One reason Bones can not maintain a "near vertical" climb is that its
systems are not rated for sustained zero or negative G's for extended
periods of time. B-1B's can start a near vertical climb from over 550 KEAS.
From that speed they can maintain a near vertical climb long enough to trash
its engines due to lack of oil pressure. You will never see a Bone do an
extended inverted pass at an airshow!

You might be suprised that most of the tactical navy aircraft are limited to 10
seconds at 0 g and 30 seconds at negative g.
For an airshow that is more than enough to impress the crowd. However the blues
have unlimited neg g with no burner. If you light the burner in negative G it
will get real quiet as the engines quit. They did that stunt the first winter
practice. The solo "forgot" about the burner limit.
Sparky



Power to weight.

Maximum Takeoff Weight: 477,000 pounds (216,634 kilograms)
Weight: Empty, approximately 190,000 pounds (86,183 kilograms)
Thrust: 30,000-plus pounds with afterburner, per engine/120,000 plus
pounds
total thrust

Empty weight still exceeds the engine thrust. Add fuel, Hydralic
fluid,
water, etc. and it's weight would be about twice what it's thrust is.
The
B-1 is a remarkable bird but it has to fly. Going straight up takes
it
into
an area it's not designed to operate at. This is one bird I wouldn't
want
to be within 10 miles if it were to stall with less than 20,000 feet
involved.

As he said, for a short period of time. Start with a 500 kt pass pull
to the vertical, unload a bit and recover when airspeed reaches that
point below you don't want to go. Thrust to weight limits would apply
should you wish to accelerate vertically (or start at zero airspeed
There may be some other reason that a bone can't go vertical for a bit
but it's not lack of energy.

How about structural. As I said, it has to fly. Fighters and Missiles go
straight up. The B-1 is Fuge. The larger the bird, the less structural
punishment it can take. When the fighter goes vertical, it's airframe can
handle the pressures. Now, put enough thrust for it do sustain it more
than
a few seconds and not stall then chances are, something will break.