Q2/200/260 foam planked fuselage jig update

[Justin]

Hi Folks,

This is progressing, and it is becoming quite a complex assembly, so it is worth making the whole system reusable. I uploaded a CAD update at  https://grabcad.com/library/quickie-q2-fuselage-jig-april-26th-2023-1   .  It is only the jig. All the previously uploaded planks are unchanged.

I foresee that all the formers will be water or laser cut.

The new plank layout gives an assembly order of planks that adds dimensional stability to the assembly, and parts of the jig structure can be progressively removed to allow the second and final planking operations.

First the upper planks, down to the waist line are added. Then the jig is turned over; possibly on axles from the ends of the spine parts. BTW, the spine is a 4" square aluminium extrusion, with a smaller 2" x 2" tail extrusion.

When the assembly is  upside down the former support struts at FS146 and FS158 are removed. Then the bottom planks are added.

Next; the 'helicopter skids' all the former support struts are removed, and the remaining side planks are added.

Then the planks are faired and the skin laminates added.

I will work next on how the foam core with the outer skin is separated from the jig formers and spine. The process will be to make the fore - aft fuselage split, and the top and bottom tailcone split. The spine can be extracted, and most formers can be extracted. It looks like the cockpit area formers at FS 53.5, FS63, and FS74, will need to be made in two parts, to enable extraction.

After this the internal foam surfaces can be cleaned up and skinned. I still see no need for the main fuselage part to be split at the waist. It will be open at the ends, and where the canopy frame core is cut out.  Until the inner skins are added there will be a need for some simple external cradling to ensure accuracy.

So... there is some more work to do !

Here are a few pictures.

 

[Anthony P]

Very nice work!

Tell me about the need for two "helicopter skids".  Especially if you create a rotisserie through the main spine.

Seems to me that one strong back or, "heli skid" could come directly down from the bottom of the formers which would allow for more/easier planking.

One of the most effective ways to maintain parallelism between formers would be equal length "sticks" (20mm x 20mm x ? pine) screwed between formers near the outer edges.

[Justin]

Thanks Anthony,

Interesting comment on the helicopter skids. I think the jig is a developing design. The skids and struts are there to add dimensional stability to the formers, but if the spine part is made with aluminium extrusions I could foresee that the skids and struts could be replaced by extruded angle brackets bolted directly to the spine. As the foam planks are added these brackets are removed, to ensure ease of jig extraction from the finished core with the external skin.

Hmmm....

[Jon Matcho]

Amazing work @Justin

I'm a fan of a rotisserie with temporary dimensional supports.

Quite amazing, and thank you for sharing!