After Last Accusim Core update the EGT is very high

[Flocat]

After Last Accusim Core update the EGT is very high, it is normal?
when i lean only a minimum at 3000ft, the EGT goes very high, before this update it was not so.
it this normal?

Greetings from Germany!!

[Tug002]

I also noticed the same thing and was wondering the same. I find it hard to keep the temp under 1300 F.

Keep smiling
Tug

[taildraggin68]

I will add to this...fresh install after computer reboot, FSX Boxed, Fresh install of 172, updated with updater to latest update, very high egt values. I don't recall them being that high before.

[Tug002]

I will add to this...fresh install after computer reboot, FSX Boxed, Fresh install of 172, updated with updater to latest update, very high egt values. I don't recall them being that high before.

Thanks taildraggin68, it is good to know that we are not the only ones.

Keep smiling
Tug

[Scott - A2A]

The EGT was re-designed in a recent update. I just pulled up our EGT test flights, done at both 4,000 and 12,500 at different power settings and mixture, and the Accu-Sim 172 is spot on.

Simulating EGT is one of the most illusive animals, but what you are seeing now is something far and away beyond what any simulator has even approached.

You will notice, for example, as you climb EGT will be on the low side of the scale, and slowly decreasing as you gain altitude. When you lean, it will move towards the top 3/4 of the scale.

Also, while the actual number / temp of Cylinder Head Temperature (CHT) is very important, EGT isn't. EGT is used for two things only - leaning and troubleshooting. 1300, 1400, 1500 deg = meaningless. Cylinders are usually 100 degrees apart, where the probe is placed on the exhaust makes a diff, etc. This is why many EGT gauges don't even include the actual temps, just dashes - you are only looking for movement based on your mixture settings, to make more precise mixture.

Either way, your Accu-Sim 172 is in every way we can determine, performing precisely like the 172's we fly.

Scott.

[Dooga]

Thanks for the update Scott - I also have observed this, and in my case EGT is not at 3/4 of the scale but actually scratching the upper scale limit when cruising and leaning properly - definitely higher than in our club's IO - 172, but to be fair that gauge has gone bust completely a while ago so no telling how accurate it was before that...

[Tug002]

Thanks for the reply Scott. I usually fly at low throttle settings and rarely does the EGT go above half way so I guess everything is good. I was just currious about the change.

Keep smiling
Tug

[AKar]

Good post by Scott - I like reading his writings and especially videos as they give a peek into the stuff that gets more attention in simulation development at any given time.

Each time I read about high EGT values or difficulties in keeping the value under some figure, I can't keep my fingers from writing: STOP! You don't know your EGT value in the modeled Cessna! These gauges are not calibrated to display specific, absolute figures and therefore lack any scale except a relative one without numbers. You don't have that tool tip in real life, and individual instruments may behave differently, making comparisons meaningless. Let us instead put it this way: if you respect the limits (or even exceed many of them that are not 'hard' ones technically), in a naturally aspirated airplane engine, there is no harm caused by high EGT values. The EGT is not limited in any way. In turbocharged engines it can be, but they typically have (or should have!) better instrumentation.

When you cruise, even at low power, the gauge can show some high deflection, but that is not a problem. Instead, for economy cruise as it is recommended by engine manufacturers you should fly at the highest EGT value you can possibly get for the given power setting! That is leaning to peak EGT. And it is actually better to the engine's health than being shy and leaving the EGT short from the peak.

-Esa

[Piper_EEWL]

Good post by Scott - I like reading his writings and especially videos as they give a peek into the stuff that gets more attention in simulation development at any given time.

Each time I read about high EGT values or difficulties in keeping the value under some figure, I can't keep my fingers from writing: STOP! You don't know your EGT value in the modeled Cessna! These gauges are not calibrated to display specific, absolute figures and therefore lack any scale except a relative one without numbers. You don't have that tool tip in real life, and individual instruments may behave differently, making comparisons meaningless. Let us instead put it this way: if you respect the limits (or even exceed many of them that are not 'hard' ones technically), in a naturally aspirated airplane engine, there is no harm caused by high EGT values. The EGT is not limited in any way. In turbocharged engines it can be, but they typically have (or should have!) better instrumentation.

When you cruise, even at low power, the gauge can show some high deflection, but that is not a problem. Instead, for economy cruise as it is recommended by engine manufacturers you should fly at the highest EGT value you can possibly get for the given power setting! That is leaning to peak EGT. And it is actually better to the engine's health than being shy and leaving the EGT short from the peak.

-Esa

I agree with you! It's not like you lean to a certain temp in real aircraft because you don't have the gauges to do so. I fly a Piper Super Cub that doesn't even have a EGT gauge. So you just lean by hearing. Pull the mixture back till the engine starts sounding different (like loosing power) and then just add the mixture back in till it runs smoothly again.

And thank you for the explanation Scott!

[Tug002]

Good post by Scott - I like reading his writings and especially videos as they give a peek into the stuff that gets more attention in simulation development at any given time.

Each time I read about high EGT values or difficulties in keeping the value under some figure, I can't keep my fingers from writing: STOP! You don't know your EGT value in the modeled Cessna! These gauges are not calibrated to display specific, absolute figures and therefore lack any scale except a relative one without numbers. You don't have that tool tip in real life, and individual instruments may behave differently, making comparisons meaningless. Let us instead put it this way: if you respect the limits (or even exceed many of them that are not 'hard' ones technically), in a naturally aspirated airplane engine, there is no harm caused by high EGT values. The EGT is not limited in any way. In turbocharged engines it can be, but they typically have (or should have!) better instrumentation.

When you cruise, even at low power, the gauge can show some high deflection, but that is not a problem. Instead, for economy cruise as it is recommended by engine manufacturers you should fly at the highest EGT value you can possibly get for the given power setting! That is leaning to peak EGT. And it is actually better to the engine's health than being shy and leaving the EGT short from the peak.

-Esa

I agree with you! It's not like you lean to a certain temp in real aircraft because you don't have the gauges to do so. I fly a Piper Super Cub that doesn't even have a EGT gauge. So you just lean by hearing. Pull the mixture back till the engine starts sounding different (like loosing power) and then just add the mixture back in till it runs smoothly again.

And thank you for the explanation Scott!

Thank you for your input as it has been very helpfull. All of the aircraft that I have ever been in or have had the oppourtunity to fly in the past had only the nessary gauges for flight and did not include and EGT so I was currious as to the operation of the gauge. You have been very helpfull with the question. As always the A2A fourm is the best source for great information. Not being around or flying in any aircraft for over 30 years and now flying A2A's aircraft has raised many questions for me that are usually answered promptly in the fourms, thanks again

Keep smiling
Tug

[Caldemeyn]

A question, why does EGT rise when levelling off and closing the throttle some amount ? (No mixture changes). One would think that with lower power setting and growing speed it would come down ?

[Oracle427]

At full throttle the engine is being fed a lot of extra fuel to keep things cool. When the throttle is pulled back the mixture is leaned causing a rise in the EGT.

This is exactly like the real aircraft. Climbing at partial power in a 172 will result in a higher EGT with a constant mixture setting.

[Nick - A2A]

Oracle - I was just about to post much the same thing, but Mike Busch can explain it better than me:

High CHTs often indicate that the engine is under excessive stress, which is why it's so important to limit CHTs to a tolerable value ... By contrast, high EGTs do not indicate that the engine is under excessive stress, but simply that a lot of energy from the fuel is being wasted out the exhaust pipe rather than being extracted in the form of mechanical energy.

His 'SavvyAnalysis' article: EGT Myths Debunked is probably worth a read Caldemeyn.

Cheers,
Nick

Edit: here's another excellent article on Mike Busch's site: Understanding CHT and EGT.

[Caldemeyn]

Thanks guys, suspected something of the sort, but its always good to get a confirmation.

The articles are great, will read for sure.