyclic rate 7200+ rpm eek

None of the guns became operational during the war except the Siemens example which was tried on the Western Front with a victory using it during air combat.


There was only 16 squadrons of RAF fighters that used 100 octane during the BoB.
The Fw190A could not fly with the outer cannon removed.
There was no Fw190A-8s flying with the JGs in 1945.
#4552215 - 01/14/21 08:15 AM Re: WW1 airplane machineguns [Re: oldgrognard]  
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In german planes the machine guns by e.g. from Spandau were triggered by buttons at the control stick, two buttons for two guns. The levers at the guns were only cocked once to load the first round, the rest would work automatically by just pushing a fire button. Since the guns jammed now and then, pulling the lever again would (hopefully) remove the jam, they also had a hammer for stoppages.
Cold weather could also jam the guns, so the pilot usually moved the levers once to make sure, before going into action. The usual german MG 08 (made by Spandau) was basically the same as the Maxim guns, just with other alloys, sizes and some small improvements.

Last edited by Catfish; 01/14/21 08:21 AM.

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