Questions regarding engine and rotor RPM during startup and idle lamp (RLT)

[gulredrel]

Hello,

first I want to they thankyou for updating the Gazelle with the new FM. It "feels" much more natural now from what I would expect an helicopter would react.

Also performance being much more affected by weight is great.

There are some things I want to ask regarding behavior during startup of the engine.

1. rotor and engine rpm

When the engine is running, I engage the throttle just a bit so that the rotor starts spinning and wait until the two needles sync. From than on, advancing the throttle slowly to max. I see that the rotor RPM needle always stays behind and never syncs with the engine rpm needle. This eventually happens when reaching max. rpm. Is this normal?

2. idle light (RLT)

The yellow engine idle light (RLT) is described as "This yellow lamp will light up when turbine idle is not reached." I would expect the light to extinguish, once throttle is at max and rotor RPM needle is synced. Currently, the light extinguishes when pulling collective > 35% (or something like this).

Please also check the video below:

Thanks

Jens

[Rudel_chw]

On 6/11/2023 at 2:25 PM, gulredrel said:

There are some things I want to ask regarding behavior during startup of the engine.

1. rotor and engine rpm

When the engine is running, I engage the throttle just a bit so that the rotor starts spinning and wait until the two needles sync. From than on, advancing the throttle slowly to max. I see that the rotor RPM needle always stays behind and never syncs with the engine rpm needle. This eventually happens when reaching max. rpm. Is this normal?

 

Hi,

I've noticed the same, and it does not seem normal to me, and older Gazelle videos showed the needles synchronized a bit after the main rotor began to rotate. 

Also, on the new Gazelle the main rotor begins to rotate with the slightest advance of the Fuel Flow control lever, say just a tap of the Page Down key is enough to start the rotor, while on the older aircraft the rotor acceleration was much more gradual and required much more advance on the Fuel Flow lever.

 

On 6/11/2023 at 2:25 PM, gulredrel said:

2. idle light (RLT)

The yellow engine idle light (RLT) is described as "This yellow lamp will light up when turbine idle is not reached." I would expect the light to extinguish, once throttle is at max and rotor RPM needle is synced. Currently, the light extinguishes when pulling collective > 35% (or something like this).

 

The Manual of the real SA-341G (which is not the exact same aircraft as the Gazelle from Polychop, being a civilian version of the helo), says that the Gazelle's engine actually has two different systems for getting fuel onto the engine: one for normal operation, and one that only works during the engine start sequence. 

The latter system includes a micropump to atomize the fuel going onto the ignitors and an ignition coil. The RLT lights when this system begins to operate and should go off at the end of the start sequence, once the normal fuel system begins operation.

Would love to hear from Polychop about this, since the Manual is not really detailed enough.

Best regards,

 

Eduardo

Edited June 16, 2023 by Rudel_chw

[gulredrel]

9 minutes ago, Rudel_chw said:

"new Gazelle the main rotor begins to rotate with the slightest advance of the Fuel Flow control lever, say just a tap of the Page Down key is enough to start the rotor, while on the older aircraft the rotor acceleration was much more gradual and required much more advance on the Fuel Flow lever.

Exactly my thoughts. Would also think, the clutch engagement would occur with a bit higher than this idle rpm and than the needles should sync and you need to stabilize and only than one should advance throttle further.

Thanks, also would love to hear from PC more about this. Maybe it needs a bit more tuning.

[gulredrel]

Being light and flying with low power settings, the idle lamp illuminates...

 

[Rudel_chw]

3 hours ago, gulredrel said:

the idle lamp illuminates...

maybe you moved the fuel flow lever back a bit? It should light if the turbine rpm are reduced.

[gulredrel]

I checked this, as I also thought I may had accidentally moved the slider an my T.16000 base, but it was all the way up. So for me it currently looks as if the lamp is only dependent on amount of torque. As soon as I pulled on the collective, lamp went out.

[Kinkkujuustovoileipä]

Engine/governor needs some tuning, I suspect NG is too low when power requirement is low.

[Shadok]

On 6/11/2023 at 8:25 PM, gulredrel said:

1. rotor and engine rpm

When the engine is running, I engage the throttle just a bit so that the rotor starts spinning and wait until the two needles sync. From than on, advancing the throttle slowly to max. I see that the rotor RPM needle always stays behind and never syncs with the engine rpm needle. This eventually happens when reaching max. rpm. Is this normal?

 

For now, advancing the throttle slowly or very quickly don't break the engine.

[grim_reaper68]

Since the latest update, you still need to let the starter on, which for me is  not normal, but maybe i'm wrong. So the turbine breakdown also disappear.  

[MAXsenna]

2 hours ago, grim_reaper68 said:

Since the latest update, you still need to let the starter on, which for me is  not normal, but maybe i'm wrong. So the turbine breakdown also disappear.  

Apologies, but I don't understand the part about the starter. Isn't this normal? 

I flip battery and generators. 

Fuel pump, clock, wait 20 seconds

Starter, wait for lights

Rotor brake, then fuel lever slowly to full stop, then switch on autopilot, gyros etc. 

That's it for me. Exactly like the cold and dark tutorial. 

Cheers! 

[grim_reaper68]

If I remember correctly, once the turbine at nominal power, you could shut off the starter. But maybe i'm wrong. 

[MAXsenna]

On 7/4/2023 at 12:17 AM, grim_reaper68 said:

If I remember correctly, once the turbine at nominal power, you could shut off the starter. But maybe i'm wrong. 

You could be right, I have no clue. Never read the manual, and it's not in the training mission. Gotta test this. 

Cheers! 

[MAXsenna]

On 6/19/2023 at 9:02 AM, gulredrel said:

I checked this, as I also thought I may had accidentally moved the slider an my T.16000 base, but it was all the way up. So for me it currently looks as if the lamp is only dependent on amount of torque. As soon as I pulled on the collective, lamp went out.

I need to have a small deadzone for the fuel lever to be sure it's all the way forward. You can sort of listen to it before you start. 

Cheers! 

[grim_reaper68]

I saw 2 video of real startup, once from a SA341 and one of an SA342, in the first they cut off the starter, in the second not.

 

[gulredrel]

Switching off the starter didn't work in our DCS Gazelle even with the old flight and engine model. As it represents the 342 with the different engine than the 341, so I guess, this is correct.

PC said on their discord, the above mentioned behavior is known and will be fixed.