1:72 BMW-Hütter Hü 324A-2/R2; "F3+EV", XI./KG210 Deutsche Luftwaffe, Châteaudun, France; April 1946 (Whif/Luft '46/kit bashing)

+++ DISCLAIMER +++

Nothing you see here is real, even though the conversion or the presented background story might be based historical facts. BEWARE!

 

Some background

The Hütter Hü 324 was the final development stage of BMW's 'Schnellbomber II' project, which had been designed around two mighty BMW 109-028 turboprops.

 

These innovative engines had been developed since February 1941, but did not receive fullest attention due to the more promising jet engines. Anyway, it soon became clear that no jet engine with the potential to drive a bomber-sized aircraft - considering both performance and fuel consumption - would be available on short notice. Consequently, the BMW 028 received more attention from the RLM from 1943 on.

 

Biggest pressure came from the fact that several obsolete types like the He 111 or Do 217 had to be replaced, and the ill-fated and complicated He 177 was another candidate with little future potential, since four-engined variants had been rejected. Additionally, the promising and ambitious Ju 288 had been stillborn, and a wide gap for a tactical medium bomber opned in the Luftwaffe arsenal.

 

In may 1943, new requirements for a medium bomber were concretised. Main objective was to design a fast, twin-engined bomber, primarily intended for horizontal bombing, which would be able to carry a 3.000 kilograms (6.600 lbs) payload at 800 kilometres per hour in a 1.500km (900 ml) radius. The plane had to be fast and to operate at great heights, limiting the threat of interception.

 

Since many major design bureaus’ resources were bound, Ulrich W. Hütter, an Austro-German engineer and university professor got involved in the RLM project and BMW's design team which had been working on appropriate designs. In July 1943, Hütter moved to the Research Institute of the Graf Zeppelin works (FGZ) convened in Ruit near Stuttgart, and as head of the engineering department he was also involved in the development of manned missiles, underwater towing systems and the Hü 211 high altitude interceptor/reconnaissance plane.

 

Under Ulrich W. Hütter and his brother, Wolfgang Hütter, BMW's original and highly innovative (if not over-ambitious) Schnellbomber designs gave way to a more conservative layout: the so-called BMW-Hütter Hü 324.

 

The plane was conventional in layout, with high, unswept laminar profile wings and a high twin tail. The engines were carried in nacelles slung directly under the wings. The nose wheel retracted rearwards, while the main wheels retracted forwards into the engine nacelles, rotating 90°, and laying flat under the engines. The crew of four (pilot, co-pilot/bombardier, navigator/radar operator and gunner/radio operator) were accommodated in a compact, pressurised "glass house" cockpit section – a popular design and morale element in Luftwaffe bomber and reconnaissance aircraft of that era.

 

Construction of the first prototype started in February 1945, and while the aircraft cell made good progress towards the hardware stage, the development suffered a serious setback in March when BMW admitted that the 109-028 turboprop engine would not be ready in time. It took until August to arrive, and the prototype did not fly until 6 November 1945.

Initial flight test of the four A-0 pre-production samples of the Hü 324 went surprisingly well. Stability and vibration problems with the aircraft were noted, though. One major problem was that the front glas elements were prone to crack at high speeds, and it took a while to trace the troubole source back to the engines and sort these problems out. Among others, contraprops were fitted to counter the vibration problems, the engines' power output had to be reduced by more than 500 WPS and the tail fins had to be re-designed.

 

Another innovative feature of this bomber was the “Elbegast” ground-looking navigation radar system, which allowed identification of targets on the ground for night and all-weather bombing. It was placed in a shallow radome behind the front wheel. Performance-wise, the system was comparable to the USAAF’s H2X radar, and similarly compact. Overall, the Hü 324 showed much promise and a convincing performance, was easy to build and maintain, and it was immediately taken to service.

 

Despite the relatively high speed and agility for a plane of its size, the Hü 324 bore massive defensive armament: the original equipment of the A-1 variant comprised two remotely operated FDL 131Z turrets in dorsal (just behind the cockpit) and ventral (behind the bomb bay) position with 2× 13 mm MG 131 machine guns each, plus an additional, unmanned tail barbette with a single 20mm canon. All these guns were aimed by the gunner through a sighting station at the rear of the cockpit, effectively covering the rear hemisphere of the bomber.

 

After first operational experience, this defence was beefed up with another remotely-controlled barbette with 2× 13 mm MG 131 machine guns under the cockpit, firing forwards. The reason was similar to the introduction of the chin-mounted gun turret in the B-17G: the plane was rather vulnerable to frontal attacks. In a secondary use, the chin guns could be used for strafing ground targets. This update was at first called /R1, but was later incorporated into series production, under the designation A-2.

 

Effectively, almost 4.500kg ordnance could be carried in- and externally, normally limited to 3.000kg in the bomb bay in order to keep the wings clean and reduce drag, for a high cruising speed. While simple iron bombs and aerial mines were the Hü 324's main payload, provisions were made to carry guided weapons like against small/heavily fortified targets. Several Rüstsätze (accessory packs) were developed, and the aircraft in service received an "/Rx" suffix to their designation, e. g. the R2 Rüstsatz for Fritz X bomb guidance or the R3 set for rocket-propelled Hs 293 bombs.

 

Trials were even carried out with a semi-recessed Fieseler Fi 103 missile, better known as the V1 flying bomb, hung under the bomber's belly and in an enlarged bomb bay, under deletion of the ventral barbette.

 

The Hü 324 bomber proved to be an elusive target for the RAF day and night fighters, especially at height. After initial attacks at low level, where fast fighters like the Hawker Tempest or DH Mosquito night fighters were the biggest threat, tactics were quickly changed. Approaching at great height and speed, bombing was conducted from medium altitudes of 10,000 to 15,000 feet (3,000 to 4,600 m).

 

The Hü 324 proved to be very successful, striking against a variety of targets, including bridges and radar sites along the British coast line, as well as ships on the North Sea.

From medium altitude, the Hü 324 A-2 proved to be a highly accurate bomber – thanks to its "Elbegast" radar system which also allowed the planes to act as pathfinders for older types or fast bombers with less accurate equipment like the Ar 232, Ju 388 or Me 410. Loss rates were far lower than in the early, low-level days, with the Hü 324 stated by the RLM as having the lowest loss rate in the European Theatre of Operations at less than 0.8 %.

 

 

BMW-Hütter Ha 324A-2, general characteristics:

Crew: 4

Length: 18.58 m (60 ft 10 in)

Wingspan: 21.45 m (70 ft 4½ in )

Height: 4.82 m (15 ft 9½ in)

Wing area: 60.80 m² (654.5 ft.²)

Empty weight: 12,890 kg (28,417 lb)

Loaded weight: 18,400 kg (40,565 lb)

Max. take-off weight: 21,200 kg (46,738 lb)

 

Performance:

Maximum speed: 810 km/h (503 mph) at optimum height

Cruising speed: 750 km/h (460 mph) at 10,000 m (32,800 ft)

Range: 3.500 km (2.180 ml)

Service ceiling: 11.400 m (37.500 ft)

Rate of climb: 34.7 m/s (6,820 ft/min)

 

Powerplant:

Two BMW 109-028 ‘Mimir’ turboprop engines, limited to 5.500 WPS (4.044 WkW) each plus an additional residual thrust of 650kg (1.433 lb), driving four-bladed contraprops.

 

Armament:

6× 13mm MG 131 in three FDL 131Z turrets

1× 20mm MG 151/20 in unmanned/remote-controlled tail barbette

Up to 4.500 kg (9.800 lbs) in a large enclosed bomb-bay in the fuselage and/or four underwing hardpoints.

Typically, bomb load was limited to 3.000 kg (6.500 lbs) internally.

 

 

The kit and its assembly

This project/model belongs in the Luft '46 category, but it has no strict real world paradigm - even though Luftwaffe projects like the Ju 288, the BMW Schnellbomber designs or Arado's E560/2 and E560/7 had a clear influence. Actually, “my” Hü 324 design looks pretty much like a He 219 on steroids! Anyway, this project was rather inspired by a ‘click’ when two ideas/elements came together and started forming something new and convincing. This is classic kitbashing, and the major ingredients are:

 

● Fuselage, wings, landing gear and engine nacelles from a Trumpeter Ilyushin Il-28 bomber

● Nose section from an Italeri Ju 188 (donated from a friend, leftover from his Ju 488 project)

● Stabilisers from an Italeri B-25, replacing the Il-28’s swept tail

● Contraprops and fuselage barbettes from a vintage 1:100 scale Tu-20(-95) kit from VEB Plasticart (yes, vintage GDR stuff!)

 

Most interestingly, someone from the Netherlands had a similar idea for a kitbashing some years ago: www.airwar1946.nl/whif/L46-ju588.htm. I found this after I got my idea for the Hü 324 together, though - but its funny to see how some ideas manifest independently?

 

Building the thing went pretty straightforward, even though Trumpeter's Il-28 kit has a rather poor fit. Biggest problem turned out to be the integration of the Ju 188 cockpit section: it lacks 4-5mm in width! That does not sound dramatic, but it took a LOT of putty and internal stabilisation to graft the parts onto the Il-28's fuselage.

 

The cockpit was completely re-equipped with stuff from the scrap box, and the main landing gear received twin wheels.

 

The chin turret was mounted after the fuselage was complete, the frontal defence had been an issue I had been pondering about for a long while. Originally, some fixed guns (just as the Il-28 or Tu-16) had been considered. But when I found an old Matchbox B-17G turret in my scrap box, I was convinced that this piece could do literally the same job in my model, and it was quickly integrated. As a side effect, this arrangement justifies the bulged cockpit bottom well, and it just looks "more dangerous".

 

Another task was the lack of a well for the front wheel, after the Il-28 fuselage had been cut and lacked the original interior. This was also added after the new fuselage had been fitted together, and the new well walls were built with thin polystyrene plates. Not 100% exact and clean, but the arrangement fits the bill and takes the twin front wheel.

 

The bomb bay was left open, since the Trumpeter kit offers a complete interior. I also added four underwing hardpoints for external loads (one pair in- and outboard of the engine nacelles), taken from A-7 Corsair II kits, but left them empty. Visually-guided weapons like the 'Fritz X' bomb or Hs 293 missiles would IMHO hardly make sense during night sorties? I also did not want to overload the kit with more and more distracting details.

 

 

Painting

Even though it is a whif I wanted to incorporate some serious/authentic late WWII Luftwaffe looks. Since the Hü 324 would have been an all-weather bomber, I went for a night bomber livery which was actually used on a He 177 from 2./KG 100, based in France: Black (RLM 22, I simply used Humbrol 33) undersides, and upper surfaces in RLM 76 (Base is Humbrol 128, FS36320, plus some added areas with Testors 2086, the authentic tone which is a tad lighter, but very close) with mottles in RLM 75 (Grauviolett, Testors 2085, plus some splotches of Humbrol 27, Medium Sea Grey), and some weathering through black ink, some enhanced panel lines (with a mix of matte varnish and Panzergrau), as well as some dry painting all over the fuselage.

 

All interior surfaces were painted in RLM 66 (Schwarzgrau/Black Grey, Testors 2079), typical for German late WWII aircraft. Propeller spinners were painted RLM 70 (Schwarzgrün) on the front half, the rear half was painted half black and half white.

 

Pretty simple scheme, but it looks VERY cool, esp. on this sleek aircraft. I am very happy with this decision, and I think that this rather simple livery is less distracting from the fantasy plane itself, making the whif less obvious. In the end, the whole thing looks a bit grey-in-grey, but that spooky touch just adds to the menacing look of this beefy aircraft. I think it would not look as good if it had been kept in daytime RLM 74/75/76 or even RLM 82/83/76?

 

Markings and squadron code were puzzled together from an Authentic Decal aftermarket sheet for a late He 111 and individual letters from TL Modellbau. The "F3" code for the fictional Kampfgruppe (KG) 210 is a random choice, "EV" marks the individual plane, the red "E" and the control letter "V" at the end designate a plane from the eleventh squadron of KG 210. My idea is that the Hü 324 would replace these machines and literally taking their place in the frontline aviaton units. So I tried to keep in line with the German aircraft code, but after all, it's just a whif...

 

 

So, after some more surgical work than expected, the Hü 324 medium bomber is ready to soar!

 

Done