Subject: COZY: Sound Level om Cozy From: mbeduhn@juno.com (Mark W Beduhn) Date: Thu, 29 Jan 1998 21:25:51 EST Hi everyone! I was doing sound level measurements at work, and I thought it would be interesting to measure the level in my Cozy. I used a sound level meter that was "A" weighted. Here is the short summary: 2500 rpm, 173 kts, 5000ft, 90db 2650 rpm, 183 kts, 5000ft, 92db I have absolutely no idea how these numbers relate to other general aviation planes. Mark Beduhn Cozy IV N494CZ (any excuse to go flying is good enough) _____________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com Or call Juno at (800) 654-JUNO [654-5866] Date: Fri, 30 Jan 1998 01:23:25 -0500 From: Dave Black Subject: COZY: Re: [canard-aviators] Sound Level om Cozy Mark W Beduhn wrote: > I was doing sound level measurements at work, and I thought it would be > interesting to measure the level in my Cozy. I used a sound level meter > that was "A" weighted. Here is the short summary: > > 2500 rpm, 173 kts, 5000ft, 90db > 2650 rpm, 183 kts, 5000ft, 92db > > I have absolutely no idea how these numbers relate to other general > aviation planes. Mark, I've done a few measurements with my "A" weighted meter as well: Dodge Caravan (65mph) 93dB LongWing Velocity FG (cruise)* 98dB Piper Warrior (cruise) 102dB ShortWing Velocity FG (cruise) 103dB Beech Bonanza (cruise) 104dB Radial arm saw (1 foot away) 108dB Unfortunately I did not record the actual engine RPMs and airspeeds on the aircraft I checked. But all are in the vicinity of 2400RPM @ 3500 ft. *The LongWing Velocity had sound insulation installed, and cruises slower than the ShortWing. Assuming both our meters are properly calibrated, your Cozy sure sounds very quiet. Did you install any special soundproofing? Dave Black Shortwing Velocity RG From: "Fred I. Mahan" Subject: COZY: Re: Sound Level on Cozy Date: Fri, 30 Jan 1998 07:54:06 -0500 Mark W Beduhn wrote: I was doing sound level measurements at work, and I thought it would be interesting to measure the level in my Cozy. I used a sound level meter that was "A" weighted. Here is the short summary: 2500 rpm, 173 kts, 5000ft, 90db 2650 rpm, 183 kts, 5000ft, 92db Dave Black wrote: I've done a few measurements with my "A" weighted meter as well: Dodge Caravan (65mph) 93dB LongWing Velocity FG (cruise)* 98dB Piper Warrior (cruise) 102dB ShortWing Velocity FG (cruise) 103dB Beech Bonanza (cruise) 104dB Radial arm saw (1 foot away) 108dB To add to the pot -- in Canard Pusher #15, Rutan reported the following: VariEze with no mufflers @ 75% power -- 98.5 dB VariEze with mufflers @ 75% power -- 96.5 dB VariEze with no mufflers @ 50% power -- 95 dB VariEze with mufflers @ 50% power -- 93.5 dB Cessna 150 @ 75% power -- 93.5 dB Piper PA28-140 @ 75% power -- 91dB All VariEze readings were taken from the front seat, with the back seat being ~ 2dB louder. He didn't say which meter weighting was used. Based on the small reduction with mufflers, he decided not to incorporate them. Fred in Florida Long-EZ N86LE Defiant project #137 From: wilhelmson@scra.org Date: Fri, 30 Jan 1998 09:27:23 -0500 Subject: Re: COZY: Sound Level om Cozy Mark: You will find that the sound levels you measured are about the same as general aviation aircraft. However; the frequency spectrum is much different. The Canard aircraft flying at 180k has a much higher frequency spectrum (Wind noise) than a Cessna 172 flying at 100k. Measure the noise level in the COZY at 100k and then compare. Jack Wilhelmson CZ711. Subject: COZY: Re: [canard-aviators] Sound Level om Cozy From: mbeduhn@juno.com (Mark W Beduhn) Date: Sat, 31 Jan 1998 12:07:42 EST Dale, It is so easy to determine TAS with my Rock Mountain Micro encoder (flip of a switch) that I don't use IAS when I am doing any testing. I would guess about 10 kts lower though. Mark Beduhn Cozy IV N494CZ On Sat, 31 Jan 1998 01:19:39 EST NICEEZ@aol.com writes: >In a message dated 98-01-30 00:15:54 EST, mbeduhn@juno.com writes: > ><< Here is the short summary: > > 2500 rpm, 173 kts, 5000ft, 90db > 2650 rpm, 183 kts, 5000ft, 92db > >> >I take it these are Kts True AS. What is it indicated KIAS ? >Dale > _____________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com Or call Juno at (800) 654-JUNO [654-5866]