[gnuse]

I have read the VM1000 manual over and over and it is not much help, at least in my case.

I have not noticed the "bar graph for that EGT will begin flashing...". Maybe I missed it and continued leaning or maybe I don't know what I am looking for.

Any help or tutorial in using this instrument would be appreciated. Thankfully, I know that I am not the only person looking for this help.

 

[Omega232Devils]

VM1000

George,
I have the old VM1000 (Non 'C' model). The leaning function when selected will place all the bars even on the lower line (where CHT values are normally seen). You should pull the mixture bar back to get a continuous rise of no more than 1 bar per 2-3 seconds (I believe is what manual reads). If you go to slow, you will get a false peak, i.e. the reading is one of those rounding numbers since the display goes by 10s. To avoid this, keep the mixture coming, when the 'screen flashes', it will only flash the cylinder that has peak. Stop leaning, wait for it to go steady and then you can go LOP or ROP as you wish. If you continue to lean when it starts to flash, it will override it and not flash. My guess is that you are pulling through the peak and not seeing a flash. So, go slow, but continuous.

Just so we are all on the same page, can you list: Engine, FI or Carb, EI or mags

Dan

P.S. You may want to look into the EAA webinar that Mike Busch put on regarding leaning techniques, as well as his most recent article in Sport Aviation about the red-box/red-fin. He doesn't recommend using the leaning function.

 

[gnuse]

Thanks, Dan.

I have watched the Mike Busch webinar this week.

IO360A, 200hp, mags. My VM1000 is also the older version, non-color.

Thanks for any help. Your description already shows that the manual is sadly lacking, at least to a novice.

I assume you mean the entire vertical line of "diamonds" will be flashing at peak.


George

 

[eaglen92ce]

I also have the old VM1000 in my RV6. My lean mode was not functional when I bought the plane. Unfortunately others have also experienced this failure mode. I bought another CPU (the big gold box) and now have a functional lean mode function. When you push the lean mode button your two sets of bar graphs (CHT and EGT) should become one bar graph with all bars equal (normalized) representing the EGT at a finer scale. If you are not getting this you may have a problem with the unit. Some have suggested that the fault can be the result of a low CPU memory battery. I switched the battery on my first CPU and it did not fix my issue. The new (used) CPU did.

There is a guy named Reggie who posts on this board some. he repairs these units and sells parts. He is likely our expert on the VM instruments. Hopefully he will chime in. It really is a pretty nice unit, definately a little ahead of its time when developed!

 

[gnuse]

I do get the two "diamonds" at the top and the reset on the EGT columns when I hit the #1 button.

 

[Omega232Devils]

Not sure about the Diamonds

George,
First let me apologize, my plane is 45 minutes away and after 10 years in California, I have turned into a fair weather flyer! (It is 30deg in Rhode Island today!) Otherwise, I would go to the hangar and take a video of the lean mode to show you.

As presented above, when you press the lean button (button #1) the CHT and EGT bar graphs combine into one, then your lean mode is functioning correctly. If you start the leaning process as I described in the first response, you will see the bar graph for all 4 cylinders rise. (Not always equally) When the first of your cylinders peaks, the bar graph for the "single cylinder" will flash. Not the graph for all 4 cylinders and not the entire bar graph for the single cylinder. Only a single bar of the peak cylinder will flash. It will only flash 3-4 times. If you pull through it, you will miss it.

Couple things you can do,
#1) Reverse the process, climb to altitude where you will not produce 75% power, pull the mixture till the engine runs rough. Enrichen just enough to smooth. Now enter the lean mode and enrichen the mixture and see if you can peak a cylinder this way. If you can't, you aren't able to run LOP with standard Magnetos. (With FI, you should be able, but not guaranteed)

#2) If you pull the mixture to rough, then enrich to smooth, look at your EGT/CHT data. It will tell you which cylinder is hottest in the CHT column and which cylinder peaked first represented with a P and the cylinder number (i.e. P3 = cylinder #3 peaked first.) Use this info to focus your attention on your next attempt at leaning, by focusing on the cylinder bar graph for the cylinder that peaks 1st. What you may find is you are pulling through the 'flashing' as it is not as noticeable as the instructions are written to have you believe.

Reggie Smith (Glas467) on the forums IS the resident expert and we share a hangar. He has helped me on numerous occasions. Unfortunately he is currently deployed, so his response may be delayed as a result.

Let me know if you need any more help and next time I fly, I will grab a short video of the process for you.

Dan

 

[gnuse]

Dan,

I will keep trying. Your offer of a video would be great, whenever it could happen. Your advice is a tremendous help.

 

[RV10inOz]

Lean Find functions are not as good as watching the raw numbers. End of story, no matter which EMS you have. Some are better than others but the thermal inertia of the probe and how quick you sweep the mixture creates variables.

Simple method, assuming your engine is a conforming engine and has the F/A ratios well balanced.

1. Level out in the cruise, let the plane accelerate.
2. Close your eyes, and pull the mixture over 3-5 seconds, when you feel the plane decelerate stop there. (yes feel...thats why you close your eyes)
3. Set the lean find function and slowly richen up, and do it slowly so the probes keep up, until you find the first one to peak (this is the richest one)
4. This is now the reference cylinder, so go out of lean find and into raw data and lean back using this one value until you have the correct amount LOP. This depends on the power generated.

At typical higher levels beyond say 7000' use 10-20dF LOP, maybe 10 for that cylinder as others will be past that. At higher power setings say 80-85% you will want to be more like 75-80dF LOP.

If your EMS has a normalise mode, this is the time to use it so that you can see any deviations indicating plug or valve issues.

An occassional check as above is a good idea just to see that the same one is peaking the same way. It might show up a intake leak, or injector plug.

Now you can do this from the Rich side, but at high powers this just heats up the cylinders and is the less desirable way to do it. Of course it is the opposite, you are looking for the last one to peak. But here again when you know which one consistently peaks last you can go straight to it.

Hope this helps!