de Havilland Mosquito NF Mk XIII

Mosquito Night Fighter XIII MM558, ME-E (Nicknamed “The Mighty ‘E’ the Second”) was to become Broody & Jack’s regular aircraft, replacing their Mk XII aircraft, HK227. She was built at Leavesden as one of a batch of 126 aircraft ordered for delivery between January and May 1944.

Much has been written about the de Havilland Mosquito, and I would never be able to do the marque full justice in this post – rather I will give an overview of the Mk XIII.

© IWM (CH 14643) A Mosquito NF Mark XIII (HK382) of 29 Squadron RAF.

The MK XIIs previously used by the squadron were essentially MK II Night Fighters converted to house the Mk VIII Airbourne Interception radar. The next generation  Mk XIIIs were the factory-built (ie not converted) variant, based on the FB VI (Basic) and fitted with Merlin 21, 23 or 25 engines (MM558 was fitted with Merlin 25s). Her wooden construction meant that good quality aircraft could still be built despite the shortage of metals, and made use of the nations’s carpenters and joiners in the war effort.

To accommodate the radar in the nose of the aircraft, the 4 Browning .303 machine guns were removed. The only remaining weaponry were the 4 20mm Hispano cannons fitted in the belly of the fuselage. At any rate, one of the main forms of defence for the mosquito, and in fact her raison d’être was her speed – She could outfly any other aircraft, allied or axis.

Maximum speed was stated as 394mph at 13,800 feet, reducing to 379mph at 6,000 feet. The aircraft had a operational ceiling of 28,800 feet, and an initial climb rate of 1,870 feet per minute. At the recommended cruising speed of 220mph at 20,000 feet, she had a still-air range of an amazing 1,260 miles.

© IWM (CH 14646) A Mosquito NF Mark XIII looking along the lower fuselage towards the tail, showing the aircraft’s armament of four forward-firing 20mm Hispano cannon.

I remember on a trip to the RAF Museum in Hendon with my grandfather, he explained how access was through a tight hatch on the starboard side. Once both pilot and navigator were installed in the cockpit, there was not a lot of room for manoeuvre – it was definitely not the place to be if you were claustrophobic!

© IWM (CH 14649) A Mosquito NF Mark XIII. View looking into the cockpit through the starboard entry hatch in the nose.

To illustrate the lack of space in the cockpit, the next photo shows a cockpit of a Mosquito (possibly a NF MK XII) -You can see the main control yoke that would have been between the pilot’s legs to on the port side – in very close proximity to the A/I system on the starboard side.

© IWM (CH 16607) de Havilland Mosquito (NF) cockpit

The A/I radar was, of course, Broody’s main tool in the hunt for enemy aircraft. The following is a description of the system in his own words:

“The aircraft carried A .I. (Air Interception) Mark VIII radar, of the centimetric variety. The radar beam, narrow in itself, scanned a cone ahead of the aircraft 45 degrees from centre line in all directions. This was achieved by a rotating reflector in the nose, which not only rotated about its axis at high speed, but also constantly swung out to 45 degrees and back again. The significant effect of this was that, at the lowest point of scan, the radar beam picked up “ground returns” – reflections from the ground, or, weaker but still prominent, the sea. Consequently, as the beam scanned out and back again, a green “wash” of light moved up and down at the base of the display unit, which was essentially a basic cathode ray tube. As my function on a defensive patrol was to watch the radar display, the soporific effect was considerable.”

© IWM (CH 16606) Airborne Interception Radar Mark VIIIB indicator and receiver in the operating position, as seen from the observer’s seat of a De Havilland Mosquito NF Mark XIII night fighter. The visor has been removed from the screen on the indicator unit (top). The receiver unit (bottom) was hinged so as to fold back into the space beneath the indicator unit in order to render access and egress from the cockpit via the door at lower right.

© IWM (CH 16610) Airborne Interception Radar Mark VIIIB installed in the nose of a De Havilland Mosquito NF Mark XIII night fighter. The transmitter box is at the top, mounted above the scanner hydraulic motor assembly. The rotating scanner is contained in the perspex nose.

The following animation and a description of the picture you see, reproduced with the permission of its creator, Norman Groom, will hopefully help you to understand the system a little better

A/I Mk.VIII Animation
© Norman Groom

The radar screen is the green circle on the left and the target aircraft simulation appears on the right. The target aircraft at night is invisible to the pilot until the target is within a few hundred yards of the night fighter and the pilot is directed onto the target by information given to him by the radar operator from the information on his radar screen The target echo appears on the radar screen as a yellow arc of a circle. In practice the screen is just one colour (green) but in this animation it has been changed to yellow to make the echo easier to identify. The distance of the arc from the centre of the screen is proportional to the distance that the target is in front of the night fighter. The direction of the echo indicates the direction of the target (up, down, left or right) and the length of the arc tells the operator how far the target is ‘off axis’, When the target is ‘dead on axis’ the target echo becomes a complete circle. The band of noise at the bottom of the radar screen is an echo due to reflection from the ground, below and forward of the aircraft when the beam sweeps downwards. (©Norman Groom)

Two of 488(NZ) Squadron’s NF XIIIs deserve a special mention. You may remember that on 8/xi/43, F/O Graeme Reed and P/O Ralph Bricker claimed the Squadron’s first  ME410 in HK367. This was in fact the first enemy aircraft claimed in a NF XIII by any Squadron – so a double-first for the Train Busters!

The second aircraft of note was MM466. Delivered to 488(NZ) Squadron on 25/ii/44 and passed on to 409 Squadron on 09/xi/44 – she holds the honour of being the Top Scoring Mosquito fighter during the war with a total of 11 enemy aircraft destroyed. 6 of these were while she was with 488 – but the time to tell her story properly will come later! You can see a list of all the de Havilland Mosquitos used by the Squadron here.

If you are interested in reading more about the de Havilland Mosquito, I thoroughly recommend the book “Mosquito” by C.Martin Sharp & Michael J.F.Bowyer. I have an original 1967 edition from Broody’s collection, but a republished and updated version is available on Amazon at the link above. It is a fantastic, meticulously researched and informative book.