Return-Path: Received: from smtp803.mail.sc5.yahoo.com ([66.163.168.182] verified) by logan.com (CommuniGate Pro SMTP 4.2b8) with SMTP id 320016 for flyrotary@lancaironline.net; Tue, 13 Jul 2004 14:09:50 -0400 Received-SPF: error receiver=logan.com; client-ip=66.163.168.182; envelope-from=dcarter@datarecall.net Received: from unknown (HELO Davidscmptr) (dcarter11@sbcglobal.net@64.219.119.224 with login) by smtp803.mail.sc5.yahoo.com with SMTP; 13 Jul 2004 18:09:17 -0000 Message-ID: <00ef01c46904$6fa841a0$6401a8c0@Davidscmptr> Reply-To: "David Carter" From: "David Carter" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Coil Harness (was: LS1 Coil Connector) Date: Tue, 13 Jul 2004 13:08:43 -0500 MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_NextPart_000_00EC_01C468DA.861B1EA0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1409 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1409 This is a multi-part message in MIME format. ------=_NextPart_000_00EC_01C468DA.861B1EA0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Dale, I saved his web page as an html document - no longer have the link. Just save the attachment and keep it for ref in lieu of getting it from the web site. I added another attachment - an e-mail that discusses 4 types of firewall penetrations and assessment of protection. If the attachment doesn't make it thru the FlyRotary e-mail server, here's the link: http://www.aeroelectric.com/articles.html and scroll down past the updates to Aeroelectric Connection to "How To Articles" and click the 2nd item, ". . . simple firewall penetrations for wires" I. Also, here's text from 2 Mar 2003 Q&A re the sealant around the wires in that "system": --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 07:37 PM 3/1/2003 -0600, you wrote: >--> AeroElectric-List message posted by: "David Carter" > > >Bob, > >Excellent pictures. What is the white "sheet" of material wrapped around >the wires in the engine compartment (coming out of the stainless steel >firewall fitting)? Is it "white fire sleeve" or something else? That is silicon rubber covered, fiberglas sleeving . . . similar to the stuff we sell in our fusible link kits. This is not a necessary component of the fire-stopping abilities of technique described. >Fire stop putty might have a tendancy to "migrate" out from under the clamp? Don't know why it would . . . >So, strips of fire sleeve material, as you showed, would be firmer and tend >to stay in place better - could put a small amount of fire putty inside >in/amongst the wires, under the wire sleeve "packing band". Do I have the >correct idea here? The putty has been used for a very long time in this an similar applications. I don't think I'd diddle with the technique without substantive testing or analysis as to what benefits it might offer. Bob . . ." [ end of 1st e-mail quote ] II. Dale, here's a 2nd Q&A, re sealing the stainless steel flange as it fits flush to the firewall: --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" 13 Mar 03: "At 11:17 AM 3/13/2003 -0800, you wrote: >--> AeroElectric-List message posted by: Julia > What's the best thing to use for sealant on the flanges which make up my >firewall wire penetration - i'm using SS tubing welded to a flange - so >what would go between the flange and the firewall - to make it >airtight? I"m not talking about around the wires - but just between the >flange and firewall? how about proseal - would that be ok -or should it >be some kind of fireproof silicone - I think someone mentinoed that >once, I cannot seem to find anything in aircraft spruce - can anyone >point me in the right direction for of where I might get the correct >product here? The installation I posted uses a fire-stop compound. Any stuff you can find at a builder's supply would probably be okay here. It's a thin, ideally zero-thickness interface and about any fire-resistant material is going to be hard to displace. I suspect silicone sealant would work okay there too. Bob . . ." [ end of 2nd e-mail quote ] III. Dale, here's text of a 3rd :"info" e-mail some "fire protection assessment" and good test data on "badness" of aluminum fittings in presence of fire "melts like wax in 10 seconds": " AeroElectric-List message 25 Feb 03 posted by: czechsix@juno.com "Guys, I saw this on Doug Reeves' website this morning and thought I'd post it here for those of you who aren't RV builders and probably didn't see it. Since the topic of how to protect wire bundles through the firewall while maintaining the integrity of the firewall has been discussed here before I thought it was relevant. You can see the text and pictures at: http://members6.clubphoto.com/doug412210/1161024/guest.phtml Here's the text for the archives: Firewall Penetrations Firewall Penetrations-by Vern Darley (vern@mindspring.com) Years ago,I was an Air Force Force pilot and had a jet engine throw a compressor blade thru the cockpit and hit the side of the ejection seat. The cockpit immediately filled with intense heat and I was solid IFR with dense white smoke inside the cockpit. In another type of AF plane,I once experienced an electrical fire in the cockpit. In college,I worked parting out crashed light aircraft at an FBO. Lately,I've wandered around aircraft junkyards scrounging parts. All of these experiences have made me accutely aware of how much I want to keep fire out of my RV cockpit. In the RV world,there are four main penetrations through our firewalls: engine controls,fuel lines, wiring, and cabin heat/air. Due to their small size and the availability of 'eyeballs',etc. engine controls are not a big threat to us. The fuel line penetration is normally handled by a through-the-firewall fitting. So, there remain two main threats to our health and safety: the wiring bundles and the cabin heat/air. Typically, most builders seem to opt for the rubber grommet and a dab of RTV for the wires,and depend on the aluminum cabin heat devices that Vans and others market to cover the two-inch-or-so firewall penetration for air. In my opinion, the aluminum devices are inadequate protection to keep fire on the engine side of my RV. In searching for solutions, I found a new company that has helped me solve these problems. I asked them for data,and Paul Bowmar, director of R&D provided me with a video of a recent test he conducted on aluminum vs.stainless firewall penetration devices. His company,EPM.AV Corporation, has developed a beautiful stainless version of the airbox most RVs need and has also manufactured various size wiring pass throughs.He has also tested various compounds that seal the wire bundles. In the tests, a standard aluminum RV style vent was subjected to a flame source at the 1600-1800 degree range that one would get in a fuel fire in a flying RV. The aluminum vent melted like wax within ten seconds! Even with a stainless flapper installed, this would not have protected us since the flapper would simply fall away when the supporting aluminum structure melted. Tests on an all stainless version of the same airbox endured extended direct flames with no damage for the duration of the test. Tests with wire penetrations yielded similar results and pointed out the need to use top grade wire and insulation for your through-the-firewall wiring. I've since bought actual products and am happy to report first class workmanship and to recommend their new products to my fellow RV'ers. Fly safe! Vern Darley 6A slowbuild Peachtree City, Ga" [ end of 3rd quoted e-mail ] - - - - - - - - - - - - - - - - - end of David's reply to Dale's original (next item below), to which this e-mail replies: ----- Original Message ----- From: "Dale Rogers" To: "Rotary motors in aircraft" Sent: Tuesday, July 13, 2004 9:41 AM Subject: [FlyRotary] Re: Coil Harness (was: LS1 Coil Connector) > ---------- Original message: > > > From: "David Carter" > > Date: 2004/07/12 Mon PM 10:59:19 EDT > > To: "Rotary motors in aircraft" > > Subject: [FlyRotary] Re: Coil Harness (was: LS1 Coil Connector) > > > > Dale, have you seen Bob Nuckoll's "towel bar" firewall fitting item on his > > web page? Very safe way to make firewall penetrations for your std wires. > > There's a commercial source for same that is reasonable (in the $50+ range > > vs $20-30 for roll-your-own parts) > > > > David > > David, > Is this a B&C Specialties Item? If so, it's very well camouflaged. It's going to take a while to search through Bob's site; do you - perchance - have a link to the page? > Dale > > > >> Homepage: http://www.flyrotary.com/ > >> Archive: http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_00EC_01C468DA.861B1EA0 Content-Type: text/html; name="Stainless tube + firesleeve and clamps.htm" Content-Transfer-Encoding: quoted-printable Content-Disposition: attachment; filename="Stainless tube + firesleeve and clamps.htm" AeroElectric Connection - Aircraft Firewall = Penetration

Bob's Shop Notes:
Getting the wires in while keeping the flames = out . .=20 .

The "firewall" on an airplane wasn't named with any = sense of=20 whimsy . . . 99.99% of the time, all it does is keep a blast of cold air = out of=20 the cockpit. But on rare occasions, it is expected to stand between a = fuel fed=20 fire and folks in the cockpit who are doing their best to survive the=20 experience.

Hundreds of thousands of single engine aircraft have been built in = the past=20 100 years. Most were fabricated with some attention paid to the physics = of fire=20 protection. Every firewall-sheet of stainless steel (or composite = material=20 selected for it's fire resistance) is perfectly capable of doing its job = . . .=20 as long as you don't cut holes in it. Unfortunately, it's necessary for = things=20 forward of the firewall to be in communication with things aft of the = firewall.=20 There are controls, fuel plumbing, instrumentation and power generation = wiring=20 that must run between engine compartment and cockpit thus requiring a = certain=20 number of HOLES in the firewall.

Penetrations of fuel and other fluid plumbing running through all = metal=20 bulkhead fittings require little further consideration. For certified = airplanes,=20 the FARs tell us that bulkhead feed through fittings of steel or = copper-alloy=20 may be used with no concerns for compromising firewall integrity. There = are a=20 variety of metal "eyeball" fittings available for easing the transition = of=20 throttle, prop, mixture and cowl flap controls at odd angles. This = leaves us=20 with the "soft" lines such as wires and perhaps small fluid lines for = pressure=20 instrumentation.

Click=20 here for larger image A visit with camera in hand to a = production line=20 for certified piston aircraft allowed me to record and share a = fabrication=20 technique for soft penetration. This technique has a long history = of=20 laboratory testing for effectiveness, production line convenience, = and=20 field maintainability. In this case, all of the wiring comes = through a=20 single, fairly large penetration fitting . . . but there's no = reason why=20 multiple, smaller fittings wouldn't work too . . .

Here we see how a stainless weldment bolted to the firewall = with steel=20 hardware provides the structural component of a transition for = wires and=20 other relatively "soft" materials running between cockpit and = engine=20 compartment. Note generous flange area outside the tube to flange=20 interface that is sealed with fire-stop when the flange is bolted = into=20 place.

Click=20 here for larger image The fittings for this airplane are made = from=20 0.050" stainless. Thickness and attaching geometry are a function = of how=20 much support the fitting needs to provide for the bundle of = transitioning=20 wires and tubes. The material shown here is pretty hefty stuff and = may=20 have been selected as handier to weld than thinner material. = Drawings for=20 other firewall fittings used in this same factory show materials = as thin=20 as 0.020" thick.

Builders can certainly experiment with thinner material and = alternative=20 joining techniques. Periodic inspections will show whether or not = there=20 are issues of mechanical robustness . . . not strong enough, = they'll=20 simply come apart. Given that fires are VERY rare, the failure of = an=20 experimental fitting doesn't represent a great threat as long as = you do=20 reasonably complete inspections during normal P/M activities . . . = like=20 every oil change. The worst thing that happens is that you have to = build a=20 more robust transition fitting and replace the broken one.

Click=20 here for larger image Looking up the business end of the = finished=20 transition. What's not visible in this view is the packing placed = around=20 wires so that the second hose clamp doesn't have to put a = super-crush on=20 the fire sleeve . . . . more on this later.

Click=20 here for larger image The flight-ready firewall penetration. A = second=20 hose clamp brings the fire sleeve down for a snug fit on the wire = bundle.=20 A filler wrap around a wire bundle much smaller than the i.d. of = the fire=20 sleeve makes for a better seal with less crush under the second = hose clamp=20 . . .=20

Click=20 here for larger image On another airplane, we find a similar = technique=20 except that the stainless steel firewall fitting is straight, no = 90-degree=20 bend. Otherwise, installation and functionality is same as shown = above.

Click=20 here for larger image This view illustrates an interesting = packing=20 material used to build up the wire bundle size. A piece of fire = sleeve was=20 cut down the side and made into a strip of wrapping filler. Note = that all=20 exposed edges of the fire sleeve are "doped" with the recommended = sealer=20 to preclude entry of moisture and to keep the edges from fraying . = . .

Questions or comments about this site? Click here to = contact Bob=20 at AeroElectric Connection

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