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  • q2022,10477

    Hi,got a couple of question`s.On 2022 would`nt the spring push the blade to max pitch ie90/85 degress?says lowest pitch and on 10477 thought the vents were air scoops under each wing but but answer says on top of fuselage?

    Thanks PT.

  • #2
    Q2022, my Jepp book has this to say,

    On a single engine non-feathering propeller there are no counterweights, so boosted oil pressure is used to turn the blades to coarse, and blade CTM [centrifugal turning moment] and a light spring turn the blades to fine.
    None of the answers I can see actually match.

    Whereas it seems the full feathering type has a counterweight so feathering is achieved...

    via the spring and counterweights attached to the blades once the oil pressure has been relieved through the constant speed unit.
    Answer though appears to be "move to lowest pitch position via centrifugal force and/or spring force"


    Q10477 - I think you might be confusing either water or fuel vents fitted to light aircraft with vent-surge tanks fitted to large aircraft? In any case it got me also today, can't seem to interpret from book to to question to answer.
    Former Full-Time ATPL (A) Student (Atlantic Flight Training, Coventry)
    ex-ATP QB Subber
    CPL/IR/MCC (passed) at EGBO Halfpenny Green


    • #3
      Cheers mate!Guess its wait and see time


      • #4
        No takers?


        • #5
          Q12022. 10477

          Hi pipertommy

          Neil is correct with his explanation from his jepp notes for Q2022. The inportant point to note in the question is that it is on a single engine aircraft no feathering. In this instance the design feature is to ensure the propeller fines off (low pitch) to allow a windmill air start if required without having to dive the aircraft to a very high speed, which would be the case if the prop went to coarse pitch.

          On multi engine aircraft the propeller is designed to coarsen to reduce drag and reduce assymetric thrust forces.

          Q10477 is i believe really a helicopter AGK question. Fixed wing vent systems are normally vents on the wing. If you take fuel out of a tank you must let air into it to prevent the tank being damaged and to ensure positive fuel flow. I believe you are confusing this simple vent system with the pressue vent system of the larger jet aircraft.

          John H


          • #6
            Thank you

            Thanks John!Cleared that one up