Notes
- 1. The M4, M10 and M9
- By a publicity effort the American Aircraft Co. (AAC) managed to
associate itself with the M4 and M10 series of cannon, and
it is sometimes named as its manufacturer. In fact AAC's cannon
was far inferior, and never seems to have been used in combat
by anyone. The M4 was designed by Browning, and production
was undertaken by Colt.
Another source of confusion is that rather frequently, the
performance data for the Oldsmobile-produced M9 are listed
in tables, creating the impression that this was a standard weapon
in US aircraft, or that the performance of the M9 was somehow
representative of that of far less powerful and more common M4
and M10 (for example in Ref. [26]).
I have found no record of any installation of the M9 in production
aircraft, the weapon seems only to have been used in a few
prototypes. There are unproven rumours that it was installed in
some aircraft Lend-Leased to the USSR...
- 2. Oerlikon cannon
- The relatively modest performance of the Oerlikon cannon has
been generalized by many people to the inaccurate conclusion
that all WWII 20mm cannon were slow-firing, low-velocity weapons.
A good example is Ref. 37, in
which R. Mikesh makes a valuable effort to analyze the
Zero's armament, but simply ignores the fact that the Japanese
Navy made a poor choice when it adopted the Type 99-1 and 99-2
Oerlikon derivatives. The locked-breech weapons that replaced
the Oerlikon in most services had considerably superior
performance.
- 3. B-17 losses
- In early 1943, before the distasters of Schweinfurt and
Regensburg, the book "The Air Offensive Against Germany"
by Allan A. Hitchie (Henry Hall & Co, NY, 1943) was
published. The author of this work was obviously influenced
by the RAF, and he gave a very realistic assesment of the
defensive firepower of the B-17s and B-24s, and its
limitations. These defeats did not happen without prior
warning.
- 4. Evolution
- Ref. 35 gives the following
statistic: In the last 6 months of 1942 only 40% of the hits
recorded on B-17 bombers were cannon hits. In the autumn of 1943
this had risen to 80%. In 1944 there were 35% more cannon hits
than machinegun hits.
- 5. Hispano Mk.V
- The British reduced gun stoppages with the Hispano to 1 in 1500
rounds, and the deletion of the in-flight recocking device
illustrates their confidence in the weapon. But in US service
complaints about the reliability of the Hispano, especially its
feed mechanism, were frequent. (e.g. "Great enthusiasm was expressed
over the 20mm cannons in the SB2Cs, even though feed-mechanism
discrepancies occur frequently." Ed Heinemann, by E. Heinemann
and R. Rausa, Naval Institute Press, 1980.) The causes of this
discrepancy are unclear. They may be related to maintenance problems
or to the design of the gun mounts. American-made Hispano cannon
were considered satisfactory by the RAF.
- 6. Serrate
- Serrate was a homing device tuned to the emissions of the
German Lichtenstein SN-2 radar. This allowed the Mosquito to operate
against German nightfighters. There was a reluctance to allow
radar-equipped Mosquitos to operate over Germany, because the
highly advanced radars would almost inevitably fall into German
hands.
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© 1998-1999
Emmanuel Gustin
gustin@uia.ua.ac.be
visitors since 23 December 1998.