Aircraft Pitches Up Violently On Takeoff

[dusky zenith]

Hello,

Recently, I was able to make my own plane with realistic aerodynamics by following Suphi's Flight Physics Tutorial. The diagram for said plane is shown below.

Problem

• On takeoff, after the first pitch-up input, the aircraft will start looping around until eventually crashing. This behavior can be seen here

Question

• Is this a scripting error, or is my flight model flawed? (I'm not an Aerospace Engineer yet)

Note that

• If this is a scripting error, I will provide the client source code for further investigation.

Thank you for the help. I am looking forward to any responses! 🛩️

[steady orchid]

this looks like a simple plane design issue, where the center of mass is too far behind the center of lift

so everywhere behind your center of lift will experience a stronger influence from gravity, which in turn pulls down the back of the plane and pushes up the front like a seesaw, with the pivot at the center of lift

a lot of this will be trial and error, but some things you can try are:

• increase the mass at the front of the plane
• decrease the mass at the back of the plane
• increase the surface area of the parts and/or elevators at the back of the plane

if you havent heard of kerbal space program or dont have it, i highly recommend getting the game and playing around with planes via the spaceplane hangar, where you can see the center of mass, thrust, and lift and see how those interact

generally, for a stable plane youll want the center of lift slightly behind the center of mass so it tilts down a little bit as it flies, but not too far down

[dusky zenith]

Thanks for the detailed response! I'll be sure to implement your fixes and report back. Also, thank you for the sim recommendation, it sounds exciting. 👍

[steady orchid]

looks like its 75% off right now which is cool

[dusky zenith]

Great timing 😄

[steady orchid]

if you do decide to get it, make sure not to get ksp 2
the original kerbal space program is much better and actually works

[dusky zenith]

Ooh, good thing I'm hearing this now

[steady orchid]

yeah ksp 2 never left early access and is still on steam despite nobody working on it
so ignore that one

[dusky zenith]

Also, side note, it's working now! Thanks again for the help :)
Plane is fixed!

I'm going to work on the rudder control now

[steady orchid]

nice!

[dusky zenith]

Ah I see

Good to know