Engine damage

[Brett_Henderson]

More thoughts...

How about an XML document (cumulative_wear.xml) in the panel folder, that serves no purpose other than to store a number (cumulative wear).

Then, the XML files that keep track of wear per session, could also take the number from cumulative_wear.xml.. add to it when conditions warrant, and initiate a failure when IT reaches a certain value..

I.E. .. When CHT is exceded, not only does the session specific "count-down" begin.. a loop that retrieves 'cumulative wear', adds to it, compares it, and re-writes the XML file with the new value, so that the long-term wear is stored.

 

[Aviator273]

WOW!!!

I gave it a try with fsx and the default Cessna 172 now. This gauges are the greatest improvement for the aircrafts ever. Good work. The only think leading to a crash here is the flaps overspeed. Dunno if it was my mistake or not. Since there's another plane in my library using a sound-gauge with the same description I didn't want to overwrite the file and just left it besides. May it be possible that there's some conflikt due to the gauge beeing both in the gauge folder and the panel/realengine folder? If these files are different to each other so that it's just loading a completly wrong gauge from my gauge folder, may this lead to the problem?

Greetings.

 

[teson1]

Brett,
good to hear that you could make the gauges do what you want.
Just one point you may want to look out for. If you want to follow two engines at the same time you may have to give some L: variables a unique name, otherwise the gauges for eng 1 and eng2 may use some of the same L: values to store data (overwrite), and probably only one engine will ever fail in that case.

I had actually considered to include damage to several engines for multiengine aircraft.
While that would have been quite easy, I shied away for the time being, for fear of (unavoidable) lengthy troubbleshooting sessions. I was addressing fundamental changes to working modules very carefully at that time. I feel XML is a bitch in penalising the slightest error in syntax... Maybe if ever for a v2.

And if you find a way to write and read from an ini file - that would be NICE!
Good luck, and let me know if you find a way.
With a C gauge it must be possible (to read at least - Doug Dawson's sound gauge does). But C is currently outside of my domain of expertise, or rather my domain at all...

Hi Aviator,
glad to hear you like it. Thanks.
AFAIK having Doug Dawson's sound gauge in the gauges and panel folder at the same time causes no conflict. AFAIK FS first looks in the panel folder for the gauge specified in the panel.cfg, and only if it does not find it there, in the gauge folder.
Also, Doug's dsd_xml_sound3.gau gauge is unchanged, so if you have installed the same version already, then you can also just delete the one in the panel.cfg.
The RealEngine specific file is actually dsd_xml_sound3_RealEngine_v05.ini, which defines the sound files to play, and has to be in the gauges folder to be found by dsd_xml_sound3.gau (as specified in the panel.cfg).

Pls report back if you have further problems with crashes due to the flaps failure or other modules. I may have to look into that. No idea off of my head how the XML gauges would cause a (computer or FS) crash. Thanks.

Regards.

 

[Brett_Henderson]

I dowloaded Visual C++ .. will start playing with it... but I've got my hands full learning XML..

What I did literally; was to copy all the modules.. renamed them all RE2-XXXXXXXX.xml...deleted the status panel gauge, and gear/flap stuff.. added them to the panel.cfg .. .. and then changed every '1' reference, to a '2' reference, inside each module.

I get both or either engine to fail..

What you've got here, is a really nice, efficient, elegant add-on. I know that I can read/alter/write to simple text file, for the cumulative damage with C++... It'll just take me time to get comfy with this editor/compiler..

 

[sc7500]

Hmmm...

...Per cubic inch, the above mentioned R2800 CB 16 is a deal! About $3,700/cyl or $25/cu inch. My Super cub engine was $6,240/cylinder or $78 per cu inch...

And people still think I'm crazy to build race engines for Sportsman dragsters...

For just under $10K I can make close to 1,000HP and move a 1400# car 0 to 100 in under 1.2 seconds...

But then, it's NOT flying like I'd prefer - just REAL close to the ground !
SC

 

[fliger747]

I any single engine airplane that haulls me and mine about, reliability is vital at the expense of volumetric efficency. Specific fuel consumption is also pretty important, especially at $ 4.75 or so a gallon for Av Gas.

Most of the GA engines are pretty old (simple) technology dating from the 40's. Modern materials and mfg methods have increased the quality. Some new non turbine technologies have been creeping in, such as the Thielert turbo diesel.

Of course when I go to work I have something like 250,000 hp in my right hand.....

Cheers: T

 

[Brett_Henderson]

UPDATE:

I've been running this (two-engine modification), pretty hard.. after a few more tweaks to the model's air-file (mostly around CHT).. I've got it working near perfectly on a non-turbocharged mod of Carenado's Seneca (basically a Seneca I ) ...

The key is to get the model's CHT to respond more realistically..and get it to where cowl-flaps and airspeed have realistic impacts on CHT..

 

[teson1]

Interesting.
Would you mind to share how you have done that?
Is it trial and error, or is there a systematic approach?
A hammering the CHT in place for dummies guide??

 

[Brett_Henderson]

Interesting.
Would you mind to share how you have done that?
Is it trial and error, or is there a systematic approach?
A hammering the CHT in place for dummies guide??

Just open the air file, with AirEd... You'll see an entry for CHT.. There are four parameters.. They effect the overall scale, the maximum, the cooling, and the response rate..

I'll post the numbers I've used, when I'm on my simming computer..

 

[fliger747]

There are some serious problems with the way that FS derives CHT. It appears that it mostly relies on RPM, almost not at all on MP, somewhat on airspeed and cowl flap position. This probably dates back to the beginnings of FS with simple fixed pitch engine/prop combo's

An example of where such problems can crop up is on approach when the RPM's will be advanced for a possible go around, power is up slightly due to flap/gear drag and MP is low. In a real plane the CHT's will be fairly low, in FS they will go up. This can trigger engine malfunction parameters if they are linked to some real world CHT limit, if the scale and other values produce good values during the other stages of flight.

A gauge wizard is required to wave his wand to compensate for the basic system....

T

 

[Brett_Henderson]

I've gotten some pretty good results.. all phases of flight, with these numbers in a Carenado Seneca (will work well for any 200-300 HP piston prop, if tweaked):

 

[teson1]

Brett, thanks for the details. I'll have a try with them.

I'd quickly abandoned any focus on CHT as tests of normal CHT response on different acft gave unconsistent and unrealistic results.

But who knows, it may be worth a second look (though I have the feeling that I'll probably still run into the problems Tom has pointed out).

Thanks!

Gunter

 

[teson1]

That brings me to a larger question relating to real-world CHT importance.
(in particular in small GA piston engine planes)

- Under which conditions can/does CHT actually exceed temperature limitations in real-worls use???

Does CHT ever exceed limitations if the engine is healthy and maximum recommended operating conditions are respected? (i.e., are the engine designed so that limitations are normally not exceeded?)

During a normal flight, does the pilot have to continuously monitor CHT and regularly take action to keep CHT within limits?
Or is only exceptionally active action required?
Or are limitations only approached/exceeded if something is really wrong with the engine?

What are the conditions where overheating of the engine is commonly a concern for real pilots?

During what phases of the flight is overheating most likely?

Are there particular aircraft known to be more prone to overheating than other? Underdimensioned cooling systems?
Is one type of airplane more prone to overheating than another, e.g. GA vs high powered warbirds?

I feel this could be a huge topic due to all the different variables that may play a role, but I'm eager to hear any input.

Thanks!

Gunter

(And just a note re the release of RealEngine in case anybody is interested - still tweaking, so will take a little more than "a day or two" I've mentioned below.)

 

[stansdds]

There are some real pilots who frequent the boards, you might want to post a call for their help in the FSX and FS2004 forums and point them to this thread. I know Ken Stallings is a very experienced pilot.

 

[fliger747]

CHT has a number of uses, that and EGT. (1) you want the cylinders to warm enough before takeoff as a quick heating will cause the pistons to expand faster than the cylinders with predictible "issues". (2) you don't want the engine to cool too quickly with power reduction as cylinder cracking can occur. (3) CHT is used to adjust the cowl flaps and can be used to some extent to adjust mixture at altitude.

With the DC2 project we went around and around with CHT issues as we were attempting to replicate the actual climb and cruise values, requiring operation of the engines by the book. Where this fell down was in the low speed high RPM of approach where the engines would want to overheat since FS ignores manifold pressure. CHT was used to trigger engine malfunctions. The only cure is to use gauge technology to tie MP or developed HP to a non visible cowl flap (the DC2 had no cowl flaps) or bias the CHT reading in a similar manner.

All of this only becomes an issue in an engine that can approach the cooling limits.

Cheers: T

 

[teson1]

Stan, been there, done that (just now) - thanks for the rec!
And I think we have at least Brett and fliger as active pilots in here.

 

[teson1]

... and I see fliger was mighty fast with a response- Thanks!

All of this only becomes an issue in an engine that can approach the cooling limits

Does that mean that many small GA planes might not even be able to exceed the temperature limitations, and that actually no particular action is needed to keep the CHT within limits?

Could you get the CHT on your Cub easily over the limit during a normal flight? (Does the Cub even have a CHT gauge??)
And how about if you pushed it?

(Your points (1) and (2) give interesting opportunity for including in a damage module once CHT behaves realistically )

 

[Brett_Henderson]

I flew a Cardinal-RG, where you'd have to TRY to make it overheat. I started thinking that it had cowl-flaps on it simply for training (it's a great complex trainer). The only time CHT got near red, was on steep, slow, long climbs.

Then there was this 182, where you didn't even want to start it, until you knew you could be up and flying soon.

I've flown a 310 that didn't have cowl-flaps at all.

There was a Mooney M20J, that had CHT gauges that acted like you'd think they would.

The keys there are, gauges and think. Older gauges aren't always accurate..

ANYway.. the only universal parameter here, is to just use them (cowl flaps) logically.. Apply tham as called for, and mostly to manage temp changes so that they aren't dramatic.

 

[pilottj]

high power settings and high angle of attack/climb will give you a warm CHT. Taking off in an area with rugged terrain around forcing you to maintain high climb rates and power settings will make you keep a close eye on the engine temp, especially in the warmer summer months. The A2A P-47 simulates this well. Take off on a warm day and climb at Vx and watch your temps stay warm even with cowl flaps open. When I flew for real, I would always prefer to cruise climb whenever possible. The same conditions can occur in your car, if you are driving up a hill in 2nd or 3rd gear, higher RPMs with a slower speed, less airflow through the engine...warmer engine.

Cheers
TJ

 

[azflyboy]

... and I see fliger was mighty fast with a response- Thanks!

Does that mean that many small GA planes might not even be able to exceed the temperature limitations, and that actually no particular action is needed to keep the CHT within limits?

Many GA aircraft are pretty resistant to overheating unless the pilot really abuses the engine. Aircraft are likely to operate in a wide range of temperatures, so most piston aircraft are designed to keep the engine cool under "worst case" circumstances, and therefore have excess cooling capacity at lower temperatures.

That said, some aircraft have cowling designs that cause engine temperatures to skyrocket without careful pilot monitoring, but those tend to be high performance aircraft with relatively tempermental turbocharged engines.

I work as a flight instructor in North Dakota and got my private certificate in Arizona, so I've had the chance to fly in temperatures ranging from +100F to -40F, and to see how aircraft engines react to those climates.

In Arizona summers, engine temperatures (all I had was an oil temperature) tended to run a bit warm, but they never got outside of the green arc in flight, even during prolonged full power climbs. Engine temperatures would tend to creep up during prolonged ground operations, but again, I never encountered a situation where the oil temp moved out of the normal range.

In North Dakota, we run into problems with the aircraft (Piper Warriors and Cessna 172's) actually having too much cooling in the winter. When the temperature starts getting close to freezing, the aircraft are fitted with plastic baffles that either restrict airflow into the cowling (for the Cessnas) or block airflow past the oil cooler (for the Warriors).

Without those baffles in place, the engines (which are air cooled) can be literally incapable of warming up to normal operating temperatures, since there's just too much cooling of the engine taking place.

During really cold weather (-30 and below), the engines are clearly unhappy about having to work in those temperatures. Even with the winterization plates installed, it can take 10 minutes for the engine oil to warm up to the point where takeoff is allowed, and anything but smooth movements of the throttle when adding power results in either backfiring and hesitating or (occasionally) the engine simply quitting.