Inaccurate Mixture Behavior on Turbocharged Piston Engines

I’m glad I stumbled across this topic. I’m grabbing the files now. This has irked me ever since I got the Turbo Arrow’s and Seneca. Asobo really needs to look into this as is a rather large oversight of a core system on how the engines work.

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This topic has definitely been unnoticed by so many. This is a very important issue.

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Hello WxMarc,

We investigated in this, but the issue raised is based on a feature that doesn’t yet exist on the SIM. Right now, we don’t have default Turbocharged aircraft and changing the setting on the Cfg file can’t result in activating it.

The Turbocharge line in the Cfg file is an heritage of FSX, this is why this line is displayed.

Instead of a bug, this thread should be turned into a request on the wishlist section to add a Turbocharged feature for specific planes.

I’m letting you read the information above before doing any change on the thread.

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Thank you for investigating and providing feedback. I’m a bit confused, though. The turbocharged line in the engines.cfg file definitely has an effect. As such, I’m not sure what you mean by saying that changing the setting “can’t result in activating it.” If turbocharged = 0 in the cfg file, the engine will lose power with altitude like a naturally-aspirated engine should, and no adjustment to the mixture will restore the engine to full sea-level power. On the other hand, if turbocharged = 1, the engine is capable of producing full sea-level power as long as the mixture is adjusted. This is not correct behavior (the mixture should not require adjustment to maintain power in a turbocharged engine), but it is different than the default behavior when turbocharged = 0. To me, this seems like a bug rather than a requested new feature.

If the team would prefer to scrap the old FSX turbocharger logic and start from scratch, I would support making this a wishlist item, but I just want to clarify that the existing logic does have an effect, and the data I’ve reported in this thread documents the bug in the existing logic.

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Should we take this statement to mean that turbocharged aircraft are not supported by MSFS? That is, 3rd party devs should write custom code for the engine logic?

Anyway, isn’t the PC-6 coming to MSFS as part of the GOTY edition? As this has a turbocharged engine, does that mean that turbochargers are supported from SU7/GOTY onwards? :crossed_fingers:

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The PC-6 is a turboprop (gas turbine engine with propeller), not a turbocharged piston. So, the PC-6 would not be affected by the turbocharger logic issue documented in this thread.

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Sorry, my bad.

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For those that are unsure of the difference between turbocharged and a turbo prop - a good video on the PT6A reverse flow dual shaft free turbine engine common in turbo prop aircraft like the PC6.

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In addition to WxMarc’s response, I would note that your third-party partners are under the impression that the turbocharged=1 setting has an effect, since it’s used on Marketplace aircraft such as the Carenado Seneca V (among others). If the official stance of the development team is that the setting does nothing and is unsupported, this should be communicated to the third-party partners more clearly so they know not to use it.

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eh, well the GOTY edition has the p51… that turbocharged so you DO now have default turbocharged piston aircraft… time to revisit this.

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Bumping this for appearance.

Asobo, you now have two default aircraft in the sim, the T6 Texan and P51 which are TS engines, as well as multiple other Turbo aircraft coming in as payware (To my knowledge, C182T, M20R, C337 (unsure of exact variant some were TSIO engines), PA34T, PA28R Turbo, C414A, and many others soon to come) which are all flawed on the basic principle of their operation.

In my eyes this is no longer an ignorable system deficiency and needs to be addressed for the overall well-being of the sim. Asobo, do you really expect us to be at cruise altitude with our mixture levers teetering between flooding the engine, normal operation, and fuel starvation?

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BIG BUMB!

This is important ASOSBO and MS! We count on you here!!!

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Would love to see this get the “bug logged” tag, at least. Personally I’m shocked this issue isn’t getting more traction, but then again, I imagine the number of people who regularly fly turbocharged aircraft in the sim and care about whether or not they work properly is a single digit percentage.

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I think they would care once they realize when they’re out of mixture lever to pull back on that something must not be right…

True - you end up being a hairline off idle cutoff sometimes.

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Still an issue Asobo - though SU8 was all about bug fixes? Can we please get an official response here?

Hi @WxMarc, with the imminent release of the turbocharged C414, is there an easy way to make the mod work with a twin or would that require significant changes?

Thanks!

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A note about mixture and turbochargers here.

The easiest way to think about an internal combustion engine is to remember it is simply a big pump, driven by controlled explosions. To manage those explosions, there are two primary controls: throttle and mixture. Throttle controls airflow into the plenum (throttle body or manifold); mixture controls the amount of fuel available to combine with that charge of air. Manipulating those two controls allows the pilot to manage the air/fuel ratio.

Adding a turbocharger (or a supercharger as equipped on a P-51 or a DC-6) allows compensation for the loss of atmospheric density as altitude is increased. Airflow is still managed with the throttle, but the turbocharger allows the pilot to maintain a sea level (or greater) amount of air entering the plenum (throttle body or manifold) at greater altitudes.

There are primarily two methods of utilizing turbochargers on an internal combustion engine: manual control of the wastegate, and automated control of the wastegate. The Just Flight Turbo Arrow in the sim is an example of a manually controlled method; the Carenado C182T is an example of automated control (aka turbo-normalized) method.

In either case, since airflow is - more or less - constant with a turbocharged powerplant the mixture control should be a non-factor in engine management up to the powerplant’s critical altitude.

There’s more (much more) that could be discussed, but this post is an attempt to support (and perhaps expand) on the OP’s topic and not wander too far off.

It is interesting to note the following from the manual for the upcoming Flysimware C414… maybe this is affirmation that the mixture behavior on turbocharged piston engines is flawed?

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Yes, I made a version of the mod for the Carenado Seneca V which is a twin-engine turbocharged airplane. I have been eagerly anticipating the Cessna 414. I’ll be working on creating a version of the mod for that airplane. I expect to be able to update the mod by the end of the day Monday (US Central Time). Keep an eye on the mod thread here for the update:

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That’s great news. You’re the best, thanks so much!

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