Hobby King Diabolo Canopy

The Hobby King Diabolo is an older EDF RC Jet that has been out of production for some time. A friend recently had the canopy come apart in flight and the resulting damage was not repairable. I created this model so he could keep flying this classic RC airplane.

The canopy is printed in three pieces, the forward, the aft, and a hold down tab. The forward and aft are printed standing up on end. I printed these pieces out of 3D LabPrint LW PLA (natural color). This material looks like normal PLA filament, however when it hits the nozzle it foams and creates very light weight parts. It's a little messy as the foaming action negates any attempts at filament retraction, so you will end up with lots of stringing and artifacts. This is not really a problem as it cleans up very easily and quickly and the completed model weight is less than half of regular PLA. This takes unique filament and printer configuration files and 3D LabPrint has all the info on their site to create your own (my preference), or config.ini files for download.

The hold down tab is printed out of regular PLA. I printed all parts at a layer height of 0.20 mm with a 0.4 mm HF nozzle.

Once the parts are printed there are three tooling holes which aid in the alignment of the forward and aft canopies. I used (3) short pieces of 1.5 mm carbon fiber rod as pins and used DAP Rapid Fuse CA to bond the parts together. The DAP Rapid Fuse gives you about 30 secs to adjust your alignment before it sets and responds well to CA kicker, however if you use kicker it is likely to "yellow" the parts.

To get a nice finish and fill the layer lines associated with printing the parts I use Deluxe Easy Coat to fill the lines followed by wet sanding (dry sanding will usually end up making the PLA ball up due to the surface heat generated by sanding).

The hold down tab is held on by (2) #2 sheet metal screws.