Jet issues

[Zighator]

 

Hi, so i made this plane, i dont know what is wrong with it but it is realy unstable, at take-off it just starts to roll+ it strafes right when taking off. Can you please give me any suggestion on what to change as i realy like the design.. thanks

Edited February 13, 2016 by Zighator

[Foxster]

A picture would be handy. Chances are though that you haven't got the wheels perfectly aligned. 

[Choctofliatrio2.0]

26 minutes ago, Zighator said:

 

Hi, so i made this plane, i dont know what is wrong with it but it is realy unstable, at take-off it just starts to roll+ it strafes right when taking off. Can you please give me any suggestion on what to change as i realy like the design.. thanks

Wheels could be the problem. If it rolls once it leaves the runway, check where your Centers of Mass, Lift, and Thrust are.

[Scotius]

Wheels, or slightly off-center tail\control surfaces. Sometimes it's hard to place everything totally symmetrical, when you are going for a certain look

[Zighator]

The plane is full of control surfaces so they might be the problem :/

[qromodynmc]

So many wingy thingy.

I'd like to remind that overcomplicating wings always will hurt your plane.Use procedural wings instead.

 

 

 

[I_Killed_Jeb]

way too much wing... but that's whatever

 

i'd bet that it's your gears being mounted on your wings causing the wing flex at takeoff to veer you off

[SurrealShock]

The problem is that the CoL is way too far behind the CoM. Move it closer so it is partially inside the CoM. You can do this by changing the position of the wings. One other problem you might be facing is that the gears may be unstable on your craft. I usually just add a crap ton of struts to fix this because I have no real solution for this problem. :/ Make sure that the TWR is above around 1.2 also.

[I_Killed_Jeb]

4 hours ago, SurrealShock said:

The problem is that the CoL is way too far behind the CoM. Move it closer so it is partially inside the CoM. You can do this by changing the position of the wings. One other problem you might be facing is that the gears may be unstable on your craft. I usually just add a crap ton of struts to fix this because I have no real solution for this problem. :/ Make sure that the TWR is above around 1.2 also.

This is completely unnecessary and depending on the fuel tank arrangement can cause irrecoverable instability as the CoM shifts backwards.

[SurrealShock]

2 hours ago, I_Killed_Jeb said:

This is completely unnecessary and depending on the fuel tank arrangement can cause irrecoverable instability as the CoM shifts backwards.

Assuming that the fuel drains evenly throughout the craft according to the wiki: 

"

• COL ahead of COM → Flips or turns uncontrollably
• COL inside COM → Excessively maneuverable; needs constant course correction
• COL closely behind of COM → More maneuverable
• COL further behind of COM → More stable
• COL very far behind of COM → Very hard to correct course; likely to flip up or nosedive

"

[I_Killed_Jeb]

1 hour ago, SurrealShock said:

Assuming that the fuel drains evenly throughout the craft according to the wiki: 

"

• COL ahead of COM → Flips or turns uncontrollably
• COL inside COM → Excessively maneuverable; needs constant course correction
• COL closely behind of COM → More maneuverable
• COL further behind of COM → More stable
• COL very far behind of COM → Very hard to correct course; likely to flip up or nosedive

"

And the craft above has a perfectly fine CoM/CoL distance for all but the most acrobatic usage.

[Zighator]

Thanks for all the replies i made another less complicated plane which is stable and easily manuverable at the same time