Hover Mode trouble

[number3]

I'm at a loss for figuring out why when I go to hover (when I'm at a near manual hover) why the helo goes ballistic on me and does anything BUT remain in the spot it should be.

 

I've read the manual many times, founds a few posts about it and don't understand what I'm missing or doing wrong.

 

I created a mission only my k-50 (taking off from runway) and no waypoints. Proceed to take off, create some forward speed. Then proceed to slow down to a near hover, making sure I'm below 40km/h and neutralizing any yaw. I double check that the ROUTE - DESCENT switch is in the neutral position.

 

Then press the magical HOVER button, I can see the overhead panel "hover" light go off. Let go of the cyclic stick. My hud changes to show the spot where I initiated the hover and how much deviation has happening.

 

Now comes the entertaining part, where the k-50 proceeds to pitch up or down or bank left or right. The square on my hud is no longer in the center and the k-50 starts to go on like a raging bull till the point where a crash is unavoidable. Or in some cases I don't crash, I just end up moving completely away from the hover point in a direction that is perpendicular to the k-50.

 

I even tried resetting the trim before I initiate hover mode with no success.

 

So I'm at a loss and have no idea what is going on or what I have to do.

 

Anyone else having the same problem? Or any suggestions?

[slug88]

Post a track.

[opformaster]

Try initiating the hover when your speed is under 20 km/h. And is the ALt. hold light comming on as well? If not make sure to turn off the FD, it will override the Alt. Hold.

 

-op4

[AlphaOneSix]

Is this always happening just after you take off? Are your autopilot lights blinking? If so, it could be that your INU has not completed its initial startup routine. Try waiting another minute or two before taking off.

 

Also, you say that you are at a near hover, but that you wait until you are below 40kph. That's nowhere near a hover, you should be below 5kph.

Edited January 25, 2009 by AlphaOneSix

[Jack57]

Even in full AP mode you will need to have control inputs until it is properly trimmed - you can't just let go of the cyclic. Even then, if you have centering springs in your joystick you will probably have to hold the cyclic in position depending on the current weight and balance of the helo and wind conditions. This is why I take the springs out my joystick - once you become accustomed to it you will never go back (this for helo flight). It is far more realistic if you don't have FF.

Also, you say the hover light goes out? Sounds like you are already in auto hover and are turning it off.

 

Hope that helps,

Jack :)

[number3]

Posting a track

 

Yes the ALT-HOLD is coming on and the FD is off. In this tack I didn't set trim what so ever.

 

And you'll see I tried to the hover mode multiple times with pretty much the same result.

[number3]

Is this always happening just after you take off? Are your autopilot lights blinking? If so, it could be that your INU has not completed its initial startup routine. Try waiting another minute or two before taking off.

 

Also, you say that you are at a near hover, but that you wait until you are below 40kph. That's nowhere near a hover, you should be below 5kph.

 

I meant, that when I initiate HOVER mode I'm always below 40km/h. I posted a track where I've gotten close to the speed you recommended before initiating HOVER mode.

 

Jack57: are you saying that I should when I'm manually hovering, that I should trim till the point where I can center my cyclic and then initiate hover mode?

[number3]

2nd track

 

Jack57: I'm attaching a second track where I use trim when I'm at a near hover to the point where my cyclic stick is centered. Initiate HOVER mode and the results are much better.

 

Got out of HOVER mode, created some forward speed and repeated the same steps when I was at a near hover. This time you'll see that the square on my hud off to the left. Now should HOVER mode be doing corrections so that the square on my hud is centered?

Do you have FF joystick and does this mission start from the air or the ground?

[number3]

Do you have FF joystick and does this mission start from the air or the ground?

 

I do not have a FF joystick. I've got an saitek x45. The mission starts from the ground with the k-50 systems powered up.

[GGTharos]

I'm going to make a guess here ...

 

Then proceed to slow down to a near hover, making sure I'm below 40km/h and neutralizing any yaw. I double check that the ROUTE - DESCENT switch is in the neutral position.

 

Too fast. Don't accept 40, bring it down to 10 (edit: or better yet, as AlphaOneSix said, 5)

 

Then press the magical HOVER button, I can see the overhead panel "hover" light go off. Let go of the cyclic stick.

And here's my guess .... that's your mistake. If you cannot stay in a near-hover without letting go the stick BEFORE you autohover, you may well have more cyclic input than the autopilot servos can handle ;)

 

I even tried resetting the trim before I initiate hover mode with no success.

Definitely a huge mistake.

 

So I'm at a loss and have no idea what is going on or what I have to do.

Trim it out for hover. That's all.

[Zembla]

I'm probably gonna repeat a lot of the things that have been said before, but to give you a better understanding, the autopilot in the Ka-50 will only compensate for 25% or so of your input. So, in other words, to remain stable, your controls have to be within a 25% boundary of being stable.

 

As you said, and as many have said, you need to trim the bird to a hover before initiating autohover. Well, in fact you don't necessarily have to do that probably if you're going to keep your hand on the stick, but the purpose of the autohover is there to make sure you don't need to have your hand on the stick.

 

So, as has been said, instead of slowing down, pushing the autohover and then releasing the cyclic, how about, slowing down, stabilising, pushing the trim button, releashing the cyclic, engaging the autohover.

 

-Z

[jakeman]

Jack57: I'm attaching a second track where I use trim when I'm at a near hover to the point where my cyclic stick is centered. Initiate HOVER mode and the results are much better.

 

Got out of HOVER mode, created some forward speed and repeated the same steps when I was at a near hover. This time you'll see that the square on my hud off to the left. Now should HOVER mode be doing corrections so that the square on my hud is centered?

 

From the tack you posted I can see that you have a set of vihkrs at just one of the wings. In that case the auto hover will make corrections, and the square will not center out.

[number3]

I'm probably gonna repeat a lot of the things that have been said before, but to give you a better understanding, the autopilot in the Ka-50 will only compensate for 25% or so of your input. So, in other words, to remain stable, your controls have to be within a 25% boundary of being stable.

 

As you said, and as many have said, you need to trim the bird to a hover before initiating autohover. Well, in fact you don't necessarily have to do that probably if you're going to keep your hand on the stick, but the purpose of the autohover is there to make sure you don't need to have your hand on the stick.

 

So, as has been said, instead of slowing down, pushing the autohover and then releasing the cyclic, how about, slowing down, stabilising, pushing the trim button, releashing the cyclic, engaging the autohover.

 

-Z

 

Thanks guys. So my problem was that I was not trimming so that my cyclic stick could be centered on it's own before setting HOVER mode.

[Maverick-GER-]

Also everytime your autohover goes crazy check if your autopilot channels are engaged, a few times already it happened to me that engaging my autohover it somehow disabled my heading, pitch and bank hold and only had alt mode on....it even did that repeatable 3 or 4 times before it would finally leave my AP channels on when engaging Autohover

[ruprecht]

I also make a point of cycling my AP switches before I take off. I don't know why, but it seems to make a difference to the autohover. The process I use is:

 

(before takeoff)

- cycle all AP switches

 

(when hovering)

- check route mode off

- manually hover and trim

- engage autohover

- check overhead hover lamp on

- check AP lights, ensure all on

- when all remaining lateral movement stops, trim

[Sunjah]

...Are your autopilot lights blinking? If so, it could be that your INU has not completed its initial startup routine. Try waiting another minute or two before taking off...

 

Is that why that happens? THANK YOU!!! As I started to read this thread, I thought, "Wow, I have to find out why those Auto-Pilot lights start blinking at takeoff!"

 

For the original poster, I've found that it makes a world of difference to "re-trim" my helicopter right before take off. I read it was 7*, but I kind of feel like about 1/5-to-1/4 of the way is good. While on ground, after "Watch EKRAN" message, I press trim, push forward as stated (just so the helicopter does not roll forward yet), let trim go. This sets you up for a nice, clean takeoff.

 

I usually "hover" take off, but if you put enough forward while doing the "re-trim," you will also have forward flight as you takeoff.

 

That, and now knowing the reason for the blinking AP lights (sometimes they work perfectly, sometimes they blink and don't work), make for a good take off.

[einar-st]

Also everytime your autohover goes crazy check if your autopilot channels are engaged, a few times already it happened to me that engaging my autohover it somehow disabled my heading, pitch and bank hold and only had alt mode on....it even did that repeatable 3 or 4 times before it would finally leave my AP channels on when engaging Autohover

 

As mentioned this is probably because the INU is not ready. (I knew something was not ready, but before AlphaSix wrote that it was the INU, I did not know that was it)

 

The way I know it's ready is the directional line that appears on the HUD at speeds below 50kph. If it's not there, I know I'm not able to autohover. Does anyone know of another way to see if it's up and running?

[hawkbug]

I use to experience much the same thing when I hit the auto hover button after a manual startup. Come to find out I forgot to move my throttle from low to auto setting, so the INU would constantly cycle but never fully engage.

[connos]

Also everytime your autohover goes crazy check if your autopilot channels are engaged, a few times already it happened to me that engaging my autohover it somehow disabled my heading, pitch and bank hold and only had alt mode on....it even did that repeatable 3 or 4 times before it would finally leave my AP channels on when engaging Autohover

 

I had that also. The heading, pitch bank and hold channels start flashing and then they get disabled and then the heli goes crazy? Is there a reason that this is happening?

[AlphaOneSix]

I had that also. The heading, pitch bank and hold channels start flashing and then they get disabled and then the heli goes crazy? Is there a reason that this is happening?

 

Your INU has not finished its initialization procedure. Sit on the ground for another minute or two before taking off. There is no indication when it's done, but it takes about three minutes from the time you turn on the INU.

[ZaltysZ]

Your INU has not finished its initialization procedure. Sit on the ground for another minute or two before taking off. There is no indication when it's done, but it takes about three minutes from the time you turn on the INU.

 

Also, INU can get screwed in mid flight after received damage, power outage or crazy maneuvers. Mostly it comes back to normal after some time.

[MTFDarkEagle]

You can tell if your INU is up and running again by the speed -o- meter on your HUD, on the top left. (its +(number) in km/h if you didnt know ;) )

[miguez]

You can tell if your INU is up and running again by the speed -o- meter on your HUD, on the top left. (its +(number) in km/h if you didnt know ;) )

 

Hi MTFDarkEagle,

 

Correct me if I am wrong, but that number (the ground speed, on the top left of the HUD) will only show up once you take off, and after a little while, since the doppler has to realize you're moving.

 

If you turn the helo on and stay on the ground, it will never show, even though the INU has finished alignment.

 

At least that's my understanding.

[MTFDarkEagle]

Hi MTFDarkEagle,

 

Correct me if I am wrong, but that number (the ground speed, on the top left of the HUD) will only show up once you take off, and after a little while, since the doppler has to realize you're moving.

 

If you turn the helo on and stay on the ground, it will never show, even though the INU has finished alignment.

 

At least that's my understanding.

 

well, true, but it "connects" to eachother. If you cant see the speed on the HUD, you cant hover. It will take time before it shows up on the HUD, if it is, you can hover :)