Date: Mon, 01 Dec 1997 09:21:42 -0600 From: "Joseph H. Hart IV" Subject: COZY: (no subject) I got my first ride in a Mark IV this weekend thanks to Mike Davis of Leitchfield, KY. Great plane, great pilot, great fun! Many thanks to Mike. During the ride, I got to thinking, albeit prematurely, about interior noise and soundproofing. My question is: Has anyone figured the interior surface area (minus canopy and windows) of the plane or is anyone who remembers their calculus willing to do so? I want to figure out how to get the most noise reduction for the least amount of weight and certainly the area to be covered is a serious consideration. Also, has anyone taken any sound measurements on their plane? Ideally, I'd like measurements without any interior finishing and with various amounts of sound-deadening materials. Thanks in advance for any info. Jody Hart New Orleans, LA jodyhart@communique.net From: Marc J. Zeitlin Subject: COZY: Noise reduction Date: Tue, 2 Dec 97 9:33:14 EST Jody Hart writes: > During the ride, I got to thinking, albeit prematurely, about >interior noise and soundproofing. > Also, has anyone taken any sound measurements on their plane? >Ideally, I'd like measurements without any interior finishing and with >various amounts of sound-deadening materials. After seeing a bunch of Velocity's and COZY's with fancy, noise-proofed interiors (which are beautiful, but weigh a LOT), I've got to believe that the cheapest, lightest form of noise reduction is a good set of ANR headsets. You'll NEVER get the noise level as low (with fabric and foam) as a good set of headsets will get it. For $400, you can get a Lightspeed ANR set which worked great for me in the back seat of Lee Devlin's L.E. Now, if you're going to go the fancy interior route anyway for aesthetics, then certainly reducing noise with the same material is a good idea, but personally, I wouldn't try that as a first cut at reducing noise. My $0.02. -- Marc J. Zeitlin Email: marcz@an.hp.com by InfoAve.Net (PMDF V5.1-8 #23426) with SMTP id <01IQP5SXKC0C91ZQJX@InfoAve.Net> for cozy_builders@hpwarhw.an.hp.com; Tue, 2 Dec 1997 12:36:02 EST 02 Dec 1997 10:02:57 -0500 (EST) Date: Tue, 02 Dec 1997 09:51:38 -0500 (EST) From: Nick J Ugolini Subject: COZY: Noise reduction Marc >I've got to believe that the cheapest, lightest form of noise reduction is a good set of ANR headsets. You'll NEVER get the noise level as low (with fabric and foam) as a good set of headsets will get it. For $400, you can get a Lightspeed ANR set which worked great for me in the back seat of Lee Devlin's L.E.< I agree with Marc. I purchased the "modify your headset" ANR electronics ($169) for my DC. Very cheap fix. Works well and considerably reduced my cabin noise. I upgraded my modified headset for a production headset to get better stereo music quality. Sounds great with an ANR system. I never have understood why our planes are soooooo much louder than a Spam Can. I would think with the engine in the back and all that nice foam we would be at least as quiet. I think it may be the reflection of the exhaust noise off the prop. I have often wondered about the effects of moving the exhaust outlets to the bottom of the cowl, and more forward of the prop. A properly designed exhaust (2 into 1) of the proper length, should develop more power, and would allow the exit to be in a different position. From: wilhelmson@scra.org Date: Tue, 2 Dec 1997 16:05:42 -0500 Subject: Re: COZY: Noise reduction A cozy is much quieter than a cessna when flying at the same airspeed. The noise in the cessna is prop wash over the windshield, metal vibration noise, and exhaust noise. The noise in the cozy is almost all wind noise, therefore flying at cessna speeds (120 mph max) reduces the noise level to way below the noise level of wide open cessna noise. The noise in the cozy is higher frequency so if you have young ears you really notice it. If you have old ears that have already been ruined by the scream of military jet engines 20 years ago (like mine) it doesn't bother as much. The solution is a high quality good fitting headset. I use a clark with oil filled ear cushions. Date: Wed, 3 Dec 1997 11:37:27 -0700 From: Stefan G Siegel Subject: Re: COZY: Noise reduction I am flying a Long Eze and just switched props from the Prince prop with the fancy bent tips that was on there since I bought this airplane, to a regular tipped prop. Performance in terms of climb and cruise is the same, but the cabin noise level in the high frequency range went _way_ up. I am not affiliated with Prince by any means, but I sure like their props. --------------------------------------------------------------- Stefan Siegel AME Hydrodynamics Lab University of Arizona Dep. of Aerospace and Mech Eng Tucson, AZ 85721 email to: stefan@u.arizona.edu Phone: (520) 621-9106 --------------------------------------------------------------- From: Marc J. Zeitlin Subject: RE: COZY: Noise reduction (fwd) Date: Wed, 3 Dec 97 17:53:03 EST Guy Terren writes; >Can some one give me an address for the following device? . >I couldn' read the E-Mail sender. >I agree with Marc. I purchased the "modify your headset" ANR electronics >($169) for my DC. This is a headset modification from: Headsets Inc, 2330-B Lakeview, Amarillo, TX, 79109 (806) 373-9515 or: (806) 358-6336 This is the last known address I could find. It installs into an existing passive headset. -- Marc J. Zeitlin Email: marcz@an.hp.com by post.larc.nasa.gov (8.8.6.1/pohub4.2) with SMTP id HAA03650 for ; Thu, 4 Dec 1997 07:45:23 -0500 (EST) Date: Thu, 04 Dec 1997 07:37:48 -0500 From: Paul Krasa Subject: RE: COZY: Noise reduction (fwd) Let me second, third or what ever. I have enjoyed using my headset with the ANR conversion. Any homebuilder can do the conversion. It is quick and simple; toke about an hour and a half for the first headset and about an hour for the second. Love that learning curve. Paul Krasa Long EZ 214LP From: cdenk@ix.netcom.com Date: Sun, 7 Dec 1997 18:02:33 -0600 (CST) Subject: RE: COZY: Noise reduction (fwd) For what is worth: About a year ago I installed the ANR kits in my Mooney friend's headsets, a week later, I removed them, and he got his money back. He was intending to be a distributor for them. I have the BOSE, they are expensive, the new models are more comfortable, will upgrade some day. Just finished flying 3.8 hours Atlanta to Cleveland, got out and talked in normal volume levels.