Horizontal Stabilizer Shape
Hello all,
Just a quick question about something I'm trying to find out.
Are horizontal stabilizers on most transport aircraft symmetrical aerofoils?
I'm reading about negatively cambered aerofoils on the tailplane, but I'm confused as to how this would work in trying to produce an upward force on the tailplane should the aircraft have its aerodynamic centre situated fwd of the centre of gravity.
Surely with a negative camber, in essence being an upside down wing, means it will only produce a force going down, regardless of its angle of attack. How would this produce an upwards force should the AC be fwd of the CoG?
The only situation I can imagine in which the stabilizer may produce an upward and downward force is if it is symmetrical, in which case a + AoA will give an upward force and a - AoA will give a downforce.
I'm thinking along the line of having a negatively cambered stabilizer at +4 degrees AoA will mean it won't give any downforce, the same way a positively cambered wing stops giving lift at -4 degrees AoA ... but does pushing it to +5 degrees mean it will start to give an upforce?
I appreciate any help
Thanks