para kay col8

Question 1

balances should be ___ & ____

Answer 1

accurate and reliable

Question 2

things to consider in 3d balance calibration

Answer 2

body axes, wind axes, wind axis components, velocity

Question 3

types of body axes

Answer 3

lateral, longitudinal, vertical

Question 4

3 types of forces in body axes

Answer 4

drag, lift, side force

Question 5

6 COMPONENT BALANCE

Answer 5

Lift (L), Drag (D), Side Force (Y), Rolling Moment (l), Yawing Moment (n) , Pitching Moment (m)

Question 6

LIFT FORMULA

Answer 6

C+D+E

Question 7

DRAG FORMULA

Answer 7

A+B

Question 8

SIDE FORCE FORMULA

Answer 8

F

Question 9

ROLLING MOMENT FORMULA

Answer 9

(C-D) x b/2

Question 10

YAWING MOMENT FORMULA

Answer 10

(A-B) x b/2

Question 11

PITCHING MOMENT FORMULA

Answer 11

E x c

Question 12

OTHER TYPES OF COMPONENT BALANCE

Answer 12

three component balance, two component balance

Question 13

an incredibly complicated device, much better left to engineers of balancing than to engineers of tunnels

Answer 13

wind tunnel balance

Question 14

placed outside the model, inside or outside the wind tunnel test section, always introduce some interference in the wind flow

Answer 14

external force balance

Question 15

placed inside the model, no interferences, mechanical support is always needed

Answer 15

internal force balance

Question 16

model mount of external balance

Answer 16

two strut, three strut

Question 17

model mount for internal or external balance

Answer 17

single strut, sting

Question 18

compromise between the required maximum load capability of all components and the accuracy required for minimum loads

Answer 18

wind tunnel balance

Question 19

danger in inner balance

Answer 19

model can unintentionally exceed the ability of the balance

Question 20

important to use a thorough analysis

Answer 20

external balance

Question 21

has to bear are primarily a feature of the size and speed of the tunnel test section

Answer 21

estimated loads

Question 22

if a tunnel size is doubled

Answer 22

platform and loads are increased fourfold

Question 23

four external balances

Answer 23

wire, frame, yokes and pyramid

Question 24

usually mounted inverted

Answer 24

wire balances

Question 25

why are wire balances mounted inverted

Answer 25

so the aerodynamic lift applied to the weight prevents the wires from being removed

Question 26

much less stable and flexible, used since in the early days of aeronautics, consumes a large area

Answer 26

wire balances

Question 27

these balances provide mechanisms for changing the AOA and yaw and transmit the model loads down into a system linkages

Answer 27

platform, yoke, and pyramid balances

Question 28

minimizes deflection in linkage type

Answer 28

rigid strut

Question 29

interaction loads can be reduce to a small value

Answer 29

choosing proper linkages

Question 30

can be encountered in high speed flows

Answer 30

deflections

Question 31

___ is more when three point strut support is exhibited

Answer 31

interference drag

Question 32

one of the most troublesome problems of wind tunnel balances

Answer 32

lack of rigidity

Question 33

____ may move the model from the resolving center and invalidate the moment data or nullify the balance alignment

Answer 33

deflections in the balance

Question 34

must be kept down to where they are negligible or they must be evaluated and accounted for in the data reduction process

Answer 34

deflection

Question 35

greatest source of deflection

Answer 35

mounting mechanism

Question 36

solution to mounting mechanism

Answer 36

use high-modulus elasticity materials for the strut, have a deep and stable structure

Question 37

large number of ____ are the main components of an external balance and are built to have minimal deflection under high load.

Answer 37

levers

Question 38

knife edges

Answer 38

early pivots in wind tunnel balances

Question 39

benefits of flexures

Answer 39

may be designed to withstand loads between the couples members in either direction with no loss of motion, practically frictionless and thus reduce symptoms of hysteresis, can survive treatment which is relatively harsh, practically wearproof; remain constant for an infinite period of time

Question 40

wind tunnel measurements (pressure)

Answer 40

manometer, barometer, pressure transduces

Question 41

balanced by the weight of the liquid column

Answer 41

manometer

Question 42

used to measure atmospheric pressure

Answer 42

barometer

Question 43

converts pressure to an analog electrical signal

Answer 43

pressure transduces

Question 44

why do we calibrate

Answer 44

ensure accuracy, control error, help assure precise measurement

Question 45

properties measured during calibration

Answer 45

air speed, floor angularity, turbulence measurement

Question 46

determines airspeed inside test section

Answer 46

pitot tube

Question 47

done when there is no model inside test section

Answer 47

setting the speed

Question 48

usually determined by measuring either static or total pressure

Answer 48

tunnel speed

Question 49

subscript for bellmouth or settling chamber

Answer 49

L

Question 50

subscript for the region before testing section

Answer 50

S

Question 51

usually measured throughout selected regions of the test section with the use of pitot-static tube

Answer 51

dynamic pressure

Question 52

calculated from a barometric pressure measurement, and a test-section temperature determination along w/ the equation of state

Answer 52

density

Question 53

variation of q in the working range of the jet

Answer 53

less than 0.5% from the mean, corresponds to a 0.25% variation in velocity

Question 54

has to be uniform across the cross section

Answer 54

flow

Question 55

can be calculated using sphere type and claw type yaw meter

Answer 55

flow direction

Question 56

desirable variation

Answer 56

less than +-0.10 degrees

Question 57

maximum variation

Answer 57

+-0.20 degrees

Question 58

measurement of irregularity in the flow

Answer 58

turbulence

Question 59

used to identify whether the flow is laminar or turbulent

Answer 59

reynolds number

Question 60

previously used as the primary way to measure relative turbulence of a wind tunnel

Answer 60

turbulence sphere

Question 61

common way to measure relative turbulence of a wind tunnel

Answer 61

hot-wire anemometry

Question 62

can be measured using rakes of pitot tube

Answer 62

tunnel boundary layers