Trouble with Throttles and FSUIPC

[XOrionFE]

I am trying to calibrate my two throttles in FSUIPC 4.3 for FSX (Learjet) and cannot get them to work correctly. The pots are reversed from each other in my setup. Thottle 1 when pushed full forward gives a negative value and when pulled back reads a positive. Thottle 2 is opposite. It reads positive when pushed forward and negative going back (like you would expect). Even when I check REV box on Throttle 1 and then reset and set it still reads from positive to negative values as I push forward. This makes it damn near impossible to correctly set the values for Reverse, Idle, and Max as they want to be in ascending order. If and when I get that squared away, when pulled all the way back they activate Reverse Thrust which I do not want them to do. I cannot get rid of the reverse portion in FSUIPC. I know this has to do something with Reverse thrust settings in the .air file but I dont have a clue how to edit or if one even should. I want to have the levers go back to idle detent and be at idle but then when I go past Idle detent and back to full minimum throw I dont want reversers I just want nothing or Throttle Cut. I realize I may have to put a switch back there for throttle cuttoff but it appears you can do this within FSUIPC somehow also.
I have seperate reverse thrust levers that will activate microswitches for Reverse Thrust.

Long winded I know....

Can anyone offer some tips?

Thank you

Scott

[Kennair]

Hi Scott,

Why don't you just assign your throttles in FS itself and not use FSUIPC. I know Pete has suggested this on many occasions in response to problems. Basically if you only want plain operating axis, just let FS handle them. And of course FS doesn't employ reverse thrust for their axis.

As for setting the values, I also have particular axis that work in reverse, however it's no problem, you just set whatever is the minimum value (i.e. -64385 for example) in the left box and the upper +ve value in the right box. It shouldn't matter whether you are pushing forward or pulling back to achieve this, FSUIPC just needs to know the range of vaules. You check the REV then to correct for your required movement. As for the reversing range problem, I would have thought that setting the two so-called reverse settings to equal the lower limit would negate the Reversing function by I could be wrong. My throttles are setup for reversing as I have a mechanical reversing gate to achieve this.

I hope I've understood your problem and answered correctly?

Ken.

[Michael Carter]

I did what Ken suggests. FSUIPC would not calibrate my throttles correctly. No matter how much I worked with it, the axis were reversed, not enough throw on the throttle lever, or zero power & full power were the only settings.

I gave up and let FS handle the throttles. Not one problem since.

FSUIPC does everything great except throttles for some reason.

[Peter Dowson]

I did what Ken suggests. FSUIPC would not calibrate my throttles correctly. No matter how much I worked with it, the axis were reversed, not enough throw on the throttle lever, or zero power & full power were the only settings.

I gave up and let FS handle the throttles. Not one problem since.

FSUIPC does everything great except throttles for some reason.

Odd that no one ever comes to my Support Forum and says these things? FSUIPC has always been excellent with throttles (that was one of the first things supported so that reversers could be added). And there's no way any problems are going to be resolved if folks don't come and ask, but just stop using it instead! How does that help anyone?

Reversal is simply a checkbox. Both FS and FSUIPC have reversal capabilities. Double reversal isn't good.

FSUIPC, like FS itself, treats all axes alike, or at least in two groups -- those which natural centres like aileron, elevator, rudder, and those with no centres or off-centred centres, like brakes, throttles, prop pitch, mixture, spoiler and flaps. If you have problems with throttle calibration you must for sure have problems with all the others, as there's no essential differences.

The Saitek throttle quadrants have an installation error which causes the left-most two levers to be recognised only as digital (on or off) controls, like a game pad, to any program not using DirectInput (like FSUIPC3. FSUIPC4 uses DirectInput for axes, but not FSUIPC3). The fix is a registry edit it seems -- I don't know wehy Saitek don't fix their installer. Maybe other devices also have similar problems. I think some of these companies don't test their installations fully.

Pete

[Jackpilot]

I built my TQ with pots and calibration of the whole thing with FSUIPC was no prob. Especially the use of a pot for the flap (and speedbrake) lever allows simple construction and precise detents positionning.
Had some difficulties though to synchronize the two power levers...which is a pain during low power manual approaches.
Jack

[Peter Dowson]

Had some difficulties though to synchronize the two power levers...which is a pain during low power manual approaches.

Two hints there.

First, never use a "slope" on throttles, unless you have to because the pot inside the device is logarithmic instead of linear (most unlikely). Just be sure the slope option is set to its default of 0 (straight lines).

Second, assuming your two (or more) levers are truly identical, then you can calibrate one well, the others roughly, then simply go into the FSUIPC INI file and copy the set of good numbers over the rough ones for the other levers. That way you are sure to get the same numbers on each.

If the pots in the device(s) aren't truly identical, or there's more capacitance or inductance or whatever in one wire than the other, then the inputs from them might still not quite match. You need to watch the N1% or RPM, not the lever positions. Some discrepancy in the positions of throttles is quite realistic, though -- as you can see from cockpit videos. The throttles are rarely exactly in line for exactly the same thrust. (The Airbus is of course different in this respect as their "thrusters" are more like mode selectors).

I still believe the numerical method of calibrating used in FSUIPC is capable of far more precision than those methods which simply relay on watching blobs move about.

Regards

Pete

[ian@737ng.co.uk]

hi guys....
i have to agree with both peter and Jackpilot. all my axes are calibrated using FSUIPC and work a charm.
however going back to the original question, maybe a dumb suggestion, but if all else fails, swap the 0v and 5v leads on the offending pot. that'll fix it.
have a great evening chaps.....
regards ... ian

[XOrionFE]

Two hints there.

First, never use a "slope" on throttles, unless you have to because the pot inside the device is logarithmic instead of linear (most unlikely). Just be sure the slope option is set to its default of 0 (straight lines).

Second, assuming your two (or more) levers are truly identical, then you can calibrate one well, the others roughly, then simply go into the FSUIPC INI file and copy the set of good numbers over the rough ones for the other levers. That way you are sure to get the same numbers on each.

If the pots in the device(s) aren't truly identical, or there's more capacitance or inductance or whatever in one wire than the other, then the inputs from them might still not quite match. You need to watch the N1% or RPM, not the lever positions. Some discrepancy in the positions of throttles is quite realistic, though -- as you can see from cockpit videos. The throttles are rarely exactly in line for exactly the same thrust. (The Airbus is of course different in this respect as their "thrusters" are more like mode selectors).

I still believe the numerical method of calibrating used in FSUIPC is capable of far more precision than those methods which simply relay on watching blobs move about.

Regards

Pete

Ok,

First off Pete, I went to your forum late last night at about Midnight and found I had forgotten what username I had put there and was tired so just ended up posting my question here but I will make an effort tonight to try again and then get on your forum.

I have an actual set of Learjet Throttles and am using gearing and 100K Ohm Linear Taper pots from Radio Shack. They are facing each other so one is the reverse of the other (although I never though of changing the wiring to create my own reverse).

I do not have them configured at all in FSX but only in FSUIPC. I tried the REV checkbox a multitude of times. I still dont understand why the REV checkbox has no effect on the values being Negative at Full throttle versus Positive at Low Throttle and the applet doesnt seem to allow you to set Reverse, Idle, and Max in that order? I must be doing something wrong. I read your manual and played with it for over two hours last night until I finally gave up and went to bed. I also still dont understand how I can make it so there is no reverse thrust zone. I have an Idle detent and anything behind that needs to be throttle cutoff not reverse thrust.

So I have two problems. One, how to make values be read negative at low throttle and postive at max when the REV checkbox doesnt seem to have an effect on this, and two, how to I get rid of Reverse thrust (my reversers are different set of switches).

If there isnt an answer in FSUIPC then I can see where just setting in FSX makes more sense.

Any help is appreciated Pete. BTW - I do have spoilers and flaps and those I have working perfectly within fsuipc and all zones and detents work great. It is the throttles that are killing me.

Scott

[Jackpilot]

I may be wrong but as far as I remember the figures always go from minus something to plus something, negative values have nothing to do with reverse.
Maybe one of your pots has to be wired opposite of what it is and both will work the same way.
Then you can calibrate from idle to max power and wire your reverse switches to command F2 with a repeat.
Cheers
Jack

[Peter Dowson]

I do not have them configured at all in FSX but only in FSUIPC. I tried the REV checkbox a multitude of times. I still dont understand why the REV checkbox has no effect on the values being Negative at Full throttle versus Positive at Low Throttle and the applet doesnt seem to allow you to set Reverse, Idle, and Max in that order?

The calibration is prohibited from having those out of order. The "minimum" or "max reverse" setting must be lower (or more negative if it goes negative -- not all axes do) than either of the centre or "idle" zone settings which must in turn be lower than the max (max thrust) setting.

That is the only imposition. It will not allow you to violate that rule (if it did it would really mess up the interpolation computations like crazy!).

So, if you somehow got a negative value in the max position, or a big positive value in the rev thrust or minimum position, you have to correct those first.

That is all. there are NO OTHER RULES there, only the imposition of order, low on left to high on right. The middle two have to be between the other two but themselves may be in either order. they just define the idle zone -- and it must be a zone, not just a "point". (There's really no such thing as a single selectable point on an analogue axis, even with detentes).

If your levers are acting in reverse, then you should select the REV option BEFORE doing the calibration. Otherwise the interpolations will be wrong. Reversing after calibrating is not good unless the axis is truly symmetrical, like aileron, elevator and rudder. Obviously for symmetrical axes the reversal is simple. For centres which are not truly central it gets the ranges into a real mess. So calibrate AFTER getting the direction correct.


I must be doing something wrong. I read your manual and played with it for over two hours last night until I finally gave up and went to bed.

I just can't imagine how it can take more than a couple of minutes at most. It is so stark-ravingly simple! What you see is exactly what you get. There's nothing hidden, nothing clever. It's just saying "my axis runs from here, which is where I want reverse, to here which is where I want idle to start, to here, which is the end of the idle zone, to here, where I want max thrust. That's it. Dead simple, nothing hidden, no magic.

I always advise making the two extremes a little away from your real extreme values, so you can be sure of always reaching them even with expected variations in the pot readings -- and you do get those. They vary with humidity, temperature, dirt, and so on.

The documentation only says the same. But mostly it is entirely intuitive and 99% of users find it so. I don't understand why some don't -- must be some sort of number blindness. Some folks are more graphically minded instead I assume. I prefer numerical precision.


I also still dont understand how I can make it so there is no reverse thrust zone. I have an Idle detent and anything behind that needs to be throttle cutoff not reverse thrust.

Well, the whole system is really designed to provide a nice reverse thrust capability, that's why it was done, but you should be able to achieve that by making the one of the two centre/idle values as close as possible to the minimum value. Ideally the minimum value should be below the lowest negative number you can achieve, but of course you can't set that with the axis as it won't get there. You might be able to improve it by editing the numbers in the INI file afterwards. But you have to make the whole area, from just above your idle detente (to allow for variation as i said) to as close as you can get to the minimum, all part of the idle zone -- i.e. the two centre values.

That's all. It's much easier to do than describe.


If there isnt an answer in FSUIPC then I can see where just setting in FSX makes more sense.

Well, in the 10+ years FSUIPC has featured this facility I've only had about three requests asking how to remove the reverse zone, and my answer above has worked for those users. If there were a general clamour for it I would have added another set of 4 throttles with no reverse zone, or simply put such an option on that page, but it didn't seem to be needed and so would just make things more complex than necessary.

But please yourself. Use FS assignments if you really find this so so difficult. I just don't understand why. :-(

Pete

[Michael Carter]

I am using five identical professional grade 100mm Panasonic linear slide pots for all axis.

The flaps and speedbrake are working fine. I've never had trouble with either of those two axis.

The three throttle pots refuse to cooperate with FSUIPC. During some programming attempts the throttle pots aren't even recognized as being hooked up. FS and the input card sees them just fine.

Other attempts have had one, two, and sometimes all three being recognized, but still unable to calibrate correctly one or more throttles. I've been using the program long enough to know how to calibrate an axis, including how to avoid a reverse thrust setting at the idle stops.

I've also tried copying one good throttle configuration from the .ini file to the other two throttles with no better luck than trying to perform a manual calibration through the GUI.

[XOrionFE]

The calibration is prohibited from having those out of order. The "minimum" or "max reverse" setting must be lower (or more negative if it goes negative -- not all axes do) than either of the centre or "idle" zone settings which must in turn be lower than the max (max thrust) setting.

That is the only imposition. It will not allow you to violate that rule (if it did it would really mess up the interpolation computations like crazy!).

So, if you somehow got a negative value in the max position, or a big positive value in the rev thrust or minimum position, you have to correct those first.

That is all. there are NO OTHER RULES there, only the imposition of order, low on left to high on right. The middle two have to be between the other two but themselves may be in either order. they just define the idle zone -- and it must be a zone, not just a "point". (There's really no such thing as a single selectable point on an analogue axis, even with detentes).

If your levers are acting in reverse, then you should select the REV option BEFORE doing the calibration. Otherwise the interpolations will be wrong. Reversing after calibrating is not good unless the axis is truly symmetrical, like aileron, elevator and rudder. Obviously for symmetrical axes the reversal is simple. For centres which are not truly central it gets the ranges into a real mess. So calibrate AFTER getting the direction correct.



I just can't imagine how it can take more than a couple of minutes at most. It is so stark-ravingly simple! What you see is exactly what you get. There's nothing hidden, nothing clever. It's just saying "my axis runs from here, which is where I want reverse, to here which is where I want idle to start, to here, which is the end of the idle zone, to here, where I want max thrust. That's it. Dead simple, nothing hidden, no magic.

I always advise making the two extremes a little away from your real extreme values, so you can be sure of always reaching them even with expected variations in the pot readings -- and you do get those. They vary with humidity, temperature, dirt, and so on.

The documentation only says the same. But mostly it is entirely intuitive and 99% of users find it so. I don't understand why some don't -- must be some sort of number blindness. Some folks are more graphically minded instead I assume. I prefer numerical precision.



Well, the whole system is really designed to provide a nice reverse thrust capability, that's why it was done, but you should be able to achieve that by making the one of the two centre/idle values as close as possible to the minimum value. Ideally the minimum value should be below the lowest negative number you can achieve, but of course you can't set that with the axis as it won't get there. You might be able to improve it by editing the numbers in the INI file afterwards. But you have to make the whole area, from just above your idle detente (to allow for variation as i said) to as close as you can get to the minimum, all part of the idle zone -- i.e. the two centre values.

That's all. It's much easier to do than describe.



Well, in the 10+ years FSUIPC has featured this facility I've only had about three requests asking how to remove the reverse zone, and my answer above has worked for those users. If there were a general clamour for it I would have added another set of 4 throttles with no reverse zone, or simply put such an option on that page, but it didn't seem to be needed and so would just make things more complex than necessary.

But please yourself. Use FS assignments if you really find this so so difficult. I just don't understand why. :-(

Pete


It may be nothing wrong with your program and I am pretty certain I understand how it is SUPPOSED to work. Bottom line is that on one of my throttles the values go from being positive at low throttle position to Negative at high. And because the REV checkbox has NO effect on this (yes I set it before calibrating) I am unable to set it properly (Rev, Idle, Max) because as you said the program is designed to have values go from negative to positive (which makes sense). What you are saying about right now about getting rid of the reverse thrust zone now makes sense to me (if it was stated that way in your docs it would be helpful probably for others that want to do this in the future).

I am going to go mess with the wires and if I can get the values to work in the right direction I should be able to do what you said and remove the reverse.

[Tomlin]

Scott-

Hang in there. For some reason things dont always work the way that we assume that they will and when that happens, we sometimes get stuck in a rut expecting one result and getting another, and of course frustration insues and we make no progress. Keep your chin up- what you need to do is very possible using FSUIPC but maybe step back and take a break for a while and give it another try later. I have had this happen on numerous issues before, and a break is almost always a good temp solution.

[XOrionFE]

Thanks Eric,

I just figured out part of the issue and that is that by reversing the wiring on the pot I took care of my problem with low being positive and high being negative. So it is not FSUIPC but I got fixated on that damned REV checkbox and kept thinking it should be managing the direction of the values. The reality is that only the wiring could do that. (Pete - I am going to read your doc again but perhaps putting something in there that says if your values are not going from negative to positive you have to reverse your wires...etc).

Anyway, it is working now. I am still fighting a little with getting rid of the reverse thrust zone but not because FSUIPC but because my pot values fluctuate and so sometimes it is working and sometimes not. I did try editing the .ini file but it didnt seem to stick or work as I still get the reverse now and then. This is a cool feature (reverse thrust zone) for throttles without reverse thrust levers but of course that is not the case with the learjet.

Now I just need to get it to be consistant (maybe better pots...) and I will also have to put some switches on the back side that can be activated by pulling the levers all the way back to stops and thus make them activate the cutoffs.

Thank you for your help Pete. Remember, you wrote the program so of course it is simple in your mind. For the rest of us we may not always see the obvious. And by the way, I am a numerical thinker also.....

Scott

[XOrionFE]

Thank you Jack and Ian for helping by pointing out the wiring of the pots. That did it.

[Peter Dowson]

Pete - I am going to read your doc again but perhaps putting something in there that says if your values are not going from negative to positive you have to reverse your wires...etc).

That really should be completely unnecessary. I cannot imagine what you were doing, but all the REV button does is active a little line in the code which inverts the input it is receiving BEFORE passing it on for calibration. In other words it simply does "N = -N". That should be enough. It works here, as it always has worked. It is effectively the same as the Reverse facility in FS itself. It isn't complicated, it is simply that.

You should NEVER have to reverse the input, and I really cannot advise that in the documentation. You forget that 99.99% of FSUIPC users use ready-made joysticks and throttles, not home made gear.


my pot values fluctuate and so sometimes it is working and sometimes not.The more the values vary the greater the dead zones need to be on the calibration. It is a shame. You start losing too much movement.


I did try editing the .ini file but it didnt seem to stick

INI values remain in use and unchanged unless you go into the calibration tabs and change them. They are only ever written there or by your own editing.


This is a cool feature (reverse thrust zone) for throttles without reverse thrust levers but of course that is not the case with the learjet.

The usual way to deal with this is surely to have the thruster and reverser pots in series. Then the thruster pot gets part of the range, and you calibrate it with idle zone and max thrust zones, and calibrate the reverser part (in the same FSUIPC section) with the reverser lever.


Now I just need to get it to be consistant (maybe better pots...) and I will also have to put some switches on the back side that can be activated by pulling the levers all the way back to stops and thus make them activate the cutoffs.

Cutoffs are operated by the thrust levers on a Learjet, not separate levers? Does that work the other way too (to start)? Sounds a bit dodgy.

Regards

Pete

[XOrionFE]

That really should be completely unnecessary. I cannot imagine what you were doing, but all the REV button does is active a little line in the code which inverts the input it is receiving BEFORE passing it on for calibration. In other words it simply does "N = -N". That should be enough. It works here, as it always has worked. It is effectively the same as the Reverse facility in FS itself. It isn't complicated, it is simply that.

You should NEVER have to reverse the input, and I really cannot advise that in the documentation. You forget that 99.99% of FSUIPC users use ready-made joysticks and throttles, not home made gear.

The more the values vary the greater the dead zones need to be on the calibration. It is a shame. You start losing too much m


INI values remain in use and unchanged unless you go into the calibration tabs and change them. They are only ever written there or by your own editing.



The usual way to deal with this is surely to have the thruster and reverser pots in series. Then the thruster pot gets part of the range, and you calibrate it with idle zone and max thrust zones, and calibrate the reverser part (in the same FSUIPC section) with the reverser lever.



Cutoffs are operated by the thrust levers on a Learjet, not separate levers? Does that work the other way too (to start)? Sounds a bit dodgy.

Regards

Pete

Not sure about 99% of users but in my case the rev didnt do the job but changing the wiring did.

As for cutoffs, on the learjet the thrust levers do handle the cutoff. Cutoff is achieved by overcoming the Idle dentent and pulling th ethrottles all the way back to the stops. So right now I set the bottom most Travel point of the levers in Reverse Zone. Then I set the Low end of Idle to the same value and the high end of Idle to just forward of the Idle detent/stop. I shut down FSX and went into the .ini file and edited the second value on each line (Idle Min) to be about 100 more negative then the Reverse Value (I am assuming the values are Reverse, Idle Min, Idle Max, Max. Does this sound like what you were intending?
As for cutoff then, not sure how I could setup other than using a switch that would get engaged by pulling the handles all the way back then mapping the switch to the cutoff command with my encoder.
I did see that you can map a key to a zone in the axis assignment tab. havent tried that though yet. Might that work for this if I set the bottom range (Reverse to Idle Low for instance) to assign Throttle Cutoff command?

Thanks Pete

[Peter Dowson]

Not sure about 99% of users but in my case the rev didnt do the job but changing the wiring did.

Yes, but it isn't logical ("it does not compute") because the REV button simply changes the sign. It can't fail to reverse the direction, so it is very very puzzling. As I cannot see your PC and you using it from here I don't know what exactly you are doing to get this to happen. Shame. Maybe if i saw what you were doing it would be immediately obvious.


As for cutoffs, on the learjet the thrust levers do handle the cutoff. Cutoff is achieved by overcoming the Idle dentent and pulling th ethrottles all the way back to the stops.Yes, you said that already. What I asked was does it do the reverse, i.e. automatically enable the fuel when you push the levers off the stops? As I said, it seems a bit dodgy to me if it does.


right now I set the bottom most Travel point of the levers in Reverse Zone. Then I set the Low end of Idle to the same value and the high end of Idle to just forward of the Idle detent/stop.Sounds good.


I shut down FSX and went into the .ini file and edited the second value on each line (Idle Min) to be about 100 more negative then the Reverse ValueInteresting. I'd have to look at the code to see what that might actually do. Does it work?


(I am assuming the values are Reverse, Idle Min, Idle Max, Max. Does this sound like what you were intending?Not really. I think it should work if the values are the same. That's what most folks do. I'd need to work through the code to check exactly.


As for cutoff then, not sure how I could setup other than using a switch that would get engaged by pulling the handles all the way back then mapping the switch to the cutoff command with my encoder.Well a button or microswitch would work. Not sure why you'd need any encoder. Can't you feed buttons/switches through your controller board as joystick button presses? Then simply program it in FSUIPC or FS.


I did see that you can map a key to a zone in the axis assignment tab. havent tried that though yet. Might that work for this if I set the bottom range (Reverse to Idle Low for instance) to assign Throttle Cutoff command?Yes, you can do that. However you've got no range from reverse to idle low and if you had any it would activate reverse because of the axis arrangement, notwithstanding any control assignments on the right-hand side.

BTW FS doesn't sport a control known as "throttle cut-off". You have to use Mixture Lean.

Regards

Pete

[XOrionFE]

Yes, but it isn't logical ("it does not compute") because the REV button simply changes the sign. It can't fail to reverse the direction, so it is very very puzzling. As I cannot see your PC and you using it from here I don't know what exactly you are doing to get this to happen. Shame. Maybe if i saw what you were doing it would be immediately obvious.

Yes, you said that already. What I asked was does it do the reverse, i.e. automatically enable the fuel when you push the levers off the stops? As I said, it seems a bit dodgy to me if it does.

Not sure but I will check. I am still trying to learn how they really are supposed to work. Your assumption is probably correct. I will check with Mr. Learjet...Eric Tomlin
Sounds good.

Interesting. I'd have to look at the code to see what that might actually do. Does it work?

Didnt seem to matter. The best result I got was just having the Reverse and low Idle values be the same like you said setting them through the interface. I know that if I changed the value in the .ini and then went back to the interface, it was not reflected in the interface.
Not really. I think it should work if the values are the same. That's what most folks do. I'd need to work through the code to check exactly.

Yes, that is what I did and where I left it for now.
Well a button or microswitch would work. Not sure why you'd need any encoder. Can't you feed buttons/switches through your controller board as joystick button presses? Then simply program it in FSUIPC or FS.

Yes, that is what I meant. I will feed it through my Hagestrom controller board.
Yes, you can do that. However you've got no range from reverse to idle low and if you had any it would activate reverse because of the axis arrangement, notwithstanding any control assignments on the right-hand side.

oops, yes you are righht and I didnt think of that. I will just use microswitches.
BTW FS doesn't sport a control known as "throttle cut-off". You have to use Mixture Lean.

Didnt realize that. Thank you as I probaby would have been going nuts looking for a throttle cut-off function.
BTW - I think your software is great and apologize for fumbling through it but I can say that most of what we do probably wouldnt be possible where it not for your software so I appreciate it and your help.
Regards
Pete

Thank you,
Scott

[Tomlin]

Yes, you said that already. What I asked was does it do the reverse, i.e. automatically enable the fuel when you push the levers off the stops? As I said, it seems a bit dodgy to me if it does...

BTW FS doesn't sport a control known as "throttle cut-off". You have to use Mixture Lean.

Regards

Pete

Pete, just for clarification since there are lots of new LJ45 projects that are springing up-

The Learjet 45 and 40 have the same TQ/Lever system. Scott was correct in the fuel cutoff and enable but maybe this will clarify just a bit since it works quite well in the real world and is very simple.

When ready for engine start, the crew simply push the levers forward and the cutoff pins drop into the idle spot. At that point the crew press the desired engine switch and start either 1 or 2.

When ready for shutdown, the levers are brought to idle, and then you pull up on the idle cutoff levers, located under the lever knobs. Then the levers are brought back to Cutoff and they shut down.

For those interested...

http://i159.photobucket.com/albums/t135/Tomlin242/TQcutoffdetent.jpg

BTW Pete, thanks for the reminder about 'Mixture Lean' for all the folks- that one got me about a while back.

[Peter Dowson]

When ready for engine start, the crew simply push the levers forward and the cutoff pins drop into the idle spot. At that point the crew press the desired engine switch and start either 1 or 2.

So, unlike airliners like the Boeings, the fuel flow is enabled BEFORE the engines are turning? I assume there must be an interlock some place that prevents the fuel valve actually opening causing wastage/flooding/fire risk?


When ready for shutdown, the levers are brought to idle, and then you pull up on the idle cutoff levers, located under the lever knobs. Then the levers are brought back to Cutoff and they shut down.

Ah, that's less dodgy than I thought, then -- there's a interlock to prevent accidentally cutting off when pulling back to idle.

Thanks for the clarification,

Pete

[Tomlin]

Right on with your statements- the start system for the LJ45/40 is Auto. The only thing you do after pushing the levers to idle is to press the Start button- it's all handled from there automatically. You dont even have to have the APU running, that's really only needed if the aircraft has been sitting overnight in a very cold environment, and then you might want an APU on just to warm the cabin up anyhow.

Thanks for your help in getting Scott back on the right path.

[XOrionFE]

Right on with your statements- the start system for the LJ45/40 is Auto. The only thing you do after pushing the levers to idle is to press the Start button- it's all handled from there automatically. You dont even have to have the APU running, that's really only needed if the aircraft has been sitting overnight in a very cold environment, and then you might want an APU on just to warm the cabin up anyhow.

Thanks for your help in getting Scott back on the right path.

Wow

Much easier than when I used to start P3's back in my Navy Flight Engineer days. APU or Air Start Cart for bleed air, direct to proper engine for start, turn on FF Valve, Press Start button, etc....