autohover and change heading??

[wolf_288]

Hi

when I set head hold off and have autohover on begin the chopper rotate in Clockwise direction why???I use it to change heading,it´s possible to slow down this rotation??

[159th_Viper]

Weathercocking?

 

Rudder Trim?

 

2 possible explanations.......Post a Track for a detailed Obduction.

[sinelnic]

Totally OT but I´d like to warn the owner of the LeadingEDGE Training shop that there´s a certain Tim Langdell lurking around all things called "EDGE", and might very well annoy you should you get any commercial success. Google is your friend!

[EtherealN]

No worry sinelnic, since the name Leading Edge has a clear rationale. (Leading Edge of an aerofoil.)

 

A question to Wolf - when you say "head hold off", do you mean the yaw damping channel? Try to see what's happening if you have the yaw channel active, since it may well be that disengaging that channel causes the autopilot to not have any authority at all over yaw which might cause the behaviour you are describing. I'll see if I can get that tested during the day.

[the_soupdragon]

How the heck can you trademark a word like Edge and then stop people using it? If it's true, How rediculous is that.

 

I think I'll go trademark the word "the" and "The"

 

BTW that guy is a total douchebag and needs to get a life.

 

SD

[159th_Viper]

How the heck can you trademark a word like Edge and then stop people using it?

 

You can always try.......Thing is, all Mr Clever will likely obtain in this instance would be a Punative Costs Order.

[wolf_288]

Hi

when I am in autohover position and try to turn heading with the rudder (+trim)I got a jump and is impossible to do it stable,when I release the Yaw (heading) autopilot channel I have good stable turn I want do this with the rudder to but how???(trim dont work here)

[EtherealN]

Could you attach a trk file showing this behaviour?

[26-J39]

Hi

when I am in autohover position and try to turn heading with the rudder (+trim)I got a jump and is impossible to do it stable,when I release the Yaw (heading) autopilot channel I have good stable turn I want do this with the rudder to but how???(trim dont work here)

 

Trim works regardless of AP's... Trimming without heading AP 'feels' like trim don't work cauz you don't have the 20% authority of the AP helping you.. I personally do prefer to turn off the heading AP when i need to yaw quickly when in hover, you just need to be more vigilant when trimming..

[26-J39]

Totally OT but I´d like to warn the owner of the LeadingEDGE Training shop that there´s a certain Tim Langdell lurking around all things called "EDGE", and might very well annoy you should you get any commercial success. Google is your friend!

 

:D This guy? http://www.tigsource.com/pages/edge-games/

 

This is a compilation of information about Tim Langdell, the owner of Edge Games, who I believe has abused the law and employed underhanded business tactics for 30 years for his own personal gain and at the expense of honest and hard-working developers.

 

Keep an eye on you're leading edges guys.. :P

[wolf_288]

Hi

it´s possible edit a trk file????

[159th_Viper]

Hi

it´s possible edit a trk file????

 

Views/Speed, yes. Actual Playback, no. All one can do is take control at any point through the Playback of the Track.

[wolf_288]

Hi

but when you turn off the heading AP you have the automatically turn to the right (ratation Clockwise)??

[EtherealN]

Which is the behaviour that is making me curious and interested in seeing a trk file of this behaviour. No need to edit a trk for it - just get airborne and perform the maneuvers as described and then save the trk file for upload. Without seeing it it's difficult to decide on an explanation for the behaviour.

[159th_Viper]

Hi

but when you turn off the heading AP you have the automatically turn to the right (ratation Clockwise)??

 

No.

 

We've now come a full Circle.......Post a Track as requested in the first Reply Post :)

[EtherealN]

Also, wolf_288, if it would be easier for you to get assistance in swedish I do speak that language. Feel free to PM me in that case.

[wolf_288]

Hi

I have a video her

[EtherealN]

Youtube video is nice, but the best would be a trk file since then I can view it as run by the simulator and also take control of it (and thereby ensure that when I look it over I have the exact same cockpit configuration). It also allows me to see the input commands received by the simulator to see if you have a controller issue - youtube video does not allow this.

 

Trk files are recorded automatically and can be saved after the flight via the "Save Track" button on the results screen. You can then find the trk file at C:\Games\BlackShark\Missions\Tracks\ (or equivalent install path on your machine) and upload it here through the paperclip icon (attachements manager) in the reply interface.

 

Anyways, I shall see if I can manage to replicate that.

Edited December 16, 2009 by EtherealN

[EtherealN]

From my own testing, the initial rotation when disengaging the yaw channel is easy to explain - you are not trimmed correctly. With the channel active you are getting 20% authority from the yaw channel to keep you pointed in that direction, but when you disengage it you lose that authority and a small imperfection in your trimm will send you spinning.

 

I arrested the rotation very quickly through a miniscule trimming.

 

The instability afterwards I cannot manage to replicate - I believe it's an input issue. But I am not actually sure it's anything wrong - slight instability when giving forceful rudder inputs is nothing strange, since the Pitch and Yaw channels will have less freedom to control cyclic when you have a strong yaw input and you thereby drift outside your auto-hover position which then causes the system to try to correct that but with imperfect control.

Edited December 16, 2009 by EtherealN

[159th_Viper]

In a perfectly trimmed Helo, would it also not be as a result of the Dissymmetry of Torque between the respective Rotors? The slightest variation would result in Angular Momentum manifesting - Stands to reason, No?

[EtherealN]

Well, you can compensate for it (though I haven't managed to make a completely perfect compensation), but obviously the difficulty is that if you are trimming while you have the AP Yaw channel active you will not be perfectly trimmed from the start, since the AP will be helpin you. The moment it's disengaged you get only your trim and find it erroneous. Pretty straightforward.

 

I'll make a trk for you Viper, just going to let the cat out first. :)

[EtherealN]

Here's two near-identical tracks - one with no wind and one with 10 meters per second wind.

 

In the first one disengaging the Yaw AP/Heading Hold channel causes us to rotate due to the slightly imperfect rudder trim that the Heading Hold was able to compensate for previously. After a revolution I make a slight trimming and is able to almost completely halt the deviation.

 

The second video is set up identically, but here we can see the wind stabilizing the helicopter in spite of the bad trim.

 

Moral of the story? Keep the Yaw channel active when hovering in zero-wind conditions and when hovering in wind conditions where you want to face in a direction other than the wind.

 

wolf_288, you can view those tracks if you want to see this in action and I hope this explains the phenomenon.

YawAP-0wind.trk

YawAP-10mswind.trk

[wolf_288]

EtherealN

Hi

if I have a stable hover and heading,how do I know my trimming was incorrect,you was writing (a small imperfection in your trimm will send you spinning)???

[EtherealN]

You don't.

 

The point is: do not turn off the Yaw AP channel! This issue will only be an issue if you insist on turning off that AP channel, something the real Ka-50 pilots are not allowed to do because there is no reason to do so.

 

If you disengage the Yaw channel anyway then you will have things like that happening. The function is there precisely to avoid such instabilities and of course when you disengage it you'll get unstable and have to manually compensate. ;)