Runaway Turboprop starting...

[birdguy 3,943]

I've been fighting this for years with my Quest Kodiaks from FSX through P3Dv4.  I finally reverted to startup scenarios with the engine already running.  But I think I found a solution to the startup problem.  Not perfect, but so far it works.

Set your parking brake on.  Advance the throttle about a quarter of the way up.  Set the fuel conditioner to off.  Turn on the starter and as soon as NG gets to about 5 or 6 slowly advance the fuel conditioner until you see the puff of smoke in front of the cowling and leave it there.  When the torque starts rising bring the throttle all the way back.  It still strains a bit on the parking brake but it doesn't 'run away' leaving skid marks on the tarmac...SO FAR.

I have been using this technique for about a month now.  I have no idea if this will work on other turboprops or not since I only fly the Kodiaks.  But it's worth a try.

Noel 

Edited June 16, 2019 by birdguy

[thibodba57 462]

1 hour ago, birdguy said:

I've been fighting this for years with my Quest Kodiaks from FSX through P3Dv4.  I finally reverted to startup scenarios with the engine already running.  But I think I found a solution to the startup problem.  Not perfect, but so far it works.

Set your parking brake on.  Advance the throttle about a quarter of the way up.  Set the fuel conditioner to off.  Turn on the starter and as soon as NG gets to about 5 or 6 slowly advance the fuel conditioner until you see the puff of smoke in front of the cowling and leave it there.  When the torque starts rising bring the throttle all the way back.  It still strains a bit on the parking brake but it doesn't 'run away' leaving skid marks on the tarmac...SO FAR.

I have been using this technique for about a month now.  I have no idea if this will work on other turboprops or not since I only fly the Kodiaks.  But it's worth a try.

Noel 

Have you tried starting the engine in feather only?  I seemed to have success with that with the Iris PC-9.

Throttle idle, Props all the way in Feather, Condition lever low idle at 15% N2.  Starter off the moment ignition occurs and just wait. You'll see the EGT roll back. That's when to slowly bring the props forward.

Edited June 16, 2019 by thibodba57

[FDEdev 955]

Interesting. Both of the described methods aren't used IRL and aren't suitable in the sim either.

1. Power lever idle in any case.

1. On most, (if not all) PT6 equipped planes like the Kodiak and the PC-9, you start the engines with the propeller in the feathered position.

2. You should move the condition lever from idle to min at max motoring RPM, which happens in FSX/P3D at approx 12%.

3. Don't turn off the starter too early. Either it disengages automatically when reaching idle, or if not, wait with disengaging until the engine is stabilized at idle.

4. You can/should leave the prop in feather until you are ready to taxi.

Btw, if the P3D FDE is a high quality one (or has been updated since P3D v3), engine spool up during start will be realistically slow, with no significant RPM and/or torque overshoot.

You theoretically don't even need the brakes (although it's of course required if you follow the procedures) since there's no power surge.  

Edited June 16, 2019 by FDEdev

[thibodba57 462]

7 hours ago, FDEdev said:

Interesting. Both of the described methods aren't used IRL and aren't suitable in the sim either.

1. Power lever idle in any case.

1. On most, (if not all) PT6 equipped planes like the Kodiak and the PC-9, you start the engines with the propeller in the feathered position.

2. You should move the condition lever from idle to min at max motoring RPM, which happens in FSX/P3D at approx 12%.

3. Don't turn off the starter too early. Either it disengages automatically when reaching idle, or if not, wait with disengaging until the engine is stabilized at idle.

4. You can/should leave the prop in feather until you are ready to taxi.

Btw, if the P3D FDE is a high quality one (or has been updated since P3D v3), engine spool up during start will be realistically slow, with no significant RPM and/or torque overshoot.

You theoretically don't even need the brakes (although it's of course required if you follow the procedures) since there's no power surge.  

The procedures above are to mitigate a sim induced surge.  Don't know what the cause is, but I've seen it take an aircraft with the parking brake on and go 0-60 in the blink of an eye.  

I have 5000 hrs flying the PT-6. I'm more than aware of how to operate one.  But when the sim doesn't cooperate you do what you have to do.  

Not all PT-6s are started in the same manner btw.  The Be-1900C the prop levers were advanced to full forward prior to start, the D models however remained in feather. Max N2 motoring is closer to 20% and the condition lever is place into the Low Idle position not Min.

[birdguy 3,943]

I tried both Brian and FDEdev starting methods.  With both I get the surge and go through a hangar door and the fence with the brakes on with the Kodiak.

Noel

[FDEdev 955]

1 hour ago, thibodba57 said:

1. Max N2 motoring is closer to 20%.

2. The condition lever is place into the Low Idle position not Min.

1. Again, not in FSX/P3D

2. Well, whatever is the lowest in FSX/P3D. This position can be far below low idle etc.

To achieve the absolute minimum fuel flow you should advance the condition lever very slowy (after reaching 12%) until ignition occurs, which happens without delay in FSX/P3D.

That's the only variable which affects the surge on startup. 

If you have P3Dv3 or higher you can apply the necessary startup modifications for a realistic startup on your own (plus you get a more realistic, faster engine response during normal ops). 

 

 

Edited June 17, 2019 by FDEdev