Seeker, Thanks for your advice. I will integrate it.
I am going to cut the ribs in half later, adjust till it allow the last surface of this six sided engine could close, then glue the two halves of the ribs back with an additional piece to cover the gap which I failed to cater before.
The ribs were only 4 sided. I was pretty lost on how to construct all six sides as I couldnt derive the angle required on the remaining 2 sides. On top of that, due to the sloping shape, some ribs have to start small, some bigger ones in the middle, then slightly smaller again at the end.
For the rib, I am using 1.0
Some nights I look at it and am totally brain dead.
Will spend some hours into it later today.