Jump to content
Sign in to follow this  
JesC

EGT Yellow Arc

Recommended Posts

Does anyone know what the yellow arc on the EGT gauges represents? I haven't been able to come up with any information on them.

Thanks,

Jesse


Jesse Cochran
"... eyes ever turned skyward"

P3D v5.3 Professional, Windows 10 Professional, Jetline GTX, Gigabyte Aorus X299 Gaming 7 mobo, i7 7740X @ 4.9 GHz, Corsair H115i Liquid Cooling, 32Gb SDRAM @ 3200MHz, Nvidia GeForce GTX1080Ti @ 11 GB

ORBX Global + NALC, ASP3D, ASCA, ENVTEX, TrackIR, Virtual-Fly Yoko Yoke, TQ6+, Ruddo+ Rudder Pedals

Share this post


Link to post
Share on other sites

Perhaps I should clarify. I am asking about this because I have always recognized a yellow arc marking on any gauge to be a caution zone. But in the 690 I find myself operating within this apparent caution area in many flight regimes even with moderate power settings. And in fact there is quite a separation between these temps and the red line implying that it is satisfactory to operate at temps higher than the caution area. Very confusing. So I thought there may be more to the explanation.

At any rate, If anyone has some knowledge of this I would sure like to hear your explanation.

Thanks,

Jesse


Jesse Cochran
"... eyes ever turned skyward"

P3D v5.3 Professional, Windows 10 Professional, Jetline GTX, Gigabyte Aorus X299 Gaming 7 mobo, i7 7740X @ 4.9 GHz, Corsair H115i Liquid Cooling, 32Gb SDRAM @ 3200MHz, Nvidia GeForce GTX1080Ti @ 11 GB

ORBX Global + NALC, ASP3D, ASCA, ENVTEX, TrackIR, Virtual-Fly Yoko Yoke, TQ6+, Ruddo+ Rudder Pedals

Share this post


Link to post
Share on other sites

Jesse,

First, let me explain what Carenado has modeled.  The airplane is a 690B, however it was modified to carry TPE-331-10 engines.  The -10 engines use EGT gauges vice ITT gauges because the "bigger" engines ran so hot that normal thermocouples were not available to measure ITT.  So, they used the cooler running EGT instead, measured at the exhaust of the final turbine stage.  The most similar factory airplanes that used EGT were the 980 and 1000 versions.  I have a Pilot Operating Handbook for the 980 and it does not address the yellow arc on the EGT gauge at all.  The starting limit is 770 and otherwise the limit is 650.  Those may or may not be the actual physical temperatures and the measurement points.  The system uses a computer that considers ambient temp, pressure, back-pressure to compute a SRL (single red line) value for EGT.  The gauge indication is then corrected for those factors.  The pilot only has to remember the 650 maximum (or 770 for start, but that is actually marked on the gauge).

I know that doesn't help, but apparently the yellow arc has no meaning.  Or at least not enough meaning to mention it in the POH.

I've got a fairly major redo of the 690B in work.  

Regards,

Bill   

Share this post


Link to post
Share on other sites

Hi Bill.

Thanks for taking the time to post the comprehensive information. It's all right in line with what I have been able to find, also. And that's after considerable digging around.

Still hoping that some reasonable explanation will present itself at some point. Sure makes nervous flying around with a gauge so regularly indicating in what appears to be a caution range; even if it is just a simulation. 🙂

Also, looking forward to your mod updates.

Jesse


Jesse Cochran
"... eyes ever turned skyward"

P3D v5.3 Professional, Windows 10 Professional, Jetline GTX, Gigabyte Aorus X299 Gaming 7 mobo, i7 7740X @ 4.9 GHz, Corsair H115i Liquid Cooling, 32Gb SDRAM @ 3200MHz, Nvidia GeForce GTX1080Ti @ 11 GB

ORBX Global + NALC, ASP3D, ASCA, ENVTEX, TrackIR, Virtual-Fly Yoko Yoke, TQ6+, Ruddo+ Rudder Pedals

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

  • Tom Allensworth,
    Founder of AVSIM Online


  • Flight Simulation's Premier Resource!

    AVSIM is a free service to the flight simulation community. AVSIM is staffed completely by volunteers and all funds donated to AVSIM go directly back to supporting the community. Your donation here helps to pay our bandwidth costs, emergency funding, and other general costs that crop up from time to time. Thank you for your support!

    Click here for more information and to see all donations year to date.
×
×
  • Create New...