Apophenia's Offerings

[apophenia]

Cheers Vuk! Here's some more ...

Yugoslav Blenheim Developments - Future Plans and Bura Production

The ultimate plan for the Yugoslav Blenheim was an aerodynamic 'clean up' to suit the aircraft to both the light bomber and the attack role. To that end, Ikarus AD engineers S. Momcilovic and D. Radojkovic were assigned the task of adapting the drag-reducing nose and single-seat cockpit section from their private-venture Orkan (Hurricane) design to the Blenheim fuselage.

The result was to be the Bura B.5. The design had a noticeable 'step' in the underside of its forward fuselage. This was to accommodate a heavier forward-firing armament for the anticipated attack role. Initially, it was thought that this armament would consist of a pair of Hispano-Suiza HS-404 cannons - one installation replacing each forward bomb bay.

When supplies of the French guns dried up, Momcilovic and Radojkovic turned first to the German Oerlikon MG FF and then to Italian 12,7 mm heavy machine guns. It was assumed that the B.5 would be powered by Piaggio P.XI radials as on the P.3P testbed but this was not to be.

The proposed B.5 was eclipsed by a simpler productionized form of the B.3P. The B.6 was a refined B.3P with equipment substituted to better suit the Kingdom of Yugoslavia's role as a member of the Axis alliance. Having made clear that Yugoslavia would take no part in any attack on fellow Slavs in the Soviet Union, Belgrade found itself given a lower priority for German exports. as a result, the B.6 series relied heavily upon Italian suppliers.

Other than the Piaggio engines, notable changes from the B.1 series included the substitution of the main undercarriage members from the Fiat CR.25, the replacement of the Bristol B.I dorsal turret with a manually-operated Caproni-Lanciani Delta (armed with a 7,9 mm Scotti-I.F. M1932/jugoslavo), and the use of Regia Aeronautica radio equipment.

Bottom: A freshly-delivered Ikarus B.6/I light bomber due for the 62nd Bomber Group.

__________________________________________________

[Vuk]

My first thought on B.5 was - heavy/night fighter...

[Tophe]

  The Bura B.5 is just lovely...

[apophenia]

Yugoslav Blenheim Developments - Export Bura Variants

The Alfa-engined B.7 actually predated the VVJK's Bura B.6. The B.7s were final production Bura B.1s fitted with 780 hp Alfa Romeo 126 RC.34 engines inherited from SM.79P bombers. The Alfas were available but the VVJK knew from the B-2R engine testbed that the B.7 would  be underpowered. As a result, it was decided to complete all Alfa powered Buras as dual-control B.7 Treners (or B.7/Ts).

A surprise request came from the Regia Aeronautica. Since the Italians were already flying Bura B.1f photo-reconnaissance aircraft (in mock RAF markings), it was decided that a pilot conversion trainer was also needed. The B.7/T -- or B.7 D.C. for Doppio Comando -- filled this role without additional wear on the more valuable Bristol Mercury radials.

Top: A B.7 D.C. assigned to the 2ş Gruppo aviazione Presidio Coloniale, Aviazione della Cirenaica. Italian B.7s were fitted with sliding gun hatches for self-defence. It seems that this modest arrangement was inadequate --  on its delivery flight to Libya, this aircraft was shot down by intercepting RAF Beaufighters out of Malta.

The more streamlined B.5 nose was first introduced to the production line with the Bura B.8 series. Export interest in this variant came from the Romanian FARR. While the VVJK's B.8s retained the Piaggio P.XIs of the B.6, the export B.8Ru (Rumunjski) was fitted with IAR 14K  radials. These aircraft were assembled by IAR at Brașov from kits supplied by Ikarus AD.

Bottom: A third series B.8Ru/III (or IAR B.8C) of the FARR's Escadrila 1 recunoastere. These aircraft were armed with single 7,9 mm Scotti or FN guns in the Lanciana Delta dorsal turret and twin, forward-firing 13.2mm FN machine guns under the cockpit.

BTW: The B.8Ru was based on a FARR Blenheim Mk.I profile by Bogdan Pătraşcu.

_____________________

[Tophe]

Impressive family!

[GTX_Admin]

Those last two look great! :)

[apophenia]

Yugoslav Blenheim Developments - Replacement Concept and 'Bura V-12'

Several attempts were made to develop the MR-1 Orkan design to fill roles unsuited to the Bura. One such was an Orkan-based hybird using Bura wings, the MR-4 Oluja (Tempest).

Top: MR-4 Oluja concept in its Piaggio P.XI-powered form.

The object of the MR-4 Oluja design was to produce a capable torpedo bomber. The scheme appears to have been workable but the VVKJ elected to procure more SM.79Ps from Italy to fill this role.

A constant challenge for Ikarus designers was finding higher-powered engines for the Bura. Having been constantly thwarted in their attempts to procure DB601s, Ikarus turned to Soviet Klimov M-105A V-12s from captured by the Germans and then offered for sale.*

The Bura B.10 was an inline engine testbed modification of the radial-engined Bura B.8. The Bura B.10S (Sovjetski) with Klimov M-105As was the first flown. The modification was a complete success and a small production series was prepared. However, before any production B.11S was completed, VVKJ planners redirected all available Klimov engines to fighter re-engining programs.

Bottom: Bura B.10S testbed. Note the mix of markings. Underwing roundels are the original Axis VVKJ design. Added fuselage roundels are of the later, simplified design. Note that both those fuselage roundels and nacelle recognition markings are in the later pale grey (rather than pure white). The dorsal turret was later removed.

_________________

* Those M-105A engines intended for the Bura B.11 lacked gun syncronization. Klimov engines with syncronization were allocated to Rogožarski for use in fighters.
_________________

[apophenia]

Yugoslav Blenheim Developments - A Southern Wind and Fiat Power

Development of the Bura B.10S was cut short when the VVKJ demanded the return of its Klimov M-105A engines. Tests had shown improved climb and top speed performance but found the aircraft somewhat lacking in directional control. Twin tailplanes were designed but not fitted before the V-12 engines were removed.

A potential solution to the B.10 prototype's engine problem arose from the demise of another Ikarus project -- the MR-2 Jugo (Sirocco or 'South' wind), a low-winged Orkan derivative. With the MR-2 shelved, its Fiat A.74 radials were available. At 870 hp, the Italian engines lacked the Klimov's power but the Fiats' smaller diameter better suited them to re-engining the B.10S than any other available powerplants.

Top: Ikarus MR-2 Jugo concept as a light bomber. Note smaller Orkan-style fins (compared with MR-4 Oluja concept, above).

Accordingly, the B.10S was fitted with both Fiat A.74 RC.38 engines and the twin tails intended for higher-powered Bura derivatives. Both were a complete success and Ikarus proposed fitting Fiat radials to the engineless B.11S airframes nearing completion on their production lines. It was envisioned that the resulting B.11Fs would suit the VVKJ as dual control trainers for more powerful operational Bura variants.

Bottom: Bura B.10F (Fiat) testbed shown after the fitting of twin tails. Note that the Underwing roundels have been repainted in the simplified design. Oddly, nacelle recognition markings have reverted to pure white rather than the by-then appropriate pale grey. The Fiat-supplied cowlings are the same as those for the CR.42 fighter.

_________________

[Tophe]

Elegant lines!

[Vuk]

A, You made my day!  :)

[apophenia]

Thanks folks!

As mentioned, the VVJK decided to allocate all available 'war-booty' Klimov M-105 engines to fighter programs. Engines lacking gun synchonization went to Zmaj to re-engine Hawker Hurricanes with worn-out Merlins. The result was the 'Hariken-S'.

[Bottom] A newly refurbished 'Hariken-S' of 35. Grupa, 5. Lovacki Puk/3. Brigada, Leskovac (prior to dispatch to Thessaloniki, Greece). Note that White 7's markings are only partially applied - white paint has yet to be added to the fuselage roundel and the fighter's new, Luftwaffe-style individual aircraft number.

Synchronized Klimovs went to Rogožarski for IK-3/II re-engining and new-production IK-3/III Jastreb (Hawk) fighters. The later was readily distinguishable from early IK-3s by the upper cowling bulges for its synchronized 12,7 mm Breda-SAFAT guns (a third Breda fired through the hollow propeller shaft).

[Top] An IK-3/III Jastreb of 32. Grupa, 2. Lovacki Puk/1. Brigada at Krusevac. Fuselage mottling on 'Red 4' is more extensive than normal (with grey mottling extending into the recognition panels and even forms a 'Spiralschnauze' on the spinner!).
______________________

NB: Both of these sideviews began life as profiles by Srecko Bradic.

______________________

[Old Wombat]

Neat! :)

[finsrin]

MR-4 Oluga and MR-2 Jugo 

[GTX_Admin]

 :)

[apophenia]

Yugoslav Blenheim Developments - Buras with Inline Engines

Ikarus finally got access to the DB601 engines that it needed to increase Bura performance. Italy was prepared to allocated a small percentage of its licensed Alfa Romeo RA.1000 RC.41 Monsone powerplants to Yugoslav production. Thus was born the Bura B.12 variant.

The Bura B.12 was to be a torpedo bomber (to replace VVKJ SM.79s in that role). To ensure torpedo clearance, a larger tailwheel was used. Experience demonstrated that the twin tails for the earlier B.11S development were inadequate and these were replaced by larger tails. Another visual change was to the turret. The manually-operated Lanciana Delta dorsal turret was replaced by the powered German EDL 131 Drehturm.

[Bottom] The Bura B.12 prototype flew well (once fitted with enlarged tailplanes) but, even fitted with the Italian-made DB.601 engines, the aircraft did not have sufficient power to perform adequately as a torpedo bomber. This prototype was converted to Bura B.14 standards.

Also mooted was a float-equipped Bura torpedo bomber, the B.12H (Hidroplan) for the Royal Yugoslav Naval Aviation, KJRM-RM (Kraljevska Jugoslavenska Ratna Mornarica - Pomorskom vazduhoplovstvu). Priority for Monsone engines was given to VVKJ aircraft and no B.12H was floatplane completed.

The B.12 was not the first Bura fitted with inverted V-12 engines. When the VVKJ showed no interest in a Fiat-powered B.11F, Rumania saw an opportunity. IAR was willing to take the semi-finished B.11S centre sections as part of its planned Bura improvement to be powered by twin Junker Jumo 211Da engines. IAR produced its hybrid type by combining those B.11S centre section with Rumanian-built B.8C fuselages, tailplanes, and outer wing panels.

Ikarus AD knew these hybrids as the B.11Ru (or B.11Ju) but the Rumanians refered to the new type at the IAR B.8M. The higher power of the Jumo 211s dictated the addition of a dorsal fin extension to maintain stability. All B.11Ru/B.8Ms featured these dorsal strakes (the first three airframes being retrofitted after entering FARR service).

[Top] B.11Ru (IAR B.8C) of the FARR's Escadrila 2 Recunoastere. Defensive armament for these aircraft consisted of a single 7.9 mm FN machine guns in the manually-operated Lanciana Delta dorsal turret and another pair of forward-firing 7.9 mm FN guns under the cockpit.

NB: B.11Ru derived from a FARR Blenheim Mk.I by Bogdan Patrascu.
___________________________________

[Silver Fox]

Pretty birds!

I really like the torpedo bomber, very sleek looking.

[Tophe]

Surprising silhouettes, thanks!

[apophenia]

Thanks folks!

Yugoslav Blenheim Developments - Last of Ikarus' Bura Line

The VVKJ ordered that Bura production focus on the new Alfa-engined B.14 light bomber and reconnaissance model. However, the next production model was a hybrid of B.8 and B.14 parts. The B.15 preceded the B.14 into service and differed only in detail.

[Top] The Bura B.15 retained the fixed tailwheel of the B.8 as well as its Italian turret. Although painted in the standard late-war VVKJ maritime reconnaisance scheme, this aircraft was provided to the German Luftwaffe for trials at Rechlin.

To confuse matters further, the first production B.14s were really B.15 airframes fitted with German EDL 131 turrets. The Bura B.14/II series were the first to introduce the B.12's retractable tailwheel (as well as German radio equipment). This B.14/II defected to occupied Italy and has been given partial RAF markings.

Although not obvious here, the B.14/II standardized on the German MG131 for defensive -- both in the hydraulically-powered EDL 131 turret and fixed, forward firing guns. Light bombers had twin forward-firing guns, maritime attack models featured four fixed guns.
_______________

[GTX_Admin]

Sleek!

[apophenia]

OT for the Buran story but here's a pair of unbuilt Yugoslav fighter projects ...

In the summer of 1942, Eng. Dusan Stankov found himself overseeing the re-assembly of former Luftwaffe Bf 109B for use as VVKJ fighter-trainers at the ZMAJ factory at Zemun. Ideal 'lead-in' trainers for Yugoslav Bf 109E-3a Orao (Eagle) fighters, the 'Bs were also available in some numbers. Alas, there was also a shortage of Jumo 210 spares. That prompted two Bf 109B re-engining proposals.

The first was a scheme to turn surplus Bf 109B airframes into operational aircraft, the Orao B OVP (Operativni Vazduhoplovni Projekt). This OVB involved the installation of more powerful engines and, for fighters,increasing the armament. The two components of the Orao B OVP were the proposed Bf 109/BP (Brzog Presretaca or Fast Interceptor) and the Bf 109/BI (Brzog Izvidnika or Fast Reconnaissance aircraft).

Both Orao B OZP variants required engine changes. Proposed Jumo 210 replacements were either Hispano-Suiza HS 12Ys bought from Vichy France or Soviet Klimov M-105 V-12s from German war booty' stocks. In the event, neither engine was available and attention turned to another Bf 109B conversion, the Projekt za Napredno Trenera (Advanced Trainer Project).

The Orao NP (Napredni Trener) was to be a straightforward Bf 109B conversion, The Jumo 210 powerplant and radiator was to be removed and replaced by an Italian air-cooled V-12 -- the 700 hp Isotta-Fraschini Delta RC.35. At 510 kg, the Italian engine was slightly heavier than the 440 kg Jumo 210 but the weight of the radiator and coolant was to make up the difference. In the event, the Projekt za Napredno Trenera was restricted to keeping existing Bf 109Bs airworthy and no re-engining took place.

Another, more dramatic, fighter transformation was also planned by Stankov. In this scheme, existing IK-2 parasol fighters were to be modernized by fitting Bf 109B wings and retractable main undercarriage legs. To prove the concept, one damaged IK-2 airframe was rebuilt with stiffener panels to accept the Messerschmitt components.

As envisioned, the concept was to rebuild surviving IK-2s into Messerschmitt-winged IK-2Ms. If successful, Ikarus would restart the IK-2 line to produce new-build IK-6 fighters with DB 601A or Klimove M-105 powerplants. Increasing access to ex-Luftwaffe Bf 109Es put paid to the notion of IK-2 modernizations.

[Vuk]

Astonishing as always, A!  :)

I must mention next, although is not whiff: prior to WWII, Kingdom of Yugoslavia was manufacturing Hawker Hurricanes by license, but was short in engines. However, receiving Messerschmitt Bf 109E, Yugoslavia also received a number of spare engines. Consequently, on one of Hurricanes was installed a Daimler Benz DB.601A. The aircraft received designation LVT-1 (Lovac Vazduhoplovno Tehnički = Fighter Aeronautical Technical; also, the term ''zrakoplovni'' You used is a Croatian term, while in Kingdom of Yugoslavia Serbian term ''vazduhoplovni'' was much more in use). The term Technical supposed to meant that aircraft was to be used as a test example, but it held its 8 x 7,7mm guns, with addition of single 20mm cannon mounted in the engine axis. LVT-1 even saw an action. Five days prior to outbreak of war, it intercepted and forced German Messerschmitt Bf 110 which entered Yugoslav air space to land on April 1st, and on April 8th he attacked a Wehrmacht troops convoy, but without known result. Returning from that mission LVT-1 suffered engine failure and the pilot was forced to land and abandon the aircraft.

[dy031101]

Um...... cool glazed-nose airplanes......  :)

[apophenia]

Thanks guys. And thanks vuk for the correction and details. I knew about the Hurricane with a DB6012 but not the  LVT-1 designation. Cheers!

[arc3371]

Very interesting designs

[JP Vieira]

Very nice designs