Re: Q200 Prop


David J. Gall
 

That must be a node where the bending energy was focused when the prop experienced resonance.

 

 

From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Jim Patillo
Sent: Friday, May 20, 2022 4:17 PM
To: main@Q-List.groups.io
Subject: Re: [Q-List] Q200 Prop

 

Jay it was about 10” from the center of the hub on the front “meaty” part of the prop and had propagated across the grain so to speak. 

 

Jim

N46JP - Q200


From: main@Q-List.groups.io <main@Q-List.groups.io> on behalf of Jay Scheevel <jay@...>
Sent: Friday, May 20, 2022 12:52:15 PM
To: main@Q-List.groups.io <main@Q-List.groups.io>
Subject: Re: [Q-List] Q200 Prop

 

Hi Jim,

 

Just out of curiosity, was your crack on the rear or front of the blade (or both)?

 

Cheers,

Jay

 

From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Jim Patillo
Sent: Thursday, May 19, 2022 3:05 PM
To: main@Q-List.groups.io
Subject: Re: [Q-List] Q200 Prop

 

Long read.

 

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. 

 

Jim

N46JP - Q200

 

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