SCAT15F From United States of America, joined Feb 2007, 402 posts, RR: 0 Posted (2 years 9 months 2 weeks 6 days 12 hours ago) and read 4450 times:
Wondering if anyone has any info on the top speed of the Lockheed Martin Orion 21 which lost to the P-8. It was essentially the same airframe as the P-3 but with 7150 hp PW150's.
The P-3 set a speed record back around 1970 of 501 mph with 4509 hp Allison T-56's. It's listed top speed was 473 mph. The Orion 21 does have a heavier MTOW, but has the same frontal area, 10,600 additional hp and much more efficient 8 bladed props.
I am guessing that the top speed for Orion 21 had to be at least 520 mph; maybe as high as 540. The same speed range as the P-8, but with far better acceleration and loiter capability.
LM never released performance data other than payload to the public that I am aware of. Anyone have an inside scoop?