ASQ-28 bombing-navigation system was later
modified for the Rockwell B-1A.COMPLEX CHALLENGES
A primary challenge was the choice of metals
to overcome the extreme temperatures
of up to 304°C 580°F at Mach 3. While
Lockheed opted for scarce
titanium for its SR-71,
NAA chose a sandwich
of stainless steel with
a honeycomb core for
over 100 of the XB-70’s
skin panels. Although it
was easier to work than
titanium and cheaper, it
could delaminate at very
high speeds and it was
easily damaged by mis-
handling on the ground.
The structure used some
titanium and stainless
steel for the 4,000psi
hydraulics, with many steel parts being
expensively milled from solid blocks.
Sealing the integral fuel tanks was a
constant headache, given the extreme
temperature changes. Inert nitrogen had to
be pumped into the tanks as they emptied
to prevent ignition of fuel vapours by the hot
wing structure.Escape from the aircraft at high Mach
ruled out normal ejection seats so NAA
used modified versions of the Stanley Type
B encapsulation system chosen for the
Convair B-58A Hustler and its own F-108
Rapier. The pilot and co-pilot each had
a 1,000lb (453kg) capsule that enclosedaround them with clamshell doors on
ejection at any speeds between 100 and
2,100mph (161 to 3,380km/h) and altitudes
up to 90,000ft. Blasted from the cockpit
by a 9,800lb (43.59kN) thrust rocket it was
stabilised by drogue parachutes on the
ends of telescopic booms and at 15,000ft
the main ’chute
deployed, lowering
the capsule onto
an inflated, shock-
absorbing bladder. The
occupant then stepped
out and unpacked
his extensive survival
kit. At sea, the unit
could float for up to
three days using extra
bladders.
In the cockpit, the
instruments and
controls were relatively
conventional but
vertical tape displays showed Mach number
and attitude/vertical velocity. The wing tips
could be lowered by between 25° and 65°
(increased later to 30° and 70°) depending
on speed. The areas behind the cockpit
that would have been occupied by two other
crew (navigator/bombardier and electronic
countermeasures operator) in operationalhttp://www.aviation-news.co.uk 63AV2 cruising serenely with raised wing tips. The aircraft’s unique structure made emergency recovery a real problem. Belly landings were
ruled out and pilots were told that “under no circumstances should ditching be attempted”. One glance at the huge air intake ‘box’ explains that
instruction. Terry Panopalis CollectionA chase pilot’s view of the first XB-70 at the end of a successful flight. A Valkyrie’s pilots sat 110ft ahead of the main landing gear and were over
30ft above the ground when the wheels first made contact so that it took time to develop a ‘feel’ for accurate touch-down. Parking was hampered
by poor visibility and unreliable nosewheel steering, while the forward fuselage neck flexed noticeably while taxiing. USAFPrototype AV1 returning from its first
supersonic flight on October 12, 1964 with
large areas of paint stripped away. The
1,000lb of white finish was applied thickly,
and frequently touched up after minor
ground handling damage, causing it to crack
and flake off as the aircraft’s skin flexed at
high speed. This issue was solved for AV2.
AFFTC/Terry Panopalis Collection60-65_xb70DC.mfDC.mfDC.indd 63 02/05/2018 12:35