undercarriage and cooling systems

Question 1

what are the two most common undercarriage type aircraft?

Answer 1

tricycle - where they have two main wheels with a third wheel under the nose

tail wheel - two main wheels but the third wheel is underneath the tail

Question 2

what type of steering is utilised on nose wheel aircraft?

Answer 2

nose-wheeling steering which is linked to the rudder pedals so if the pilot presses the left pedal it’ll move left.

Question 3

some tailwheel aircraft have what?

Answer 3

a connection between the tailwheel and rear wheel, if there’s no connected then the tail is free to move around.

Question 4

most aircraft have brakes where?

Answer 4

on main wheels only.

Question 5

what is the most common brake used?

Answer 5

disc brakes which are activated by depressing the top of the rudder pedals.

Question 6

most light aircraft have a system where what?

Answer 6

each wheel can be braked independently of the other, which can assist when turning the aircraft. if wanting to turn left the left brae can be used as well as pushing the left rudder pedal.

Question 7

what are the precautions of tricycle aircraft? (3)

Answer 7

• maintain walking speed for taxi
• when crossing uneven ground, the propellor tips may strike the ground so crossing from an angle is suggested
• avoid taxiing anywhere where you can’t see the ground as there may be hidden obstacles that might strike the propellor (give two wingspans between you and a propellor)

Question 8

what are the precautions of tailwheel aircraft?

Answer 8

• taxi at walking speed as they have reduced forward visibility due to the higher nose.
• inherently unstable so extra care must be taken with directional control.
• if fitted with a tail skid rather than a wheel, operation on grass surfaces is recommended to reduce wear and provide with better braking.

Question 9

most aircraft are what?

Answer 9

air-cooled

Question 10

water-cooled engines have what?

Answer 10

a radiator which is extra weight due to the water. also have the disadvantage that if there’s a leak, there’ll is likely to be insufficient cooling of the engine leading to engine overheating and failure.

Question 11

air-cooled engines compromise of what?

Answer 11

things like cooling fins which increase the surface area of the cylinder and allow more area to give off the heat.

where the air is ducted around the engine such as a way to maximise cooling.

Question 12

what happens if an engine is cooled too slowly?

Answer 12

will exceed max operating temperature and damage is likely to result.

Question 13

what happens if an engine is cooled too quickly?

Answer 13

shock cools (excessive decrease in temperature) the components which can lead to damage.

Question 14

what are cowl flaps?

Answer 14

flaps on the cowl which assists the air to move through the engine bay.

The more movement, the more cooling.

Question 15

how do cowl flaps work?

Answer 15

air enters through the intake ducts at the front of the engine. some of the air comes from the propellor but most are ram air from aircraft forward speed.

ducts and baffles direct the air to where its needed for cooling.

Question 16

if aircraft is fitted with cowl flaps when are they open and closed?

Answer 16

open for taxiing and takeoff and final approach, and closed when in cruise.

Question 17

why are cowl flaps open and closed at these times?

Answer 17

because as airspeed is higher, so is the cooling effect of the ram air, so the engine needs less help to stay cool.

Question 18

what does the spinner at the front of the aircraft do?

Answer 18

helps direct airflow into the engine bay to assist with cooling.

Question 19

how is overheating avoided?

Answer 19

mindful of operating at long periods at full power and low airspeed, especially on hot days.

Question 20

how is overcooling avoided?

Answer 20

avoid overcooling which is caused by going from high power settings to idle, then perhaps opening cowl flaps if fitted, and then descending at a fast airspeed.