X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from EXHUB003-4.exch003intermedia.net ([207.5.74.111] verified) by logan.com (CommuniGate Pro SMTP 5.2.14) with ESMTPS id 3636215 for flyrotary@lancaironline.net; Fri, 08 May 2009 12:49:06 -0400 Received-SPF: none receiver=logan.com; client-ip=207.5.74.111; envelope-from=jwhaley@datacast.com Received: from EXVMBX003-5.exch003intermedia.net ([207.5.74.45]) by EXHUB003-4.exch003intermedia.net ([207.5.74.111]) with mapi; Fri, 8 May 2009 09:48:31 -0700 From: Jeff Whaley To: Rotary motors in aircraft Date: Fri, 8 May 2009 09:48:30 -0700 Subject: RE: [FlyRotary] Re: John Downings Tach Thread-Topic: [FlyRotary] Re: John Downings Tach Thread-Index: AcnP+UI4scxKm+YhRrqrxDKG07I77QAAFu6Q 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 Hi Bob, the unit has 2 pick-ups, so with a 4/4 you need both coil pick-ups = to get 2 pulses per rev, same as with the 2/2; if you had a 1 cylinder/2 st= roke it would give 1 pulse per rev; therefore the number of cylinders matte= r. With the V6, 2 pick-ups also produce 2 pulses per rev, but since they ar= e occurring a slightly slower rates the frequency to voltage conversion was= not accurate; I changed the R/C filter on the input and adjusted the inter= nal reference pot to increase the rpm readout ... drove around for a few we= eks with it in my Sonoma to verify calibration with Sonoma Tach. The rpm ma= x reading is 9999. Jeff -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Beh= alf Of Bob White Sent: Friday, May 08, 2009 12:18 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: John Downings Tach Hi Jeff, Thanks for the tip. There is something I don't understand about the specs for this unit. It's good for 4 cylinder 4 stroke or 2 cylinder 2 stroke. If I use the spark plug wire for the pickup, a 4 stroke (piston) engine will see one spark per two rev. Why does it matter how many pistons there are? If it's a wasted spark system, then one spark per rev. just like a two stroke piston engine. There must be something basic I don't understand. What sort of mod did it need for the V6? BTW, what is the maximum rpm reading for that unit? Thanks, Bob W. On Fri, 8 May 2009 07:48:47 -0700 Jeff Whaley wrote: > I like the belt and suspenders!! > I am using a UMA digital tachometer 2 1/4" from Aircraft Spruce that was = originally designed for 4 cylinder engines using an electrical impulse pick= up from spark plug leads. I modified it to mate with the Ford V6; I have mo= dified it again to connect to the EC2 driving the R1 PRI injector. The rota= ry firing system is similar to a 4 cylinder so if this tach is still availa= ble (Part # 10-24885) it would work off spark plug impulse couplers. > Jeff >=20 > -----Original Message----- > From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On B= ehalf Of Bob White > Sent: Friday, May 08, 2009 12:14 AM > To: Rotary motors in aircraft > Subject: [FlyRotary] John Downings Tach >=20 > John is using a standard tach that is normally connected to a distributor= /coil ignition system. The straight 12V pulse used for the > LS1 coils wouldn't activate it. I built an interface for him that involv= ed taking that pulse as an input and generating a shorter constant pulse wi= dth output. I modified the tach to trigger on the lower voltage signal, an= d adjusted the scale factor to read correctly with one pulse/rev. As John = reported, it worked for about 0.8 hours, then quit. He is sending everythi= ng back to me so that I can find out where the problem is. I would like to= find a tach solution that John can use without modifying anything. The pa= rameters are he has a 2 1/16 inch mounting hole, the tach needs to read cor= rectly with 1 pulse/rev (would be the same as a two cylinder piston engine = with coil and distributor), should trigger directly on a 12V pulse. >=20 > I've found tachs on the web that mention working with distributorless or = electronic systems, but none of them were the 2 1/16 inch type. I found a = converter, the MSD 8913, but on the Summit Racing catalog it specifically s= ays it won't work with the LS-1 system. It work by sensing the current pul= ses to the 12V power lead on the coil. I don't know why it wouldn't work w= ith an LS-1 coil, but it doesn't seem like a good investment when the LS-1 = is specifically mentioned as not working. >=20 > Can anyone recommend a tach solution that John can use with his LS-1 Coil= rotary engine combination? >=20 > On another topic, John has the only system I've heard of that has the cap= ability to run on either EFI or a carburettor. John posted a picture of hi= s Tailwind a few days ago. It's a very good picture but considering the re= dundancy of the EFI/carb system, I felt that the picture was lacking. I su= bmit this edited version as being more indicative of John's desire for unco= mpromised safety. >=20 > Bob W. >=20 > -- > 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/ >=20 > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/Lis= t.html --=20 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/ -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.= html