Question: What type of engine does Stanley Hooker and Bristol Proteus have in common?

Context paragraphs:
1958 London Vickers Viking accident: The London Vickers Viking accident occurred on 2 September 1958 when an Independent Air Travel Vickers VC.1 Viking (registration "G-AIJE"), loaded with two Bristol Proteus turboprop engines as cargo, and with three crew members aboard, attempted a flight from London Heathrow Airport to Tel Aviv via Nice, Brindisi and Athens.

Silene hookeri: Silene hookeri is a species of flowering plant in the pink family known by the common names Hooker's silene, Hooker's catchfly, Hooker's Indian pink, and Hooker's glandular campion.

Stanley Hooker: Sir Stanley George Hooker, FRS, DPhil, BSc, FRAeS, MIMechE, FAAAS, (30 September 1907 – 24 May 1984) was a Mathematician and jet engine engineer, first at Rolls-Royce where he worked on the earliest designs such as the Welland and Derwent, and later at Bristol Aero Engines where he helped bring the troubled Proteus turboprop, and Olympus turbojet to market, and then designed the famous Pegasus vectored thrust turbofan used in the Hawker Siddeley Harrier.

Bristol Proteus: The Bristol Proteus was the Bristol Aeroplane Company's first successful gas turbine engine design, a turboprop that delivered just over 4,000 hp (3,000 kW).  The Proteus was a two spool, reverse-flow gas turbine.  Because the turbine stages of the inner spool drove no compressor stages, but only the propeller, this engine was classified as a free-turbine.  It powered the Bristol Britannia airliner, small naval patrol craft, hovercraft and electrical generating sets.  It was also used to power a land-speed record car, the Bluebird-Proteus CN7.  After the merger of Bristol with Armstrong Siddeley the engine became the Bristol Siddeley Proteus, and later the Rolls-Royce Proteus.

Emphysematous cystitis: Emphysematous cystitis is a rare type of infection of the bladder wall by gas-forming bacteria or fungi.  The most frequent offending organism is "E. coli".  Other gram negative bacteria, including "Klebsiella" and "Proteus" are also commonly isolated.  Fungi, such as "Candida", have also been reported as causative organisms. " Citrobacter" and "Enterococci" have also been found to cause Emphysematous cystitis (Mokabberi).  Although it is a rare type of bladder infection, it is the most common type of all gas-forming bladder infections (Mccabe).  The condition is characterized by the formation of air bubbles in and around the bladder wall.  The gas found in the bladder consists of nitrogen, hydrogen, oxygen, and carbon dioxide.  The disease most commonly affects elderly diabetic and immunocompromised patients (Sereno).  The first case was identified in a post-mortem examination in 1888 (Nemati, Basra).

Bristol Phoebus: The Bristol Phoebus was an early turbojet engine developed by Bristol Engines.  It was based on the gas generator core of the Bristol Proteus.  The Phoebus was used for development but only a handful were made.  As with other Bristol engines, it took its name from classical mythology.

Wankel engine: The Wankel engine is a type of internal combustion engine using an eccentric rotary design to convert pressure into rotating motion.  In contrast to the more common reciprocating piston designs, the Wankel engine delivers advantages of simplicity, smoothness, compactness, high revolutions per minute, and a high power-to-weight ratio primarily due to the fact that it produces three power pulses per rotor revolution compared to one per revolution in a two-stroke piston engine and one per two revolutions in a four-stroke piston engine (although at the actual output shaft, there is only one power pulse per revolution, since the output shaft spins three times as fast as the actual rotor does, as can be seen in the animation below, making it roughly equivalent to a 2-stroke engine of the same displacement; this is also why the displacement only measures one face of the rotor, since only one face is working for each output shaft revolution).  The engine is commonly referred to as a rotary engine, although this name also applies to other completely different designs, primarily aircraft engines with their cylinders arranged in a circular fashion around the crankshaft.  All parts rotate consistently in one direction, as opposed to the common reciprocating piston engine, which has pistons violently changing direction.  The four-stage cycle of intake, compression, ignition, and exhaust occur each revolution at each of the three rotor tips moving inside the oval-like epitrochoid-shaped housing, enabling the three power pulses per rotor revolution.  The rotor is similar in shape to a Reuleaux triangle with sides that are somewhat flatter.

Bristol Type 118: The Bristol Type 118 was a general-purpose military aircraft, a two-seat biplane built by the Bristol Aeroplane Company in the early 1930s, powered by a Bristol Mercury radial engine and aimed at overseas markets.  The Type 120 was a Bristol Pegasus-engined variant entered into an Air Ministry competition and later used for armament tests.  Two aircraft were built.

Bristol Aquila: The Aquila was a nine-cylinder single-row radial aircraft engine designed by the Bristol Engine Company starting in 1934.  A sleeve valve engine, its basic design was developed from the Bristol Perseus.  The Aquila was never used in production, but further developments led to the Bristol Hercules, Bristol Taurus, and Bristol Centaurus.

Fiat 615: At first the model had a new petrol engine with 1395 cc and 29 kW (39 hp) at 3800 rpm to 1400 Fiat, and had a manual 4-speed transmission.  A 1.5 ton truck was newly developed, which was offered from 1951 in a flatbed and chassis for special bodies.  It was powered by the engine of the prior year featured Fiat 1400s.  The engine was already in the car Fiat 1400 was just sufficient, and with the 3.1 tons it had real trouble.  Once in motion, the Fiat 615 was indeed 80 km/hr fast, but with forced driving it had poor fuel efficiency.  There was a reason that the 1100 Fiat ELR far built until 1954.  The somewhat weaker beast of burden was, with its 1.1 liter and 28/30 PS (at 4400 rpm) a little lame, but it had fully loaded a ton to move less weight, so was more economical.  It therefore retained its loyal following who forgave its manageable liveliness out of habit, especially as it came with start-up to a peak of over 90 km/hr and thus was significantly faster than the Fiat 615 with its maximum of 78 km/hr.  With high pressure, therefore a suitable diesel engine was developed by Fiat: a swirl chamber engine (Ricardo System) based on the 1.9 liter engine for the "big" Fiat in 1900 and the new SUV Fiat Campagnola.  (This engine was a hubvergrößerte variant of the 1400 engine.)  The new diesel engine (type 305) was later also available in either sedan 1400 from 1952 in addition to the Fiat 615 N (N = Nafta = Diesel) and one year in Fiat Campagnola and Fiat.  Although the experiment of the Fiat 615 built 1.9 L gasoline engine proved to be stronger and with faster drive spurt, confined themselves to the diesel, the Type 615 N. Only Steyr in Austria until 1958 offered the Fiat 615 as gasoline, as Steyr 260 with its own 50 hp 2 L gasoline engine from the car Steyr 2000.  The Fiat 615 N was a very modern vehicle that in Italy, initially had no competition.  The export ran well at the beginning, missing, or half-hearted development left the Fiat 615 N (and especially its successor) over the years become increasingly rare even in Italy.  In Zastava in Yugoslavia, the Fiat 615 was built with a petrol engine under license.  However, not as the beginning of the Fiat, with the 1.4 L 4-cylinder engine, but with the much stronger torque 1.9 liter engine (type 105) with 47 hp at 3500 RPM, as well as in the, also at Zastava built under license, Campagnola was used.  It is unclear whether the successor (from about 1963, as Fiat 615 N1) only with the 1.9 liter petrol engine (such as 615 B) was built, with a diesel engine.

Supporting paragraphs: Stanley Hooker Bristol Proteus
Answer: turboprop