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LAdamson

Constant speed prop operation q

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Hi guys,I'm confused on the correct procedure for operating constant speed prop aircraft in various flight configurations.I understand specific manifold pressure/rpm settings are specific to the aircraft, I just need guidance on general operation.First correct me if I'm wrong:takeoff - max rpm, max manifold pressure cruise climb - performance charts - generally the rpms and manifold pressure are pulled backcruise - performance charts - generally the rpms and manifold pressure are pulled backHere's where I get confused- cruise descent - reduce manifold pressure only, or reduce rpms AND manifold pressure? approach config - example - in a Cessna 177 - reduce from cruise speed to approach speed of say, 100kts, reduce manifold press only, or BOTH manifold pressure and RPM setting?and finally - final approach - I've seen conflicting opinions on whether you should use maximum RPM's - some saying it depends on noise abatement procedures, others saying it's just not necessary. Thanks for any help.

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Cruise Descent and Approach - If you had already pulled the rpms back when setting cruise, there is no need to pull them back further in descent. The cruise setting is fine. What you want to avoid is low manifold pressure and high rpms, which could increase wear on the engine.Final - The reason people set max rpm on final is to be prepared for a go-around. In a training environment, that is probably a good idea. If you are flying day in and day out on non-training reasons, then increasing the rpms on final causes a brief uncomfortable jerking motion on the aircraft and increases noise. Which one you do should depends on the flight instructor you are humoring, the procedures spelled out by the company you fly the plane for, or your own personal preference, whichever situation fits you.

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>You need constant speed props for constant speed and I don't>think the Skylane has those. Most Turboprops will though.>That "blue" knob in the lower middle of the panel---- is the constant speed prop knob ----- in this Cessna 182 Skylane.http://skylane.cessna.com/avionics.chtmlL.Adamson

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Other uses for high rpm setting on final, is to get the prop acting as a good airbrake. This allows for high approaches & a quick descent without building up airspeed. L.Adamson

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