X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from EXHUB003-2.exch003intermedia.net ([207.5.74.29] verified) by logan.com (CommuniGate Pro SMTP 5.2.14) with ESMTPS id 3636096 for flyrotary@lancaironline.net; Fri, 08 May 2009 10:49:25 -0400 Received-SPF: none receiver=logan.com; client-ip=207.5.74.29; envelope-from=jwhaley@datacast.com Received: from EXVMBX003-5.exch003intermedia.net ([207.5.74.45]) by EXHUB003-2.exch003intermedia.net ([207.5.74.29]) with mapi; Fri, 8 May 2009 07:48:03 -0700 From: Jeff Whaley To: Rotary motors in aircraft Date: Fri, 8 May 2009 07:48:47 -0700 Subject: RE: [FlyRotary] John Downings Tach Thread-Topic: [FlyRotary] John Downings Tach Thread-Index: AcnPk3c2BAyilAy7RB+NE5I1apAZgwAVyFNA Message-ID: References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 I like the belt and suspenders!! I am using a UMA digital tachometer 2 1/4" from Aircraft Spruce that was or= iginally designed for 4 cylinder engines using an electrical impulse pickup= from spark plug leads. I modified it to mate with the Ford V6; I have modi= fied it again to connect to the EC2 driving the R1 PRI injector. The rotary= firing system is similar to a 4 cylinder so if this tach is still availabl= e (Part # 10-24885) it would work off spark plug impulse couplers. Jeff -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Beh= alf Of Bob White Sent: Friday, May 08, 2009 12:14 AM To: Rotary motors in aircraft Subject: [FlyRotary] John Downings Tach John is using a standard tach that is normally connected to a distributor/c= oil ignition system. The straight 12V pulse used for the LS1 coils wouldn't activate it. I built an interface for him that involved= taking that pulse as an input and generating a shorter constant pulse widt= h output. I modified the tach to trigger on the lower voltage signal, and = adjusted the scale factor to read correctly with one pulse/rev. As John re= ported, it worked for about 0.8 hours, then quit. He is sending everything= back to me so that I can find out where the problem is. I would like to f= ind a tach solution that John can use without modifying anything. The para= meters are he has a 2 1/16 inch mounting hole, the tach needs to read corre= ctly with 1 pulse/rev (would be the same as a two cylinder piston engine wi= th coil and distributor), should trigger directly on a 12V pulse. I've found tachs on the web that mention working with distributorless or el= ectronic systems, but none of them were the 2 1/16 inch type. I found a co= nverter, the MSD 8913, but on the Summit Racing catalog it specifically say= s it won't work with the LS-1 system. It work by sensing the current pulse= s to the 12V power lead on the coil. I don't know why it wouldn't work wit= h an LS-1 coil, but it doesn't seem like a good investment when the LS-1 is= specifically mentioned as not working. Can anyone recommend a tach solution that John can use with his LS-1 Coil r= otary engine combination? On another topic, John has the only system I've heard of that has the capab= ility to run on either EFI or a carburettor. John posted a picture of his = Tailwind a few days ago. It's a very good picture but considering the redu= ndancy of the EFI/carb system, I felt that the picture was lacking. I subm= it this edited version as being more indicative of John's desire for uncomp= romised safety. Bob W. -- N93BD - Rotary Powered BD-4 - http://www.bob-white.com 3.8 Hours Total Time and holding Cables for your rotary installation - http://roblinstores.com/