Spoiler and speed brake. But where is the difference?

Question

Spoiler and speed brake. But where is the difference?

Answer 1

I'm type rated in a newer model jet which uses some of the panels as roll spoilers, others of them for partial speed brake deployment, and all of them for full speed brake deployment. As roll spoilers, they deploy automatically along with the raised aileron. The speed brakes are manually selected (with a handle) partially to a detent, then through the detent to full deployment (all panels fully deployed). The EICAS/MFD display indicates which panels are deployed. (I have flown other jets which had both upper and lower speed brake panels, i.e., which deployed both above and below the wing.)

Answer 2

Spoilers destroy lift, speed brakes create drag.

Answer 3

The difference is the amount of deployment.  For example, the airliner I fly had inboard and outboard spoiler panels driven by the left and right hydraulic systems.  They both deploy when I pull the handle.

When in flight, the handle is pulled straight back and the panels are deployable up to 30 degrees.  This is the "speed brake" which allows a steeper descent at the same speed.

When landing (prior to), the handle is pulled up to the "armed" position and upon wheel spin-up at touchdown, the "spoilers" (as in spoiling lift) deploy to a full 60 degrees.

Sometimes you might look outside and see the panels rising in flight when the aircraft is turning, this is roll augmentation and the panels will rise referencing the deflection of the yoke past 5 degrees of center.

Answer 4

Spoilers and Speed Brakes both involve the same components of an aircraft, consisting of panels whose trailing edge is forced upwards (usually by hydraulics) into the airflow passing over the top of a wing.

Spoilers are used to assist the ailerons during turns on many high performance aircraft. In this use, the spoilers will only move a small amount, and only on one wing at a time. Not only do spoilers kill the lift, causing the inside wing to drop; but they also create drag to counteract the effects of adverse yaw. Many aircraft have both inboard and outboard spoilers. The outboard spoilers operate at low speeds only. The inboard spoilers become active at higher speeds, and the outboard spoilers are deactivated in order to reduce the wing bending forces towards the wingtip.

As mentioned by the other poster, spoilers are also used during landing. In this use, all spoilers (inboard and outboard) on both wings will simultanously fully deploy on landing in order to: destroy lift to keep the aircraft's weight on the wheels to assist in frictional wheel braking, and also to create aerodynamic drag to further assist in deceleration.

Speed Brake is the term for the partial but symmetrical use of the spoilers in flight. In fact, the handle in the cockpit is marked exactly that: "Speed Brake", even though it is activating the spoilers. In this use, the spoilers on both wings deploy a moderate amount. This is done in order to kill the lift and increase the drag on both wings in an equal amount. As mentioned before, the use of the Speed Brake in flight is mainly done to increase the rate of deceleration during speed changes, or to increase the rate of descent during altitude changes when speed must remain constant or decrease simultaneously with the descent.

Aircraft like the B-52 and MU-2 do not have ailerons for roll control. They use only spoilers for roll control, and these flight controls have been renamed "spoilerons".

Answer 5

SPOILERS: this is the actual name of the panels which rise from the top of the wing (spoiler panels). Their main purpose is on touchdown, where all spoiler panels open to their maximum angle. This is to "spoil" (hence the name) the lift on the wing to make sure the plane stays firmly on the runway. This also increases the effectiveness of the brakes by putting more downforce on the wing.

SPEEDBRAKE: the speedbrake is used in the air by pulling a lever in the cockpit. It uses the same panels (the spoiler panels), but not all of them. Also, they don't open to their maximum angle. It's main purpose is to slow the plane down, or to increase the descent rate (or both).