P3DV5.2 T-38A engines will not start

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redxfred
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Location: Strasburg, Virginia
P3DV5.2 T-38A engines will not start

Post by redxfred » Sat Aug 14, 2021 4:55 pm

This latest version of the T-38A Redux used to work well enough to fly using P3D V 5.1, but since upgrading Prepar3D to version 5.2, the engines will not light off. The start sequence seems to run as well as before the upgrade, but now Fuel flow and EGT remain at zero.

I have thousands of hours as a T-38A instructor so I can tell that something is amiss here...

The product is now useless as it stands.

JonathanBleeker
Posts: 3446
Joined: Sat Mar 13, 2010 7:38 pm
Re: P3DV5.2 T-38A engines will not start

Post by JonathanBleeker » Sun Aug 15, 2021 1:28 am

You sure you have fuel on board? Sometimes seen a quirk of P3D where the jet loads with zero fuel.

redxfred
Posts: 9
Joined: Wed Sep 28, 2011 1:54 am
Location: Strasburg, Virginia
Re: P3DV5.2 T-38A engines will not start

Post by redxfred » Mon Aug 16, 2021 7:01 pm

redxfred wrote:
Sat Aug 14, 2021 4:55 pm
This latest version of the T-38A Redux used to work well enough to fly using P3D V 5.1, but since upgrading Prepar3D to version 5.2, the engines will not light off. The start sequence seems to run as well as before the upgrade, but now Fuel flow and EGT remain at zero.

I have thousands of hours as a T-38A instructor so I can tell that something is amiss here...

The product is now useless as it stands.
Solved! My Milviz T-38A Redux will not start until the GPU air cart spins the Engine up to 20% RPM. The problem is that the GPU needs a tune-up... It fails to reach 20% on the first try. My work around is to start up again as soon as RPM decay is detected. Today it took three tries before the RPM hit 20%, at which time it started right up. Starting number two was automatic after number one started. It shouldn't be automatic, but it is.
Never mind how the actual airplane starts... 14% is minimum throttle-IDLE limit. EGT must rise within 12 seconds.

UPDATE 20221104 - This underspeed is fixed in my new install of P3Dv5.3 with the latest MILVIZ T-38A REDUX. I wrote a script for Thrustmaster Target Script Editor that starts the engines with a single switch press like the real thing:

MapKey(&Throttle, EOLIGN, CHAIN(PULSE+L_CTL+'1', D(60), PULSE+'q')); //Start Left Engine
MapKey(&Throttle, EORIGN, CHAIN(PULSE+L_CTL+'2', D(60), PULSE+'w')); //Start Right Engine

Change 1 & 2 to your starter commands, and q & w to your ignition commands. Good Luck!
Last edited by redxfred on Fri Nov 04, 2022 7:55 pm, edited 2 times in total.

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Slayer
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Re: P3DV5.2 T-38A engines will not start

Post by Slayer » Tue Aug 17, 2021 12:16 am

Thanks for offering your feedback. It may help someone else in the future. I'm not sure if the values you stated will get adjusted as that's not my call if/when this would get a tweak or if the values you offered are indeed correct. Will wait for JB to respond.


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