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KA50 Slow speed Yaw control?


IvanK

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Since it does not have a tail rotor how is Yaw controlled in slow speed stuff like the Hover ?

 

There is little airflow over the rudder , unless Rotor downwash deflected by the rear horizontal fins are suffcient.

 

How about some clever differential upper versus lower rotor speed type affair inducing controllable torque ?

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It is deceptively simple.

 

Since you have two main rotors, they both provide an equal amount of lift, and therefore produce an equal amount of torque (in a stable hover, for example).

 

To yaw one direction or the other, the flight controls increase the pitch of one set of blades, while simultaneously reducing the pitch of the other set. This results in having the same amount of total lift being generated, but now one set of blades generates more torque than the other set, resulting in a yaw effect in the opposite direction.

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Ok I understand thank you... another couple of questions though :)

 

In the Auto hover, I was under the impression the Ka50 would aim to auto centre the steering errors ... get the hover mark in the centre of the HUD and the HSI hover needles centred.

 

In my early attempts it doesn't seem to do this. The error just remains constant. Is there something I need to do to get the steering errors zeroed ?

 

One more question. In the Auto hover does the flight control system maintain altitude automatically or does auto hover simply refer to the 2D point in space with me manually controlling the height with collective ?

The Alt Hold light is illuminated implying to me some sort of auto height control.... though collective seems still to override any height control if it is working.

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If you want to zero the error without hovering to the 'original' position, just hit trim.

If you want to completely return to the original hover position, translate the chopper towards it while in auto-hover.

 

By default, Auto-Hover maintains radar altitude, HOWEVER the collective does have an influence and can override it. Hit 'f' to 'trim' the altitude you wish to maintain.

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One more :) Auto pilot usage.

 

If the FD button is down and you are not in ROUTE mode then am I correct to believe the AP is in damper mode in all axes ?

 

If I then select ROUTE mode (with FD button still down) the AP is effectively engaged and flying the KA50 ?

 

What I am getting at is how do I know whether the AP is in a damping or Stab Aug mode as to when it is in a "full authority" type mode ? Does the route Nav light on the overhead panel indicate a Full authority mode ?


Edited by IvanK
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It does, when it's ON the AP is in trajectory mode (enroute). Though I wouldn't call it full authority since the AP is given 20% of the servo actuators deflection range, which is quiet limited authority but yes- in this mode it controls all the servos to follow the route.

 

One slight clarification- in neutral the two rotors have equal torque, not lift. The difference is in the favor of the upper rotor which in certain regimes could have up to 20% more lift with the same torque. The yaw control has it's own name- differential pitch.


Edited by =RvE=Tito

"See, to me that's a stupid instrument. It tells what your angle of attack is. If you don't know you shouldn't be flying." - Chuck Yeager, from the back seat of F-15D at age 89.

=RvE=

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One more :) Auto pilot usage.

 

If the FD button is down and you are not in ROUTE mode then am I correct to believe the AP is in damper mode in all axes ?

 

If I then select ROUTE mode (with FD button still down) the AP is effectively engaged and flying the KA50 ?

 

I don't think so. With FD and Route, you still get stabilization but no autopilot. Turn FD off at that point and the autopilot will take over and follow the route. Get out of route mode and turn the FD off and you will get this confusing practically unflyable condition where the autopilots fights your every move all the way to the FARP (unless you kill the other blue lights of course).

 

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One slight clarification- in neutral the two rotors have equal torque, not lift. The difference is in the favor of the upper rotor which in certain regimes could have up to 20% more lift with the same torque. The yaw control has it's own name- differential pitch.

 

Thanks for the clarification! I need to get back to reading the FUNdamentals. ;)

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"Get out of route mode and turn the FD off and you will get this confusing practically unflyable condition where the autopilots fights your every move all the way to the FARP"

 

Now that confuses the heck out of me :) .... Doesnt "Route" mode simply say to the AP .. fly the planned sequence of waypoints... If FD are on then I get steering commands which I follow to fly the route with me polling the KA50. If the FDs are off then the autopilot flies the route for me.

 

If I want to just roar around the countryside on random headings sightseeing (no planned route say) what modes should I be in ? As I figure it I would NOT have route mode engaged, I can choose either to have ther FDs up or not. In this case the AP system is still providing damping in all axes ...is it not ? but I fly as desired. All the FDs would do (if selected) is provide a speed refrence with desired pitch marks ??


Edited by IvanK
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First up, remember that the Autopilot's Route mode is linked to the Nav computer NOT the ABRIS. The ABRIS and the Nav computer are like a married couple with problems. They share the same bed, but they don't talk or touch eachother.

 

Route mode tells the AP to follow the waypoints programmed into the Nav computer. Now these can be programmed in in the mission editor, or by you manually. It can however only hold six nav waypoints. A departure FARP/Airfield can be programmed under the Airfields button, and so can a different arrival airfield.

 

When you have Route mode on it will switch the waypoints as you pass them and thereby follow the Nav computer's waypoints as you'd expect in Route mode.

 

When you are flying with Flight Director on, the AP is off but the stability augmentation is still there so it makes flying the Shark that much easier.

 

When you are flying with Flight Director OFF and Route mode OFF the AP is trying to steer you to the current waypoint set in the Nav computer (most likely waypoint 1 if you are starting from the FARP or haven't touched anything else). To stop it from doing that you can either trim it... Or next to the HSI on the right is a little toggle switch that says something like Heading Auto/Manual.

 

If you flick that up to Manual it will no longer keep trying to point you at the waypoint. Now I can't remember if you need to put that back to Auto if you wanted the Turn to Target mode to work.

 

So to answer your question of "What mode"?

 

Well depends how you want to fly it, but I've always found Flight Director to be the most comfortable, but if you don't want the steering cues in the HUD then switch heading mode to Manual and you'll not have a Shark that wants to twist one way or another all day long.

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Get out of route mode and turn the FD off and you will get this confusing practically unflyable condition where the autopilots fights your every move all the way to the FARP (unless you kill the other blue lights of course).

 

I rarely fly FD on, almost always all channels on with no hover.

 

I've found it pretty simple to fly with FD off and all channels on, however I'm using force feedback joystick so trimming to wanted attitude that AP will hold for me is almost trivial: Just point to wanted bank&pitch, press trim and it stabilizes itself to that bank angle and pitch automatically. For height, i just keep F pressed down when I need level change, otherwise I trim my collective so that alt hold can hold my level.

 

Flying this way, you don't even need autohover in combat because it's pretty easy to put KA-50 to fly slowly forwards in constant speed and level while skanning targets in shkval.

 

Trimming the rudder is harder as it's not force feedback controlled, so pressing trim will offset the centerpoint and I need to do trim in small sections to prevent overtrimming.

 

Trimming is the key here too :)

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