H6K ‘Mavis’/ H8K ‘Emily’ vs PB4Y-1/2 Liberator/ Privateer – Pacific Theatre 1943-45, Edward M Young

H6K ‘Mavis’/ H8K ‘Emily’ vs PB4Y-1/2 Liberator/ Privateer – Pacific Theatre 1943-45, Edward M Young

This book covers a rather unusual topic – the relatively small number of direct clashes between Japanese and American four engined aircraft over the Pacific. During these clashes the Americans shot down fifteen of the big Japanese flying boats without losing a single PB4Y, a remarkable record.

We start with a look at the development of the Japanese aircraft, tracing Kawanishi’s experience of building flying boats from its first aircraft to the H6K and later H8K. For the Liberator we start with a look at the US Navy’s struggles to actually get any of the aircraft, which involved winning over the USAAF to the idea of the Navy operating land based aircraft, then look at the development of the dedicated Navy versions of the aircraft. This saw an unusually large degree of divergence from the standard B-24, with the PB4Y-2 getting a longer fuselage and totally different tail.

The contrast between the two training schemes is interesting. On the US side the war saw a massive expansion of training, but quality remained high. The section on gunnery training shows that the US Navy took this very seriously, with intensive training in deflection shooting. On the Japanese side pre-war training was excellent, taking twelve months to complete, but it produced a relatively small number of extremely well training pilots. However during the Pacific War the Japanese lost large numbers of these experienced pre-war men, and the IJN didn’t expand its training scheme until 1943. However at the same time training was accelerated, so the quality of new pilots was dramatically lower, with many not capable of operating at night.

It isn’t terribly surprising that the PB4Y performed well against the H6K – it was much more heavily armed and much better protected than the older of the two Japanese flying boats. Its performance against the H8K is some surprising – the Emily was at least as well armed as the PB4Y-2, with five 20mm cannon and five 7.7mm machine guns compared to twelve 0.5in guns on the PB4Y-2, and also had self sealing fuel tanks and some armour. However the Americans shot down five H6Ks and ten H8Ks. In contrast no PB4Ys are known to have been shot down by the Japanese flying boats, although there are cases where the causes of a loss are still unknown, some of which might have involved H6Ks or H8Ks.

The small number of clashes involved means that the author is able to look at every single one of them in some detail. Most of the battles were chance encounters between rival reconnaissance aircraft, although there was one example where the American aircraft was protected a damaged submarine and another where the Americans were sent in a succesful attempt to try and shoot down an Emily that was believed to be carrying Admiral Vice Admiral Yamagata back to Japan to take up a post as Vice Minister of the Navy. 

Looking in detail some patterns do emerge. First, the book only looks at clashes which ended with the Japanese aircraft shot down. Presumably there must have been some in which the Japanese aircraft escaped. Second, some are with unarmed transports, so the American victories here are not surprising. Third, the Japanese amost always seem to have been unagressive and attempted to escape, giving control of the fight to the Americans. Fourth, the Americans made good use of the multiple turrets on their aircraft to maximise the amount of gunfire they were able to direct at the Japanese aircraft. Fifth, Japanese aerial gunnery appears to have been rather inaccurate – in several of the clashes discussed here the Japanese were able to fire at the Americans for some time, but with very few hits.

This is an interesting examination of one of the more unusual aerial clashes of the Second World War, and one of the few where we can be reasonably sure that all fifteen of the claimed victories were indeed real! The aircraft involved and the training of their crews are examined in some detail, and there is a convincing effort to explain why the H8K Emily did so badly. 

Design and Development
Technical Specifications
The Strategic Situation
The Combatants
Statistics and Analysis

Author: Edward M Young
Edition: Paperback
Pages: 80
Publisher: Osprey
Year: 2023

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