Blackbird Sims / Milviz Forum Archive

Hi guys,

Observation: even though I fly the PC6 within margins, I see the engine degradation level decrease dramatically in MVAMS over several flights.
After a flight of 2-3 I can even get engine failure, while still flying her within safety margines, so it's not just graphical feedback from MVAMS:
the engine is actually degrading way fast!

Is there something I could be doing wrong in this regard?
It seems strange to me that an engine with a real life HSI of 1800 and TBO of 3600 hours would barely make 5-6 hours before doing POOF.

Same observation. Even to the point of engine failure, exit sim, open mvams and it shows solid green line. Something is amiss. This plane is a workhorse IRL and keeping within limits seems to have no effect. But other than the kid gloves with the engine, I am very happy with the porter.

Win7 and the trial SP

Hmm, i'm seeing low red line in mvams within several hours. So so far i can see the mvams state work correctly with actual engine state in sim, not what you describe.

Hi,

Normal engine wearing in the Porter is 1 % per flight hour (engine running), so engine tolerance is 100 hours free of events.
In addition to normal wearing, engine health is affected by exceedances in ITT, Torque, N1 and Oil Temp limits.
Every time a digital readout flashes there is a penalty to the engine status. Considering that, a good handling should allow for at least 50 hours before the engine may fail (50 % of basic life without any incident).

Tomas

Hi... same observation here... no flashing... within limits for sure... handled with care like a box of eggs... mvams degrading fast... and even more somtimes on a reload its completely messed up and red. It seems to degrade waaay to fast and not consistent all the time.

Cheers
Thorsten

Taguilo wrote: ↑

Wed Jun 26, 2019 7:27 pm

Hi,

Normal engine wearing in the Porter is 1 % per flight hour (engine running), so engine tolerance is 100 hours free of events.
In addition to normal wearing, engine health is affected by exceedances in ITT, Torque, N1 and Oil Temp limits.
Every time a digital readout flashes there is a penalty to the engine status. Considering that, a good handling should allow for at least 50 hours before the engine may fail (50 % of basic life without any incident).

Tomas

Thanks for the feedback. But i never get numbers in the blinking phase, except on startup, which I don't seem to be able to circumvent.
Tips?

Tobus wrote: ↑

Wed Jun 26, 2019 8:19 pm

Thanks for the feedback. But i never get numbers in the blinking phase, except on startup, which I don't seem to be able to circumvent.
Tips?

If you have problems at startup, then you can try by checking the custom Autostart (CTRL-E). Pay attention to the sequence followed and try to replicate that in your own starts.

Here are some advices for a cool start:

-Power Lever ALWAYS in idle position.
-Turn On Fuel Pump and Ignition before switching the Starter to ON.
-After cranking the starter, wait until Gas generator RPM reaches 18 % or above. Then move CL to Low idle.
-NEVER move the CL to Low/High Idle before cranking the starter, or when RPM are below 10-12 %
-As soon as Gas Gen RPM stabilizes at ~52-53 % cut the starter and the ignition. Do not forget starter running or you will overtemp and probably damage the battery.
-Do not start the engine just after a shut down ,when ITT is still high. Wait some time until ITT decreases to reasonable values, below 200 C.
If you need to, run the starter alone respecting starter periods of 30 secs on/2 min off, etc. until ITT reaches a safe temp for starting.

Hope this helps

Tomas

Thorsten42 wrote: ↑

Wed Jun 26, 2019 8:02 pm

Hi... same observation here... no flashing... within limits for sure... handled with care like a box of eggs... mvams degrading fast... and even more somtimes on a reload its completely messed up and red. It seems to degrade waaay to fast and not consistent all the time.

Cheers
Thorsten

I wasn't able to replicate the MVAMS messing issue that you describe. If it happens again please let us know, and try to describe as much as possible the steps for that situation.

Thanks

Tomas

Taguilo wrote: ↑

Wed Jun 26, 2019 8:58 pm

If you have problems at startup, then you can try by checking the custom Autostart (CTRL-E). Pay attention to the sequence followed and try to replicate that in your own starts.

Here are some advices for a cool start:

-Power Lever ALWAYS in idle position.
-Turn On Fuel Pump and Ignition before switching the Starter to ON.
-After cranking the starter, wait until Gas generator RPM reaches 18 % or above. Then move CL to Low idle.
-NEVER move the CL to Low/High Idle before cranking the starter, or when RPM are below 10-12 %
-As soon as Gas Gen RPM stabilizes at ~52-53 % cut the starter and the ignition. Do not forget starter running or you will overtemp and probably damage the battery.
-Do not start the engine just after a shut down ,when ITT is still high. Wait some time until ITT decreases to reasonable values, below 200 C.
If you need to, run the starter alone respecting starter periods of 30 secs on/2 min off, etc. until ITT reaches a safe temp for starting.

Hope this helps

Tomas

Thanks Tomas, I'll try this to the letter and see if problems persist or root cause was/is between the chair and the desk

Taguilo wrote: ↑

Wed Jun 26, 2019 9:13 pm

I wasn't able to replicate the MVAMS messing issue that you describe. If it happens again please let us know, and try to describe as much as possible the steps for that situation.

Thanks

Tomas

Thx Tomas

Yeah I wasn't able to reproduce up to now for documentation... perhaps a gremlin... if I encounter it again I will give as much info as possible.
Currently flying in PNG with high oat temps at high altitude and it is so much fun to keep the engine in the green. Brilliant model. And following your tips on starting reducing temps at start... on a second start after cooling down to below 200 deg c it still peaks above red but not flashing. I hope thats ok.

Cheers
T.

Thorsten42 wrote: ↑

Thu Jun 27, 2019 8:48 am

[... on a second start after cooling down to below 200 deg c it still peaks above red but not flashing. I hope thats ok.

Yes, it is correct. In the start process ITT tolerance is greater than in normal flight, so you will notice that the gauge shows a second red line around 1000 deg Celsius. That is a startup limit. This said, the coolest you manage your engine the longer it will last before an overhaul.

Tomas

Hi Tomas,

seeing your point by point description I see some discrepancies/missing stuff in the manual.
Also, is it flown with the CL moved all the way forward, or just in the yellow band (high idle)?
I'm used to putting it forward before take off, but now think I'm setting it too high maybe?

Tobus wrote: ↑

Thu Jun 27, 2019 7:41 pm

Hi Tomas,

seeing your point by point description I see some discrepancies/missing stuff in the manual.
Also, is it flown with the CL moved all the way forward, or just in the yellow band (high idle)?
I'm used to putting it forward before take off, but now think I'm setting it too high maybe?

Usually CL is placed in Low Idle position at startup,as to obtain a smooth transition between start and idle N1 rpms. Once in idle (above 52 % N1) you can put it in High Idle for taxi or move it from Low Idle to a bit below High Idle in hot weather to cool the engine.
Leaving it in High Idle will not produce a negative effect as long as ITT limits are respected.

Tomas

Hi Tomas,

ok copy on the CL.

I've started some testing, mostly to find out about my own fault regarding this cool bird.
Setting: Engine reset in mvams, go to PNG, hot and high density alt, short hops between strips made for the Porter.
Starting up by your tips I did not exceed any margins, even ITT staying below the first red mark/in the green belt.
Oil cooler way open (pushrod completely in). After every landing letting the ITT cool to <200 deg.

All good, but on the third take off attempt sudden engine failure. This without any crossing of margins and oil temp always at or below 80.
So I blew an engine after 2 flights of roughly 10nm, takeing off on the 3rd.

Reset engine, now testing duration, taking away the starting and adding more running.
Setting: engine reset in mvams, go to EGPB Sumburgh, fly to EGJB via EGNL for refuel. 2x 3 Hour flights.
After 1st flight, mvams bar is in the green, appr 10% off full, engine status good.
After 2nd flight, mvams bar is in the green, appr 20% off full, engine status good.
All flights done with rpm of prop at 1900 and rpm% of 90 for cruise settings, 9000ft alt.

This in all leads me to believe the engine is way too fragile. Starts (in hot weather) are real killers, apparently regardless of pilot easing the engine so as to not cross any maximum numbers. Any flights done of about 3 hours flighttime seem to detract 10% off the engine life.

This leads me to the conclusion that:
- engine suffers too much from starting stress, even when started within acceptable parameters;
- engine suffers unreasonably high from normal cruise operation;
- this combined leads to a catastrofic engine failure between 3 (short flights) and 10 (longer flights) flights, or very roughly 1-30 hours;

I will continue to fly a mix of flights with this awesome bird to see how many hours/flights I need to blow her again

Any feedback? I'd also love to hear from other pilot's experiences in this regard.

More observations from a weary bush pilot .

Some 5 hours flown now without resetting the engine, in different climates.
In cool Alaska, the engine status bar in mvams is barely going down. Apparently the mentioned status of ca 1% per flight hour is correct.
In hot Papua New Guinea, the engine status bar in mvams is racing down, easily 7-10% per flight hour. This even though engine is operated in margins and the oil temp is at 80 degrees with oil cooler full open.

This suggests that the engine is fragile on operating it over it's limits, for which the pilot can accomodate;
but also that the engine becomes more fragile on operating in hot climates without out of margin operations, so for which the pilot can not accomodate.