A couple simple questions

[cdlab1]

I'm getting acquainted with the PC-6 and think you've done a great job with it. I do have a couple questions that should have simple answers.

First, I cannot find any way to do the annunciator test before engine start. I see the panel, but no button to press.
Second, I'm not familiar with this type of engine, and other than your checklist I can't figure out when prop full forward is desired, and same with high idle. Should those be at full forward only on takeoff and landing, with low otherwise the preferred setting?

Thanks for your help.

[Taguilo]

Hi,

Annunciators test switch:

AnnTest.jpg (60.84 KiB) Viewed 3961 times

AFAIK this aricraft is generally flown with Prop Lever in full forward at it seems that position yields the best performance.
Anyway, there is no problem to fly with lower than max Prop RPM.
High idle can be used during taxi, or when recharging battery after an engine start to reduce ITT temp (same as in hot days).

Tomas

[cdlab1]

Thank you for the quick response, I appreciate it.

[thefrog]

I've blown up the engine more than once by running at reduced RPM (unless it was due to something else!)

[Richard Portier]

Hi,


AFAIK this aricraft is generally flown with Prop Lever in full forward at it seems that position yields the best performance.
Anyway, there is no problem to fly with lower than max Prop RPM.
High idle can be used during taxi, or when recharging battery after an engine start to reduce ITT temp (same as in hot days).

Tomas

Hi Tomas,
I would like to bounce back on your sentence.... I don't know if this is true in reality, but here's what I found in this excellent simulation.

If I fly with Prop Lever in full forward 2000rpm, sooner or later (most often sooner) I have a flame out while all the other parameters are ok (torque, oil temperature, turbine temperature and so on...).

At this moment, the only way for me to avoid these flame out is to reduce the prop rising to 1900rpm just after takeoff while keeping of course the other parameters within the indicated limits (torque, oil temperature, turbine temperature and so on...).

That seems to contradict your sentence, it doesn't mean that I'm right of course, but what about the reality? I would like to understand and see if maybe the problem lies on my side...

Thank you and Regards,
Richard

[Taguilo]

Hi,

I've blown up the engine more than once by running at reduced RPM (unless it was due to something else!)

It was indeed something else. When reducing prop RPM you must take care not to overtorque the engine. First, you need to reduce power (torque) and then prop RPM.

If I fly with Prop Lever in full forward 2000rpm, sooner or later (most often sooner) I have a flame out while all the other parameters are ok (torque, oil temperature, turbine temperature and so on...).

Prop at full forward (2000 rpm) will not affect engine performance at all. Simply put, it is not contemplated in the code.
Your flame out issues must be elsewhere. I recommend to pay attention to flashing digital data on engine gauges, as that is the most evident signal of an exceeded limit.

Tomas

[Richard Portier]

Hi,

I've blown up the engine more than once by running at reduced RPM (unless it was due to something else!)

It was indeed something else. When reducing prop RPM you must take care not to overtorque the engine. First, you need to reduce power (torque) and then prop RPM.

If I fly with Prop Lever in full forward 2000rpm, sooner or later (most often sooner) I have a flame out while all the other parameters are ok (torque, oil temperature, turbine temperature and so on...).

Prop at full forward (2000 rpm) will not affect engine performance at all. Simply put, it is not contemplated in the code.
Your flame out issues must be elsewhere. I recommend to pay attention to flashing digital data on engine gauges, as that is the most evident signal of an exceeded limit.

Tomas

Okay, I'll give it a try. Thank you.
Richard

[cdlab1]

I also have been having a lot of flame outs, and I've determined it only happens if I run through the start-up procedure myself. If I use Ctrl-E, then it doesn't occur. I watch the digital readouts carefully to make sure I'm not over stressing the engine, and in each case it will flame out as I'm gathering speed for takeoff, or within the first minute once airborne. Since the instruments say I'm within normal operating range, then I don't believe this is a case of pilot error.

Also, the heading and course indicators are turned by the middle mouse wheel, but in the opposite direction of the norms. The PC-6 is mouse wheel back that moves the indicator to the right, when normally that would be left, and so on.

Otherwise, it's a great plane that I enjoy. It's a perfect fit for the Papua New Guinea area.

[Taguilo]

Hi,
I believe you have not reset the engine status, therefore it will keep failing until you do so through MVAMS. Please check the POH.

Besides, CTRL-E does NOT trigger P3D Autostart event; it runs a custom routine that follows checklist’s procedure.

Tomas

[cdlab1]

Tomas, thanks for your reply. I did check the MVAMS quite often, and since it said the engine state was good I didn't click restore. I did so today, but the flame outs continued. However, I do think I know what's causing them now. ME! With this plane, you need to follow the start-up procedures to the letter, or things will go awry very quickly. I'll get the hang of it.

EDIT: Just when I thought I had figured this out, I get another flame out on takeoff. I followed the start-up procedures exactly as presented, and still had a flame-out on takeoff. I'll take my share of the blame, but maybe the plane is a bit too sensitive in this area.

[Taguilo]

Hi,
Well, I just flew out of KDP, Kandep airfield, in Papua New Guinea. It is indeed an ~8000 ft airport.
Special cautions you need to take if you want to maintain your engine healthy.
First of all, pay attention to OAT. If values are high , say 25 C or higher, I'd recommend that you follow these procedures:

-Before engine start, ensure that Oil cooling is shut (knob full forward)
-Put prop lever in full forward (max rpm)
-Turn On Fuel Pump and Ignition
-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 FEATHER the PROP on the ground, doing that in hot weather at high altitudes will increase oil temperature beyond safe values and that will affect the engine's health.
-Do not start the engine just after a shut down ,when ITT is still hot. 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.
-At such high altitude and temperature, ITT is the limit you must look after, increase take off power up to 5-10 deg lower than red mark (723 C). Torque will be below 40 PSI for sure, so expect a longer take off run.

Hope all of this helps you for a safe flight.

Tomas

[cdlab1]

Tomas, thank you for the detailed do's and don'ts on engine management. Learning this engine is a lot more complex than others in my hangar, but it's a great plane to fly.

[Flyfox]

Hi,
Well, I just flew out of KDP, Kandep airfield, in Papua New Guinea. It is indeed an ~8000 ft airport.
Special cautions you need to take if you want to maintain your engine healthy.
First of all, pay attention to OAT. If values are high , say 25 C or higher, I'd recommend that you follow these procedures:

-Before engine start, ensure that Oil cooling is shut (knob full forward)
-Put prop lever in full forward (max rpm)

Hi Thomas

You recommend to put the prop lever in full forward position at high ambient temperatures. But this is in contradiction to what is recommended in the checklist in your user manual. Which one is correct?

Felix

[Taguilo]

You recommend to put the prop lever in full forward position at high ambient temperatures. But this is in contradiction to what is recommended in the checklist in your user manual. Which one is correct?

Actually both. At high altitudes OAT is a factor both for ITT and Oil temp. Maintaining the props out of feather helps keeping oil temp within limits.
You can start in feather as well, but then you have to move to full forward as soon as engine stabilizes.
Besides, if needed to stay parked with engine running in high OAT, just move CL to near High Idle position, about 65-68 % N1 (Gas Generator RPM), in order to decrease ITT temp (coolest ITT is obtained around those values).


Tomas