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HOBBS 'Flight Time' gauge question

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10,088
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us-arizona
Hey guys,

How does one link a 'flight time' HOBBS timer? Is there a code that is 'in flight' that I dont know about? Or does one create a 'trigger' to activate the timer based on some trick code, like 'actual alt is greater then 1 foot', or 'airspeed is greater then 70 knots'.

Many thanks,


Bill
 
Messages
1,614
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puertorico
Thanks... the planes I usually fly don't need that sort of fancy instrumentation ....


Now, for the real question that I wonder, for what model is that Hobbs timer being worked on?
 

n4gix

Resource contributor
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11,674
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unitedstates
Hey guys,

How does one link a 'flight time' HOBBS timer? Is there a code that is 'in flight' that I dont know about? Or does one create a 'trigger' to activate the timer based on some trick code, like 'actual alt is greater then 1 foot', or 'airspeed is greater then 70 knots'.

Many thanks,


Bill

You might try something really radical...

...open the SDK and check the list of available variables for XML gauges:

(A:GENERAL ENG ELAPSED TIME:n*,hours)........Total engine elapsed time

* NOTE: where n is the engine number, 1, 2, 3, 4

Both FS9 and FSX keep a file in the User's Application Data area called "state.cfg"...
 
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10,088
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us-arizona
Hey Fr. Bill,

This is an actual 'in flight' HOBBS. I have heard of them, but dont know of a way to trigger its 'in flight' mode.

There are two on this bird, one for engine time, and the other for flight time. (How it knows to do this, I dont know). There is no visible key button on the HOBBS for 'flight time', so it doenst appear to be triggered manually by the pilot.


Hey Felix,

This is a revamp of the Kodiak interior/panel, then conversion to FSX format. (The model will be for both FSX and FS9).
 
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Messages
1,243
Country
canada
It could be using flight hobbs time based on a pressure switch in the nose gear (guess). Lift-off nose gear extends and you have flight time. So your greater than 1 foot idea might be it.

Engine Hobbs time is based on oil pressure - ie engine running.

Usually Hobb's is connected to the master switch but some say on rentals people have switched off the master to save money. (find that hard to believe)
 
Messages
18
Country
luxembourg
As for real planes I could imagine the timer being started by sensing the load/pressure on the undercarriage dissappearing/going negative.

As the plane rises the undercarriage is no longer being compressed but starts to hang from the aircraft (negative value) the timer would autostart whenever the pressure is 0 or less, meaning there is no aircraft propping it's weight on the undercarriage.

This would essentially give you only actual time in flight (not touching ground)

But on how to do this in Flight Sim?

Maybe you can use PLANE ALT ABOVE GROUND
If I understand it correctly this will give you your altitude relative to the ground so an airport at 150 ft won't trigger the "you are in flight timer" just because your altitude according to air pressure is 150ft.

If it doesn't work like that you could make an equation deducting ground level from current altitude to let it know if it's on the ground or not.

I hope I understood your question correctly. I'm too busy myself to add this to my flight test gauge to see if PLANE ALT ABOVE GROUND will simply say 0 when you are on the ground or if the "sensor" is at fuselage height.

Unless I misunderstood you my guess would be such a "sensor" as trigger would work well.

Good luck!
Luggage

EDIT

woops yes you are right DNLK, overlooked it when I was looking at what variables could be used for this.
I kind of like the small deviation factor my idea would give, sense of realism. But your solution is of course perfect for this.
 
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Horst18519

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2,369
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germany
I'm currently working on an RPM gauge and thus know how they did in in its real world alter ego. When the RPM exceeds 2000 for more than 10 seconds (which it will most probably on takeoff) the Flight Timer starts. When RPM drops below 1000 (or whatever) for more than 20 seconds (which will most probably only happen after touchdown) the timer stops.

Bill's suggestion is quite good too, though. It's very nice to use the variable stored in the state.cfg.
 

n4gix

Resource contributor
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11,674
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unitedstates
Interesting, Bill. The Oxygen control is identical to the one used in the Columbia (now Cessna) 400...

The "engine working time" HOBBS can simply use the state.cfg file to keep life simple.

The "flight time" HOBBS will have to be custom coded to keep track of accumulated flight time. Real a/c use a "squat switch" usually on the left main to determine WOW (weight on wheels). If the switch is open, then you must be airborne (or falling off a cliff)... ;)

As already mentioned, the (A:AIRCRAFT ON GROUND,bool)is what would be used to emulate the "squat switch..." :D

Unfortunately, XML script provides no way to 'store the accumulated time,' so it's pretty useless for your purpose.

I will gladly provide you with a small C gauge "Hobbs" that will suit your purpose, and will of course save the time to a tiny .dat file.
 
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10,088
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us-arizona
Interesting, Bill. The Oxygen control is identical to the one used in the Columbia (now Cessna) 400...

The "engine working time" HOBBS can simply use the state.cfg file to keep life simple.

The "flight time" HOBBS will have to be custom coded to keep track of accumulated flight time. Real a/c use a "squat switch" usually on the left main to determine WOW (weight on wheels). If the switch is open, then you must be airborne (or falling off a cliff)... ;)

As already mentioned, the (A:AIRCRAFT ON GROUND,bool)is what would be used to emulate the "squat switch..." :D

Unfortunately, XML script provides no way to 'store the accumulated time,' so it's pretty useless for your purpose.

I will gladly provide you with a small C gauge "Hobbs" that will suit your purpose, and will of course save the time to a tiny .dat file.

Hey Bill,


So you figured a way to save the time 'in flight' to a DAT file? Ingenious...! I had totally forgotten that the time is saved on the aircrafts log file and that 'another one' would be next to impossible to aquire/create/log.

I'll email you about the gauge.

You guys really amaze me on how you work around constraints. The sky is certainly not the limit.

Many thanks,


Bill
LHC
 
Messages
516
The aircraft I'm coding saves lots of statistics to a dat file. I test for SimOnGround to establish flying hours, but I also test for Slew mode or Pause time and discount that.

Si
 
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10,088
Country
us-arizona
Impressive.. So yours is 'absolute' flight time.

You guys dont leave out any possibilities, do you.

:D


Bill
 
Messages
18
Country
luxembourg
I don't know I guess I'm weird I would have made something more deliberate that might miss a few seconds flight time now and then. Imperfect like the real world. :)

Pity there is no pressure on the undercarriage variable. I think that's how they would do it in real life, simple pressure switch seeing as there is pressure on it when on the ground with the fuselage weight on the undercarriage and no pressure when airborne since then the undercarriage hangs from the fuselage.

But like I said I'm weird and the best option I guess is to simply query the sim on ground variable.

luggage is a bit strange :D
 

Horst18519

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2,369
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germany
You can check if the pressure is on by checking if the gear damping is at more than 0%. ;)

But this actually is the same as ON GROUND. :D
 
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