Chap 13: Control Cables

Question 1

why are cables used?

Answer 1

strong, lightweight & flexible
no backlash (precise control)

Question 2

problems with cables

Answer 2

tension must be adjusted regularly due to stretching, temp. changes, wear
tension increase in high alt.
only pulling force

Question 3

control cables materials

Answer 3

galvanized carbon steel (has zinc coating & greasing to prevent corrosion)
corrosion resistant wire (stainless steel)

Question 4

types of control cables and its configuration

Answer 4

non-flexible cable (1x7) (used in straight portions)

flexible cable (7x7) (not too sharp bends)

extra flexible cable (7x19) (strong and flexible)

Question 5

smallest size cable that can be used in a primary control system is

Answer 5

1/8” dia

Question 6

2 types of fabrication for cable assembly

Answer 6

swaging (newer)

nicropress

Question 7

types of end fittings

Answer 7

threaded end, fork/eye end - used for connecting cable to turnbuckle/bellcrank

ball end terminals - attaching cables to quadrants or space limited places

Question 8

what is swaging and its process

Answer 8

for maximum cable loads
strength of swaged cable terminal is 100% of cable strength
go/no go gauge (check for tolerance)
proof test

Question 9

nicopress process and sequence of nicopress

Answer 9

copper sleeves used to full rated strength near the thimble (circle of wire)

sequence: 3-1-2
1 - middle of 2 wire
2 - inner most (nearest to the circle)
3 - outer most (furthest form circle)

Question 10

proof test reason and loads for different standards

Answer 10

ensure end fittings are secure
to pre-stretch cables

proof-load for swaging:
American - 60% rated breaking strength (hold for 3 mins)
British - 50% of rated breaking strength

Question 11

what are turnbuckles used for

Answer 11

connect cables or rods and adjust them for length and tautness

Question 12

Celsius to Fahrenheit conversion

Answer 12

(C * 9/5) + 32 = F

Question 13

Tensiometer purpose & placement of tensiometer

Answer 13

check and measure tension existing in loaded cable

(not to be taken near pulleys/turnbuckles

Question 14

methods to safety turnbuckles

Answer 14

single/double wrap (with wires)

clip locking

Question 15

types of guides and its purpose

Answer 15

fairleads, grommets, pressure seals

used to protect cables by preventing them from rubbing against metal parts
used as supports to reduce cable vibration

should not deflect the cable more than 3deg

Question 16

pulleys, sectors, bell cranks purpose

Answer 16

pulleys: change cable direction and allow cable to move with minimum friction

sectors/quadrants: used with control stick to impart force and motion

bell cranks

Question 17

2 common flexible remote control systems

Answer 17

bowden cables (light pull, returned by spring)
teleflex control systems (push and pull, stronger)

Question 18

push/pull rod systems, purpose & inspection

Answer 18

used for helicopter control

eliminates varying tension and permits transfer of compression/tension stress

checked for:
bowed rods
elongated fork ends holes or beginning of shear