I would like to propose very interesting experimental construction of Aichi S1A Denko.
Why very interesting?
1. First IJN A/C designed as Night Fighter;
2. Mounted radar (very rare in Japanese A/C's in WWII era);
3. Powerfull armament;
4. Remote controled dorsal turret for use not in self-defence but in 'Schräge Musik' ('Jazz Music') tactic! (Elevation angle up to 30 degrees from horizontal position. I couldn't find informations about the angle of turret rotation.)
Turret used in this technique enabled aiming without the need to change of flight direction of aircraft.
Specifications (from Wikipedia):
General characteristics
Crew: 2
Length: 49 ft 6.5 in (15.100 m)
Wingspan: 57 ft 5 in (17.50 m)
Height: 15 ft 1.5 in (4.610 m)
Wing area: 505.902 sq ft (46.9998 m2)
Empty weight: 16,138 lb (7,320 kg)
Gross weight: 22,443 lb (10,180 kg)
Max takeoff weight: 25,375 lb (11,510 kg)
Powerplant: 2 × Nakajima NK9K-S , 2,000 hp (1,500 kW) each at take-off
Propellers: 4-bladed
Performance
Maximum speed: 360 mph (579 km/h; 313 kn)
Cruise speed: 273 mph (237 kn; 439 km/h)
Range: 1,054 mi (916 nmi; 1,696 km)
Ferry range: 1,553 mi (1,350 nmi; 2,499 km)
Service ceiling: 39,370 ft (12,000 m)
Wing loading: 44.4 lb/sq ft (217 kg/m²)
Armament
Guns:
2× fuselage-mounted forward-firing 30mm Type 5 cannon
2× fuselage-mounted forward-firing 20mm Type 99 model 1 cannon
2× dorsal turret-mounted 20mm Type 99 model 2 cannon
In other sources (in Polish - unfortunately without pictures but with usefull technical informations
http://menstream.pl/lotnictwo/aichi/aichi;s1a;denko,1079.html) there are informations about:
1) Planning of use more powerfull engine Nakajima NK9K-L "Homare" 24 with turbocharger. This change would allow to reach 679 km/h at 6000m altitude!
2) Bomb load up to 500 kg (including 4x 60kg phosphorous bombs to dispersing the formation of enemy bombers).
Other links:
http://en.wikipedia.org/wiki/Aichi_S1Ahttp://www.daveswarbirds.com/Nippon/aircraft/Denko.htmhttp://japaneseaircraft.devhub.com/blog/521597-aichi-s1a1-denko/http://www.aviastar.org/air/japan/aichi_s1a.phphttp://airjap.free.fr/avions/chasseurs/janvier/Denko.html (French)
http://warfiles.ru/show-17860-opytnyy-tyazhelyy-dvuhmotornyy-nochnoy-istrebitel-s1a-aichi-s1a-denko-yaponiya.html or
http://alternathistory.org.ua/opytnyi-tyazhelyi-dvukhmotornyi-nochnoi-istrebitel-s1a-aichi-s1a-denko-yaponiya (Russian - great drawings!)
http://pro-samolet.ru/samolet-japan/samoleti-imperatorskogo-flota/80-notschnie-istrebiteli/328-japan-istrebitel-aichi-s1a-denko (Russian)
http://www.airwar.ru/enc/fww2/s1a.html (Russian - different data about used engines and reached speed)
Interesting aircraft, isn't it?