[db8]

Not to beat a dead horse, but there is another discussion similar to this concerning LOP ops and cruise performance. I would like to break that down further (without hijacking that thread).

I do not have much civilian time dealing with mixtures, props, etc prior to building the 8 (was a military guy and airline guy now). So I am still trying to figure out a no-kidding, no-brainer standard way of setting the ole levers up when going on longer cross countries (I mostly fly local and generally not more than 60 miles for a burger). But I have yet to figure out a tried and prooven good technique of setting levers up on cross countries. Feel free to throw in what you do for short small hops too.

I have read many of Mike Busch's comments on this, and I think he's great. Since his article a few months back, I have decided I will use WOT (as he recommends) when traveling above say 5K' (below 75% pwr)? When I travel somewhere on a cross country, I don't have to get there first (or last) or whatever. I don't mind being in the plane a little longer to get better fuel economy. At $6/gal, the scenery looks much nicer for a little longer flying when that two gallon savings can buy a few (more) beers.

In the beginning, I use to slowly pull the power back to get to peak, then play with it to get 75 degrees ROP. Then I read about LOP. I did the Airflow Performance fuel injector nozzle changeouts as per their callout so I can fly LOP. Then I read another of Mr. Busch's articles on a variation of "the Red Box" and thought maybe I have been pulling the mixture back too slow to find peak; therefore, staying in the majenta or red area too long? If I do the BMP (Big Mixture Pull), I then don't have to worry about the box by going to the lean side quickly. But since peak is often in the box area and we don't want to be there, I need to figure out a good LOP technique. Ideally, I would like to figure out a relatively easy way/technique for setting the throttle, prop & mixture when I travel cross country from point A to B using the least amount of gas (best or max range I assume would be the term)?

What are some techniques that you guys use with a constant speed prop, parallel valve, fuel injected 360 that keeps you away from the boxes? I know this varies with temp, alt, etc, but I'm sure some of you guys have some great technique/s that you might want to share? Is WOT really the best? It seems to be based on the way Mike presented it in his article.

When I got my private 34 years ago, I do remember (kinda) on cross countries pulling the mixture back till it ran a little rough (a little like BMP) and pushing it up a little after that. That might work here, but what do you push it up to after that? Say +50 degrees EGT from the sputter? Once again, I know this can vary with altitude, temp, etc, but looking for just a general rule if there is one. I'm sure using the MPG feature of the EFIS is a help also, but the throttle, prop and mixture have to be set somewhere to start without doing engine "damage" in the box area.

I do use the technique of leaning the EGT to keep it the same on climbout after passing 1000' AGL or so, and like that. Thanks.

 

[jetdriven]

We have an IO-360-A3B6 in an Mooney 201. Below about 3500 feet density altitude, I leave the throttle wide open, set prop for 2500 RPM, and pull to 10 GPH. I then double check this is LOP.

Higher altitudes are similar, WOT, 2500 RPM, and pull until the EGT peaks, then go 15 degrees further. Monitor a few minutes the EGT doesnt drift, then watch CHT to not exceed 380. Done. Lycoming says you can operate at peak EGT at 75% and below, and I dont sweat the mixture pull. I will get it s few degrees ROP rather quickly, then slowly (over a period of a minute) go to 15 LOP. Sometimes I pull it to LOP quick and then richen to peak, then lean again. It doesnt matter. At low altitude it does, I pull it to 10.0 GPH over a 3 second period.

If you need more range, fly at a lower % of power. Less RPM initially, then if its still too much speed, leaner from peak. I try to make it SOP not to run leaner than 50 LOP, I think the BSFC gets worse beyond that.

We flew 800 NM on 40 gallons with the 201 like this, at 50% power. 7.4 GPH and 128 KTAS, and this is a certified 4-place airplane.

 

[db8]

Simple

That seems good and simple.

I have a Hartzell BF prop. For a 180 HP engine, there are no restrictions. For a 200 HP non-counter balanced crank, there is a restriction of when above 24" MP, only momentarily be between 23,500 and 25,500 RPM. I have cold air induction, electronic ignition and 9:1 pistons, so I am guessing I am pushing about 192 or so HP. I err to the conservative side and follow the restrictions. When I get higher, it's not a consideration (of course) since MP drops accordingly.

 

[zav6a]

LOP

Get a good fuel flow meter. Take some notes in various conditions and you will quickly know where to run. A lot easier than chasing egts every flight. It is surprising how reliable and consistent it is regardless of temp and ATM pressure. Maybe 2 tenths gph one extreme too the other.

 

[db8]

Duane. Do you too use WOT and 2500 RPM? Do you change your RPM based on your altitude or have a set number regardless. Just curious.

 

[zav6a]

Rpm

Unless I am loitering over an area or otherwise purposefully going slow, it is wide open and yes I do use 2500.

I seldom get to fly below 7000 feet but when I do, I take off ROP, 2700, then throttle back, set 2500 and 23 or 24 inches for cruise. Then quickly dial in my LOP fuel flow. I don't think I have too throttle but no need to burn all that gas at high power ROP.

Using fuel flow instead of EGT is just a heck of a lot quicker and allows you to keep your head outside. You can always fiddle with it when you are not busy with flying the plane.