I don't know if it is OK to run Lycoming engines like the one in my Christen Eagle by IRIS Simulations 20° Lean Of Peak EGT would that damage a engine I've always ran mine 20° ROP or Rich Of Peak any advice is greatly appreciated and will be used as well.

If you have engine gauges that monitor each cylinder temp, then you are safe using LOP, otherwise, no.

In RW, ROP is a good way to carbon up a perfectly good $40,000 engine.

 

 

In the near future, new aircraft will have modern computer controlled fuel injection systems like the family car.

For some reason I've never managed to grasp this concept. Can someone tell me what lean of peak refers to and how to set it? Is it a temperature thing based on EGT/CHT or is it something else?

Google for full explanation but there are 2 schools of thought on the best way to run a gas engine, ROP and LOP.

 

ROP you lean until the temp maxes and the engine starts to run a bit rough, then richen it until the temp shows 50 degrees or so cooler than max EGT/CHT, whatever you are monitoring.

 

LOP is a whole different animal, because unless you have engine instruments that monitor each cylinders temp, you can cook an engine rather fast. Some swear it lenghtens engine life, uses less gas, and engines stay cleaner....not everyone agrees.

Some swear it lengthens engine life, uses less gas, and engines stay cleaner....not everyone agrees.

 

That's putting it mildly.

 

It seems the major proponent of LOP operations sells a fuel injector claimed to allow LOP operations. Gami-jectors? There was a thread about it a few months ago. And outside the flight sim community, I've read a LOT of stuff from people who "didn't agree."

 

In the sim, do whatever you want. Unless the engine is set up for damage, it's all role playing anyway. Pretend you have magic injectors, and experiment with them to your heart's content. I tend to run my sim engines exactly at peak, but not more than 1350 F EGT. You won't start to lose power until you go lean of peak.

 

I'm not sure CHT can be used to monitor this; it's just not a fine enough measurement, and it takes a considerable time to stabilize. In a small engine, I keep CHT at or below 205 C, but that usually takes an air file edit to get the temperature that high. Same with EGT, as normal max temps are maybe 1200 F.

 

Hook

I lean mine to peak then I richen it to 20 degrees ROP for best power I mainly cruise the Christen Eagle II on cross country flights at 23/23 23"MP and 2300 prop or I go 20 degrees LOP

One the sim planes. If the dev uses the default FSX engine model (which most do), you'll receive a setup as follows.

 

FSX doesn't differentiate between different carburettor setups or even fuel injection. One model fits them all. This affects a lot of things, even icing. As for the leaning and e.g. fuel flow readings, those are wonky. Yes, you can lean with altitude gain, but I think the amount of leaning needed is too much. This is also needed for turbo-normalized engines. On the latter, Realair describes that flaw in some detail in the Duke B60 piston manual. Orbx also does in their Lancair IV-P docs.

 

I think you can't ruin the sim engine (default model in use) when it comes to high CHT. It simply won't break, so to speak. You may not even be able to reach too high temp ranges without some tweaking.

 

And the real planes? Well, I'd always stick to the POH/AOM values. Speaking about current docs of course. That's the legally binding stuff and also the one coming from engineers designing planes and engines. You are running into those folks when it comes to warranty issues or maintenance problems. So the high hour count of pilots or the forum discussions wouldn't outpace the manufacturer's recommendations in my eyes. Also, the CHT value is a slow reacting one in regard to much more sensible ones like EGT. Well, you have to use what's there of course (instruments installed).

 

Back on the sim. I think one will have a hard time hearing a rough running engine. Not saying that this sound detail is completely absent, but, as Larry pointed out, the sim may only offer the role-playing setup.

 

This changes when devs use engine models running 'outside' of it. A2A comes to my mind or any of the automatic mixture thingies like on a Aerosoft Catalina. Those can feature details like on the real engines and those mostly include a failure model. For instance, there are consequences to expect when not operating the engine correctly.

 

So if Iris uses the default based model and if the manual doesn't state how the leaning should happen, you have much freedom. ^_^ It shouldn't matter much if you are at peak, slightly lower or higher in that case.

 

 

If you are looking for the rw docs, maybe you are lucky on the Lycoming page. http://www.lycoming....vice/index.html Those feature tips on the leaning and more.

Engine Operation Tips

 

Several booklets are published by Lycoming to provide helpful tips and recommended procedures to help you get the longest service and most efficiency from your Lycoming engine.

 

And AOPA always helps if you are up for a longer text. http://flighttrainin...al/mixture.html As said, the default sim engine model may not offer much detail, but you can still act is if it would.

Here's a nice blog I found which does a great job if explaining the difference between LOP and ROP:

http://www.flyplatinum.com/blog/?p=577

I tend to operate most of my single engine piston GA aircraft a few degrees ROP.

I like to run my 20 degrees ROP and this aopa article that you linked me to is very usefull

Now we're talking! Another great post by CoolP.

 

LOP and ROP is a RW MEGA debate going back many years. I'm sure many fist fights have been started by it in the $100 burger joints over the years. If you are interested, learning about this will give you great insight into not only planes, but the car you drive as well. LOP and ROP is simply the "Air to Fuel ratio" introduced to the cylinders, but in the case of aircraft, they use the cylinder head temps, and the exhaust temps, as a gauge. Your modern family car uses computer controlled fuel injection with a MAP sensor, and a Oxygen Sensor. Your cars computer tries to maintain a "stoich" AFR of 14.7 to 1. This is the perfect AFR in a combustion engine that makes the most power, and reduces emissions. In aircraft, despite the preponderance of computers, engineering, and hight tech avionics, we still think Joe Bob Pilot can control the Air Fuel Ratio manually like it was done on a 1908 Harley Davidson!! It is funny to think that you are climbing into a machine built today with turn of the century ghost still in there! Don't even get me started on "magnetos!"

 

As a person who has done motor work as a hot rodder, I can assure you that both LOP and ROP is BAD for your engine **if excessive**. ROP is a silly way to help cool the engine.... more fuel, cooler burn.... but the trade off is that you are gumming up your 40,000 or more engine (see pic above) and taking hours off your TBO. The same is true for LOP... Less fuel (less GPH), burns hotter... but the trade off is a cooked engine with holes in the pistons. RW modern aircraft are designed for LOP these days. I'd say the "standard" is 20^ LOP ***AT CRUSE***, and 75% power. As pointed out by CoolP, RW aircraft will have this all spelled out in the POH.

 

The good news is, all the major engine manufactures are developing computer controlled fuel injection with modern ignition systems. The one I saw at Lycoming this past summer is sweet. One day, this will all be laughed at... and future pilots will think we were crazy trying to manually control AFR.