Quiet Cans and Pipes, JMB, BMB, ESCOMPOSITES, KS?
04-25-2007, 08:24 AM
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RE: Quiet Cans and Pipes, JMB, BMB, ESCOMPOSITES, KS?
Answer JMB makes two types of cans -one is muffled ONLY and very numb to length -easy to setup and quiet .
The other is a tuned setup and requires longer header .
The other is a tuned setup and requires longer header .
Designated e.g. M 60/60/270 or M 80/70/300.
Which type is this?
Magne
04-25-2007, 03:26 PM
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RE: Quiet Cans and Pipes, JMB, BMB, ESCOMPOSITES, KS?
ORIGINAL: flyinrazrback
joel, with the 18" baffled pipe, I found with the DA 50 the best header for all around flying was 12" long, using a Vess 23A at 7100-7120. Perfect midrange and great top end power.
joel, with the 18" baffled pipe, I found with the DA 50 the best header for all around flying was 12" long, using a Vess 23A at 7100-7120. Perfect midrange and great top end power.
06-12-2007, 04:44 AM
#78
RE: Quiet Cans and Pipes, JMB, BMB, ESCOMPOSITES, KS?
Thought I would paste this over here from the noise issue thread on the MVVS Support forum for interest:
I have now repeated these tests in the open air of my flying field and not in the garden as before the results are supprising, I did not expect the reflected sound off the surrounding trees to make that much difference to the sound volume.
MVVS 58 Pro, 22x10 3W prop, 5900rpm J-TEC large pitts silencer 90DB at 7 Meters.
MVVS 58 Pro, 22x10 3W prop, 6300 rpm MTW 75K with 25mm dia 210mm manifold, 83 DB at 7 Meters
The open area took 2Db's off the pitts silencer and 3Db's off the cannister, I suppose that is logicall as the lower sound would have a lower reflective index? therefore an extra Db off. I don't think I have mentiond before this engine is mounted on Isolation mounts to help lower sound atenuation through the airframe.
Mike
I have now repeated these tests in the open air of my flying field and not in the garden as before the results are supprising, I did not expect the reflected sound off the surrounding trees to make that much difference to the sound volume.
MVVS 58 Pro, 22x10 3W prop, 5900rpm J-TEC large pitts silencer 90DB at 7 Meters.
MVVS 58 Pro, 22x10 3W prop, 6300 rpm MTW 75K with 25mm dia 210mm manifold, 83 DB at 7 Meters
The open area took 2Db's off the pitts silencer and 3Db's off the cannister, I suppose that is logicall as the lower sound would have a lower reflective index? therefore an extra Db off. I don't think I have mentiond before this engine is mounted on Isolation mounts to help lower sound atenuation through the airframe.
Mike
