The diagram was provided by eclipseblogger with the following explanation:
"Red line is the reduced Vmo = 275 for the "A" model. The "B" model will have a Vmo = 285 (black line boundary of the envelope). The blue line is for the "A" model performance, before the drag reduction aero-dynamics mods.
The chart was publicly posted already by Bob Broders so go ahead and do with it as you wish." End Quote.
Comments on the blog have been discussing Eclipse performance on the high end--high altitude and high speed, at least however fast the Eclipse can fly.
Frankly, I can't explain the shape of the blue line curve. One would expect the max speed below 30,000 ft, yet the speed keeps increasing up to FL 350 then rapidly falls off above 350. Then again, the engine is controlled by a computer which doesn't necessarily have to follow the laws of physics.
Of more interest is the left side of the curve, the slow speed. Since early in the program, Eclipse has promoted L-39 upset training as part of the curriculum, why? Is Eclipse just being more thorough than other manufacturers or is it a genuine concern? And is the real objective recovery from high altitude stalls.
At 41,000 ft, 312 kt TAS would translate to about 150 kt equivalent (indicated) air speed. The chart reflects numbers at 5,000 lbs and a clean stall speed of about 95 kts. This 55 kt spread is pretty narrow, and gets even more narrow when the aircraft banks for a turn (think accelerated stalls) or encounters turbulence. Operating at higher weights will reduce the spread as well.
Vern like to boast how safe and fool-proof they have made the Eclipse, there is nothing to brag about here. I can't think of any other business jet operating with this small of margin.
A company in Santa Fe provides upset training in an L-39, their website provides some insight into the thrill of a high altitude stall/upset: www.jetwarbird.com/upset.html