Bristol Blenheim Mk I

Airfix 1/48 Bristol Blenheim Mk IF (A09186)

Box cover and painting guide

Kit

This Bristol Blenheim Mk IF kit was released in 2018 by Airfix. It was long-awaited amongst Finnish modellers because it could be built out of the box as a Finnish short nose Blenheim Mk I bomber (precisely a Finnish series IV plane). Airfix kit depicts Mk IF nightfighter version which differed from bomber version by having a ventral gun pack. Also part of the night fighters were equipped with radar antennas. The kit is well designed and engineered. Main parts have locating pins and alignment of the parts is mainly good. Wings to fuselage alignment is strong due to two wing spars which also force the angle of the wings right. Control surfaces are separate so they can be depicted at your will. Landing flaps can be depicted retracted or down position.

The kit is moulded in light bluegrey styrene and consist of 196 parts of which 16 are clear parts. Not all parts are to be used. Styrene quality is typical for Airfix and it is softer than many other manufacturers have. Detailing is mainly engraved panel lines. Raised rivet stubs and lap joints are depicted with raised patterns. Panel lines on fuselage are broader than on wings. Longitudinal panel lines at the bottom of the fuselage are missing and some traverse lines are in wrong places. Fabric covered control surfaces looks good although there are some sinkholes on them. All in all detailing level seems to be quite good. On the other hand there are sinkholes here and there for example on both sides of the fuselage (under the canopy glazing), on wing root fairings at trailing edges, under the rear fuselage, on ailerons and on upper surfaces of the wings (trailing edges).

Cockpit is quite good if made out of the box. There are also good PE sheets on the market if you want to make some improvements to the cockpit. Eduard has made good instrument panel and pilots harnesses which are are worth to acquire because they can be seen well through the big greenhouse canopy. Instrument panel is well visible under the big canopy and it may be a good idea to add some wirings behind it. I also recommend to acquire Eduards painting masks for this project, they just are must! Casting conduits of gun turret (6) are partly fastened to the turrets clear part and they are difficult to cut-away without any traces on the cutting area. Some polishing work to remove those cut-away marks from turrets lower edge are necessary. An intreresting and useful accessory to assemble the mg-turret is a little jig which come with the kit.

Landing gears and wheel wells are well detailed including for example oil tanks in the wheel wells. Engines are quite good although brace struts between gearbox and exhaust collector rings are missing. V-shaped brace struts are missing six/engine. The brace struts are quite visible and its well worth to add them to the model. The kit includes two separate cooling gills, one in open and one in closed position. When building a Finnish Blenheim Mk. I (IV series) don't add part number C22 but instead fill it's fixing hole. Slot at cooling gills for part C22 have to fill with styrene sheet (picture below). The kit includes also separate cooling gills for the left engine (in open and closed position) which have a notch for aerial radar antenna used in the night fighters.

Plane's glass nose is devided to left and right halfs and one upper front section. There is also a glass hatch to the top of the fuselage. The part number to be used in a Finnish Blenheim Mk. I (series IV) plane is G4. The undermost panel of the part is not made clear but it is easy to polish. Narrow elongated window at the left side of the cockpit didn't have a vertical strut which have to sand away. Clear hatch on the top of the fuselage didn't have a traverse strut on it so it have to sand away. So there is some sanding and polishing work coming for you.
(Take a look at work in progres pictures below).
The kit includes also an optional clear part to the left side of the cockpit but it is not suitable for a Finnish IV series plane.

The kit contain decals and painting guides for two British planes. One totally black and one in normal British bomber scheme. Finnish Mk. I (IV series) planes had the British bomber scheme where colors were Dark Green, Dark Earth and Night (Black). Part of the Finnish Mk. I (IV series) planes were put together with parts from two planes. BL-134 had fuselage and rudders painted in British A-scheme while wings were painted in B-scheme. Also BL-139 had it's fuselage and rudders painted in A-scheme but wings painting scheme is not familiar to me. A- and B-schemes were mirror schemes of each others while colors were same.

At some pictures taken during the Winter war can be seen bomb racks for small bombs under the rear fuselage. Probably the racks were used in all IV:th series Mk. I planes of the LLv 42. Probably they were never used during the Winter war and they were removed from the planes during the war or as soon as the Winter war ended. The kit includes these bomb racks fitted with bombs. During the Winter war at least part of the LLv 42 series IV planes had tail skids.

I retained the foremost observers seat on my model because I saw a photo which was taken in July 1941 where the seat still was in its place of a LLv 42's Blenheim Mk. I. The seats were often removed as unnecessary.

Some sources mention a curtain between cockpit and middle fuselage of the Finnish planes. According to documents found by researchers of a Finnish Flightforum the curtains were used only on series VI (BL-196 - BL-205) planes and at one plane on series I (BL-117). No data that the curtains were used on other series or planes is not found.

Building the model

I started by washing sprues in Fairy water as stated in Airfix's instruction booklet. Reason for this is to remove mould silicon from the parts to improve paint adhesion. After I had cutted off the fuselage parts from the sprues I puttyed and sanded off ejector marks from inside of the fuselage. I then cutted off all the parts that comes inside the fuselage and prepared them for painting. At this stage I added lacking armour plate made from a thin styrene sheet behind the pilot's head. The armour plate should be installed tilted a bit backwards. At the lower edge of the armour plate there should also be an oval aperature (take a look at "work in progres" photos below). The color of the armour plates looks to be the same as the cockpits interior color that is "Interior Grey Green".

Cockpit is quite complicated with plenty of small parts. It needs test fittings to complete it right. I screwed up when I glued part D11 about 0,5 mm too high. I noticed my mistake when I glued rudder pedals to their places. Pedals stayed awry and they had to disengage. After I had repaired the fixing point I glued the pedals at this time to their correct position. I also had to lower the upper side of the part D11 to make part D1 fit properly inside the canopy. A lot of additional work due to a small mistake. Backside of instrument panel is open and visible when the model is completed so I added some wirings there. I used various PE parts from Eduard on my model of which the most visible are instrument panel and pilot's harness.

Engines are quite good with few corrections. Finnish Blenheim Mk. I (IV series) did not have air ducts on engine nacelle (part C22). Correction for this is to fill part's C22 fixing hole. A slot at the cooling gills have to fill with styrene sheet and reshape (picture below). Brace struts between gearbox and exhaust collector ring have to add (6/engine). Reference pictures can be found with internet query "Bristol Mercury VIII". I made the brace struts out of thin brass rod and glued them to their places with CA glue. Fitting of engine cowling parts wasn't good and there were left some slots between the parts. I had to fill them with putty, sand and rescribe all the panel lines. This was slow and time consuming stage. At the end I painted the the engines with camouflage colors before gluing them to the wings.

I glued clear parts to their fuselage halfs before glueing fuselage together. When the fuselage was put together I fixed a joint between fuselage and lower edge of canopy with putty. I also sanded the lowest frame of the canopy a bit shallower. I puttyed all too broad panel lines on the fuselage and re-scriped them. To the bottom of the fuselage I scriped all the missing panel lines.

Wing panel lines are narrower than those of the fuselage and they are good as such. I built my model's landing flaps in closed position and had to remove some structures inside of the flaps as instructions tells. Landing gears have to build and painted ready before they are glued to lower wing halfs. Although the landing gear is quite sturdy it bears a problem as it impedes working with the wings. From the rudders front edge a surplus hinge opening has to be deleted. Kits antenna mast lenght is right if it is pushed through a hole on the fuselage straight to a hole at the part A27, the mast should be exposed 21 mm.

Faults and shortcomings that I corrected on my model, "work in progres" photos can be found farther down.

- An armour plate is added to the top of the pilots seat.
- On underside of the nose glazing one opaque panel is sanded and polished.
- A vertical bar has to be removed from a narrow window at the left side of the nose.
- A traverse bar has to be removed from a transperant hatch at top of the fuselage.
- Oil coolers air ducts (part C22) were not used in Finnish planes, their slots are filled at the cooling gills.
- Brace struts are added to the engine between the gearbox and exhaust collector ring.
- Too wide panel lines on the fuselage are filled with putty and new narrower are scribed.
- Missing panel lines are scriped to the bottom of the fuselage.
- From the rudders front edge a surplus hinge opening is deleted.
- Pitot-tube is corrected.
- Faulty panels above the engine cowlings are corrected.

Extra parts used on the model:

CMK: Flattened main wheels with rims and air ducts.
GasPatch: Vickers K machine gun for tail gunner.
Eduard: PE parts to cockpit e.g. instrument panel and pilots harness.
Eduard: Paint masks for clear parts, include masks for inside and outside.

Paintings and markings

My model depicts a Finnish AF plane BL-143 in the summer of 1940 at Luonetjärvi AB. The plane had RAF B-camouflage scheme with Dark Green/ Dark Earth/ Night (Black) colors. SBS-models painting instructions differed from the B-scheme on nose. I painted left side of the nose green according to the B-scheme. The plane had big Finnish national markings and register markings were British style fonts. On a photo of pilot's manual and photos from other sources taken inside the cockpit the canopy frames were painted in black. I painted my models canopy framings black from the inside as well as the inside framings of the dorsal turret. Interior color of the fuselage and the cockpit is RAF Grey Green. Airfix suggest Silver to the wheel wells but I can't tell is it right. Talkings on the Britmodeller.com Forum keeps it more likely that the right color is rather Grey Green which I also used on my model.

Paints used on the model are Humbrols HU116 "Dark Green" and HU29 "Dark Earth" for upper sides. Undersides are painted with XtraColor X12 "Night Black". Interior color, cockpit and wheel wells are painted with Humbrol HU78 RAF Grey Green.

I ordered SBS models decal sheet D48007 for my model of which I used only identification markings for the plane and RAFs squadron emblems to the fin. Diameter of SBS models wing roundel is 40 mm which is 2,5 mm too much. I replaced the wing roundels with roundels from AML Decals 48016 sheet. They had a diameter of 37,5 mm what is just right. Blue color of national insignias of the AML Decals looks darker and more realistic than the color of the SBS decals which is too pale blue. Location of the wing roundels is not right in SBS models instructions. In the book "Blenheim Suomessa" by Igor Kopiloff there are exact measurements for the wing roundels. All small markings are from kits decal sheet. You can also use this Asisbiz.com photo to see the right places of the wing roundels.

Airfix decals were quite thick and didn't react to Micro Sol at all. AML Decal national markings were right sized and right colored. They were also thin and very fragile and reacted strongly with Micro Sol. On two national markings blue color layer detached from white bottom creating bubles between the layers which were difficult to work out. SBS decals worked like a charm and reacted with Micro Sol very well.

Later learned: SBS model have another decal sheet for Finish Blenheims (D48019). On that sheet there are right sized national markings to the wings. So have to say afterwards that I would recommend to use this SBS model sheet instead of AMD Decals.

BL-143 history:

BL-143 was one of those so called "IV-series" twelve planes which were flown from Great Britain to Finland during the Winter War. Planes were flown through Norway and Sweden to Finland by British pilots. The planes had civil register markings during the flight and pilots acted as civil persons because of the orders of the British Air Ministry. The planes were used and they were gathered from several RAF units. Some of the planes may have seen service as a nightfighter. The Blenheims were flown to a frozen lake to Jukajärvi at Juva from where they were used against assaulting Soviet forces at the Bay of Viipuri to the end of the Winter War.

BL-143 arrived to Finland during the Winter War on 26.2.1940 and belonged to 1/LLv 42. On 17.3.1940 left landing gear collapsed during taxiing at Luonetjärvi. On 25.6.1941 belonged to 3/LeLv 42. On 2.10.1941 was shot down by anti-aircraft defense at Mundjärvi west of Kontupohja. Pilot vänrikki E. Joutsen parachuted and came back through the lines. Observer vänrikki J. Ampiala and gunner alik. T. Punnonen were killed. Total flying time 641 h 30 min. On 6.11.1941 was written off. Weared an oak leaf emblem of its previous user RAF 108 Squadron which was left on the fin.

The kit includes decals and painting instructions for two planes:

Blenheim Mk. IF No 23 Sqn, RAF Wittering, Cambridgeshire, England, February 1940 / Dark Green/Dark Earth/Night.
Blenheim Mk. IF No 54 OTU, RAF Church Fenton, North Yorkshire, England, December 1940 / Night.

Paints used:

The first figure which indicates sheen level of a color on FS number is dropped off. Ak=Akan, X=XtraColor, LC=LifeColor, HU=Humbrol, R=Revell, WEM=White Ensign Models, MrH=Mr Hobby Aqueous, Tam=Tamiya. (Alternative paints between brackets).

Dark Green (RAF Dark Green)	FS - 34083	HU116 (X1,MrH H73)	Camouflage top side
Dark Earth (RAF Dark Earth)	FS - 30118	HU29 (X2, MrH H72)	Camouflage top side
Black (RAF Night)	FS - 37038	X12	Camouflage under side
Grey Green (RAF Grey Green)	FS - 34226	HU78	Cockpit and all interiors
Yellow	FS - 33538	MrH H413, (X106)	Tips of propeller blades

Summary

Airfix fullfilled expectations of many Finnish modellers with this kit. There is no big issues on the model and it is reasonable easy to built. Remarkably there are plenty of sinkholes on wings and fuselage even though this is a main stream kit. Most challenging sub-assemblies were cockpit, engines, landing gears and clear parts. When you get these subjects ready rest of the building process is nothing but a joy.

Hold mouse cursor over a thumbnail for a while before clicking

History

The Bristol Blenheim was a British light /medium bomber aircraft used during the Second World War. It was all-metal structure and was designed and built by the Bristol Aeroplane Company (Bristol). Bristols main designer Frank Barnwell designed in 1933 a modern passenger plane, Bristol Type 135. It was aimed to be an answer e.g. to American Douglas DC-1. A British newspaper mogul was interested of the plans and constructed one which was designated type 142 "Britain First". The maiden flight was on 12. of April 1935. The new plane was 70 km/h faster than the fastest RAF fighter Hawker Fyry II, the last of the RAF biplane fighters.

The British Air Ministry was interested of the plane and Bristol made two bomber proposals based on the Type 142. On July 1935 the Air Ministry chose a version fitted with Mercury engines for further developments. After a group of changes to the plane the 142M was born and it was later named Blenheim. On August 1935 RAF ordered 150 Blenheims without ordering any prototype first. The first Blenheim was completed on June 1936 and on July 1936 Bristol got a contract for additional 568 planes. By the end of 1936 1568 Blenheim I's was ordered to the RAF.

The Blenheim Mk. I had a crew of three and a cramped nose interior especially for observer/ bombardier. A specification M.15/35 was made for the RAF Coastal Command which led to the Type 152 better known as the Bristol Beaufort. While Beaufort was in drawing board it was desided in 1936 to make a long nose version of Blenheim which was first named as Bolingbroke. The new plane got more powerfull Mercury engines which used 100 octane fuel and extra fuel tanks which were installed to outer wings. Maiden flight was in September 1937. RAF Coastal Command never got its Bolingbrokes but Hudsons instead. Bolingbroke I was renamed Blenheim Mk. IV and all Blenheim orders were changed to the Blenheim Mk. IV in the summer of 1938.

Blenheim Mk. II and Mk. III were left on drawing board and never materialized. Later version Blenheim Mk. V was named Bisley I. When Blenheim Mk. IV deliveries started to squadrons modifications were made to Blenheim Mk. I to make a night fighter. Blenheim Mk. IF night fighter was created by installing a tub with four machine guns under it's fuselage. Same kind of modifications were later carried out for Blenheim Mk. IV. Fighter versions were used as night fighters during the years 1940 and 1941 until Boulton Paul Defiant and Bristol Beaufighter replased it on night fighter role.

The plane was sold to Finland, Turkey, Yugoslavia, Romania, Greek and Portugal. Finland was the first foreign customer who acquired Blenheims. Yugoslavia and Finland also bougth manufacturing license of the plane.

At the outbreak of the Second World War Blenheim's speed advantage compared to the fighters was gone. The bomber couldn't shake off modern fighters and it's defencive armament was insufficient. Losses were great and in the autumn of 1940 Great-Britain had lost already 234 Blenheims. However Blenheim stayed long in service in the Far-East where it was fast enough to shake off Japan Army Air Force fighters such as Nakajima Ki-27 "Nate" or Nakajima Ki-43 Hayabusa "Oscar". Bomb load and range of the Blenheim was not as good as it was on the heavier Wellington, Hampden and Whitley.

Acquiring Blenheims to Finland

Finland was interesred in Britain First in 1934. At first the bigger Type 143 was the subject of the trade but when RAF ordered Blenheims in 1935 interest was changed to Blenheim. In October 1936 Finland ordered 18 Blenheims. The planes got Finnish bomb racks for 800 kg bomb load (in the fuselage) and half of the planes were equipped with Tampella (Finnish factory) built Mercury engines. First of these planes were completed in July 1937 and the rest not until in 1938.

In April 1938 Finnish Defence Ministry bought manufacturing licence for Blenheim Mk. I from Bristol. 15 Blenheim Mk. I's was ordered from Finnish State Aircraft Factory. Starting of the production took much time because of the planned changes to the plane and because acquiring parts and equipments. The planes were finally delivered between summer of 1941 and January 1942.

When the Winter War broke out Finland wanted to buy armament among others from Great-Britain. Great Britain accepted the request for 12 Blenheim Mk. IV's in December 1939. During the transfer flight one plane was lost and one was damaged. Others ten were got to Finland in January 1940. In February 1940 Great Britain was willing to sell next batch of Blenheims. These 12 Blenheim Mk. I's arrived to Finland at the end of February 1940. These planes had British style bomb racks only for 454 kg bomb load. Part of these planes may have been former RAF's night fighters and they were converted back to bombers before flying to Finland.

In June 1941 Staff of the Finnish Air Force asked State Aircraft Factory to offer a batch of 10 Blenheim Mk. I's. When it was made possible to buy Polish licence built Mercury engines from Germans war booty depots and Yugoslavian Ikarus licence built Blenheim parts (e.g. a jig of Blenheim Mk. IV's nose and drawings) the order was rised to 30 planes. The planes were delivered to Air Force between April and December 1943.

Blenheim parts bought from the German war booty depots made it possible to order additionally ten Blenheim Mk. IV's at the end of 1941. The parts were get to Finland in the first half of 1942 and the planes were completed between February and April of 1944. In 1943 was made a decision to build still five Blenheims from spare parts but the plan was stopped in July 1944 and the parts were used for repairing damaged planes.

In 1951 Valmet Oy "repaired" BL-106 and BL-197. Because both planes had destroyed almost totally "fixing" the planes ment practically same as building new planes. When the planes were completed they might have had only few parts from the original planes, maybe no parts at all. This was done to save licence tariff. Depending on counting style Finnish Air Force had 97 or 98 Blenheims of wich 55 or 57 was built in Finland and 42 in England.

Finnish Blenheims were devided to series as follow:

Series I: 18 Blenheim Mk. I's built in Britain, open bomb bays (BL-104..BL-121). To service 1938.
Series II: 15 Blenheim Mk. I's built in Finland, enlarged bomb bays (BL-146..BL-160). To service 1941.
Series III: 12 Blenheim IV Mk. IV "long nose" planes built in Britain (BL-122..BL-133). Arrived to Finland 21.1. 1940.
Series IV: 12 Blenheim Mk. I's built in Britain (BL-134..BL-145). Arrived to Finland 26.2. 1940.
Series V: 30 Blenheim Mk. I's built in Finland (BL-161..BL-190). To service 1943.
Series VI: 10 Blenheim Mk. IV "long nose" planes built in Finland (BL-196..BL-205). To service 1944.

Series VI "long nose" planes could carry 972 kg bomb load while Series III and IV planes could carry only 523 kg bomb load. State Aircraft Factory modified bomb bays, bomb racks and bomb bay doors to accommodate bigger bombs during the major overhauls.

Service in Finland

During the Winter War Finnish Air Force flew 423 bomb raids and during the Continuation War about 3000 raids. Blenheim rear gunners had also five kills of which two were achieved with one plane on one mission. Finnish Air Force lost half of it's 97 Blenheims during bombing missions. During the Winter War the small number of planes and their small bomb load was sometimes compensated by adding a fourth man to the plane who fired tightly packed enemy columns on the forest roads with Suomi-submachine gun from low-flying plane.

During the so called "Temporary peace" time one Blenheim Mk. IV, BL-130, was lended to Germany for testing and familiarization between September and December of 1940. Blenheims were used as turget tugs and aerial photography until 1958.

Versions:

Blenheim Mk I
Two engined light/ medium bomber equipped with two 840 hp (630 kW) Bristol Mercury VIII radial engines. Armament consisted of one 7,7 mm (0,303 in) machine gun in the left wing and one 7,7 mm (0,303 in) Vickers K machine gun in hydraulically driven dorsal turret. Maximum bomb load changed depending on type of the bomb bay or type of the bomb racks. British built planes had a maximum bomb load of 454 kg whereas Finnish built "Series V" Blenheim Mk. I could carry 972 kg of bombs. In all 1552 Blenheim Mk. I planes were built. Company's type marking was "Type 142M".

Blenheim Mk IF
Long range heavy fighter armed with an underbelly arrangement of four 7.7 mm (0,303 in) machine guns. Part of the planes were later equipped with AI Mk III or Mk IV airborne radars and were used as night fighters. Approximately 200 Blenheim Mk. I's were converted to Mk. IF night fighters.

Blenheim Mk II
Long range reconnaissance version with greater amount of fuel. Only one Blenheim Mk. II was built.

Blenheim Mk III
Never materialized.

Blenheim Mk IV
Improved version with added armour. Longer nose comprised more room for observer/ bommer. Powered by two 905 hp (675 kW) Bristol Mercury XV radial engines. Armament consisted of one 7,7 mm (0,303 in) machine gun in the left wing and one or two 7,7 mm (0,303 in) machine guns in hydraulically driven dorsal turret. Late series Mk. IV's got increased defence armament with a rear facing under-defence gun under the nose (one or two 7,7mm [0.303 in] machine guns). These guns were sighted via periscope. Maximum bomb load was 454 kg (1000 lb). Totally 3307 Blenheim Mk. IV's were built.

Blenheim Mk IVF
Long range heavy fighter armed with an underbelly arrangement of four 7.7 mm (0,303 in) machine guns. Approximately 60 Blenheim Mk. IV's were converted to Mk. IVF fighters. British Costal Command used them to protect ship convoys against German bombers.

Blenheim Mk V
Was also known as Bristol Bisley. Heavily armoured close air support bomber armed with bombs and four 7.7 mm (0,303 in) machine guns (1000 rounds/gun) in it's solid nose. Powered by two Bristol Mercury XV or XXV radial engine. Dorsal turret was redesigned for two machine guns and the rear facing under-defence armament under the planes nose had now two 7,7mm (0.303 in) machine guns. These guns were sighted via periscope. Landing gear doors were redesigned and now there were two doors on each engine cowling. When France was occupied in 1940 usage of the plane was changed to bomber. Armour was removed as well as nose armament and "glaze nose" was reverted. This change wasn't successful and the outcome was a cramped space for observer /bomber. Plane wasn't liked amongst the crews. Planes were used in the Middle East and in the Far East. Totally 942 Blenheim Mk. V's were built.

Museum planes in Finland:
BL-200 Finnish Air Force Museum

Crew	3
Powerplant	2 × Bristol Mercury VIII -9-sylinder radial engine; 626 kW (840 hp) per engine
Dimensions	Lenght: 12,12 m; Wingspan: 17,17 m; Height: 2,98 m; Wing area: 43,57 m²
Weights	Empty weight 4 126 kg, max. takeoff weight 6 960 kg
Performance	370 km/h at sea level, 430 km/h at 5 000 m, cruising speed 300 km/h
Operating time	4 h
Climb speed	11,5 min to 5 000 m
Armament	1–2 × 7,7 mm mg in wings; 1 × 7,7–7,9 mm mg in dorsal turret; bomb load varied between 454 kg – 972 kg
Designer	Bristol Aeroplane Company
Production	1552 Blenheim Mk.I ; 3307 Blenheim Mk. IV ; 942 Blenheim Mk. V
Users	Great Britain, Australia, Canada, Republic of China, Independent State of Croatia, Finland, France, Greek, India, New Zealand, Poland, Portugal, Romania

Sources:

Blenheim Suomessa (Igor Kopiloff), IPMS Finland ry
Suomen Ilmavoimien Historia 10 (Kalevi Keskinen, Kari Stenman, Klaus Niska), Tietoteos
Blenheim laivue; Lentolaivue 42 sodassa (Kari Stenman), KOALA
Suomen ilmavoimien pommittajat; Historia, maalaukset ja merkinnät 1939-1945 (Kari Stenman‚ Karolina Holda)
Wikipedia: Bristol Blenheim (fi)
Wikipedia: Bristol Blenheim (en)
The WorldWars.net
Flightforum.fi: Blenheim keskustelu
Key.Aero

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