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TWD December

PostPosted:Sun Nov 07, 2010 4:28 pm
by met24
1. Rules of thumb: 'Prop forward, throttle back' is how I remember it -- increase RPM before increasing power, reduce power before reducing RPM. Never operate 'over square' is the other one -- never have more inches of manifold pressure than hundreds of RPMs, although there are rather more arguments with that one! I suspect it doesn't work very well with turbocharged engines.

2. The beating will have been from the two engines not running at quite the same RPM. In my admittedly tiny number of multi-engine hours I never worried about it on takeoff, then after reducing power and RPM sorted it by tweaking one propeller control when I had a few seconds to think about it. There might be quite a bit of stagger between the prop levers to get both engines at the same RPM.

3. He reduced the prop RPM without reducing the MP first. For a given throttle setting, if you reduce the prop RPM you do get an increase in manifold pressure so I can imagine wide-open throttle with 2200rpm putting MP above the redline.

2200rpm seems like a very low setting for climb as well, even if he'd reduced power first. 2400 or 2500 sounds more sensible, waiting until cruise for 2200.

PostPosted:Sun Nov 07, 2010 9:22 pm
by pands
Rev Up...Throttle Back!

Increasing the revs make sure it is the RPM lever that is set to the desired setting before increasing the MP. REV UP!
Looking to reduce the RPM setting then THROTTLE BACK first before setting the desired RPM.