AMNT 240 – Exam – Modules 4-6

Gasoline has a nominal weight of 6 pounds per gallon. So, 200 gallons of gasoline will weigh 1,200 pounds. The ratio of a load of 1,200-pound load to one of 1,680 pounds is the ratio of: 1,200 ÷ 1,680 = 0.7142. The ratio 5:7 is 0.7142. The ratio of 2:3 is 0.6667. The ratio of 5:42 is 0.1190.

Locations for fuselage frames in aircraft drawings are identified by station numbers.

An electrical wiring diagram shows the wire size required for a particular installation.

1. Follow the diagonal line for 20 amperes down until it intersects the 12-gage vertical line. 2. Draw a line horizontally to the left from this point of intersection. This line meets the 1-volt drop column at the 26.5-foot mark. 3. This point of intersection is above curve 1 showing that the wire can carry this load continuously without producing too much heat. 4. A 12-gage wire can carry 20 amperes continuously for 26.5 feet without overheating the wire and without producing a voltage drop of more than one volt.

Large drawings used for manufacturing aircraft are zoned to make it easy to locate parts, sections, and views on large drawings. Zone identifiers are placed every foot along the edge of the drawing. The identifiers along the bottom of the drawing are numbers and those up the side of the drawing are letters.

The volume of a rectangular solid figure (such as this fuel tank) is found by multiplying its length, width, and depth together. V = L x W x D = 37.5 x 14 x 8.25 = 4,331.25 cubic inches

The square root of 124.9924 is 11.18. 111.8 x 10^3 = 111,800 .1118 x 10^-2 = 0.001118 1,118 x 10^-2 = 11.18

The primary flight controls on a helicopter are the collective and cyclic control levers and anti-torque pedals. When the collective pitch control lever is raised, the blade angle of all the rotor blades increases uniformly and they create the lift that allows the helicopter to take off vertically. The cyclic pitch control lever, like the yoke of an airplane, can be pulled back or pushed forward (for backward or forward motion), and can be moved left and right (to bank left or right).

The temperature to which a body of air must be lowered before the water vapor in the air condenses out as visible, liquid water is called the dew point of the air.

The area of a trapezoid is found by multiplying its altitude (5 feet in this problem) by the average length of the two bases (the average of 9 feet and 12 feet is 10.5 feet). The area of this trapezoid is 5 x 10.5 = 52.5 square feet.

1. First, work the part of the problem inside the parenthesis: (32 x 3/8) = 12 2. Now divide 12 by 1/6. To divide by a fraction, invert the divisor (1/6) and multiply. 12 ÷ 1/6 = 12 x 6 = 72.

View 3 shows the aileron balance weight as seen from the direction shown by the arrow. This view shows the outline of the weight and the outline of the hole. Both of these are drawn as solid lines. The two bolt holes are shown as light, dashed lines (hidden lines), and there are also two hidden lines that show the break lines where the radius begins for the tip of the weight.

The area of a trapezoid is found by multiplying its altitude (2 feet in this problem) by the average length of the two bases (the average of 4 feet and 6 feet is 5 feet). The area of this trapezoid is 10 square feet.

A percentage is a decimal fraction with 100 as its denominator. To convert 7/8 into a percentage, divide seven by eight and multiply this by 100. 7 ÷ 8 = 0.875 0.875 x 100 = 87.5 percent

By using finished marks a drawing identifies those surfaces that must be machine finished.

Centerlines are made up of alternate long and short dashes. They indicate the center of an object or part of an object. Where centerlines cross, the short dashes intersect symmetrically. In the case of very small circles, the centerlines may be shown unbroken.

If the exact specifications of a material are shown on the drawing, the easily drawn symbol for cast iron is used for the sectioning, and the material specification is listed in the bill of materials or indicated in a note.

Dihedral or the upward slant of the wing from the fuselage is used to increase the lateral stability. Lateral stability is roll stability and is stability about the longitudinal axis.

A schematic diagram shows the relative location of all of the parts in a system, but does not give the location of the parts in the aircraft. Schematic drawings are of great help when troubeshooting a system.

The square root of 100 is 10. The square root of 36 is 6. The square root of 16 is 4. 10 + 6 – 4 = 12

Allowances are the difference between the nominal dimension of a part and its upper or lower limit. Dimensions are the measurements used to describe the size of an object. It is the ideal or ‘perfect’ size of the part. Tolerances are the differences between the extreme allowable dimensions of a part.

The maximum diameter of the finished clevis is 7/8 (0.875) inch. To be sure that every part of this maximum diameter is machined, we would need to use a larger bar of material to make it. 55/64 inch = 0.859375 (this is too small) 1 inch (this is the correct choice) 7/8 inch = 0.875 (this is too small)

1. Begin this problem by clearing the parentheses. (-3 + 2) = -1 (-12 – 4) = -16 (-4 +6) = 2 2. Then perform the multiplication. -1 x -16 = 16 2 x 3 = 6 3. And finally the addition. 16 + 6 = 22

A byte is composed of a group of 8 bits and represents a complete piece of information in a binary system.

The cube of a number is found by multiplying the number by itself three times. 64^3 = 64 x 64 x 64 = 262,144

The drawings used in illustrated parts manuals are exploded-view drawings.

The speed of sound in the atmosphere varies with the ambient temperature of the atmosphere.

Divide the decimal fractional part of this mixed number by the decimal equivalent of 1/64. .21875 ÷ 0.015625 = 14 The common fraction equivalent to 1.21875 is 1-14/64. This is the same as 78/64 or 39/32.

The volume of a rectangular solid figure (such as this fuel tank) is found by multiplying its length, width, and depth together. All dimensions must be in the same units. 3/4 foot = 9 inches. V = L x W x D = 27.5 x 9 x 8.25 = 2,041.875 cubic inches Since there are 231 cubic inches in each gallon, we must divide the total volume of 2,041.875 by 231 to find the capacity of the tank in gallons. Capacity = 2041.875 ÷ 231 = 8.83 gallons This tank will hold 8.83 gallons of fuel.

A pictorial diagram is similar to a photograph. It shows an object as it appears to the eye, but is not satisfactory for showing complex forms and shapes.

If an engine develops 108 horsepower at 87 percent power, its 100 percent power is 108 ÷ 0.87 = 124.13 horsepower. Its horsepower at 65 percent power is found by multiplying 124.13 by 0.65, or 80.68 horsepower.

The pressure of a gas in an enclosed container varies inversely as the volume of the container, if the absolute temperature of the gas remains constant. Doubling the volume of the container will decrease the pressure of the enclosed gas to a value of one-half its original pressure.

To convert a common fraction into a decimal fraction, divide the numerator by the denominator. 77 ÷ 64 = 1.203125

If the airplane uses 60 gallons of gasoline while flying 750 miles, it is getting 750 ÷ 60 or 12.5 miles per gallon of fuel burned. At this rate of fuel consumption, it will require 2,500 ÷ 12.5 = 200 gallons of fuel to fly 2,500 miles

“Stall strips are small triangular spoilers, or wedges, attached to the leading edge in the root area of a wing that has a tendency to stall at the tip before the root. Stalls beginning at the tip cause a loss of aileron effectiveness, and therefore lateral control, when it is most needed.

The piston displacement of one cylinder of a reciprocating engine is found by multiplying the area of the piston head by the length of the stroke. The area of the piston is found by squaring the bore (3.5 inches in this problem) and multiplying this by the constant 0.7854 (one fourth of pi). When the area of 9.621 square inches is multiplied by the stroke of 4.5 inches, we find that the displacement of one cylinder is 43.295 cubic inches. This is a six-cylinder engine, so the total displacement is six times that of a single cylinder. The total displacement is 259.77 cubic inches. Area = (pi ÷ 4) x B^2 = 0.7854 x 3.5^2 = 9.621 square inches Stroke = 4.5 inches PD = Area x Stroke x No. cylinders = 9.621 x 4.5 x 6 = 259.77 cubic inches

An easy way to find the center of a circle on a sketch is to draw two non-parallel chord lines across the circle. Then, draw a perpendicular bisector of each of these chord lines. The bisector lines will cross at the center of the circle.

Newton’s first law explains that when an object is at rest, it tries to remain at rest. But when it is moving, it tries to keep moving in a straight line and will not speed up, slow down, or turn unless it is acted upon by an outside force. This tendency of the object to remain in its original condition of motion is called inertia.

1. Follow the 15-ampere diagonal line down until it intersects the horizontal line for 40 feet in the 28-volt column. 2. This intersection occurs between the vertical lines for 12-gage and 10-gage wire. 3. You would need a 10-gage wire (always use the larger of the two wires) to carry a 15-amp load for 40 feet and not have more than a 1-volt drop.

The two holes in this part have a finished diameter of 1/2 inch. They are made by first drilling them to a diameter of 31/64 inch and then reaming them to their final diameter of 1/2 inch. This information is found in note 1.

In making a sketch of a repair, the first thing to do is to block in the views. As you block in the views, you are able to organize the sketch so it will clearly show the most information.

In this problem, the cost of the magneto is equal to 100 percent. Since a 12 percent profit is specified, the selling price must be 112 percent. If the selling price (112%) is equal to $145.60, the cost (100%) can be found by dividing the selling price by 112% (by 1.12). $145.60 ÷ 1.12 = $130.00

More information is given with this problem than is needed; therefore, it can cause confusion. The only work asked for is the amount needed to move the hoist. The hoist is moved for a distance of 12 feet and a constant force of 70 pounds is needed to move it. The work done to move the hoist is 12 x 70 = 840 foot-pounds.

Work is the product of the amount of force applied to an object times the distance through which the force causes the object to move. As much force is needed to hold back an object when it is being lowered as it does to raise the object. If 120 pounds of force is needed to hold back a weight as it is lowered for 3 feet, 360 foot-pounds of work has been done.

1. Follow the 2,300-RPM vertical line upward until it intersects the propeller load horsepower curve. 2. From the point of intersection, project a line horizontally to the left to read the brake horsepower the engine develops at 2,300 RPM. This is 110 brake horsepower. 3. Follow the 2,300-RPM curve upward until it intersects the propeller load brake specific fuel consumption curve. 4. From the point of intersection, project a line horizontally to the right to read the specific fuel consumption for 2,300 RPM. This is 0.46 pound of fuel burned per hour for each horsepower developed. 5. The engine burns 50.6 pounds of fuel per hour when it is developing 110 brake horsepower. 6. A 30-minute reserve would require one-half of this, or 25.3 pounds.

The binary number system has only two digits: 0 and 1. To convert a decimal number to a binary number, the place values in the binary system are used to create a sum of numbers that equal the value of the decimal number being converted. Start with the largest binary place value and subtract from the decimal number. Continue this process until all of the binary digits are determined. 7 = 0111 in binary.

The force a hydraulic actuator can exert is determined by the area of the piston and the pressure of the fluid acting on the piston. The effective area on the retracting side of the piston is two square inches. 2 sq. in. x 3,000 psi = 6,000 pounds of force

The binary number 00001111 is converted bit by bit into decimal: 1000 = 8; 0100 = 4; 0010 = 2; and 0001 = 1; thus the entire binary number equals 8 + 4 + 2 + 1 = 15 in its decimal form.

Almost all objects are composed of one or some combination of the triangle, circle, cube, cylinder, cone, and sphere.

An easy way to tell the power of 10 to which a number has been raised is to count the number of places the decimal would have to be moved to leave a number between 1 and 10. In this problem, the decimal would have to be moved nine places to the left. 1,000,000,000 is 1 x 10^9