Throttle_prop pitch synchronisation

[John Fee]

After a lot of mostly self-induced hair pulling, I have managed to set up the Dreamwings Dash Q400 to use CH Eclipse yolk, Saitek rudder pedals, and GoFlight TQ6 throttle quadrant.

I assigned the yoke to FS; the rudder pedals and the GF inputs are managed by FSUIPC.

This version of the Q400 has a customised panel which includes a merge with vasFMC gauges. This may be the reason my settings seem so difficult to get right. The aircraft models the FADEC engine control system in the RW plane giving basically four power settings - idle, climb (2 speed settings here), and TOGA. There are thrust reversers which work on the throttles.

I have two problems:

When I used a simple CH Flightstick Pro along with keyboard commands, it was possible to use the keyboard pitch controls to control the taxi speed with the throttles set at idle. This is neatly modelled in this version of the Dreamwings Q400 and is what happens in the RW aircraft as far as I know. (It is one of the delights of the plane, along with the superb sounds). I cannot do this with the set up above. In fact it is almost impossible to taxi since the throttle goes from idle to max thrust in three steps in the style of an Airbus.

I also cannot get the throttles to synchronise on autopilot. They are fine on manual but on switching to AP there is a 9% difference in torque (left engine > right). The relevant FSUIPC.ini details are below.

PropPitch1=-16209,-9063,512,16039

PropPitch2=-16203,-9002,512,16023

Throttle1=-16209,-9063,512,16035

Throttle2=-16203,-9002,512,16027

The FSUIPC.ini file is a bit of a mess - the result I suppose of many attempts to get things exactly right. I do not know the structure of this file or I would try to tidy it up manually. I could delete it and start again but I've spent so many days and nights setting up five aircraft of various types that I want to avoid doing that if possible.

Thanks for any help.

John

[John Fee]

Overnight, after a good few attempts, including four separate 'sync positions' in the calibration, I now have the difference between power outputs in the two engines down to 2% on AP. This is acceptable and probably similar to RW.

I have also discovered that this Q400 (again as in RW) uses the power output to adjust prop pitch and therefore taxi speed. As long as the prop pitch is set to be 'working' and not feathering, the power levers do the rest.

John

[Pete Dowson]

The aircraft models the FADEC engine control system in the RW plane giving basically four power settings - idle, climb (2 speed settings here), and TOGA.

Really analogue axes are not terribly suited to that sort of control. But FSUIPC does attempt to allow such "gate" systems by allowing assignments to specific, fixed, controls on the right-hand side of the Axis assignments tab -- the ability to assign controls to different ranges within the axis movement. Is this what you used?

When I used a simple CH Flightstick Pro along with keyboard commands, it was possible to use the keyboard pitch controls to control the taxi speed with the throttles set at idle. This is neatly modelled in this version of the Dreamwings Q400 and is what happens in the RW aircraft as far as I know. (It is one of the delights of the plane, along with the superb sounds).

The prop pitch controls, you mean? (When I first read that I was thinking elevator, which is of course your prime aircraft pitch control! ;-) ).

I cannot do this with the set up above. In fact it is almost impossible to taxi since the throttle goes from idle to max thrust in three steps in the style of an Airbus.

But if you are not using the throttles to taxi, what is the problem using pitch as you stated? I've obviously missed something

I also cannot get the throttles to synchronise on autopilot. They are fine on manual but on switching to AP there is a 9% difference in torque (left engine > right).

Do you mean on auto-throttle? The A/P controls throttles as well? If there is no autothrottle then there should be no difference at all between the throttle with A/P on or off. If there is an auto-throttle then then your throttle setting shouldn't have anything to do with it, surely?

Throttle1=-16209,-9063,512,16035

Throttle2=-16203,-9002,512,16027

So you aren't using the axis region facilities to assign fixed controls for your 4 modes? Wouldn't that be more precise? Perhaps that's the problem?

The FSUIPC.ini file is a bit of a mess - the result I suppose of many attempts to get things exactly right. I do not know the structure of this file or I would try to tidy it up manually.

Which parts of the file are you unsure of. most of those parts which users are expected to want to mess with are explained in the Advanced Users guide, and I can explain other parts for you if you wish.

Regards

Pete

[John Fee]

I'm very grateful for your advice, Pete. Thanks a bunch.

The aircraft models the FADEC engine control system in the RW plane giving basically four power settings - idle, climb (2 speed settings here), and TOGA.

Really analogue axes are not terribly suited to that sort of control. But FSUIPC does attempt to allow such "gate" systems by allowing assignments to specific, fixed, controls on the right-hand side of the Axis assignments tab -- the ability to assign controls to different ranges within the axis movement. Is this what you used?

No, I've not tried that, and to be honest, I'm not sure I want to. At the moment I seem to have something near to what I had before with the Flightstick. For me, that is progress!

When I used a simple CH Flightstick Pro along with keyboard commands, it was possible to use the keyboard pitch controls to control the taxi speed with the throttles set at idle. This is neatly modelled in this version of the Dreamwings Q400 and is what happens in the RW aircraft as far as I know. (It is one of the delights of the plane, along with the superb sounds).

The prop pitch controls, you mean? (When I first read that I was thinking elevator, which is of course your prime aircraft pitch control! ;-) ).

Yes, prop pitch. But, in fact since my first post I have discovered that the .air file or the aircraft.cfg file does this by adjusting prop pitch via the power settings at taxi, providing the props are not set to feather.

I cannot do this with the set up above. In fact it is almost impossible to taxi since the throttle goes from idle to max thrust in three steps in the style of an Airbus.

But if you are not using the throttles to taxi, what is the problem using pitch as you stated? I've obviously missed something

See above.

I also cannot get the throttles to synchronise on autopilot. They are fine on manual but on switching to AP there is a 9% difference in torque (left engine > right).

Do you mean on auto-throttle? The A/P controls throttles as well? If there is no autothrottle then there should be no difference at all between the throttle with A/P on or off. If there is an auto-throttle then then your throttle setting shouldn't have anything to do with it, surely?

The version I have has an autothrottle but it works with the FADEC. For example if I set speed to 170 knots for climb and VS 1500 ft/min the power settings will adjust to 155 knots for that climb. In cruise and descent the A/THR works normally but it's not very responsive and can vary by 10 knots or more. The RW aircraft has no autothrottle but here it is a great help for descents and on approach.

Throttle1=-16209,-9063,512,16035

Throttle2=-16203,-9002,512,16027

So you aren't using the axis region facilities to assign fixed controls for your 4 modes? Wouldn't that be more precise? Perhaps that's the problem?

Maybe.

The FSUIPC.ini file is a bit of a mess - the result I suppose of many attempts to get things exactly right. I do not know the structure of this file or I would try to tidy it up manually.

Which parts of the file are you unsure of. most of those parts which users are expected to want to mess with are explained in the Advanced Users guide, and I can explain other parts for you if you wish.

I am attaching the FSUIPC.ini but really do not expect you to spend precious time on it. I have 'profiles' I think on Dreamwings Malev Q400; Dreamwings Fokker 50 (Flugfelag Island); Dash 7 (Milton Shupe); Project Airbus A320; and Cessna Skyhawk (this is probably incorrectly set). Of these I only have confidence that the Q400 and the Airbus are correctly set up. Apart from that, there seems a lack of order to say the least!

Regards

John

It's not possible to upload FSUIPC.ini as .txt or .doc ??

[Pete Dowson]

Yes, prop pitch. But, in fact since my first post I have discovered that the .air file or the aircraft.cfg file does this by adjusting prop pitch via the power settings at taxi, providing the props are not set to feather.

... I cannot do this with the set up above. In fact it is almost impossible to taxi since the throttle goes from idle to max thrust in three steps in the style of an Airbus.

So I don't understand. Is it simply that the real throttle axis is interfering with the values the Prop Pitch is setting via the AIR file "fiddle"? If so you need to have a bigger idle "dead zone" to make sure there's no input from the real throttle axes when taxiing. Neither FS nor FSUIPC actually transmit any controls or values to the Sim Engine when the readings from joysticks are stable. Any jitter will, however, send values and have the adverse effect you describe.

You can also alter the "Delta" value in the FSUIPC axis assignmwents tab. A bigger value will ignore bigger changes. But take care that doesn't stop you using it normally.

It's not possible to upload FSUIPC.ini as .txt or .doc ??

I thought it was, but usually it is easiest simply to cut the relevant parts of the file out and paste them into your message as text, enclosed using the "Code" option, so they don't make the message impossibly long but are enclosed in a scrollable and selectable frame.

Regards

Pete

[John Fee]

I increased the dead zone but not the 'Delta' value. This helped and I am now beginning to get the hang of flying this bird. The throttles are synch'd to produce torque (TRQ) values within approx 3% of each other - this varies depending on the power setting - 0% at TOGA, 1% at idle, 2% at taxi (first gate), 3-4% at climb thrusts and cruise settings. So far I have kept prop pitch at full fine for all this testing but I will experiment with this. On the use of 'Sync Pos' - should this be activated when all the calibrations settings are at the desired values? Or in pairs? For example, when setting the max values for the two throttles? Then the same for the min values etc?

The settings now are:

Throttle 1: -16035, -9586, 512, 15512

Throttle 2: -16203, -9542, 356, 16205

The larger dead zone has helped with the taxi but even so, the tiniest pressure on either throttle lever will increase TRQ from 13% (idle) to 23% (taxi) - this TRQ delivers taxi speeds of up to 40 knots :shock: That is really the nub of the problem. Also, the AIR file makes constant adjustments so that when the throttle reaches a new 'gate' the TRQ takes time to balance.

I did not use autothrottle for any of this testing. For approach and landing I have found that if the TRQ is set to 40% (this matches one of the power 'gates') then once the initial approach speed is reached, the use of flaps at the designated speeds will result in the correct approach speeds - more or less. In a sense if you let it, this plane will fly itself.

Which brings me on to trim. It is vital for anyone flying this plane (Dreamwings Q400 with vasFMC mods for Malév Hungarian available on AVSIM) to disconnect the AP by at least at 1000 ft or 4-5 nm before runway threshold. This will give vital extra seconds to trim the plane, essential for control with AP disconnected at minimums and for a smooth landing. In Cat II it is probably best to wait till DH before disconnecting AP and to trim at 150 feet - not ideal I know.

Pete, I am not sure what you mean about using the axis calibrations on the right side to help with allocating power zones. That part of the panel seems to do with setting buttons and switches to do certain things under pre-defined conditions. For example when a particular throttle setting is reached the landing gear will deploy. I cannot see how this section can be used to 'zone' power output via throttle axes. Have I missed something? Not again, surely!

Best regards

John

[Pete Dowson]

On the use of 'Sync Pos' - should this be activated when all the calibrations settings are at the desired values? Or in pairs? For example, when setting the max values for the two throttles? Then the same for the min values etc?

You need to calibrate every lever properly first, with special care with Engine 1 levers, because they won't change thereafter and are used as the "measure" for recording the equivalent positions on all the others. Naturally get them lined up for min. centre and max positions. The sync positions are only taking care of making them match correctly at the intermediate positions.

Don't go overboard with too many "sync" positions -- depending how bad the alignment is you shouldn't need many. FSUIPC will replace any too close though, using the latest.

The larger dead zone has helped with the taxi but even so, the tiniest pressure on either throttle lever will increase TRQ from 13% (idle) to 23% (taxi)

Sounds like there's no real dead zone then. You could make a dead zone span half of the movement available if you wanted to. I'm sure you should be capable of making it enough so that a slight movement will be ignored -- providing you leave it in its parked position of course.

With these settings:

Throttle 1: -16035, -9586, 512, 15512

Throttle 2: -16203, -9542, 356, 16205

where are you "parking" the throttles whilst taxiing? In the centre idle position? If so there should surely be enough movement available with that 10,000 odd space. You certainly don't seem to have any noticeable "dead zone" at either minimum or maximum positions -- 16383 is the very limit of possibility.

I am not sure what you mean about using the axis calibrations on the right side to help with allocating power zones. That part of the panel seems to do with setting buttons and switches to do certain things under pre-defined conditions. For example when a particular throttle setting is reached the landing gear will deploy. I cannot see how this section can be used to 'zone' power output via throttle axes. Have I missed something?

No, you describe it exactly. If you have predefined throttle settings, values to be sent to establish different thrust modes, as in an Airbus, then that is precisely "doing certain things under pre-defined conditions". For 4 different throttle modes you'd delineate 4 regions on the throttle and in each one assign the AXIS_THROTTLE_SET control with the one, single, fixed throttle value which will give you that setting in the aircraft's engine control system.

I think some Airbus implementations actually use fixed controls or keypresses to select throttle modes, in which case those controls or keypresses would be sent instead, but it sounds like your aircraft needs the actual throttle values but interprets ranges rather than specific values. So why not send the correct specific values in the first place?

Regard

Pete

[John Fee]

You need to calibrate every lever properly first, with special care with Engine 1 levers, because they won't change thereafter and are used as the "measure" for recording the equivalent positions on all the others. Naturally get them lined up for min. centre and max positions. The sync positions are only taking care of making them match correctly at the intermediate positions. Don't go overboard with too many "sync" positions -- depending how bad the alignment is you shouldn't need many. FSUIPC will replace any too close though, using the latest.

Okay, but I will leave this adjustment till last.

Sounds like there's no real dead zone then. You could make a dead zone span half of the movement available if you wanted to. I'm sure you should be capable of making it enough so that a slight movement will be ignored -- providing you leave it in its parked position of course.

With these settings:

Throttle 1: -16035, -9586, 512, 15512

Throttle 2: -16203, -9542, 356, 16205

where are you "parking" the throttles whilst taxiing? In the centre idle position? If so there should surely be enough movement available with that 10,000 odd space. You certainly don't seem to have any noticeable "dead zone" at either minimum or maximum positions -- 16383 is the very limit of possibility.

You misunderstand this bit. There is a 'dead' zone. The throttle lever moves maybe 2 cm between the lever positions which give a TRQ of 13% and 23% . The problem is that the TRQ suddenly jumps from 13% to 23% once I hit the next 'active' part of the travel. In this way, although there is a 2cm dead zone, at the upper end of the zone there is only millimetres between TRQ 13 and TRQ 23. There is nothing in between these values. I suppose the throttle control values reach a 'gate' which triggers this jump. Is there any way to produce an intermediate value between 13 and 23 for TRQ? Or is that built into the .air file? Or the aircraft.cfg file?

I think some Airbus implementations actually use fixed controls or keypresses to select throttle modes, in which case those controls or keypresses would be sent instead, but it sounds like your aircraft needs the actual throttle values but interprets ranges rather than specific values. So why not send the correct specific values in the first place?

Do you mean I should use the right hand side of the panel to send the correct ranges in the first place? If so, how can I do this without using buttons or switches? These seem to be the only controls available on the right side.

The Dreamwings Dash 8 Q400 engine controls seem to be set up exactly like an Airbus.

Thanks again for your patience with this.

Rgrds

John

[Pete Dowson]

You misunderstand this bit. There is a 'dead' zone. The throttle lever moves maybe 2 cm between the lever positions which give a TRQ of 13% and 23%

With 2cm of travel surely a little "nudge" as you call it shouldn't change things. you should have the lever in the middle of the 2 cm really. And in any case a "dead zone" is one which sends nothing at all to the sim, it is an area calibrated with no changes whatsoever. i.e "dead".

The problem is that the TRQ jumps from 13% to 23% once I hit the next 'active' part of the travel. There is nothing in between these values. I suppose the throttle control values reach a 'gate' which triggers this jump. Is there any way to produce an intermediate value between 13 and 23 for TRQ? Or is that built into the .air file? Or the aircraft.cfg file?

No, of course not. The throttle values are changing continuously between them, it isn't anything on the input side which is interpreting the values as 13 and 23%. That's something in your specific aircraft model.

The whole problem would be easy peasy to solve using zones on the right-hand side of the axis assignments, one well-defined zone to set each individual value which the AIR file needs to set its thrust. You could have a nice little dead zone between each 'gate' that way.

Do you mean I should use the right hand side of the panel to send the correct ranges in the first place? If so, how can I do this without using buttons or switches? These seem to be the only controls available on the right side.

Yes, "controls". But there are only "controls" available on the left hand side too! AXIS "controls" are "controls"! You can assign to ANY controls on the right -- AXIS ones, same as on the left, as well as other controls, not available on the left. Why not just look, use the drop down, and see? I think you misunderstand what "controls" means -- it includes all your axis controls as well as those usually assigned to buttons and keypresses! Plus all those added by FSUIPC for doing all sorts of fancy things. Hundreds of them!

You need to specify a parameter with the AXIS controls, which will be forwarded to the Sim unmolested. Don't calibrate, no need for that then. You just program your 4 zones for the 4 throttle "gates" and assign the axis control with a fixed parameter which makes the air file set that gate. I have no idea what the parameter should be -- you could find out by determining the centre of the range of "OUT" values at present which engage that gate setting.

You can use "Axis throttleN set" (N = 1 to 4 for 4 engines), which has a range of -16383 to +16383, or "ThrottleN Set", which has a range of 0 to 16383 (the negative values are for reverse thrust).

BTW With all this trouble I would expect 99% of the purchasers of this aircraft to have immense difficulty. Are you the only one using it? If not, have you had a look to see if there's a Forum somewhere where users are solving things?

Regards

Pete

[John Fee]

With 2cm of travel surely a little "nudge" as you call it shouldn't change things. you should have the lever in the middle of the 2 cm really. And in any case a "dead zone" is one which sends nothing at all to the sim, it is an area calibrated with no changes whatsoever. i.e "dead".

No because when the upper limit of the 'dead' zone is reached another nudge takes TRQ from 13 to 23. Clearly this is built into the .air file but I hoped that FSUIPC might allow me to change this.

The whole problem would be easy peasy to solve using zones on the right-hand side of the axis assignments, one well-defined zone to set each individual value which the AIR file needs to set its thrust. You could have a nice little dead zone between each 'gate' that way.

You need to specify a parameter with the AXIS controls, which will be forwarded to the Sim unmolested. Don't calibrate, no need for that then. You just program your 4 zones for the 4 throttle "gates" and assign the axis control with a fixed parameter which makes the air file set that gate. I have no idea what the parameter should be -- you could find out by determining the centre of the range of "OUT" values at present which engage that gate setting.

You can use "Axis throttleN set" (N = 1 to 4 for 4 engines), which has a range of -16383 to +16383, or "ThrottleN Set", which has a range of 0 to 16383 (the negative values are for reverse thrust).

Easy peasy for me it weren't! :wink: Try as I might I could not get consistent results with this. The main problem was synchronising the two throttles for several 'active' and 'dead' zones for left and right engines.

BTW With all this trouble I would expect 99% of the purchasers of this aircraft to have immense difficulty. Are you the only one using it? If not, have you had a look to see if there's a Forum somewhere where users are solving things?

This was a freeware plane so no purchasers! I am certainly not the only one using it - there is quite a little gang of us! But I may well be the only one using it with the GoFlight throttle quadrant. The throttles I suspect were designed to be used with keyboard controls. Either that or a joystick wheel controlling two engines. Both those worked well for me. The problem has been the throttle quadrant.

I will fiddle on with this and if I find settings which are consistent and produce the desired results I'll maybe post again.

Thanks for your help, Pete.

Regards

John

[Pete Dowson]

No because when the upper limit of the 'dead' zone is reached another nudge takes TRQ from 13 to 23.

But surely you park it in the centre of the calibrated zone for 13. Why are you nudging it into different zones? surely you only want to do that when you actually want to select different zones! If the lever wouldn't move into those zones it would be pretty useless to you, after all!

In other words, you can't expect to have a moveable lever programmed to select something for you and then not have it do so when you move it. After all, that is what it is for.

If you want to be able to waggle it about as you please with no effect whatsoever you need a little plug-in to disconnect the throttle input for you until you press a button to reenable them. That's easy enough to do in Lua. It would be started by a button press, loop setting the throttle inhibit flags in offset 310A every few seconds until you pressed another button, then clear those inhibits.

Clearly this is built into the .air file but I hoped that FSUIPC might allow me to change this.

Change it to do what, exactly? Operate like a normal aircraft? Sorry, maybe I'm missing your point entirely, in which case I apologise.

The main problem was synchronising the two throttles for several 'active' and 'dead' zones for left and right engines.

You simply set the zone entries and exits, one at a time, with the levers lined up as you do so. Use a straight edge or clip them together.

Regards

Pete

[John Fee]

But surely you park it in the centre of the calibrated zone for 13. Why are you nudging it into different zones? surely you only want to do that when you actually want to select different zones! If the lever wouldn't move into those zones it would be pretty useless to you, after all!

I'm nudging it because I want a torque of 16-18. At 13 the engines are at idle. At 23 we are doing 50 knots. I don't taxi at 50 knots. I am tweaking the aircraft.cfg file in order to try to control this runaway tendency. I cannot do it with FSUIPC.

The good news is that I now have working profiles for twin jets and single engined pistons. I am close to getting something acceptable for the Dreamwings Dash 8. This has been a very difficult aircraft to set up with the GoFlight TQ6 throttle quadrant. The reason is that torque is programmed to increase in a step-wise and not a linear fashion. Oddly, these step-wise increments (or should I say decrements) do not occur as power is reduced. To reduce torque for descent, the levers must be brought back to idle and then advanced to the lower setting (e.g. to reduce from TRQ 65% to TRQ 35%). This behaviour seems to be programmed into the .air file and I have not been able to modify it using FSUIPC. The same thing happens when using keyboard controls.

John

[Pete Dowson]

I'm nudging it because I want a torque of 16-18. At 13 the engines are at idle.

I thought you said you controlled taxi speed with prop pitch, or not throttle. Why aren't you not simply putting the throttle lever into the correct zone and leaving it there?.

Sorry, this thread is ultra confusing. I really think you need to sort out what the aircraft designer intended with him or her.

The good news is that I now have working profiles for twin jets and single engined pistons. I am close to getting something acceptable for the Dreamwings Dash 8. This has been a very difficult aircraft to set up with the GoFlight TQ6 throttle quadrant.

But the levers on the TQ6 are no different to any levers at all on any similar device. They are simply analogue inputs.

The reason is that torque is programmed to increase in a step-wise and not a linear fashion.

Which is why I have been continually suggesting the use of the FSUIPC facilities to set discrete zones with fixed separate resulting control values going to the sim.

This behaviour seems to be programmed into the .air file and I have not been able to modify it using FSUIPC.

FSUIPC is not an AIR file editor, that is why. However, it does have facilities you either do not want to use or do not understand. I cannot really help further, I have tried my best.

The same thing happens when using keyboard controls.

Yet keyboard control is comparatively discrete, not continuous. Are you sure the aircraft designer has just made an impossible design after all?

Regards

Pete

[John Fee]

Many thanks. You have indeed tried your best. It is quite possible that the designer has made an impossible design.

Regards

John