X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 26 Jul 2012 12:31:16 -0400 Message-ID: X-Original-Return-Path: Received: from imr-ma06.mx.aol.com ([64.12.78.142] verified) by logan.com (CommuniGate Pro SMTP 6.0c1) with ESMTP id 5679255 for lml@lancaironline.net; Thu, 26 Jul 2012 12:19:19 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.78.142; envelope-from=Sky2high@aol.com Received: from mtaomg-da03.r1000.mx.aol.com (mtaomg-da03.r1000.mx.aol.com [172.29.51.139]) by imr-ma06.mx.aol.com (8.14.1/8.14.1) with ESMTP id q6QGIeNO010983 for ; Thu, 26 Jul 2012 12:18:40 -0400 Received: from core-mtb002a.r1000.mail.aol.com (core-mtb002.r1000.mail.aol.com [172.29.234.197]) by mtaomg-da03.r1000.mx.aol.com (OMAG/Core Interface) with ESMTP id E5017E000087 for ; Thu, 26 Jul 2012 12:18:39 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: <2c9f8.1ddf45e1.3d42c7df@aol.com> X-Original-Date: Thu, 26 Jul 2012 12:18:39 -0400 (EDT) Subject: Re: [LML] Re: LNC2 Gear relays X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_2c9f8.1ddf45e1.3d42c7df_boundary" X-Mailer: AOL 9.6 sub 168 X-Originating-IP: [67.175.156.123] x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:390846624:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d338b50116ddf5839 --part1_2c9f8.1ddf45e1.3d42c7df_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Angier, Sometimes solenoid type relay placement is over thought. Consider that aircraft are in a state of continuous vibration and subject to + G's in turbulence. The Master (continuous relay, weaker pull in) is positioned upright to utilize the weight of the contact to remain or return to the "on" state under certain flight conditions. The pump relays (intermittent, stronger pull in) may be placed upside down so that the same forces might assist in opening the contacts in case the relay is "sluggish." Now, if you ask about the starter relay ..... The most frequent cause of intermittent relay failure is from holding it "in" too long causing overheating, coil wire coatings to melt or otherwise fail. In wee Lancairs this happens because the standard wiring diagram separately "fuses" the pump power and the relay coil power. If one has the master on and pulls the pump breaker while a pressure switch can activate a selected relay (lo pressure, up or down sw position), it will eventually fail without any panel indication (transit light is powered by pump power). One solution is to fuse the relays after the pump breaker so that pulling the pump breaker removes all electricity from the gear system. In building, as in life, it's your choice. Grayhawk Consider why it is aviation practice to put bolt heads forward................. In a message dated 7/26/2012 10:22:22 A.M. Central Daylight Time, N4ZQ@VERIZON.NET writes: Figure 14-4 in the install manual shows the hydraulic powerpack, relays, etc. on the back of the baggage bulkhead. In this figure, the gear relays are shown positioned 'up side down' as compared to the master relay. But nowhere in the install manual is there any discussion about how to position these relays...right side up, up side down, etc...., or WHY. Apparently there is a history of these relays failing and I'm wondering if it's best to just swap them out for solid state relays. Angier Ames N4ZQ -- For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html --part1_2c9f8.1ddf45e1.3d42c7df_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

Angier,

Sometimes solenoid type relay placement is over thought. = =20 Consider that aircraft are in a state of continuous vibratio= n and=20 subject to + G's in turbulence. The Master (continuous relay, we= aker=20 pull in) is positioned upright to utilize the weight of the contact to= =20 remain or return to the "on" state under certain= =20 flight conditions. The pump relays (intermittent, stronger pull = in)=20 may be placed upside down so that the same forces might assist in opening t= he=20 contacts in case the relay is "sluggish." Now, if you ask about the= =20 starter relay .....

The most frequent cause of intermittent relay failure is from=20 holding it "in" too long causing overheating, coil wire coatings to me= lt or=20 otherwise fail. In wee Lancairs this happens because the=20 standard wiring diagram separately "fuses" the pump power and the relay coi= l=20 power. If one has the master on and pulls the pump breaker while = ;a=20 pressure switch can activate a selected relay (lo pressure, up or down sw= =20 position), it will eventually fail without any panel indication (transit li= ght=20 is powered by pump power). One solution is to fuse the relays after t= he=20 pump breaker so that pulling the pump breaker removes all electricity from = the=20 gear system.

In building, as in life, it's your choice.

Grayhawk

Consider why it is aviation practice to put bolt heads=20 forward.................

In a message dated 7/26/2012 10:22:22 A.M. Central Daylight Time,=20 N4ZQ@VERIZON.NET writes:

= Figure=20 14-4 in the install manual shows the hydraulic powerpack, relays, etc. on= the=20 back of the baggage bulkhead.
In this figure, the gear relays are show= n=20 positioned 'up side down' as compared to the master relay. But nowhere in= the=20 install manual is there any discussion about how to position these=20 relays...right side up, up side down, etc...., or WHY.
Apparently ther= e is=20 a history of these relays failing and I'm wondering if it's best to just = swap=20 them out for solid state relays.

Angier Ames
N4ZQ
--
For= =20 archives and unsub=20 http://mail.lancaironline.net:81/lists/lml/List.html --part1_2c9f8.1ddf45e1.3d42c7df_boundary--