+++ DISCLAIMER +++
Nothing you see here is real, even though the conversion or the presented background story might be based historical facts. BEWARE!
Some background:
In March 1941 Saab was given the task to design a better fighter than the Seversky Republic P-35s and Reggiane 2000s, at that time the only fighter aircraft Sweden was able or allowed to buy and the air force’s most modern fighters. Several other foreign designs, including the German Bf 109 or even the Japanese Mitsubishi Zero had also been considered.
Anyway, during the ongoing war the procurement of foreign equipment had no predictable future, and so a program for an indigenous fighter aircraft was launched the same year. This resulted in two different designs, which were both initially constructed around an imported German DB 603 engine – a deal which had become possible through the allowance of German transport flights to Norway over Swedish territory, a reason why no Allied equipment was sold to Sweden.
The resulting designs, the L-21 and L-23, differed considerably from each other. The Saab L-21 was a futuristic twin-boom pusher. This unconventional layout was a technological risk, with ejection seat and all, but it was expected to exploit the DB603 engine to the max, with a low-drag airframe (e .g. with a totally buried radiator installation inside of the inner wings) and a well-balanced center of gravity, which was expected to improve handling and turn radius. It was the favored design of Saab’s engineers.
As a fall-back option, though, the L-23 was added. It was a more conservative design with the same DB 603 engine, but with the engine in the classic nose position, a tunnel radiator under the rear fuselage, low tapered wings and a conventional tail. The overall outline resembled the P-51B/C Mustang. Most interestingly, the J 23 was to have a Bofors ejection seat, too, despite its conventional layout.
In December 1941 both designs were approved for prototypes, so that a direct comparison of both layouts could be made. The first of three J 21 prototypes flew on 30 July 1943, while the first three J 23 fighters followed on 10 August, just two weeks later.
Flight tests and evaluation continued until mid-1944 and, despite less weight and size, the J 23 turned out to be fast (Max. speed 626 km/h (388 mph) with the DB 603), but considerably less maneuverable than the J 21, which in itself was also not a perfect aircraft and frequently faced overheating problems.
Faced with two mediocre designs and an urgent need for a modern fighter, it was eventually decided to go ahead with the J 21 for serial production, but a pre-production batch of upgraded J 23 was also ordered for field tests and further development. In the meantime, Sweden had acquired rights to produce the DB 605 in license, and the new fighter was to be adapted to this more modern and powerful engine – it was hoped that the new engine would improve the J 23’s performance, and it was also fitted to the production J 21.
This re-engined variant was the J 23A, of which twelve aircraft were constructed at the main plant in Trollhättan and delivered from August 1945, too late to be involved in typical interception duties at the Swedish borders.
Deliveries of the favored J 21 started in December of the same year. The latter’s field performance turned out to be unsuited for the interceptor role, and the cooling problems persisted. Relegated mainly into the bomber and CAS role (the J 21 turned out to be a passable ground attack aircraft and a stable gun platform), the limitation of the J 21’s pusher design led to a revival of the front-engine J 23.
The resulting J 23B became the aircraft’s actual production variant, incorporating many improvements which had been developed and tested on the prototypes and the pre-production J 23As. These included aerodynamic modifications like a different airfoil on the outer wings and a lowered horizontal stabilizer, coupled with an extended rear fuselage for better directional stability and a slimmed-down radiator fairing for less drag. These machines were delivered from late 1946 on, and a total of forty-six J 23B airframes were produced until early 1948.
In service, the lighter J 23Bs proved to be a better interceptor than the J 21, with a higher top speed and rate of climb, but its handling was less responsive than the pusher aircraft with the same engine and armament.
Overall the J 23B was regarded as inferior to the very similar J 26 (the P-51D) in almost any respect, and the J 23B was never really popular with its flight or ground crews. Consequently, the J 23Bs active fighter career was short and the machines were only operated by the F 16 fighter wing and the F 20 Air Force Academy, both based at Uppsala Airfield, primarily used for advanced weapon and air combat training.
A new evaluation of the J 21 and the J 23 in 1947 led to the decision to retain the J 21 series but to consider the modification of the airframe to accommodate a jet engine. While production line J 21A series aircraft were first selected for conversion, the initial piston-engine version continued in production in five series "batches" that were completed in 1948–49.
Further J 23B production was not resumed, instead the J 26 and J 27 were procured. Anyway, the age of the piston-engine fighter came soon to a close and the Swedish Air Force entered the jet age. Consequently, the J 23B was already phased out, together with the J 21, after 1954.
General characteristics:
Crew: one
Length: 9.58 m (31 ft 4 in)
Wingspan: 11.3 m (37 ft 8 in)
Height: 3.96 (13 ft 0 in)
Wing area: 20.00 m² (215.28 ft²)
Empty weight: 2,535 kg (5,583 lb)
Loaded weight: 3,445 kg (7,588 lb)
Max. take-off weight: 3,663 kg (8,068 lb)
Powerplant:
1× Daimler-Benz liquid-cooled, supercharged, 60° inverted V12 DB 605B engine,
rated at 1,085 kW (1,455 hp / 1,475 PS) and license-built by SFA.
Performance:
Maximum speed: 680 km/h (367 knots, 422 mph)
Cruise speed: 495 km/h (265 knots, 308 mph)
Range: 750 km (466 mi)
Service ceiling: 11,200 m (36,685 ft)
Rate of climb: 17 m/s (3,340 ft/min)
Armament:
1× engine-mounted 20 mm Hispano-Suiza HS.404 or Bofors cannon,
firing through the propeller hub
4× 13 mm Bofors-built Colt machine guns in the outer wings nose
Underwing hardpoints for various bombs, drop tanks and unguided rockets
The kit and its assembly:
The “Swedish Season” continues! The Saab 23 is another “phantom of the past”, a real world design that never left the drawing board. The J 23 actually started as an alternative to the J 21, but was discarded in late 1941 in favor of the more promising, yet bigger and heavier, pusher design. But that would not stop modelers from trying to build one, even though I have never seen a model of this aircraft? Having recently tried to build a Saab 27 fighter caught me in the right mood for another whiffy Swedish design, so I took a chance on the J 23, too.
At first glance you can mistake the J 23 for a P-51B with an engine from a late Bf 109, some sources describe it as “a Swedish Messerschmitt”. But that’s only superficial, much like the later Griffon-powered J 27 project which can be described as a “Super Spitfire”, but this does not do justice to the aircraft’s construction.
Both were independent developments, even though the P-51 (some early specimen were forced to land in Sweden and closely examined) certainly had a massive impact on both designs.
Anyway, the information basis surrounding the J 23 is worse than the J 27’s, and I only had rather vague profile drawings/sketches at hand for reference. A basis model was also hard to find: the rear section from a P-51B (in this case an Intech kit from Poland) was settled, since the Mustang’s cockpit shape, dorsal section and fin come really close to the J 23. But you cannot simply mate a P-51 with a Bf 109 nose, it would result in a rather wacky Mustang-thing because the proportions are not right.
Finding a good solution was not easy, and I was lucky to find a Hasegawa Ki-61 in the stash – it has a German engine (an earlier DB 601, though) and an overall layout similar to the P-51B. But the Ki-61 is considerably larger than a Bf 109, more in the P-51’s size class. Despite many detail modifications I decided to mate these unlikely aircraft for the J 23s basis – engraved panel lines on both kits made the combination less obvious, too.
The InTech P-51B gave its tail and the cockpit section (excluding the radiator tunnel and the wing roots), cut away from the rest of the Mustang fuselage with a Z-shaped cut. With a matching cut on the Ki-61’s fuselage, the engine and the whole wing/fuselage intersection were used. Styrene strips held the fuselage sections in place, on the outside the seams were later blended with nitrous compound putty. One benefit of this solution is that the OOB P-51 canopy could be used (even though the rear end fit necessitated some body work), and the resulting cockpit position was just as far forward as on the J 23, right above the wings. As a consequence the rear fuselage behind the cockpit appears to be rather long, but that is AFAIK correct, the J 23 had these slightly odd proportions!
For the J 23’s DB 605 engine a different, bigger spinner had to be mounted – scratched from a massive PZL 23 spinner and single blades (from the Hasegawa Ki-61), together with a metal axis and a styrene tube adapter inside of the nose. Some putty work was necessary to fair over the Ki-61 guns on the cowling, the typical DB 601 front bulge and blend the bigger, new spinner to the rest of the fuselage, but the result looks O.K.
The Ki-61’s original wings and landing gear could, thanks to the original fuselage section from the Hasegawa kit, be carried over and easily mounted, even though the wing tips were clipped for a square, Mustang-esque shape (the J 23’s look in all illustrations I’ve seen like upscaled Bf 109E wings).
The InTech P-51’s horizontal stabilizers were used, but for a J 23 they had to be placed in a different position: further back (so that wedges for the vertical rudder had to be cut out) and considerably lower, necessitating some (more) body work to hide the original attachment points. The new position adds to the impression of an extended fuselage section behind the cockpit, even though the P-51 donor fuselage section is only a little longer than the Ki-61’s. All tail surface outlines were slightly modified, too.
The J 23’s typical, shallow radiator tunnel had to be scratched, the semi-buried construction sits far behind the wings’ training edge. In an initial step, the removed Ki-61 radiator’s gap as well as the P-51 tail wheel well were faired over with styrene sheet and new intake/outlet ramps integrated into the lower rear fuselage. The tunnel itself is the narrow, aerodynamic fairing of a Boulton Paul Defiant’s machine guns behind the turret (raised when not in use), left over from a Pavla kit, opened at both ends.
As a consequence of the new and long radiator tunnel, the P-51 tail wheel well was moved about 5mm further back and the fuselage profile under the tail fin re-shaped.
One of the final steps was the cockpit interior, because I was not sure concerning the relative position of the P-51’s canopy (cut into three pieces for open display) and dashboard and the Ki-61’s cockpit floor panel and seat. But both turned out to match relatively well, and I added a tank and radio dummy behind the seat in order to prevent a clear view into the rear fuselage.
The landing gear was taken OOB from the Ki-61 – it looks similar to the real J 23 arrangement, so I stuck with it. The tail wheel comes from the InTech P-51, just the covers were scratched for the re-located well.
All gun barrels on spinner and wings are hollow steel needles, no ordnance was hung under the wings, even though the Ki-61 hardpoints were retained. After all, it’s a fighter aircraft.
Painting and markings:
Once more a classic, if not conservative, livery for a fictional aircraft – and in this case I chose the simple olivgrön/ljust blågrå camouflage of the late Fourties, coupled with contemporary color-coded letters identifying the individual aircraft and its squadron within the Flygflöttilj group.
The uniform upper surfaces were painted with RAF Dark Green (Humbrol 163). This tone has an olive drab touch and comes IMHO pretty close to the original Swedish color, the frequently recommended FS 34079 is IMHO too blue-ish. For the underside I used Humbrol 87 (Steel Gray), which is a blue-greenish gray. The authentic tone would be FS 36270, but on a model it appears much too dark, so that the lighter Steel Gray is a handy and individual alternative.
A light black ink was applied in order to emphasize the panel lines, some more depth was added through dry-painted panels with lighter shades of the basic colors (in this case, Humbrol 155 and 128).
The cockpit interior was painted in dark gray (Humbrol 32), while the landing gear and the wells became Aluminum (Humbrol 56).
As an aircraft of the air staff flight, this J 23 received a white spinner and a white code letter on the tail. These and other markings came from various sources and spare decal sheets. Some extra color was added with red warning markings on the wings above the flaps, plus some visual markings - all made with generic decal stripes. The cock nose art is a personal addition - taken from a Spanish Bf 109D, but AFAIK such personal markings were not uncommon on Swedish Air Force aircraft in the post WWII era.
An eye-catcher and some variety on the otherwise simple green/gray livery are white high-viz markings on the wing tips and a wide fuselage band. Such additional markings were frequently used in the post WWII-era during exercises, training or public displays. Styles varied considerably, though, between “color blocks” and wide single bands which I used (seen on a J 21) and even dense, thin zebra stripes on wings and fuselage. In this case, the white markings were painted onto wings and fuselage (Humbrol 34).
Since most panel lines on the fuselage were lost I painted some new ones with a soft pencil. Finally, after some gun soot and exhaust stains made with grinded graphite as well as some dry-brushed silver on the wings’ leading edges and around the cockpit were added, the kit received a coating with matt acrylic varnish.
Another scratch build of an obscure Swedish aircraft that never reached the hardware stage – and pretty successful, IMHO. This sleek J 23 model looks just as harmless and innocent, but involved massive construction work in almost every area as the kitbashed J 27 before. It’s actually the first model rendition of the J 23 I have seen so far – and another funny fact is that this “Swedish Messerschmitt” was built without any Bf 109 part at all!
