Any heads up on how/if/when to use the lean assist function on the Avidyne Entegra MFD ( eng page) pretty much welcome !
Aircraft is a SR22 G3 TN
Thanks
same plane.
here’s what i learned so far: i’ve never used it. the guy that i bought the plane from, as well as my CSIP told me to set the mixture at full rich below 3500’, 16.4 gph above 3500’, and use the throttle to control % power.
as i’ve learned over the last couple weeks, that’s not how you use a TN.
now the lean assist function on the eng page begins to make sense when used in conjunction with the cruise checklist.
on my next flight i will try it
To be honest I rarely use it. With a SR20 G2 in addition you have an altitude compensating fuel pump, full rich is fine until you get to cruise altitude and if you want ROP, just dial % power with the power lever. LOP I pull power back to 5% more than desired, than lean until I have the desired power setting. Power will slightly increase (more without altitude compensation) first and then drop. If it drops again you are LOP and far enough as well with 5%. From about 6000ft you will usually just pull power back until 2500 RPM and MP drops in a NA, then fly WOT 2500 RPM and control power % with mixture. You can fly peak EGT as there is no red fin from a certain altitude for NAs, there is simply not enough air.
You arrive at the exact same settings for power and mixture if you use lean assist in my experience, just much slower. With a TN you will not get out of the red fin just by altitude, but by leaning 5% power away. So try setting 75% power full rich, lean until you have 70% and note the fuel flow. Back to full rich 75% and use lean assist until you have best economy and compare fuel flow. I expect no surprises.
1 Like
Just use the lean assist to help you find the sweet spot.
Ihave a Perspective, but I think it is pretty much the same idea. Set up the lean assist page. From full rich, full throttle pull the throttle to 29.5-30” MAP., should settle to around 2500, the higher the RPM the better in my experience. Pull the mixture and note the last to peak. Continue leaning until the last to peak is 50-75 below peak. I haven’t run the lean assist since I first bought the plane.
My TN is set so the blade is in cruise config at 2540 RPM. (Factory set up is 2500 +/-) After leveling off in cruise, I wait 2-3 minutes for CHTs to stabilize before leaning. IAS will get up to around 160. I pull to 2540, 29.5-30 “, then pull the pull mixture to 16.5. That puts me at around 78% and that is where I spend most of my time… when I am just out for fun ir doing maneuvers, I can pull as low as 13.5 (65%) at that throttle setting without it running rough. From there just manage TIT and CHT. On really cold days, I can run higher (17.5) fuel flow, but rarely do. On really hot days I may have to run closer to 16 to manage CHT and TIT.
The only time I am full rich is climb out and final. Even if I am cruising at 1000 AGL unless it is a very short hop.
Once you’ve used lean assist a couple of times, you’re good. The settings are consistent.
1 Like
I use it all the time, but not in the way I think they intended. I fly a G2 20, I normally do a big mixture pull down to about 9GPH, this gets me on the lean side of peak for most flight levels that I operate.
After the pull, I use the lean assist function to find the peak and pull back to close to 50 degrees LOP with wide open throttle (i.e. peak MP at 2500 RPM).
This way I don’t use some set fuel flow, I use the data for how the engine is operating and go from there.
François, join COPA. There is a ton of information on our member forums (well over a million posts) and you can quickly get all of the answers you need. Few members even look at this Guest forum. Guaranteed it’ll be the best $95 you can spend in aviation.
4 Likes
Hello Gordon,
I have to say I’m pretty wary about forums in general, and the samples I have received on various topics such as dfc90 ap and lop ops are not here to soften my reluctances…
Are you suggesting I would get access to sounder opinions had I registered for the full copa membership ?
Fr.
1 Like
I’m not Gordon, but, most of us do not monitor the guest section. Not sounder opinions, (Sajay has a great method) but there are a few ways to do it and they all work.
Only $95/year. If you don’t feel like you get $95 worth of information then we’ll give you your money back.
Such a deal!
Not Gordon, but I’ve been a member of COPA for over 15 years and 2800 flight hours in an Avidyne G2.
There are several threads on the main forum about lean assist, engine management, and the Red Fin that are well worth exploring. You also have the option of cancelling membership and getting your money back if you don’t like what you see there.
Of course, if you don’t want to do that, you could just lean to under 13.5 GPH and you would be more or less OK. But then you wouldn’t get the benefit of all the other guidance I have had over my years as a member.
Over to you…
1 Like
The material, and audience, is far broader. The search function alone would provide you with access to a wide range of answers and opinions on anything Cirrus. For example, particularly on leaning using the Avidyne lean-assist feature, there is a veritable library of information on LOP operations and there’s even a specific step-by-step documented procedure for doing so, accessible right here, which describes use of the Red Fin graph
No.
Every engine is different. There are no black and whites. Percent Power is meaningless. There is never a reason to be full rich prior to landing. Safe and efficient use of these TN engines requires training and nuance.
OP, hire a TN expert to get you good information.
Or read the Tornado alley Supplement
2 Likes
THIS!!
TNs are different and the advice you take should be from TN drivers… I have about 900 hours in my TN and would be happpy to chat. Join COPA, it is a great investment.
1 Like
“And” read the POH supplement.
2 Likes