Blohm & Voss BV 155

The Blohm & Voss BV 155 was a German high-altitude interceptor aircraft intended to be used by the Luftwaffe against raids by USAAF Boeing B-29 Superfortresses. 
Work started on the design as the Messerschmitt Me 155 in 1942, but the project went through a protracted development period and change of ownership, and prototypes were still under test and development when World War II ended.

Performance estimates of the American B-29 Superfortress reached German command in early 1942. The bomber would cruise at an altitude at which no current German plane could operate effectively. To intercept it, the Luftwaffe would urgently need new aircraft. Work on such a high altitude fighter was begun by Messerschmitt, but in 1943 the project was passed to Blohm & Voss. The result would be the Bv155 prototype that made its first test flight in September 1944.
                 
Me 155
The story of the BV 155 began at Messerschmitt in the spring of 1942. A requirement had arisen for a carrier-based single-seat fighter to be based aboard the aircraft carrier Graf Zeppelin, then under construction. In response, Messerschmitt proposed the Me 155. In the interest of economy and simplicity, it was to use as many Messerschmitt Bf 109 components as possible, being basically a navalized version of the earlier Messerschmitt fighter.

The Me 155 was to be powered by a DB 605A-1 liquid-cooled engine of 1,475 PS (1,455 hp, 1,085 kW). The fuselage was more or less that of the standard Bf 109G, but with an entirely new wing. The undercarriage retracted inwards into wing wells, providing the wider track required for safe carrier landings. Standard naval equipment such as folding wings, catapult spools, and arrester gear were to be fitted. Proposed armament was an engine mounted 20 mm MG 151 cannon and two 20 mm MG 151 cannons and two 13 mm MG 131 machine guns in wings. It had an estimated maximum speed of 649 km/h.

Detail design of the Me 155 was complete by Sept 1942. However, the numerous delays in the Graf Zeppelin seemed to indicate that the completion of the carrier would be at least two years away. Messerschmitt was told to shelve the Me 155 project for the indefinite future. Work on the Graf Zeppelin carrier was eventually abandoned.

Me 155A
In order that all of that work on the Me 155 project not go entirely to waste, Messerschmitt adapted its design in November 1942 to match a Luftwaffe requirement for a fast single seat bomber. A single 1,000 kg SC1000 bomb was to be carried. All of the carrier equipment and most of the armament was removed from the aircraft. Additional fuel tanks were provided and an elongated, non-retractable tailwheel was added to provide ground clearance for the large bomb. The proposal was designated Me 155A.

Me 155B
By the end of 1942, the increasing number of USAAF bombing raids and intelligence coming in about the new American B-29 bomber led the Luftwaffe to envisage a pressing need for an effective high-altitude interceptor. Messerschmitt adapted the Me 155 design again to meet this requirement, merging the design with an in-house study originally designated Me 409, then later Bf 109ST; the new aircraft received the designation Me 155B. The engine was to be the DB 628, which was basically a DB 605A with a two-stage mechanical supercharger with an induction cooler. A pressurized cabin was to be provided. It was estimated that a service ceiling of 14,097 m, could be attained.

A converted Bf 109G adapted to take the DB 628 engine flew in May 1942 and attained an altitude of 15,500 m. However, the Technische Amt concluded that a DB 603A engine with an exhaust-driven turbosupercharger was more promising. The DB 603A provided 1,201 kW (1,610 hp) for takeoff and 1,081 kW (1,450 hp) at 15,000 m. This engine change required that the fuselage be elongated in order to house the turbosupercharger aft of the pressure cabin. Exhaust gases were carried to the turbosupercharger via external ducts. Air was drawn in through via a ventral trough aft of the wing. Standard Bf 109G wings were to be fitted outboard of a new, long-span, untapered wing center section. Other parts were scavenged from existing Messerschmitt designs – the vertical tail was from the Me 209, and the horizontal tail and the undercarriage were taken from the Bf 109G.

In August 1943, the RLM realised that Messerschmitt was over-committed and transferred the design work to Blohm & Voss. The design team there came to the conclusion that the existing Messerschmitt design had too many weaknesses and a complete redesign would be necessary.

In September 1943, an order for five prototypes was placed. Blohm & Voss accepted the order only on condition they had complete design freedom and were not bound by Messerschmitt's work to date. The redesign was named the BV 155. B&V gave it a new laminar flow wing and tail unit, landing gear from the Ju 87 and many other parts of the plane. Further wind tunnel testing showed that there was a serious problem with the overwing radiators, at high angles of attack the wing "blanked" them from the airflow and cooling would suffer. Work moved to a revised B model.
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General

Number built 3
Length: 12 m Crew: 1
Wingspan: 20.5 m
Height: 3 m
Wing area: 39 m2
Empty weight: 4,870 kg
Gross weight: 5,520 kg Proposal A
5,125 kg Proposal B
5,100 kg Proposal C
5,440 kg  Proposal D
Max takeoff weight: 6,020 kg
Fuel capacity: 1,200 l 
Powerplant: 1 × Daimler-Benz DB 603A inverted V-12 liquid-cooled piston engine with TKL 15 turbo-charger, 1,200 kW (1,600 hp) for take-off
1,200 kW at 10,000 m
1,081 kW at 15,000 m 
Propellers: 4-bladed constant speed paddle bladed propeller

Maximum speed: 420 km/h at sea level
520 km/h at 6,000 m 
600 km/h at 10,000 m 
650 km/h at 12,000 m 
690 km/h at 16,000 m 
Range: 460 km at maximum continuous power with 595 l of fuel at sea level
560 km  with 595 l of fuel at 10,000 m 
590 km with 595 l of fuel at 16,000 m
1,080 km with 1,200 l  of fuel at sea level
1,350 km with 1,200 l  of fuel at 10,000 m 
1,440 km with 1,200 l of fuel at 16,000 m 
Service ceiling: 16,950 m service ceiling
maximum ceiling 17,100 m
Rate of climb: 11.5 m/s initial
3.92 m/s at 16,000 m
Time to altitude: 16,000 m in 29 minutes

Guns: 
Proposal A
1 × 30 mm MK 108 cannon as an engine mounted Motorkanone firing through the propeller shaft
2 × 20 mm MG 151/20 cannon
Proposal B
1 × 30 mm MK 103 cannon as an engine mounted Motorkanone firing through the propeller shaft with 60 rounds
2 × 15 mm MG 151 cannon with 200 rpg
Proposal C
3 × 30 mm MK 108 cannon with 60 rpg.
Proposal D
3 × 30 mm MK 103 cannon with 60 rpg (two mounted in under-wing fairings).

                      
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The first prototype, BV 155 V1, took off for its maiden flight on September 1, 1944. Tests with the V1 showed that the outboard radiators provided inadequate cooling, especially at high angle of attack. The intakes on the next prototype were enlarged and underslung beneath the wing rather than placed over it. However, the enlarged radiators caused a CoG problem, which required moving the pressurized cockpit forward. The Blohm & Voss team took this opportunity to replace the original Bf 109G canopy with an aft-sliding all-round vision canopy, and the rear fuselage decking was cut down. This in turn required that a larger rudder be fitted. The ventral radiator bath was also enlarged.

With these changes, the BV 155 V2 flew on February 8, 1945. Blohm & Voss was still not satisfied with the design, and before the V2 began its flight trials they proposed that the engine be switched to the DB 603U having the larger mechanically driven supercharger of the DB 603E. 

The DB 603U promised a power of 1,238 kW (1,660 hp) for takeoff and 1,066 kW (1,430 hp) at 14,935 m. The ventral turbosupercharger was retained. The Technische Amt decided to accept this proposal, and abandoned all work on the BV 155B in favor of the revised design, which was designated BV 155C.

The BV 155 V2 was damaged beyond repair during a bad landing. It was to be replaced in the test program by the BV 155 V3. The BV 155 V3 differed from the V2 in having the DB 603U intended for the BV 155C. However, the engine cowling and turbosupercharger were unchanged.
                 
Various armament schemes for the BV 155B were proposed. One proposal had an engine-mounted (or Motorkanone) 30 mm MK 108 cannon and two 20 mm MG 151/20 cannons. Another had a Motorkanone-mount 30 mm MK 103 cannon and two wing-mounted 20 mm MG 151 cannons. Estimated maximum speed was 650 km/h at 12,000 m and 690 km/h at 16,000 m. Service ceiling was to be 16,950 m. Empty weight was 4,869 kg. Normal loaded weight ranged from 5,126-5,488 kg, depending on the armament provided.

According to Pegasus Models Kit No. 5002 information sheet, V1 and V2 were both provided to the RAF after the war. V1 was flight tested until it was written off. The fate of V2 is not known. V3 is in storage at the US Air And Space Museum's storage facility.

BV 155C Project
In parallel with the prototype development, Blohm & Voss had been working on additional changes under Project 205. P.205 replaced the underwing radiators with an annular one around the front of the engine, a design feature commonly found on a number of German designs. With the wings now free of clutter, they were considerably simpler and were reduced in span. This also had the side effect of reducing the track, which would later prove to be a welcome change. 

The new design would be simpler, lighter and faster, and plans were made to make it the standard version of the aircraft. During the October re-evaluation, it was agreed that V1 through V3 would be completed as B models, while a new series of five would be completed to the new standard as the BV 155C.

The BV 155C was to be significantly different in appearance from the BV 155B. The clumsy wing-mounted radiators of the BV 155B were eliminated, and the main landing gear leg attachment points were moved inboard to retract inwards. Cooling was provided by an annular frontal radiator as in the Focke-Wulf Ta 152. Large circular intakes were attached to the fuselage sides above the wing roots.

Lauri Nissinen

Lauri Nissinen (31 July 1918 in Joensuu – 17 June 1944 in Kaukjärvi) was a World War II flying ace in the Finnish Air Force.

Lauri Vilhelm Nissinen was born in Joensuu on 31 July 1918 and for his compulsory military service joined the Air Force, during which time he decided on flying as a career, applying for NCO pilot training in 1938. Due to his performance during training he joined HLeLv 24, flying the Fokker D.XXI in May 1939. In summer 1939 he was promoted to Sergeant.

As the Winter War broke out, Sgt. Nissinen first claimed an air victory on 1 December 1939, claiming a SB-2 shot down and damaging two others over Viipuri. By the end of the Winter War he had claimed four victories in total and was a Sergeant Major.

                       

HLeLv 24 then equipped with the US- built Brewster Buffalo. As hostilities broke out again on 25 June 1941 Nissinen again flew operationally. On 7 July 1941 over Käkisalmi two enemy fighters attacked head-on, Nissinen shooting down both. On 21 July 1941 he again shot down a I-153 in a head-on battle, although his aircraft was damaged and he returned to base. His ground crew found four hits in the engine, one in the prop and several more in the wings.

On 1 August 1941 at Rautjärvi six Buffalos engaged eight Soviet I-16 fighters, Nissinen's target exploding and its debris damaged Nissinen's right wing. Three I-16s attacked from behind and his fighter took several hits, shattering the windscreen.

At the end of 1941 Nissinen was the second highest scoring FAF ace with 15.5 kills. Early in 1942 Nissinen attended Officer Cadet School, from where he then graduated in June 1943 as a Lieutenant.

                       

                       

                       

Nissinen was awarded the Mannerheim Cross on 5 July 1942, his number being 69. He held the rank of vänrikki (second or under lieutenant) at the time.

Returning to HLeLv 24 Nissinen was made a flight commander and resumed flying missions. His score increased to 26 by the end of 1943. The squadron gradually re-equipped with Messerschmitt Bf 109 fighters in spring 1944.

In May 1944 HLeLv 32, flying the Curtiss P-36, was temporarily strengthened with a Messerschmitt Bf 109G-2 flight commanded by Lt. Nissinen.

On 16 May Nissinen scrambled against a single Lavochkin La-5 approaching Nurmoila. The La-5 circled at 1500 m and allowed Nissinen climb to the same altitude before turning to attack from above, shooting down the La-5 after a series of exhausting attacks.

With the renewed Soviet offensive on 9 June 1944 Lt. Nissinen scored two more victories on 17 June 1944 as two flights intercepted Soviet Il-2 ground attack aircraft attacking Finnish positions at Kaukjärvi. 

Nissinen's wingman, Sgt. Heimo Lampi saw the crippled Messerschmitt of Lt. Sarjamo dive through the cloud and collide with Nissinen's plane. Both planes exploded on impact and the pilots were killed.

Lieutenant Jarmakov had fired a second wing from Lieutenant Urho Sarjamo's machine, and this caused Mersu falls at Sarjamo Nissinen Mersu.

Nissinen flew some 300 missions and scored 32 victories in total. His grave is in Valkeala.

Croatian Air Force Legion

The Croatian Air Force Legion (Croatian: Hrvatska Zrakoplovna Legija), or HZL, also known as the Croatian Legion , was a foreign volunteer unit of the Luftwaffe raised from volunteers drawn from the Independent State of Croatia which fought on the Eastern Front between 1941–1943 in the Second World War. It was then absorbed by the Air Force of the Independent State of Croatia and its surviving members fought back on Croatian soil. The legion had approximately 360 men. 

The unit was sent to Germany for training on 15 July 1941 before heading to the Eastern Front. Many of the pilots and crews had previously served in the Royal Yugoslav Air Force during the Invasion of Yugoslavia in April 1941. 

Some of them also had experience in the two main types that they would operate, the Messerschmitt 109 and Dornier Do 17, with two fighter pilots having actually shot down Luftwaffe aircraft. 

The Legion's commander was Ivan Mark. During operations over the Eastern Front, the unit's fighters scored a total of 283 kills while its bombers participated in 1,332 combat missions. 

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The Legion was organized into a fighter wing and a bomber wing:

4. Fighter Wing (Major Franjo Dzal)

10. Fighter Squadron

11. Fighter Squadron

The 4. Fighter Wing was attached to the Jagdgeschwader 52 . It originally served as part of the III./JG 52 , while later it became known as the 15(Kroat.)/JG52 . It was led by Franjo Džal .

5. Bomber Wing

12. Bomber Squadron

13. Bomber Squadron

The 5. Bomber Wing was originally attached to Kampfgeschwader 3 as part of the 10/KG3 and later as the 15.(Kroat.)/KG 3 .

Fighter operations over the Eastern Front 1941-44 

                        

                        

Croatian Pilot Mato Dukovac, in front of his Messerschmitt 109 G fighter on the Eastern Front, 1942. He was the top-scoring Ace of the Croatian Air Force Legion with 44 confirmed victories against the Soviet Air Force. Note the Legion's crest below the aircraft cockpit.

One squadron of the Fighter Wing was sent to the area of Furth , Germany, for training, the other to Herzogenaurach Airfield, nearby. Training commenced on July 19, 1941, on Arado 96 and Messerschmitt 109 D aircraft, and lasted to the end of September 1941 at which time the Legionnaires were deemed ready for the Eastern Front and were equipped with various models of the Messerschmitt 109 fighter. During the course of their training, the men had been issued Luftwaffe uniforms adorned with the Croatian armshield and the Croatian Airforce Legion badge on the right breast pocket.

The Squadron received the official designation '15.(Kroatische)/JG 52', and arrived to its first Eastern Front airfield on October 6, 1941, near Poltava. On 9 October 1941, the Squadron has its first taste of action, when, in the Ahtijevka-Krasnograd area, a Soviet R10 was shot down. The kill was given to the German liaison pilot to the Squadron, Lt. Baumgarten. The Squadron was transferred at the end of October 1941 to Taganrog, and stayed in this area till 1 December 1941. The first kill by a Croatian pilot occurred in this time period by Captain Ferencina, and the second by Lt.Colonel Dzal.

On 1 December 1941, the Squadron transferred to Marinpol. Attacks were made on Soviet armoured columns around Pokorovskoje, Matvejeva, Kurgan, Jeiska and Uspenskoje, and on the railway line Marinpol-Stalino. As well, the Squadron escorted German bombers on their missions. By the end of January 1942, the Squadron had shot down 23 Soviet airplanes (of this, four were MIG-3 fighters). 

At the end of March 1942, the Squadron received a telegrams from the Commander of 4.Fliegerkorp, General Flugbeil, and the Commander of 4.Luftflotte, Colonel-General Lohr, congratulating them on their successes. In April 1942, the Squadron flew escort missions for Stuka bombers, guarded the Marinpol airfield, and strafed Soviet troops in the Azov Sea area. Nine more Soviet airplanes were shot down in this period.

In May, the Squadron was transferred first to the Crimea, and shortly thereafter, to the Artemovka-Konstantinovka region. From this base of operation, the Squadron flew escort missions for bombers attacking Sevastopol and patrolled the Azov Sea area. Four more Soviet planes were downed, and a Soviet patrol boat was also sunk. From the end of May, till 21 June 1942 (the date of the Squadron's 1000 flight), 21 more Soviet planes were shot down. From this date till the end of July 1942, 69 more aircraft are shot down.

At the end of 1942 the unit was given a three-month rest, returning to Nikolayev on 21 February 1943. Although the unit continued to score kills, there was a spate in defections from 15./JG 52, with pilots flying to Soviet airfields. The remaining pilots were questioned by the Luftwaffe, the Staffel was withdrawn from the front, and the commander of the HZL was replaced. This was the end of the second tour of 15./JG 52 on the Eastern Front. 

The Luftwaffe decided to replace most of the remaining pilots of 15./JG 52 with newly trained men, and several veterans of the Staffel joined them during their fighter training at Fürth. Twelve graduated on 1 October 1943 and they arrived with two other pilots at Nikolayev on 21 October 1943, where they were equipped with eight Bf 109G-4s and G-6s. They deployed to their airfield at Bagerovo and commenced combat missions on 26 October. By late 1943 the Squadron had tallied 283 kills, and had 14 pilots who had gained Flying ace status. 

The Squadron continued with its fine performances until March 1944 when the Luftwaffe decided that attempting to maintain 15./JG 52 was futile, and the men were sent home to the NDH to help to combat the increasing air activity over the Balkans by the Allies . During its three tours, the Staffel had accounted for a total of 297 Soviet aircraft when it was re-deployed to Croatia.

At least part of the unit returned to the Eastern Front when, at the beginning of July, the Luftwaffe reconsidered its decision. They were transported to Romania and then the Slovak Republic, but no aircraft were provided, and on 21 July the pilots were advised that the HZL was to be disbanded. Despite this, in August they were moved to an airfield in East Prussia, where they took delivery of ten Bf 109G-14s. At the beginning of September they flew to Lithuania in preparation to rejoin the fray, but the defection of squadron leader Mato Dukovac led to the cessation of Croat aerial operations on the Eastern Front.
                  

                      

Bomber operations over the Eastern Front 1941-42 

Officially designated '15.(Kroatische)/KG 53'., the bomber squadron was equipped with Dornier Do 17 Z aircraft. It arrived on the Eastern Front on 25 October 1941, after training at the Grosse Kampfflieger Schule 3, in Greifswald, Germany. Their first area of operations was near Vitebsk. The rest of the Bomber Squadron's assignments were in the Northern Sector of the Eastern Front, including the bombing of Leningrad and Moscow. On 9 November 1941, the Squadron was congratulated by Fieldmarshall Kesselring for its actions thus far. After flying some 1,500 sorties on the Eastern Front, the Squadron and its aircraft were re-deployed to Croatia in December 1942, to help combat the growing Partisan threat to the Axis forces in occupied Yugoslavia.

Fighter operations over Croatia 1944-45 

In early 1944 the squadron was redesignated 1./(Kroat.)JG but remained in the Crimea on the Eastern Front. Around the same time two new units were formed to defend the airspace over Croatia. The crews for 2. u. 3. Staffel were drawn from Croatian pilots who had recently completed an A/B course at a German flight school in Bohemia followed by a Bf 109 fighter school in France. 

They returned to Croatia in early January 1944 and were assigned to Velika Gorica where the two Staffeln were to be formed. Plans to outfit the Staffeln with Bf 109s were canceled, and at the end of January the pilots of the 2. Staffel ( 2./(Kroat.)JG ) went to Italy to collect around a dozen Macchi C.202s and Fiat G.50s. The 3. Staffel was an operational training squadron, also known as 3./(Kroat.)JG and equipped with Macchi C.200 and Fiat CR.42 fighters. All these aircraft retained their Luftwaffe markings whilst in service with the unit.

After a period of operational conversion, the squadrons commenced operations against the frequent incursions over Croatia by USAAF and RAF aircraft. By April 1944 1./(Kroat.)JG ahd been withdrawn from the Eastern Front and its crew returned to NDH. During a period of intensive activity over the summer of 1944, the squadrons claimed some 20 Allied aircraft shot down, while at the same time receiving further Macchi C.202s , as well as several brand new Macchi C.205s.

By the end of 1944 the squadrons had handed in their remaining worn-out Macchis for brand new German Messerschmitt 109 G & K fighters. Over 50 Messerschmitts were delivered to the squadrons and the Air Force of the Independent State of Croatia , with the final delivery taking place on 23 April 1945.

Bomber operations over Croatia 1943-45 

Upon its return the Legion's bomber squadron was redesignated 1./(Kroat.)KG after having flown its nine Dornier Do 17 Z bombers from Russia back to Croatia. The Dorniers proved a welcome addition to the strike power of the Axis forces fighting the Partisans in occupied Yugoslavia right up to the end of July 1944, when it was incorporated into the ZNDH.  In late 1943, a second squadron, 2./(Kroat.)KG was formed to provide operational training. It was equipped with Italian designed and built CANT Z.1007 and Fiat BR.20 bombers.

Heinkel He 118

The Heinkel He 118 was a prototype German monoplane dive bomber design that lost out to the Junkers Ju 87 Stuka in the 1930s, and was never ordered by the Luftwaffe .

Designed by the Günter brothers , the He 118 followed many of the design notes of the Günter's designs of the era, notably the elliptical wing planform and rounded tail surfaces. It was in many ways an aluminum version of the mixed-construction Heinkel He 70 Blitz , strengthened for dive bombing.

It was a conventional cantilever monoplane with an inverted gull wing of elliptical planform mounted midway up the fuselage . It was considerably more streamlined than the Junkers competitor, with retractable landing gear and an internal bomb bay .

As designed it was limited to filling a role similar to an attack bomber like the Henschel Hs 123 rather than a true dive bomber like the Junkers Ju 87. It was limited to bombing from a shallow angle, more properly known as "glide bombing", with the second crew member acting as the bomb aimer.

                 

Production and testing 

In trials, it was discovered that the maximum dive angle was only 50°. In June 1936, Ernst Udet took the He 118 on a test flight but after commencing his first dive from about 13,000 feet the propeller suddenly feathered, shearing the reduction gears, and the He 118 disintegrated, leaving Udet to parachute to safety. The Ju 87 repeatedly demonstrated dives at 90 degrees with no trouble, and so won the contract.

                 

Heinkel complained in his biography that Udet ignored instructions and flew the aircraft outside of its limits. He suggests that the failure doomed his design, in spite of being unable to dive vertically like the Stuka.

Of the 15 He 118s built, two went to Japan where they were designated DXHe , however the aircraft disintegrated during Japanese flight tests. The 13-Shi (1939) design specification that led to the Yokosuka D4Y naval dive bomber may have been inspired by the He 118, but otherwise the two aircraft had little in common. 

Heinkel used another example as a flying testbed for the Heinkel HeS 3 turbojet , with the jet engine slung under its fuselage. Although its pilot took off and landed using the He 118's piston engine, he started the turbojet engine in flight and flew under its power in July 1939, the first time an aircraft flew under jet power. The following month the similarly powered, fixed conventional landing gear -fitted Heinkel He 178 V1 would make the first flight powered entirely by a turbojet engine. 

Variants 

He 118: Dive bomber prototypes.

He 118A-1 : Eight production aircraft, powered by a 634 kW (850 hp) DB 600 C engine.

                

DXHe1: Two He 118s supplied to the Imperial Japanese Navy Air Service for evaluation in 1938.

Specifications (He 118A-01)

Crew: Two

Length: 11.81 m 

Wingspan: 15.10 m 

Height: 4.19 m 

Wing area: 37.71 m² 

Empty weight: 2,705 kg 

Loaded weight: 4,128 kg 

Powerplant: 1 × Daimler-Benz DB 600 C 12-cylinder liquid-cooled supercharged piston engine, 679 kW  at 4,000 m 

Maximum speed: 394 km/h at 6,000 m 

Cruise speed: 335 km/h  at 4,000m

Range: 1,050 km 

Climb to 2,000 m 

Guns:  2 × fixed forward-firing 7.9 mm MG 17 mg +  1 × flexible rearward-firing 7.92 

Bombs: Up to 500 kg of bombs