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How to set timer to run only at over say 25% (IC) throttle?


Jonathan M
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Apologies if this has been covered before, but I'm trying to work out how to set the timer for my IC models to only run when throttle is at say 20 or 25% or over.

 

It seems that I can set it to run at a percentage of total throttle - i.e. it'll count down slowly at lower revs and faster at higher revs - but this is not what I'm after.

 

In practice a few minutes can be spent after starting in the pits with the motor running at idle or slightly higher before I'm ready for takeoff (e.g. I might want to wait until someone has finished their schedule or messing about, or other models could be landing, or there could be a fulls-size overhead, etc).  Currently I tend to re-set the timer just before my own take-off, but sometimes forget.

 

Is there an easy way to set this?

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Not too sure of your Tx.

 

Can you set a switch to enable the timer, and then set the timer to run after the throttle is raised from tickover (theoretical low end throttle stop)?

That way you could keep your timer inactive while you start it and run it up and taxi to the flight line, then enable the timer, and as soon as you start increasing the throttle the timer starts.

 

My question to you would be - why bother?

If the engine is running it is using your fuel supply so that may as well be counted in your fuel consumption time.

If you extend the scenario you presented to extremes, you have your engine running for 5 or more minutes (because incoming planes are struggling to land in choppy weather for example), you then zero your timer (say 10 mins) before your plane takes off, you may find that you do not have 10 minutes fuel left in the tank meaning at some stage a deadstick landing is going to become a likelyhood.

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Good points Andy.  It isn't too much of a stress really because a typical full tank will give me 16-17mins and my timer is set to 12mins so there's normally plenty to spare even if I keep the engine running for a while at or slightly over tick-over (which in reality uses very little fuel).  The reason however that I prefer the timer to activate via the throttle is that avoids the problem of forgetting to hit a switch!

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12 hours ago, Allan Bennett said:

You can select a Logic state as the trigger for your timer, and then program the logic to change state when the throttle passes your desired percent.  Never tried it myself, so can't give line-by-line programming.

 

Yes, that's exactly the sort of thing I'm after.  But as I lack a skilled programming brain (and don't know if my version of TX and OpenTX will support this kind of intervention to the timer) I was hoping someone who'd already done this could provide an example of the programming!

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2 hours ago, Jonathan M said:

 

Yes, that's exactly the sort of thing I'm after.  But as I lack a skilled programming brain (and don't know if my version of TX and OpenTX will support this kind of intervention to the timer) I was hoping someone who'd already done this could provide an example of the programming!

 

This is a nice simple one that works on any version of OpenTX. Firstly set a logical switch for the desired throttle percentage - a full tutorial on logical switches is on OpenTX University (the section on a>x is ideal for your needs).

 

Once you have that single logical switch setup (if you have an additional throttle cut already setup set that as an auxilliary condition via the "AND" statement at the end of the logical switch line), then all you need to do is set up the timer to be triggered by it. Oscar Liang has a tutorial on that (though he is using an arming physical switch vs. a logical one the setup is exactly the same), here is the key screen:

 

timer-taranis-opentx-model-setup-arm-swtich.png

 

Painless360 also has content on this; though I haven't watched these specific videos his content is generally very good so I'm sure it will help:

 

 

 

 

Edited by MattyB
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Jonathan,

 

I use a button to turn on the timer for me whether it's electric or IC I'm flying.  This is part of my immediate pre-take off checks - so rate / condition switch correct, idle down (I have an idle setting for electrics that just keeps the motor running for landing) or up for IC and any mix switches selected and timer on.  It is a good habit to get into and one I borrowed from full size.

 

Likewise, I do a pre-landing check as I pass mid point on the downwind leg:  landing mode selected, mix switches out (I use a mix on elev triggered by closed throttle for a vertical downline and found out the first time I forgot to switch it off that closing the throttle completely as I flared for landing resulted in a nose down pitch!) and idle selected on (for electric powered models) and off for IC so I get the lowest idle.  Once you get into the habit you will be pleased you took the time to do so.  This will be particularly important for aircraft fitted with retracts and flaps of course!

 

Peter

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To help me, I have all the info set to voice alerts on the switch that activates the function, and on a switch that alerts me to the current state.  E.g. if I change the flaps (Switch B), I get a voice alert; if I change the undercarriage state (Switch A), I get a voice alert; my momentary switch H, will tell me the undercarriage position, flap position, timer(s), rx/flight pack voltage remaining.

 

On all models except my EDF's, my throttle controls the countdown flight timer, and 'adjusts' the time intervals dependant on throttle position.....  I think at a constant 25% throttle, the timer would take 20 minutes to countdown to zero, from 5 minutes. 

 

This is on my Radiomaster and X9D, both running OpenTX. 

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29 minutes ago, Peter Jenkins said:

Jonathan,

 

I use a button to turn on the timer for me whether it's electric or IC I'm flying.  This is part of my immediate pre-take off checks - so rate / condition switch correct, idle down (I have an idle setting for electrics that just keeps the motor running for landing) or up for IC and any mix switches selected and timer on.  It is a good habit to get into and one I borrowed from full size.

 

If it works for you that is fine and I am not suggesting any of your other pre-flight checks are not valid, but there is really no point in requiring a manual timer start if your TX is capable of automating it based on specific conditions (as any OpenTX and lots of other current transmitters can).

 

For instance, my X9D and TX16 both check that all switches are in the pre-defined correct positions for that model when the model is selected or the TX is switched on. When I enable the throttle it announces "Throttle activated, remember pre-flight checks", but I don't need to start the countdown timer - that is triggered automatically as soon as I advance the throttle beyond a certain point. Finally when I trigger the throttle cut the flight countdown timer is automatically reset to ensure I don't take off on the next flight without doing so. 

 

29 minutes ago, Peter Jenkins said:

Likewise, I do a pre-landing check as I pass mid point on the downwind leg:  landing mode selected, mix switches out (I use a mix on elev triggered by closed throttle for a vertical downline and found out the first time I forgot to switch it off that closing the throttle completely as I flared for landing resulted in a nose down pitch!) and idle selected on (for electric powered models) and off for IC so I get the lowest idle.

 

I don't know what TX you have, but can you not do all that on a single switch that selects the flight mode? It would certainly lower the workload on approach. Just a thought. 

Edited by MattyB
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Matty, I simply prefer doing it that way.  It can all be set on the condition switch on my Tx, JR XG11.  However, I prefer to have the mix available to be switched in or out for some manoeuvres - I'm flying the FAI(P) aerobatic schedule so the work load on landing is very light in comparison.  Depending on the approach obstacles I leave the idle off so that I can fly a steep approach over trees using the braking function.  Hence the reason for separate switches.

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5 hours ago, MattyB said:

For instance, my X9D and TX16 both check that all switches are in the pre-defined correct positions for that model when the model is selected or the TX is switched on. When I enable the throttle it announces "Throttle activated, remember pre-flight checks", but I don't need to start the countdown timer - that is triggered automatically as soon as I advance the throttle beyond a certain point. Finally when I trigger the throttle cut the flight countdown timer is automatically reset to ensure I don't take off on the next flight without doing so. 

 

That's the essence of it for me (except I don't have the throttle-activated voice alert as you do).

 

I do all my pre-flight checks in the pits before/after starting (i.e. the model checks), then do my pre-takeoff checks (i.e. check what else is in the air etc) once I've positioned the model on the strip and taken my position in the pilot-box.

 

That's enough for me - I don't want the timer on a switch, I want it on the throttle, but only over 25%.

 

Will get my head around the programming...

 

🙂

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13 hours ago, Jonathan M said:

That's the essence of it for me (except I don't have the throttle-activated voice alert as you do).

 

I do all my pre-flight checks in the pits before/after starting (i.e. the model checks), then do my pre-takeoff checks (i.e. check what else is in the air etc) once I've positioned the model on the strip and taken my position in the pilot-box.

 

That's enough for me - I don't want the timer on a switch, I want it on the throttle, but only over 25%.

 

Will get my head around the programming...

 

🙂

 

NP - Demo file (in OpenTX 2.3) attached, plus key screenshots below. The example has a very basic throttle cut that when it's enabled at the end resets the throttle timer for the next flight; I'd recommend you use a sticky throttle cut instead (example here), but the logic for the timer setup will be identical.

 

Setup screen:

image.png.f5e0f8bb85ebff294e5c6676206bf41c.png

 

Mixes screen:

image.png.3b6467f35e52518e133efed507d4cfec.png

 

Logical switches screen:

image.png.34a50aeb2a10c07ff01a23ad0a70ba3c.png

 

Special functions screen:

image.png.ee0285d47f0c8d868476d7ab1318f789.png

 

Sticky throttle cut example:

 

ThrTimer OTX 2.3.otx

Edited by MattyB
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23 hours ago, MattyB said:

 

NP - Demo file (in OpenTX 2.3) attached, plus key screenshots below. The example has a very basic throttle cut that when it's enabled at the end resets the throttle timer for the next flight; I'd recommend you use a sticky throttle cut instead (example here), but the logic for the timer setup will be identical.

 

Setup screen:

image.png.f5e0f8bb85ebff294e5c6676206bf41c.png

 

Mixes screen:

image.png.3b6467f35e52518e133efed507d4cfec.png

 

Logical switches screen:

image.png.34a50aeb2a10c07ff01a23ad0a70ba3c.png

 

Special functions screen:

image.png.ee0285d47f0c8d868476d7ab1318f789.png

 

Sticky throttle cut example:

 

ThrTimer OTX 2.3.otx 617 B · 1 download

 

Hi @Jonathan M... Did the above work for you? Any issues getting it setup?

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OK, np. To help I just added the sticky throtle cut to my example (it's the second model in the file), and also set both timers to reset on a after the throttle is disabled at the end of the flight; I've added a delay of 15 secs whcih should be ample to look down and check your flight time if you want to do that. Changes:

 

Mix screen (I've just changed the activating switch):

image.png.7034e8124fee305a29b9a8cbe5380898.png

 

Logical switches (L03 does the sticky throttle cut, L04 triggers the timer resets 15 secs after activating throttle cut):

image.thumb.png.ee47c977b71cb80591bc6edef5986637.png

 

Special Functions (one additional line to trigger the reset of the Flt timer):

image.png.fb74baa8026973a57e3562c92b5ec8eb.png

 

ThrTimer OTX 2.3 v2.otx

Edited by MattyB
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I've got it now!  Thanks so much Matty.

 

As I only use Companion for backup purposes, I've done it all on the TX, which I much prefer as I can make changes at the field etc.  Also I've only dealt with the timer being activated over 25% throttle as per my original quest.  Re-setting the timer I always do via the menu button on the TX, as this is how I deal with all my flying - thermal soaring as well as FW power - so don't want to have two different methods or I'll wind up getting confused!

 

The photos below present the order in which I tweaked the programming.  The reason for this order is that there are no Logical Switch options on the Timer 1 line on the Model Setup page until one is actually set up first in the Logic Switch menu page!

 

(1) Throttle mix is only ever active when SB is in the UP position, otherwise the output is held at -100, i.e. no throttle output at all, called here ThrHld.  (This was already programmed in all my power models.)

 

PXL_20211126_115723748.thumb.jpeg.09178f896ef8558e8fe69b3f9928ef99.jpeg

 

(2) A Logical Switch (LO1) was programmed to be TRUE (i.e. 'on' )when the throttle is above 25% (the range is -100 to +100) AND switch SB is in the top position.

 

PXL_20211126_115701574.thumb.jpeg.64d03971c01057d639338e1e7084481f.jpeg

 

(3) Note that in the above Logical Switch programme line I could have chosen either the physical Throttle Stick or the Throttle Input, as the relationship between the two is entirely linear, i.e. 100% Stick = 100% Input, and this is also reflected in the Mixer line for throttle in the first photo above.  (This won't be the case for the other mixes for this model - i.e. aileron, elevator and rudder - but I've yet to actually programme the desired surface travels in the Mixer Page and tweak the Expo in the Inputs Page for this new model.)

 

PXL_20211126_115752691.thumb.jpeg.d19ec70e4593ec96975b4994d3b830d8.jpeg

 

(4) Finally I could then go to the Model Setup page and find Logical Switch LO1 (now that it's been programmed in!) to trigger the countdown timer.

 

PXL_20211126_115811073.thumb.jpeg.fd6f115f43f695c805c1acd8aca594ff.jpeg

 

Physically the thing looks like this:

 

PXL_20211126_115535579.thumb.jpeg.02e09758f2944c5bafadf57943993099.jpeg

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NB  I'm now using the above sequence of photos as an aide-memoire to myself to programme the same on my other IC models.

 

But as in some of these the Throttle Input does not equal physical Throttle Stick travel (e.g. 100% travel = 60% Input on my Boomerang), it's now clear that the Logic Switch must be based on the physical Throttle Stick travelling 25%, else the timer won't cut in until higher throttle Input (i.e. 25/60 = 42% throttle)!

 

This is the correct way it should look:

 

PXL_20211126_130850464.jpeg

 

 

Edited by Jonathan M
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4 hours ago, Jonathan M said:

I've got it now!  Thanks so much Matty.

 

As I only use Companion for backup purposes, I've done it all on the TX, which I much prefer as I can make changes at the field etc.  Also I've only dealt with the timer being activated over 25% throttle as per my original quest.  Re-setting the timer I always do via the menu button on the TX, as this is how I deal with all my flying - thermal soaring as well as FW power - so don't want to have two different methods or I'll wind up getting confused!

 

Great good stuff. Re: Companion, yes it is always useful to be able to setup via the TX, but if you really want to use the power of OpenTX is can be hard work on the transmitter, especially ifit isn't a touch enabled TX. Personally I always setup on Companion initially as it's just so much faster that way and I won't wear ou the (now slightly sketchy) buttons on my old X9D!

 

4 hours ago, Jonathan M said:

(3) Note that in the above Logical Switch programme line I could have chosen either the physical Throttle Stick or the Throttle Input, as the relationship between the two is entirely linear, i.e. 100% Stick = 100% Input, and this is also reflected in the Mixer line for throttle in the first photo above.  (This won't be the case for the other mixes for this model - i.e. aileron, elevator and rudder - but I've yet to actually programme the desired surface travels in the Mixer Page and tweak the Expo in the Inputs Page for this new model.)

 

Yes, that is a good point - logical switches based on stick positions need to use the native stick position parameter, not the one washed through the Inputs screen marked [I]. 

 

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