w.i.p Autorotational behavior of the DCS Apache

[iFoxRomeo]

Short video to demonstrate the current AR behavior of the DCS (2.7.16.28157) Apache

• Airstart 70% fuel
• no external loads
• 100% gun ammo
• 66% MTOW / 6900kg AUW
• FMC disengaged

ENG page on right display to monitor the STAB POS

UGOU XXXXXXZ 15015KT 9999 CAVOK 15/01 Q1013 NOSIG

1. Autorotational descend
2. AR 180 left, EPL remain in fly position
3. AR 180 left, EPL idle after entering AR
4. AR 180 right, EPL remain in fly position
5. AR 180 right, EPL idle after entering AR

Bonus:

1. Full AR 360 left, EPL idle after entering
2. Full AR 360 right, EPL idle after entering AR, FMC ENGAGED but I didn't use FTR

 

The track and the mission is attached, so you can see and try for yourself.

I didn't autorotate for a while, so I wanted to do a few warmups in the Huey first, but had to setup the controls in this flight, so the behavior might seem strange, while I fly the Huey(entering control setup and adjustment of axis is not recorded in the .trk file).

 

Required control response during power on and power off AR should be similar and full control of the helicopter should remain.

 

 

video.trk AR Training_150-10.miz

[Scaley]

Nice video. The incorrect behaviour in autorotation was reported about a week after the module launched and as far as I know the most up to date reply from ED is "work in progress". Right now all you can do is not autorotate.

[Swift.]

As Scaley said. My best guess is theres some odd behaviour where the sprag clutches don't disengage. Which would explain why a sharp reduction in the power levers is met by an equally sharp reduction in the rotor RPM, and why power on collective full down autorotation has both the engines and the rotor matching at about 103%.

Additionally, 'sticky' sprag clutches would explain why the single engine performance is much worse than charts indicate, as an example if your dual engine torque for a regime of flight is 40% then you'd expect the single engine torque to be 80%, but what we see is more like 110% for the single engine(in this example). Which would match with the remaining engine having to drive both the rotor and the dead engine.

[iFoxRomeo]

22 hours ago, Scaley said:

Nice video. The incorrect behaviour in autorotation was reported about a week after the module launched and as far as I know the most up to date reply from ED is "work in progress".

Thanks.

I hoped it was already (internally)reported. My intention was also to document the current state and to see how it improves over time.

22 hours ago, Scaley said:

Right now all you can do is not autorotate.

But I love to autorotate

 

 

20 hours ago, Swift. said:

As Scaley said. My best guess is theres some odd behaviour where the sprag clutches don't disengage. Which would explain why a sharp reduction in the power levers is met by an equally sharp reduction in the rotor RPM, and why power on collective full down autorotation has both the engines and the rotor matching at about 103%.

Additionally, 'sticky' sprag clutches would explain why the single engine performance is much worse than charts indicate, as an example if your dual engine torque for a regime of flight is 40% then you'd expect the single engine torque to be 80%, but what we see is more like 110% for the single engine(in this example). Which would match with the remaining engine having to drive both the rotor and the dead engine.

Yes, it "feels" like that. 

[Rav3nX]

I haven't done many autos in the Ah-64; mostly because there's pre-trained lizard brain that just panics when the cyclic position weirdness happens; but obviously the flight models autorotation stuff is miles off right now; The whole aft cyclic thing......when you dump the collective in a helicopter to enter autorotation; the cyclic doesn't....move? you need to obviously adjust where your cyclic is but there's none of this riding the back stop rubbish or substantial uncommand roll; it just flat out doesn't happen, the cyclic just does what cyclic's normally do. 

Not sure how best to explain it.

I have also noticed the cyclic becomes very 'spongey' at low collective positions, this again doesn't happen. The blades pitch changes with the cyclic the same amount regardless of the collective position, its as sensitive at high power settings as it is at very low collective pitch angles. I have never noticed a difference in cyclic 'feel' in all the many autos I have done in my life. And defiantly no being in the back left corner of the cyclic travel turning right and pitching down like that; I'd probably jump out the door if I ever felt that  That's nightmare fuel. 

[BIGNEWY]

On 8/23/2022 at 8:39 AM, iFoxRomeo said:

Short video to demonstrate the current AR behavior of the DCS (2.7.16.28157) Apache

• Airstart 70% fuel
• no external loads
• 100% gun ammo
• 66% MTOW / 6900kg AUW
• FMC disengaged

ENG page on right display to monitor the STAB POS

UGOU XXXXXXZ 15015KT 9999 CAVOK 15/01 Q1013 NOSIG

1. Autorotational descend
2. AR 180 left, EPL remain in fly position
3. AR 180 left, EPL idle after entering AR
4. AR 180 right, EPL remain in fly position
5. AR 180 right, EPL idle after entering AR

Bonus:

1. Full AR 360 left, EPL idle after entering
2. Full AR 360 right, EPL idle after entering AR, FMC ENGAGED but I didn't use FTR

 

The track and the mission is attached, so you can see and try for yourself.

I didn't autorotate for a while, so I wanted to do a few warmups in the Huey first, but had to setup the controls in this flight, so the behavior might seem strange, while I fly the Huey(entering control setup and adjustment of axis is not recorded in the .trk file).

 

Required control response during power on and power off AR should be similar and full control of the helicopter should remain.

 

 

video.trk 4.09 MB · 0 downloads AR Training_150-10.miz 16.33 kB · 0 downloads

Hi, 

autorotation needs to be tweaked, and yaw / slip is known and will also be tweaked so consider the flight model w.i.p during early access. 

I will share your post with the team. 

thanks

[Rav3nX]

47 minutes ago, BIGNEWY said:

Hi, 

autorotation needs to be tweaked, and yaw / slip is known and will also be tweaked so consider the flight model w.i.p during early access. 

I will share your post with the team. 

thanks

We (I anyway) understand it's currently w.i.p; and it's excellent so far, the feedback is given as assistance; not criticism. You guys have done a damb fine job to get here.

[FalcoGer]

On 8/23/2022 at 12:32 PM, Swift. said:

As Scaley said. My best guess is theres some odd behaviour where the sprag clutches don't disengage. Which would explain why a sharp reduction in the power levers is met by an equally sharp reduction in the rotor RPM, and why power on collective full down autorotation has both the engines and the rotor matching at about 103%.

Additionally, 'sticky' sprag clutches would explain why the single engine performance is much worse than charts indicate, as an example if your dual engine torque for a regime of flight is 40% then you'd expect the single engine torque to be 80%, but what we see is more like 110% for the single engine(in this example). Which would match with the remaining engine having to drive both the rotor and the dead engine.

Might that also explain engine start troubles?

[admiki]

If you are refering to #2 engine not starting, if anything, that should make it easier for engine to start.

Edited March 4, 2023 by admiki