Trying to figure out leaning, etc.

[chrixxer]

I'm starting to compile performance numbers for the YoloBird (1966 M20E, no mods, 430 hour IO360, 180 hour Hartzell 2-blade). I think (hope? pray?) I'm leaning correctly, but IDK. The Arrow I used to rent (also an IO360) I was taught to use the JPI-700 in "lean finder" mode and shoot for ~1385 EGT (no CHT probes). I have no idea if that's good or bad, honestly.

I've been trying to lean using the digital E-1 EGT, and monitoring the OEM Garwin CHT. I don't have any fuel monitoring equipment, except the OEM Garwin quantity (in pounds) indicators.

It seems she likes to fly at about 1250 EGT, and peak EGT seems a lot lower than I'd expect. But I'm not sure I'm doing it right.

I've been pulling back the mixture fairly slowly (usually just using the vernier control and rotating, once pulled back about an inch or so) and watching EGTs climb. When they start going down, and especially when I feel a loss of power, I've been rotating back in, and watching the EGTs fall. I've been shooting for about 50° ROP. She seems to peak at about 1315 at 10,500' cruise, 20-21" MP (boost on), 2500 rpm, cowl flaps closed. I've been shooting for 1265 but usually end up around 1230-1250. (Even with the digital read-out, it's hard to be exact with this one.) CHT is usually towards the end of the green arc, below 400° - probably 380°?

What has me confounded is, I'll often see the EGTs climb back up as I enrichen - which, if I've properly found the peak EGT when pulling back, shouldn't happen, right? If I enrichen through that point, they'll start to go back down.

I'm seeing TAS speeds in the 145-154 knot range at 10,500 (I'll develop this chart further as I fly her more, now that I know all the parameters (inches Hg in the Kollsman window, OAT, etc) I need to record. I've been averaging, at altitude (10,500-11,000') a little over 9 gph per tach hour (which includes time on the ground).

A CGR-30P is on my list, after a non-intermittent transponder (ATC wasn't sure if it was my ancient KT76A or their own radar coverage over the mountains, but better safe than sorry), and maybe some interior work. But for now, how do I make sure I'm not killing my engine?

	IAS (mph)	Pressure	OAT °F	Altitude	Density Alt	TAS (mph) http://indoavis.co.id/main/tas.html	TAS (mph) (rough 2%/1000')	TAS (kts)	GS (kts, GPS)	Notes
7/5/2017	137	29.97	60	10500	17247	167	165	145.2	124	20" MP, 2500 rpm, 1240 EGT
7/5/2017	140	30.18	68	10500	13102	171	168	148.7	132	21" MP, 2500 rpm, 1315 peak(?), 1265 EGT
7/5/2017	145	30.25	68	10500	13024	177	175.45	153.9	130	Head wind (10mph per ForeFlight)

[Gry101]

This may help ... https://www.avweb.com/news/pelican/182084-1.html

[kortopates]

12 minutes ago, chrixxer said:

But for now, how do I make sure I'm not killing my engine?

The safest way is to get that engine analyzer and learn how to use it and learn about the "red box" as an area to avoid when operating your engine. 50 ROP is right in the red box if not operating below 65% power. So read all the pelican perch articles on avweb.com or attend the Advanced Pilot Seminars on-line or in person class to learn about this.

For now, till you have valid instrumentation, your best bet is operating at cruise power settings below 65% since below 65% there is no red box and you can run safely at peak. But from 65% and up you need to avoid the red box by either operating sufficiently LOP or ROP. Gami's FAA approved advice attached is very good and conservative advice on where to put the mixture both ROP and LOP and will thus keep you out of trouble: afms-gamijectors rev ir.pdf.

But don't delay on the engine monitor! 

p.s. check density altitude on first flight

Edited July 6, 2017 by kortopates

[HRM]

Frankly, I think you can throw it all out the (little pilot's) window. I have found with my E that I just pull back on the mixture 'til I sense a little roughness, then turn her in until it smooths out and there you have it.

GAMI spread is like 0.3 per MVP-50 data and Savvyanalysis. I use the monitor to keep my CHT's in line.

[chrixxer]

23 minutes ago, Gry101 said:

This may help ... https://www.avweb.com/news/pelican/182084-1.html

Not really, as I have a Lycoming engine and no proper per-cylinder monitor... Also, my numbers don't look anything like his, or what I've been trained on (e.g., "peak" (?) EGT around 1300)...

Edited July 6, 2017 by chrixxer

[Cyril Gibb]

Your training was incorrect.  Sorry.  Peak egt varies according to many parameters, some as trivial as where the installer drilled the holes in the exhaust. Read carefully the suggested info above.  At the moment, you're not doing your engine any favours.  I'd follow HRMs advice until you get it sorted out.

[jetdriven]

For these small lycoming, the red box doesn't really start until 75% power 

[Bob_Belville]

• The absolute value of EGT is practically meaningless. 1300 or 1500 - you shouldn't care.
• What you should care about is degrees ROP or LOP. If you slowly lean - using the vernier on the mixture knob - the EGT will go up until it doesn't go up - it peaks - and then it goes down. Take note of that peak temp. (When your '66E was shipped it had a single prob Alcor EGT meter. It was marked in 25 deg F segments but had no actual temps. It had a movable needle to position at the peak temp so that you could easily move the mixture in until you were the reached the ROP delta temp you wanted.)
• At higher power setting you should run either 100 ROP or 25 (or more) LOP to be confident you cannot harm the engine.
• As Paul points out at lower power settings you will not harm the engine at any mixture you choose.
• At 10,500', Full Throttle, and 2500 RPM you won't be (much) over 65%. particularly in the summer, at lower altitudes you'll have to pay more attention to % power.
• Read the first bullet point again. 

You have one of the very best models and year that Mooney ever made, enjoy!

[gsxrpilot]

• The specific EGT numbers are meaningless. The only way EGT matters is +/- peak. As you only have one EGT probe, you really have no way to determine peak. So you might as well ignore the EGT gauge.
• Leveled out in cruise, make sure you're at 65% power or less. Then lean to whatever you like. You can lean for best power, speed, fuel flow, etc. At 65% power or less, you can't hurt the engine.
• Fly high enough that even full throttle is 65% power or less. 
• Get an engine monitor ASAP. Learn to use it. The hours you'll add and the fuel you'll save will more than pay for the engine monitor.
• Insight G2, JPI EDM-900, or EI MVP-50 are the three you should be looking at. Choose the one that fits your budget best.

[carusoam]

So, if I get this right...

1) you used to use a JPI in another plane... pretty irrelevant now...

2) It didn't have CHT data... less relevant here...

3) you are quoting actual exhaust temp value as if it were meaningful... it isn't.

4) your bird has a single EGT.  The way most Mooney's were built since 1960...

5) Your bird has a digital display of the single EGT.  That is a step above standard fare. Won't help much.

6) follow any POH for leaning procedure.

• lean until the single EGT peaks
• enrichen until the EGT falls to 100°F lower than peak.

7) if you change the MP or RPM, lean again.  Mixture changes with the other inputs....

8) know what the red box is and how to avoid it...

9) without knowing all the EGTs and CHTs you are working in an area where precision isn't available...

10) high or uneven EGTs and CHTs can be a lot more expensive than any JPI...

11) Experiment with an MP of 20" (nice round number, low power setting, generally cool CHT territory)

12) Do you know our used JPI sales guy?

A used old one is far better than saving for one...

13) know that bad baffling, or clogged injectors, is probably going to go unnoticed...

14) I got a stuck valve on my first M20C within the first 10 hours of ownership... a JPI would have advised before it happened.  Would have helped problem solving during the E-landing...

15) get one When able.

16) Install with Your mechanic.

I took longer to type than the other guys...,

-a-

[Bob_Belville]

Here's the sort of panel a '66E deserves: 

[chrixxer]

Mine's gonna look somewhat like that, one of these days.

Current:

• Sigmatek suction gyros, etc., work well enough and the heading bug drives the S-Tec System 30 with Alt. autopilot, all installed when I bought her.
• GX55 GPS with a repaired screen ($325 for the fix). Autopilot-linked. (Super nice...)
• SL30 providing, basically, COM1/COM2 (standby monitor) and NAV1 (driving an IND-351 with glideslope) and NAV2 (standby monitor).
• KT76A (flaky).
• Factory tach, Garwin cluster, MP/FP gauge, and an EI E-1 EGT monitor.
• Ugly cowl antenna routed into the cabin for handheld use (emergency and ATIS / clearance).
• Stratus 2 for GPS/ADS-B In/AHRS.

Phase 2:

• Interim KT76A replacement, so I can fly legally (home airport is inside the LAX Mode C veil).
• EI CGR-30P engine monitor (especially while there's a rebate on), with fuel flow monitors.
• Redone panels, left and right.
• GAMI injectors?

Phase 3:

• GTN-650 replacing the GX55.
• GTX-345 transponder replacing the KT76A (or equivalent).
• GI-160B CDI.
• Belly COM antenna.
• Antenna switch on the COM2 (roof) antenna, for emergency handheld use.

Phase 4:

• Aspen PFD1000Pro or dual Garmin G5s (if the G5 HSI can ever drive an autopilot under the STC).

Somewhere in there, new interior and touched up paint.

 

[gsxrpilot]

When are you flying home? I've got a KT76A you could have really cheap... but I'm not at home in Austin.

[chrixxer]

6 minutes ago, gsxrpilot said:

When are you flying home? I've got a KT76A you could have really cheap... but I'm not at home in Austin.

I'm home now. The local flight school has a KT76A they'll give me, working when pulled, but I fear that's just kicking the can down the road. That cavity coil / the heat that the '76A generates, etc...

[gsxrpilot]

5 minutes ago, chrixxer said:

I'm home now. The local flight school has a KT76A they'll give me, working when pulled, but I fear that's just kicking the can down the road. That cavity coil / the heat that the '76A generates, etc...

I'd kick that can down the road and get yourself an engine monitor. 

[Gry101]

The article is not just for Lycoming engines. All engines can be run LOP. I am not sure about the tubos though. I understand you do not have an engine monitor, yet. However, it is still very important to read the article as the information is valid and valuable. Since you only have a single point EGT at this time, lean to peak EGT, then richen at least 100F. As stated above, you could also lean until rough, then richen until smooth. That will probably put you around 50 lean of peak or so. Once you know what temp os peak, you will never have to go there again. Just lean to at least 100 ROP, or 50 LOP. 

[Andy95W]

3 hours ago, jetdriven said:

For these small lycoming, the red box doesn't really start until 75% power 

Byron- I've never heard this, and I'm not questioning your knowledge, but I'm curious what information you base this on.

[DXB]

4 hours ago, jetdriven said:

For these small lycoming, the red box doesn't really start until 75% power 

I hope you're right because this is indeed how I operate my O-360.  Also visualizing the red box for each individual cylinder in a carb'd plane as you lean is impractical.  I would be curious to have more information on this issue though.

[carusoam]

3 hours ago, Gry101 said:

All engines can be run LOP.

Might be an awfully strong statement that covers a lot of territory...

Some Mooney air intakes are not very well balanced, some fuel distribution isn't very well balanced either.  Where all engines operate while LOP may not be very useful. 

Welcome aboard,

-a-

[jetdriven]

4 hours ago, Andy95W said:

Byron- I've never heard this, and I'm not questioning your knowledge, but I'm curious what information you base this on.

Lycoming' own documentation. You can run it at peak EGT, or 50 ROP at 75% power and below. I choose to run it LOP at up to 83% power (11gph) and it still runs 330 CHT like that. Usually it's 65% for cruise for me. 

These engines aren't made of glass. Just don't run them where they exceed 400 CHT continuously,  to get maximum service life. 

[KLRDMD]

EGT responds more quickly than CHT, but CHT is more important to engine longevity. Both are important but used differently. +/- 1300 EGT is a reasonable target to lean to during the take-off roll and in climb. In cruise, I would suggest leaning to peak (EGT), then just a touch more lean to put you in the 10-20º LOP area, assuming you're above 8,000 ft. and your engine runs smoothly there. That will give you a nice cruise speed with great fuel flow and low CHTs.

[ragedracer1977]

I've been following savvys advice and adjusting mixture one way or the other to keep my highest CHT at 380 or less. Busch basically seems to suggest ignoring EGT.  Thoughts?

[chrixxer]

When I'm properly instrumented, CHTs. But the Garwin is hard to see/read and doesn't move much; I see immediate and large movement on the EGT, while CHT seems to hover just shy of the 400 mark (I have markings for 200 and 400 and then, just past 400, a red line; not much precision information in that presentation).

[Godfather]

I'd probably just use the single EI egt guage. Lean to peak and enrich 125 degrees...you really don't have any idea what the other cylinders are doing.  Buy a used jpi 700 asap. 

[chrixxer]

On 7/8/2017 at 8:48 AM, Godfather said:

I'd probably just use the single EI egt guage. Lean to peak and enrich 125 degrees...you really don't have any idea what the other cylinders are doing.  Buy a used jpi 700 asap. 

I'm still finding two peaks with the EGT (while CHT never seems to move, always right around 380).

I've got a request out for a quote for a CGR-30P, while the rebate's on. I find JPI really user-unfriendly (company and equipment alike)...