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Date: Thu, 12 Jan 2006 08:01:31 -0700
From: Bob White <rlwhite@comcast.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Cool Tube Muffler Sound Readings
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Hi Mark,

Yes it was.  Otherwise I would be buying a new engine right now because
of the WOT start I did last Saturday. :)  (dumb mistake)

Bob W.  (building checklists to minimize dumb mistakes)


On Thu, 12 Jan 2006 07:46:07 -0600
"Mark R Steitle" <mark.steitle@austin.utexas.edu> wrote:

> Bob,
> Was your prop installed when these readings were taken?
> 
> Mark S.  
> 
> -----Original Message-----
> From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
> Behalf Of Bob White
> Sent: Wednesday, January 11, 2006 6:00 PM
> To: Rotary motors in aircraft
> Subject: [FlyRotary] Cool Tube Muffler Sound Readings
> 
> Today I ran the engine to get the sound level readings.
>   
> Short review:
> This is the cool tube muffler built by Jerry Hey.  Each exhaust port
> has a short tube into a large round can.  The center of the can has a
> two inch tube down the center to permit cool air to aid in cooling the
> exhaust.  This tube is sealed from the actual exhaust gasses.  The
> exhaust exits the large tube thru a rectangular tube at the bottom of
> the large round can.  (photo attached)
> 
> Here are the sound level readings with the engine running at 3000 RPM
> 
> Location	A	C
> --------------	---	---
> Left Wing	98	105
> Right Wing	96	105
> Front (5 paces)	95	105
> Tail		91	103
> Pilot Seat	84	94
> 
> The A weighting cuts out the low frequencies below 500 Hz.  I have no
> idea how these compare to the typical aircraft engine.  According to
> the instruction manual, the A weighting is used to determine area noise
> levels, and C wighting is used to measure sound levels of musical
> instruments.  
> 
> I will get some higher rpm measurements after I get a little more time
> on the engine.
> 
> Coolant temps seemed to stabilize at 200F and oil at 175F with the
> engine at 2500-3000 rpm tied down and no cowling installed.  I ran it
> for around 10 minutes in this mode.
> 
> Bob W.
> 


-- 
http://www.bob-white.com
N93BD - Rotary Powered BD-4 (first engine start 1/7/06)
Custom Cables for your rotary installation -
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