bencpeters

I wouldn't use it prophylactically in clear air at those temps, but there actually were a number of clouds (e.g. visible moisture) in the area - tops were in the 12-14k range from a major winter storm below - that's what got me playing with the carb heat. I don't want to minimize the seriousness of ice formation anywhere in a non-equipped plane, but the idea of unmeltable carb ice from punching through a cold cloud with inadequate carb heat seems especially concerning. Thanks for the ideas on the heat box flapper, I'll check it out! Is there anything on the carb heat system to check out specifically?

I recently installed a JPI 900 on my 64C. As part of this, I now have a carb temp gauge! I've read about using just enough carb heat to keep the temp out of the yellow arc (which on my gauge is somewhere in the ~10-40F range). However, I was out flying yesterday in pretty cold air (OAT ~-15C @ 12.5k) and even with full carb heat, I couldn't get the carb temp to climb above ~32-33F in cruise (from a no-heat temp in high single digits F). This was a bit concerning to me - I'm somewhat skeptical it would be very effective at melting ice at those temperatures. Has anyone else seen this? What kind of temperatures do others see when carb heat is added? CHTs were ~340-360F and EGTs mid 1400s at the time. Not sure if it's related, but the cabin heat performance is also very underwhelming. I know can be an issue in vintage Mooneys, but when I put my hand in front of the vent with the heat on full, the air is barely warm - certainly warmer than ambient, but it almost feels cool on the skin. I'm no expert on the airflow patterns we've got in these planes, but I was wondering if these are related and/or might be indications the "doghouse" needs to be rebuilt, or something else with the intake/exhaust manifolds being off? Thanks!

Thanks for all the thoughts! I went flying again yesterday evening and took a multimeter with me to do a little debugging. - @65MooneyPilot's suggestion to cycle the master, I tried that, but no luck unfortunately. - I was looking at the troubleshooting guide in http://www.beechcraft.org/vtail/interav.pdf - it suggests measuring voltage to ground on the terminals with master on, engine off. I did that on the voltage regulator only (since it's pretty easy to get leads on through the oil inspection port), and found ~100mv on both (not the same value, but close) terminals - so close to ground. According to that sheet, that means an "open Reg or bad connection" (but not a bad resistor - according to the troubleshooting sheet, a bad resistor connection would lead to values of ~0.4 V on both terminals). Kinda leaning toward replacing the voltage regulator with the plane power one regardless - I trust solid state electronics a lot more and it's not very expensive. But it does make me wonder whether there's bad wiring to the alternator or perhaps a bad connection on it?

Interesting re: the resistor! Do you know what it looks like? These are some photos of the alternator, but I don't see anything that obviously looks like a resistor to me... unless it's under the shrink wrap on the connection between the two terminals near the red line here: Or is the resistor over on the other side by the voltage regulator? I'm not totally sure where I should be looking, but none of the wires look obviously problematic here... Thanks! Other pics:

Hi all, I have a M20C with an alternator conversion. I recently overhauled the engine and installed a JPI 900 with better voltage monitoring. Since then, I've noticed that I don't get charging from the alternator after starting the engine until I run up the engine past a certain point, usually somewhere in the 2000+ RPM range. Before this, I'm seeing battery voltages below 12V with a 6-7 A draw, but after I run up the engine and hit the threshold, I immediately get ~14V, with an initial +20A current that eventually settles (presumably as the battery recharges). Voltages remain constant regardless of load or engine speed for the rest of flight. Talking with my mechanic, it sounds like it's probably a case of a bad voltage regular. I have an Inter Av unit that I believe was installed with the original generator to alternator conversion (prior to my ownership). It's the same unit as before the overhaul, and I used to see power coming from the alternator on the amp meter immediately after engine start, but the JPI is installed in the "Ammeter Configuration" which measures current at a different place than the old gauge, so I can't say for sure that this issue wasn't happening before. Either way, it seems like the voltage regulator is probably ripe for replacement. I was looking at options, and it seems like the consensus choices are Power Plane or Zeftronics. I found this thread comparing options: I'm a bit confused on the Zeftronic part numbers though - looking at models on Aircraft Spruce (https://www.aircraftspruce.com/catalog/eppages/zeftronicsreg.php?clickkey=35105), it looks like the Mooney listed models have some kind of plastic barrel connectors which I'm guessing are the original wiring harness from the OEM part, which was replaced on my plane when the Inter Av was installed and the alternator conversion happened. My Inter Av just has 4 exposed wiring terminals (similar to the Zeftronics R15V0N). Which Zeftronic P/N would be appropriate to install? Do I need to get one of the Mooney ones (R15300 or R1530B), and then find/fabricate the plastic wiring harness? Or is there some other way to install it that I'm missing? It seems like others have installed these successfully on vintage Mooneys, does everyone else just still have the original harness? Thanks!

Hi everyone! I'm researching GPSS setups with an existing STEC-30. My research so far has led to either a G5/GI-275 HSI with autopilot interface or a ST-901 being required to provide GPSS info from the navigator to the STEC. However, I was looking at the GTN650xi spec page and noticed that it lists "autopilot compatibility" as a feature, and the Aircraft Spruce page (https://www.aircraftspruce.com/catalog/avpages/ngar650.php) shows STEC-30 in the list of compatible autopilots. Does this mean that the 650xi could drive a STEC-30 directly from the GPS or is a G5/GI-275 still needed in the middle? If so, is this a "new" feature for the GTN-650xi vs the old 650? Other than that it seems like the main differences are a faster processor and nicer screen, not much else different? Thanks!

Interesting plane! What's the "conventional wisdom" on the Continental 6 cylinder IO-360 vs. the standard Lycoming 4? Maintenance, TBO, fuel burn, etc? I've tried a couple of google searches, but most quickly end up in holy wars ;-)

Thanks! Definitely let me know who you are using, I'd be curious. I gave LASAR a call too, we'll see what their availability looks like, but it'd definitely be easier to get it done somewhere closer, especially if it ends up taking more time than a single day.

Hi, new member here! I'm looking at an M20C in the Reno area, and I was wondering if anyone had any recommendations for a good mechanic in the greater area to go to for a PPI? Thanks! Hopefully joining the ranks of Mooney owners at some point in the near future...