AVGM 111 Final Exam Review

The parts department's profit is 12 percent on a new part. How much does the part cost if the selling price is $145.60?

$130.00 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 1.12. $145.60 ÷ 1.12 = $130.00

In a balance computation of an aircraft from which an item located aft of the datum was removed, use

(-)weight X (+)arm = (-)moment. A moment is a force that causes rotation about a point, and in order to specify the direction of the rotation, signs (+) and (-) are assigned to the moment. In aircraft weight and balance, a positive moment is a moment that causes the aircraft nose to go up, and a negative moment is one that causes the nose to go down. Since a moment is the product of weight and the distance from the datum and both of these are signed values, we have four choices for the sign of the moment: 1. A positive weight (weight added) and a positive arm (arm behind the datum) give a positive moment. 2. A positive weight and a negative arm (arm ahead of the datum) give a negative moment. 3. A negative weight (weight removed) and a positive arm give a negative moment. 4. A negative weight and a negative arm give a positive moment.

An aircraft with an empty weight of 2,100 pounds and an empty weight CG +32.5 was altered as follows: 1- two 18-pound passenger seats located at +73 were removed; 2- structural modifications were made at +77 increasing weight by 17 pounds; 3- a seat and safety belt weighing 25 pounds were installed at +74.5; and 4- radio equipment weighing 35 pounds was installed at +95. What is the new empty weight CG?

+33.68. ITEM WEIGHT ARM MOMENT Aircraft 2,100 32.5 68,250 Seats (remove) 36(-) 73 2,628(-) Modification 17 77 1,309 Seat 25 74.5 1,862.5 Radio 35 95 3,325 TOTAL 2,141 33.68 72,118.5 The new empty weight is 2,141 pounds, and the CG is located at fuselage station 33.68.

If a 40-pound generator applies +1400 inch-pounds to a reference axis, the generator is located

+35 from the axis. The distance from the axis is found by dividing the moment by the weight. 1,400 ÷ 40 = 35 Since the moment is positive, the arm will also be positive. The generator is located +35 inches from the axis.

Solve the equation. [(4 x -3)+(-9 x 2)] ÷ 2 =

-15 In a problem of this type, work from the inside outward: 1. First solve the parts of the problem inside the parentheses. 4 x -3 = -12, -9 x 2 = -18 2. Now combine the two values just found. -12 + -18 = -30 3. Divide this answer by 2. -30 ÷ 2 = -15

(Refer to Figure 59.) Solve the equation.

-5.20 This problem can be rewritten as 125 ÷ -4, divided by -36 ÷ -6. 125 ÷ -4 = -31.25 -36 ÷ -6 = 6 -31.25 ÷ 6 = -5.208

Solve the equation. -6[-9(-8 + 4) - 2(7 + 3)] =

-96 1. Begin the problem by working the inside parentheses in the first term. (-8 + 4) = -4 2. Combine the factors in the first term. -9 x -4 = 36 3. Clear the parenthesis in the second term. (7 + 3) = 10 4. Multiply this value by 2. 10 x 2 = 20 5. Combine the two terms in the brackets. 36 - 20 = 16 6. Multiply this by -6. -6 x 16 = -96

A certain aircraft bolt has an overall length of 1-1/2 inches, with a shank length of 1-3/16 inches, and a threaded portion length of 5/8 inch. What is the grip length?

.5625 inch. The grip length of a bolt is the length of the unthreaded portion of the shank. If the shank is 1-3/16 (1.1875) inches long, and the threaded portion is 5/8 (0.625) inch, the grip length is 1.1875 - 0.625 = 0.5625 inch.

Two boxes which weigh 10 pounds and 5 pounds are placed in an airplane so that their distance aft from the CG are 4 feet and 2 feet respectively. How far forward of the CG should a third box, weighing 20 pounds, be placed so that the CG will not be changed?

2.5 feet In order to not change the CG of the aircraft, it is necessary that the moment of the 20-pound weight be the same but have the opposite sign as the combined moments of the 10-pound box and the 5-pound box. The moment of the 10-pound box is 40 pound/feet. The moment of the 5-pound box is 10 pound/feet. The total positive moment is 50 pound/feet, and this must be balanced by a 50-pound/foot negative moment. By dividing the required moment by the weight, we find that the 20-pound box will have to be placed 2.5 feet ahead of the CG.

An airplane flying a distance of 750 miles used 60 gallons of gasoline. How many gallons will it need to travel 2,500 miles?

200 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

An aircraft as loaded weighs 4,954 pounds at a CG of +30.5 inches. The CG range is +32.0 inches to +42.1 inches. Find the minimum weight of the ballast necessary to bring the CG within the CG range. The ballast arm is +162 inches.

57.16 pounds. The CG of this aircraft is out of allowable range by 1.5 inches. Its CG is at fuselage station 30.5 and the forward CG limit is at station 32.0. To find the amount of ballast needed to be attached at fuselage station 162, multiply the empty weight of the aircraft by the distance the CG is to be moved and divide this by the distance between the ballast location and the desired CG location. Ballast weight = (Empty weight x Distance out) ÷ Distance ballast to new CG = (4954 x 1.5) ÷ (162 - 32) = 57.16 pounds Attaching a 57.16-pound ballast at fuselage station 162 will move the empty weight CG to fuselage station 32.0.

What is the ratio of a gasoline fuel load of 200 gallons to one of 1,680 pounds?

5:7 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.

If a double-acting actuating cylinder in a 3,000 psi system has a piston with a surface area of three square inches on the extension side, and a rod with a cross-section area of one square inch attached to the piston on the other side, approximately how much force will the actuator be able to produce when retracting?

6,000 pounds. 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

Express 5/8 as a percent.

62.5% To convert 5/8 into a percentage, divide five by eight and multiply this by 100. 5 ÷ 8 = 0.625 0.625 x 100 = 62.5 percent

(Refer to Figure 57.) Determine the area of the triangle formed by points A, B, and C. A to B = 7.5 inches A to D = 16.8 inches

63 square inches. The area of a triangle is equal to one-half the product of its base and its altitude. In this problem, the base is the distance A to D, which is 16.8 inches (this is the same as the distance B to C). The altitude is the distance A to B, which is 7.5 inches. Area = (16.8 x 7.5) ÷ 2 = 126 ÷ 2 = 63 square inches

If the volume of a cylinder with the piston at bottom center is 84 cubic inches and the piston displacement is 70 cubic inches, then the compression ratio is

6:1 The volume of a cylinder with the piston at the top of its stroke is found by subtracting the piston displacement of the cylinder from the volume of the cylinder with the piston at the bottom of its stroke. Volume at top = Volume at bottom - displacement = 84 - 70 = 14 cubic inches The compression ratio of the cylinder is the ratio of the volume of the cylinder with the piston at the bottom of its stroke to the volume of the cylinder with the piston at the top of its stroke. C.R. = Volume at bottom ÷ volume at top = 84 ÷ 14 = 6 This engine has a compression ratio of 6:1.

What is the piston displacement of a master cylinder with a 1.5-inch diameter bore and a piston stroke of 4 inches?

7.0686 cubic inches. The piston displacement of a master cylinder is found by multiplying the area of the piston head by its stroke. The area of the piston is found by squaring its diameter (1.5 inch in this problem) and multiplying this by the constant 0.7854 (one-fourth of pi). When the area of 1.767 square inches is multiplied by the stroke of 4.0 inches, we find that the displacement of the master cylinder to be 7.0686 cubic inches. PD = 0.7854 x B^2 x S = 0.7854 x 1.5^2 x 4 = 7.0686 cubic inches

Solve the equation. (32 x 3/8) ÷ 1/6 =

72 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.

How many gallons of fuel will be contained in a rectangular-shaped tank which measures 2 feet in width, 3 feet in length, and 1 foot 8 inches in depth? (7.5 gal = 1 cu ft)

75 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 = 3 x 2 x (20 ÷ 12) = 10 cubic feet Since 1 cubic foot of tank space will hold 7.5 gallons, and there are 10 cubic feet of space in the tank, the tank will hold 10 times 7.5 gallons or 75 gallons of fuel.

If the fluid pressure is 800 PSI in a 1/2-inch line supplying an actuating cylinder with a piston area of 10 square inches, the force exerted on the piston will be

8,000 pounds The size of the line that supplies fluid to an actuating cylinder has nothing to do with the amount of force the piston in the cylinder can exert. When a pressure of 800 psi acts on a piston with an area of 10 square inches, a force of 800 x 10 = 8,000 pounds is produced.

A rectangular shaped fuel tank measures 27-1/2 inches in length, 3/4 foot in width, and 8-1/4 inches in depth. How many gallons will the tank contain? (231 cu in = 1 gal)

8.83 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.

An engine develops 108 horsepower at 87 percent power. What horsepower would be developed at 65 percent power?

81 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.

Solve the equation. 4 - 3[-6(2 + 3) + 4] =

82 1. Begin this problem by working the inside parentheses, and then work outward. (2 + 3) = 5 (-6 x 5) = -30 (-30 + 4) = -26 2. Next, the multiplication is done. 3 x -26 = -78 3. Now, perform the subtraction. 4 - (-78) = 82

An engine that weighs 350 pounds is removed from an aircraft by means of a mobile hoist. The engine is raised 3 feet above its attachment mount, and the entire assembly is then moved forward 12 feet. A constant force of 70 pounds is required to move the loaded hoist. What is the total work input required to move the hoist?

840 foot-pounds. 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.

Express 7/8 as a percent.

87.5 percent. 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

Which is the ratio of the water vapor actually present in the atmosphere to the amount that would be present if the air were saturated at the prevailing temperature and pressure?

Relative humidity. Relative humidity is the ratio of the amount of water vapor actually present in the atmosphere to the amount that would be present if the air were saturated at the prevailing temperature and pressure.

What tasks are completed prior to weighing an aircraft to determine its empty weight?

Remove all items except those on the aircraft equipment list; drain fuel and fill hydraulic reservoir. Part 23, which applies to most general aviation aircraft, defines empty weight of an aircraft. Empty weight includes fixed ballast, unusable fuel, full operating fluids including oil, hydraulic fluid and other fluids required for normal operation of airplane systems except potable water, lavatory precharge water, and water intended for injection in the engines. When preparing an airplane for weighing, remove all items except those on the equipment list, drain the fuel, and fill the hydraulic reservoir.

Which of the following can provide the empty weight of an aircraft if the aircraft's weight and balance records become lost, destroyed, or otherwise inaccurate? 1) Reweighing the aircraft. 2) The applicable Aircraft Specification or Type Certificate Data Sheet. 3) The applicable flight manual or pilot's operating handbook.

Reweighing the aircraft. If the aircraft weight and balance records are lost, destroyed, or otherwise inaccurate, the aircraft must be re-weighed. The Aircraft Specification Sheet, Type Certificate Data Sheet, flight manual, and pilot's operating handbook do not list the empty weight of the specific aircraft.

Which device(s) is/are used to obtain the greatest accuracy of aircraft leveling?

Spirit level. The leveling means for determining weight and balance is specified by the aircraft manufacturer and is listed in the Type Certificate Data Sheets. Proper level may be determined with spirit levels placed across leveling lugs or along the door sill.

Which statement concerning heat and/or temperature is true? 1) There is an inverse relationship between temperature and heat. 2) Temperature is a measure of the kinetic energy of the molecules of any substance. 3) Temperature is a measure of the potential energy of the molecules of any substance.

Temperature is a measure of the kinetic energy of the molecules of any substance. Heat is a form of energy, and temperature is a measure of the intensity of the kinetic energy of the molecules in a substance. Heat energy, in the form of latent heat, can be added to an object or taken from it without changing its temperature. But, the temperature of an object changes directly with the amount of sensible heat put into it or taken from it.

What is absolute humidity?

The actual amount of the water vapor in a mixture of air and water. Absolute humidity is the actual amount of water in a volume of air. It is measured in such units as grams per cubic meter.

What determines whether the value of a moment is preceded by a plus (+) or a minus (-) sign in aircraft weight and balance?

The location of the weight relative to the datum and if it is being removed or added. A moment is a force that causes rotation about a point, and in order to specify the direction of the rotation, (+) and (-) signs are assigned to the moment. A positive moment is one that causes the aircraft nose to go up, and a negative moment is one that causes the nose to go down. Since a moment is the product of weight and the distance from the datum, and both of these are signed values, we have four choices for the sign of the moment: 1. A positive weight (weight added) and a positive arm (arm behind the datum) give a positive moment. 2. A positive weight and a negative arm (arm ahead of the datum) give a negative moment. 3. A negative weight (weight removed) and a positive arm give a negative moment. 4. A negative weight and a negative arm gives a positive moment.

The useful load of an aircraft consists of the

crew, usable fuel, passengers, and cargo The useful load of an aircraft is the difference between its empty weight and the maximum allowable gross weight. It does not include any of the fixed or required equipment as these are part of the empty weight.

The temperature to which humid air must be cooled at constant pressure to become saturated is called

dewpoint. 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 boiling point of a given liquid varies

directly with pressure. The boiling point of a liquid varies directly with the pressure above the liquid. The greater the pressure, the higher the boiling point.

The maximum weight of an aircraft is the

empty weight plus useful load The useful load of an aircraft is found by subtracting the empty weight of the aircraft from the maximum weight. Therefore, the maximum weight is the sum of the empty weight and the useful load.

The purpose of stall strips on airplane wings is to

ensure that the wing root areas stall first. Stall strips are small triangular spoilers, or wedges, attached to the leading edge at 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. At high angles of attack, stall strips disrupt the airflow over the wing root and force it to stall before the portion of the wing ahead of the aileron.

If it is necessary to weigh an aircraft with full fuel tanks, all fuel weight must be subtracted from the scale reading(s)

except unusable fuel. The empty weight of an aircraft includes the weight of the unusable fuel. The weight and location of the unusable fuel is found in Note 1 in the section of the Type Certificate Data Sheets, 'Data pertinent to All Models.'

All other things being equal, if an item of useful load located aft of an aircraft's CG is removed, the aircraft's CG change will be

forward in proportion to the weight of the item and its location in the aircraft. An item located aft of an aircraft's CG has a positive arm, and when it is removed, it has a negative weight. A positive arm and a negative weight produce a negative moment. (+ arm x - weight = - moment). A negative moment moves the CG forward by an amount that is proportional to the weight of the item and its location in the aircraft.

To obtain useful weight data for purposes of determining the CG, it is necessary that an aircraft be weighed

in a level flight attitude. When an aircraft is being weighed, it must be placed in a level-flight attitude. When the aircraft is in its level-flight attitude, the centers of gravity of all of the items are in their correct locations relative to the datum.

The maximum weight as used in weight and balance control of a given aircraft can normally be found

in the Aircraft Specification or Type Certificate Data Sheet. Type Certificate Data Sheets or Aircraft Specifications include the maximum certificated gross weight of an aircraft.

The purpose of aircraft wing dihedral is to

increase lateral stability. 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.

The desired effect of using winglets on an aircraft's wingtips is to

increase the lift to drag ratio. Winglets, small upturned vertical surfaces mounted on the wing tips, reduce drag by reducing the spanwise flow of air, therefore reducing vortices. The desired effect of using winglets on an aircraft's wingtips is to increase the lift to drag (L/D) ratio of the wing.

Maximum zero fuel weight is the

maximum permissible weight of a loaded aircraft (passengers, crew, and cargo) without fuel. The zero fuel weight of an aircraft is the maximum allowable weight of the loaded aircraft without fuel. The weight of the cargo, passengers, and crew are included in the zero fuel weight.

The CG range in single-rotor helicopters is

more restricted than for airplanes Most helicopters have a much more restricted CG range than do airplanes. In some cases, this range is less than three inches.

1- Private aircraft are required by regulations to be weighed periodically. 2- Private aircraft are required to be weighed after making any alteration. Regarding the above statements,

neither 1 nor 2 is true. Statement 1 is not true. No Federal Aviation Regulation requires that private aircraft be weighed periodically. Statement 2 is not true. When a private aircraft is altered, the weight and balance records must be updated to show any change that has been made in the weight or in the empty weight CG location. These changes are normally found mathematically rather than by actually weighing the aircraft.

If both the volume and the absolute temperature of a confined gas are doubled, the pressure will

not change. The pressure exerted by a confined gas is directly proportional to its absolute temperature. If the absolute temperature is doubled, the pressure will also double. The pressure exerted by a confined gas is inversely proportional to its volume. If its volume is doubled, the pressure will decrease to a value that is one half of the original. If both the volume and the absolute temperature of a confined gas are doubled, the two changes will cancel each other, so the pressure of the gas will not change.

In the process of weighing an airplane toward obtaining the CG, the arms from the weighing points always extend

parallel to the centerline of the airplane. An arm, used in determining the CG of an airplane, is the horizontal distance from the datum to the center of gravity of the item. An arm is always measured parallel to the centerline of the airplane.

Select the decimal which is most nearly equal to 77/64.

1.2031 To convert a common fraction into a decimal fraction, divide the numerator by the denominator. 77 ÷ 64 = 1.203125

Select the fractional equivalent for a 0.0625 inch thick sheet of aluminum.

1/16 In order to change this decimal fraction into a common fraction, divide the number by the decimal equivalent of 1/64 (0.015625). 0.0625 ÷ 0.015625 = 4/64 This is the same as 1/16 inch.

Select the fraction which is equal to 0.0250.

1/40 1/40 is equal to 0.025. 1/4 is equal to 0.25. 1/400 is equal to 0.0025.

Solve the equation. 1/2 (-30 + 34) 5

10 First, solve the part of the problem inside the parenthesis, then multiply by 1/2 (divide by 2) and finally multiply by five. (-30 + 34) = 4 4 ÷ 2 = 2 2 x 5 = 10

(Refer to Figure 60.) Solve the equation.

11.9 1. Begin this problem by clearing the parentheses. (-5 + 23) = 18 (3^-3) = 0.037 The square root of 64 = 8 2. Perform the multiplication in the numerator. 18 x -2 = -36 0.037 x 8 = 0.296 3. Perform the addition in the numerator. -36 + 0.296 = -35.704 4. Perform the division in the denominator. -27 ÷ 9 = -3 5. Divide the numerator by the denominator. -35.704 ÷ -3 = 11.90

(Refer to Figure 58.) Solve the equation.

14.002 1. First, solve the parts of the problem inside parentheses: (-35 + 25) = (-10) 2. Combine the factors (the parts) of the first term (the part of the problem to the left of the plus sign). (-10) x (-7) = 70 3. Clear the parenthesis on the right of the plus sign by raising 16 to its ^-2 power. 16^-2 = 1/16^2 = 1/256 = 0.003906 4. Multiply the two factors of the second term. (3.1416) x (0.003906) = 0.01227 5. Add the two terms above the line. 70 + 0.0122 = 70.0122 6. Divide this by the square root of 25, which is 5. 70.0122 ÷ 5 = 14.002

What is the speed of a spur gear with 42 teeth driven by a pinion gear with 14 teeth turning 420 RPM?

140 RPM The speed ratio is the reciprocal of gear ratio. The spur gear with 42 teeth is driven by a pinion gear with 14 teeth. This is a gear ratio of 3:1. The spur gear will turn at 1/3 the speed of the pinion gear. If the pinion gear turns at a speed of 420 RPM, the spur gear will turn at a speed of 420 ÷ 3 = 140 RPM.

(Refer to Figure 61.) The amount of force applied to rope A to lift the weight is

15 pounds. This block and tackle supports the weight with four ropes, and this gives it a mechanical advantage of four. To lift a 60-pound weight, a force of 15 pounds must be exerted on rope A. Rope A will have to be pulled four times the distance the weight is lifted.

As weighed, the total empty weight of an aircraft is 5,862 pounds with a moment of 885,957. However, when the aircraft was weighed, 20 pounds of potable water were on board at +84, and 23 pounds of hydraulic fluid were in a tank located at +101. What is the empty weight CG of the aircraft?

151.365 When weighing an aircraft to find its empty weight, a full reservoir of hydraulic fluid is included, but the potable water is not part of the required equipment. ITEM WEIGHT ARM MOMENT Aircraft 5,862 151.13 885,957 Potable water 20(-) 84 1,680(-) TOTAL 5,842 151.365 884,277 When the potable water is computed out of the empty weight, we find the new empty weight to be 5,842 pounds and the new empty weight CG is located at fuselage station 151.365.

What is the speed ratio of an input gear with 36 teeth meshed to a gear with 20 teeth?

1:1.8 The speed ratio is the reciprocal of the gear ratio. The large gear has 36 teeth and the small gear has 20 teeth. This is a gear ratio of 1.8:1, or a speed ratio of 1:1.8.

A four-cylinder aircraft engine has a cylinder bore of 3.78 inches and is 8.5 inches deep. With the piston on bottom center, the top of the piston measures 4.0 inches from the bottom of the cylinder. What is the approximate piston displacement of this engine?

200 cubic inches. 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 (3.78 inches in this problem) and multiplying this by the constant 0.7854 (one-fourth of pi). When the area of 11.22 square inches is multiplied by the stroke of 4.5 inches (the depth of the cylinder minus the distance from the top of the piston at BDC to the bottom of the cylinder), we find that the displacement of one cylinder is 50.49 cubic inches. This is a four-cylinder engine, so the total displacement is four times that of a single cylinder. The total displacement is 201.96 cubic inches. Area = (pi ÷ 4) x B^2 = 0.7854 x 3.78^2 = 11.22 square inches Stroke = 8.5 - 4 = 4.5 inches PD = Area x Stroke x Number of cylinders = 11.22 x 4.5 x 4 = 201.96 cubic inches

Solve the equation. (-3 + 2)(-12 - 4) + (-4 + 6) x 3

22 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 six-cylinder engine with a bore of 3.5 inches, a cylinder height of 7 inches and a stroke of 4.5 inches will have a total piston displacement of

259.77 cubic inches. 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 Number of cylinders = 9.621 x 4.5 x 6 = 259.77 cubic inches

Solve the equation. (64 x 3/8) ÷ 3/4 =

32 First work the part of the problem inside the parenthesis, and then do the division. 64 x 3/8 = 24 24 ÷ 3/4 = 32

Which will weigh the least? 1) 98 parts of dry air and 2 parts of water vapor. 2) 35 parts of dry air and 65 parts of water vapor. 3) 50 parts of dry air and 50 parts of water vapor.

35 parts of dry air and 65 parts of water vapor. Water vapor is only about 5/8 as heavy as an equal volume of dry air. The more water vapor in the air, the less the air weighs. In choice A there is 2 percent water vapor. In choice B there is 65 percent water vapor. In choice C there is 50 percent water vapor.

(Refer to the Figure 66.) N/A Solve the equation.

36,002 -4 + 6 + 10^3(square root 1296) simplifies to 2 + 1,000(36), which equals 36,002.

How much work input is required to lower (not drop) a 120-pound weight from the top of a 3-foot table to the floor?

360 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.

1-21875 is equal to

39/32 Divide the decimal fractional part of this mixed number by the decimal equivalent of 1/64. 0.21875 ÷ 0.015625 = 14 The common fraction equivalent to 1.21875 is 1-14/64. This is the same as 78/64 or 39/32.

A rectangular-shaped fuel tank measures 37-1/2 inches in length, 14 inches in width, and 8-1/4 inches in depth. How many cubic inches are within the tank?

4,331.25 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

What force must be applied to roll a 120-pound barrel up an inclined plane 9 feet long to a height of 3 feet (disregard friction)? L ÷ I = R ÷ E L = Length of ramp, measured along the slope. I = Height of ramp. R = Weight of object to be raised or lowered. E = Force required to raise or lower object.

40 pounds. This is a simple mechanical advantage problem. We roll the barrel three times as far as we lift it, so the force we must exert to roll the barrel up the inclined plane is only one third of the weight of the barrel. We must exert a force of 40 pounds to roll a 120-pound barrel up the 9-foot inclined plane to lift it 3 feet.

A pinion gear with 14 teeth is driving a spur gear with 42 teeth at 140 RPM. Determine the speed of the pinion gear.

420 RPM. The speed ratio is the reciprocal of the gear ratio. The spur gear with 42 teeth is driven by a pinion gear of 14 teeth. This is a gear ratio of 3:1. The spur gear will turn at 1/3 the speed of the pinion gear. If the spur gear turns at a speed of 140 RPM, the pinion gear will have to turn at a speed of 420 RPM.

Which condition is the actual amount of water vapor in a mixture of air and water?

Absolute humidity. Absolute humidity is the actual amount of water in a volume of air, and it is measured in such units as grams per cubic meter.

The speed of sound in the atmosphere is most affected by variations in which of the following? 1) Sound frequency. 2) Ambient temperature. 3) Barometric pressure.

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

Which of the following is NOT considered a method of heat transfer? 1) Convection. 2) Conduction. 3) Diffusion.

Diffusion Heat can be transferred from a body having a high level of heat energy to a body having a lower level of heat energy by three methods: conduction (actual physical contact), convection (transfer through vertical currents), and radiation (transfer by electromagnetic waves). Diffusion is not a method of heat transfer.

What type of measurement is used to designate the arm in weight and balance computation?

Distance The arm used in weight and balance computation is the distance, in inches, between the center of gravity of an object and the aircraft datum.

In physics, which of the following factors are necessary to determine power? 1) Force exerted, distance moved, and work. 2) Distance moved and time required. 3) Force exerted, distance moved, and time required.

Force exerted, distance moved, and time required. Power is the time rate of doing work. In order to determine the amount of work done, we must know the amount of force used and the distance through which this force acted. Force times distance is equal to work. The amount of power needed is found by dividing the amount of work done by the time used in doing the work. To find the amount of power needed to do a job, we must know the force, the distance, and the time.

Which atmospheric conditions will cause the true landing speed of an aircraft to be the greatest?

High temperature with high humidity. The true landing speed of an aircraft is determined by the density of the air. The amount of aerodynamic lift produced by the wing of an airplane or the rotor of a helicopter is determined by several things. Among these are the shape of the airfoil, the speed of the airfoil through the air, and the density of the air. The denser the air, the lower the speed that will produce the same amount of lift. Density of the air depends upon both its temperature and its humidity. The hotter the air, the less dense. The more water vapor in the air (the higher its humidity), the less dense the air. An airplane will have to fly the fastest to produce the required lift under conditions of high temperature and high humidity.

Most modern aircraft are designed so that if all seats are occupied, full baggage weight is carried, and all fuel tanks are full, what will be the weight condition of the aircraft?

It will be in excess of maximum takeoff weight. Most modern aircraft are designed so that if all seats are occupied, full baggage weight is carried, and all fuel tanks are full, the aircraft will be grossly overloaded. It will be in excess of maximum takeoff weight.

Which of the following have an effect on aircraft CG results when conducting a weight and balance check? 1) Leaving the parking brake on. 2)Leaving the parking brake off. 3)Leaving the downlocks installed.

Leaving the downlocks installed. All of the required equipment must be properly installed, and there should be no equipment installed that is not included in the equipment list.

In the theory of weight and balance, what is the name of the distance from the fulcrum to an object?

Lever arm. In the theory of weight and balance, the distance of any object from the fulcrum is called the lever arm.

Which of the following is Newton's first law of motion, generally termed the law of inertia?

Objects at rest tend to remain at rest and objects in motion tend to remain in motion at the same speed and in the same direction, unless acted on by an external force. 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.

Which of the following may cause erroneous scale readings? 1) Wheel chocks in place. 2) Parking brakes set. 3) Parking brakes not set.

Parking brakes set. When positioning an aircraft on platform type scales for weighing, the parking brakes must be released so there will be no side load applied to the scale platform. Any side load will cause an erroneous scale reading.

What FAA-approved document gives the leveling means to be used when weighing an aircraft?

Type Certificate Data Sheet. The FAA-approved document that gives the leveling means to be used when weighing a specific aircraft is the Type Certificate Data Sheet for that aircraft.

Under which conditions will the rate of flow of a liquid through a metering orifice (or jet) be the greatest (all other factors being equal)? 1) Unmetered pressure, 18 psi; metered pressure, 17.5 psi; atmospheric pressure, 14.5 psi. 2) Unmetered pressure, 23 psi; metered pressure, 12 psi; atmospheric pressure, 14.3 psi. 3) Unmetered pressure, 17 psi; metered pressure, 5 psi; atmospheric pressure, 14.7 psi.

Unmetered pressure, 17 psi; metered pressure, 5 psi; atmospheric pressure, 14.7 psi. In answering this question, we must recognize that the atmospheric pressure acts equally on both sides of the metering jet and therefore does not enter into the problem. The metering jet with the greatest pressure differential across it will have the greatest rate of flow through it. Jet A has a pressure differential of 0.5 psi differential. Jet B has a pressure differential of 11 psi differential. Jet C has a pressure differential of 12 psi differential.

What should be clearly indicated on the aircraft weighing form?

Weighing points. Since the weight and balance computations are based on the scale weights of an aircraft, the weighing form used with a specific aircraft should specify not only the leveling means, but also the location of the weighing points.

Which statement is true regarding helicopter weight and balance? 1) Lateral axis CG control is not a factor in maintaining helicopter weight and balance. 2) The moment of tail-mounted components is subject to constant change. 3)Weight and balance procedures for airplanes also apply to helicopters.

Weight and balance procedures for airplanes also apply to helicopters. When computing the weight and balance of an aircraft, it makes no difference whether the aircraft has a fixed wing or a rotary wing. The procedures are the same, but the actual effect of weight and balance is more critical for a helicopter than for a fixed-wing aircraft.

A wing with a very high aspect ratio (in comparison with a low aspect ratio wing) will have

a low stall speed. Wings with a high aspect ratio have low drag at high angles of attack, low stalling speed, and good control at low airspeeds. Sailplanes have very high aspect ratios and fly slowly.

When determining the empty weight of an aircraft, certificated under current airworthiness standards (14 CFR Part 23), the oil contained in the supply tank is considered

a part of the empty weight. The empty weight of an aircraft certificated under Part 23 includes a full supply tank of engine oil.

If the reference datum line is placed at the nose of an airplane rather than at the firewall or some other location aft of the nose,

all measurement arms will be in positive numbers. The reference datum used for weight and balance purposes can be located anywhere the aircraft manufacturer chooses. Current practice is to locate it on or near the nose or out ahead of the aircraft. The reason for this is that all of the arms will be positive (they will all be behind the datum). If all of the arms are positive, the moment of all added weight will be positive, and the moment of all removed weight will be negative. This will simplify weight and balance computations and will give less chance for error.

If all, or a significant part of a stall strip is missing on an airplane wing, a likely result will be

asymmetrical lateral control at or near stall angles of attack. "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.

When dealing with weight and balance of an aircraft, the maximum weight is interpreted to mean the maximum

authorized weight of the aircraft and its contents. Maximum weight, when considering the weight and balance of an aircraft, is the maximum certificated weight of the aircraft as specified on the Type Certificate Data Sheet or in the Aircraft Specification.

If the volume of a confined gas is doubled (without the addition of more gas), the pressure will (assume the temperature remains constant)

be reduced to one-half its original value. 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.

The speed of sound in the atmosphere

changes with a change in temperature The speed of sound in the atmosphere varies with the temperature of the atmosphere.

An airplane wing is designed to produce lift resulting from

positive air pressure below the wing's surface and negative air pressure above the wing's surface along with the downward deflection of air. Aerodynamic lift is produced on an airfoil by the pressure difference across the airfoil along with the downward deflection of air. The pressure below the wing surface is greater than that above the wing. The pressure below the wing may be considered positive and that above the wing negative.

Improper loading of a helicopter which results in exceeding either the fore or aft CG limits is hazardous due to the

reduction or loss of effective cyclic pitch control. If a helicopter is loaded in such a way that its CG is either too far forward or too far aft, flight will be hazardous. The cyclic pitch control will likely not be effective enough to control the helicopter against its out-of-balance condition.

If the temperature of a confined liquid is held constant and its pressure is tripled, the volume will

remain the same. A liquid is considered to be a noncompressible fluid. Its volume changes with a change in its temperature but it remains relatively constant as its pressure changes. If the pressure on a confined liquid is tripled, the volume of the liquid will remain virtually the same.

The major source of weight change for most aircraft as they age is caused by

repairs and alterations. Changes of fixed equipment may have a major effect upon the weight of an aircraft. Many aircraft are overloaded by the installation of extra radios or instruments.

The empty weight of an airplane is determined by

subtracting the tare weight from the scale reading and adding the weight of each weighing point When an aircraft is to be weighed, it is placed on the scales and chocked to prevent its rolling. The weight of the chocks is called tare weight. The empty weight of the aircraft is found by subtracting the tare weight from the scale readings, to get the net weight. The net weight from each weighing point is added to get the total net weight which is the total empty weight of the aircraft.

When computing weight and balance, an airplane is considered to be in balance when

the average moment arm of the loaded airplane falls within its CG range. An airplane is considered to be in balance when the average moment arm of the loaded aircraft falls within its CG range.

The useful load of an aircraft is the difference between

the maximum takeoff weight and basic empty weight. The useful load of an aircraft is the difference between the maximum takeoff weight and the basic empty weight of the aircraft.

The amount of fuel used for computing empty weight and corresponding CG is

unusable fuel. The amount of fuel to be in the aircraft when it is weighed for purposes of finding its empty weight is only the unusable fuel. If the aircraft is weighed with full fuel tanks, the weight of the fuel must be subtracted from the weight found by the scales. The weight of the unusable fuel and its CG can be found in the Type Certificate Data Sheet for the aircraft.

Aspect ratio of a wing is defined as the ratio of the

wingspan to the mean chord. The aspect ratio of a wing is the ratio of the wing span to the mean, or average, chord. For a nonrectangular wing, aspect ratio is found by dividing the square of the wing span by the wing area.