Propeller Sense A.M. PAMPHLET 153 1st edition, June 1943 2nd, revised edition, March 1944 This pamphlet was prepared in the Ministry of Aircraft Production and issued by the Air Ministry, Department of the Air Member for Training it comprises some hints for pilots in Service Flying Training Schools, Advanced Flying Units, Operational Training Units, and Squadrons. INTRODUCTION The aim of this pamphlet is to give you an insight into the working of the constant-speed variable-pitch propeller, which is now used almost universally on advanced trainers and operational aircraft. You may find a little accurate knowledge of how the thing works will help you to assimilate the rather bald advice you will find in Pilot’s Notes: it is easier to absorb instructions when one can seethe reasons behind them .In Part I, the principle of the propeller is discussed with special reference to blade angles, angles of attack and advance, leading up to the purpose of variable pitch. This is probably the heaviest going. If it should prove too heavy, don’t let that discourage you from having a goat Part II and comeback to Part I later. Part II introduces the constant-speed unit, which relieves the pilot of the trouble of continually adjusting pitch to suit varying flight conditions, while still leaving him in control of r.p.m. independently oj boost. It leads up to some practical conclusions that every pilot should have thoroughly soaked into his sub-conscious. Part III is about feathering, and is of special interest to the actual or prospective pilot of multi- engine aircraft again this part leads up to some practical advice. Part IV tells you something about the two-pitch propeller, about ‘positive coarse pitch', and about the special ‘manual’ control of electric propellers. Part V takes you through an imaginary flightJ telling you what to do with your propeller control and, why you should do it. It is not the purpose hereto tell you all about propellers. Precise handling instructions will be found in Pilot’s Notes General, and descriptions of the ''works' in the propeller manuals. This pamphlet is an introduction only.