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Author Topic: Engine surge during jet engine start  (Read 4614 times)

Offline Mach7

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Engine surge during jet engine start
« on: September 28, 2013, 10:04:37 AM »
I know this is a flight sim thing...but is there anyway around the unrealistic engine 'surge; of N1 and N2 during a jet engine start in fs9.

there must be a patch to fix this?

Offline jackpilot

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Re: Engine surge during jet engine start
« Reply #1 on: September 28, 2013, 05:15:16 PM »
You need an avionics soft on top of FS, (PM SimA Prosim etc..) which allows slowing down spool up and adjusting the N1 N2 sequence.
I doubt you can modify stock FS.
Jack


Jack

Offline Mach7

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Re: Engine surge during jet engine start
« Reply #2 on: September 30, 2013, 09:27:06 AM »
Thanks jackpilot...guess i will just have to live with it.

Offline jackpilot

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Re: Engine surge during jet engine start
« Reply #3 on: September 30, 2013, 05:02:22 PM »
Maybe a LUA using FSUIPC could do it.
Maybe David (FordGT40) or Mike would know
Guys? ::)


Jack

Offline fordgt40

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Re: Engine surge during jet engine start
« Reply #4 on: October 03, 2013, 04:47:32 AM »
Jack

I am away for a few days, but will think about it. If the OP could specifically define what is wrong, eg wrong sound wav, timing, sequence etc, it would help

David

Offline jackpilot

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Re: Engine surge during jet engine start
« Reply #5 on: October 03, 2013, 11:26:35 AM »
James

Please keep contact with David on that
Pretty sure he can find a way!...lol
Jack


Jack

Offline Mach7

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Re: Engine surge during jet engine start
« Reply #6 on: October 04, 2013, 03:59:20 PM »
Guys, thanks for taking the time to look at my problem.

Here is a link to my engine start video (tried to download it here but the file was too big).

http://s794.photobucket.com/user/Mach73/media/BAe146_gauges/001.mp4.html?sort=3&o=0

Dave, as you can see I am trying to eliminate or reduce the N1 and N2 surging past the ground idle values during engine start, that is to say they should accelerate normally to 26 percent and 51 percent repectively.

I know this is an inherent Fs9/X thing, and also realize that some simulator platforms (payware) have probably solved this problem, but was wondering if there is something I can do at this end to fix this.

Thanks again for any input

-Jim

Offline Mach7

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Re: Engine surge during jet engine start
« Reply #7 on: October 04, 2013, 04:01:43 PM »
Also...sorry for the video quality, starting from the top the gauges are as follows, Oil temp/press, N1, TGT, N2, and Fuel flow (WF).

Offline fordgt40

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Re: Engine surge during jet engine start
« Reply #8 on: October 06, 2013, 04:27:23 AM »
Jim

What software are you using to drive the gauges?
If it is SIOC, could you post the script

Jack

No pressure then  :D

David

Offline Mach7

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Re: Engine surge during jet engine start
« Reply #9 on: October 06, 2013, 08:15:44 AM »
David,

I am using SIOC.

Here are two of the scripts, one for Engine 1 N1 and the other for Engine 1 N2;

// *****************************************************************************
// * Config_SIOC ver 4.01   -     By Manuel Velez    -    www.opencockpits.com
// *****************************************************************************
// * FileName : EngineGauges.txt
// * Date : 05/03/2012



Var 0001, name Eng1N1, Link FSUIPC_IN, Offset $0898, Length 2     // Engine1 N1
{
  L0 = &Eng1N1 / 164     //  Scales to 0-100%     
  L1 = L0 * 5.24
  L2 = 314 + L1
  &Eng1n1servo = L2   
}

Var 0002, name Eng1n1servo, Link USB_SERVOS, Output 1, PosL 314, PosC 576, PosR 838




// *****************************************************************************
// * Config_SIOC ver 4.01   -     By Manuel Velez    -    www.opencockpits.com
// *****************************************************************************
// * FileName : EngineGauges.txt
// * Date : 05/03/2012



Var 0017, name Eng1N2, Link FSUIPC_IN, Offset $0896, Length 2     // Engine1 N2
{
  L0 = &Eng1N2 / 164     //  Scales to 0-100%     
  L1 = L0 * 5.37
  L2 = 322 + L1
  &Eng1n2servo = L2   
}

Var 0018, name Eng1n2servo, Link USB_SERVOS, Device 1 Output 3, PosL 322, PosC 591, PosR 859


Offline fordgt40

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Re: Engine surge during jet engine start
« Reply #10 on: October 06, 2013, 08:26:30 AM »
Jim

Thanks, I have family here at present, but will look at this later

David

Offline fordgt40

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Re: Engine surge during jet engine start
« Reply #11 on: October 07, 2013, 11:56:31 AM »
Hi Jim

I have had a look at the problem. Given that we cannot get into FS then we need to look at the sioc coding for the gauges to see if we can limit the

needle movement so that the "surge" is not reflected by the needle.

If we create a variable called startup and set this to 1 when the code is first run, then we can use this as a flag to see whether we need to limit the

needle movement; eg if we are in "startup" mode or not.

We can then insert some code into each engine/gauge code so that the needle movement is limited, but only when in "startup" mode.
Suggested code changes are: -

// *****************************************************************************
// * Config_SIOC ver 4.01   -     By Manuel Velez    -    www.opencockpits.com
// *****************************************************************************
// * FileName : EngineGauges.txt
// * Date : 05/03/2012


Var 0, value 0
{
&startup = 1 / flag set to 1 to show we are in startup mode, only use this code once at the beginning of your script
}


Var 10, name startup

Var 0001, name Eng1N1, Link FSUIPC_IN, Offset $0898, Length 2     // Engine1 N1
{
  L0 = &Eng1N1 / 164     //  Scales to 0-100%     
  L1 = L0 * 5.24
  L2 = 314 + L1
  IF &startup = 1
   {
   IF L2 > xxxx / you need to set this value of xxxx so that the needle relfects the correct idle position
      {
      L2 = xxxx
      }
   }

  &Eng1n1servo = L2   
 
}

Var 0002, name Eng1n1servo, Link USB_SERVOS, Output 1, PosL 314, PosC 576, PosR 838

This code if unchanged will keep the startup flag as 1 and will not allow the gauge to move beyond idle value. You therefore need to use another

variable to reset the startup flag back to 0. A suggestion could be to include a line of code that recognises when the throttle lever is moved beyond idle

position, then you can reset the startup flag back to 0 and the gauges will be free to move.

This is simple untested code, which should work, I hope, but will need to be amended if you want the sophisticated functions of engine restart in flight

etc  :)

Hope this helps, any queries then just ask

David
« Last Edit: October 07, 2013, 03:15:08 PM by fordgt40 »

Offline Mach7

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Re: Engine surge during jet engine start
« Reply #12 on: October 07, 2013, 03:24:29 PM »
David,

Thank you very much for this...when I get home from my pairing I will try the code out and let you know...i might have some questions before hand.

-Jim

Offline jackpilot

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Re: Engine surge during jet engine start
« Reply #13 on: October 11, 2013, 08:29:47 PM »
David

When I met you at the FDS open house you looked like a normal human being.
The way you can figure out  that SIOC stuff out makes me think you're not :laugh:
Thanks for the help.
PS I sent your breakers in the US


Jack

Offline fordgt40

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Re: Engine surge during jet engine start
« Reply #14 on: October 12, 2013, 05:42:04 PM »
Jack

Thanks for the CB dispatch - I still owe you!
We have not heard from Jim yet, so the code may not have worked - quite common first time  :)

Don`t worry, I think I am quite normal, or at least as the Mythbusters say " I introduce my own reality"
Whilst I can programme, of sorts, copious amounts of alcohol, good food and bad women are also very welcome and a necessary addition

Is that more normal  :)

David

Offline jackpilot

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Re: Engine surge during jet engine start
« Reply #15 on: October 13, 2013, 08:00:51 AM »
I'm with you ! ;)


Jack

Offline Mach7

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Re: Engine surge during jet engine start
« Reply #16 on: October 18, 2013, 08:52:44 PM »
Hello David and Jackpilot,

Just to update you, I have not had much time to run the program but am planning to do it on one gauge only to see how it works...assuming I can get the SIOC program to compile "OK".

My only concern is with the gauge itself...I am using the actual potentiometer from the actual gauge and if the gauge goes off the scale...i have to unfortunaltley remove the gauge...take it apart, and manually move the needle so the pot contacts are back within there operating range.

i don't anticipate any problems..but will test it out on one gauge first then see what happens..

will keep you updated..

thanks for thinking about me:)

 

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