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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