B-52 take off?

Question

I've stood and watched B-52s lift off the runway countless times.. It appears to me that the plane takes off in a 'nose down' position.

Is this an optical illusion, or is this for real?

Answer 1

Hello James -

When I was in the Air Force, I flew B52H models. There are a couple of things going on here that are not easy to see from a casual observer's standpoint:

1. The B52 has large flaps that tend to increase the lift a lot at lower angles of attack. This is good for approach, because the aircraft is designed for no-flap operation at high speed / high altitude, so you need the flaps to get a good look at the runway on final (ADDED: in other words, the flaps help you to fly at lower approach / takeoff speeds with the nose down a bit - lower angle of attack - so that you can see the runway on final and not just clouds).

2. The later model B52s (I think the Hs are the only ones still flying) were overpowered for takeoff. The turbofans that are installed on the H model have a lot more thrust than the aircraft was originally designed for. In fact, there is a "thrust gate" on the throttle quadrant that prevents the pilot from pushing the throttles too far forward during takeoff (this can be overpowered with muscle if necessary during an emergency). The net effect of this extra thrust is to provide a twisting moment on the wings that, especially on the outer wing regions, tends to twist them up and increase the angle of attack further. As a result, the wings are flying at a higher net angle of attack than the fuselage. One thing you will notice is that the tip gear at the end of the wings are in contact with the ground, but tend to lift off as the aircraft proceeds down the runway on takeoff leg. The wingtips start to fly before the rest of the aircraft does.

I don't think it takes off quite nose down, but it does look that way. It's a bit of a weird aircraft.

ADDED: You will notice that, as the flaps are raised and the speed increases, it flies more like a normal aircraft.

Answer 2

I think you will find it is an illusion and depends on when you are discussing in the take off. The B-52 has all its landing gear in the body, bicycle style, so when it rotates it only goes to the back gear and the wings rise under the lift, but if you could put a level on it you would find the body has gone to level or slightly up during the run.
This isn't a terrific video, catching the 52 well off the ground, but compare the line of the body to the horizon. The huge tail curving up helps fool the eye.
http://vids.myspace.com/index.cfm?fuseaction=vids.individual&videoid=16695808

Answer 3

Interesting observation on your part because the B-52 has consumed 20,000 gallons of kerosene by the time it has reached the end of the runway. Tack on another 5,000 gallons of burnt kerosene as that big bird attains a maneuverable flight altitude. Perhaps the pilot is fighting a massive, rapid reduction in weight to maintain stability.

Answer 4

maybe it's because the wings flap.. they move
approx 8 ft