Re: Q200 Prop
Sorry for the confusion. When I was referring length and pitch of props for standard and pumped up 0200’s on a Q, I was using Bernie Warnke "Almost Constant Speed" and Craig Catto props for reference.
At first, I ran Bernie’s 60/66 prop on my 100HP Continental engine. It had good climb and cruise qualities. Then I put on new polished and ported Superior Cylinders with 9:4.1 compression, which equates to around 118-120HP. The Warnke was still smooth and now I could run it up in the 3200 RPM range wher HP is made. It was great in climb cruise and I could control the RPM's. At high RPM and Speed, the plane harmonics were balanced and the ride was smooth. Then it happened at about 250 hours. I found cracks across the prop wood ply near the hub on one side. May have failed because of overspeed or hard pull ups at air shows, I don't know. So 60/66 Warnke is retired and now resides on the wall at home.
Craig Catto was a friend and neighbor, so I had him take a look. I gave him some parameters and he suggested the prop now be a 60/72, to get it to absorb the HP. and max the RPM's @2,900. I agreed.
I couple weeks later he dropped off a beautiful 60/72 black prop with white tips. I flew it the first time and really liked the construction with wood laminated ply wrapped with glass and metal bulkheads on both sides. It performed as he predicted. I've had it on the plane since.
N46JP - Q200
From: main@Q-List.groups.io <main@Q-List.groups.io> on behalf of Jay Scheevel <jay@...>
Sent: Thursday, May 19, 2022 12:43:58 PM
To: main@Q-List.groups.io <main@Q-List.groups.io>
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.
From: main@Q-List.groups.io <main@Q-List.groups.io>
On Behalf Of Jay Scheevel
The last remaining "Black Art" in aviation. Beware of its practitioners 😉
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: