Top 10+ aircraft made great by a new engine
A great aircraft is the civil (or military) partnership of a good engine and good airframe.
And sometimes a separation is necessary to make way for a more appropriate partner. Many great aircraft have been held back by a combination with inappropriate or inferior engines. Here are 10 power-hungry flying machines that finally got the engine they deserved:
10: Tupolev Tu-22/Tu-22M ‘Backfire’
The Soviet Tupolev Tu-22 bomber is the David Bowie of aircraft, reinventing itself with such radical vision that you’re left to ponder what exactly is left of the original. Little wonder the supersonic bomber required reinvention really when you consider how awful the original Tu-22 was.
The original Tu-22 was abysmal in almost every sense. Appalling unserviceability, a wing that allowed aileron reversal at high deflections – a tendency to pitch up and strike its rear end on landing, disappointing range and poor pilot view were only some of the problems. Bizarrely, it still proved popular with many, perhaps overly loyal, aircrew.
10: Tupolev Tu-22/Tu-22M
The Backfire served with the Soviet air force and navy, and the design bureau, Tupolev, was under pressure and didn’t take long to plan a major upgrade to this stinker, starting work the very same year the type entered service, 1962. Ten years later a virtually unrecognisable aeroplane, with different (and variable geometry) wings and a host of other modifications, entered service.
Despite all the radical changes, it didn’t get a new model number, just the addition of an M. But it was still a turkey. The terrible Dobrynin RD-7 turbojet had been replaced with the newer, but also terrible, NK-22. The most important change didn’t happen until the Tu-22M3 update, which introduced the Kuznetsov NK-25 turbofan. With this and other refinements, the top speed leapt from Mach 1.65 to 2.05 and its range was increased by a third.
9: Blackburn Buccaneer
Blackburn Aircraft Limited is famous for making some planes not as good as they should have been, and the initial Blackburn Buccaneer was no exception. The aircraft was a British carrier-based attack aircraft that first flew in 1958. It was a structurally strong design with the innovative use ‘blown flap’ harvesting and steering diverted engine thrust to improve its take-off and landing characteristics.
But the innovative Buccaneer S.Mk 1 was powered by the unreliable de Havilland Gyron Junior turbojet, and was a weakling. It was underpowered, as test pilot Dave Eagles once joked in our interview with him: “it relied on the curvature of the earth to get airborne.”
This was solved when the S.Mk 2 was introduced in 1962, powered by the Rolls-Royce Spey turbofan. Replacing the Gyron Junior of 7,100 pounds-force each with the 11,000 lbf Spey was a masterstroke. The Gyron Junior would later be held responsible for a terrible accident in 1970.
The result was a superb low-level aircraft with a long-range (longer even than the Panavia Tornado), a virtually indestructible construction and a rock-steady low-level ride. The type spent much of its life as a ground-based attack aircraft, and proved its worth in Operation Desert Storm, in 1991. It remained to the end of its life - in 1994 - a potent weapon.
8: Douglas C-47/DC-3
The DC-3 was an airliner developed in the mid-1930s. At the beginning of the second world war, it was adapted (with minor modifications) into a military transport aircraft and (predominately) designated the C-47. Over 95% of the airframes built were these military versions.
During the decade of C-47 production, several engine variants were used, without significant changes to the type or size of the engine. The original DC-3 was powered by the 9-cylinder Wright R-1820 Cyclone 9 producing 1000 horsepower. The C-47 mainly used the 14-cylinder Pratt & Whitney R-1830 Twin Wasp which produced 1200 horsepower.
Roughly one-third of the US-built aircraft was the C-47B variant. This aircraft used Pratt & Whitney R-1830-90 engines with a high-altitude two-speed supercharger. This 1942 modification was critical for the China-Burma-India supply routes and allowed the aircraft to carry a full payload over the 15,000-foot mountain passes.
The Super DC-3 was developed post-war using 9-cylinder Wright R-1820 Cyclones producing 1475 horsepower. While not commercially viable due to the extensive airframe modifications required, the US Navy converted 100 aircraft, and they were designated R4D-8 and later the C-117D. This variant had a cruise speed of 250 mph, up from 224 mph for the original C-47.
7: Westland Lynx
The British Westland Lynx burst onto the scene in the ‘70s boasting previously unseen levels of manoeuvrability for a helicopter, thanks to a semi-rigid rotor head hewn from a solid block of titanium and two Rolls-Royce Gem gas turbines. The 2000-odd horsepower from two tweaked Gem 60s helped drive one Lynx (registration G-LYNX) to a helicopter World Speed Record of 216 knots (400 km/h, M0.32) in 1986, a record which it still holds today.
Unfortunately, as aircraft age they tend to put on weight – the odd defensive aids suite here, an infra-red camera there – and suddenly you’re underpowered. A process made worse you find yourself committing the classic blunder of getting involved in a land war in parts of the world, where the air is hotter and thinner; both factors count against engine and rotor blade performance.
There are two ways out of this inevitable decline: set higher limits for the engines and gearbox to run at, and accept the parts won’t last as long. Or you could try finding a new engine. Handily for Westland, the Light Helicopter Turbine Engine Company (LHTEC) had just want they needed left over from the RAH-66 Comanche programme, a US stealth helicopter that was cancelled in 2004.
The CTS800 engine (developed by a Rolls-Royce/Honeywell joint venture), despite weighing the same as the Gem, produces 35% more power with a max output of 1563 hp, which was only 300 hp less than the maximum continuous power you could get from two Gems. This massively improved the hot and high performance of the Lynx Mk9A introducing novel concepts such as taking a full fuel load and maintaining level flight after an engine failure in Afghanistan or Iraq.
6: Westland Wessex
The Sikorsky S-58 was powered by a Wright Cyclone piston engine. This rather dated engine had been earlier used on several second world war warplanes. In the mid-1960s, Westland hit on the idea of licence-building the American S-58, with one crucial difference. Out went 1200 hp of high-octane, war-winning reciprocation and in came the Napier Gazelle. This was a move of some genius.
Although the Gazelle was down on horsepower compared to the Cyclone, 1450 hp to 1525 hp, it was a good deal lighter. This gave it a power-to-weight ratio of 1.31 hp/lb to the Cyclone’s 1.03 hp/lb. Unlike the Cyclone the Gazelle didn’t need a heavy clutch and fan to keep air flowing over its cooling fins, nor did it vibrate like a tumble dryer full of bricks.
The next step was going from one to two engines. Two Rolls-Royce Gnome engines were substituted for the Gazelle. These provided 1350 hp each giving the Wessex Mk 2 and 5 almost the same performance with One Engine Inoperative (OEI) as the Mk 1 achieved with everything working.
This extra power didn’t significantly alter the basic performance of the Wessex, as the main rotor gearbox wasn’t designed to take much more than 1550hp continuously. However, it did allow it to take this basic performance to new places. The H-34A had an out-of-ground effect hover ceiling of 5500 feet, whereas the Wessex Mk 5 had one of 10,000 feet at an all-up mass of 5230kg (11,506 lbs). The new helicopter was far safer, smoother and spritely.
5: Boeing KC-135 Stratotanker
A turbojet, the simplest version of a jet engine, passes all the engine airflow through the compressor, burner and turbine. By contrast, later turbofan engines have a ducted fan at the front of the engine, and only a portion of the airflow goes through the core of the engine. This allows better optimisation of the engine and provides better fuel and weight efficiency, lower noise and less pollution.
The KC-135 originally used four Pratt & Whitney J57 turbojets. The first production turbofan engine, the Rolls-Royce Conway, entered service soon after the KC-135. However, its performance was only marginally better than a turbojet, and an engine retrofit at that time was not justified. Turbofan technology continued over the next twenty years, and it was finally time for an upgrade in the 1980s. And what an upgrade it was...
An initial upgrade to the Pratt & Whitney TF33 engine was performed on 157 aircraft. This increased the tanker performance (fuel off-loaded and/or mission range) by 20%. The more significant upgrade came in the mid-1980s with the KC-135R model. This upgrade used the CFM56 engine and was applied to a majority of the fleet. The CFM56 produces 22,000 pounds of take-off thrust, a 60% increase over the J57 engine.
This, along with a few airframe upgrades, allowed for a maximum take-off weight increase, and a significant increase in aircraft performance. Compared to the original A model, the R model can offload nearly 30% more fuel, and its mission radius is increased by 60% or more, depending on fuel offload. Take-off field performance, noise, and emissions are also improved.
4: North American Mustang
In 1940, Britain was desperate for large numbers of modern fighter aircraft. The US company North American Aviation was approached and asked to build Curtiss P-40s. They believed they could create a far superior design and in response created the P-51.
The resultant aircraft combined all the latest innovations in aerodynamics to create an exceptionally ‘clean’ low-drag machine. Everything about was designed with low drag in mind, down to the then-novel fully retractable tailwheel. The P-51 was fast, extremely long-ranged and manoeuvrable. But its original Allison V12 engine was less than stellar at medium and higher altitudes.
Pairing the most aerodynamically advanced airframe in creation with the best aero-engine in the world, the British Rolls-Royce Merlin V12, was a match made in heaven. An excellent low-level fighter became a superb all-round fighter. Some British historians may claim the re-engining was an entirely British idea, but several engineers in America had also considered this a happy marriage. The Merlin engines for the P-51 were mostly built by Detroit motor giant Packard, under licence.
The North American P-51 Mustang became a war-winning weapon, able to stay and protect bombers throughout their entire mission. The American fighter’s massive range allowed them free rein over Germany, taking out targets of opportunity once their escort missions were over. The superb P-51 played no small part in the Allies achieving air superiority over Western Europe.
3: Macchi C.200-C.202/205
When the Italian air force took the C.200 to war, it proved utterly and dangerously outclassed. Its Fiat radial engine generated an unimpressive 870 hp, leaving it underpowered compared to Allied opposition boasting 1000 hp or more powerplants. Poor thinking in the 1930s had led Italy away from adopting powerful inline engines, in favour of uncomplicated radials; in reality, all this thinking had got the Regia Aeronautica was a fighter force too slow to survive.
Aware of the mauling Italian fighters were receiving, Italy's General Staff frantically turned to Alfa Romeo and Fiat begging for radials of greater power, but none were forthcoming. In desperation, they turned to their German allies to request licence-production rights for the inline Daimler-Benz DB 601 V12, as used by the formidable Bf 109 and Bf 110.
The German engine had a far smaller frontal cross-section than the Fiat engine allowing for greater streamlining and far more power. A 601 was fitted to a C.202, and the machine was also given an enclosed cockpit. Thus the ‘Folgore’ was born in 1940, and it was a great machine.
With a top speed of 372mph, it was as fast or faster than contemporary Spitfires and 109s – and its climb rate was spectacular, and it was also agile and of extremely rugged construction. In North Africa, the Folgore proved a decisively superior fighter to the Kittyhawks, Tomahawks, Hurricanes and Fulmars it faced. Further evolved, and with the addition of the DB 605 it became the C.205 Veltro, one of the best fighters in the world.
2: Grumman F-14 Tomcat
The Grumman F-14 Tomcat is famous as the star (along with Tom Cruise) of the 1986 Top Gun movie. It was a large and capable aeroplane, the ultimate in Grumman’s series of tough fighters able to operate from aircraft carriers. It retired from US service in 2006, but today remains in service with the Islamic Republic of Iran Air Force; Iran and America were once friends, in the 1970s, when the planes were purchased.
The F-14 inherited a curse from the fat wheezy abortive F-111B it was made to replace, the lamentable TF30 engines. The TF30 story goes back even further, as it was originally conceived for the Douglas F6D Missileer a loitering ‘missile-truck’ of an aircraft which never flew.
The TF30 proved passable for bombers looking to move extremely quickly at low-altitude without the violence of extreme dogfight manoeuvring and found gainful employment with the F-111. But, as a fighter engine it was terrible. Weak, thirsty, smoky, unreliable, pilots of the otherwise excellent Tomcat had to learn to manage these untrustworthy engines.
The TF30-P-414A solved the reliability issue to some extent but the Tomcat was still underpowered. Eventually, the Tomcat got the engine it needed, with the fitment of the excellent General Electric F110-GE-400. The new Tomcat was an awe-inspiring machine, with performance to match the world-class weapons and sensors it carried.
1: Avro Manchester/Lancaster
Of 193 Avro Manchesters that saw service, 123 were lost. It was with good reason that assignment to the Manchester was seen by many in RAF Bomber Command as a death sentence. Mournfully underpowered by two unreliable Vulture engines, loss of power in one engine - an all-too-common event - was often disastrous.
Up to February 1942, the average amount of serviceable Manchesters at once never exceeded 31. When the Manchesters were not grounded or catching fire in flight, there were cases of hydraulic fluid spraying into the cockpit and temporarily blinding the crew.
