Well, for starters, you are going to want to change the line name = fuelTank if you're trying to create a NEW part. Right now it has the same parameter as the default tank. The folder name is irrelevant and only affects how it's sorted in the VAB. To create a new part, you have to give it an original name. That's all I see that might be an issue. Cheers! Capt'n Skunky KSP Community Manager