Re: Q200 Prop


Martin Skiby
 

Jay, 

Now you made my head hurt!!!  But that is great info.

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From: "Jay Scheevel"
To: main@Q-List.groups.io
Cc:
Sent: Thursday May 19 2022 12:44:04PM
Subject: Re: [Q-List] Q200 Prop

To illustrate just how complicated fixed-pitch wooden propeller performance can be, even on a simple flight, here is a plot of TAS (kts) vs. RPM for my plane for one leg of a cross country flight from OSH to Austin MN, using only TAS values greater than 100 kts.

 

The color of each point is vertical speed in ft./min. (color scale at the bottom of the plot). The green-to-red points are where the prop is loaded during short climbs or level cruise and the blue points are when the prop is unloaded during short descents. The RMA linear-fit slope (solid line) says that my prop has 65 inch pitch. Prince says I have a 62 inch pitch. As you can see the real behavior of the prop is much more complicated, because it changes its pitch continuously due to elastic flexing of the blades, which depends on power setting, rpm and loading.

INBOX1344992955ca912aba0f03916cf19c9f2eb

 

From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Jay Scheevel
Sent: Thursday, May 19, 2022 1:08 PM
To: main@Q-List.groups.io
Subject: Re: [Q-List] Q200 Prop

 

The last remaining "Black Art" in aviation. Beware of its practitioners 😉

 

Cheers,

Jay

 

-----Original Message-----
From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of David J. Gall
Sent: Thursday, May 19, 2022 12:58 PM
To: Michael Dunning <dunningme@...>
Cc: main@q-list.groups.io
Subject: Re: [Q-List] Q200 Prop

 

Michael makes an excellent point about comparisons between props. There is much, much more to props than just the diameter and pitch.

 

> On May 18, 2022, at 6:39 PM, Michael Dunning <dunningme@...> wrote:

>

 

 

 

 

 

 

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