hat
Tout KC-135 a te orijinalman ekipe ak motè turbo ak Pratt & Whitney J-57-P-59W. Nan 1980s yo, pwogram nan premye modifikasyon amelyore gaz yo 157 ak Pratt & Whitney motè a turbofan TF-33-PW-102. Pote tank la modifye, ki deziyen KC-135E a, te 14% plis gaz-efikas pase KC-135A la. Dezyèm pwogram nan modifikasyon modèn avyon 500 ak nouvo CFM56. Pote tank la modifye, ki deziyen KC-135R (KC-135A modifye oswa E) oswa KC-135T (modifye KC-135Q), se 25% pi efikas gaz pase ak motè yo anvan yo.
eng
All KC-135's were originally equipped with Pratt & Whitney J-57-P-59W turbojet engines. In the 1980s the first modification program retrofitted 157 tankers with the Pratt & Whitney TF-33-PW-102 turbofan engine. The modified tanker, designated the KC-135E, was 14% more fuel-efficient than the KC-135A. The second modification program retrofitted 500 aircraft with new CFM56. The modified tanker, designated KC-135R (modified KC-135A or E) or KC-135T (modified KC-135Q), is 25% more fuel-efficient than with the previous engines.