The Hughes Aviation P21-JMK11 Devastator outperformed every combat aircraft in speed, armament, and maneuverability, when it was first released. Although it is now dated, it is still used as a fighter-bomber, where its lack of speed can be overcome by its agility and firepower.
The original Mk I Devastator was a concept model, created by Hughes Aviation, to demontrate the effectiveness of the pusher configuration as applied to combat aircraft. Although lightly armored, the Mk I was a smash success with several key demographics, including state militias.
The Mark II Devastator was a considerable improvement over the Mk I. Key changes included: the change to a significantly more powerful engine, the Allison V-series which would be later used in the Hughes Bloodhawk; the addition of a second pair of linked machine guns; the addition of a fuselage-mounted magnetic missile launcher and the addition of a landing hook, making the Mk II a zeppelin-capable fighter.
These changes made the Mk II the premier zeppelin-escort fighter of the day, and the model was priced accordingly. Mechanics were pleased to discover that the Mk II was much more upgrade-friendly than the sometimes tempermental Mk I. Typical upgrades included adding a supercharger to the engine to increase straight-line speed, fitting a third pair of machine guns to the wings and extending the capacity of the missile magazine.
In 1936, Hughes Aviation released the Mk III Devastator, widely considered an effective fighter but significantly weaker than its predecessor. In a effort to reduce the eye-watering list price of the Mk II, the Mk III was supplied with the Tornado G450 engine, which did not have the nitro-thrust capacity of the Mk II. In order to counter the reduced power, the twin three-bladed counter-rotating propellors of the Mk II were replaced by a single four-bladed propellor. This, in turn, reduces the amounts of force the engine has to exert, but the downside is that removing the counter-rotating props gives the airframe alot more torque to handle, which then contributes to bad maneuverability.
The Mk III also had the magnetic missile launcher removed in favour of standard underwing hardpoints. However, reinforced wing struts allowed a fourth set of guns to be fitted, creating one of the most heavily-armed interceptor-fighters of its day.
While the Mk III was considerably cheaper to purchase and maintain than the Mk II, the Mk II was much more popular, especially among pirate gangs. The Fortune Hunters, long-time fans of the Devastator line, initially deployed in Mk III Devastators, but were able to replace these with classic Mk II models sometime in early 1938.
The Devastator bears some resemblance to the Curtiss-Wright XP-55 Ascender prototype fighter: namely, the pusher engine, canards and vertical stabilisers placed on the wings.
While the majority of aircraft production in North America is for what is anachronistically referred to as "domestic" use, Hughes Aviation followed a different route with the Devastator, making it available internationally. However, the extortionate export duties applied at the order of Hughes himself meant that there was very little interest from his intended customer, the British Empire. However, Hughes was contacted, and eventually supplied hundreds of Devastators to, the USSR. Indeed, the only Hughes plant outside North America is a joint concern with Mikoyan-and-Gurevich near Moscow. This plant is dedicated to the production of the Russian licensed version of the Devastator, which is fundamentally identical to the Mk III.