Hi,

I was in a hover and noticed how FD and Non-FD was functioning. With FD on in a hover if I initiated a slight roll and trimmed, the roll would continue until the heli was on its side and drop like a rock. If while in a hover I initiated a small pitch up and trimmed, the heli would continue pitching up until the it was standing upright like a begging puppy and then drop.

I have read countless articles/threads (including the excellent one from Einsteien) on FD and auto pilot and never came across mention of this behavior. What is the purpose of maintaining a constant roll or pitch when it will eventually put the heli in an attitude sure to bring it down.

Concerning strafing a line of vehicles with cannons. I have been practicing this and I turn off DH/DT mode and have FD turned off. For the life of me I cannot keep the pipper on the line of vehicles. I might get one vehicle on a pass and then I start bobbing around like a drunken porpoise. I fly with a warthog and ch pedals. What is the technique that others use to straf in a straight line. When I try to make a quick turn I sometimes find that I have almost no rudder authority so I'll hold in the trimmer to regain it. For those who have strafing down how do you handle the trimmer. I can't imagine your trimming the entire run of the strafe.

Help!!!! I'm tired of being a drunken porpoise.


Thanks guys for any advice,

Tom

FD isn't maintaining anything. FD ON = AP OFF.



A track would be nice. If I need to strafe, I'll be trimmed for it well before the beginning of the strafe so all I have to do is drive forward, and the pipper walks over the column by itself. If you miss, you miss ... bug out or come back again, depending on your plans.

If you're trying to strafe while flying parallel to the column, realize that the AP will hold your attitude (pitch, heading) once you trim - so again, be trimmed out before you begin the strafe. You can make very small adjustments without ill effect, so make sure you're already aimed correctly before you begin. If you're not, just abandon the strafe.

Thanks GrayGhost for replying.

I will try to upload a track this evening of the behavior I mentioned. With FD on when I trimmed while rolling very slowly the roll would continue after centering the stick until the BS fell from the sky and the same would happen with a slow pitch change added. With FD on it seemed to maintain the RATE of the cyclic input after trimming and centering the stick.

When you mentioned FD on = auto pilot off, do you mean that with FD on and when trimming the AP will not try to maintain the newly trimmed attitude and vector?

Thanks.

Correct, you are simply setting the centre point for the cyclic when trimming with the FD on.

Nate

While a given stick position may keep the helo level in a hover at zero velocity, a different one will be required to maintain a different flight condition. Helos are by nature unstable in this way; the controls must constantly be adjusted and changed to maintain or change flight direction and velocity. Perfect example of this is the nose wanting to pitch up as you accelerate forward. This is caused by disymmetry of lift across the rotor disks, and countered by applying (and maintaining) more and more forward cyclic as airspeed increases.

If a missile blasts one wing off (it's happened to me before in DCS) you'll have to put in a large amount of lateral cyclic to keep the weight of the other wing from rolling you on your side.



The most stable flight condition is going to be forward flight, with the fuselage streamlined through the air. Slow speed hovering or flying sideways while strafing is gonna make you work even harder with those flight control inputs to maintain the pipper on target. Even if a pilot could keep the helo absolutely stable, as soon as you pull the trigger, the recoil from the gun is gonna drag the pipper right, much like if you were to fire an automatic rifle from your right shoulder. Even the helo's flight computer and hold modes can't dampen that.

As for losing your yaw authority, most likely you've trimmed the pedal input to one side, so when you try to apply it in the opposite direction you're effectively moving the pedals back to "center". You can either look down in the virtual cockpit to see where the cyclic and pedals are physically located to maintain reference, or you can enable a graphic that's displayed on the screen to show where the controls are. The command for this is in the Options menu, on the Controls tab, in the section called General ("Show controls indicator").

Ok, I think I understand it after flying BS last night. With FD off you move the stick and trim and the AP will maintain the current attitude when you trimmed, that I understood before. By turning on the FD when you move the stick and trim you are making a cyclic change that is just maintained after centering the joystick (in real life the stick would remain in the position when you trimmed). With FD on the attitude is not maintained, just the cyclic pitch is maintained and pressure released from the stick (IRL).

Example 1 FD off: In a hover initiate a slight roll (let's say 3 degrees of cyclic right) and then trim and center the joystick. The AP will attempt to hold the attitude the heli was in when you trimmed.


Example 2 FD on: In a hover initiate a slight roll (let's say 3 degrees of cyclic right) and then trim and center the joystick. The heli will continue to roll after centering the joystick because after trimming, the stick is still held in the cyclic position of 3 degrees right.

To sum it up:
FD off, the auto pilot maintains attitude at the point you trimmed
FD on no auto pilot is controlling and the cyclic input you held at the time of trimming remains and the stick in real life stays where you trimmed it.

This is how it behaves for me and now it makes sense.

My strafing improved somewhat last night...I can now get two in a convoy in a pass. I know, still awful. What throws me off is when the cannon fires it starts me bouncing.

Thanks for the replies,

Tom

Most gun and rocket engagements are against static, or at least single targets. Only strafe if it really makes sense to. A tighter group of rounds makes it more likely that you will destroy a vehicle for example.

Also, if you have the maneuver room and time, you will have your greatest accuracy by locking on to a target with the Shkval. This will keep the gun locked on target, even as the recoil moves the aircraft. And it will also keep the range calculations up to date for the rocket CCIP as well (I think).

Another useful method to use, especially with rockets, is place the AT-GS switch to GS (the switch between the HMS and Laser switches). There's a procedure in the flight manual (page 11-28 I believe) describing how to use this method to provide range calculations for fixed cannon and rocket engagements. It will definitely reduce the amount of rockets you waste trying to walk onto your target, assuming your firing one rocket pair at a time. It will also allow you to attack more than one target in a single pass more easily, compared to locking on to each target individually with the Shkval.

I came late to this party, but I don't have much to add: the folks above have nailed it. Well done!

The Flight Director removes all feedback control from the autopilot. All you're left with is control input stabilization.

The Flight Director does not affect the behavior of the Trimmer in that the Trimmer will still center the zero-force location of the stick. Your AAR above is a nice demonstration of that. Kudos on experimenting with the FD, by the way - really helps you understand the autopilot and Trimmer, doesn't it?

As for strafing, in my opinion, the 2A42 30mm cannon on the Ka-50 is poorly suited for strafing runs like you may have seen in WWII aircraft: the 2A42 just doesn't have the power factor to be effective for the short engagement time you'd have in a running strafe. You're much more likely to be killed by whatever you're shooting at before it kills you. If the target isn't a threat, there's no need to run in at it: slow down to a comfortable airspeed and kill it at your leisure. If it is a threat, ambush it with a pop-up attack or at the edge of its engagement envelope and translate instead of flying towards the dang thing: it's just going to shoot at you anyways!

Now the gun pods are a different story: strap on a pair (or quartet!) of UPK-23 gunpods and unleash the dogs of pain! Yowza!

Thanks guys for all of the replies.