---------------------------------------------------------- TeamGrumman-List Digest Archive --- Total Messages Posted Sun 08/08/04: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 10:42 AM - Engine analyzers (TeamGrumman@AOL.COM) 2. 03:43 PM - Re: Engine analyzers (Lee Verrone) 3. 11:08 PM - Battery Box Location (Steven Jackson) 4. 11:13 PM - Canopy Replacement (Steven Jackson) 5. 11:57 PM - Re: Battery Box Location (FLYaDIVE@AOL.COM) ________________________________ Message 1 _____________________________________ Time: 10:42:45 AM PST US From: TeamGrumman@AOL.COM Subject: TeamGrumman-List: Engine analyzers --> TeamGrumman-List message posted by: TeamGrumman@aol.com I installed the JPI 800 into my Tiger. It's the first engine analyzer that I've had in a plane I own. I've flown a lot of planes with the JPI (and a few odd analyzers) and I've installed about a dozen of them for customers. It's my experience that the CHT reads a bit (30+ degrees) higher with the JPI. But then, that is based on only flying similar planes with different analyzers and the results of installing a JPI 700 into a Comanche 250. On the Comanche, the owner reported that his temps were 50 degrees higher with the JPI. I completely re-did the baffles during the JPI installation including stripping and powder coating the metal baffles. I made sure there was nothing blocking the airflow through the engine. Still, the owner complained of higher than expected temps with the JPI. On my plane (Tiger, O360-A4K, new Lycoming cylinders, ported and polished), I've noticed that #3 CHT goes up faster than the others during climb, to the point that reducing power and staying full rich is required to keep temps below 450. EGTs remain fairly even between the cylinders; less than 50 degrees (quite often less than 30 degrees) variation between cylinders. In cruise, both CHT and EGT are even between the cylinders with CHTs staying in the low 400s or high 300s. On descent, I've also noticed that #3 is the first to activate the shock cooling feature on the JPI. So, it would seen that #3 is cooling well enough. Question: Has anyone else had experience with JPIs displaying higher temps than expected? Question: Has anyone noticed that different planes (different engine installations) have such dramatic differences in CHTs duing climb and cruise? Gary www.AuCountry.com ________________________________ Message 2 _____________________________________ Time: 03:43:29 PM PST US From: "Lee Verrone" Subject: RE: TeamGrumman-List: Engine analyzers --> TeamGrumman-List message posted by: "Lee Verrone" Gary, I also have the JPI 700 and I have the exact results that you explained below. One note I have the LoPresti nose bowl and I also had the baffling examined and filled any holes. I have heard that JPI is off by 30-50 deg but I have no facts to prove that. Would love to hear you outcome. Lee -----Original Message----- From: owner-teamgrumman-list-server@matronics.com [mailto:owner-teamgrumman-list-server@matronics.com] On Behalf Of TeamGrumman@AOL.COM Subject: TeamGrumman-List: Engine analyzers --> TeamGrumman-List message posted by: TeamGrumman@aol.com I installed the JPI 800 into my Tiger. It's the first engine analyzer that I've had in a plane I own. I've flown a lot of planes with the JPI (and a few odd analyzers) and I've installed about a dozen of them for customers. It's my experience that the CHT reads a bit (30+ degrees) higher with the JPI. But then, that is based on only flying similar planes with different analyzers and the results of installing a JPI 700 into a Comanche 250. On the Comanche, the owner reported that his temps were 50 degrees higher with the JPI. I completely re-did the baffles during the JPI installation including stripping and powder coating the metal baffles. I made sure there was nothing blocking the airflow through the engine. Still, the owner complained of higher than expected temps with the JPI. On my plane (Tiger, O360-A4K, new Lycoming cylinders, ported and polished), I've noticed that #3 CHT goes up faster than the others during climb, to the point that reducing power and staying full rich is required to keep temps below 450. EGTs remain fairly even between the cylinders; less than 50 degrees (quite often less than 30 degrees) variation between cylinders. In cruise, both CHT and EGT are even between the cylinders with CHTs staying in the low 400s or high 300s. On descent, I've also noticed that #3 is the first to activate the shock cooling feature on the JPI. So, it would seen that #3 is cooling well enough. Question: Has anyone else had experience with JPIs displaying higher temps than expected? Question: Has anyone noticed that different planes (different engine installations) have such dramatic differences in CHTs duing climb and cruise? Gary www.AuCountry.com advertising on the Matronics Forums. ________________________________ Message 3 _____________________________________ Time: 11:08:46 PM PST US From: "Steven Jackson" Subject: TeamGrumman-List: Battery Box Location --> TeamGrumman-List message posted by: "Steven Jackson" TG, With my nose now 8 pounds lighter thanks to Skytec, I've started looking at the battery box location with an eye on moving it from behind the baggage compartment, and back up to the firewall. Looking at the STC for my engine, it mentions either moving the battery aft, or adding ballast to the tail section. It does not however, mention anything about reinforcing the battery box for the increased weight of a G-35 battery vs. the old G-25. Since I've owned the plane, the battery has been in the aft position, so I don't know (other than the holes (filled) left in the firewall) how the old battery was positioned. Looking at my G-35, it looks like the battery will have to go in with its long axis perpendicular to the firewall, given the amount of space available. Is this how the original battery was positioned? I know the G-25 is a good bit smaller. My mechanic stated that the tradeoff is that the heat inside the engine compartment may decrease the battery life, but will aid servicing the battery and increase safety since there would be a shorter distance between the battery and master relay. I wouldn't mind a little more weight up front since I'm almost always skirting the aft CG limit with my aux fuel. Thanks, Steven Jackson '75 AA-1B Ser# 0534 (Collier STC) O-320A2B N1434R L22 Yucca Valley, CA ________________________________ Message 4 _____________________________________ Time: 11:13:08 PM PST US From: "Steven Jackson" Subject: TeamGrumman-List: Canopy Replacement --> TeamGrumman-List message posted by: "Steven Jackson" TG, I've seen enough emails to know that I need a Grumman pro to replace the windshield. My question is whether or not the canopy by itself is a more manageable project for me and my mechanic. I know there are some issues with fitting the tracks properly, but just from a glance, the rest of the disassembly/assembly looks fairly straightforward. The service manual makes it sound pretty germane, but I'm skeptical. Recommendations? Steven Jackson '75 AA-1B N1434R L22 Yucca Valley, CA ________________________________ Message 5 _____________________________________ Time: 11:57:32 PM PST US From: FLYaDIVE@AOL.COM Subject: Re: TeamGrumman-List: Battery Box Location --> TeamGrumman-List message posted by: FLYaDIVE@aol.com Steve: Sounds like you are exactly where you should be. Moving the CG Aft (within limits) is something that you should strive for. It makes the plane go faster and the controls lighter. Also since the Aux Fuel is a variable weight you may notice the controls and takeoff pitch to be lighter when Full and heavier when Empty and doing a landing. The Battery Aft will keep this variance to a lower value. I wish I could move my battery Aft. Another reason is you do not bake the hell out of it on hot days. Still another reason is less vibration breaking the battery construction down ... Vibration does not do good things for the stacking of the plates. As for the reinforcement of the battery box. Not needed on the BOX. But, I'm sure the bracketing is more than adequate if good construction procedures were followed AC 43-13. Barry "Chop'd Liver" ==========================Steve Wrote: TG, With my nose now 8 pounds lighter thanks to Skytec, I've started looking at the battery box location with an eye on moving it from behind the baggage compartment, and back up to the firewall. Looking at the STC for my engine, it mentions either moving the battery aft, or adding ballast to the tail section. It does not however, mention anything about reinforcing the battery box for the increased weight of a G-35 battery vs. the old G-25. Since I've owned the plane, the battery has been in the aft position, so I don't know (other than the holes (filled) left in the firewall) how the old battery was positioned. Looking at my G-35, it looks like the battery will have to go in with its long axis perpendicular to the firewall, given the amount of space available. Is this how the original battery was positioned? I know the G-25 is a good bit smaller. My mechanic stated that the tradeoff is that the heat inside the engine compartment may decrease the battery life, but will aid servicing the battery and increase safety since there would be a shorter distance between the battery and master relay. I wouldn't mind a little more weight up front since I'm almost always skirting the aft CG limit with my aux fuel. Thanks, Steven Jackson '75 AA-1B Ser# 0534 (Collier STC) O-320A2B N1434R L22 Yucca Valley, CA