---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 03/22/11: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 08:25 AM - Bad Tach Readings - Grand Rapids EIS 4000 (Bob Falstad) 2. 08:54 AM - V-Speed ADS remote AoA indicator is back in production (Vern Little) ________________________________ Message 1 _____________________________________ Time: 08:25:16 AM PST US From: Bob Falstad Subject: AeroElectric-List: Bad Tach Readings - Grand Rapids EIS 4000 Hi, I have just started flying my GlaStar again after installing a Grand Rapids EIS 4000 and single screen Horizon HX. I've wired my traditional mag P-leads to tach input 1 (left mag) and tach input 2 (right mag). At first, the "left" mag and "both" positions showed normal, reasonable, stable RPM indications. During my runup at 1700 RPM, the "right" mag would fluctuate wildly between 3200 - 3400 RPM. After talking with Greg at GRT, I switched the inputs and the problem jumped over to the left mag. I then switched the inputs back and, again at Greg's suggestion, increased the resistor values on the right mag/input 2 to 47K Ohms and then to 100K Ohms. With the 100K Ohm resistor in place of the original 27K Ohm resistor, the problem abated somewhat. On runup, the right mag would show a believable RPM for a couple of seconds and then would fluctuate between 1200 - 1400 RPM. The pulse per revolution and mag sensitivity settings in the EIS are "1" and "low", respectively, for each mag. More recently, the left mag (and consequently, in the "both" mag position) is exhibiting the same wildly fluctuating behavior - to the point, the tach indications are useless. This occurs even though the engine is running at a constant RPM. An A&P/IA buddy of mine with extensive experience in light GA aircraft thought that maybe there was a bad ground in the P-leads so we put jumper wires from the magneto cases to the ground "forest-of-tabs". (The "hot mag" check was fine even before the jumper wires.) This damped out the RPM swings somewhat but did not eliminate the problem. (I'm using a conventional Start/Mag switch with the four shields (from each P-lead plus the shielded wire to each tach input) crimped on a common ring terminal attached to the ground lug on the switch. GRT's installation instructions say it isn't necessary to carry the shield all the way to the EIS box so I didn't.) Has anyone seen anything similar to this? Any thoughts whether it is in the wiring or in the EIS itself? Any troubleshooting steps that I can take to try to identify the root cause of the problem? Best regards Bob GlaStar N248BF ________________________________ Message 2 _____________________________________ Time: 08:54:57 AM PST US From: "Vern Little" Subject: AeroElectric-List: V-Speed ADS remote AoA indicator is back in production Several months ago, there was a discussion about our remote AoA indicator. It had been discontinued because it was costly to support and demand was low. Recent events, including the blossoming popularity of AoA, support of our device by multiple EFIS vendors and some good old arm twisting have resulted in the reintroduction of our device. The V-Speed ADS has more than 5 years flight experience in numerous aircraft, and is supported by both Dynon and GRT Avionics. MGL is also considering support. The V-Speed ADS is a glareshield mounted remote AoA indicator that interprets a serial air data stream to present a progressive bar graph type display in a 'heads-up' type location. It also presents cruise flight information at low AoA's, such as (programmable) Vfe, Va, Vno and Vne. If you don't have an AoA probe, it can be programmed for a slow flight display of Vx, Vref, Vso and Vs1 It has an internal light sensor that automatically dims for night operation. The device comes with a 5' tefzel shielded cable, SPDT switch (for in-cockpit programming access) and a snap bushing for routing the cable. The datasheet can be downloaded from the vx-aviation.com website. Availability: Devices are in stock. Price: See website for ordering $250 including shipping anywhere in the world. Thanks to the many customers who have shown support. Thanks, Vern Little Vx Aviation www.vx-aviation.com http://vx-aviation.com/documents/VSpeed_ADS.pdf ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.