Engine walkaround vol.26: Hispano-Suiza 8A (type 31)

Subject: Hispano Suiza 8A (Type 31).

Location:Musée d'lair et de l'espace, Le Bourget, Paris, 2015.

Comments: At the beginning of the First World War the production lines of the Barcelona based Hispano-Suiza automobile and engine company were switched to the production of war materiel. Chief engineer Marc Birkigt led work on an aircraft engine based on his successful V8 automobile engine. The resulting engine, called the Hispano-Suiza 8A (HS-31), made its first appearance in February 1915. The first 8A kept the standard configuration of Birkigt's existing design: eight cylinders in 90° Vee configuration, a displacement of 11.76 litres (717.8 cu in) and a power output of 140 hp at 1,900 rpm. In spite of the similarities with the original design, the engine had been substantially refined. The crankshaft was machined from a solid piece of steel. The cylinder blocks were cast aluminium and of. 'mono-block' type that is, in one piece with the SOHC cylinder heads. The inlet and exhaust ports were cast into the blocks, the valve seats were in the top face of the steel cylinder liners, which were screwed into the blocks. Using a rotary driveshaft (tower gear) coming up from the crankcase along the rear end of each cylinder bank, with the final drive for each cylinder bank's camshaft accommodated within a semicircular bulge at the rear end of each valve cover. Aluminium parts were coated in vitreous enamel to reduce leakage. All parts subject to wear, and those critical for engine ignition were duplicated: spark plugs for dual ignition reliability, valve springs, magnetos, etc. Engine reliability and power to weight ratios were major problems in early aviation. The engine and its accessories weighed 185 kg (408 lb), making it 40% lighter than a rotary engine of equivalent power. (Note: This empty weight does not include the radiator and coolant fluid. Generally, air-cooled engines are lighter than their equivalent horsepower water-cooled counterparts. For example, the Bentley BR.2 rotary put out 230 hp (170 kW) and weighed 220 kg (490 lb), Clerget 9B rotary 130 hp (97 kW), 173 kg (381 lb)) The new engine was presented to the French Ministry of War in February 1915, and tested for 15 hours at full power. This was standard procedure for a new engine design to be admitted into military service. However, because of lobbying by French engine manufacturers, the Spanish-made engine was ordered to undergo a bench test that no French-made engine had yet passed: a 50-hour run at full speed. The HS-31 was therefore sent back to Chalais-Meudon on July 21, 1915 and tested for 50 hours, succeeding against all expectations. The design also promised far more development potential than rotary engines which, in spite of being the most common type then in use for aircraft, were getting close to the limits of their development. Rotary engines of increased power generally had increased weight, which in turn increased the already serious gyroscopic torque generated by the engine's rotation. A further increase in torque was considered unacceptable, and the power to weight ratio of the new rotary engines under development did not appeal to aircraft designers. French officials ordered production of the 8A to be started as soon as possible and issued a requirement for a new single-seat high-performance fighter aircraft using the new engine. The Louis Béchereau-designed SPAD VII was the result of this requirement and allowed the Allies to regain air superiority over the Germans.

Engine walkaround vol.25 : BMW132

Subject: BMW132

Location:Musée d'lair et de l'espace, Le Bourget, Paris, 2015.

Comments:BMW took over a license for manufacturing air-cooled radial engines from Pratt & Whitney on 3 January 1928. The nine-cylinder model Pratt & Whitney R-1690 Hornet was initially manufactured virtually unchanged under the designation BMW Hornet. Soon BMW embarked on its own development. The result was the BMW 132 that went into production in 1933, which was essentially an improved version of the Hornet engine. A number of different versions were built. Aside from the carburetor designs used mainly in civilian aircraft, versions with direct fuel injection were manufactured for the German Luftwaffe. The engines had a displacement of 27.7 L (1,690 cu in) and generated up to 960 PS (950 hp; 710 kW) depending on model.The 132 found widespread use in the transport role, remaining the primary powerplant of the Junkers Ju 52 for much of its life, turning the BMW 132 into one of the most important aircraft engines for civilian aircraft during the 1930s.Numerous pioneering flights were undertaken with the BMW 132. The most impressive was the first direct flight from Berlin to New York in a four-engined Focke-Wulf 200 S-1 Condor. It covered the distance to New York in 24 hours and 57 minutes on 10 August 1938.

Engine walkaround vol.24 : Daimler-Benz DB602

Subject: Daimler-Benz DB602 

Location:Musée d'lair et de l'espace, Le Bourget, Paris, 2015.

Comments: The Daimler-Benz DB 602 was a German diesel cycle aero engine designed and built in the early 1930s. It was a liquid-cooled upright V16, and powered the two Hindenburg class airships. It has roughly the same displacement and weight of the Beardmore Tornado, which was used in the ill-fated R101, but has almost twice the power of the Tornado, showing Daimler-Benz's superior knowledge regarding diesel engine construction. Also, these engines, under designation MB 502, powered four Schnellboots of 1933 series S10...13 (three engines on each). Then, the engine was modified into V20 MB 501 of 2000 hp that had a variety of applications.

Engine walkaround vol.23: Hispano-Suiza 12Y

Subject: Hispano-Suiza 12Y

Location: Musée d'lair et de l'espace, Le Bourget, Paris, 2015.

Comments:The Hispano-Suiza 12Y was an aircraft engine produced by Hispano-Suiza for the French Air Force in the pre-WWII period. The 12Y became the primary French 1,000 hp (750 kW) class engine and was used in a number of famous aircraft, including the Morane-Saulnier M.S.406 and Dewoitine D.520. Its design was based on the earlier and somewhat smaller, 12X. A further development was under way, the 12Z, but ended due to the German occupation of France. The 12Y was also produced under Hispano-Suiza licence in the Soviet Union as the Klimov M-100. This design later spawned the highly successful Klimov VK-105series that powered the Yakovlev and Lavochkin fighters as well as the Petlyakov Pe-2 bomber. Licensed production of the early models was also undertaken in Czechoslovakia as the Avia HS 12Ydrs, and in Switzerland as the HS-77. The 12Y was a fairly traditional in construction, a 36-litre water-cooled V-12 with the two cast aluminium cylinder banks set at 60 degrees to each other. The cylinder heads were not removable, instead the entire blockcould be quickly removed from the engine. This made it somewhat famous for being leak-proof, a design feature that was considered by other designers and almost became a part of the Rolls-Royce Merlin. The major design change from the earlier 12X was to use a master-articulated connecting rod system, instead of the fork-and-blade type. A single overhead camshaft (SOHC) drove the valves, which were filled with liquid sodium for cooling. Only a single intake and exhaust valve were used, unlike most designs of the era which had moved to three or four valves per cylinder. A single-stage, single-speed supercharger was standard, although the art of designing a useful intake was not as well developed as in other countries, and high altitude performance was always lacking.

Engine walkaround vol.22: Pratt & Whitney YF119 jet engine

Subject: Pratt & Whitney YF119 jet engine

Location: USAF Museum, Dayton, Ohio, USA, 2014

Comments: The Pratt & Whitney F119 (company designation PW5000) is an afterburning turbofan engine developed by Pratt & Whitney for the Lockheed Martin F-22 Raptor advanced tactical fighter. The engine delivers thrust in the 35,000 lbf (160 kN) class, and is designed for supersonic flight without the use of afterburner (supercruise). Delivering almost 22% more thrust with 40% fewer parts than conventional, fourth-generation military aircraft engine models, the F119 allows sustained supercruise speeds of up to Mach 1.8. The F119's nozzles incorporate 2D thrust vectoring technology. These nozzles direct the engine thrust ±20° in the pitch axis to give the F-22 enhanced maneuverability.

Engine walkaround vol.21: Allison V1710 engine for the Bell P39Q Airacobra

Subject: Allison V1710 for the P39Q Airacobra

Location: USAF Museum, Dayton, Ohio, USA, 2014
Comments: The P-39 was an all-metal, low-wing, single-engine fighter, with a tricycle undercarriage and an Allison V-1710 liquid-cooled V-12 engine mounted in the central fuselage, directly behind the cockpit.The Airacobra was one of the first production fighters to be conceived as a "weapons system"; in this case the aircraft (known originally as the Bell Model 4) was designed around the 37 mm T9 cannon. This weapon, which was designed in 1934 by the American Armament Corporation, a division of Oldsmobile, fired a 1.3 lb (610 g) projectile capable of piercing .8 in (2 cm) of armor at 500 yd (450 m) with armor-piercing rounds. The 200 lb, 90-inch-long weapon had to be rigidly mounted and fire parallel to and close to the centerline of the new fighter. It would be impossible to mount the weapon in the fuselage, firing through the cylinder banks of the Vee-configured engine and the propeller hub as could be done with smaller 20mm cannon. Weight, balance and visibility problems meant that the cockpit could not be placed farther back in the fuselage, behind the engine and cannon. The solution adopted was to mount the cannon in the forward fuselage and the engine in the center fuselage, directly behind the pilot's seat. The tractor propeller was driven via a 10-foot-long (3.0 m) drive shaft which was made in two sections, incorporating a self-aligning bearing to accommodate fuselage deflection during violent maneuvers. This shaft ran through a tunnel in the cockpit floor and was connected to a gearbox in the nose of the fuselage which, in turn, drove the three- or (later) four-bladed propeller via a short central shaft. The gearbox was provided with its own lubrication system, separate from the engine; in later versions of the Airacobra the gearbox was provided with some armor protection. The glycol-cooled radiator was fitted in the wing center section, immediately beneath the engine; this was flanked on either side by a single drum shaped oil cooler. Air for the radiator and oil coolers was drawn in through intakes in both wing-root leading edges and was directed via four ducts to the radiator faces. The air was then exhausted through three controllable hinged flaps near the trailing edge of the center section. Air for the carburetor was drawn in via a raised oval intake immediately aft of the rear canopy.

Ref: Wikipedia( https://en.wikipedia.org/wiki/Bell_P-39_Airacobra#/media/File:Bell_P-39_Airacobra_center_fuselage_detail.jpg )

Engine walkaround vol.20: Allison V1710

Subject: Allison V1710

Location: USAF Museum, Dayton, Ohio, USA, 2014; Fantasy of flight museum, Florida, USA, 2013

Comments: The Allison V-1710 aircraft engine was the only indigenous US-developed V-12 liquid-cooled engine to see service during World War II. Versions with a turbocharger gave excellent performance at high altitude in the twin-engined Lockheed P-38 Lightning, and turbosuperchargers were fitted to experimental single-engined fighters with similar results. The United States Army Air Corps (USAAC) preference for turbochargers early in the V-1710's development program meant that less effort was spent on developing suitable mechanically-driven, centrifugal superchargers for the Allison V-12 design, as other V-12 designs from friendly nations like the British Rolls-Royce Merlin were already using. When smaller-dimensioned or lower-cost versions of the V-1710 were desired, they generally had poor performance at higher altitudes. The V-1710 nevertheless gave excellent service when turbocharged, notably in the P-38 Lightning, which accounted for much of the extensive production run.

Engine walkaround vol.19.: Napier Sabre IIA fighter engine

Subject: Napier Sabre IIA fighter engine

Location: Air and Space Museum, Le Bourget, France 2015 

Comments:The Napier Sabre was a British H-24-cylinder, liquid-cooled, sleeve valve, piston aero engine, designed by Major Frank Halford and built by Napier & Son during World War II. The engine evolved to become one of the most powerful inline piston aircraft engines in the world, developing from 2,200 horsepower (1,640 kW) in its earlier versions to 3,500 hp (2,600 kW) in late-model prototypes. The first operational aircraft to be powered by the Sabre were the Hawker Typhoon and Hawker Tempest; the first aircraft powered by the Sabre was the Napier-Heston Racer, which was designed to capture the world speed record. Other aircraft using the Sabre were early prototype and production variants of the Blackburn Firebrand, the Martin-Baker MB 3 prototype and a Hawker Fury prototype. The rapid introduction of jet engines after the war led to the quick demise of the Sabre, as there was less need for high power military piston aero engines and because Napier turned its attention to developing turboprop engines such as the Naiad and Eland. Prior to the Sabre, Napier had been working on large aero engines for some time. Their most famous was the Lion, which had been a very successful engine between the World Wars and in modified form had powered several of the Supermarine Schneider Trophy competitors in 1923 and 1927, as well as several land speed record cars. By the late 1920s, the Lion was no longer competitive and work started on replacements. Napier followed the Lion with two new H-block designs: the H-16 (Rapier) and the H-24 (Dagger). The H-block has a compact layout, consisting of two horizontally opposed engines, lying one atop or beside another. Since the cylinders are opposed, the motion in one is balanced by the motion on the opposing side, leading to no first order vibration or second order vibration. In these new designs, Napier chose air cooling but in service, the rear cylinders proved to be impossible to cool properly, which made the engines unreliable.Halford started work with Napier, using the Dagger as the basis. The layout of the H-block, with its inherent balance and the Sabre's relatively short stroke, allowed it to run at a higher rate of rotation, to deliver more power from a smaller displacement, provided that good volumetric efficiency could be maintained (with better breathing), which sleeve valves could do. Another important effect of increasing the number of cylinders was that the piston area increases (for a given capacity and bore/stroke ratio) and this brings higher power. Problems arose as soon as mass production began. Prototype engines had been hand-assembled by Napier craftsmen and it proved to be difficult to adapt it to assembly-line production techniques. The sleeves often failed, leading to seized cylinders, which caused the loss of the sole prototype Martin-Baker MB 3. After testing some 18 different materials and manufacturing techniques, a process of nitriding and lapping the sleeves helped resolve the problem. Quality control proved to be inadequate, engines were often delivered with improperly cleaned castings, broken piston rings and machine cuttings left inside the engine. Mechanics were overworked trying to keep the Sabres running and during cold weather they had to run them every two hours during the night so that the engine oil would not congeal and prevent the engine from starting the next day. These problems took too long to remedy and the engine gained a bad reputation. By 1944, the Sabre V was delivering 2,400 horsepower (1,800 kW) consistently and the reputation of the engine started to improve. This was the last version to enter service, being used in the Hawker Typhoon and its derivative, the Hawker Tempest. Without the advanced supercharger, the engine's performance over 20,000 ft (6,100 m) fell off rapidly and pilots flying Sabre-powered aircraft, were generally instructed to enter dogfights only below this altitude. At low altitude, both planes were formidable, with the Typhoon readily outperforming its German counterpart, the FW 190. After the destruction of the Luftwaffe during early 1944, Typhoons were increasingly used as fighter-bombers, notably by the RAF Second Tactical Air Force. The Tempest became the principal destroyer of the V-1 flying bomb (Fieseler Fi 103), since it was the fastest of all the Allied fighters at low levels. Later on, the Tempest was responsible for the destruction of about 20 Messerschmitt Me 262 jet aircraft. Development continued and the later Sabre VII delivered 3,500 hp (2,600 kW) with a new supercharger. The final test engines delivered 5,500 hp (4,100 kW) at 45 lb/in² boost. By the end of World War II, there were several engines in the same power class. ThePratt & Whitney R-4360 Wasp Major four-row, 28-cylinder radial produced 3,000 hp (2,280 kW) at first and later types produced 3,800 hp (2,834 kW), but these required almost twice the displacement in order to do so, 4,360 cubic inches (71 litres). (ref: Wikipedia)

Engine Walkaround vol.18: BMW 801

Subject: BMW 801 radial engine
Location: Air and Space Museum, Le Bourget, France 2015; Deutches Museum, Munich, Germany, 2013.

Comments:The BMW 801 was a powerful German air-cooled 14-cylinder-radial aircraft engine built by BMW and used in a number of German Luftwaffe aircraft of World War II. Production versions of the twin-row engine generated between 1,560 and 2,000 PS (1,540-1,970 hp, or 1,150-1,470 kW). It was the most produced radial engine of Germany in World War II with more than 28,000 built. The 801 was originally intended to replace existing radial types in German transport and utility aircraft. At the time, it was widely agreed among European designers that an inline engine was a requirement for high performance designs due to its smaller frontal area and resulting lower drag. Kurt Tank successfully fitted a BMW 801 to a new fighter design he was working on, and as a result the 801 became best known as the power plant for the famous Focke-Wulf Fw 190.The 801 was a radial engine with two rows of seven cylinders.The cylinders had both bore and stroke of 156 millimetres (6.1 in), giving a total capacity of 41.8 litres (2,550 cu in), just a bit less than the American Wright Cyclone 14 twin-row radial of some 1,600 to 1,900 hp output. The unit (including mounts) weighed from 1,010 to 1,250 kg and was about 1.29 m (51 in) across, depending on the model.The BMW 801 was cooled by forced air from a magnesium alloy cooling fan, 10 bladed in the initial models, but 12 bladed in most engines. The fan rotated at 1.72 times the crankshaft speed (3.17 times the propeller speed). Air from the fan was blown into the center of the engine in front of the propeller gearing housing, and the shape of the housing and the engine itself carried the air to the outside of the cowling and across the cylinders. A set of slots or gills at the rear of the cowling allowed the hot air to escape. This provided effective cooling although at the cost of about 70 PS (69 hp, 51.5 kW) required to drive the fan when the aircraft was at low speed. Above 170 miles per hour (270 km/h), the fan absorbed little power directly as the vacuum effect of the airflow past the air exits provided the needed flow.