This is not to dispel the legend surrounding the Battle of Britain. I have read extensively on this period of British history and have nothing but the utmost respect and admiration for all personnel involved. Rather it is an examination on how those in government, in positions of power and responsibility bathe in the limelight despite the fact that decisions made by them were not always the correct ones. In some ways, the Battle of Britain; a genuine battle for democracy and freedom was won, not because of political decisions, but in spite of them.
Firstly, it must be noted that both the Hawker Hurricane and the Supermarine Spitfire were private enterprises and each company and designer had to fight to have these planes accepted, manufactured and ready for 1940, replacing bi-planes armed with two or four light machine guns within months of the battle.
Is a whirlwind more destructive than a hurricane?
As much as I admire the Spitfire, I retain a deep affection for the Hurricane. A solid plane, good gun platform, easy to fly…dangerous if the engine caught fire. It shot down more enemy aircraft during the battle than any other aircraft, yet it has to be accepted that it was based on bi-plane technology and would always struggle to remain an equal to ever advanced rivals.
In 1935 Westland began work on the Whirlwind to meet Air Ministry Specification F.37/35. It first flew in October 1938 and entered service in 1940 after delays attributed to a lack of Peregrine Rolls Royce engines.
“..four closely grouped heavy cannon in the nose had a rate of fire
of 600lb/minute which, until the introduction of the Beaufighter,
placed it ahead of any other fighter in the world” (Profile series).
The 20mm cannon armed Whirlwind had great speed and rate of climb, excellent manoeuvrability and good all round vision from the cockpit, it was also faster than a Spitfire Mk1 fitted with a three bladed airscrew. The Spitfire and Hurricane were armed with eight .303 rifle calibre machine guns that were often too light to destroy Luftwaffe bombers.
That statistic is even more remarkable when you consider that the Whirlwind was engined with 885hp Peregrines and the Spitfire had the famed Merlin rated, at the time, at 1030hp.
So why wasn’t the Whirlwind powered by Merlins?
There was a general fear that Merlin production would not be sufficient to power the Hurricanes and Spitfires needed for the Battle of Britain. Indeed, tests were being made to fit Hurricanes with Bristol built radial engines. This fear was, largely, proved, unfounded. No doubt, Rolls Royce, run by the level headed Lord Hives, was concentrating on Merlin production and not Peregrine improvements. This lack of Peregrine engines severely slowed Whirlwinds introduction to frontline squadrons. The thought had occurred to someone that the Whirlwind could be re-engined with Merlins but at some stage the Air Ministry and the Ministry of Aircraft Production rejected the idea because they considered “it’s fuselage was too small and it’s entire layout unpromising”. A conclusion that seems misguided. The engines were mounted on the wings and the layout of four grouped cannon in the nose and sighted through the pilot eye-line seems very promising.
It is always difficult to compare aircraft; this is from The Fighting 109.
At 15,000 feet.
ME 109 E-3 338mph
Hurricane Mk1 303mph
Spitfire Mk1A 342mph
Profile magazine gives a normal loaded weight Whirlwind as 304mph at the same height (360mph empty; it is unclear whether the figures in The Fighting 109 are based on a loaded or empty airframe. It is assumed that it is based on their combat weights and speed. It must also be remembered that the Whirlwind speeds are based on the 885hp rated Peregrine).
Which leads us to an interesting conjecture. What if the Whirlwind had been powered by Merlins?
A rough calculation would be that the Merlin Mk I, Mk II engine was around 20% more powerful than a Peregrine. So, taking this we could, at a conservative estimate, postulate that a Merlin powered Whirlwind would have been, at least, 10% faster. Giving it a speed of around 340mph, possibly more. One needs only to look at the improvement of the P51 Mustang when the Allison engine was replaced by the Merlin.
From the pilot’s point of view, he had a plane that was speedier than anything the Luftwaffe had, including their fighter and which packed a lethal punch. There were other advantages: If one engine was shot out, even on fire, there was a good chance he could still land the plane; he had the advantage of fighting over home territory. If a Hurricane’s engine was hit and flaming, the pilot would have to get out, the plane and the Merlin engine lost. So many pilots were also lost or terribly injured in this situation. A Whirlwind, because of its two engines, had a better chance of leaving the fight and landing, saving the pilot and, at least, one if not both engines. An argument that, I think, dismisses any of the concerns about lack of Merlins or unsuitability of the airframe.
In conclusion, the RAF had the opportunity to have a plane similar to the P38 Lockheed Lightning, with much heavier armament, in 1940; those in positions of responsibility chose otherwise.