20. Propellers

Question 1

A propeller converts engine torque into (thrust / horsepower).

Answer 1

thrust.

Question 2

To ensure that it operates at an efficient angle of attack over its whole length, a propeller blade is (twisted / straight).

Answer 2

twisted.

Question 3

The blade angle is that angle between the chord line and the (plane of rotation / direction of flight).

Answer 3

plane of rotation.

Question 4

The plane angle is greatest near the (hub / tip).

Answer 4

hub.

Question 5

The fastest moving part of a rotating propeller is at the (hub / tip).

Answer 5

tip.

Question 6

The total aerodynamic force produced by a propeller is normally resolved into two components: one in the direction of flight called …….. and the other in the plane of rotation called propeller ……..

Answer 6

thrust; torque.

Question 7

At constant rpm, engine torque is being balanced by …….. torque.

Answer 7

propeller.

Question 8

If you place a fixed-pitch propeller aircraft into a dive and leave the throttle set, engine rpm will (increase / decrease).

Answer 8

increase.

Question 9

Most of the thrust produced by propeller comes from the area of the blades at around (50% / 70% / 90%) radius.

Answer 9

70%

Question 10

With a fixed-pitch propeller at a given rpm, there will be (one / several) true airspeeds at which the propeller will operate at its most efficient angle of attack.

Answer 10

one.

Question 11

For operation at high rpm and relatively low airspeeds, the most efficient propeller would have a (fine / coarse) pitch.

Answer 11

fine.

Question 12

For operation at relatively high airspeeds and low rpm, the most efficient propeller would have a (fine / coarse) pitch.

Answer 12

coarse.