Junkers Ju390

[Mr Speedy]

Hi Dave! Good to see you here too! Hopefully that means that you are coping with your challenging situation?     
    Yes, it's nice to be back on HPA! I've got a bit more time now, so I'm trying to round up my " ducks 🦆 ", in an attempt to get them into a row! But hopefully that will mean cutting wood soon!   It's cool that someone photographed your plane flying and the photo wasn't lost!      I'm watching with interest as usual!!

[dputt7]

Progress has been a bit slow lately but I have managed a bit.
Made up the 2 outer wing panels Photo 1.  Photo 2 shows the outer wings carved and sanded.  The out panels will be made detachable for transport and mainly to prevent damage in a hard landing.
In Photo 3 the dihedral is set and 1/8th brass tubes are set in place against the spars. A wood spacer with slots to clear the brass tubes is clamped in place between the root ribs and the tubes glued in place.  Photo 4 shows the balsa glued against the tubes, these will be filled with glue and vertical grain gaps glued in place over the tubes.

[dputt7]

  The Root ribs are faced with 1mm ply and then sanded Photo 1
The center section has the root ribs faced as well and I have sheeted the front of the wing and have added sheet for the nacelles. I should have thought about this when I laid out the ribs and spaced them to suit the nacelles, it would have been neater. Photo2.   Finally the completed wing so far. Photo3
                                               Dave

[dputt7]

  Hi, next step is the mounts for the motors. As the wing is set at 3degs. positive Incidence I wanted the motors to sit level with the fuse so they already had 3degs. downthrust relative to the wing. the motors will be adjustable so I have drilled the motor mounts above the center line so I can increase the downthrust if required and the prop shaft will be in the center of the cowlings.
  To this end I made up a jig with some brackets set at 3degs.to hold the wing in place, the ply mounts could then sit squarely on the bench while the epoxy dried. Photo 1.  Photo 2 shows the completed motor mounts while Photo 3 shows the underside mounts and gussets as well as the strips for mounting the lower Nacelles.  Next up is making the inner Nacelles.  in Photo 4 you can see the jig I made to hold the form in place. The inner Nacelle has a bulge on the lower side to contain the landing gear so I spun the form into shape on the lathe. I then cut off the lower third and replaced it with a block of balsa and carved it to the bulging shape. I then mounted it in the jig with the underside up and molded a lower nacelle. I the removed the screws and turned it 180degs. to mold the top Nacelle.

[dputt7]

  Here are the Photos

[OZPAF]

That's a neat clever approach to making the nacelles and jigging the motor mounts, Dave.

Happy building.

John

[dputt7]

In Photo 5. you can see the setup for the Outer Nacelles.  As they are the same upper and lower I spun up the form in the lathe and mounted it so I could form the Nacelles, Finally Photo 6 shows the top inner and outer Nacelles in place.

[dputt7]

  Thanks John.

[Lastwoodsman]

Wed march 25 2026

     Hi dputt7  Dave.   That is a very interesting and excellent build of your six engine Junkers Ju390 plane!           Thanks for all of the pics and info!

Lastwoodsman
Richard

[dputt7]

   Thanks for your interest Richard