I'm still mystified by the widely different results builders are getting with the Hushpower. Both my planes have them. I have over 500 hours on the RV-4 muffler and it's still in good shape (minus the fiberglass which goes pretty fast). Even the Hushpower on the 20B is still OK after 90 hours. Admittedly, i do spend a lot of time cruising around at low throttle but every takeoff & climb out is at WOT.
Only news on the 20B testing is that I found my fuel flow calibration was off so it wasn't getting as good a fuel burn numbers as I thought. Still in the same ball park as the Renesis at similar airspeeds. At sea level it gets pretty hungry above 215 mph though. There the numbers look like what you would expect of a Lyc. IO - 540.
Tracy
Sent from my iPad
Hi Brian,
I have flown with two Hushpower mufflers for the past 8
years. So far no restrictions, although the non-metallic sound deadener
has long departed. Also by having one muffler per exhaust, it may suffer
less of a beating.
YMMV
Ed
Sent: Wednesday, May 16, 2012 12:25 AM
Subject: [FlyRotary] Re: High EGTs
And I am running a Hushpower, I run a bore scope up it today and the exit
cone looked completely intact. No way to check out the entrance cone without
taking the exhuast system apart, which is possible but a PITA. Is a
Hushpower considered restrictive?
Brian Trubee
-----Original
Message----- From: Bill Bradburry < bbradburry@bellsouth.net> To:
Rotary motors in aircraft < flyrotary@lancaironline.net> Sent: Tue, May
15, 2012 8:38 pm Subject: [FlyRotary] Re: High EGTs
Mark,
Now you have gotten me
concerned! I changed the muffler and that didn’t seem to have any effect
on the EGTs, so I don’t think that is the cause, but I don’t want to damage any
orings. What were the temps you were seeing when the orings were
damaged?
Bill
From: Rotary
motors in aircraft [mailto:flyrotary@lancaironline.net]
On Behalf Of Mark
Steitle
Sent: Tuesday, May 15,
2012 10:18 PM
To: Rotary motors
in aircraft
Subject:
[FlyRotary] Re: High EGTs
Brian,
I had high EGT's at one time. Turns out it was due
to an overly restrictive muffler. The high EGT's damaged the o-rings
resulting in an engine overhaul. Could this possibly be at the root of
your high EGT readings?
Mark S.
My engine is now
running just the way it should, temps were 180 or lower on a 75 degree day, but
my EGTs have always been high, really high- above 1800 almost all the time. I
think it may be a calibration issue. My egt sensors are about 3 inches
downstream of the exhaust ports, and I am using Tracy's EM2, calibrated at the
stock settings. When the engine is stone cold, the egt's read about 230 degrees,
which I assume is normal because the sensors are meant to operate at a much
higher temperature. Any thoughts?
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