Rockwell B-1 Lancer
Already in the mid 1960s the US military were looking for a high speed aircraft that could fly at low altitudes, but had a longer range and higher payload as the General Dynamics FB-111 and Convair B-58. To search took quite a long time as some in the government were in favour of relying mostly on ballistic missiles in combination with FB-111s. But finally Rockwell was awarded a contract late in the 1960s to develop the B-1. After four prototypes had flown the programme was put on ice again in the mid 1970s, before being reactivated early in the 1980s and finally put in series production.
The B-1 Lancer has variable sweep wings, allowing low-level flights at high speeds, and enabing a low speed for landing. Under the fixed parts of the wings are two pairs of engines, fed by wedge shape air intakes (when viewed from below). In between the engine pairs are the main landing gears with four wheel bogeys. The nose gear has two wheels. The shape of the fuselage is typical, with a relatively narrow centre fuselage; the front - near the cockpit - and rear have a larger diameter, especially when viewed from the side. This is due to the blended wing-body shape. Small vanes below the nose help smoothing the ride at low altitudes but high speeds. Finally, the B-1 has a cruciform tail with a curved leading edge of the vertical stabiliser, from the long dorsal fin to the top of the fin.
The different versions of the B-1 can be recognised by looking at
- the shape of the air intakes
- the shape of the tail cone
- the shape of the bullet fairing between horizontal and vertical stabiliser
- the shape of the overwing fairing, including the part between the exhausts
This was the original B-1, developed in the 1970s. It was intended to fly faster than the later B-1B. Therefore the air intake have a different shape: they are variable on the inside, to enable slowing down the air at all speeds. When viewed from the side, the shield between the two engines in the pair is perpendicular to the wings/fuselage. Additionally, the tail cone and bullet fairing behind the horizontal stabilisers are pointed. Finally, the fairing between the two engine exhausts on each side has sharp corners. View the photo below to see what is meant.
A full view of a B-1A prototype. Although the photo is a bit small you can still clearly see that the shield between the two engines is perpendicular to the underside of the wing/fuselage fairing. (photo: USAF/WikiMedia)
From this viewpoint you can clearly see the pointed tail cone of the B-1A. Also note the fairing between the exhausts has sharp corners. (photo: Clemens Vasters/WikiMedia)
When the B-1 programme was revived in the 1980s, the modified version was designated B-1B. The air intakes are now fixed, but better visible is that the shield between both intakes has a angle of about 45 degrees with respect to the underside (see photo). The tail cone and bullet fairing have become more blunt. Last but not least the overwing fairing has a different shape. The part between the exhausts has a different shape, with less sharp corners. See top photo for more details.
Confusion possible with
The Soviet/Russian counterpart of the B‑1 is in many aspects a copy of the American aircraft. There are still many differences though like the shape of the nose/cockpit. Also the main gear has six wheels per leg and the nose gear retracted rearward. The leading edge of the vertical fin is les curved.
Like the B‑1 the Tu‑22M2/M3 has a similar size and has variable sweep wings, but for the rest it is quite different. The wedge shaped air intakes of the Tu‑22 are at the side of the fuselage, feeding only two engines. The main landing gear has six wheels per leg, like the Tu‑160. The tail has a conventional shape.
General Dynamics F-111
The F(B)-111 is much smaller than a B‑1, although used for a similar task. The 111 has two engines and the air intakes under the wing leading edge extensions have the shape of a quarter circle. The variable sweep wings are placed high on the fuselage. The main gear has single wheels.