Developed in 1918, the Nieuport 31 was a refined derivative of the earlier monoplane prototypes from which it differed configurationally primarily in having an enlarged spanwise auxiliary aerofoil surface. Technically a sesquiplane, but effectively a shoulder-wing monoplane, the Nieuport 31 (also referred to as the Nieuport 31 Rh indicating the engine type) was powered by an 180 hp Le Rhône 9R nine-cylinder rotary and was tested during the course of 1919.

The wing, which was of exceptionally broad chord, incorporated substantial cut-outs at the trailing-edge roots to provide the pilot with a measure of downward view. The auxiliary surface braced beneath the fuselage provided attachment points for the inclined aerofoil-section wing bracing struts. It also enclosed the undercarriage axle and the upper portions of the wheels. The wooden monocoque fuselage was essentially similar to that of the Nieuport 29, and the intended armament consisted of two 0.303 in (7.7 mm) Vickers guns.

Development was abandoned despite excellent performance achieved on comparatively low power, possibly as a result of the rotary engine being, by consensus, passé by this time.
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You can see a more modern aeroplane forming there, nice pic Hauksbee.

Yeah, but...where's the gunz???

It does cry out for some wicked ordnance. It looks like it should be flown by some between-the-wars comics hero like Biggles or Scorchy Smith.

Nieuport was gravitating toward the more powerful, liquid-cooled motors with the Model 29. It was reportedly one hell of a fighter and considered a successor to the Spad, but then again the reports are somewhat sparse because the type never made it to the dogfights of 1918. A "what if" 1919 scenario (like we see sometimes with 'what if 1946') would be an interesting mini-modification for a flight sim. We'd see D.VIIIs, D.VIIs, and advancing German fighters against Sopwith Snipes and Nieuport 29s. Fun stuff to play around with in one's head.

One of the single biggest developments that people often overlook is the incredible growth of power in liquid-cooled engines between 1914 and 1919. The comparative advantage of the rotary is relatively large at 80 hp actually turns to disadvantage at 180 or 200 hp because of the incredible gyroscopic effects the large rotaries could develop. Some builders answered with "counter rotating" rotaries, but with the improvement of the V8 liquid cooled engine by 1919, the rotary's days were numbered. However, you do see some of the principles used in rotraries re-applied to radial engines, which continued on for quite some time alongside the V-type engines.

...and only 10 years later...

I'm sure you all remember the P.B.31E Nighthawk. When Noel Pemberton-Billing sold the company in 1916, there was a young designer on the payroll named Reginald Mitchell. He had no part in designing the P.B.31E Nighthawk, but...(wait for it!) the company was re-named Supermarine. Young Mitchell went on to develop the Schneider Cup racers.

Meanwhile, in Austria-Hungary:



Lloyd's designers are working tirelessly round the clock to create not only the ugliest aircraft in the world, but also the most uncomfortable for pilots to fly.

Did the pilot stand up in that or is it a double decker cockpit LOL

SD

Ugly, they most certainly were, but at least they were groping their way to a workable enclosed cockpit.

edit: Here's another Lloyd offering that I had in a folder. Don't know what the model number is. Notable is the two-story enclosed sections and the one poor devil left out in the breeze. Gunner?

By the way, SirMike1983, I much appreciate your illuminating comments on the inevitability of the rotary's demise.

If only! The pilot was actually sitting behind that monstrous bulge, making it very hard to see and control the machine. The bulge was designed to give the observer a good field of fire without danger of hitting the prop. The Austrian Schwarzlose MG couldn't be made to work well with a synchronizing gear, so all kinds of crazy ideas were tried to solve the problem.

The simplest one was obviously to use Maxims instead.




Fortunately the aircraft was never accepted into service by the Austro-Hungarian air force. I wonder why!

Veering back on topic for a sec., here's the actual Nieuport 29 (now the Nieuport-Delange Type 29) that marked Nieuport's farewell to the rotary. One would never mistake it for a Nieup. The Wikipedia description follows:

The NiD.29 was an equal-span biplane with ailerons on both upper and lower wings. It had a fixed tailskid landing gear, a nose-mounted engine and a single open cockpit for the pilot. The prototype NiD 29 first flew on the 21 August 1918 powered by a Hispano-Suiza 8Fb engine. It performed well in test but could not achieve the required ceiling. The second prototype was modified with an increased wingspan and on achieving the required ceiling it was ordered into production in 1920, becoming the fastest service fighter in the world at that time. Production aircraft did not have ailerons on the upper wing and the lower wing ailerons were increased in size.

The first deliveries were made in 1922 to the French Air Force and the type was popular although it did have a tendency to enter a flat spin. The French military bought 250 aircraft which were built by Nieuport and seven other companies. The Ni-D 29 was to become an important fighter in the 1920s with purchases of 30 by Spain (including 10 Spanish licence built aircraft), 108 by Belgium (87 licensed built by SABCA). The Italian Regia Aeronuatica bought 175 aircraft including 95 built by Macchi as the Macchi-Nieuport 29 and 80 built by Caproni. Sweden bought nine aircraft and designated them J 2. The Japanese company Nakajima bought a pattern aircraft and built 608 for the Imperial Japanese Army as the Ko-4.
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