The Synchronized Machine Gun.

[jerryw]

I read a copy of the book, "Flying Dutchman" by Anthony Fokker (1931) in which he devotes an entire chapter to, "I Invent The Synchronized Machine Gun".
However, I understand that Fokker's claim has been disputed in recent times. Are there any known references or discussion on this matter?

[proton45]

I have never heard this before...where did you hear about this?

[HoHun]

Hi Jerryw,

>However, I understand that Fokker's claim has been disputed in recent times. Are there any known references or discussion on this matter?

He had just not been disputed in recent times, but even back in WW1.

This thread shows a 1913 patent on interrupter gear:

http://www.ww2aircraft.net/forum/wea...ion-15659.html (RAF guns and ammunition)

However, the lawsuit against Fokker failed, possibly because his interrupter system would not only interrupt the burst when a propeller blade was in the way, but also continue it when the line of fire was clear again.

Fokker did however have to pay license fees to August Euler, who had patented the method of mounting a fixed gun parallel to the line of flight and aim it by flying the plane.

The designer of Fokker's interrupter gear was his employee Heinrich Lübbe, like Fokker one of the original Johannisthal aviation pioneers who was a assdious inventor whose main interest was aircraft armament (which had been the reason for Fokker to hire him).

I'd be interested in the account Fokker gives of this invention ... "Arado" by Kranzhoff has one photograph with Lübbe and Fokker standing over the cockpit of an Eindecker conducting shooting trials, and another one with Lübbe in front of an Eindecker, explaining the system to a group of aviation officers that includes Oswald Boelcke.

Regards,

Henning (HoHun)

[jerryw]

Proton45,
Copies of "Flying Dutchman" by Fokker & Gould are readily available from the the ABE BOOKS website.
The book has been reprinted many times, including paperback versions.
The 1931 editions have quite a few photos in them.

[jerryw]

Fokker's account (see below) is extraordinarily at odds with any description of his receiving help from anyone else! He is adamant that he did the whole job on his own and in very short time!

P.S. The Patent by Franz Schneider was lodged in England in July 1913 as No. 191316,726. It only runs to three pages and can be downloaded free from the Espacenet website. It is written in English.

[HoHun]

Hi Jerryw,

>Fokker's account (see below) is extraordinarily at odds with any description of his receiving help from anyone else! He is adamant that he did the whole job on his own and in very short time!

Interesting ... however, Lübbe was clearly Fokker's armament man, being made director of the Fokker-Waffenfabrik in Berlin in 1916, and he certainly was an innovative designer as he came up with a 12-barrel Gatling gun for aircraft use in 1918, and a 20 mm aircraft cannon in the early 1930s. He also held many patents on military and civilian inventions in the inter-war period.

Kranzhoff notes "The share in the remarkable profits from the production of about 42000 sets of synchronizers made it possible for him [Lübbe] to found the 'Versuchsanstalt für Waffen- und Maschinenbau' in Berlin, Potsdamerstraße 27 b in 1919". Unfortunately, he does not note if that was the inventor's share or if Lübbe had a share in the profits due to his management position at the factory producing the synchronizers.

Below the picture from Kranzhoff's book ... the German subtitle (obviously written by Lübbe's coworker Hebe) is "Fokker, Lübbe and me at the first test". It does at least suggest some close cooperation :-)

>P.S. The Patent by Franz Schneider was lodged in England in July 1913 as No. 191316,726. It only runs to three pages and can be downloaded free from the Espacenet website. It is written in English.

Thanks, I'll check it out!

Regards,

Henning (HoHun)

[Marcel]

Fokker's account (see below) is extraordinarily at odds with any description of his receiving help from anyone else! He is adamant that he did the whole job on his own and in very short time!

Remember, Anthony Fokker was known for his sheer arrogance and saw no trouble in using others for his own credit!

[jerryw]

Memo to Henning,
Can you resize that photo of Fokker and Lubbe A.S.A.P., please. It is far too big for the screen! If you reduce it to about 3.5 inches, it should fit.

[jerryw]

Below is an abbreviated version of the Schneider patent concerning a synchronized gun on an aircraft.
It is very hard to see how the Fokker "invention" differs, in principle, from this patent.
The other question is, if Fokker had thought he had invented a significant interrupter mechanism, why didn't he file a patent for it? By 1915, he was an experienced designer and manufacturer. He must have been aware of the possible wide-spread use of the device and therefore, the importance of protecting his rights by patent.
Also worth noting that Schneider's patent lists his location as "Johannisthal near Berlin", the same place that Fokker spent a lot of time during his early flying days.

[Marcel]

This is what happens if the system fails. A propeller from a Fokker D.XVI in the Dutch Airforce museum, Soesterberg

[HoHun]

Hi Marcel,

>This is what happens if the system fails. A propeller from a Fokker D.XVI in the Dutch Airforce museum, Soesterberg

Great illustration, thanks a lot!

One version of Immelmann's death is that his aircraft crashed after a malfunctioning synchronizer gear shot up his propeller, so it seems that this was a realistic danger. (I presume the worst case would be one blade being torn off, as the resulting imbalance would probably destroy the aircraft.)

Regards,

Henning (HoHun)

[Ferdinand Foch]

Whoa, thanks for the picture Marcel, I would have hate to have been the pilot for that aircraft. Dumb question, though, how (or if they did at all) did the Allies learn to use the syncronized machine gun themselves. Did they invent it on their own, or did they design theirs off of machine guns from captured German planes. Just curious.

[Marcel]

Well, I think the pilot was incredible fortunate not to shoot his prop off. I think it was a very short burst
I thought I read somewhere that they copied it from a captured E.III

[Avn-Tech]

Group,

I am sure that several people working independently on a problem would come to about the same conclusion. Hence more then one person could rightfully clain to have invented the interrupter gear and be legimite claim.

Remember that when Folker claimed to have invented the gear, WW I was going on and the government probably seized the rights for their use (So no patents).

Also remember that information did not travel as fast in early 1900's as it does today. So an invention in Europe may not reach america for a while.

When I first went into the Air Force, I had a Squadron Commander whose father invented the Cleco. He received no compensation since it was wartime, and then country need the invention.

Laterrrrrr
Avn-Tech

[Deanimator]

There were several synchronization systems which predated Fokker. Their problems were that they were usually coupled with guns that were difficult or impossible to synchronize by ANY system. The book "Flying Guns" goes into extensive detail on synchronization systems and why some failed and others succeeded.

Basically, closed bolt, short recoil operated guns are easy to synchronize because the timing of the firing cycle is highly predictable and consistent. Open bolt, delayed blowback, and similar guns are hard to synchronize because of inherent firing delays caused by lock time and bolt travel before a round is fired.

Easy to Synchronize:
Maxim based systems (MG08, MG08/15, Vickers, Russian Maxims, etc.)
Browning/Marlin
Browning M1919

Hard or Impossible to Synchronize:
Schwarzlose
Revelli
Lewis
Hotchkiss