1. Process of defining external geometry of an A/C is ___________
a) lofting
b) drafting
c) drawing
d) flutter
Explanation: Lofting is defined as the process in which external geometry of an A/C is defined. It is nothing but the mathematical modelling the outer layer of the aircraft. Flutter is related to control surface. Drawing and drafting are related to each other.
2. Production lofting and simple lofting both are same phenomena.
a) True
b) False
Explanation: Lofting is the method for defining external geometry of the aircraft. Production lofting is most detailed type of the lofting. It is used to provide exact and accurate mathematical model of the body
3. Determine the corrections or otherwise of the following assertion [A] and reason [R]:
Assertion [A]: In modern A/C, we generally do not use spline lofting.
Reason[R]: Spline lofting is drawn through connecting different known points via spline line.
a) Both [A] and [R] are true and [R] is the correct reason for [A]
b) Both [A] and [R] are true but [R] is not the correct reason for [A]
c) Both [A] and [R] are false
d) [A] is false but [R] is true
Explanation: Now, in modern days we generally do not use spline lofting due to some disadvantages. Spline lofting requires more trial and error in order to achieve the smoothness as per requirement. Spline lofting is done by connecting different points via spline line.
4. What is conic lofting?
a) Lofting done by using various conic curves
b) Lofting done by using various circle only
c) Lofting done by using various triangle curves only
d) Lofting done by using various square curves only
Explanation: When lofting is done by using conic curves then, it is termed as conic lofting. Conic lofting may include only circles but it is not mandatory that if conic lofting is mentioned then, it will have circles only.
5. Which of the following is an advantage of conic lofting?
a) Availability of diverse curves
b) Availability of simple drag only
c) Availability of simple lift drag
d) Availability of lift and drag only
Explanation: Conic lofting is done by using conic curves. A conic has number of different curves in family such as circle, ellipse etc. We can generate all such shapes via conic lofting. Hence, it is one of the advantages of it that it has availability of diverse curves
6. Conic is represented by _____
a) AX2 + BY2 + CXY + DX + EY + F = 0
b) AX2 + BY2 + CXY + DX + EY = 0
c) AX2 + BY2 + CXY + EY + F = 0
d) AX2 + BY2 + CXY + DX = 0
Explanation: A conic is a 2nd degree curve. Conic in simple mathematical language is defined by using AX2 + BY2 + CXY + DX + EY + F = 0. Constants are based on our requirements. WE can produce different cross-section shape such as circle, parabola etc. by using conic.
7. The first step of conic construction is __________
a) selecting desired end points at desired tangent angle
b) selecting a circle to proceed
c) selecting ellipse always
d) selecting parabola always
Explanation: Conic lofting method is a step by step method to generate conic of desired cross-section. In general, first step of any conic development is to fixe two end points of the shape. And based on this endpoint we will fix the tangent point as per our requirement
8. The purpose of the longitudinal control lines is __________
a) to connect end points, shoulder points and tangent point of different conic curves
b) to connect tangent points at half distance only of same conic curve
c) only to produce control of lifting lines of same curve
d) to change lifting line slope
Explanation: Longitudinal control lines are used to develop smoothly – lofted fuselage. Longitudinal control lines will connect end points of different conic curves. It is also used to connect different shoulder points and tangent points to respective shoulder points and tangent points of different conic curves.
9. What do you mean by longitudinal control lines?
a) Smooth lines which controls overall shape of the conic cross-section
b) Lines which expands to vertical direction only
c) Lines which go in horizontal direction only
d) Line which can be expanded only in lateral direction
Explanation: Longitudinal control lines are smooth lines through which conic curves are connected. Since, it connects all different conics, it will control the overall shape of the body itself during lofting.
10. Define control station.
a) Original cross-section used for longitudinal control lines
b) Auxiliary lines
c) Conic shape with circle only
d) Elliptic contour only
Explanation: Control stations are original cross section which are used to develop longitudinal lines. Control stations are also known as control cross- section. Control stations can be any type of conic curve. It can be circular, elliptic or any c/s as per our requirement.