I'm pretty sure of that. My question to the inker {you should see the plans of the Sukhoi I'm building now} would be how or from what do they used to ink the plans?? Was he drinking/drugging while he was drawing these plans?? Is a true 1/4 inch notch too hard to draw?? Should not a symmetrical rib not be the same shape if you flip them over?? Just little questions.