Aircraft Math

Mathematics

• A rectangular tank measuring 2 feet in width, 3 feet in length, and 1 foot 8 inches in depth will contain 75 gallons of fuel.
• The square root of 4 raised to the 5th power is 32.
• For a 0.0625-inch-thick sheet of aluminum, the fractional equivalent is 1/16.
• 3.47x 104 = 34, 700 and 2(410) 2,097,152 are both using scientific notation.
• The decimal that is most nearly equal to a bend radius of 31/64 is 0.4844.
• The speed ratio of an input gear with 36 teeth meshed to a gear with 20 teeth is 9:5.
• 7 raised to the third power added to the square root of 39 equals 349.24.
• For a blueprint showing a hole of 0.171787 to be drilled, the fraction size drill bit that is most nearly equal is 11/64.
• 7/8 expressed as a percent is 87.5 percent.
• 1.63x10 to the fourth power is equal to 16,300.
• A four cylinder aircraft engine with a cylinder bore of 3.78 inches and is 8.5 inches deep, with the piston on bottom center and the top of the piston measures 4.0 inches from the bottom of the cylinder - the approximate piston displacement of this engine is 200 cubic inches.
• The total piston displacement of a specific engine is the volume displaced by all the pistons during one revolution of the crankshaft.
• For a triangle with a base of 4 inches and a height of 6 inches, the area is 12 square inches.
• If the maximum life for a certain part is 1100 hours and 15 of these parts were removed from different aircraft with an average life of 835.3 hours, then 75.9 percent of the maximum part life has been achieved.
• 10 raised to the negative sixth power is 0.000001.
• The ratio of 10 feet to 30 inches is 4:1.
• Solving the equation -6[-9(-8+4)-2(7+3)] = results in -332.
• Solving the equation 31+2/43/=(17)2 results in .0297.
• Solving the equation 4-3[-6(2+3) + 4] = results in 82.
• To fabricate a cylinder 20 inches long and 8 inches in diameter, the required sheet metal size is 20 inches x25-5/32 inches.
• 1.21875 is equal to 39/32.
• An engine develops 108 horse power at 87 percent power, then 70 horsepower would be developed at 65 percent power.
• The fraction which is equal to 0.0250 is 1/40.
• The square root of 1824 is 42.708x10 to the negative second power.
• The square root of 1746 is 41.7852.
• If the parts department's profit is 12 percent on a new part and the selling price is $145.60, then the part costs $130.00.
• The square root of 3,722.1835 is 61.0097.
• An aircraft bolt has an overall length of 1-1/2 inches, a shank length of 1-3/16 inches, and a threaded length of 5/8 inch - the grip length is .5625 inch.
• The cube of 64 is 262,144.
• The surface area of a cube where a side (edge) measures 7.25 inches is 315.375 sq. in.
• A rectangular shaped fuel tank measures 27-1/2 inches in length, 3/4 foot in width, and 8-1/4 inches in depth - measures 7.366.
• The equation (√100 + √36 - √16= equals 12.
• Sixty-five engines are 81 percent of 80 engines.
• The equation (-35+25)(-7) + (π)(16)-2/√25 equals 68.037.
• The binary number 1111 converts to 15 in decimal form.
• The ratio of a gasoline fuel load of 200 gallons to one of 1680 pounds is 5:42.
• Byte is defined as a group of bits representing a complete piece of information.
• The equation (64x3/8) 3/4 = euqals 18.
• 10 to the ninth power is equal to 1,000,000,000.
• When the volume of a cylinder with the piston at the bottom center is 84 cubic inches and the piston displacement is 70 cubic inches, the compression ratio is 6:1.
• If an airplane flying travels a distance of 750 miles using 60 gallons of gasoline, then 200 gallons are needed to travel 2,500 miles.
• If a master cylinder has a 1.5 inch diameter bore and a piston stroke of 4 inches, the piston displacement is 7.0686 cubic inches.
• The square root of 124.924 is 1118x10 to the negative second power.
• For a trapezoid with bases of 4 inches and 6 inches and a height of 3 inches, the area is 15 square inches.
• A rectangular-shaped fuel tank measuring 60 inches in length, 30 inches in width and 12 inches in depth has 12.5 cubic feet within the tank.
• A spur gear with 42 teeth driven by a pinion gear with 14 teeth turning at 420 RPM has a speed of 140 RPM.
• The alternative answer equal to 5.59 is (√31 + √43) + 172.
• The decimal which is most nearly equal to the diameter if the radius of a piece of round stock is 7/32 is 0.4375.
• An engine turning at 1,965 rpm at 65 percent power will have a maximum rpm of 3023.
• If a pinion gear with 14 teeth is driving a spur gear with 42 teeth at 140 RPM, the speed of the pinion gear is 420 RPM.
• For a triangle with a base of 7.5 inches and a height of 16.8 inches, the area is 63 square inches.
• The current drawn from the bus for a 30-volt, 1/2 horsepower motor with 85 percent efficiency is 14.6 amperes.
• The square root of (-1776)/(-2)-632 is 16.
• The force exerted on the piston in a hydraulic cylinder if the area of piston is 1.2 square inches and the fluid pressure is 850 PSI is 1,020 pounds.
• A 6 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 equation -4√125/-6-3√5 equals -5.20.
• The squareroot of 16 raised to the fourth power is 256.
• The number 3.47x 10 to the negative fourth power is 0.000347.
• Solving the equation (−5+23)(-2) + (3-3) (√64)/-27=9 equals 11.7.
• The decimal which is most nearly equal to 77/64 is 1.2031.
• The solution for (32x 3/8) 1/6 = is 2.
• The solution of 1/2 (-30+34)5 is 10.
• The solution for [4 x-3) +(-9x2)] ÷2= is -15.
• A rectangular shaped fuel tank measures 37-1/2 inches in length, 14 inches in width and 8-1/4 inches in depth contains 4331.25 cubic inches.
• For a trapezoid with bases of 5’ and 12’and a height of 9’, the area is 76.5 square feet.
• 5/8 expressed as as a percent is 62.5 percent.
• An engine of 98 horse power maximum running at 75 percent power is developing horsepower of 73.50.
• The solution of (-3+2) (-12-4)+(-4+6) x3 equals 22.
• The container size will be equal in volume to 60 gallons on fuel - 8.0 cubic feet.
• The solution for -4+6+103 (√1296) = is 36002.

Materials and Processes

• In general, bolt grip lengths should equal the material thickness is a correct statement regarding aircraft bolts.
• For x-ray exposure, processing of the film, material thickness and density, and exposure distance and angle are all essential knowledge.
• To measure crankpin and main bearing journals for out-of-round wear, a micrometer caliper is used.
• On a fillet weld, the penetration requirement includes 25-50 percent of the base metal thickness.
• Slow cooling and low strength describes the annealing process of steel after it has been annealed.
• Piston pin out-of-round wear can be gauged with a micrometer caliper
• When conducting a dye or fluorescent penetrant inspection, the main determinant governing dwell time is the size and shape of the discontinuities being looked for.
• The residual magnetizing inspection method may be used with steels which have been heat treated for stressed applications
• In examining and evaluating a welded joint, a mechanic should be familiar with likely ambient exposure conditions and intended use of the part, the type of weld, and original part material composition.
• Circular magnetization of a part can be used to detect defects perpendicular to the long axis of the part
• (1) In nondestructive testing a discontinuity may be defined as an interruption in the normal physical structure or configuration of a part AND (2) A discontinuity may or may not affect the usefulness of a part are both correct statements.
• In performing a dye penetrant inspection, the developer acts as a blotter to produce a visible indication.
• If it is necessary to accurately measure the diameter of a hole approximately 1/4 inch in diameter, the mechanic should use a small-hole gauge and determine the size of the hole by taking a micrometer reading of the ball end of the gauge.
• The continuous method of magnetic particle inspection is used most often to inspect aircraft parts for invisible cracks and other defects.
• The two types of indicating mediums available for magnetic particle inspection include wet and dry process materials.
• The most common cause for dye penetrant inspection indications not being sharp and clear is that the part was not thoroughly washed before the developer was applied.
• Aluminum alloy designations which indicate that the metal has received no hardening or tempering is indicated by 3003-F
• Heat-treating operation introduces a high carbide or nitride content and the surface of the metal will be changed chemically is called case hardening.
• Unless otherwise specified, torque values for tightening aircraft nuts and bolts relate to clean, lightly oiled threads.
• Eddy current inspection requires little or no part preparation, is used to detect surface or near-surface defects in most metals, and may also be used to separate metals or alloys and their heat-treat conditions.
• The locking feature of the fiber-type locknut is obtained by the use of an unthreaded fiber locking insert.
• When the specific torque value for nuts is not given, the recommended torque value can be found at AC 43. 13-1B.
• Alclad is a metal consisting of pure aluminum surface layers on an aluminum alloy core.
• Unacceptable defects for metal lines include cracked flares, seams, dents in the heel of a bend less than 20% of the dimeter.
• Case hardening is a heat-treating process of metal and produces a hard, wear-resistant surface over a strong, tough core.
• Generally speaking, bolt grip lengths equal to the thickness of the material which is fastened together
• Annealing steel and aluminum alloys results in; decrease in internal stress and softening of metal
• A bolt labeled with an X inside a triangle on the head is classified as an NAS close tolerance bolt.
• When checking an item with the magnetic particle inspection method, circular and longitudinal magnetization should be used to Reveal all possible defects
• Unless otherwise specified or required, aircraft bolts should be installed so that the bolthead is Downward, or in a forward direction
• (1) An aircraft part may be demagnetized by subjecting it to a magnetizing force from alternating current that is gradually reduced in strength And (2) An aircraft part may be demagnetized by subjecting it to a magnetizing force from direct current that is alternately reversed in direction and gradually reduced in strength Both statements are correct.
• The percentage of carbon in the alloy in hundredths of a percent is indicated by the first digit in the 4130 steel number.
• The metals become cold worked, strain or work hardened occurs when a mechanical force is repeatedly applied to most metals at room temperature, such as rolling, hammering, or bending.
• Iron alloys may be inspected using the magnetic particle inspection method.
• Steel tempering after being hardened reduces its internal stresses and reduces its brittleness.
• Cracking adjacent to the weld is an indication that a part has cooled too quickly after being welded.
• By the use of an unthreaded fiber locking insert is how the locking feature of the fiber-type locknut is obtained
• Clad aluminum alloy cannot be heat treated repeatedly without harmful effects.
• .0001 represents the Vernier scale graduation of a micrometer.
• An outside micrometer is limited is an incorrect statement to measuring diameters
• Alloy steel bolts smaller than ¼ inch diameter should not be used in primary structure is a correct statement regarding aircraft bolts
• Stainless steel is generally used in the construction of aircraft engine firewalls
• To relieve internal stresses developed within the base metal is why consider a good practice to normalize a part after welding
• Aircraft bolts are usually manufactured with a Class 3 fit for the threads
• A fiber-type, self-locking nut must never be used on an aircraft if the bolt is Subject to rotation 99 percent commercially pure aluminum is identified by the aluminum code number 1100 Magnetic particle inspection is mostly used to detect Flaws on or near the surface The ring to ring land Clearance measureswith a calliper Gauge Depth A transverse crack can be detected by magnetic particle inspection by placing field in the direction of defect. Only for shear load applications is where an AN clevis bolt is used in an airplane. In magnetic particle inspection, a flaw that is perpendicular to the magnetic field flux lines generally causes A large disruption in the magnetic field. Intergranular corrosion may attack the grain boundaries of aluminum alloys when the heat treatment process has been improperly accomplished. The weld should taper off smoothly is characteristically what a good gas should be. The twist of a push fit Arbor connecting rod supported by parallel steel bars using a a dial gauge. The core material of Alclad 2024-T4 is a Heat-treated aluminum alloy, and the surface material is commercially pure aluminum a thickness-gaugeis the tool required for a surface plate with a narrow surface. For accuracy an aircraft repair man uses gauge blocks For a Fork wired bolt shear the lock nut with a cotton wire, while tight. The media used for a magnaflux H.Low retention/high permeation, high resistance To test minuscule defects, developer B has to have a longer soaking period. Use a metal band to sound tap the repair to identify quality A mic is most accurate to measure the stretch of poppit Perpendicular to field with a cable. Use visual,dye,metallic and ultra surface cracks and inspections to see corrosion use a telescopic gaute

combination for the center iron-based heat treated alloy for normalization fatigue crack- discontinuity to high tension for general, plastic, non-surface eddy use a ultra sonic. all types of stainllum is needed for a firewall. heat treats can can significantly fern pattern that picks up magnets. digit indicates for the alloy. single line to indicate on a bolt head. volitile petroleum base to create the developer. machinist scale, use the divider.

Basic physics

• Temperature is a measure of the kinetic energy of the molecules of any substance.

• The boiling point of a given liquid varies with is Directly with pressure

• If a double acting actuating cylinder in a 3000 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 the actuator be able to produce when retracting A = 6,000 pounds

• The ratio of the water vapor actually present in the atmosphere to the amount that would is Relative humidity

• An airplane wing produce lift 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.

• If the volume of a confined gas is doubled the pressure reduced to one half its original value

• If all or a significant part of a stall strip is missing the wing Asymmetrical lateral control at a near stall angles of attack

• If the temperature of a confined liquid is reduced the volume

• True conditions which creates a high land speed with high temp, high humitdy

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• 98 parts of dy air.

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• 4000psi pressure will be. the best set up is stall first. has hight drag, lowspeed 360 is lower. 8.9 is the force will need to saturation.