REFLECTOR: Enhanced photos Cozy Loss of Catto Prop

michalk michalk at awpi.com
Wed Dec 20 14:36:01 CST 2006


Post them to the gallery?

Jim Agnew wrote:
>  
> I just received the following note from Craig Cato and I'm posting it 
> since it contains some important information.
>  
> I took five of the Cozy pictures and enhanced them increasing their 
> sharpness and contrast, the failure mode is clearly visible.  The center 
> flange looks like it is threaded as do the drive studs and one stud (the 
> one opposite the last bolt) looks like the prop was moving almost 1/4".  
> Sam DaSilva looked at the original pictures and we were speculating the 
> the prop finally departed the one remaining bolt and was slung away by 
> the remaining bolt which caused the bending of the bolt attachment stud.
>  
> I can't attach the 5 pictures due to their 1.5MB each size so if anyone 
> has a way to post them let me know. 
>  
> Jim
>  
> 
> ----- Forwarded Message ----
> From: Craig Catto <cattoprops at cdepot.net>
> To: Jim Agnew <Jim_Agnew_2 at yahoo.com>
> Sent: Wednesday, December 20, 2006 11:57:00 AM
> Subject: RE: Enhanced photos
> 
> Jim,
> OH my gosh!!!.. thanks for the pics!,,  
> One thing sticks way out to me, and have seen spinner failures due to 
> this and other props that have worked due to this. From what I see, it 
> looks like there is fabric imprinting on the face of the extension.  IF 
> a composite spinner bulkhead was used, I have high suspicions this was a 
> culprit.  I do not recommend a composite bulkhead ever be used 
> in-between the power transfer surfaces, extension to propeller.  I have 
> also seen painted aluminum bulkheads on many installations that have 
> shown signs of working and do not recommend that the aluminum area of 
> power transfer be painted in any fashion.
>  
> The problem is the resin in a spinner bulkhead and or paint on a 
> aluminum bulkhead usually will not handle the heat associated with this 
> power transfer if there ever becomes any small movement.  Like rubbing 
> your hands together, friction, amplify this by thousands in frequency 
> and the heat generated in a very short period of time will break down 
> the resin and or paint  in the area of power transfer.  Once this 
> happens, you now have a lubricant in-between the extension and 
> propeller, and the inevitable will happen. With the composite bulkheads, 
> once heat reaches a point it will flow ever so slightly causing a 
> dramatic reduction in bolt torque!
>  
> I have not talked with Zeitlin or seen the article of this incident yet, 
> only pictures sent to me from Jim Agnew. These pictures of the fabric 
> imprint of the possible use of a composite bulkhead raised loud alarms 
> to me.  If anyone is using this type of spinner bulkhead, I do not 
> recommend it be used.  I personally have seen to many of them that have 
> shown signs of working and causing torque values to reduce. And 
> recommend on a aluminum bulkhead that the paint be removed in the 7" 
> diameter area of power transfer.
> On the composite bulkheads, you can either replace it with an aluminum 
> one, or cut out the inner area and rivet on an aluminum circular plate.
>  
> Jim, if you could please post this immediately I would sure appreciate it.
> Regards,
> Craig Catto
>  
>  
>  
>  
>  
> -----Original Message-----
> *From:* Jim Agnew [mailto:jim_agnew_2 at yahoo.com]
> *Sent:* Wednesday, December 20, 2006 8:09 AM
> *To:* Craig Catto
> *Subject:* Enhanced photos
> 
>     Hi Craig, I enhanced 5 key photos so you can see them better.
>      
>     Jim
>      
>     James F. Agnew
>     Jim_Agnew_2 at Yahoo.Com
>     Tampa, FL
>     Velocity 173 Elite Aircraft Completed & Flying
> 
> 
> 
> 
> 
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