Ziroli Panther RC Jet Air intake duct molds

In 2018 I have built the Nick Ziroli design Grumman Panther F9F-5 model as my turbine trainer, which to date I still enjoy flying, with more than 70 flights in total. This model is a conventional balsa/plywood construction model, however during my build, I have used 3Dprinting technology extensively both to assist my build and also make some functional parts to be used on the model itself.

I am sharing some of my related designs here for others to use in their builds of this beautiful model.

This particular post includes my design for the air intake duct mold.

I designed this part to connect the air intakes at the leading edge of the wing roots to the intake of the turbine at the centre of the fuselage. The ducts are designed to be placed in without a necessity to significantly cut the major formers of the fuselage at this area as this is the core structure of the airframe and should be built/kept as strong as possible.

This mold is a sacrificial mold, i.e. once the duct is produced around the 3D printed mold, it is broken into pieces to be removed from the inside of the produced fibreglass air duct.

Once the mold is printed, apply mold release to the outer surface, wrap it with fiberglass fabric and lamination epoxy and let to cure. When cured, start from one edge and carefully break off the 3D printed plastic to remove it from inside. If you use PLA you may "bake" the part at 50-60 degrees to soften the PLA and ease the removal process.

I used 3 layers of 100 gr/sqm fibreglass cloth if my memory serves well.

The inside end of the ducts are large enough to provide bypass air over the turbine and exhaust pipe for cooling purposes.

You may see my related posts on my Instagram:

https://www.instagram.com/p/BoBDtDgFasZ/?utm_source=ig_web_copy_link

https://www.instagram.com/p/BoBSucTlL-f/?utm_source=ig_web_copy_link

https://www.instagram.com/p/BoBxzf3l8og/?utm_source=ig_web_copy_link

https://www.instagram.com/p/Bo1Qjftlt_y/?utm_source=ig_web_copy_link

Note: It might be possible to use the part directly instead of using it as a mold, however, I was not completely convinced that it would be strong enough not to collapse under the powerful suction of the turbine engine, and chose to use it as a mold.

Print with 0.15mm layer height at the maximum. This will provide a smooth surface and also allow for supportless printing.

Print as just perimeters, 2 should be fine, can be made 3 too. No bottom no top no infill. Just perimeters.

Adding a couple of millimetres of brim is helpful due to the shape of the duct.

Don't forget that you have to print a mirror image for the other side.