The B-52 Stratofortress was first launched in April 1952 and was introduced to the U.S. Air Force in 1955. Since then, it has become the mainstay of U.S. air power. It was originally developed as a nuclear bomber to perform a key deterrent effect, but as reality changes, it only provides conventional ammunition in actual operations.
Of the 744 B-52s originally built, 76 are still in service with the Air Force and Air Force Reserve. This fleet will continue to fly after the 100th birthday of this type until 2050 and beyond. In order to reach that milestone, The new engine components will be the key to keeping these birds in the air.
Build nuclear toughness
Despite its age, the B-52 still flies regularly, Maintain the best combat readiness. Part of the reason for its long service is Buff, or the well-known “ugly big fat man”, deliberately over-designed and over-built. Created in the slide rule era, designers hope to ensure that the aircraft can cope with the pressure of high-altitude nuclear attack missions. Enough margin in the design means that despite decades of flying, the B-52 still in service still has enough structural life.
The B-52 is known for its unique layout of eight engines in four independent twin-engine pods. The bomber is equipped with Pratt & Whitney TF33-PW-103 engines and can range 8,800 miles (14,162 kilometers) without refueling. However, The last of these engines was manufactured in 1985, Continue to produce parts and maintain the engine is becoming very troublesome.
Therefore, the Air Force sought a new engine to power the remaining fleet. Indeed, this is not the first time. Before the TF33 turbofan engine was introduced in B-52H production in 1961, the first B-52 was actually equipped with various Pratt & Whitney J57 turbojet engines. Since then, the US Air Force has repeatedly investigated the prospect of engine replacement. Once before the development of the B-1 bomber, once in 1996, and both times, the project was rejected. From then on, the engine will only get older, which will cause the U.S. Air Force to open its request for proposals again in 2020.
Fly farther and smarter
To make the modification meaningful, the Air Force is seeking a replacement program that will make the engine run cheaper. These savings may come from higher reliability, easier maintenance, or simply better parts availability. The engine should also be quieter, and perhaps most importantly, more fuel-efficient. Since the development of TF33 in the 1950s, jet engine technology has made considerable progress, so the updated design can bring huge benefits to the B-52 platform.
Due to the limitations of the aging B-52 airframe, there is almost no need for greater thrust or higher speed. However, compared with the B-52, the more efficient engine can achieve a longer range and longer cruise time. The hope is to increase the range by 20-40% to 12,320 miles without refueling. This allows the B-52 to reach any point on the earth without the support of a tanker.
Another major benefit is that the new engine will be equipped with digital engine control. These systems monitor all aspects of engine health, from turbine inlet and outlet temperature to shaft speed, and almost every other aspect. When dealing with the maintenance work of the 8 engines on each aircraft, having a digital system to monitor what has failed and what needs to be changed is a huge help for the ground crew. As a bonus, any problems solved in advance will not disrupt the training plan or activity tasks. Considering the cost of these operations, this is a saving that is difficult to accurately quantify, but it can still bring dividends.
May the best engine win
The Air Force plans to order 608 new engines for its fleetWith General Electric, Rolls Royce and Pratt & Whitney are the three players competing for the contract. According to these figures, each of the 76 B-52s still in service today has 8 engines. Therefore, although four larger engines are a more typical solution on modern aircraft, the plan seems likely to stick to the eight-engine setting. Each company proposed an engine in the 20,000 lbf thrust range. General Electric introduced the CF34-10 and Passport engines, Rolls-Royce introduced the F130, and Pratt & Whitney introduced a version of the PW800. These are the smaller engines that people usually see in applications such as small regional jets or private jets.
Obviously, every company is eager to win lucrative contracts to redesign the engine for the B-52. Since 2019, Rolls-Royce has been testing their F130 competitors, Long before the plan was officially announced, at the same time General Electric with Pratt & Whitney Also busy touting their respective engines. Military procurement is a big business, and fierce battles will be carried out behind closed doors before the ink on the contract has dried up.
Ask any engineer who worked on the B-52 project in the 1950s whether their aircraft will fly in 100 years, and you are likely to make a loud laugh. However, it happened that the B-52 did a job and did a good job. Given that replacing it requires the development of expensive new aircraft, which is a problem the Air Force has been trying to solve in recent decades, it is clear that Buff will still be flying in the sky for some time. For the pilot and crew responsible for running this large machine, it is hoped that the new engine will make this job easier in the next few years.