Prop Plus Jet Aircraft

Its true about the C-123K, We were heading back to Westover AFB and decided to see how fast the old "Thunder Pig" could go. The best we got was 220 knots I.A.S. We were burning about 1,000 lbs of fuel ever 10 minutes!! The weird thing was when you trimmed the aircraft out for level flight, it seemed to like to fly in a nose down attitude.

Probably, among the most widely known of them (if not counting the B-36D-F-H-J) were the KB-50J/K (a total of 136 had been converted), and some later - the KC-97L (total 81). They had four R-4360 piston engines with addition of a pair of J47 turbojets. Tankers had received such a low-cost upgrade in order to raise their speed and altitude of level flight during refueling modern jet-powered aircraft.
Also, aged tankers that have had forced to operate on heavy-laden take-offs, unavoidably had need in such improvement of their capabilities.
They were an interim substitute for forthcoming KC-135. Also, as I presume they had been a some alternative for the cancelled B-54's eventual derivative - the hypothetical KB-54.