In the annals of aviation history, the marriage between an airframe and its engine can make or break a machine's legacy. A new Yahoo article explores this dynamic through a list of 10 aircraft that were dramatically improved—or even redeemed—by swapping out their original powerplants for superior ones. From World War II bombers to Cold War fighters, these stories highlight how engineering ingenuity turned underperformers into legends, often at critical moments in military and civilian operations.
The list begins with the Soviet Tupolev Tu-22, dubbed the 'Backfire' by NATO, which entered service in 1962 as a supersonic bomber plagued by issues. According to the article, the original Tu-22 suffered from '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.' Despite these flaws, it found favor with some Soviet aircrew. Tupolev quickly initiated upgrades, leading to the Tu-22M variant with variable-geometry wings. However, the real transformation came with the Tu-22M3 in the 1970s, which replaced the troublesome Dobrynin RD-7 turbojet and later the NK-22 with the Kuznetsov NK-25 turbofan. This change boosted top speed from Mach 1.65 to 2.05 and extended range by a third, making it a mainstay for the Soviet Air Force and Navy.
Moving to British naval aviation, the Blackburn Buccaneer strike aircraft first flew in 1958 as a carrier-based platform with innovative 'blown flap' technology for better takeoffs and landings. But its de Havilland Gyron Junior turbojets, each producing 7,100 pounds of thrust, left it underpowered. Test pilot Dave Eagles, in an interview cited by the article, quipped about the S.Mk 1 version:
'it relied on the curvature of the earth to get airborne.'The Gyron Junior's unreliability even contributed to a fatal accident in 1970. Relief arrived with the 1962 introduction of the S.Mk 2, powered by the Rolls-Royce Spey turbofan delivering 11,000 pounds of thrust per engine. This upgrade transformed the Buccaneer into 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.' It served primarily in ground-attack roles, proving its mettle during Operation Desert Storm in 1991, before retiring in 1994.
The Douglas DC-3, an icon of 1930s air travel, transitioned seamlessly into military service as the C-47 during World War II, with over 95% of production dedicated to the war effort. Originally equipped with the nine-cylinder Wright R-1820 Cyclone producing 1,000 horsepower, most C-47s used the more powerful 14-cylinder Pratt & Whitney R-1830 Twin Wasp at 1,200 horsepower. A key variant, the C-47B introduced in 1942, featured R-1830-90 engines with a two-speed supercharger for high-altitude operations. This was vital for the China-Burma-India supply routes, enabling full payloads over 15,000-foot Himalayan passes. Post-war, the Super DC-3 experimented with uprated Wright R-1820 Cyclones at 1,475 horsepower, achieving a cruise speed of 250 mph compared to the original 224 mph. Though not commercially successful due to airframe modifications, the U.S. Navy adopted 100 conversions as R4D-8 and later C-117D variants.
Helicopters also benefited from engine evolutions, as seen with the British Westland Lynx, which debuted in the 1970s with exceptional maneuverability from its semi-rigid titanium rotor head and twin Rolls-Royce Gem turbines totaling around 2,000 horsepower. A Lynx marked G-LYNX set a helicopter world speed record of 216 knots (400 km/h) in 1986, a mark it still holds. As the design aged and added weight from avionics and defenses, performance waned, especially in hot, high-altitude environments like Afghanistan and Iraq. Rather than derating components, Westland opted for the CTS800 turboshaft from the canceled U.S. RAH-66 Comanche program—a Rolls-Royce/Honeywell joint venture. Weighing the same as the Gem but producing 1,563 horsepower (35% more power), it powered the Lynx Mk9A to handle full fuel loads and maintain level flight after engine failure in combat zones.
The Westland Wessex, a license-built version of the Sikorsky S-58, marked a bold shift from piston to turbine power in the mid-1960s. The original S-58's Wright Cyclone piston engine, a World War II holdover at 1,200 horsepower, was heavy and vibration-prone. Westland replaced it with the lighter Napier Gazelle turboshaft at 1,450 horsepower, improving the power-to-weight ratio from 1.03 hp/lb to 1.31 hp/lb and eliminating the need for cooling fans and clutches. Subsequent models, like the Wessex Mk 2 and 5, adopted twin Rolls-Royce Gnome engines at 1,350 horsepower each. This allowed one-engine-inoperative performance comparable to the single-engine predecessor's full power. While the gearbox limited continuous output to 1,550 horsepower, the upgrades raised the out-of-ground-effect hover ceiling from 5,500 feet in the H-34A to 10,000 feet at 5,230 kg (11,506 lbs) in the Mk 5, enhancing safety and versatility.
Aerial refueling transformed with the Boeing KC-135 Stratotanker, which entered service in the 1950s with four Pratt & Whitney J57 turbojets. Early turbofan attempts, like the Rolls-Royce Conway, offered only marginal gains, so retrofits were deferred. By the 1980s, technology had advanced sufficiently for major overhauls. An initial upgrade to Pratt & Whitney TF33 engines on 157 aircraft boosted fuel offload and range by 20%. The pivotal KC-135R model, introduced mid-decade, fitted the CFM56 turbofan with 22,000 pounds of takeoff thrust—a 60% increase over the J57. Combined with airframe tweaks, this allowed a higher maximum takeoff weight, 30% more fuel offload, and a 60% greater mission radius. Improvements in takeoff performance, noise, and emissions extended the tanker's service life, supporting U.S. Air Force operations worldwide.
World War II fighters exemplify engine swaps' wartime impact, starting with the North American P-51 Mustang. In 1940, Britain urgently needed fighters, prompting North American to design the P-51 instead of licensing the Curtiss P-40. Its sleek, low-drag airframe with a retractable tailwheel made it fast and maneuverable, but the Allison V-12 engine faltered at altitude. The solution: the Rolls-Royce Merlin V-12, license-built by Packard in Detroit. This pairing, considered by engineers on both sides of the Atlantic, elevated the P-51 to escort bombers across Germany, securing Allied air superiority. Its range allowed attacks on opportunistic targets, contributing decisively to victory in Western Europe.
Italy's Macchi fighters faced similar challenges early in the war. The C.200, powered by a Fiat radial at 870 horsepower, was outclassed by Allied planes with 1,000-plus horsepower engines. Italian doctrine favored radials over inlines, leaving the Regia Aeronautica vulnerable. Desperate, they licensed the German Daimler-Benz DB 601 V-12 for the 1940 C.202 Folgore, which added an enclosed cockpit for streamlining. Topping 372 mph with superior climb and agility, it outperformed Spitfires, Bf 109s, and North African foes like Kittyhawks and Hurricanes. Evolving to the DB 605-equipped C.205 Veltro, it became one of the war's finest fighters.
The Grumman F-14 Tomcat, immortalized in the 1986 film Top Gun, struggled with its inherited Pratt & Whitney TF30 engines from the canceled F-111B. Designed for the low-maneuver F-111, the TF30 was underpowered, thirsty, smoky, and unreliable for carrier dogfights. The TF30-P-414A variant improved reliability, but thrust remained inadequate. In the 1980s, the General Electric F110-GE-400 turbofan provided the needed punch, turning the Tomcat into an 'awe-inspiring machine' with unmatched performance for its advanced weapons and sensors. The F-14 retired from U.S. service in 2006 but continues with Iran's air force, a remnant of pre-revolution ties.
Topping the list is the Avro Manchester to Lancaster transition, a RAF Bomber Command saga. Of 193 Manchesters, 123 were lost, earning it a grim reputation due to two unreliable Rolls-Royce Vulture engines. Frequent single-engine failures proved disastrous, with serviceable aircraft rarely exceeding 31 before February 1942. Issues included in-flight fires and hydraulic fluid blinding crews. Introduced in November 1940 and phased out by 1942, the airframe's potential shone when re-engined with four Merlin V-12s, birthing the Lancaster. Though more than just an engine swap—the prototype was a converted Manchester—the Lancaster became a cornerstone of the strategic bombing campaign.
These examples underscore a broader truth in aviation: engines are the heart of flight, and upgrades can redefine destinies. From extending ranges over mountains to enabling supersonic dashes, such innovations saved lives and won wars. As modern fleets age, similar retrofits—like those on the KC-135—suggest this pattern persists, ensuring relevance in an era of evolving threats.
Looking ahead, the lessons from these aircraft influence today's designs, where efficiency and power balance sustainability demands. Programs like the canceled Comanche's engine repurposing for the Lynx show how past investments yield future gains. Aviation historians and engineers continue to study these evolutions, reminding us that greatness often follows a pivotal change.