No 25 Sqn first four AI Blenheim serial nos ?

[andy bird]

Could anyone tell the first four Blenheim serial nos. that came onto 25 Sqn ready to have AI radar fitted.

Many thanks

Andy B.

[bearoutwest]

Hi Andy,

Just reading through the book "Hawks Rising", the history of 25 Sqn RAF. Interestingly, there is very little direct mention in the text of radar equipping the Blenheim Mk If's (though there are a number of references to radars and radar operators in the crew and aircraft lists, kill claims list, etc). The bulk of the text discusses that it was a group of Mk IVf's which were purpose supplied for the initial radar trials.

Radar mentions wrt Blenheim Mk.If :

L6679 RZ-L
Delivered new to squadron, 31st May 1939, later ZK-L. Iced up in cloud, broke up during dive and crashed at Ingatestone, Essex, 16th November 1940. Sgt L T Winter, pilot, Sgt A J Theasby, radio operator (?? possible error - for radar operator) and Sgt A L Romanis, W.Op/Air Gunner, all killed.


Radar mentions wrt Blenheim Mk.IVf :

About a month before the outbreak of war No.25 (Fighter) Squadron took delivery of a small number of Bristol-built Blenheim Mark lVFs, these aircraft forming a special Flight, based at Northolt and North Weald and operating forward from Martlesham Heath. The aircraft were equipped with rudimentary airborne radar. variously referred to as A.I., Mark I, or possibly a bread-board* version of A.I., Mark lll. These were the first aircraft in the world to be equipped with airborne interception radar, and at least three of the Squadron’s pilots who were involved in the trials with thew aircraft were later posted to the Fighter Interception Unit which took over the aircraft and trials in November 1939. Because of the high security classification attached to these trials. it has not yet proved possible to identity with any certainty the aircraft; the following five Blenheim lVFs appear to have been the only examples recorded as serving with No 25 Squadron.

L4906
Aircraft taken over from R.A.E 14th July 1940 (may have been flown by No.25 Squadron while on R.A E. charge). Overshot on landing at Hendon and hit gun emplacement, 21st September 1940, written off. Flt Lt J F R Jones, gunner, injured.

N6193
Previously flown by No.107 Sqn, as bomber but delivered to No.25 Squadron 30th Aug 1939 as a Mk IVF.

N6194
Previously flown by No.107 Sqn, as bomber but delivered to No.25 Squadron 30th Aug 1939 as a Mk IVF. Disposed of to No.248 Sqn 18th February 1940 as standard Mark IVF. (Almost certainly equipped with A.I. radar while with No.25 Squadron.)

N6233
Delivered new to No.25 Squadron 30th August 1939. Taken on charge by A & AEE at Martlesham Heath in September, but returned to No.25 Squadron later that month and remained with the Squadron until 9th March 1940 when it was disposed of to No.248 Squadron. (Probably equipped with A.I. radar while with No.25 Squadron.)

N6239
Received from No.110 Sqn 30th August 1939, with only 4 hours previously flown; disposed of to No.248 Squadron 2nd February 1940. (Probably equipped with A.l. Mk.lll radar while with No.No.25 Squadron.)


Victory claims

He111H (destroyed) 14-Sep-1940; by Blenheim If crew listed as:
P/O MJ Herrick (NZ) (pilot)
P/O AW Brown (gunner)
Air Gunner Frank Files (radar operator)

- the three previous kills had been scored by two man crews in Blenheim Ifs

There is a photo on page 94 of Blenheim Mk.IVf N6239/ WR-L, with what appears to the the radar dipole receiver still visible under the leading edge of the left wing. The arrow transmitter and the corresponding dipole receiver under the right wing have been removed by censor.

On page 99, the text refers to the last month the squadron operated from North Weald (October 1940), when 8 of it's Blenheims were exchanged for aircraft with AI Mk III and two with AI Mk IV. (I assume these were Blenheim Mk If's.) The paragraph then continues with "... Beaufighters arrived at a rate of one or two each week, all fitted with AI Mk. IV, ....".

Regards,
...geoff


[*bread board refers to the open plank installation of the experimental AI sets, so that the operator/boffin could more easily make repairs and adjustments to the electrics/electronics in flight.]

[Alex Smart]

From the ORB, the first aircraft received into the Squadron was a Tiger Moth, the first Blenheim received into the Squadron was Z9318.

[bearoutwest]

Hello Alex,

Not sure which serial you're referring to as a Tiger Moth, but a quick check of Robertson's "British Military Aircraft Serials" (mine's a 1966 edition), indicates:

L6679 - from batch of 250 Bristol 142M Blenheim I built by A.V.Roe

L4906 - mixed batch of Bristol 142M/L Blenheim I/IV, L4823-L4906 being built as Mk IVs.

Z9318 - batch of 250 A.W.38 Whitleys being from a group of Mk Vs (9274-9323)

When the ORB calls Z9318 the first Blenheim, is that the first Blenheim received in-squadron, or the first Blenheim received for equipping with radar?


Confused(?),
...geoff

[Alex Smart]

Hello Geoff,
I have edited my post. So hope my comments are clearer now.
Alex

[bearoutwest]

Hello All,


Just to clarify - I have "no dog in this fight", and no personal reputation involved; so am happy to present scraps of data as available. I am just as happy for others to disagree or to make their own conclusions to share.


Back to scraps of radar-Blenheim bits.
Rawlings' "Fighter Squadrons of the RAF & their Aircraft", has this to add to 25 Sqn:
Mk.If serials in use between Dec 1938 to Jan 1943
K7058 RX-K
L1434 RX-M
L6679 RX-L

K7142 ZK-T
L1200 ZK-H
L1257 ZK-I
L1406 ZK-E
L1408 ZK-J
L1433 ZK-R
L1437 ZK-P
L6676 ZK-A

There is a photograph of L1257 (ZK-I) in which the caption states: "Standing at dispersal at North Weald in February, 1940, is L1257, one of No. 25 Squadron's Blenheim If's with which it was involved in Radar trials at the time."
No serial is visible in the print, only ZK-I. It's a rear starboard quarter view, and no underwing radar aerials are visible and the nose is obscured, so not possible to see the arrow transmitter aerial (also possible that they've been eliminated by the censor). The caption also doesn't indicate what role L1257 might have been used in the trials - possibly even as a target for the radar-equipped intercept aircraft.

Warner's "The Bristol Blenheim - A Complete History" (great book, though a little difficult to quickly find references in) notes:
(p.158-159)
Radar
- doesn't say which squadron, but perhaps just 'D" Flight of Bawdsey Manor Establishment, operating at Martlesham Heath, K7033, K7034 and K7044, were first aircraft to carry primitive AI air-to-air radar sets.
- other aircraft involved in "radar development and calibration and AI trials" included L1113, L4931, L4932, L6595, L6622 and L1201.

(p.164-165, quoted verbatim)
Night-fighter Blenheims
In November 1938 Mk I L6622 was based with the A&AEE at Martlesham Heath to work with Bawdsey on air-to-air radar, being joined by L6627 in March 1939. L6622 went to the RAE at Farnborough to join L6624 there, and was then sent back to the A&AEE on 2 January 1940. L6623, L6625 and L6626 had been engaged on similar radar development work. The fruit of their research was a top secret but world-leading order, issued on 17 July 1939, for 21 Blenheim Mk I-Fs to be equipped with Mk III AI sets at RAE Farnborough, and the first, L1290, was delivered to 25 Squadron on the 31st, and 15 aircraft with the new device were in service by the outbreak of war. By November 1939 604 Squadron had L6802 and L6807, while 600 Squadron had three AI-equipped I-Fs (L1494, L4906 and L8669), which were detached to a special flight at RAF Manston in a futile attempt to catch the Heinkel He.115s that were mining the Thames Estuary by night - no successful interceptions were made as the ground returns on the elementary AI radar obscured the ‘blips’ of the low-level raiders. This flight, under S/Ldr (later Air Marshal) Walter Pretty, who had commanded one of the early Chain Home Low radar stations, was developed into the Fighter Interception Unit at Tangmere. AI sets were installed in the ten Mk I-Fs serving with the FIU, whose aircraft (L1186, L6651/88, 6720/88, 6805/35/36/37/38) were used for extensive trials - and operationally whenever possible - to develop radar-assisted interception methods. The FIU moved to Ford and, as we will see, achieved an historic first when F/O G. Ashfield in L6836 made the first ever successful radar-guided night interception using Mk IV AI and shot down a Dornier Do.17Z on the night of 22/23 July 1940. Sixteen brand-new Blenheim Mk IV-Fs (P4829-37 and P4844-50) were delivered straight from Bristol to the RAE at Farnbnrough during September and October I939 for AI sets to be fitted before issue to the Special Duty Flight and the night-fighter squadrons over the winter.

A flight of 25 Squadron was detached from Northolt to Martlesham Heath in November 1939 to re-equip with Mk IV-Fs from that batch, fitted with Mk III AI, and cumrnenced North Sea patrols at night, but there was a lack of ‘trade’ for them. 604 Squadron received P4847, its first Mk IV-F fitted with AI, in December 1939, just before it moved to Marllesham Heath for intensive Al trials and training. Other Mk IV-Fs from that special radar-equipped batch were P4830/32/34/48 for the Special Duty Flight; P4829/37/46 for 600 Squadron; P4833/35/45 for 29 Squadron; P4836/44 for 23 Squadron; and P4849/50 for 64 Squadron.

(extracts from p.239, quoted verbatim)
Two more Mk I-Fs were lost on 31 July when L1408 of 25 Squadron and L6722 of 29 Squadron collided over the Bristol Channel while carrying out tests with their new Al radar sets; all aboard both aircraft were killed... .

...The first practical version of Al was the Mk IV, an improvement over the earlier experimental marks, and the first to be rushed into full production — only 25 of the bulky and very temperamental earlier Mk lll sets had been ordered just before the outbreak of war. The FIU operated ten Mk l-Fs with AI radar - L1186, L1340, L1404, L6688, L6788, L6805, L6835, L6836 (which scored the historic ‘first'), L6837 and L6838. The Radar Developnlent & Training Flight at Martlesham Heath operated L6622, L6624 and L6627.


...geoff

[bearoutwest]

So my conclusions from putting together the above bits from a number of posts:


A&AEE Martlesham Heath (working with with Bawdsey on air-to-air radar)
(radar-equipped)
K7033
K7034
K7044
(radar development and calibration and AI trials)
L1113
L4931
L4932
L6595
L6622 (Nov 1938)(then to RAE at Farnborough)(back to A&AEE 2 Jan 1940)
L1201
L6627 (March 1939).

RAE at Farnborough
L6623
L6624
L6625
L6626

17 July 1939, 21 Blenheim Mk I-Fs to be equipped with Mk III AI sets at RAE Farnborough
L1290 (25 Sqn - 31 July 1939)
L1408 (25 Sqn - lost in collision with 29 Sqn, not sure if AI MkIII or IV)

L6722 (29 Sqn - lost in collision with 25 Sqn, not sure if AI MkIII or IV)

L6802 (604 Sqn - Nov 1939)
L6807 (604 Sqn - Nov 1939),



600 Squadron had three
L1494 (600 Sqn - Nov 1939)
L4906 (600 Sqn - Nov 1939)
L8669 (600 Sqn - Nov 1939)

L1186 (FIU - Nov 1939)
L6651 (FIU - Nov 1939)
L6688 (FIU - Nov 1939)
L6720 (FIU - Nov 1939)
L6788 (FIU - Nov 1939)
L6805 (FIU - Nov 1939)
L6835 (FIU - Nov 1939)
L6836 (FIU - Nov 1939) - claimed 1st AI-guided kill F/O Ashfield
L6837 (FIU - Nov 1939)
L6838 (FIU - Nov 1939)

16 brand-new Blenheim Mk IV-Fs (P4829-37 and P4844-50) were delivered straight from Bristol to the RAE at Farnbnrough during September and October I939 for AI sets to be fitted before issue to the Special Duty Flight and the night-fighter squadrons over the winter.

Special Duty Flight - P4830/32/34/48 (4-off)

600 Squadron - P4829/37/46 (3-off)

29 Squadron - P4833/35/45 (3-off)

23 Squadron - P4836/44 (2-off)

64 Squadron - P4849/50 (2-off)
(Rawlings: P4850 Mk IVF, before Spitfires arrived Apr 1940)

Process of elimination leaves these serials that might have also been used for 25 Squadron:
P4831
P4847 (to 604 Sqn, Dec 1940)

In addition to original list of Mk.IVf's from "Hawks Rising":
L4906
N6193
N6194
N6233
N6239 WR-L


...geoff

[andy bird]

Wow . . . Thank you.

Andy