Rolls-Royce offers BR725 for re-engined B-52

A USAF B-52H departs Guam during Exercise Cope North 13, with 3SQN RAAF Hornets in the foreground. (Defence)

Rolls-Royce has provided an unsolicited bid to re-engine the US Air Force’s remaining fleet of B-52H bombers.

The company has offered the BR725 which powers Bombardier Global Express and Gulfstream G550 business jets. The engine is designated F130 for the military versions of these aircraft, the E-11 and C-37 respectively.

If approved, the new engines would replace the B-52’s P&W TF33 turbofans on a one-for-one basis, providing increased thrust, reduced fuel consumption, and much lower maintenance requirements, and allow the type to serve for at least 30 more years.

The proposal was outlined during a September 14 media briefing by Rolls-Royce’s senior vice president of customer business, Tom Hartmann. “The F130 family of engines that we’re proposing for the propulsion modernisation is already a mostly U.S.-made product, and we’re going to take the final step in bringing the assembly and test of that to the US, should this program go forward.”

Previous re-engine efforts for venerable bomber have fallen by the wayside, either because they were too expensive, or it was thought uneconomical because the B-52 would soon be replaced. One of those efforts was an early 1990s proposal to replace the eight TF33s with four Rolls-Royce RB211 turbofans, but it was determined that, with the B-52’s wide engine pylon spacing this would provide too much asymmetric thrust should one of the engines fail on takeoff, and the aircraft’s relatively small tail and rudder would not have sufficient authority to compensate.

While the USAF does not currently have an active program to re-engine the B-52, it continues to study the idea. Following the separation of an engine from a B-52 over North Dakota earlier this year, the concept received a boost, and could ultimately result in an order for up to 650 engines.

“We believe the Air Force wants to keep the B-52 affordable and relevant for a long time to come, probably another 30 years or so, through 2050,” Hartmann said.

“They’re already investing in the aircraft. Most of the major systems except for the engines have had modernisation. Weapons, radars, comms are in the process of being upgraded.”

Comments

  1. Teddy says

    Even more amazing is that the original concept document that Boeing presented to the US forces was only 33 pages long.

    Legend goes that the Boeing design and engineer team were away from Seattle visiting the USAF brass in Ohio. They were forced to re-work and upscale a different aircraft from their initial proposal in order to encompass the then revolutionary swept wing (which the USAF initially didn’t want), and used a smaller bomber proposal that they had previously pitched to the US forces. Boeing were given one weekend to rework the proposal and pitch an intercontinental swept wing bomber.

    A small group of Boeing engineers, supported by a typist / clerk, spent the weekend doing hand calculations and building a 1:12 scale balsa-wood model in the Hotel Van Cleve in Dayton Ohio. Boeing pitched the new aircraft (the XB-52) on the Monday, and the rest is history.

    So the longest-lived aircraft still in conventional use was designed almost in haste, and the document that defined its construction and committed the USAF to a production run of 744 aircraft was smaller than an Australian Aviation magazine!

    (information courtesy of Clive Irving’s Boeing tome called ‘WIDEBODY’, and Jeanette Remak’s ‘Boeing B52 Stratofortress – Warrior Queen of the USAF’).

  2. ESLowe says

    …..although it’s interesting to remember the Basler BT 67 as well. Here is the circa 75 year old Douglas DC3 being rebuild to the point of qualifying as zero time air-frame. It’s given turbo-pro engines,new avionics, a 1.75 metre fuselage extension and 45% increase in payload. The plane is expected to have a 50 year increase in life span…and that is probably the minimum. I guess this means that every new aircraft type being an advance on the previous is not necessarily true…some aeroplanes actually find a niche that cannot be filled by a later version. “The only replacement for a DC3 is another DC3.” The B52 seems to another one; it was supposed to be replaced by the B58, the B70 and B1B’s are already preceding it into the boneyard. The idea of 8 B52 engines being replaced by 8 small engines rather than 4 big ones might get over the wire this time. What do people think?

  3. EH says

    @Teddy

    I think you’ll find it was not only the swept wing but the use of jet engines also that forced Boeing into a redesign.

    The funny thing was that Boeing had already tried to pitch the ‘idea’ of an intercontinental jet bomber to the USAF and was told not to be so experimental, so they went conservative with propellers – only to be told that that was old technology!

    100 years is a hell of a record if and when the B52 finally gets there.

  4. Peter says

    More thrust will reduce take-off distance and/or increase take-off weight. Currently some missions require a inflight refuel soon after take-off.