P of F Question
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Join Date: Feb 2003
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P of F Question
Dear all, just a quick P of F question to ask.
Q1: An aeroplanes, with a c of g location behind the centre of pressure of the wing can only maintain a straight and level flight when the horizontal tail loading is :
A) Upwards <-------- Answer
B) Zero
C) Downwards
D) Upwards or downwards depending on elevator deflection.
Q2: The effect of a high wing with zero dihedral is as follows:
A) Negative dihedral effect
B) It's only purpose is to ease aeroplane loading
C) Zero dihedral effect
D) Positive dihedral effect <------ Answer.
Many thanks in advance.
Q1: An aeroplanes, with a c of g location behind the centre of pressure of the wing can only maintain a straight and level flight when the horizontal tail loading is :
A) Upwards <-------- Answer
B) Zero
C) Downwards
D) Upwards or downwards depending on elevator deflection.
Q2: The effect of a high wing with zero dihedral is as follows:
A) Negative dihedral effect
B) It's only purpose is to ease aeroplane loading
C) Zero dihedral effect
D) Positive dihedral effect <------ Answer.
Many thanks in advance.
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I concur with the answers:
1) If the CP (upward force) is in front of the CG (downward force) then the a/c will pivot down at the back.
2) The highwing = postive dihedral effect is related to sideslip. A low wing a/c is unstable in sideslip so dihedral is required to encourage stability by reducing AoA and hence lift on the lee wing (the wing pointing away from the sideward airflow). Because of the flow of air around the fuselage, with a high wing a/c the lee wing has a positive flow over the top and less airflow underneath reducing lift in that wing and stablising the bank.
1) If the CP (upward force) is in front of the CG (downward force) then the a/c will pivot down at the back.
2) The highwing = postive dihedral effect is related to sideslip. A low wing a/c is unstable in sideslip so dihedral is required to encourage stability by reducing AoA and hence lift on the lee wing (the wing pointing away from the sideward airflow). Because of the flow of air around the fuselage, with a high wing a/c the lee wing has a positive flow over the top and less airflow underneath reducing lift in that wing and stablising the bank.
