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Question Manifold pressure first or Propeller first - after takeoff?

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Neal

Forums Chief Pilot
Staff member
Joined
Oct 31, 1996
Posts
743
Type aircraft owned
Carbon Cub FX-3
Base airport
KFCI
Ratings
COMM, IFR, MEL, SEL
So you takeoff, prop and manifold are full forward, 2700 RPM check. Now you want to bring the prop back to 2500 RPM to reduce noise, etc.

Do you bring the manifold back first, such as to 25 inches? Or do you leave the manifold full forward and bring the prop back to 2500?

Story:

I took a fellow cub owner flying with me a few months ago and he noticed I was bringing the prop back first. "Aren't you supposed to pull manifold before prop?" Hmm, I thought, yeah, so I changed. I knew this and I'm not sure why I was doing it this way.

So I go to a seminar at OSH 2024 with Mike Busch (Savvy Aviation) giving a talk, can't remember the name of the seminar but it was good although I tend to avoid his stuff as they are so long and chatty. But this one was good AND one thing he mentioned is to leave the manifold full forward after takeoff and bring the prop back such as above. The reason is during climb if you reduce engine power it will cause the engine to work harder and end up running hotter. Hmmm, maybe that's what I had heard in the past and why I was doing it the way I was.

So now I'm wondering which to do. I've also heard about and researched flying "over squared" which is an interesting concept and you can see that with engines such as mine, a Lycoming IO-360 (essentially) you can run it 5 inches over squared, i.e. 25 inches 2000 rpm for example.

So what is your power reduction technique on climbout post takeoff? Or any climb for that matter?
 
Interesting Neal. I've been out of pistons for a minute and know zero about your plane. But I remember over squared as being bad and a way to kill an engine that was designed for it.

Found this video from Savvy on Over Squared flying

 
 
Interesting, I pull power back first. I guess because of the over square idea drummed into my head. Which brings me to another tangent - How do you do it in Europe, metric system and all?
 
On the climb to cruise, I leave MP full and back off the prop a bit for noise and vibration,

Yay Savvy.
 

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