+++ DISCLAIMER +++
Nothing you see here is real, even though the conversion or the presented background story might be based on historical facts. BEWARE!
Some background:
After World War I, the German aircraft industry had several problems. German airlines were forbidden to operate multi engine aircraft and during a period all manufacturing of aircraft in Germany was banned. By 1921, some of the restrictions was lifted, civilian aircraft could be made after approval of an international control commission if they fulfilled certain requirements. To bypass these rules and to be able to make whatever aircraft they wanted several aircraft manufacturers moved abroad. In 1921, Carl Bücker handled the purchase of a reconnaissance aircraft from Caspar-Werke in Travemünde. Because they expected problems due to the rules in the peace treaty regarding the export of German fighter aircraft, Bücker explored the possibility to smuggle the parts out of Germany and assemble the aircraft in Sweden.
To make the purchase easier, Ernst Heinkel and Bücker started Svenska Aero in Lidingö in 1921. The contract on the aircraft was transferred from Caspar to Svenska Aero. Heinkel and some German assembly workers temporarily moved to Lidingö to assemble the aircraft. During 1922 to 1923, the company moved into a former shipyard in Skärsätra on Lidingö since the company had received additional orders from the navy's air force. The parts for those aircraft were made in Sweden by Svenska Aero but assembled by TDS. In 1928, the navy ordered four J 4 (Heinkel HD 19) as a fighter with pontoons. That delivery came to be the last licens- built aircraft by Svenska Aero. In the mid-1920s, Svenska Aero created their own design department to be able to make their own aircraft models. Sven Blomberg, earlier employed by Heinkel Flugzeugwerke, was hired as head of design. In 1930, he was joined by Anders Johan Andersson from Messerschmitt. Despite that, Svenska Aero designed and made several different models on their own.
One of them was the model SA-16, a direct response to the Swedish Air Force and Navy’s interest in the new dive bomber tactics, which had become popular in Germany since the mid-Thirties and had spawned several specialized aircraft, the Junkers Ju 87 being the best-known type. The Flygvapnet (Swedish Air Force) had already conducted dive bombing trials with Hawker Hart (B 4) biplanes, but only with mixed results. Diving towards the target simplified the bomb's trajectory and allowed the pilot to keep visual contact throughout the bomb run. This allowed attacks on point targets and ships, which were difficult to attack with conventional level bombers, even en masse. While accuracy was increased through bombing runs at almost vertical dive, the aircraft were not suited for this kind of operations – structurally, and through the way the bombs were dropped.
Therefore, Svenska Aero was tasked to develop an indigenous dedicated dive bomber, primarily intended to attack ships, and with a secondary role as reconnaissance aircraft – a mission profile quite similar to American ship-based “SB” aircraft of the time. Having learnt from the tests with the Hawker Harts, the SA-16 was a very robust monoplane, resulting in an almost archaic look. It was a single-engine all-metal cantilever monoplane with a fixed undercarriage and carried a two-person crew. The main construction material was duralumin, and the external coverings were made of duralumin sheeting, bolts and parts that were required to take heavy stress were made of steel. The wings were of so-called “double-wing” construction, which gave the SA-16 considerable advantage on take-off; even at a shallow angle, large lift forces were created through the airfoil, reducing take-off and landing runs. Retractable perforated air brakes were mounted under the wings’ leading edges. The fully closed “greenhouse cabin” offered space for a crew of two in tandem, with the pilot in front and a navigator/radio operator/observer/gunner behind. To provide the rear-facing machine gun with an increased field of fire, the stabilizers were of limited span but deeper to compensate for the loss of surface, what resulted in unusual proportions. As a side benefit, the short stabilizers had, compared with a wider standard layout, increased structural integrity. Power came from an air-cooled Bristol Mercury XII nine-cylinder radial engine with 880 hp (660 kW), built by Nohab in Sweden.
Internal armament consisted of two fixed forward-firing 8 mm (0.315 in) Flygplanskulspruta Ksp m/22F (M1919 Browning AN/M2) machine guns in the wings outside of the propeller disc. A third machine gun of the same type was available in the rear cockpit on a flexible mount as defensive weapon. A total of 700 kg (1,500 lb) of bombs could be carried externally. On the fuselage centerline, a swing arm could hold bombs of up to 500 kg (1.100 lb) caliber and deploy them outside of the propeller arc when released in a, additional racks under the outer wings could hold bombs of up to 250 kg (550 lb) caliber each or clusters of smaller bombs, e. g. four 50 (110 lb) or six 12 kg (26 ½ lb) bombs.
Flight testing of the first SA-16 prototype began on 14 August 1936. The aircraft could take off in 250 m (820 ft) and climb to 1,875 m (6,152 ft) in eight minutes with a 250 kg (550 lb) bomb load, and its cruising speed was 250 km/h (160 mph). This was less than expected, and pilots also complained that navigation and powerplant instruments were cluttered and not easy to read, especially in combat. To withstand strong forces during a dive, heavy plating, along with brackets riveted to the frame and longeron, was added to the fuselage. Despite this, pilots praised the aircraft's handling qualities and strong airframe. These problems were quickly resolved, but subsequent testing and progress still fell short of the designers’ hopes. With some refinements the machine's speed was increased to 274 km/h (170 mph) at ground level and 319 km/h 319 km/h (198 mph, 172 kn) at 3,650 m (11,980 ft), while maintaining its good handling ability.
Since the Swedish Air Force was in dire need for a dive bomber, the SA-16 was accepted into service as the B 9 – even though it was clear that it was only a stopgap solution on the way to a more capable light bomber with dive attack capabilities. This eventually became the Saab 17, which was initiated in 1938 as a request from the Flygvapnet to replace its fleet of dive bombers of American origin, the B 5 (Northrop A-17), the B 6 (Seversky A8V1) and the obsolete Fokker S 6 (C.Ve) sesquiplane, after the deal with Fokker to procure the two-engine twin-boom G.I as a standardized type failed due to the German invasion of the Netherlands. The B 9 dive bomber would subsequently be replaced by the more modern and capable B 17 in the long run, too, which made its first flight on 18 May 1940 and was introduced to frontline units in March 1942. Until then, 93 SA-16s had been produced between 1937 and 1939. When the B 17 became available, the slow B 9 was quickly retired from the attack role. Plans to upgrade the aircraft with a stronger 14 cylinder engine (a Piaggio P.XIbis R.C.40D with 790 kW/1,060 hp) were not carried out, as it was felt that the design lacked further development potential in an offensive role.
Because the airframes were still young and had a lot of service life ahead of them, most SA-16s were from 1941 on relegated to patrol and reconnaissance missions along the Swedish coastlines, observing ship and aircraft traffic in the Baltic Sea and undertaking rescue missions with droppable life rafts. For long-range missions, the forked ventral swing arm was replaced with a fixed plumbed pylon for an external 682 liters (150 Imp. gal.) auxiliary tank that more than doubled the aircraft’s internal fuel capacity of 582 liters, giving it an endurance of around 8 hours. In many cases, the machine guns on these aircraft were removed to save weight. In this configuration the SA-16 was re-designated S 9 (“S” for Spaning) and the machines served in their naval observation and SAR role well into the Fifties, when the last SA-16s were retired.
General characteristics:
Crew: two, pilot and observer
Length: 9,58 m (31 ft 11 in)
Wingspan: 10,67 m (34 ft 11 in)
Height: 3,82 m (12 ft 6 in)
Wing area: 30.2 m² (325 sq ft)
Empty weight: 2,905 kg (6,404 lb)
Gross weight: 4,245 kg (9,359 lb)
Max takeoff weight: 4,853 kg (10,700 lb)
Powerplant:
1× Bristol Mercury XII nine-cylinder radial engine with 880 hp (660 kW),
driving a three-bladed variable pitch metal propeller
u>Performance:
Maximum speed: 319 km/h (198 mph, 172 kn) at 3,650 m (11,980 ft)
274 km/h (170 mph; 148 kn) at sea level
299 km/h (186 mph; 161 kn) at 2,000 m (6,600 ft)
308 km/h (191 mph; 166 kn) at 5,000 m (16,000 ft)
Stall speed: 110 km/h (68 mph, 59 kn)
Range: 1,260 km (780 mi, 680 nmi)
Service ceiling: 7,300 m (24,000 ft)
Time to altitude: 2,000 m (6,600 ft) in 4 minutes 45 seconds
4,000 m (13,000 ft) in 15 minutes 10 seconds
Armament:
2× fixed 8 mm (0.315 in) Flygplanskulspruta Ksp m/22F (M1919 Browning AN/M2) machine guns
in the wings outside of the propeller disc (with 600 RPG), plus
1× 8 mm (0.315 in) Ksp m/22F machine gun on a flexible mount in the rear cockpit with 800 rounds
Ventral and underwing hardpoints for a total external bomb load of 700 kg (1,500 lb)
The kit and its assembly:
This purely fictional Swedish dive bomber was inspired by reading about Flygvapnet‘s pre-WWII trials with dive bombing tactics and the unsuited aircraft fleet for this task. When I found a Hasegawa SOC Seagull floatplane in The Stash™ and looks at the aircraft’s profile, I thought that it could be converted into a two-seat monoplane – what would require massive changes, though.
However, I liked the SOC’s boxy and rustic look, esp. the fuselage, and from this starting point other ingredients/donors were integrated. Work started with the tail. Originally, I wanted to retain the SOCs fin and stabilizer, but eventually found them oversized for a land-based airplane. In the scrap box I found a leftover fin from an Academy P-47, and it turned out to be a very good, smaller alternative, with the benefit that it visually lengthened the rear fuselage. The stabilizers were replaced with leftover parts from a NOVO Supermarine Attacker – an unlikely choice, but their size was good, they blended well into the overall lines of the aircraft, and they helped to stabilize the fin donor. Blending these new parts into to SOC’s hull required massive PSR, though.
The wings were also not an easy choice, and initially I planned the aircraft with a retractable landing gear. I eventually settled on the outer wings (just outside of the gullwing kink) from an MPM Ju 87 B, because of their shape and the archaic “double wings” that would complement the SOC’s rustic fuselage. However, at this point I refrained from the retractable landing gear and instead went for a fixed spatted alternative, left over from an Airfix Hs 123, which would round up the aircraft’s somewhat vintage look. Because the wheels were missing, I inserted two Matchbox MiG-21 wheels (which were left over in the spares bin from two different kits, though). The tail wheel came from an Academy Fw 190.
Cowling and engine inside (thankfully a 9-cylinder radial that could pose as a Mercury) were taken OOB, just the original two-blade propeller was replaced with a more appropriate three-blade alternative, IIRC from a Hobby Boss Grumman F4F. The cockpit was taken OOB, and I also used the two pilot figures from the kit. The rear crew member just had the head re-positioned to look sideways, and had to have the legs chopped off because there’s hardly and space under the desk with the radio set he’s sitting at.
The ventral 500 kg bomb came from a Matchbox Ju 87, the bomb arms are Fw 189 landing gear parts. Additional underwing pylons came from an Intech P-51, outfitted with 50 kg bombs of uncertain origin (they look as if coming from an old Hasegawa kit). The protruding machine gun barrel fairings on the wings were scratched from styrene rod material, with small holes drilled into them.
A real Frankenstein creation, but it does not look bad or implausible!
Painting and markings:
I gave the B 9 a camouflage that was carried by some Flygvapnet aircraft in the late Thirties, primarily by fighters imported from the United States but also some bombers like the B 3 (Ju 86). The IMHO quite attractive scheme consists on the upper surfaces of greenish-yellow zinc chromate primer (Humbrol 81, FS 33481), on top of which a dense net of fine dark green wriggles (supposed to be FS 34079, but I rather used Humbrol 163, RAF Dark Green, because it is more subdued) was manually applied with a thin brush, so that the primer would still shine through, resulting in a mottled camouflage.
On the real aircraft, this was sealed with a protective clear lacquer to which 5% of the dark green had been added, and I copied this procedure on the model, too, using semi-gloss acrylic varnish with a bit of Revell 46 added. The camouflage was wrapped around the wings’ leading edges and the spatted landing gear was painted with the upper camouflage, too.
The undersides were painted with Humbrol 87 (Steel Grey), to come close to the original blue-grey tone, which is supposed to be FS 35190 on this type of camouflage. The tone is quite dark, almost like RAF PRU Blue.
The interior was painted – using a Saab J 21 cockpit as benchmark – in a dark greenish grey (RAL 7009).
The model received the usual light black ink washing and some post-panel shading on the lower surfaces, because this effect would hardly be recognizable on the highly fragmented upper surface.
The markings are reflecting Flygvapnet’s m/37 regulations, from the direct pre-WWII era when the roundels had turned from black on white to yellow on blue but still lacked the yellow edge around the roundel for more contrast. F6 Västgöta flygflottilj was chosen because it was a dive bomber unit in the late Thirties, and the individual aircraft code (consisting of large white two-digit numbers) was added with the fin and the front of the fuselage. “27” would indicate an aircraft of the unit’s 2nd division, which normally had blue as a standardized color code, incorporated through the blue bands on the spats and the small "2nd div." tag on the rudder (from a contemporary F8 Swedish Gladiator).
Roundels and codes came from an SBS Models sheet, even though they belong to various aircraft types. Everything was finally sealed with matt acrylic varnish.
