[NSRCA-discussion] Broken Hyde mount beams (my fault)

[John Pavlick]

Interesting. Well, call me paranoid but on my engine installations, I use 
bolts that are about 1/4" longer than required and I put a nylock on them. I 
always check them during routine maintenence and I've never found a loose 
one. Of course I don't have any with 1000 flights on them yet! <LOL>

John Pavlick
http://www.idseng.com

----- Original Message ----- 
From: "Lance Van Nostrand" <patterndude at tx.rr.com>
To: "hydesoftmounts" <hydesoftmounts at mymailstation.com>; "NSRCA Mailing 
List" <nsrca-discussion at lists.nsrca.org>
Sent: Monday, April 23, 2007 8:56 PM
Subject: [NSRCA-discussion] Broken Hyde mount beams (my fault)


> [pattern guys, hope you find this interesting/helpful.  I had an aluminum
> beam break on my CR mount. The mount had about 1000 flights.  I sent it to
> Hyde Mounts for analysis, not knowing if he'd really be interested.  Merle
> responded right away with this. --Lance]
>
> Merle,
> I will gladly pass this on.  I'm glad you got to looking at it.  It was 
> not
> obvious why it would break at that location.  I thought those impressions
> were due to over tightness.  I never noticed the screws being loose, but 
> it
> makes more sense that the impressions were made by a loose engine than a
> tight one.  this has now become a much more interesting problem.  Your
> recommendation to check and retighten as part of periodic maintenance is a
> good suggestion and this experience proves it.
>
> It is always great to work with you.  Some businessmen wouldn't want this
> information distributed, so your commitment to making the best product
> possible and your openness should be shared along with this information.
>
> --Lance
>
> ----- Original Message ----- 
> From: "hydesoftmounts" <hydesoftmounts at mymailstation.com>
> To: <patterndude at comcast.net>
> Sent: Sunday, April 22, 2007 6:38 PM
> Subject: Beams
>
>
>> Hi Lance,
>>
>> Its been a windy weekend here - for sure!
>>
>> I now know why the beam broke.  Over the years I have only had a few
>> aluminum beams break that were not crashed or impacted.  I have saved the
>> broken beams and never fully understood or conducted an analysis as to 
>> why
>> they had broken for only a few and not others.  After receiving your
>> broken beam I studied the other few I have saved.  In each case the 
>> broken
>> beam had a wear impression on it that was located exactly where the rear
>> of the engine lug caused such impression/depression by being permitted to
>> operate with the screw(s) being slightly loose.   The wear impression
>> obviously causes "work hardening" of the aluminum and the breaks have
>> always been at the used tapped hole or with some beams at the location of
>> the unused tapped hole located directly under the position where the rear
>> of the engine lug contacts the beam.  The beam breakage does not occur at
>> the position of the lightening holes which removed considerably more beam
>> material - breakage
>> at the position of the lightening hole would be most obvious - but this 
>> is
>> not the case.  "Work hardening" is the only reasonable conclusion.
>>
>> Even nylon composite beams, that have not been crashed or impacted, and
>> that have been properly drilled/prepared, can also break at the position
>> of the "wear impression" that is created if permitted to operate with the
>> screws loose.
>>
>> Over the years I occasionally ran an ad in the K-Factor that advised Hyde
>> Mount users to check the tightness of fasteners/screws.  Another problem
>> some have had is that the mount may loosen on the firewall.  In all cases
>> the loosening was caused by insufficient tightening and also over time 
>> the
>> blind nuts compressed the firewall and permitted the mounts to get loose
>> on the firewall.  The key to preventing this is to tighten screws very
>> tight and also ensure "hard points" at all bolting locations.
>>
>> My suggestion is to ensure tightness of fasteners - and use a "T" handle
>> type allen wrench and not be timid when tightening - securing screws VERY
>> tightly, to torque specs, will not damage any part of a Hyde Mount!!!
>>
>> I am not on the internet, nor do I have access to the NSRCA "chat room"
>> site.  I would appreciate it if you would pass this information along -
>> others may benefit.
>>
>> Thanks,
>>
>> Merle
>
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