Actually, the Streak Eagle didn't ever fly vertically for more than a
transition. The profile, as I remember (the x's are numbers I don't
remember), was to takeoff, do an Immelman at IAS x, accelerate in level
flight to Mach x, then pull to a zoom at x degrees (or maybe at an angle
attack). I never flew this profile, but was in the F-15 Test Force when
Roger Smith did. My memory is probably faulty, but I think that my
description is fairly accurate.

Could it have accelerated through Mach 1 in vertical flight? We'll never
know. It never tried to.

Jim Thomas

Ed Rasimus wrote:

On Mon, 06 Oct 2003 19:03:36 GMT, Guy Alcala
wrote:


Ed Rasimus wrote:

snip

Now, let's put to bed this idea of accelerating through the mach
straight up. While modern jets with greater than 1-to-1 T/W ratios can
accelerate through the vertical, I sincerely doubt the mach claim. Too
much is going on with drag curves, deteriorating performance with
altitude, losses in engine efficiency, etc. I think only heavy lift
rockets accelerate through the mach in near vertical, but they
transition out of vertical fairly early in the flight trajectory and
may not be vertical either.

Oh, I don't know. While not a stock production a/c, the Streak Eagle was
certainly capable of doing so [From Jeff Ethell's book on the F-15]:


--rest of very detailed and impressive data snipped, but should be
referred to for context.---


Guy



All well and good, but the issue is could an airplane accelerate
through the mach vertically. I contend the answer is no. While the
Streak Eagle stuff is arguably the best documented and most
impressive, it involves accelerating transition into the vertical. To
truly be an acceleration through the mach vertically, it would require
establishing the vertical, then choosing max power and performing the
acceleration. IOW, pick a subsonic speed, such as 600 KIAS for the
pullup to vertical, and even allow for throttle modulation to maintain
constant airspeed through the transition to stabilized vertical at 600
KIAS, NOW accelerate from that point through the mach.

I'm still a skeptic.