On a related topic I find almost no one checks the ammeter after start. If the starter contractor fails shut the starter will remain energized after the engine starts. If this happens the ammeter will instantly peg itself and you need to shut down right away or it is going to get expensive.
I also like to monitor the ammeter right after start. The charging load should drop rapidly. If it is still showing a high charge a couple of minutes after start you have a problem you should investigate.
Generators / Alternators Off for Start?
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Colonel
- Posts: 2519
- Joined: Wed Jan 15, 2020 10:02 pm
- Location: Over The Runway
I'm pretty sure no one checks the ammeter, ever. I try to look at it after start
after ALT FIELD on, to ensure that it is on the right side of zero.
However. I remember a couple decades ago, flying along in the Mooney 201
(M20J) and the radios started to act funny. Turned out the little field wire had
vibrated and broken off the back of the alternator right at the AMP crimp connector.
Ahem.
That's the nice thing about kerosene stuff - it has the idea of caution lights which
draw your attention to bad gauge indications - discharge, low volts, low vacuum,
low oil pressure, high oil temp, etc - which many a pilot has not noticed until too
late.
I have these fancy engine monitors and they actually have this feature - when
something is out of range (certification limits) you get yellow/red indications
on the screen. One neat feature is mag failure - it tells you which mag is not
functioning when you test them, with these virtual red caution lights.
I'm sure the homebuilt stuff does all this. Too bad no one makes an STC'd
box with caution lights for certified. The thing is, by the time you add all the
transducers and such, you might as well spring the $$$ for an engine monitor
with data logging, which is gold.
after ALT FIELD on, to ensure that it is on the right side of zero.
However. I remember a couple decades ago, flying along in the Mooney 201
(M20J) and the radios started to act funny. Turned out the little field wire had
vibrated and broken off the back of the alternator right at the AMP crimp connector.
Ahem.
That's the nice thing about kerosene stuff - it has the idea of caution lights which
draw your attention to bad gauge indications - discharge, low volts, low vacuum,
low oil pressure, high oil temp, etc - which many a pilot has not noticed until too
late.
I have these fancy engine monitors and they actually have this feature - when
something is out of range (certification limits) you get yellow/red indications
on the screen. One neat feature is mag failure - it tells you which mag is not
functioning when you test them, with these virtual red caution lights.
I'm sure the homebuilt stuff does all this. Too bad no one makes an STC'd
box with caution lights for certified. The thing is, by the time you add all the
transducers and such, you might as well spring the $$$ for an engine monitor
with data logging, which is gold.
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RBK
- Posts: 24
- Joined: Wed Feb 03, 2021 5:15 am
I remember those RST marker kits, Colonel. It's too bad kits are a thing of the past.
I soldered together this Rocky Mountain Instruments engine monitor for my RV a little over 20 years ago. Seems to me it had a few hundred resistors, capacitors and chips and it took 20 to 30 hours to complete. Sadly, this particular kit is no longer available since Dynon came out with pre-assembled ones with fancy colours for not much more money.
It's still going strong, and has user defined alarms for the various parameters. The only real downsides are that it only monitors EGT/CHT for one cylinder at a time so I have to select which cylinder with a rotary switch on the panel, and the screen doesn't like to get hot and goes dark , which is sometimes an issue in the summer on the ground until you get some air flowing through the cockpit.
Not sure if the pictures will come through, but here's one from a flight this morning and another from the construction process.
Oh, and by the way, I leave the alternator off until after start, plus I have the avionics on a separate switch and my bus has good overvolt protection.
I soldered together this Rocky Mountain Instruments engine monitor for my RV a little over 20 years ago. Seems to me it had a few hundred resistors, capacitors and chips and it took 20 to 30 hours to complete. Sadly, this particular kit is no longer available since Dynon came out with pre-assembled ones with fancy colours for not much more money.
It's still going strong, and has user defined alarms for the various parameters. The only real downsides are that it only monitors EGT/CHT for one cylinder at a time so I have to select which cylinder with a rotary switch on the panel, and the screen doesn't like to get hot and goes dark , which is sometimes an issue in the summer on the ground until you get some air flowing through the cockpit.
Not sure if the pictures will come through, but here's one from a flight this morning and another from the construction process.
Oh, and by the way, I leave the alternator off until after start, plus I have the avionics on a separate switch and my bus has good overvolt protection.
You do not have the required permissions to view the files attached to this post.
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Colonel
- Posts: 2519
- Joined: Wed Jan 15, 2020 10:02 pm
- Location: Over The Runway
Very nice! I remember those 
PS Everything is SMT these days. I don't do that. I get kids with these funny microscope soldering stands to do it for me.
The power of modern embedded SoC's is mindblowing. People up in Oregon do a very nice job on these:
PS Everything is SMT these days. I don't do that. I get kids with these funny microscope soldering stands to do it for me.
The power of modern embedded SoC's is mindblowing. People up in Oregon do a very nice job on these:
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