ur not alone Atomicgoo i see this post every day asking same questions about mods.

u open the .xml save file for any plane. go to the engine u have saved on the plane alredy. change the max value from 1 to whatever u want. that is xml editing. we gotta come up with a new way to let new players no about this... let us end the elitist mod club and make it easier for new players to join

Through XML Modding.