What is wrong in my plane?

[Pawelk198604]

I have the game for long time since it's inception but planes have always bit hard for me  

 

I wonder what i did wrong? 

 

i have always problem with placing control surfaces on planes 

 

[Caerfinon]

15 minutes ago, Pawelk198604 said:

but planes have always bit hard for me

I found this guide to be extremely useful when I started building my first planes. Have a look and compare to your aircraft to see what improvements can be made.

 

[king of nowhere]

problems on the runway are often caused by wheel drag: wheels cause drag, and if the front wheel(s) is causing more drag than the rear ones, then the plane tends to flip on the runway. you can fix that by manually changing the friction for all wheels

[AHHans]

3 hours ago, Pawelk198604 said:

I wonder what i did wrong? 

The engines are quite a bit above the center of mass, so when they run they will push the nose down. And you apparently don't have enough torque to pull the nose up against the torque from the engines.

In addition:
- Nearly all your control authority in pitch and yaw on this plane is from the reaction wheel (== magic) torque of the cockpit. That would probably be O.K. if the plane was balanced otherwise, but it isn't when the engines generate significant pitch-down torque.
- The two ailerons that you placed are more or less in-line with the center of mass, so they won't do much for pitch except increasing drag. So you might want to disable pitch control on them. (They are placed well for roll though!)
- I guess there is a reason why you don't have any control surfaces on the tailplane, but I wonder what that is.
- The springs on the main landing gear are bottoming out - you can see the wheels coming up through the to side of the fenders. This makes the gear extra jumpy, which in turn makes it harder to control. It will probably roll better if you increase the spring strength so that the wheels are in the middle, with the spring somewhat compressed but not all the way.

 

3 hours ago, Pawelk198604 said:

i have always problem with placing control surfaces on planes 

Welcome to the club!
My solution is tho just place the control surfaces in about the right position, and then manually rotate and move them into place. Trying to get it right by attaching them at the "correct^(TM)" place is IMHO an exercise in frustration.

[Vanamonde]

The control surfaces are so close to the COM that they have almost no leverage. Replace those tail pieces with pivoting alternatives. It will also help if you lower the engines so they are not applying nose-down torque, and adjust the landing gear heights so that the plane sits with a slight nose-up attitude. That last is because KSP airfoils only generate lift if they have an angle of attack to the air flow. So if the plane rests nose-up, they will begin to generate lift as soon as it moves. 

[herbal space program]

Echoing what others have said, move your engines down so they're not pushing you into the ground. Also move your rear wheels back so they're a little behind your CoM instead of in front of it, and displace your nose wheel a bit forwards and downwards, so your plane is pointing up a little. Rotating your wings so they're pitched up just a tiny bit would help too. You're still probably going to have problems with that very long tail piece though. I might replace that with a NCIS adapter full of fuel, which would also let you move your wings further back so they don't block your cockpit hatch. It would moreover let you move your rear wheels further back to reduce the danger of a tail strike on takeoff.

Edited June 9, 2021 by herbal space program

[Echo__3]

https://www.reddit.com/r/KerbalAcademy/comments/h96cpa/lets_discuss_airplane_design/