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Flight control surfaces and how to use them

CrashRecovery

I'm a care bear...Really?
Mentor
#1
Ok some one explain it for me. I understand how elevators, ailerons and flaps work but how does a rudder mix in? Like when your turning to the left what way do you need to turn it to finish the flight?
 

pgerts

Old age member
Mentor
#2
It is not easy to explain unless you specify a plane you fly.
Many planes does not have any rudder at all like many delta fighters with flat profile.
Some planes does only have rudder (no aileron) like many gliders with a lot of hedral and dihedral.
On a flat profile indoor foamie you can think of the rudder as a steering wheel on a drift-car. It just turns the model around without making it go up or down or roll.
On a plane with a lifting profile and a lot of hedral (V-form) the rudder also makes the outher wing go faster than the inner wing making it lift (like an aileron) and you have to give a little up elevator to compensate for the reduced lift from the wing compared to when it is leveled.
Some planes (like CUB) need rudder together with aileron not to hang with the tail in the turns.
Many times you will need rudder to compensate for wind when landing in cross wind.
 

pgerts

Old age member
Mentor
#4
So like on the spitfire if I was to turn left, pull a little elevator, why would i need a rudder?
You are right.
Most dogfighters (combat 1:12) do not have any rudder - just a fin.
I do not have any rudder on my Vought Windicator and several other planes like the FUNBAT.
On the other side - i could not do any fun flying with my Vision Aire without the rudder.
 

Cooley

Father/Son Team
#5
The Spitfire had hedral (the wings angled up) this gives it very little need for rudder in flight. However, when trying to land or take off (especially in windy conditions or if you have and over sized motor) you will need a little rudder to track straight on or close to the ground. You can also use it for certain airial maneuvers like the split-S and evasive roll.
 

Washout

Junior Member
#6
Rudder gives you yaw... like sitting on an office chair and spinning round.

Rudder helps you counteract something horrible called adverse yaw. If you can believe the rule where you don't get something for nothing then you will understand that when you use ailerons to roll, the wing going up is doing this because the aileron is making the wing generate more lift. Due to the above rule, more lift means more drag. So, if you roll left, whilst your ailerons aren't neutral, your aircraft will want to yaw right. To compensate, use a bit of left rudder whilst you have the aileron left of neutral. right aileron needs right rudder... this is called coordinated controls.

Most powered aircraft can live without people coordinating their controls as the motor effectively pulls the aircraft round the way you want it to go. However, better pilots will use some to make the whole flying that bit smoother.