Author Archives: William Pearce

Dutheil Chalmers Eole props rear

Dutheil-Chalmers Éole Opposed-Piston Aircraft Engine

By William Pearce

In 1906, the French company Société L. Dutheil, R. Chalmers et Cie (Dutheil-Chalmers) began developing aircraft engines for early aviation pioneers. The company was headquartered in Seine, France and was founded by Louis Dutheil and Robert-Arthur Chalmers. Although most of their engines were water cooled, the Dutheil-Chalmers’ horizontal aviation engines may have been the first successful versions of the horizontal type that is now used ubiquitously in light aircraft. Continuing to innovate for the new field of aviation, Dutheil-Chalmers soon developed a line of horizontal, opposed-piston engines.

Dutheil Chalmers Eole patent

Taken from the Dutheil-Chalmers British patent of 1909, this drawing shows the layout of the horizontal, opposed-piston engine. The dashed lines represent the bevel-gear cross shaft that synchronized the two crankshafts.

On 23 November 1908, Dutheil-Chalmers applied for a French patent 396,613 that outlined their concept of an opposed-piston engine, as well as other engine types. The French patent is referenced in British patent 26,549, which was applied for on 16 November 1909 and granted on 21 July 1910. In the British patent, Dutheil-Chalmers stated that the engine would have two crankshafts. The output shaft would not be a power shaft that connected the two crankshafts. Rather, the crankshafts would rotate in opposite directions (counter-rotating), and a propeller would mount directly to each crankshaft. This is the same power transfer method used in the SPA-Faccioli opposed-piston aircraft engines. While the Dutheil-Chalmers and SPA-Faccioli engines shared a similar concept and were built and developed at the same time, there is no indication that either company copied the other.

The Dutheil-Chalmers opposed-piston engines are sometimes referred to as Éole engines. It is not clear if Dutheil-Chalmers marketed the engines for a time under a different name or if Éole was just the name they gave to their line of opposed-piston engines. Éole is the French name for Aeolus, the ruler of the winds in Greek mythology. The engines were primarily intended to power airships. The two counter-rotating propellers would cancel out the torque associated with a single propeller on a standard engine. In addition, the opposed-piston engine’s two-propeller design did not require the heavy and cumbersome shafting and gears necessary for a conventional single-crankshaft engine to power two propellers.

Dutheil Chalmers Eole 2 view

Top and side view drawings of the four-cylinder, opposed-piston engine. The drawings show no valve train and differ slightly from photos of the actual engine, but they give an idea of the engine’s general layout.

Four different horizontal, opposed-piston engine sizes were announced, all of which were water-cooled. Three of the engines had the same bore and stroke but differed in the number of cylinders used. These engines had two, three, and four cylinders. Each had a 4.33 in (110 mm) bore and a 5.91 in (150 mm) stroke, which was an 11.81 in (300 mm) stroke equivalent with the two pistons per cylinder. The two-cylinder engine displaced 348 cu in (5.7 L) and produced 38 hp (28 kW) at 1,000 rpm. The engine weighed 220 lb (100 kg). The three-cylinder engine displaced 522 cu in (8.6 L) and produced 56 hp (42 kW) at 1,000 rpm. The engine weighed 397 lb (180 kg). The four-cylinder engine displaced 696 cu in (11.4 L) and produced 75 hp (56 kW) at 1,000 rpm. The engine weighed 529 lb (240 kg). It is not clear if any of these engines were built.

The fourth engine was built, and it was the largest opposed-piston engine in the Dutheil-Chalmers line. The bore was enlarged to 4.92 in (125 mm), and the stroke remained the same at 5.91 in (150 mm)—an 11.81 in (300 mm) equivalent with the two pistons per cylinder. The four-cylinder engine displaced 899 cu in (14.7 L) and produced 97 hp (72 kW) at 1,000 rpm. Often, the engine is listed as producing 100 hp (75 kW). The four-cylinder engine weighed 794 lb (360 kg).

Dutheil Chalmers Eole front

This Drawing illustrates the front of the Dutheil-Chalmers opposed-piston engine. Note the cross shaft that synchronized the two crankshafts. The gear on the cross shaft drove the engine’s camshaft. The pushrods, rockers, and valves are visible.

Only the 97 hp (72 kW) engine was exhibited, but it was not seen until 1910. The engine was displayed at the Paris Flight Salon, which occurred in October 1910. The engine consisted of four individual cylinders made from cast iron. The horizontal cylinders were attached to crankcases on the left and right. Threaded rods secured the crankcases together and squeezed the cylinders between the crankcases. Each crankcase housed a crankshaft, and the two crankshafts were synchronized by a bevel-gear cross shaft positioned at the front of the engine. A two-blade propeller was attached to each crankshaft. The propellers were phased so that when one was in the horizontal position, the other was in the vertical position.

Near the center of the cross shaft was a gear that drove the camshaft, which was positioned under the engine. The camshaft actuated pushrods for the intake valves on the lower side of the engine and the exhaust valves on the upper side of the engine. The pushrods of the intake valves travel between the cylinders. All of the pushrods acted on rocker arms that actuated the valves positioned in the middle of the cylinder. Each cylinder had one intake and one exhaust valve.

No information has been found that indicates any Dutheil-Chalmers Éole opposed-piston engines were used in any airship or aircraft. Still, it is an unusual engine conceived and built at a time of great innovation, not just in aviation, but in all technical fields.

Dutheil Chalmers Eole props rear

The 97 hp (72 kW), four-cylinder, eight-piston engine on display at the Paris Flight Salon in 1910. The engine has appeared in various publications as both a Dutheil-Chalmers and an Éole. Note the rods that secured the crankcases together. What appears to be the camshaft can be seen under the engine.

Sources:
Les Moteurs a Pistons Aeronautiques Francais Tome II by Alfred Bodemer and Robert Laugier (1987)
“Improvements in or connected with Motors especially applicable to Aviation and Aerostation Purposes” GB patent 26,549 by L. Dutheil, R. Chalmers and Company (granted 21 July 1910)
“Motors for Aerial Navigation—V” by J. S. Critchley, The Horseless Age (26 October 1910)
“Aerial Motors at the Salon” by Oiseau, Flight (5 November 1910)

SPA-Faccioli N3 rear

SPA-Faccioli Opposed-Piston Aircraft Engines

By William Pearce

Aristide Faccioli was an Italian engineer. In the late 1800s, he became fascinated with aviation and worked to unravel the mysteries of powered flight. With little progress in aviation, Aristide had turned to automobile development by 1898. He worked for Ceirano GB & C and designed Italy’s first automobile, the Welleyes. Ceirano GB & C did not have the finances to produce the automobile, so a new company was established for automobile production. This company was called Fabbrica Italiana Automobili Torino or FIAT, and it bought the rights, plans, and patents for the Welleyes. The Welleyes became FIAT’s first production automobile, the 3 ½ CV.

SPA-Faccioli N1

The SPA-Faccioli N.1 engine with its four cylinders, each housing two opposed pistons. At the rear of the engine (bottom of image) is the cross shaft linking the two crankshafts. Note the gear on the cross shaft that drove the camshaft.

Aristide became FIAT’s first technical director, but he left in 1901 to start his own automobile company. In 1905, Aristide moved from automobile production to engine design. However, Aristide’s focus returned to aviation once he learned of the successful flights of the Wright Brothers and other early pioneers. In 1907, Aristide shut down his companies and worked on aircraft and aircraft engine designs. In 1908, Aristide visited a close friend, Matteo Ceirano, seeking financial support. Matteo was one of Ceirano GB & C’s founders and was a co-founder of SPA (Società Ligure Piemontese Automobili). Matteo and SPA backed Aristide and encouraged him to continue his aeronautical work.

Aristide’s first engine was the SPA-Faccioli N.1. The N.1 was a water-cooled, horizontal, opposed-piston engine. Each side of the engine had a crankshaft that drove pistons in the engine’s four, individual cylinders. Attached to each crankshaft was a propeller. The crankshafts and their propellers turned in opposite directions (counter-rotating). When viewed from the rear of the engine, the right propeller turned clockwise, and the left propeller turned counterclockwise. The two-blade, wooden propellers were phased so that when one was horizontal the other was vertical. The dual, counter-rotating propeller design was an effort to eliminate engine vibrations and cancel out propeller torque.

SPA-Faccioli N2

This rear view of the SPA-Faccioli N.2 illustrates that the engine was much more refined than the N.1. Note the magneto driven above the cross shaft and the gear train driven below.

The two crankshafts were synchronized by a bevel-gear cross shaft that ran along the rear of the engine. Geared to the cross shaft was a camshaft that ran under the engine. The camshaft actuated the intake and exhaust valves that were located in the middle of each cylinder. As the two pistons in each cylinder came together, the air/fuel mixture was compressed. Once the mixture was ignited by the spark plug in the middle of the cylinder, the expanding gasses pushed the pistons back, operating like any other four-stroke engine. The N.1 had a 4.41 in (112 mm) bore and a 5.91 in (150 mm) stroke. The two pistons per cylinder effectively gave the N.1 an 11.81 in (300 mm) stroke. The engine displaced 721 cu in (11.82 L) and produced 80 hp (60 kW) at 1,200 rpm. The N.1 weighed 529 lb (240 kg).

The N.1 engine was installed in the Faccioli N.1 aircraft, which was a triplane pusher design. Flown by Mario Faccioli, Aristide’s son, the engine, aircraft, and pilot all made their first flight on 13 January 1909. The aircraft quickly got away from Mario, and the subsequent crash injured Mario and destroyed the aircraft. Although brief, the flight marked the first time an Italian-designed and built aircraft was flown with an Italian-designed and built engine. With all parties undeterred, the N.1 engine was installed in the Faccioli N.2 aircraft (a biplane pusher with a front-mounted elevator) and flown by Mario in June 1909. After a few flights, Mario and the N.2 aircraft were involved in an accident that again injured Mario and destroyed the aircraft.

Faccioli N3 aircraft

Mario Faccioli sits on the Faccioli N.3 aircraft in 1910. Note the covers over the N.2 engine’s cross shaft bevel gears. Since the propellers rotated in opposite directions, when one was vertical, the other was horizontal.

After these setbacks, Aristide designed a new engine, the SPA-Faccioli N.2. The N.2 had many features in common with the N.1: water-cooling, opposed-pistons, dual crankshafts, a bevel-gear cross shaft, and counter-rotating propellers. However, the N.2 was a single cylinder engine. The engine’s magneto was driven from the cross shaft. The N.2’s intake was positioned on the bottom side of the engine, and exhaust was expelled from the top side. The N.2 had a 3.94 in (100 mm) bore and a 5.12 in (130 mm) stroke—a 10.24 in (260 mm) equivalent for the two pistons per cylinder. The engine displaced 249 cu in (4.08 L) and produced 20 hp (15 kW) at 1,200 rpm and 25 hp (19 kW) at 1,500 rpm. The N.2 weighed 106 lb (48 kg).

The N.2 engine was installed in the Faccioli N.3 aircraft. With a very similar layout to the N.2 aircraft, the N.3 pusher biplane was smaller and did not have the front-mounted elevator. Mario was again the test pilot, and he first flew the aircraft on 12 February 1910. Many flights were made throughout February and March. On 26 March 1910, one propeller came off the engine and damaged the aircraft while it was in flight. Mario was injured in the subsequent crash, and the N.3 aircraft was damaged. Aircraft and pilot flew again in the summer, but Aristide was already working on a new aircraft design.

SPA-Faccioli N3 rear

This rear view of the SPA-Faccioli N.3 shows many features common with the N.2 engine. However, note the 20 degree cylinder angle extending from the crankshafts. The camshaft was driven from the cross shaft and extended through the engine. Two pushrods extend from both the top and bottom of the camshaft. The black plugs in the center of the cylinders cover ports for spark plugs. (W. R. Pearce image)

The N.2 engine was installed in the Faccioli N.4 aircraft, a further refinement of the Faccioli line. The aircraft was first flown by Mario in July 1910. On 15 October 1910, Mario used the N.4 aircraft to get his Italian pilot’s license (No. 21). This was the first time an Italian-designed and built aircraft was used to obtain a pilot’s license.

For his next aircraft, the Faccioli N.5, Aristide needed more power. The new SPA-Faccioli N.3 engine was built upon knowledge gained from the previous engines. Again, the engine was water-cooled with opposed-pistons and had dual crankshafts (synched by a bevel-gear cross shaft) that drove counter-rotating propellers. However, the cylinder arrangement of the N.3 was unique. In essence, the N.3 was made up of two V-4 engines mounted horizontally and attached together via their combustion chambers. The cylinders of the complete engine formed a diamond shape, with the cylinders angled at 20 degrees relative to the crankshaft. This gave the cylinders a 160 degree bend at their middle. Technically, the pistons no longer shared a common cylinder, but the cylinders did still share a combustion chamber. Some sources define the N.3 as a four-cylinder opposed-piston engine, and other sources define it as an eight-cylinder engine in which opposed pairs of cylinders shared a common combustion chamber.

SPA-Faccioli N3 front

The N.3 engine’s intake manifold can be seen on the left side of the image; the exhaust ports are also visible to the right of the valves. Note the camshaft extending through the engine, and the pushrods that actuated the valves. The front side of the engine still has its two spark plugs.

Two magnetos were driven from the cross shaft at the rear of the N.3 engine. The magnetos fired one spark plug per cylinder pair. The spark plugs were positioned either on the front of the engine or on the back, depending on the cylinder. The cross shaft also drove a short camshaft that extended through the diamond between the cylinders. Via pushrods and rocker arms, the camshaft actuated the one intake and one exhaust valve for each cylinder pair. An intake manifold mounted to the front of the engine brought air and fuel into the right side of the engine, and the exhaust was expelled from the left side of the engine. The N.3 had a 2.95 in (75 mm) bore and a 5.91 in (150 mm) stroke. The engine displaced 324 cu in (5.30 L) and produced 40 hp (30 kW) at 1,200 rpm and 50 hp (37 kW) at 1,600 rpm. The N.3 weighed 198 lb (90 kg).

The N.3 engine was finished in early 1911, but the Faccioli N.5 aircraft was not. The N.3 engine was installed in the N.4 aircraft, and Mario continued his role as chief pilot. The N.3-powered N.4 aircraft was entered in various competitions during the Settimana Aerea Torinese (Turinese Air Week) held in June 1911. On 25 June 1911, the last day of the competition, a mechanical failure on the aircraft caused Mario and the N.4 to crash. As with previous crashes, Mario was injured, and the aircraft was destroyed.

Faccioli N4 aircraft

The Faccioli N.4 aircraft was originally powered by the SPA-Faccioli N.2 engine. In 1911, the eight-cylinder SPA-Faccioli N.3 engine was installed. This image was taken in June 1911, with the N.3 engine installed and Mario in the aircraft.

It is not clear if the Faccioli N.5 aircraft was ever completed. Aristide’s involvement in aviation seemed to wane after the crash of the N.4 aircraft. In fact, the last SPA-Faccioli engine may have been a development of the N.3 undertaken exclusively by SPA without much involvement from Faccioli.

Built in late 1911 or early 1912, the SPA-Faccioli N.4 engine was an enlarged and refined N.3. With the N.4, eight cylinders were again positioned in a diamond configuration, angled at 20 degrees at the crankshafts and 160 degrees at the combustion chambers. Each opposed cylinder pair shared a common combustion chamber. Each cylinder pair now had two spark plugs, and they were fired by two magnetos, one driven directly from the rear of each crankshaft. The cross shaft synchronizing the crankshafts also served as the camshaft. At the rear of the engine, the cross shaft drove pushrods that acted on rocker arms mounted to the top and bottom of the engine. The rocker arms actuated the one intake and one exhaust valve per cylinder pair, positioned at the center of the cylinders. The intake manifold was positioned behind the engine, to the left of center. The manifold fed the air/fuel mixture to a passageway in the cylinder casting that ran on the left side of the valves. The exhaust was expelled to the right of the valves.

SPA-Faccioli N4 front

The SPA-Faccioli N.4 was the final refinement of the Faccioli engine line. The magnetos can be seen behind the engine; each was driven from the rear of a crankshaft. Note the two spark plugs per cylinder pair. (W. R. Pearce image)

The N.4 engine had a 3.74 in (95 mm) bore and a 5.91 (150 mm) stroke. The engine displaced 519 cu in (8.51 L) and produced 80 hp (60 kW) at 1,200 rpm and 90 hp (67 kW) at 1,600 rpm. The N.4 was 54 in (1.38 m) wide, 32 in (.82 m) long, 22 in (.57 m) tall, and weighed 441 lb (200 kg). No information has been found to indicate that the engine was installed in any aircraft.

After surviving so many close calls, Mario Faccioli was sadly killed in a plane crash in March 1915. The type of aircraft involved in the crash is not known. Aristide Faccioli never achieved the success he strived for and never recovered from his son’s death. He took his own life on 28 January 1920.

SPA-Faccioli N.3 and N.4 engines are preserved and on display in the Museo Storico dell’Aeronautica Militare in Vigna di Valle, Italy. An N.4 engine is displayed in the Museum of Applied Arts & Sciences, Museums Discovery Centre in Castle Hill, Australia. The museum lists the engine as a “300 hp, model 2-A,” undoubtedly confusing the eight-cylinder SPA-Faccioli engine with a SPA Type 2-A straight-eight engine. Also, the N.4 is positioned upside-down in its display stand.

SPA-Faccioli N4 rear

This rear view of the N.4 engine shows how the cross shaft also acted as the camshaft and directly drove the pushrods. The valves in the foreground are for the intake. The port for the intake manifold can just be seen at the center of the engine. Note the mounts for the magnetos and that the engine is upside-down in its display stand. (Museum of Applied Arts & Sciences image)

Sources:
Origin of Aviation in Italy by Piero Vergnano (1964)
Aeronuatica Militare Museo Storico Catalogo Motori by Oscar Marchi (1980)
Jane’s All the World’s Aircraft 1912 by Fred T. Jane (1912/1968)
http://collection.maas.museum/object/206770
http://www.treccani.it/enciclopedia/aristide-faccioli_(Dizionario-Biografico)/
http://it.wikipedia.org/wiki/Aristide_Faccioli

Martin-Baker MB5 dH front

Martin-Baker MB5 Fighter

By William Pearce

On 12 September 1942, the Martin-Baker MB3 fighter crashed after its Napier Sabre engine seized. Company co-founder Captain Valentine H. Baker was killed during the attempted forced landing. James Martin, the aircraft’s designer, had already designed the MB3A, which was the production version of the MB3 that incorporated several changes to enhance the fighter’s performance. The second MB3 prototype was to be completed as a MB3A. After the MB3 was destroyed and Baker was killed, Martin wanted to further alter the aircraft’s design to improve its safety and performance. Perhaps the paramount change was to replace the Sabre engine with a Rolls-Royce Griffon.

Martin-Baker MB5 Rotol front

The Martin-Baker MB5 was one a few aircraft that sat at the pinnacle of piston-engine fighter development. Here, the aircraft is pictured at Harwell around the time of its first flight. The Rotol propeller is installed but the 20 mm cannons are not.

The British Air Ministry doubted the quick delivery of the two MB3 prototypes still on order and was agreeable to a contract change. They authorized the construction of a single prototype of the new aircraft design designated MB5. The MB5 was given serial number R2496, which was originally allocated to the second and never-built MB3 aircraft. The third MB3 prototype was cancelled.

The Martin-Baker MB5 was officially designed to the same Air Ministry Specification (F.18/39) as the MB3. Also, the aircraft’s construction closely followed the methods used on the MB3. The aircraft’s fuselage was made of a tubular steel frame with bolted joints. Attached to the frame were formers that gave the fuselage its shape. Aluminum skin panels were attached to the formers, and detachable panels were used wherever possible. A rubber seal attached to the formers ensured the tight fit of the detachable skin panels, which were secured by Dzus fasteners. The large and easily removed panels helped simplify the aircraft’s service and maintenance.

Martin-Baker MB5 Rotol org tail rear

Again, the MB5 is shown at Harwell. The original vertical stabilizer and rudder were very similar to those used on the MB3. The inner gear doors are not installed on the aircraft.

The MB5’s wings were very similar to those used on the MB3, except that each housed only two 20 mm cannons with 200 rpg. All control surfaces used spring servo tabs; the rudder was fabric-covered, but all other control surfaces were metal-covered. The aircraft’s brakes, split flaps, and fully retractable landing gear were pneumatically controlled, and the air system operated at 350 psi (24.13 bar). The main wheels had a wide track of 15 ft 2 in (4.62 m). Two fuel tanks were housed in the aircraft’s fuselage: an 84 gallon (318 L) tank was positioned in front of the cockpit, and a 156 gallon (591 L) tank was positioned behind the cockpit. The cockpit was positioned directly above the wings and was enclosed with a bubble canopy. The cockpit had very good visibility, and its design was praised for the excellent layout of gauges and controls. The three main gauge clusters hinged downward for access and maintenance.

The MB5 was powered by a Rolls-Royce Griffon 83 engine capable of 2,340 hp (1,745 kW) with 25 psi (1.72 bar) of boost and 130 PN fuel. The engine originally turned a six-blade Rotol contra-rotating propeller, but by late 1945, a 12 ft 6 in (3.81 m) de Havilland contra-rotating unit was installed. A small scoop under the spinner brought in air to the Griffon’s two-speed, two-stage supercharger. The intercooler, radiator, and oil cooler were arranged, in that order, in a scoop under the fuselage. This arrangement provided some heat to the oil cooler when the engine was first started and prevented the oil from congealing and restricting the flow through the cooler.

Martin-Baker MB5 2nd tail

An intermediate modification to the MB5’s tail involved a more vertical leading edge that increased the fin’s area. This version of the tail did not last long before the completely redesigned unit was installed. The aircraft still has the Rotol propeller.

The aircraft had a 35 ft (10.7 m) wingspan, was 37 ft 9 in (11.5 m) long, and was 14 ft 4 in (4.4 m) tall. The MB5 had a maximum speed of 395 mph (636 km/h) at sea level, 425 mph (684 km/h) at 6,000 ft (1,829 m), and 460 mph (740 km/h) at 20,000 ft (6,096 m). Normal cruising speed was 360 mph (578 km/h) at 20,000 ft (6,096 m). The aircraft stalled at 95 mph (153 km/h) clean and at 78 mph (126 km/h) with flaps and gear extended. The MB5 had an initial rate of climb of 3,800 fpm (19.3 m/s) and could reach 20,000 ft (6,096 m) in 6.5 minutes and 34,000 ft (10,363 m) in 15 minutes. The MB5’s service ceiling was 40,000 ft (12,192 m), and it had a range of around 1,100 miles (1,770 km). The aircraft had an empty weight of 9,233 lb (4,188 kg), a normal weight of 11,500 lb (5,216 kg), and an overload weight of 12,090 lb (5,484 kg).

Construction of the MB5 started in 1943, and some components (possibly the wings and tail) of the second MB3 prototype were used in the MB5. The work on the aircraft was delayed because of other war work with which Martin-Baker was involved. In addition, Martin continued to refine and tinker with the MB5’s design, much to the frustration of the Air Ministry. However, the Air Ministry decided that Martin was going to do whatever he thought was right and that the best course of action was to leave him alone; the MB5 would be done when Martin decided it was done.

Martin-Baker MB5 dH front

The MB5 pictured close to its final form. The de Havilland propeller, inner gear doors, and taller vertical stabilizer and rudder have been installed. Note the smooth lines of the cowling. The position of the cockpit gave a good view over the aircraft’s nose and wings.

Captain Baker was Martin-Baker’s only test pilot and was never replaced. As the MB5 neared completion in the spring of 1944, Rotol test pilot (Leslie) Bryan Greensted was loaned to fly the aircraft. On 23 May 1944, the MB5 was disassembled and trucked from Martin-Baker’s works in Denham to the Royal Air Force (RAF) station in Harwell. The aircraft was reassembled and underwent some ground runs. Later that same day, Greensted took the MB5 aloft for its first test flight. To disassemble, transport, reassemble, and flight test an aircraft all in one day speaks to the MB5’s impressive design.

Greensted was not overly impressed with the aircraft’s first flight, because the MB5 exhibited directional instability; in fact, he said the aircraft “was an absolute swine to fly.” Martin listened intently to Greensted’s comments and immediately went to work on a solution. The increased blade area of the contra-rotating propellers had a destabilizing effect when coupled with the MB3 tail that was originally used on the MB5. To resolve the issue, Martin designed a taller vertical stabilizer and rudder, which were fitted to the MB5. The change took six months for Martin to implement, but when Greensted flew the aircraft, he was impressed by its performance and handling. In addition, a new horizontal stabilizer was fitted, but it is not known exactly when this was done. From its first flight until October 1945, the MB5 accumulated only about 40 flight hours. Martin-Baker had been informed around October 1944 that no MB5 production orders would be forthcoming, given that the war was winding down, and any production aircraft would most likely enter service after the war was over.

Martin-Baker MB5 dHf

The MB5 undergoing maintenance. A large panel has been removed from under the aircraft, and one of the inner gear doors has also been removed. Note the Dzus fasteners on the cowling and that the spinner is now painted black. The small scoop under the spinner delivered air to the engine’s supercharger.

Some sources state the MB5 was prepared for a speed run in the fall of 1945. The Griffon engine was boosted to produce 2,480 hp (1,849 kW), and the aircraft reached 484 mph (779 km/h) on a measured course near Gloucester. However, the speed record claim seems highly doubtful. On 29 October 1945, the MB5 was one of the aircraft exhibited at the Royal Aircraft Establishment (RAE) Farnborough. It was the only aircraft present that had contra-rotating propellers. While Greensted was demonstrating the aircraft before Winston Churchill and RAF officials, the Griffon engine failed. With his vision obscured by oil and some smoke in the cockpit, Greensted jettisoned the canopy. The canopy flew back and struck the tail, but Greensted was able to land the MB5 without further damage.

The MB5 had accumulated around 80 flight hours by the time it was handed over to the Aeroplane and Armament Experimental Establishment (A&AEE) at Boscombe Down. In March, April, and May 1946, the MB5 was flown by various pilots, and the aircraft’s performance and handling characteristics were well praised, but it was noted that the MB5’s acceleration and its roll rate were not quite on par with contemporary fighters. Overall, the tests showed that the MB5 was an excellent aircraft and that it was greatly superior from an engineering and maintenance standpoint to any other similar type. The MB5 was back at RAE Farnborough for an exhibition in June 1946. During the show, Polish Squadron Leader Jan Zurakowski flew the aircraft in a most impressive display and later stated that the MB5 was the best airplane he had ever flown.

Martin-Baker MB5 show

The MB5 was present at RAE Farnborough in October 1945. The display featured the latest British aircraft and several captured German aircraft. In the foreground is a Supermarine Spiteful and the MB5, with its 20 mm cannons installed. Other visible British aircraft include a Blackburn Firebrand, Bristol Brigand, Fairey Firefly, and Fairey Spearfish. Visible German aircraft include a Dornier Do 335, Fieseler Fi 103, Junker Ju 188, a pair of Focke-Wulf Fw 190s, and a Messerschmitt Bf 109. Many other British and German aircraft were present at the display.

The MB5 was flown sparingly until a number of flights were made toward the end of 1947. Wing Commander Maurice A. Smith flew the aircraft during this time and highly regarded the MB5’s layout and performance. From mid-November to the end of 1947, the MB5 was loaned to de Havilland at Hatfield for propeller testing. In 1948, the aircraft returned to RAE Farnborough, where it was flown by legendary pilot Captain Eric ‘Winkle’ Brown. Although Brown was slightly critical of the aircraft’s lateral handling qualities, he said the MB5 was an outstanding aircraft and that he had never felt more comfortable in a new aircraft.

On 5 May 1948, the MB5 was sent to the Air Ministry Servicing Development Unit at RAF Wattisham. There, it served as a training airframe until it was moved to RAF Bircham Newton around 1950. Reportedly, the MB5 was used as a ground target until its battered remains were burned in 1963—an inglorious end for such a fine aircraft.

Martin-Baker MB5 takeoff

The MB5 taking off from Chalgrove in 1948 with Wing Commander Maurice A. Smith at the controls. The MB5’s flaps did not have any intermediate positions—they were either up or down. The 20 mm cannons have been removed. Note the belly scoop’s outward similarity to the scoop used on the P-51 Mustang.

The Martin-Baker MB5 is one of a handful of aircraft that demonstrated superlative performance and flight qualities yet never entered production due to the end of World War II and the emergence of jet aircraft. It is quite impressive that the MB5 was created by a small firm that produced a total of four outstanding aircraft—each being a completely different model. Despite the quality of Martin-Baker’s aircraft and their best efforts to enter the aircraft manufacturing business, the MB5 was the company’s last aircraft. Martin-Baker turned their attention to other aircraft systems and became a pioneer and world leader in ejection seat technology.

An MB5 replica has been under construction by John Marlin of Reno, Nevada for a number of years. Although not an exact copy, Marlin’s reproduction is a labor of love intended to commemorate one of the most impressive aircraft of all time and to honor all who created the original MB5.

Martin-Baker MB5 Martin

James Martin is pictured in front of his masterpiece, the MB5. Martin-Baker’s aircraft never found success; however, the company’s ejection seats have saved thousands of lives and are still in production.

Sources:
RAF Fighters Part 2 by William Green and Gordon Swanborough (1979)
British Experimental Combat Aircraft of World War II by Tony Buttler (2012)
Wings of the Weird & Wonderful by Captain Eric ‘Winkle’ Brown (1983/2012)
Sir James Martin by Sarah Sharman (1996)
“The Martin-Baker M-B V” Flight (29 November 1945)
“M-B V in the Air” by Wing Commander Maurice A. Smith, Flight (18 December 1947)
“Martin-Baker Fighters,” by Bill Gunston, Wings of Fame Volume 9 (1997)
The British Fighter since 1912 by Francis K. Mason (1992)
http://johnmarlinsmb5replica.mysite.com/index_1.html

Isotta Fraschini Zeta rear

Isotta Fraschini Zeta X-24 Aircraft Engine

By William Pearce

In 1900, Cesare Isotta and Vincenzo Fraschini formed Isotta Fraschini (IF) in Milan, Italy. The firm originally imported automobiles, but began manufacturing its own vehicles by 1904. In 1908, IF started experimenting with aircraft engines and began producing them by 1911. The company went on to build successful lines of air-cooled and water-cooled engines. In the early 1930s, IF experienced financial issues caused in part by the great depression. In 1932, the Italian aircraft manufacturer Caproni purchased IF and continued production of automobiles and engines (both aircraft and marine).

Isotta Fraschini Zeta front

The Isotta Fraschini Zeta used many components from the Gamma V-12 engine. The air-cooled, X-24 Zeta had its cylinder banks at 90 degrees, and cooling the rear cylinders proved to be a problem. (Kevin Kemmerer image)

In the late 1930s, IF developed a pair of inverted, 60 degree, V-12, air-cooled engines. The first of the engines was the Gamma. The Gamma had a 4.92 in (125 mm) bore and a 5.12 in (130 mm) stroke. The engine displaced 1,168 cu in (19.1 L) and produced 542 hp (404 kW) at 2,600 rpm. The second engine was the Delta; it had the same architecture as the Gamma but had a larger bore and stroke of 5.20 in (132 mm) and 6.30 in (160 mm) respectively. The Delta displaced 1,603 cu in (26.3 L) and produced 790 hp (589 kW) at 2,500 rpm.

In 1939, the Ministero dell’Aeronautica (Italian Air Ministry) worked to import Daimler-Benz aircraft engines from Germany and obtain licenses for their production. IF decided to design an engine powerful enough to compete with the Daimler-Benz engines or replace them if sufficient quantities could not be imported.

To speed engine development, IF created the new engine using as much existing technology as possible. Essentially, two Gamma engines were mounted on a common crankcase in an X configuration to create the new engine, which was called the Zeta. The use of air-cooling and a single crankshaft simplified the design of the 24-cylinder Zeta engine.

Isotta Fraschini Zeta rear

All of the Zeta’s accessories were driven at the rear of the engine. A camshaft housing spanned all of the cylinders for one cylinder bank. Note the two spark plug leads for each cylinder extending from the top of the camshaft housing. The pipes for the air starter can been seen on the upper cylinder bank. (Kevin Kemmerer image)

The Isotta Fraschini Zeta was made up of an aluminum crankcase with four cylinder banks, each with six individual cylinders. All cylinder banks were positioned 90 degrees from one another. Each air-cooled cylinder was secured to the crankcase by ten bolts, and the cylinder’s steel liner extended into the crankcase. Each cylinder had two spark plugs that were fired by magnetos positioned at the rear of the cylinder bank.

Each cylinder had one intake and one exhaust valve. Mounted to the top of each bank of cylinders was a camshaft housing that contained dual overhead camshafts. A vertical shaft at the rear of the cylinder bank directly drove the exhaust camshaft. A short cross shaft drove the intake camshaft from the exhaust camshaft. The crankshaft was supported by seven plain bearings, and each connecting rod served four cylinders via a master rod and three articulating rods.

An accessory section at the rear of the engine drove the magnetos, vertical drives for the camshafts, and a single-stage supercharger. The supercharger forced air through intake manifolds between the upper and lower cylinder Vees. The exhaust gases were expelled from the cylinders via individual stacks between the left and right cylinder Vees. A pressurized air starting system was used, and the engine had a compression ratio of 6.5 to 1. The Zeta maintained the 4.92 in (125 mm) bore and 5.12 in (130 mm) stroke of the Gamma. The Zeta displaced 2,336 cu in (38.3 L) and produced 1,233 hp (919 kW) at 2,700 rpm. The engine was around 68 in (1.73 m) long, and 39 in (1.00 m) wide and tall. The Zeta weighed approximately 1,675 lb (760 kg).

Caproni F6Z IF Zeta

The Caproni Vizzola F.6MZ was the only aircraft to fly with a Zeta engine. The close-fitting cowl can be seen bulging around the engine’s cylinder banks, and the removed panels show just how tight of a fit the cowling was. Note the gap around the propeller for cooling air.

The Zeta RC45 was first run on 28 February 1941, and development was slowed due to various design issues. The engine was also having trouble making the forecasted output, with only around 1,085 hp (809 kW) being achieved. As development progressed, many of the issues were resolved, but the engine still lacked power. In May 1943, the Zeta RC24/60 with a two-speed supercharger was run, but the engine was not able to pass its type test. A number of aircraft were considered for conversion from their initial engines to the Zeta, but serious progress was made on only two aircraft.

The Caproni Vizzola F.6M was an all-metal aircraft based on the Caproni Vizzola F.5 but powered by a 1,475 hp (1,100 kW), liquid-cooled, Daimler-Benz DB 605 engine. While the F.6M was being developed, the design of a second version of the aircraft powered by a Zeta RC45 engine was initiated on 7 October 1941. The new design was called F.6MZ (or just F.6Z). The Zeta-powered aircraft was ordered on 16 June 1942, and it was assigned serial number (Matricola Militare) MM.498. The engine change came about because reliable deliveries of the DB 605 and its license-built contemporary, the FIAT RA 1050, could not be assured.

Progress on the Caproni Vizzola F.6MZ was delayed because of the engine. While the F.6M first flew in September 1941, it was not until 14 August 1943 that the F.6MZ took flight. The F.6MZ had a tight-fitting cowling that bulged around the engine’s four valve covers, and four rows of short exhaust stacks protruded from the cowling. Cooling air was taken in from around the spinner, and the air was expelled via an annular slot at the rear of the cowling. An oil cooler was housed in a chin radiator below the cowling.

Caproni Vizzola F6Z

The F.6MZ was first flown on 14 August 1943. The two rows of exhaust stacks can be seen near the cylinder bank bulges. The cooling air exit flaps can just be seen at the rear of the cowling.

First flown by Antonio Moda, the F.6MZ had an estimated top speed of 391 mph (630 km/h), some 37 mph (60 km/h) faster than the F.6M. This speed seems optimistic, considering the Zeta had an output of at least 225 hp (168 kW) less than the DB 605 and that the F.6MZ could not have produced significantly less drag or have been much lighter than the F.6M. The Zeta engine experienced overheating issues throughout the flight test program—the rear cylinders did not have sufficient airflow for proper cooling. Some modifications were made, but further flight tests were halted with Italy’s surrender on 8 September 1943. Two F.6MZ aircraft were ordered, but only the first prototype was built.

In October 1941, Regia Aeronautica (Italian Royal Air Force) requested that Reggiane (Officine Meccaniche Reggiane) replace the DB 605 / FIAT RA 1050 in its RE 2005 Sagittario fighter with the IF Zeta RC24/60. Reggiane was another company owned by Caproni. The Zeta-powered aircraft, developed after the RE 2005, was the Reggiane RE 2004, and seven examples were ordered. Although Reggiane was less enthusiastic about the Zeta than Caproni Vizzola, they did work on designing a firewall-forward engine package.

Isotta Fraschini Zeta SM79

These four images show the Zeta RC24/60 engine installed in the nose of a SM.79. Once tested, this installation would be applied to the Reggiane RE 2004. Note how the exhaust stack arrangement was completely different from that used on the F.6MZ.

A Zeta engine was not delivered to Reggiane until 1943. At the time, Reggiane was building Savoia-Marchetti SM.79 Sparviero three-engined bombers. One SM.79 was modified to have the Zeta engine installed in the nose position. This would enable the engine to be flight tested, and the cooling characteristics of the cowling configuration could be evaluated before the engine was used in the RE 2004. Compared to the F.6Z cowling, the Reggiane cowling had a larger diameter but was a cleaner design. Again, cooling air was brought in from around the spinner and exited through an annular slot at the rear of the cowling, and an oil cooler was positioned below the cowling. The Reggiane installation used exhaust stacks that ended with two close rows along the sides of the cowling. It appears that the Italian surrender occurred before the Zeta engine was ever flown in the SM.79. In fact, the Zeta RC24/60 was never cleared for flight, and the engine used in the SM.79 was most likely a mockup without all of its internal components. Although never built, the RE 2004 had an estimated top speed of 385 mph (620 km/h), 36 mph (58 km/h) slower than the RE 2005. At 7,117 lb (3,228 kg), the RE 2004 was 842 lb (382 kg) lighter than the RE 2005.

IF also designed the Sigma, a larger X-24 engine using cylinders and other components from the inverted, V-12, air-cooled Delta. The Sigma had a 5.20 in (132 mm) bore and 6.30 in (160 mm) stroke. The engine displaced 3,207 cu in (52.5 L) and had an estimated output of 1,578 hp (1,178 kW) at 2,400 rpm. The Sigma was never built, but its approximate dimensions were 82 in (2.08 m) long, and 45 in (1.15 m) wide and tall. The engine weighed around 2,160 lb (980 kg).

Isotta Fraschini Zeta SM79 cowling

The Zeta installation for the RE 2004 (as seen on the SM.79) was fairly clean but somewhat spoiled by the large oil cooler under the cowling. Note the cooling air exit gap at the rear of the cowling.

Sources:
https://it.wikipedia.org/wiki/Isotta_Fraschini_Zeta
Tutti gli aerie del Re by Max Vinerba (2011)
Italian Civil and Military Aircraft 1930-1945 by Jonathan W. Thompson (1963)
I Reggiane dall’ A alla Z by Sergio Govi (1985)
The Caproni-Reggiane Fighters 1938-1945 by Piero Prato (1969)
Ali E Motori D’Italia by Emilio Bestetti (1939)
Isotta Fraschini: The Noble Pride of Italy by Tim Nichols (1971)

Schwerer Gustav firing test

Krupp 80 cm Kanone Schwerer Gustav (Dora) Railway Gun

By William Pearce

In the 1930s, France constructed the Maginot Line, which was a series of fortifications and obstacles intended to protect the country against invasion from the east (Germany). The Maginot Line was to serve as an impenetrable wall of defense. Naturally, when one country develops a new defensive technology, other countries rush to develop a way to defeat that technology.

Schwerer Gustav firing test

The Krupp 80 cm Kanone (E) Schwerer Gustav / Dora being readied for a test firing on 19 March 1943 at Rügenwalde, Germany. Albert Speer (right), Adolf Hitler (second from right), and a number of other officials observed the firing. Hitler referred to the impractical gun as “meine stählerne faust (my steel fist).”

After studying details of Maginot Line fortifications that were published in French newspapers, it became apparent to German Wehrmacht (combined armed forces) planners that they did not possess any weapon capable of penetrating the fortifications. In 1935, the Wehrmacht requested Friedrich Krupp AG (Krupp), a heavy industry conglomerate in Essen, Germany, to prepare ballistics reports for guns firing 27.6, 31.5, 33.5, and 39.4 in (70, 80, 85, and 100 cm) shells. The goal was to fire the gun outside of the enemy’s artillery range and be able to penetrate 23 ft (7 m) of reinforced concrete or 3 ft (1 m) of steel armor. The Krupp factory dutifully ran the calculations and supplied the requested information but took no further action.

In March 1936, Adolf Hitler visited the Krupp factory and asked Gustav Krupp (von Bohlen und Halbach), head of the Krupp organization, what type of weapon was needed to smash through the Maginot Line. Krupp, recalling the recent report, was able to answer Hitler’s question in some detail. Krupp explained that a 33.5 in (80 cm) railway gun could be constructed and would be able to defeat the Maginot Line. After Hitler’s visit, Krupp directed his design staff to begin the layout of such a weapon. Erich Müller was the head of the artillery development department at Krupp and began working on the gun’s design.

Schwerer Gustav cradle assymbly

Nicknamed Dora by its crew, the massive gun was broken down into 25 pieces and transported by rail to its firing location. Two gantry cranes were used to reassemble the gun. Here, the cradle is being positioned into the carrier. Note the three normal railroad tracks and the special track for the cranes.

In early 1937, Krupp met with Hitler and presented him with the design for the 33.5 in (80 cm) railway gun. Hitler approved of what he saw, and the German Army High Command (Oberkommando des Heeres) commissioned Krupp to build three guns under the designation 80 cm Kanone (E). However, the guns quickly became known as Schwerer Gustav (Heavy Gustav), named after Gustav Krupp. Hitler wanted the first gun to be ready by March 1940.

The Schwerer Gustav was an absolutely huge weapon. The rifled barrel consisted of two halves, with the rear half covered by a jacket. The complete barrel was 106 ft 7 in (32.48 m) long, and its rifling was .39 in (10 mm) deep. Attached to the rear of the barrel was the cradle and breechblock. Mounted to the cradle were four hydraulic recoil absorbers. Trunnions held the gun’s cradle in two huge carriers and enabled the barrel to be elevated from 0 to 65 degrees. Each carrier was supported by four railroad trucks: two in the front and two in the rear. Each of the eight trucks was made up of five axles, giving the Schwerer Gustav a total of 80 wheels that were carried on two parallel sets of railroad tracks. The gun used a diesel-powered generator to provide power to run its systems. The Schwerer Gustav was 155 ft 2 in (47.30 m) long, 23 ft 4 in (7.10 m) wide, and 38 ft 1 in (11.60 m) tall. The barrel, cradle, and breech weighed 881,848 lb (400,000 kg), and the complete gun weighed 2,976,237 lb (1,350,000 kg).

Schwerer Gustav assymbly tracks

This image gives a good view of the tracks needed to assemble the Schwerer Gustav. One pair of D 311 locomotives is positioned in front of the gun.

In addition to needing parallel tracks, the Schwerer Gustav required its track to be curved up to 15 degrees. The gun had no built-in ability to traverse, so horizontal aiming (azimuth) was accomplished by moving the entire gun along the curved track. Extra bracing was added to the inside rail of both tracks along the shooting curve. This bracing helped prevent the tracks from being damaged due to the gun’s recoil. A massive effort was needed to transport and set up the Schwerer Gustav for firing.

The gun was broken down and transported on 25 freight cars, which did not include crew or supplies. Near where the gun was to be deployed, a spur line was laid from the main rail line. Three parallel tracks were then laid where the Schwerer Gustav was to be assembled. Two of the tracks supported the gun, and the third track allowed for parts and equipment to be brought in. A single rail was laid on both sides of the three parallel tracks. These widespread rails were for two gantry cranes to take parts from the third track and move them in position to assemble the Schwerer Gustav. Two parallel tracks extended from the assembly point to the firing position of the Schwerer Gustav. Dirt was piled up high on both sides of the double track to protect the gun from attack and allow it to be covered by camouflage netting. It took around 250 men 54 hours to assemble the Schwerer Gustav, and it took weeks for 2,000 to 4,500 men to lay the needed tracks and prepare the gun’s firing position. In addition, two Flak (Flugabwehrkanone or air defense cannon) battalions were needed to protect the gun from an aerial assault.

Schwerer Gustav captured shell

Allied soldiers pose in front of a captured projectile (left) and an obturation case (right). The projectile had a ballistic nose cone made of aluminum.

Krupp built special diesel-electric locomotives to move the Schwerer Gustav into firing position and to transport supplies. These locomotives were designated D 311, and two were paired together to act as a single unit, for a total of four engines to move the gun. Each locomotive was powered by a 940 hp (700 kW) six-cylinder MAN diesel engine. The engine ran a generator that provided power to traction motors mounted on the locomotive’s bogies. Ammunition was delivered via the twin rails behind the Schwerer Gustav. Hoists on the back of the gun would lift the ammunition to the firing deck. The shell was hoisted up one side of the gun, and the powder bags and a brass obturation case were hoisted up the other side. A hydraulic ram loaded the shell into the breach, followed by the powder bags and the case. Once loaded, the gun was raised into firing position. It took 20 to 45 minutes to load the gun and prepare it for firing. Only 14 to 16 shots could be fired each day.

Two types of shells were fired from the Schwerer Gustav: armor piercing (AP) and high explosive (HE). The AP rounds were 11 ft 10 in (3.6 m) long and were fired with 4,630 lb (2,100 kg) of propellant. The AP round was made of chrome-nickel steel. It weighed 15,653 lb (7,100 kg) and carried 551 lb (250 kg) of explosives. The AP shell had a muzzle velocity of 2,362 fps (720 m/s) and a maximum range of 23.6 miles (38 km). At maximum range, the AP projectile reached an altitude of around 39,370 ft (12 km) and was in the air for two minutes. The HE ammunition was around 13 ft 9 in (4.2 m) long and was fired with 4,938 lb (2,240 kg) of propellant. The HE rounds weighed 10,582 lb (4,800 kg) and carried 1,543 lb (700 kg) of explosives. The HE shell had a muzzle velocity of 2,690 fps (820 m/s) and a maximum range of 29.2 miles (47 km). Upon impact, the HE projectile created a crater some 33 ft (10 m) wide and deep. The muzzle velocity for both the AP and HE shells was over twice the speed of sound, and both were fitted with an aluminum alloy ballistic nose cone. Spotter aircraft were used to direct the gun’s fire and assess the results.

Construction of the Schwerer Gustav started in the spring of 1937, but forging the huge and complex barrel resulted in serious delays. By 1939, Alfried Krupp (von Bohlen und Halbach) began to take over company leadership from his father, whose health had begun to fail. In late 1939, testing started on sample components, and the gun’s AP projectile was able to successfully penetrate 23 ft (7 m) of concrete or 3 ft (1 m) of steel. It was obvious that the Schwerer Gustav would not be ready by the March 1940 deadline Hitler had requested.

Schwerer Gustav hoists

Shells and propellant for the gun were delivered by rail and hoisted up to the firing deck. The shell is on the far side, and the case with powder bags is in front of it (to the right). It took 20 to 45 minutes to reload the gun and prepare it for firing.

In May 1940, Germany invaded Belgium and France. Since the Maginot Line ended at Belgium, rather than extending to the English Channel, Germany was able to simply go around the static fortifications and enter France. On 25 June 1940, France surrendered to Germany.

With the fall of France, the Schwerer Gustav was no longer needed, but discussions ensued regarding other fortifications that the gun could be used against. Many in the Wehrmacht felt the gun was impractical and not worth the resources its construction consumed, let alone the manpower needed to deploy the gun. However, the Schwerer Gustav had become one of Hitler’s personal projects, so its development continued. Alfried Krupp hosted Hitler for a test firing during the gun’s acceptance trials in early 1941 at Rügenwalde, Germany (now Darłowo, Poland). Further tests and development continued through 1941. Some sources indicate that 250 rounds were fired from the gun during its testing.

Schwerer Gustav firing position

The gun was positioned on a shooting curve to allow for horizontal aiming. Rectangular braces were positioned on both sides of the inner rails to protect the tracks from the forces of firing the gun.

On 8 January 1942, Schwere Artillerie-Abteilung (E) 672 (Heavy Artillery Division E 672) was established with 1,420 men and with Oberst (Colonel) Robert Böhm as its commander. The unit was formed to deploy the Schwerer Gustav. As the artillerymen worked on the gun, they called it “Dora,” and the nickname stuck. From that time on, the gun was typically referred to as Dora, rather than Schwerer Gustav. The different names led to some confusion regarding how many guns were built and when they were used. German sources typically indicate that Dora was a nickname from the artillerymen and that only one gun was ever deployed. However, many English sources state that Gustav and Dora were the first and second guns built and that the Dora gun was named in honor of Erich Müller’s wife.

In February 1942, the division was sent to Bakhchisaray in the Crimean Peninsula, then part of the Soviet Union. The gun was to be used on the port city of Sevastopol, 18.6 miles (30 km) southwest of Bakhchisaray. Sevastopol had been under siege by German forces since November 1941. Five separate trains were used to transport the gun, the division, ammunition, supplies, and workshops to the deployment site. The Schwerer Gustav arrived in early March. In May, German troops and civilian workers laid a 1.2 mile (2 km) long access track to the firing site, followed by parallel tracks .75 miles (1.2 km) long for gun assembly and deployment. Once the track was ready, assembly of the gun commenced.

On 5 June 1942, the Schwerer Gustav fired its first round at Sevastopol, and 13 additional shots followed that day. On 6 June, the Schwerer Gustav achieved the highpoint of its career. An ammunition magazine at White Cliff suffered a direct hit from the Schwerer Gustav. The magazine was buried 98 ft (30 m) under Severnaya Bay and had 33 ft (10 m) of concrete protection. The AP round passed though the water, ground, and concrete before detonating the magazine. At least one ship was also sunk after being damaged by blast waves from the impact of nearby shells.

Schwerer Gustav firing

The Schwerer Gustav could fire a 15,653 lb (7,100 kg) AP shell 23.6 miles (38 km) or a 10,582 lb (4,800 kg) HE shell 29.2 miles (47 km). A spotter aircraft directed fire and assessed the results.

The gun was used on three additional days before its ammunition was exhausted. The Schwerer Gustav fired a total of 48 shells at the city, and its barrel had become worn. Some sources claim that the barrel had a 300-round life and was the same one that had fired the 250 test rounds. Other sources state the barrel was new and should have been able to fire 100 shots before it became worn, but signs of wear were seen after as few as 15 shots. Regardless, the Schwerer Gustav’s barrel was replaced with a spare, and the original barrel was transported back to Germany for repairs. Of the 48 rounds fired, only 10 fell within 197 ft (60 m) of their target, with the most off-target shot landing 2,428 ft (740 m) from its intended point of impact. However, each huge shell caused massive damage all around its impact site.

A few weeks after Sevastopol fell on 4 July 1942, Gustav Krupp gave the first Schwerer Gustav to Hitler as a personal gift and a sign of his support and allegiance to the Third Reich. The Krupp company would only accept payment for subsequent guns. The Schwerer Gustav was moved and redeployed for a planned offensive against Leningrad, which was also under siege. The gun had been assembled and placed in firing position, but its planned use was cancelled. The Schwerer Gustav was disassembled and taken back to Rügenwalde.

The gun was overhauled, and an improved, lined barrel was fitted. A test firing on 19 March 1943 at Rügenwalde was attended by Hitler, Albert Speer, Alfried Krupp, and a number of other officials. Two shots were fired, with the second shell impacting 29.2 miles (47 km) away. The Schwerer Gustav was then disassembled and placed in storage near Chemnitz, Germany in September 1943. The gun remained there until 14 April 1945, when it was destroyed by German troops one day before US soldiers captured the area. Parts of the Schwerer Gustav were recovered by the Soviets and supposedly transported to Russia. The second Schwerer Gustav was reportedly completed but never deployed. In March 1945, it was moved from Rügenwalde to Grafenwöhr, Germany, where it was destroyed on 19 April 1945.

Schwerer Gustav shooting curve

While it was a powerful weapon, the Schwerer Gustav required a tremendous amount of resources for its construct and deployment. Its size and complexity severely limited where and when the gun could be deployed and also made it very susceptible to aerial attack.

Around November 1943, plans were initiated to use a cannon to shell Britain from across the English Channel. It was decided that the third Krupp 80 cm Kanone (E) would be built as the gun for this purpose. In order to send a shell 99 to 124 miles (160 to 200 km), a projectile 20.5 in (52 cm) in diameter and weighing 1,499 lb (680 kg) would be shot out of a barrel 157 ft (48 m) long. This gun was named Länger Gustav (Longer Gustav). The gun was damaged during a bombing raid while it was still under construction. Some components for the Länger Gustav were discovered at the Krupp factory in Essen by Allied troops in 1945.

In December 1942, Krupp proposed a self-propelled 80 cm Kanone (E) known as the Landkreuzer P. 1500 Monster. The P. 1500 used the same 31.5 in (80 cm) main gun as the Schwerer Gustav, but it also had two 5.9 in (15 cm) sFH 18.1 L/30 field guns and a number of 15 mm MG151/15 cannons. Powering the P. 1500 were four 2,170 hp (1,618 kW) nine-cylinder MAN M9V 40/46 diesel engines. The P. 1500 was 137 ft 10 in (42 m) long, 59 ft 1 in (18 m) wide, and 23 ft (7 m) tall. True to its name, the Monster weighed 3,306,930 lb (1,500,000 kg). Requiring a crew of over 100, the machine had an estimated top speed of 9.3 mph (15 km/h) and a range of 31 miles (50 km). The P. 1500 project was cancelled in 1943 by Albert Speer, the Minister for Armaments, before any serious work had been done.

After the war, Alfried Krupp and Erich Müller, the gun’s designer, were sentenced to 12 years in prison for crimes against humanity by participating in the plundering, devastation, and exploitation of occupied countries and by participating in the murder, extermination, enslavement, deportation, imprisonment, torture, and use for slave labor of German nationals, prisoners of war, and civilians who came under German control. Krupp was pardoned after three years, and Müller was released after four years.

Schwerer Gustav 1 destruction

The first Schwerer Gustav gun was destroyed by German troops on 14 April 1945 to prevent its capture by US forces. Some sources state that the gun was recovered by the Soviets. A US soldier poses in front of the gun’s cradle. The girders attached to the cradle were used for transporting and mounting the cradle to the rest of the gun. The circular pad behind the soldier is a trunnion mount.

While the Schwerer Gustav was mechanically a well-engineered weapon, its requirements for use made it very impractical and nearly useless. The Maginot Line was easily bypassed, rather than penetrated, calling into question why the Schwerer Gustav was needed in the first place. However, Hitler liked the gun and called it his “steel fist.” It was the type of grandiose weapon that Hitler felt displayed the technological superiority of the Third Reich.

No large pieces of the Schwerer Gustav guns remain. However, a number of inert projectiles and cases are preserved in various museums. After the war, the D 331 locomotives were redesignated V 188 and used to haul freight for the West German Railway (Deutsche Bundesbahn).

Schwerer Gustav 2 destruction

Germans destroyed part of the second Schwerer Gustav on 19 April 1945 to prevent its capture. A US soldier gives scale to the gun’s barrel. The second gun’s cradle, which was blown up, can be seen on the left.

Sources:
http://de.wikipedia.org/wiki/80-cm-Kanone_(E)
http://en.wikipedia.org/wiki/Schwerer_Gustav
http://ww2db.com/weapon.php?q=89
http://samilitaryhistory.org/vol124lw.html
http://html2.free.fr/canons/dora.htm
http://de.wikipedia.org/wiki/Wehrmachtslokomotive_D_311
http://www.modellbahn.com/37283.V188.html
http://www.e94114.de/V188.htm
http://www.militaryfactory.com/armor/detail.asp?armor_id=480
http://en.wikipedia.org/wiki/Landkreuzer_P._1500_Monster