FSX-MS FSX Turboprop ITT Comparison

[Les Parson 99]

Here is the engine mod topic

 

http://www.avsim.com/topic/461589-pc12-overhaul-mod-v10-and-n594wa-repaint-released/

 

I'd ask him, he's been away from updating the mod for a few months but said hed be back. Couldn't hurt to ask. I don't own the C90 but have their C200 and would like the mod for that too. But it looks like a lot of work.

 

Thanks, I sent him an email a few hours ago.

[autogyro 18]

Hi guys just came across this thread thanks to LDP's email.

 

Ostensibly yes it can be done to any and all aircraft; all I did was to brute force it in a way.

 

The current turboprop simulation in the base FSX game is all sorts of wrong for the PT6A engines.

 

No doubt your professional modellers from RealAir and Milviz will do a bang up job with ITT modelling.

 

Unfortunately these days I'm short on time so I'm hesitant to make promises I can't keep - although I wish I had the time to help everyone.

 

The current ITT output is mostly affected by the torque output only and drops too much with altitude. What I did in the PC12 is to:

 

Determine what the realistic ITT values are in relation to various flight regimes based on POH.

 

Correct ITT values with altitude at ISA conditions. In retrospect I should not have made the ITT values a function of altitude but air pressure or inverse air pressure as it gave me more work to do later on.

 

Correct ITT values with temperature for a fixed altitude based on POH.

 

Correct ITT vs torque. I found it was not sensitive enough to torque changes at various altitudes and temperatures.

 

Correct fuel use to be an approximate average to real world use at near cruising conditions based on POH.

 

The corrections are basic maths, you just take what you output and you write formulae to correct it and set it as close to a trend as you can.

 

Cleverer people than I would write better functions and use better input parameters. A better starting point than the FSX ITT model would also help.

 

In the end though, my ######ised model does its job well enough to be a more realistic approximation of the PC12 torque and ITT relationship than anything the base gauge would output or what you could do with the .air file, and I'd argue is the most realistic PC12 simulation available at the moment.

 

As for the C90, the theory would be the same, if anybody wants to give it a go. I'm more than happy to help but I can't devote that much time (or it would take me months to do it) to do it myself anymore.

[taguilo 33]

The engine (and ITT) control system isn't even IN the alpha that was put out.

 

Hence the reason it's called ALPHA... 

 

We're working hard in close conjunction with Tomas and he's got THAT end totally covered.

 

Worry not, it will do as it's supposed to do.

 

Colin is right, the incoming engine system for the KA 350i models ITT in every aspect possible, bypassing FSX limitations.

 

BTW, there is a simple test that can be done in a King Air turboprop to detect whether engine parameters are right:

 

Position the aircraft at El Alto Airport, La Paz, Bolivia (13000+ ft.), with 28 °C temperature, no head winds, at or near MTOW, and try to take off and maintain a climb attitude. 

 

If the aircraft fails the test, engine parameters are well modeled; otherwise they are not.

 

Tom

[Les Parson 99]

Hi guys just came across this thread thanks to LDP's email.

 

Ostensibly yes it can be done to any and all aircraft; all I did was to brute force it in a way.

 

The current turboprop simulation in the base FSX game is all sorts of wrong for the PT6A engines.

 

No doubt your professional modellers from RealAir and Milviz will do a bang up job with ITT modelling.

 

Unfortunately these days I'm short on time so I'm hesitant to make promises I can't keep - although I wish I had the time to help everyone.

 

The current ITT output is mostly affected by the torque output only and drops too much with altitude. What I did in the PC12 is to:

 

Determine what the realistic ITT values are in relation to various flight regimes based on POH.

 

Correct ITT values with altitude at ISA conditions. In retrospect I should not have made the ITT values a function of altitude but air pressure or inverse air pressure as it gave me more work to do later on.

 

Correct ITT values with temperature for a fixed altitude based on POH.

 

Correct ITT vs torque. I found it was not sensitive enough to torque changes at various altitudes and temperatures.

 

Correct fuel use to be an approximate average to real world use at near cruising conditions based on POH.

 

The corrections are basic maths, you just take what you output and you write formulae to correct it and set it as close to a trend as you can.

 

Cleverer people than I would write better functions and use better input parameters. A better starting point than the FSX ITT model would also help.

 

In the end though, my ######ised model does its job well enough to be a more realistic approximation of the PC12 torque and ITT relationship than anything the base gauge would output or what you could do with the .air file, and I'd argue is the most realistic PC12 simulation available at the moment.

 

As for the C90, the theory would be the same, if anybody wants to give it a go. I'm more than happy to help but I can't devote that much time (or it would take me months to do it) to do it myself anymore.

I have the time and the C90 POH for the -21 engine. However, I don't have the expertise nor the Carenado PC-12. Thanks for all this valuable info. I will PM you.

[robert young 2,897]

You can make ITT do almost anything you wish, if you code some xml or C++ gauges which over-ride the default behaviour. But all that is doing is creating something artificial on top of something else that is also artificial. By its very nature, everything in simulation is about hacking other stuff that is also hacked. I think there are more important things to be concerned about first. For example, lots of sim products have gauges which read more or less completely "correct" but that doesn't necessarily make the feel of what you are flying any more convincing. 

 

I remember a very well known developer hacking a big piston tail dragger aircraft he was creating, and to get the steering to work better on the ground he had to create a dummy nosewheel 20 feet in front of the aircraft, unseen, so the tail behaved reasonably to his satisfaction, 40 feet behind his hacked notional landing gear. Essentially this model was in fact steering from the front while appearing to steer from the tail wheel. It did the trick and no-one was the wiser for it. This kind of hacking is really quite routine. There's nothing much wrong with it because all it does is try to create an impression that is satisfying for the end user. As long as you know that very little of this stuff is more than an illusion layered upon another illusion. 

 

It's well known that turboprop modelling in FSX is not the greatest achievement, so all sorts of tricks have to be conjured to create a better impression. It is not proper modelling in the sense that some might feel is happening. It is just finding tricks to negotiate a way around a flawed core system. I have no doubt that exactly the same things happen with the most expensive motion sims too. In fact I know that is the case because motion sim designers have exactly the same hurdles to clear.