- Apr 5, 2013
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Sr-71B 1:45 build thread
- Thread starter abdullahsamir
- Start date
I found this video on Youtube, it is quite detailed for an animated tour.
It even goes thru how the inlet spike, and inlet system provide more thrust at cruise than the engines.
It even goes thru how the inlet spike, and inlet system provide more thrust at cruise than the engines.
Alright, here we go! 
You need a connection between the circles so that they keep their position.
The most efficient way is this:
Please note that I am using a totally asymmetrical model in these pictures to show you that this technique can be applied to all sorts of different shapes. Things will be much easier if you have a symmetrical piece but it really doesn't matter.
Intersect all former faces with the model but make sure that you intersect the ungrouped face. Otherwise you will end up with intersecting lines floating outside the groups. The intersecting lines must be on the face in question to be able to remove the unneeded areas.
Offset each circle compensating for the paper thickness and delete the unneeded area.
When you have intersected and cleaned up everything draw an additional horizontal or vertical face that goes straight through the middle of the model. Group the new former.
Hide the circular formers. Select the diagonal former. Intersect with model. Offset the shape as seen above. Clean it up:
Make the circular formers visible again and hide the model shape.
Intersect all formers with each other:
These lines serve as placement guides for interlocking and positioning the formers.
Now there are two ways to proceed. You can either edit the formers in 3D or on the canvas in your favourite graphic program. Chose whatever is best for you.
Editing in 3D:
Pull out a guideline and put it into the center of the long former:
Now draw a rectangle of the suggested width of the former. I would go with 1mm. Group the rectangle.
Move this rectangle around the former until the center meets the crossing point between intersection and guideline:
Create duplicates of the rectangle and proceed with the other areas:
Create another duplicate of the rectangle and turn it 90°.
Go back to the circular formers and proceed accordingly, but this time make sure that the rectangles are above the guideline.
Ungroup everything so that the rectangles become part of the formers.
You need a connection between the circles so that they keep their position.
The most efficient way is this:
Please note that I am using a totally asymmetrical model in these pictures to show you that this technique can be applied to all sorts of different shapes. Things will be much easier if you have a symmetrical piece but it really doesn't matter.
Intersect all former faces with the model but make sure that you intersect the ungrouped face. Otherwise you will end up with intersecting lines floating outside the groups. The intersecting lines must be on the face in question to be able to remove the unneeded areas.
Offset each circle compensating for the paper thickness and delete the unneeded area.
When you have intersected and cleaned up everything draw an additional horizontal or vertical face that goes straight through the middle of the model. Group the new former.
Hide the circular formers. Select the diagonal former. Intersect with model. Offset the shape as seen above. Clean it up:
Make the circular formers visible again and hide the model shape.
Intersect all formers with each other:
These lines serve as placement guides for interlocking and positioning the formers.
Now there are two ways to proceed. You can either edit the formers in 3D or on the canvas in your favourite graphic program. Chose whatever is best for you.
Editing in 3D:
Pull out a guideline and put it into the center of the long former:
Now draw a rectangle of the suggested width of the former. I would go with 1mm. Group the rectangle.
Move this rectangle around the former until the center meets the crossing point between intersection and guideline:
Create duplicates of the rectangle and proceed with the other areas:
Create another duplicate of the rectangle and turn it 90°.
Go back to the circular formers and proceed accordingly, but this time make sure that the rectangles are above the guideline.
Ungroup everything so that the rectangles become part of the formers.
Clean up the parts:
So it is possible to interlock the formers. If you do not cut the incisions too big everything will hold together by friction, so no glue will be required.
Editing on the canvas:
If you decide to edit the unfolded pattern in the graphic program make notes which one goes where. It's important to note that the parts may be exported upside down, so if necessary rotate them on the canvas.
I recommend to make the edits in a graphic program after unfolding ONLY if you are working with straight-forward and easy shapes which are easily identifiable (and preferably symmetrical). It is much safer to make the edits in 3D because then you do not switch the orientation of the parts and cuts later by accident.
The basic principle is the same: Create several small rectangles of 1mm width, move them into the crossing centers and "punch out" the rectangles from the formers.
Well then. With all formers prepared it is important to know how they are inserted into the finished piece. Of course they have to be put inside the model shape BEFORE it is closed. Usually there is an opening which can be used to push them in. However, in the example I am using here both ends of the model become smaller than the middle section. Again, I chose this to show you how you can deal with that sort of shapes.
Paper tolerates a bit of flexing, bowing and bending, so it may be able to gently force-pull the hull over the formers or to rotate the vertical and horizintal formers in order to squeeze them into the hull, similar to inserting a bottle ship. Of course you have to make sure that no element is permanently creased or bowed. If a former piece does not fit properly you may solve that by rotating it slightly to make it fit (no-one cares about how everything looks inside once the model is closed up ).
However, in the case above none of the strategies are applicable because bothe ends are too small for the center piece and you are dealing with already closed elements (cones) which are pretty tricky to close after inserting the formers.
So assemble the hull as much as you can, leave an opening which is big enough for the skeleton, push the skeleton inside and then add the other hull elements to close the shape:
I hope this helps!
So it is possible to interlock the formers. If you do not cut the incisions too big everything will hold together by friction, so no glue will be required.
Editing on the canvas:
If you decide to edit the unfolded pattern in the graphic program make notes which one goes where. It's important to note that the parts may be exported upside down, so if necessary rotate them on the canvas.
I recommend to make the edits in a graphic program after unfolding ONLY if you are working with straight-forward and easy shapes which are easily identifiable (and preferably symmetrical). It is much safer to make the edits in 3D because then you do not switch the orientation of the parts and cuts later by accident.
The basic principle is the same: Create several small rectangles of 1mm width, move them into the crossing centers and "punch out" the rectangles from the formers.
Well then. With all formers prepared it is important to know how they are inserted into the finished piece. Of course they have to be put inside the model shape BEFORE it is closed. Usually there is an opening which can be used to push them in. However, in the example I am using here both ends of the model become smaller than the middle section. Again, I chose this to show you how you can deal with that sort of shapes.
Paper tolerates a bit of flexing, bowing and bending, so it may be able to gently force-pull the hull over the formers or to rotate the vertical and horizintal formers in order to squeeze them into the hull, similar to inserting a bottle ship. Of course you have to make sure that no element is permanently creased or bowed. If a former piece does not fit properly you may solve that by rotating it slightly to make it fit (no-one cares about how everything looks inside once the model is closed up
).However, in the case above none of the strategies are applicable because bothe ends are too small for the center piece and you are dealing with already closed elements (cones) which are pretty tricky to close after inserting the formers.
So assemble the hull as much as you can, leave an opening which is big enough for the skeleton, push the skeleton inside and then add the other hull elements to close the shape:
I hope this helps!
For some reason mine always needs a LOT of cleanup, but hey it works now and I have a good skeloton!!! THANKS a ton RF!!!!!!
