> BTW: What is the difference between Speedbrakes and Spoilers? > Some stuff i was reading about the 747 made it seem to me that > the speedbrake lever in the cockpit controls the spoiler surfaces. > ... Actually .... on the cockpit photos I found on the web (eg > www.airliners.net) there is a lever that is labeled 'speed brake'. > Its the one right next to the #1 Throttle, on the pilots side.
I haven't flown a 747, but in all the other Boeings I've flown the spoilers are divided into two groups. The Outboard few panels are called Flight Spoilers, and the inboards are called Ground Spoilers. The Flight Spoilers move automatically to assist in roll control. Roll control is provided by ailerons only until about 5 degrees of yoke movement, at which point the Flight Spoilers start helping out. I believe the purpose is to reduce adverse yaw. They do cause more drag than ailerons, which is something you have to watch out for when air refueling (in the E-3A you could back away from the tanker by just moving the yoke rapidly left and right more than 5 degrees). In any other phase of flight the effect is not noticable. The Flight Spoilers are also activated by the Speedbrake Lever, located on the left side of the throttle quadrant. This causes the spoilers to rise (in proportion to lever movement) and still assist in roll control. When the spoilers are operating in dual-use like this the roll rate increases somewhat (this effect is very noticable in the 727, less so in other models). The speed brakes don't slow the airplane down as much as you'd think. On the 737 they are not of much use. They do produce a noticable amount of noise and buffet. On the modern Boeings you can arm the Speedbrake Lever for landing. Upon touchdown all the spoilers will come up (both Flight and Ground Spoilers). Some Boeings have alternate means of activating the spoilers for landing in case the automatic system won't arm, or you forget. Dave Culp _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
