You do have to "temper" this information a bit (so to speak.) It is more than likely that your seals became VERY hot in the last few minutes of engine operation.

At 07:25 PM 5/5/2005, you wrote:

Thanks Bob,
 
Verrrryyyyy Innnteerreessstinnngg.  So it does appear that my seals were "soft" at least in comparison of the Hurley seals of Rusty.  Only one area of the six areas you tested on my seal was above Rockwell 30 - whereas 11 out of the 12 areas tested on Rusty seal were above Rockwell 30.  Also one hit on my seal indicated a Rockwell hardness of only 23.1. I am not knowledgeable enough to know if those difference are a major significance or not - but it does show the metal in my seal of less hardness than that of Rusty.
 
  Your findings plus (as you noted) the ridge of metal gouged out of the seal by apparently its rubbing against the top edge of the apex slot indicates to me that my seals were likely less that they should have been.
 
Appreciate you taking the time and trouble, Bob.  Should have sent you one of Tracy's to test as well - but mine were all in the engine {:>)
 
Best Regards
 
Ed

----- Original Message -----

From: Bob Perkinson

To: Rotary motors in aircraft

Sent: Thursday, May 05, 2005 8:28 PM

Subject: [FlyRotary] Seal Hrdness

OK here are the HARD numbers, but first let me give some detail on what equipment I used and how the tests were conducted.  The equipment used was an Equotip 2 portable hardness tester, manufactured by Proceq Sa, Switzerland.

 

The following is an explanation snagged from there web site.

 

?The EQUOTIP 2 metal hardness tester is a light weight, yet powerful portable hardness tester for all metallic materials.  It measures the Leeb value (L) for materials, which is a ratio of the impact velocity to the rebound velocity.  This L value is then converted to standard hardness scales such as Rockwell, Brinell, Shore, and Vickers using conversion tables stored in the display unit and generated from the original Leeb block.?

 

I had mentioned in a previous post that the numbers that I generated when testing the stock seal were jumping around.  Well like the old saying says, ?when all else fails read the instructions.?  The seals are not thick enough to be tested without providing a good support, in fact they are at the minimum thickness for the impact device that is used.  So the seals were coupled to a heavy support base for the test.

 

The seals were tested in three locations on each side, the straight side end, center and the corner seal end.  Each set of figures represents 3 impacts, the first figure is the LOWEST ?L? value in the series, the second is the HIGHEST ?L? value, the third is the RANGE the forth is the MEAN ?L?, the fifth is the HARDNESS.  In the first series, ?L? value is converted to Brinell hardness, in the second series ?L? is converted to Rockwell.

 

 

Min

Max

Range

Mean

Hardness Brinell

Rusty Duffy

 

 

 

 

 

Side 1

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