model collision

In my game,there is a paraglider model here in the blueprint.However,the model consists of several models,that is,it’s not a whole stuff.The umbrella model,the seats model,the fan model were put together to make the paraglider.
Now the problem is that it seems these models collide with each other when they simulate the physics which cause undesirable bad effects.I do need them to simulate physics.Nevertheless,the collision effect is unbearable.
So I am wandering if there is a solution to this problem.

Can you combine the models in an external editor?? Seems like the easiest way.

Or you could setup collision channels that make them ignore eachother.

Thank you very much ,DevilsD.