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Unable to understand why I get LOW ROTOR RPM and loss of lift with 103% power in IGE facing into wind.


DmitriKozlowsky
Go to solution Solved by TrevorMcNeill,

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Unable to understand why I get LOW ROTOR RPM and loss of lift with 103% power in IGE facing into wind. Wind is FROM 145 deg. at 5 knots.

So I establish , or try to, a control hover with nose pointed into the wind. This is the part where current AH-64D and my skill with it, or lack of it, is most chaotic. Strong oscillations in YAW and PITCH, less in ROLL. 1/2 times Bitchin Betty tells LOW ROTOR RPM, and helicopter settles, as if its in VRS. 

My control mission is Instant Action-Syria-ColdStart.

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8 hours ago, DmitriKozlowsky said:

Unable to understand why I get LOW ROTOR RPM and loss of lift with 103% power in IGE facing into wind. Wind is FROM 145 deg. at 5 knots.

So I establish , or try to, a control hover with nose pointed into the wind. This is the part where current AH-64D and my skill with it, or lack of it, is most chaotic. Strong oscillations in YAW and PITCH, less in ROLL. 1/2 times Bitchin Betty tells LOW ROTOR RPM, and helicopter settles, as if its in VRS. 

My control mission is Instant Action-Syria-ColdStart.

Can you give us track file?

My guess is that you are just overweight for conditions. Apache is not overpowered like Hind, so getting into hover from forward flight can be tricky.

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Its the Instant Action-Syria-ColdStart. mission. Loadout is as default. 50% fuel, 2 X rocket, and 2 X (2 Hellfire).

After start up with throttle at Flight . Taxi aircraft to 145 deg. heading. Met. is Wind FROM 145 and 5 knots, 29.92. Standard day. 

I find it odd that AH-64D is harder to hover and control in IGE, then it is in OGE. Once I enter into IGE slow flight to however, the oscillations in YAW, and ROLL increase dramatically. The slip indicator ball just dances from side to side.

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The only time I get LOW ROTOR RPM is when I add collective too fast.  You can run at 103% torque all day if you get there gradually.

If you add too much pitch to the blades all at once, it puts too much drag on the rotor system and the RPM drops.

Can you pick the helo up off the wheels right there on the runway and stay in IGE hover without issue?

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  • 2 weeks later...
  • Solution

Engines can only supply so much power/torque on certain days and 103% may be that max for the given day. Any more collective input past that will result in low rotor(rotor droop) as engines are not capable of keeping the rotors rpm within limits at the given rotor pitch. 

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