Jump to content

POSSIBLE BUG: Plane turns left for no reason

MeepTicoMeep
 Share

Recommended Posts

XMaramena

XMaramena

Posted
Posted
On 06/12/2017 at 9:39 PM, MeepTicoMeep said:

So I've been making random  airplanes but when I fly them they randomly turn (yaw) left when I am trying to take off. There are no aerodynamic errors and I'm not pressing A. Help

If you look at the controls indicators, does it show your controls yawing to the left, or do they stay centered and the craft turns on its own?

Link to comment
Share on other sites
MeepTicoMeep

MeepTicoMeep

Posted
  • Author
Posted (edited)
On 12/9/2017 at 3:28 PM, XMaramena said:

If you look at the controls indicators, does it show your controls yawing to the left, or do they stay centered and the craft turns on its own?

the indicators are centered and the craft turns on its own through as the craft accelerates it appears to be yawing left on the artificial horrizon. 

I  tested a pre-made plane that is in the game (the dove) and it also yawed left.

Edited by MeepTicoMeep
Link to comment
Share on other sites
Gordon Fecyk

Gordon Fecyk

Posted
Posted

I've seen this behaviour with both FAR and Stock aerodynamics. I noticed it more on re-entry at a wild inclination, but I thought that was just me fighting the atmosphere as it rotated with the rest of Kerbin underneath my craft. Like a crosswind of sorts.

Question: Are you flying straight east or west while this happens, or some other direction? Is this more pronounced if travelling straight north or south? Does the craft yaw differently depending on which direction you're flying?

Link to comment
Share on other sites
Yakuzi

Yakuzi

Posted
Posted (edited)

There is a very common problem with the default friction parameters of landing gear that causes this behaviour. To work around this, right-click your front landing gear, override the friction control* and set it to a value of ~0.2... this should fix your issues.

If not, please provide some screenshots or, better yet, a craft file :)

 

* You'll need to enable "advanced tweakables" in the main settings menu.

Edited by Yakuzi
Link to comment
Share on other sites
MeepTicoMeep

MeepTicoMeep

Posted
  • Author
Posted
On 12/11/2017 at 10:29 PM, Gordon Fecyk said:

Question: Are you flying straight east or west while this happens, or some other direction? Is this more pronounced if travelling straight north or south? Does the craft yaw differently depending on which direction you're flying?

Im not flying at all.

 

On 12/12/2017 at 10:26 AM, Yakuzi said:

There is a very common problem with the default friction parameters of landing gear that causes this behaviour. To work around this, right-click your front landing gear, override the friction control* and set it to a value of ~0.2... this should fix your issues.

If not, please provide some screenshots or, better yet, a craft file :)

 

* You'll need to enable "advanced tweakables" in the main settings menu.

it did not work and here is the craft file download: http://www.mediafire.com/file/6z24brc2i2cnba9/Jet_Mk2.craft (site is safe just has lots of ads)

 

im starting to think it spawns already turned

Link to comment
Share on other sites
Gordon Fecyk

Gordon Fecyk

Posted
Posted
9 minutes ago, MeepTicoMeep said:

I'm not flying at all.

It would help if I read the question more closely. Sorry about that.

I have seen and experienced this before. This seemed to start with the traction and friction control mechanisms implemented starting with 1.1. My workaround was to turn the friction control of the forward-most landing gear from Auto to some value below 1.0. Just like Yakuzi is describing.

Where are the front wheels? On first load, I got this:

NoWheels.png

I moved the rear wheels to mount to the sides because the craft would roll left and right and didn't seem like it had a wide enough wheel base. Then I put a medium wheel back up front. Oddly, I didn't have to fiddle with friction control, but the craft would yaw slightly right. It still took off safely. Landing, on the other hand, I would ground-loop too much. Maybe setting the front wheel's friction control to less than one would still help.
NoWheelsV2.png

Here's the modified craft. (9 KB ZIP) I also added some struts; those side tanks were radially attached to the first passenger cabin and were flexing a bit to the rear. 

By the way, Media Fire tried to suggest my PC was out of date on the first click. And then it tried to keep its fake error message ad window open with modal dialogs; fortunately MS Edge has a "stop this site from doing this again" option on these. I don't call that 'safe.' 

 

Link to comment
Share on other sites
Yakuzi

Yakuzi

Posted
Posted (edited)
1 hour ago, MeepTicoMeep said:

it did not work and here is the craft file download:

im starting to think it spawns already turned

Thanks for the craft file Meep!

I had a look at the plane and there where some issues (besides the lack of a front wheel as @Gordon Fecyk mentioned above :wink: ):

  1. As Gordon mentioned, the most critical issue is that the rear wheels are too close to each other, resulting in severe oscillations and deviations in direction of the craft
  2. The rear part of the engine pylons are not strutted, causing flexing of the pylons and the landing gear attached to the pylons (you can clearly see this when the craft is first loaded on the runway from the SPH)
  3. When attaching the front wheel like Gordon's craft above, the nose of the plane is pointed down at an angle. While this increases down-force (think formula 1 car), it makes it harder to lift off, increases stress on the landing gear and compresses the springs, which can result in unwanted yawing on the runway
  4. The rear wheels had steering turned on, which can also lead to deviations in direction on the runway

I modified your craft to mitigate these issues (grab it here), and made some additional quality of life changes:

  • Rear wheels: disabled the steering, made the wheel base bigger then moved the wheels up and closer to the Center of Mass
  • Front wheel: changed the friction to 0.2
  • Engine pylon: autostrutted the trailing fuel tank
  • Wing type B: autostrutted this as well as it flexed quite a bit while flying
  • Control surfaces: disabled 'pitch', 'yaw' and 'roll' where they weren't necessary (this is also very helpful during flight)

Now the plane hardly deviates from the center of the runway, and you can take off at ~70 m/s by gently pitching up. I hope this helps, if you haven't done so already, be sure to read Keptin's visual guide on aircraft design, which is old but still very relevant!

yEMRJkz.png

Edited by Yakuzi
Link to comment
Share on other sites
Gordon Fecyk

Gordon Fecyk

Posted
Posted
9 hours ago, Yakuzi said:

When attaching the front wheel like Gordon's craft above, the nose of the plane is pointed down at an angle.

I was pretty careful about avoiding that. I raised the rear wheels when mounting them to the sides to give the craft a slight pitch upward.

Another thing that helps on takeoff is using those front canards as flaps. You may notice a right-click option for the canards that reads "Retracted." When you change it to "Deployed," they add more lift and can cause the craft to float off the runway at sufficient speed. You can also invert those to help plant the craft on the runway at touchdown, though it helps if the canards were mounted more parallel to the ground.

Link to comment
Share on other sites
This thread is quite old. Please consider starting a new thread rather than reviving this one.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
 Share
Go to topic listing
×
×
  • Create New...