X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 18 Jan 2006 01:23:44 -0500 Message-ID: X-Original-Return-Path: Received: from mail.pshift.com ([63.166.217.30] verified) by logan.com (CommuniGate Pro SMTP 5.0.6) with ESMTP id 929820 for lml@lancaironline.net; Tue, 17 Jan 2006 10:26:25 -0500 Received-SPF: none receiver=logan.com; client-ip=63.166.217.30; envelope-from=colyncase@earthlink.net Received: from ccaselt (unverified [216.57.118.156]) by mail.pshift.com (Vircom SMTPRS 4.2.425.24) with SMTP id for ; Tue, 17 Jan 2006 10:25:40 -0500 Received-SPF: none (mail.pshift.com: domain of colyncase@earthlink.net does not designate any permitted senders) X-Modus-ReverseDNS: Error=0x0000232A X-Modus-BlackList: 216.57.118.156=OK;colyncase@earthlink.net=OK X-Modus-RBL: 216.57.118.156=OK X-Modus-Trusted: 216.57.118.156=NO X-Original-Message-ID: <1e7601c61b7a$447a1790$c611020a@nvidia.com> From: "colyncase on earthlink" X-Original-To: "Lancair Mailing List" References: Subject: Re: [LML] LIVP stormscope problems X-Original-Date: Tue, 17 Jan 2006 07:25:36 -0800 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_1E71_01C61B37.35F68F20" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_1E71_01C61B37.35F68F20 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Stan said, Has anyone gotten a stormscope to work properly in a lancair? We are = just now flying and the wx 500 sold to me and installed by lancair = avionics is not cutting it. Any suggestions or lessons learned? Thx. = Stan. Stan, I have this task still ahead of me but I have inquired. My belief is: -yes it has been made to work. -The location believed to work is far back on the under side of the = fuselage. -an alternate suggested location is at the wingtip (although seems = incompatible with strobes) -if you don't skin map and place accordingly, it won't work. every = plane is different - ground planes are an issue. I include a post from Bob Simon from = June 2005 Colyn Bob Simon's post Several different techniques are being used on composite aircraft to = produce the antenna ground plane required by a 'spherics (Stormscope) = and a TCAS-type traffic alert. I started an investigation into the use = of a metallized graphite scrim that could be easily applied. At this = point that application is questionable because the Ryan TAS operating = frequency is 1 GHz and the wavelength is so short that the open spaces = in the scrim might become re-transmitting antennae. Jury's still out on = that one. However the engineers at Ryan like Bob Schofield have been = helpful beyond measure, and here is what I have gleaned from them so = far: =20 The ground plane must be VERY conductive. The resistance from center = antenna attach point to aircraft ground must be less than 10 milliOhm - = 0.01 Ohm. Don't try to measure that with the VOM that you bought at = NAPA. The plane must be symmetrical along 2 axis fore-aft and = port-starbord. Curved to match the fuselage shape is OK. =20 A ground plane of solid metal foil seems to work best. Conductive = paints based on Ni or Ag plated copper will NOT work over time. Tests = on composite helicopters have shown that the painted plane is effective = initially but after one year begins to degrade. The engineers theorize = that the paint becomes brittle with age and begins to crack. That = leaves slots that re-transmit and isolated islands that are not = grounded. The situation would be worse with a pressurized aircraft = where the skin walls flex out and back with every flight, so a definite = no-no for the Lancair IV-P and ES-P. =20 One material recommended is a thin Al foil available from McMaster-Carr, = p/n 9060K16. It is dead soft, 0.005" thick, and comes in rolls 36" wide = by 100 feet long. The full rolls cost $145 - hopefully your avionics = shop will sell you smaller quantities. Typical installations require = two pieces about 3 ft by 3 ft each. The material is soft enough to = conform to curves and bumps on the cabin deck and overhead, and could be = adhered with a contact spray like 3M 7700. The ground plane must be = connected to the aircraft ground with at least two 12 to 14 ga. wires - = do not rely on the coax cable shield to ground the plane. The external antenna should be mounted over a thin Al sheet cut the = exact same footprint as the antenna. That sheet should be affixed to = the fuselage with two 6/32 countersunk machine screws that go through = the Al sheet, then the fuselage and then the internal Al ground plane = where the screws are fastened with two self-locking nuts. The external = antenna is then attached with its six screws to the fuselage, trapping = the Al plate beneath, and the external sandwich edge is sealed with RTV. = =20 The coax cable to use is 50 Ohm RG-400 cut 16 feet long. Not about "15 = feet" - cut it 16 feet long. The extra could be looped into a large = coil at least 2 feet in diameter. You will need 4 of the leads, they = each must be 16 feet long, and they should measure 2.5 dB to 3.5dB at 1 = GHz. =20 More details when and if I get 'em. =20 Robert M. Simon, GlaStar N161GS and Lancair ES-P(xl) N301ES.=20 ------=_NextPart_000_1E71_01C61B37.35F68F20 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Stan said,

Has anyone gotten a = stormscope to=20 work properly in a lancair? We are just now flying and the wx 500 sold = to me and=20 installed by lancair avionics is not cutting it. Any suggestions or = lessons=20 learned? Thx. Stan.

 

Stan,

    I have = this task=20 still ahead of me but I have inquired.

    My = belief is:=20 -yes it has been made to work.

    -The = location=20 believed to work is far back on the under side of the=20 fuselage.

    -an = alternate=20 suggested location is at the wingtip (although seems incompatible with=20 strobes)

    -if you = don't=20 skin map and place accordingly, it won't work.  every plane is=20 different

    - = ground planes=20 are an issue.   I include a post from Bob Simon from June=20 2005

 

 

Colyn

 

Bob Simon's = post

 


Several different techniques are being used on composite = aircraft to=20 produce the antenna ground plane required by a 'spherics (Stormscope) = and a=20 TCAS-type traffic alert.  I started an investigation into the use = of a=20 metallized graphite scrim that could be easily applied.  At this = point that=20 application is questionable because the Ryan TAS operating frequency is = 1 GHz=20 and the wavelength is so short that the open spaces in the scrim might = become=20 re-transmitting antennae.  Jury's still out on that = one.  =20 However the engineers at Ryan like Bob Schofield have been helpful = beyond=20 measure, and here is what I have gleaned from them so far:  =


The=20 ground plane must be VERY conductive.  The resistance from center = antenna=20 attach point to aircraft ground must be less than 10 milliOhm - 0.01 = Ohm. =20 Don't try to measure that with the VOM that you bought at NAPA.  = The plane=20 must be symmetrical along 2 axis fore-aft and port-starbord.  = Curved to=20 match the fuselage shape is OK. 


A ground plane of = solid metal=20 foil seems to work best.  Conductive paints based on Ni or Ag = plated copper=20 will NOT work over time.  Tests on composite helicopters have shown = that=20 the painted plane is effective initially but after one year begins to=20 degrade.  The engineers theorize that the paint becomes brittle = with age=20 and begins to crack.  That leaves slots that re-transmit and = isolated=20 islands that are not grounded.  The situation would be worse with a = pressurized aircraft where the skin walls flex out and back with every = flight,=20 so a definite no-no for the Lancair IV-P and ES-P. 


One = material recommended is a thin Al foil available from McMaster-Carr, p/n = 9060K16.  It is dead soft, 0.005" thick, and comes in rolls 36" = wide by 100=20 feet long.  The full rolls cost $145 - hopefully your avionics shop = will=20 sell you smaller quantities.  Typical installations require two = pieces=20 about 3 ft by 3 ft each.  The material is soft enough to conform to = curves=20 and bumps on the cabin deck and overhead, and could be adhered with a = contact=20 spray like 3M 7700.  The ground plane must be connected to the = aircraft=20 ground with at least two 12 to 14 ga. wires - do not rely on the coax = cable=20 shield to ground the plane.


The external antenna should be = mounted=20 over a thin Al sheet cut the exact same footprint as the antenna.  = That=20 sheet should be affixed to the fuselage with two 6/32 countersunk = machine screws=20 that go through the Al sheet, then the fuselage and then the internal Al = ground=20 plane where the screws are fastened with two self-locking nuts.  = The=20 external antenna is then attached with its six screws to the fuselage, = trapping=20 the Al plate beneath, and the external sandwich edge is sealed with = RTV. =20


The coax cable to use is 50 Ohm RG-400 cut 16 feet = long.  Not=20 about "15 feet" - cut it 16 feet long.  The extra could be looped = into a=20 large coil at least 2 feet in diameter.  You will need 4 of the = leads, they=20 each must be 16 feet long, and they should measure 2.5 dB to 3.5dB at 1=20 GHz. 


More details when and if I get 'em. =20


Robert M. Simon,  GlaStar N161GS and Lancair ES-P(xl)=20 N301ES. 

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