X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sat, 31 Dec 2005 17:02:25 -0500 Message-ID: X-Original-Return-Path: Received: from wind.imbris.com ([216.18.130.7] verified) by logan.com (CommuniGate Pro SMTP 5.0.5) with ESMTPS id 907408 for lml@lancaironline.net; Sat, 31 Dec 2005 15:26:37 -0500 Received-SPF: none receiver=logan.com; client-ip=216.18.130.7; envelope-from=brent@regandesigns.com Received: from [192.168.1.100] (vsat-148-63-101-227.c002.t7.mrt.starband.net [148.63.101.227]) (authenticated bits=0) by wind.imbris.com (8.12.11/8.12.11.S) with ESMTP id jBVKPdAS063407 for ; Sat, 31 Dec 2005 12:25:43 -0800 (PST) (envelope-from brent@regandesigns.com) X-Original-Message-ID: <43B6E93A.7080902@regandesigns.com> X-Original-Date: Sat, 31 Dec 2005 12:25:30 -0800 From: Brent Regan User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.2) Gecko/20040804 Netscape/7.2 (ax) X-Accept-Language: en-us, en MIME-Version: 1.0 X-Original-To: Lancair Subject: Re: D-Subs Content-Type: multipart/alternative; boundary="------------000802050802090304000107" This is a multi-part message in MIME format. --------------000802050802090304000107 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit From Paul Lipps in response to my generally disparaging remarks regarding D-Sub connectors: "Litton Industries and Hughes had D-Sub connectors on their approved list for spacecraft. 'Course, gold only, not tinned!" Silly me, I was referring to the 99.99% of the formed contact, tin plated, screw retained, plastic back shelled (POS) D-Subs that give the rest a bad name. By the time you pay the ~$150 for a flight qualified, mill spec D-Sub you could have a sealed circular metal shell connector isn't prone to "scooping" pins during mate and doesn't require three hands, a screwdriver and a flashlight to mate / de-mate. D-Subs are popular because they are ubiquitous and cheap, not because they make a good choice for flight critical electrical connections. Of course, if you want to use them on your in-flight passenger entertainment system or other secondary use, go ahead. Just be mindful that TWA Flight 800 exploded in midair and crashed into the Atlantic because of, in part, poor wiring practices. The best, lightest, most reliable and cheapest connector is no connector at all. For a penny in solder and a dime in heat shrink you can have a waterproof, vibration proof, lightweight connection that is ideally suited for empennage trim motors, fans, gear door switches and other harsh environment applications. Yes you will need a soldering iron to remove the trim motor or switch but so what? How often are you planning to do that? Compare that effort to buying, terminating, strain relieving, installing, maintaining and carrying around a connector (and counterweight lead) and it starts looking pretty easy. In situations where you need a connector IMHO the best value is in the AMP Circular Plastic Connectors (CPC) provided you use the machined and gold plated contacts (not the formed ones). They are also available in metal shells for firewall forward applications. www.digikey.com is a good source. Treat every decision about how you build your airplane as if your life depended on it because your life will depend on some of them. The problem is that you may not know in advance which ones it will be. Regards Brent Regan --------------000802050802090304000107 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit From Paul Lipps in response to my generally disparaging remarks regarding D-Sub connectors:

"Litton Industries and Hughes had D-Sub connectors on their approved list for spacecraft. 'Course, gold only, not tinned!"

Silly me, I was referring to the 99.99% of the formed contact, tin plated, screw retained, plastic back shelled (POS) D-Subs that give the rest a bad name.

By the time you pay the ~$150 for a flight qualified, mill spec D-Sub you could have a  sealed circular metal shell connector isn't prone to "scooping" pins during mate and doesn't require three hands, a screwdriver and a flashlight to mate / de-mate.

D-Subs are popular because they are ubiquitous and cheap, not because they make a good choice for flight critical electrical connections. Of course, if you want to use them on your in-flight passenger entertainment system or other secondary use, go ahead. Just be mindful that TWA Flight 800 exploded in midair and crashed into the Atlantic because of, in part, poor wiring practices.

The best, lightest, most reliable and cheapest connector is no connector at all.  For a penny in solder and a dime in heat shrink you can have a waterproof, vibration proof, lightweight connection that is ideally suited for empennage trim motors, fans, gear door switches and other harsh environment applications. Yes you will need a soldering iron to remove the trim motor or switch but so what? How often are you planning to do that? Compare that effort to buying,  terminating, strain relieving, installing,  maintaining and carrying around a connector (and counterweight lead) and it starts looking pretty easy.

In situations where you need a connector IMHO the best value is in the AMP Circular Plastic Connectors (CPC) provided you use the machined and gold plated contacts (not the formed ones).  They are also available in metal shells for firewall forward applications.  www.digikey.com is a good source.

Treat every decision about how you build your airplane as if your life depended on it because your life will depend on some of them. The problem is that you may not know in advance which ones it will be.

Regards
Brent Regan
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