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V1.6.4 First Flight & a Couple of Issues


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Hi guys,

Great flight in the new 340 just now, but still a couple of things I hope get fixed before finalising V1.x.x development:

 - Engines still experience a very rapid ITT rise and slight over-temp (not enough for the OT lights to illuminate) when moving the CLs from Start, through to Min and on to Max.

- The trim in AP is still a problem as I previously reported. It gets stuck in a Pitch Up position and neither the DataRef nor Trim indicator change at all when AP is engaged. When AP is disengaged you get a sudden Nose Up rotation (MJRHealth has also previously reported it on V1.6.3). Works fine out of AP; aircraft is able to be trimmed.

On a good note, the ILS issue I previously reported now works a treat - thanks.

Cheers.

Log.txt

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2 hours ago, Cam said:

Hi guys,

Great flight in the new 340 just now, but still a couple of things I hope get fixed before finalising V1.x.x development:

 - Engines still experience a very rapid ITT rise and slight over-temp (not enough for the OT lights to illuminate) when moving the CLs from Start, through to Min and on to Max.

- The trim in AP is still a problem as I previously reported. It gets stuck in a Pitch Up position and neither the DataRef nor Trim indicator change at all when AP is engaged. When AP is disengaged you get a sudden Nose Up rotation (MJRHealth has also previously reported it on V1.6.3). Works fine out of AP; aircraft is able to be trimmed.

On a good note, the ILS issue I previously reported now works a treat - thanks.

Cheers.

Log.txt 163.66 kB · 0 downloads

Have you thought, just for a second, that a momentarily over-temp might be a normal, realistic behavior? And even in the flight manual there might be a section that states the time limitations and temperature limitations that are above the indicated maximums during the engine start?

It's not a slow, lazy PT6. It's a geared direct drive turboprop. Things happen fast in it, and get to normal fast as well.

Edited by B-7
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7 minutes ago, B-7 said:

And even in the flight manual there

It's not, but very common in XP.
I'd almost suggest its Laminars engine model potentially.

Quote

It's not a slow, lazy PT6. It's a geared direct drive turboprop.

CT7 is a free turbine

Edited by N1K
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Nick is right... Austin models turboprop behavior based mostly on a PT-6 because that is what he flies.  We have overridden a LOT of the engine behavior but it's a balancing act.  If we adjust the fuel flow to "fix" the ITT swings then the engines will respond too slowly.  I think we have found a good balance for now.

Edited by JGregory
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This rapid ITT rise has always been present when moving from Start to MIN and from the videos I have seen it occurs in the real plane, although not as much.

But I have noticed that the Torque,  ITT temp and engine RPM seem to be very twitch when you move the power levers around ground and flight idle positions.

My elevator trim is still not moving either when the autopilot is connected.

Also I experienced my glide slope bars missing again. Not sure what I did but will see if I can repeat it.

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32 minutes ago, JGregory said:

Nick is right... Austin models turboprop behavior based mostly on a PT-6 because that is what he flies.  We have overridden a LOT of the engine behavior but it's a balancing act.  If we adjust the fuel flow to "fix" the ITT swings then the engines will respond too slowly.  I think we have found a good balance for now.

Curious, did you consider a fully custom engine modeling, like Thranda did for example? I know that’s something more like for v2, but I can imagine it could give you less dependency on Austin’s ideas from his DIY engine control.

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The Saab basically overrides all engine inputs, so for all intents and purposes it is a custom engine model.  But we are limited in how much control we have over the output.  I don't think we will be writing our own engine model... that would present far too many compatibility issues in the future. 

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Hi JGregory,

I reported what appears to be a bug with the pitch trim (AP engaged) in both the last version and the latest version but have not seen any feedback from you guys (MJRHealth confirmed it). 
 

Have you been able to replicate it yet and, if so, will it be rectified in a V1.x.x update. 
 

Cheers

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1 hour ago, Cam said:

Hi JGregory,

I reported what appears to be a bug with the pitch trim (AP engaged) in both the last version and the latest version but have not seen any feedback from you guys (MJRHealth confirmed it). 
 

Have you been able to replicate it yet and, if so, will it be rectified in a V1.x.x update. 
 

Cheers

I have not seen this happen in the test flights I have done.  You and MJRhealth are the only ones reporting this as an issue.  At this time I don't know if there is a problem with the Saab or a problem on your end.  I will continue to test and see what I can find, if anything.

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1 hour ago, JGregory said:

I have not seen this happen in the test flights I have done.  You and MJRhealth are the only ones reporting this as an issue.  At this time I don't know if there is a problem with the Saab or a problem on your end.  I will continue to test and see what I can find, if anything.

not sure @Cam and I are quiet seeing the same thing. I did have a couple of flights where pitch trim was up top, put that down to CG which i moved. Dont recall pitch trim not moving with AP on, but on last landing did get a sudden nose up on AP disconnect, though pitch trim looks ok. Get a flight in today see what happens and try get some screen shots.

From last flight mentioned

LES_Saab_Trim.jpg

Edited by mjrhealth
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3 hours ago, JGregory said:

I have not seen this happen in the test flights I have done.  You and MJRhealth are the only ones reporting this as an issue.  At this time I don't know if there is a problem with the Saab or a problem on your end.  I will continue to test and see what I can find, if anything.

Could it be that I have pitch trim enabled on both my yoke rocker switch and the trim wheel of my throttle quadrant. I’ll disconnect the trim wheel and see what happens tonight. 

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1 hour ago, Cam said:

Could it be that I have pitch trim enabled on both my yoke rocker switch and the trim wheel of my throttle quadrant. I’ll disconnect the trim wheel and see what happens tonight. 

Be surprised it makes any diff as they are both digital inputs.

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5 hours ago, mjrhealth said:

Be surprised it makes any diff as they are both digital inputs.

Yep - you are right, just confirmed it. I have just posted a new topic on this that you might like to read and see if you can duplicate it.

Cheers

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8 hours ago, mjrhealth said:

not sure @Cam and I are quiet seeing the same thing. I did have a couple of flights where pitch trim was up top, put that down to CG which i moved. Dont recall pitch trim not moving with AP on, but on last landing did get a sudden nose up on AP disconnect, though pitch trim looks ok. Get a flight in today see what happens and try get some screen shots.

 

 

That is intresting. I'm flying very mixed loads at FSE (PAX, mixed PAX and cargo and cargo only) and have never thought moving CG. Most planes I've flown (MD-80, 757) have had CG calculator with load manager software etc. Now is this something you would normally consider with Saab? The problem is that there is no load manager nor load sheet so we don't know where they sit and how much luggage they have.

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3 hours ago, SupraJari said:

That is intresting. I'm flying very mixed loads at FSE (PAX, mixed PAX and cargo and cargo only) and have never thought moving CG. Most planes I've flown (MD-80, 757) have had CG calculator with load manager software etc. Now is this something you would normally consider with Saab? The problem is that there is no load manager nor load sheet so we don't know where they sit and how much luggage they have.

This may be what you want...  

 

Edited by JGregory
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My autopilot works well.

 

During the flights, it was noticed:

Maximum takeoff weight.

Fig. 1 In the climb and using the CTOT system, the engine speed goes beyond the limits. But the thrust and vertical climb speed are good.

1.jpg

Edited by Candid
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Fig. 2 I turned off the СTOT and reduced the thrust so that the engine speed was within the permissible range. The thrust and the vertical rate of climb fell. And this is in winter, when you can get maximum power from the engine!

Note, that there is still a long way to go to a practical ceiling. Dear Authors! See what can be done here?

2.jpg

Edited by Candid
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Fig. 3 I moved the ore all the way forward and got an increase in thrust and vertical speed, which is more like the truth. BUT!!! Engine speed is out of range !! The instructions describe little about the principles of СTOT operation. And in the example it is generally recommended not to touch the thrust levers after takeoff. How can I fly with such parameters?

3.jpg

Edited by Candid
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For the sake of such an application do I need to buy an iPhone? !!! Is it really impossible to create the simplest bootloader-manager as part of the package itself? The authors had enough skill to create an airplane. Set the price too. But making life for a virpil is a little easier - no)))

 

P/S/ Many companies write their own utilities and it is very convenient to use them. I don't like Apple!)

Edited by Candid
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@Candid Watching real Saab 340 flights i found out correct CTOT usage. Check provided tables to determine required torque for takeoff , you can find that in charts pdf in manuals folder. Let`s say charts gave you 100(And it is normal to get T.O. torque as high as 108 according to charts). Dial that in in CTOT but do not arm it, from what i gathered watching real flights they do that on takeoff run. When lined up advance throttles so that your torque gets close to what is dialed in CTOT- if you needed 100 advance to about 95 and then you arm CTOT so it keeps torque about 100 during T.O and initial climb. Once at acceleration altitude you dial CTOT down to 85-95(usually at 1000ft), again depending on climb charts(or for sim purposes you can do 85 always no big deal i do it that way) and disarm it.  Now you can fine tune throttles for climb. Hope this helps you, enjoy this excellent aircraft.

Edited by Milan Bogicevic
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2 hours ago, Candid said:

Note, that there is still a long way to go to a practical ceiling. D

Practical ceiling is around 25000 but boy is that a slow climb after 12000ft. Someone note here in Australia Rex dont go above 18000. How high do you expect to go.

Edited by mjrhealth
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2 hours ago, Candid said:

Fig. 3 I moved the ore all the way forward and got an increase in thrust and vertical speed, which is more like the truth. BUT!!! Engine speed is out of range !! The instructions describe little about the principles of СTOT operation. And in the example it is generally recommended not to touch the thrust levers after takeoff. How can I fly with such parameters?

 

There is a place called youtube filled with videos of takeoffs and landings. You disable CTOT after you start climbing. There is no auto throttle once you take off, you are it.

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On YouTube, videos of the same virpils as me. What to study there? Everyone flies as he knows how and as it is more convenient for him. In fact of the matter. that there is no real documentation to do like in real life.

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