Ki-48-IIb and Ki-66 Dive Bombers

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The Ki-48 was a twin-engined bomber designed in the late 1930s that saw much service during the initial Japanese invasions of SE Asia during the outset of WW2. In its initial configuration (Ki-48-I) it was found to be a bit too slow and vulnerable to fend off Allied fighter attacks as it was poorly armed with small machine guns and lacked sufficient armor.  It was however a step up from earlier light bombers of the interwar period such as the Ki-32, being faster, able to fly higher, and with a better range and bomb payload. Still, the Ki-48 at its outset was a target for Allied fighters and benefited from upgrades added in later versions.

Among those versions were a few models that are worth taking note of and adding to games, the Ki-48 IIa, IIb, IIc and the Ki-66 variant. Of course the original Ki-48-I could also be added at a lower tier. Note that the Ki-66 below is a sort of logical upgrade of the Ki-48 model and is a good choice for game developers who want to re-use the basic Ki-48 model on something noticeably different. Overall it was a successful aircraft and survived well into the Pacific War.

1. Ki-48-IIa, IIb and IIc

As compared to the Ki-48-I models before it the Ki-48-IIa incorporated a slightly lengthened fuselage, improved engines (Nakajima Ha-115s with a two-stage blower), some fuel-tank protection, and additional armor for the crew, including a 12.5mm armor plate behind the bombardier’s seat, a 6.5mm plate under the pilot’s seat, 16.5mm armour behind the pilot’s seat, and 16.5mm plates to protect the dorsal and ventral ammunition boxes. These were all welcome additions that gave the Ki-48 design improved survivability. The maximum bomb-load of the Ki-48-II was double that of the -I, and its speed was superior to that of the -I. The 7.7mm machine guns remained weak defensive armament, however.

Unlike other Ki-48 models that were traditional bombers, the Ki-48-IIb was a dive bomber version of the Ki-48-IIa, fitted with retractable dive brakes under the outer wings. The fuselage was also further reinforced.

The final production variant, the Ki-48-IIc, received a larger 12.7mm machine gun in a flexible dorsal mounting, plus a second nose-mounted 7.7mm machine gun; the bombardier could use either gun as needed.

The Ki-48-II variants continued as bombers until late into the war, over 5 years after the Ki-48 was first introduced in 1940, quite an accomplishment when the design year of 1937 is taken into account.

Crew: Four
Length: 12.75 m (41 ft 9 in)
Wingspan: 17.45 m (57 ft 3 in)
Height: 3.8 m (12 ft 5 in)
Wing area: 40 m² (430.555 ft²)
Empty weight: 4,550 kg (10,031 lb)
Loaded weight: 6,500 kg (14,350 lb)
Max. takeoff weight: 6,750 kg (14,881 lb)
Powerplant: 2 × Nakajima Ha.115 radial engines, 843 kW (1,130 hp) each
Performance
Maximum speed: 505 km/h (273 kn, 314 mph) at 5,600 m (18,375 ft)
Range: 2,400 km (1,296 nmi, 1,491 mi)
Service ceiling: 10,100 m (33,135 ft)
Armament
3 × 7.7 mm (0.303 in) Type 89 machine guns, in nose, dorsal and ventral positions
800 kg (1,764 lb) of bombs

ki-48

2. Ki-66

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The Ki-66 is a relatively unknown group of 6 finished prototypes designed by Takeo Doi that took the basic Ki-48-II design and sought to improve it considerably as a new model dive bomber and ground assault plane. It was better streamlined than the Ki-48 it was based on and incorporated some characteristics of the Ki-45 Heavy Fighter, also designed by Kawasaki. While it was a very different sort of aircraft than the German Stukas, it was an attempt to replicate the successes of the Stuka raids over Europe at the request of the Army. It incorporated new dive brakes and two fixed, forward-firing 12.7mm machine guns in the nose, replacing the glazed turret there for a more aerodynamic solid nose. Overall the design was less bulbous than the Ki-48, with a shorter length and narrower wingspan, and it seated two rather than four.

The Ki-66 with its original Army Type1 (Nakajima Ha-115) 14 cylinder air cooled radials from the Ki-48-II was capable of reaching somewhat higher speeds than the Ki-48-II which notably already roughly doubled that of the inspiration for the Ki-66, the Stukas, which had a maximum speed of only 193 mph versus 332 mph for the Ki-66. In the end, however, the speed improvement of only slightly less than 20mph over the Ki-48-II was not significant enough to impress the Army. A problem with the Ki-48 was that it required fighter escorts, and the Army of course would have preferred for the Ki-66 to be able to fly fast enough that it could perform missions without escort.

In the end the enhancements to the Ki-66 over its predecessor were deemed not enough to justify the new model, and it was not selected for mass-production. The Ki-66-Ib, powered by two 1,360hp Nakajima Ha-315-I radials was completed by modifying one of the existing prototypes, but the speed difference there again must not have been significant. Plans to further improve the installed engines with a pair of 2,100hp Nakajima Ha-39 (the Ki-66-Ic ) and 1,900hp Nakajima Ha-45 engines (the Ki-66-Id), were proposed but never built. Before Kawasaki could prove the project was worth saving and more powerful engines were fitted, the project was scrapped. The project was not a total loss, however, as some enhancements made their way back to the Ki-48 line, including the dive brakes which were implemented on the Ki-48-IIb mentioned above.

The forward firing guns would have changed the Ki-66’s role rather considerably, allowing for strafing attacks on ground targets, but it also did so with a reduced bomb load. The Army already had Kawasaki’s own Ki-45 line of heavy fighters which were capable of ground attack, so when the Ki-66-II design as a heavy fighter was proposed, it was also rejected.

For games, the Ki-66 offers a less bulky version of the Ki-48-II with forward firing guns and a slightly improved top speed. The nose-mounted guns make this more of an “assault” plane than the standard Ki-48, and more playable and versatile for games where planes are controlled by a single player, such as in War Thunder. Being able to offensively fire from the cockpit view while controlling the flight of the aircraft is preferable in such FPS games.

The Ki-66, note the solid nose where machine guns and a light were mounted:

Ki-66

Crew: 2

Engine: Two Army Type1 (Nakajima Ha-115) 14 cylinder air cooled radials

Power: 1,130 at take off, 1,100hp at 9,350ft, 940hp at 18,370ft
Wing span: 50ft 10 ¼ in
Length: 36ft 8 15/16in
Height: 12ft 1 21/32in
Empty Weight: 9,039lb
Loaded Weight: 12,677lb
Max Speed: 332mph at 18,370ft
Service Ceiling: 32,810ft
Range: 1,243 miles
Armament: Two fixed forward firing 12.7mm machine guns, two flexibly mounted rear firing 7.7mm machine guns, one dorsal and one ventral
Bomb-load: 661lb normal, 1,102lb maximum

Notice the resemblance of the Ki-66 to some other Kawasaki twin engine planes such as the Ki-45 and Ki-102.

ki-66b

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