Attitude Mode during vertical takeoff and hover landing

[subroutine]

Hi

I've been flying the Apache for about 40 hours and can control it reasonably well although it does get a little  out of control at times when taking off and landing. I'm using a nxt gladiator evo with a curve of 10 on the cyclic and rudder - no curve on the collective. I currently have no pedals so having to use the twist on the joystick which isn't that great for control. I find it much easier to get light on the wheels then engage attitude mode to takeoff in tight spots. Same applies to a hover landing- I get to a stable hover - engage attitude hold and reduce collective to land. I use attitude hold to attack targets especially during unmasking/masking using the FCR but I think that's acceptable practice. I like to stick to realism so was wondering do pilots in a real Apache sometimes use the attitude hold during vertical takeoff or hover landing ?

 

Edited June 15, 2024 by subroutine

[bradmick]

Nope. The force trim is held interrupted until the aircraft has been stabilized at the desired attitude and altitude, then released. Once released the hold modes come on. This ensures the system has the maximum authority to keep the helicopter at the desired attitude and altitude.

 

This is the way.

Edited June 15, 2024 by bradmick

[subroutine]

Thank you for your help and explaining why it's done that way. I've just ordered a set of VKB-SIM T-RUDDER PEDALS so hopefully that will make it easier to control. Using a twist grip for the rudder makes it much more difficult to maintain fine adjustments on the cyclic, which seems to be  essential  in stopping the Apache getting out of control.

[bradmick]

Pedals are definitely the one peripheral I’ll always recommend for helicopter folk. Flying without pedals is a rough time.

 

I’ll add too that the SAS has a limited authority before it saturates (runs out of authority to do work to stabilize the aircraft). Total authority is 10% months n all axes except for forward pitch, which has 20%. The 20% has been attributed to recoil damping during gun firing and compensating for transverse flow effect (difference in lift between fore/aft sections of the rotor disc). There was a third reason, but I can’t remember it at the moment. I’m. Partial to the transverse flow reason myself since it’s ever present during forward flight.

[subroutine]

Thanks for your reply. I have my pedals now and it is a lot easier to fly. I'm curious what setting you use for trim and curves ? I'm finding an 8 curve on cyclic and rudder, none on collective. Trim setting, instant on cyclic, been switch from central and No spring/FFB on rudder even though my pedals have a light spring. Can't make my mind up on the rudder trim options because all have their down sides.

 

[jaylw314]

11 hours ago, subroutine said:

Thanks for your reply. I have my pedals now and it is a lot easier to fly. I'm curious what setting you use for trim and curves ? I'm finding an 8 curve on cyclic and rudder, none on collective. Trim setting, instant on cyclic, been switch from central and No spring/FFB on rudder even though my pedals have a light spring. Can't make my mind up on the rudder trim options because all have their down sides.

 

For rudder and cyclic, I prefer leaving all the springs off and using clutches/damper if available, then using the "No Springs" trim setting.  It means you don't need to do anything when resetting trim, you just leave the controls where they are.  With the other options you have to think about recentering that control, which is impossible if there are no springs.  If you do it this way, you want no curve, since any position could be the "center" of your controls.

I suspect this is harder with a small throw in the relevant control, so it may be a preference thing

[subroutine]

I think I'll try removing the springs from my joystick and tighten down the clutches slightly. I can then  select No spring/FFB for the cyclic.

[JetCat]

On 6/15/2024 at 3:17 PM, subroutine said:

I like to stick to realism so was wondering do pilots in a real Apache sometimes use the attitude hold during vertical takeoff or hover landing ?

 

On 6/16/2024 at 1:22 AM, bradmick said:

Nope. The force trim is held interrupted until the aircraft has been stabilized at the desired attitude and altitude, then released. Once released the hold modes come on.

So I am doing it wrong almost all the time? I am too clumsy and not experience enough flying sim helicopters to hold it stable while hoovering, especially on windy days, and therefore I almost always land with attitude hold mode + manual pitch control only with minus 400 feet per minute setting. (Or a roll-out landing with at least 30-40 knots forward speed like it was a Cessna.)

 

[mcfleck]

Pedals are definitely the one peripheral I’ll always recommend for helicopter folk. Flying without pedals is a rough time.
 
I’ll add too that the SAS has a limited authority before it saturates (runs out of authority to do work to stabilize the aircraft). Total authority is 10% months n all axes except for forward pitch, which has 20%. The 20% has been attributed to recoil damping during gun firing and compensating for transverse flow effect (difference in lift between fore/aft sections of the rotor disc). There was a third reason, but I can’t remember it at the moment. I’m. Partial to the transverse flow reason myself since it’s ever present during forward flight.

You might have mixed transverse flow with dissymmetry of lift (advancing blade experiencing more lift than retreating blade, gyroscopic effect results in the force manifesting with a phase shift of 90°, front part of the disk up, rear down, aka "blowback")
The transverse flow would push you to the right roughly during ETL speed when the front part of the rotor disk is exposed to "fresh" horizontal flow, while the rear part has not yet outrun the "dirty" air with the downward component. More lift in the front, manifesting 90° later on the left side of the rotor disk => right push
(Not as pronounced in DCS in my opinion)

Is the 20% pitch authority additionally related to the NOE mode? You might require more pitch authority when the horizontal stabilator kicks in and starts pushing the nose down? Just guessing at this point.
Thanks for the information so far.

[JetCat]

Attitude hold mode maybe has too low tail rotor authority. I have tried a take-off with attitude hold mode on, it can be switched on while parking on the ground, and it works great. But has two problems so finding the sweet-spot takes a bit of practice.

When pulling the collective stick too fast the helicopter starts to spin for some time, and because attitude hold has very low tail rotor authority so it will turn 180° or even more before stabilizing itself.

When pulling the collective stick too slow the helicopter will tilt over.

 

[bradmick]

Attitude hold has no influence on heading. Heading hold does though, and heading hold is always on once you’re off the “weight on wheels” (squat) switch.

 

Also, the main rotor torque is massively exaggerated in the dcs Apache, this is why it requires so much more pedal than seems reasonable and the heading hold struggles so much.

Edited July 5, 2024 by bradmick

[Blackhawk163]

On 7/5/2024 at 8:00 AM, bradmick said:

Attitude hold has no influence on heading. Heading hold does though, and heading hold is always on once you’re off the “weight on wheels” (squat) switch.

 

Also, the main rotor torque is massively exaggerated in the dcs Apache, this is why it requires so much more pedal than seems reasonable and the heading hold struggles so much.

 

Is it ever! Is this a scheduled fix? Or is it a more of a kinda live with it type of thing? My quick stops suffer, but I guess if I want, I could always go back to the Black Hawk and reprise my troop hauling days