Why not CFM's?

What the hell are you asking?

Assuming you're wondering why they don't have CFM motors?

Beats me.  I don't build airplanes.

Edit:  What do they use?  TF33?  By Pratt & Whitney?

Edit: They do use TF33s.  There was talk of upgrading to some Rolls Royce.
www.answers.com/main/ntquery?method=4&dsid=2222&dekey=B-52+Stratofortress&gwp=8&curtab=2222_1&linktext=%3CSPAN%20class%3Dhl0%3EB-52%3C%2FSPAN%3E%20Stratofortress

  It would cost way to much to retrofit CFM's on a B52. Assuming the A/C would loose four motors the whole pylon would have to be re-engeniered. Some 707 airframe have CFM motors on them.  I think the military would rather have a upgraded Avionics/weapons platform than an Engine upgrade

Been studied to death.

At the time (late 80's early 90's) there were enough complete TF33 engines and spares left to keep the fleet flying for another 12-17 years.

Boeing submitted a proposal to re-engine them with Rolls Royce engines, the RB.211-535E4-B turbofan.

It's not just a straight forward engine swap, the pylons would need to be modified/remanufactured, the wings would need to be strengthened and the flight procedures would need to be modified.

I think that if the USAF wants to end the life of the B-52 at 2025 it is going to need to renegine a "few" of them.

An unsolicited proposal for reengining 94 aircraft in the B-52 fleet was submitted to the Air Force by Boeing North American, Inc. in June 1996. Boeing proposed modernizing the B-52 fleet by replacing the current TF-33 engines with a commercial engine through a long-term leasing agreement, and providing fixed-cost, privatized maintenance based on the number of hours flown each year. Boeing's proposal included modernizing the B-52 fleet by replacing the TF-33 engines with the Allison/Rolls commercial RB-211 engine through a long-term leasing agreement and providing a fixed-cost, privatized maintenance concept through a "power-by-the-hour" arrangement. Boeing initially projected reengining cost savings of about $6 billion, but later revised the projected savings to $4.7 billion to reengine 71 B-52s. An Air Force team formed to study Boeing's proposal analyzed the lease and purchase alternatives and concluded that both options are cost prohibitive compared to maintaining the existing TF-33 engines. The General Accounting Office estimated that Boeing's unsolicited proposal to reengine the B-52 fleet would cost the Air Force approximately $1.3 billion rather than save approximately $4.7 billion as Boeing projected.

Not to hijack,but back in the early 80s,there was also talk of refiting the rest of the DC-8 fleet with CFMs(the DC-8 airframe is very robust,damned near unlimited)however,the cost was prohibitive,and as a result,only 110 were done. Falling fuel prices and cheap hush-kits were the major reason.(would loved to have seen a -50 series done!)

Quoted: Not to hijack,but back in the early 80s,there was also talk of refiting the rest of the DC-8 fleet with CFMs(the DC-8 airframe is very robust,damned near unlimited)however,the cost was prohibitive,and as a result,only 110 were done. Falling fuel prices and cheap hush-kits were the major reason.(would loved to have seen a -50 series done!)

I LOVE the Super-8 with CFM56's!


I did manage to get one flight on this Navy EC-24 (DC-8-54F).



No CFM's though.