Lean assist: help ?

[txnoodles]

First off I love this plane. It's beautiful inside and out. If I think how much a carenado bird cost and what you get with this bird for a  little more it's a joke.

Now to my question: Any one can explain/show  with a vid or a tutorial (fool proof instructions) how the lean assist works  ? I  run a search on you tube and watched a few vids  which did help a lot. I can't use the assist on our  SR22 tho.

All help appreciated.

[jeff64]

Sorry no video, but the idea is the following.

Leaning is a matter of Exhaust Gas Temperature (EGT).

When you lean, the EGT will rise, till it will reach a peak. If you continue to lean, the EGT will drop (until a point where the engine will run roughly and eventually...shut down).

 

Best power is done around 75°F on the rich side of the EGT Peak. This is called "75 ROP" or "Rich of Peak". You will burn more fuel, but will go faster.

Best economy is achieved around 75°F on the lean side of the peak. This is called 75 LOP, or "Lean of Peak". You will go slower, but will consume less fuel.

 

When you click assist leaning and start to lean, there will be a little indication which will tell you which cylinder will reach the peak the first (if you seek for ROP) or the last (if you seek LOP), then which will tell you the temperature difference between current and peak.

It helps you in finding the correct setting for 75° ROP or LOP.

 

Your engine is really sensitive, and one of the most precluding factor on the long term is you cylinder temperature. In cruise, but especially in climb and descent, you must :

- keep the CHT below 380°F (the best), or at least below 410°F. Above 410°F can still be inside the limits, but will not be good engine management.

- avoid shock cooling, especially in descent. I think I heard a rule of thumb is to limit the CHT reduction to less than 50°F per minute.

But hey, this is simulator. Fucking an engine or a cylinder is not as expensive as in the real thing !

Edited July 27, 2020 by jeff64

[txnoodles]

12 minutes ago, jeff64 said:

When you click assist leaning and start to lean, there will be a little indication which will tell you which cylinder will reach the peak the first (if you seek for ROP) or the last (if you seek LOP), then which will tell you the temperature difference between current and peak.

In the videos there was a  "first" or  "last"   inside a blue box but in the sim I just see blue boxes flashing but it's not showing which one is which ?

[sdflyer]

Also lean engines all my life, but I have never used auto assist.  Explaining general theory of leaning doesn't really give insight in auto assist

[jeff64]

assist will just give you the delta peak, meaning the difference between current EGT and Peak, and should show you which cylinder is the first / last to peak.

 

You see it in this video

 

Edited July 27, 2020 by jeff64

[qazme]

@jeff64 That's the issue. This simulation of the SR doesn't show you the first and last to peak, or the blue peak lines. The blue box just continues to bounce around and doesn't really let you know when the last peak was found. Unless maybe I'm doing something wrong as well? I get a "peak" reading but not sure which cylinder unless that only populates when all 6 have reported which I've defaulted to, then I go either -50 for lean of peak (economy) or 75 rich of peak for power which is from the SR-22 manual.

If someone can speak to the actual procedure from this simulation that would be terrific - though I can't complain I done up to 825mi legs in it so far and had fuel left.

Edited July 27, 2020 by qazme

[Coop]

Got first/last annunciation on the list to get added!

[txnoodles]

2 hours ago, Coop said:

Got first/last annunciation on the list to get added!

Sounds great thanks.