The de Havilland Sea Mosquito

The de Havilland Mosquito was undoubtedly one of the Second World War’s most famous and prestigious aircraft, achieving fame alongside models like the Lancaster, Spitfire and Hurricane.

During recent conversations I’ve had with friends, I was intrigued to know more about the different variants, and in particular, the Sea Mosquito – one I had very little knowledge of.

Built in a hangar (disguised as a barn) on the estate of Salisbury Hall near Hatfield, the Mosquito, or  ‘Mossie‘, was a unique aircraft of wooden construction. This design feature eventually gave birth to its nickname the ‘Wooden Wonder‘.

Taking its first flight on November 20th 1940, prototype E0234 (later designated W4050 by the Air Ministry), flew with Pilot Geoffrey de Havilland Jnr at the controls. Its potential as a military aircraft was quickly realised, especially by those who were in opposition of the original idea, and further development trials were organised.


Prototype E0234 (later designated W4050) under restoration at the de Havilland Museum.

The Mosquito went on through various design modifications and variants (41 in all), including fighter-bomber, reconnaissance, target tug and trainer. It also served with numerous air forces across the world, some as far afield as China and Israel. Postwar it obtained notoriety as a film star, the most famous being ‘633 Squadron‘ in which a squadron of ‘Mossies’ attacked the V2 fuel production plant in Norway by bombing an overhanging rock. Film stars such as Cliff Robertson, David McCallum and Gregory Peck have all graced our screens alongside the Mosquito.

With the sad crash of G-ASKH on July 21st 1996 and the death of both pilot and co-pilot, there is no longer a Mosquito flying in the U.K. On September 27th 2012, Mosquito KA114, restored in New Zealand, took to the skies for the first time making it the only flying example in existence at that time.

Plans to build a U.K. flying example are afoot with ‘The People’s Mosquito’ who are raising money as we speak. It is hoped to get the aircraft built and operational, within a few years.

Undoubtedly a success, the Mosquito was a devastatingly potent aircraft, its speed and agility unmatched by most other aircraft of its time. It is a beautiful aircraft and one that was loved not only by those who made, flew and worked with it, but those who, like me, stood in awe and watched it fly. The sound of its two Merlin engines something to behold.

The Mosquito was a great success in a number of operational configurations, and in different theatres, however, one of the lesser well-known variants, and less successful, was the Sea Mosquito.

Impressed with the performance of the aircraft, the Admiralty showed an interest in obtaining a carrier-based version. The de Havilland Aircraft Company put forward the idea of a redesigned model based on the FB.VI – the concept was soon accepted. Trials began soon after in which Mosquito LR359 was adapted, the body strengthened to take the strain of arrester hook landings; its weight was reduced and the Merlin power plants improved.  These tests proved successful, and the first carrier landing completed in late March 1944 by Lt Cdr Eric ‘Winkle’ Brown onboard HMS Indefatigable.

This was a major achievement in many ways, not only for the Navy, but it was the first time any twin-engined aircraft had landed on a sea-based carrier. Further tests followed, and a second Mosquito, also adapted for naval use, joined LR359 in trials onboard naval carriers.

The scene had been set and the Admiralty put forward a specification for a full production naval version, which de Havilland would designate the TR.33.

As with all naval carriers, space was of a premium and so the new version had wing modifications that allowed them to fold. A new and improved landing gear was also needed for the heavy landings that a carrier-based aircraft would be subjected to. Radar was also installed with later adaptations giving the aircraft an odd ‘thimble-shaped’ nose. In addition, attachments for torpedoes were added to the belly of the aircraft giving it greater anti-shipping capabilities.

The first production model, TW227, left the factory in late 1945, but orders came through too late to meet the Japanese threat. Of the initial 100 ordered, only 50 were ever completed. Further trials were undertaken, and the TR.33 would be modified to form the TR.37. This had armament modifications and an upgraded radar system. Again, as with the TR.33, only a few ever made it out of the factory, with only 6 of the original order being completed.

Mosquitoes, whilst being outstanding aircraft, only ever made it to one frontline naval service, 811 squadron of the Fleet Air Arm. Most that were produced were operated from land-based stations and were involved in various trials around munitions development and investigations into naval capabilities. Of those that were made, many of them, in particular the TR.33s, were modified back to regular models and sold off to other air forces, notably the Israeli Air Force.

No further seaworthy variants were made and production concentrated on the land-based models.

The hangar used to build the Mosquito is now the home of the de Havilland Aircraft Museum, (previously the Mosquito Museum) and its main exhibits include, amongst others, the original prototype  Mosquito (W4050) under restoration. Dedicated to de Havilland aircraft, it has a range of models showcasing de Havilland aircraft production from its early days of the 1920s right up to the later modern production fighters and airliners of the 1960s.

Their website can be found here. I visited them a while ago, and my trail can be found here.

More details on 633 squadron can be found on Wikipedia using this link.

A list of locations used in the film can be found here (Thanks to A. Gray for the link).

Details of Lt Cdr Eric Brown and his achievements can be found through this link.

The People’s Mosquito can be found on WordPress or through ‘Aviation Trails‘, alternatively on Facebook and Twitter (@peoplesmosquito).

A remarkable and detailed book illustrating the development of the Mosquito can be purchased from the de Havilland shop. It gives some amazing photos and development history of the aircraft from its conception to cessation of production, detailing production models, uses and variants; it is a worthy book to anyone’s collection.

de Havilland Mosquito – An Illustrated History Vol 2, Ian Thirsk, Crecy Publishing, 2006.



9 thoughts on “The de Havilland Sea Mosquito

  1. It would perhaps be of interest for you to dig out Winkle Brown’s own story behind the first sea trials. The main issue was that the maximum landing speed for the arrester system for an aircraft of the Mossie’s weight was below the stall speed of a Mossie with full flap!

    Liked by 1 person

  2. Thank you for this well-written piece; most enjoyable. You may be interested to know that a photograph of the prototype Sea Mosquito, and Captain Eric ‘Winkle’ Brown, features as one of the images used on ‘The People’s Mosquito 2017 Calendar’ (obtainable from . Sadly, TPM lost a wonderful Patron with the death of Winkle Brown. Ross Sharp, Director of Engineering, The People’s Mosquito

    Liked by 1 person

    • Thank you for the kind comment Ross. Eric ‘Winkle’ Brown was a remarkable man and his death was indeed a great loss for both aviation as a whole and indeed TPM. Thanks for the link I shall take a look as I hope others do too.


  3. The Mossie was indeed a war-winning aircraft. So fast no German plane could catch it until the arrival of jet fighters. The real WW2 conundrum was the wisdom of the decision in 1942 to go for mass production of the Lancaster bomber rather than mass production of the Mosquito. Right or wrong?

    Precision bombing, even in daylight, of German factories, would have been more efficient – and much less costly in RAF crew lives – had the Mossie been chosen – yet the biggest ‘jobs’, destruction of battleship Tirpitz, area targets such as the city of Hamburg – would not have been possible without the Lancaster.
    On the other hand the total of 55,000 air crew lost during WW2 in Bomber Command would have been much lower than the two-man crew of the Mosquito been in action rather than 7-8 crew typically lost on board a downed Lancaster. The Mosquito had the lowest loss rate of any aircraft type.
    Today we now realise that the RAF Bomber Command’s contribution to victory was far greater than nearly all historians, and official histories, realised. Why? It forced the Germans to move more than 8,000 of the crucial, deadly 88m tank-killer guns from the Eastern Front, leaving only 1,500 there to face the might of the Russians. This enormous diversion of arms could not have been achieved by merely attacking factories – only area bombing forced it – and the diversion of more than 1m workers to defend the cities, man the guns, clear the rubble.
    in total, around 665 Tiger tanks were not produced due to shortages and delays caused by RAF bombing – only 1,500 Tigers were ever manufactured. Only 110 Tigers took part in the Kursk campaign. Imagine if the Germans had had another 500-plus Tigers available – the outcome would have been different.
    Tiger tanks and 88mm guns had a kill rate of one round in three, or even two, such as the power and precision of the optics on the weapons. By contrast, thousands of rounds needed to be fired before one lucky projectile brought down a single RAF bomber.
    In addition, area bombing triggered the huge effort put by the Germans into the ‘revenge’ weapons, V1-V3 rockets and guns. These all proved to be militarily worthless yet a huge consumer of German resources. The V1/V2 programme was by far the biggest research project in Europe.
    Next, nearly all fighter aircraft were withdrawn from the Russian front to tackle the Allied bomber streams, often with great effect. However, this move left the German forces in the East with zero air cover. The Germans were unable to undertake the vital aerial reconnaissance over the central front in 1944, and missed the gigantic build-up of Russian forces for Operation Bagration, the largest single attack of WW2 and one which destroyed a large proportion of Germany’s remaining land forces.
    Furthermore, the destruction of the German air force in the aerial battles against RAF and USAF bombers meant that very few German aircraft were available to assault the Allied land forces before, during and long after D-Day. Aerial attacks could have easily destroyed our land campaign.
    On the ‘morality’ balance sheet the bombing of civilians has often been criticised. Yet today the number of civilians killed in the Dresden attack is now known to be around 10,000 – far less than ‘250,000’ oft quoted. Why did we bomb Dresden? It was a vital, hitherto untouched rail link for supplies going to the Eastern Front. The Russians also asked us to bomb it. Should we have refused because of its ‘cultural value’ when the Germans had deliberately destroyed hundreds of cities, towns and villages in eastern Europe and Russia? The Dresden authorities never allowed forced labour workers in factories to stop and enter air raid shelters.

    Lastly, and most important of all, Albert Speer states that the RAF bombing campaign forced one other vastly undermining effect on the German war regime – the production, delivery and storage of vast quantities of ammunition in and around dozens of German cities – which would have been critical in stabilising and defeating Russian land forces – had it been available. German divisional war diaries, even in early 1943, bemoan the chronic lack of ammunition on the Eastern Front.

    My uncle was a navigator on Mosquitoes.. So next time you hear anyone, an ignorant history teacher in our schools, over-active Dresden sympathisers, etc, decry the contribution of Bomber Command – please utilise the above ‘ammunition’.

    Marcus Gibson, ex-FT tech correspondent, London.

    Liked by 1 person

    • Thank you Marcus for adding substantial weight to the argument. The Debate around targets such as Dresden will no doubt go on for eternity and there will be those argue for and those who argue against. The Mosquito was undervalued, certainly initially and was almost never even made. Would it be better to use it than the mass formations of heavies? That’s a big question and with hindsight you are probably right. At the time, I guess, mass formations of heavy bombers were not only seen as more capable of blanket bombing and therefore wide spread destruction, but the resultant damage to morale was probably considered just as important. Whether the tactics worked or not is not for me to judge, but certainly the effects were as you point out, wide ranging and far reaching, even to the point of diverting resources from the eastern front. You raise a number of very valid points, and I thank you for your contribution. It is much appreciated. I shall certainly use it, when the need requires! Andy


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