---------------------------------------------------------- RV6-List Digest Archive --- Total Messages Posted Thu 12/12/02: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:35 AM - Status... (Matt Dralle) 2. 04:13 AM - Re: sound proofing (Boyd C. Braem) 3. 05:54 AM - Re: sound proofing (Mark Phillips) 4. 02:55 PM - Re: sound proofing (Boyd C. Braem) ________________________________ Message 1 _____________________________________ Time: 01:35:21 AM PST US From: Matt Dralle Subject: RV6-List: Status... --> RV6-List message posted by: Matt Dralle Dear Listers, As promised, here's an update on this year's List Support Gift shipping status! Wednesday 12/11 all of the CDROM-Only and all but 12 of the CDROM+Flight Bag Gifts were shipped out via US Parcel Post. Maximum delivery will be 8 days to the most remote areas. For those receiving a CDROM+Flight Bag, note that the CDROM is tucked inside one of the pouches in the Flight Bag so don't miss it!! The remaining Flight-Bag+CDROM, Flight Bag-Only and A&P Book Sets will go out as soon as the next shipments arrive, hopefully in the next few days. Once again, I want to thank everyone that made a Contribution to this year's Email List Fund Raiser! The email and web systems are now running on brand new APC 2.2kva UPS systems thanks to the support of List members this year. Additionally, the Email System will be upgraded later this month with a new, Dual Processor 2.8Ghz Linux system due to arrive any day! Your generosity has made these upgrades possible and nothing else! Thank you so much! Best regards, Matt Dralle Email List Contribution Web Site: http://www.matronics.com/contribution Matt G Dralle | Matronics | PO Box 347 | Livermore | CA | 94551 925-606-1001 V | 925-606-6281 F | dralle@matronics.com Email http://www.matronics.com/ WWW | Featuring Products For Aircraft DNA: do not archive ________________________________ Message 2 _____________________________________ Time: 04:13:28 AM PST US From: "Boyd C. Braem" Subject: Re: RV6-List: sound proofing --> RV6-List message posted by: "Boyd C. Braem" Tom-- We did some tinkering with fuselage sound insulation some years back and found that in a RV-6 with a fitted cowl, insulating the firewall made no appreciable (subjective) noise difference for the two major offenders: prop noise and exhaust noise. The best was insulating the cockpit floor. The baggage floor also made a slight difference. Even light carpeting on the cockpit side-walls helped a little. But, not the firewall. The most noise reductiion came from insulating the canopy--tho there is a major drawback to this. Boyd. do not archive Tom and Marilyn Law wrote: > --> RV6-List message posted by: "Tom and Marilyn Law" > > I am to a point where need to think of soundproofing my RV6-A before I > can no longer see the firewall and would not want to add to much weight > .....or expense. Any ideas welcome. Tom Law...... instrument sub-panel > tlaw@klondiker.com ________________________________ Message 3 _____________________________________ Time: 05:54:31 AM PST US From: Mark Phillips Subject: Re: RV6-List: sound proofing --> RV6-List message posted by: Mark Phillips Hi Boyd- Working on the same stuff right now and curious if you saw reduced heat in the cockpit by insulating the firewall? What material did you try? Thanks from The PossumWorks in TN Mark "Boyd C. Braem" wrote: > --> RV6-List message posted by: "Boyd C. Braem" > > Tom-- > > We did some tinkering with fuselage sound insulation some years back and found > that in a RV-6 with a fitted cowl, insulating the firewall made no appreciable > (subjective) noise difference for the two major offenders: prop noise and > exhaust noise. The best was insulating the cockpit floor. The baggage floor > also made a slight difference. Even light carpeting on the cockpit side-walls > helped a little. But, not the firewall. The most noise reductiion came from > insulating the canopy--tho there is a major drawback to this. ________________________________ Message 4 _____________________________________ Time: 02:55:31 PM PST US From: "Boyd C. Braem" Subject: Re: RV6-List: sound proofing --> RV6-List message posted by: "Boyd C. Braem" Mark-- In the -6, if you have adequate cowl exhaust air flow, firewall heat does not seem to be a problem. The large area of the -6 firewall (compared to the -4/-8) transfers/dissipates the heat quite well. If you put your hand on the firewall it could be as hot as the top cowl, but your feet, 2-4" inches away (or more, if they're off the pedals), don't feel it. Some folks that position their exhaust pipes horizontal (to get that ephemeral "exhaust thrust effect" will have hot cockpit floor boards and others (ala Tracy Saylor), that trim the exhaust pipes so they don't protrude below the bottom cowl could have higher firewall temps and increased firewall exhaust noise. We tried a whole slew of different things (aviation/non-aviation grade) and the thing that correlated best with noise reduction was density (ie, weight)--you're not dampening internal sound waves (reflection), you're trying to prevent the intrusion of outside sound/vibration. So, dense, heavy stuff kills vibration transfer better than lighter stuff (of the same thickness). You have to decide where the trade-off is. As some listers have said, maybe the best answer is to go light on the insulation and use ANR headsets. I've converted my David-Clarks with that kit from Texas. I turn the ANR off when doing aerobatics so I can better hear the wind noise and engine/prop sound--tells me as much as the airspeed indicator--if you listen. Boyd. Super -6 Venice, FL Mark Phillips wrote: > --> RV6-List message posted by: Mark Phillips > > Hi Boyd- > > Working on the same stuff right now and curious if you saw reduced heat in the > cockpit by insulating the firewall? What material did you try? > > Thanks from The PossumWorks in TN > Mark > > "Boyd C. Braem" wrote: > > > --> RV6-List message posted by: "Boyd C. Braem" > > > > Tom-- > > > > We did some tinkering with fuselage sound insulation some years back and found > > that in a RV-6 with a fitted cowl, insulating the firewall made no appreciable > > (subjective) noise difference for the two major offenders: prop noise and > > exhaust noise. The best was insulating the cockpit floor. The baggage floor > > also made a slight difference. Even light carpeting on the cockpit side-walls > > helped a little. But, not the firewall. The most noise reductiion came from > > insulating the canopy--tho there is a major drawback to this.