Hello fellow rocketeers, hope you are doing well. As I kept designing my future rocket, one doubt came into my mind when looking at my BT and MMT. First of all, my BT is 1,968" OD and 1,85" ID; my MMT is 1,574" OD and 1,496" (38mm) ID.
The thing is, there is only left 1 3/8 or 1,377" (3,5 mm)...