Sapphire ~ Vintage EDF model by Peter Goldsmith (Build Thread by JimD)

[JimD]

Link to Peter Goldsmith Designs Web Page:

https://www.petergoldsmithdesigns.com/product-page/sapphire

Are you depressed about the FAA 400' ceiling news, then here is a little gem to brighten your attitude!

Peter has designed this model combining vintage looks with EDF propulsion and it is a (jet) blast to fly (around on the deck).

The first run kit was delivered to us at the Muncy, PA event last month and we started construction as soon as we got home...sixteen days later, a model ready to fly!!!!!

Span is 8', but weight is minimal for its size.

[JimD]

[JimD]

[JimD]

[JimD]

Items we used to complete our model (all parts available through Jeremy Hartmann (aka Swiss1) at The Model Box 2.0):

FMS 64mm EDF (FMMDF004)

FMS 40 amp ESC (FMMPAC113)

Spektrum (2) A5060 servos (SPMSA5060)

E-flite 3-cell 11.1 volt LiPo Battery (EFLB32003S40)

Hangar 9 UltraCote (3 rolls)

[Newman12]

Jim, on the 1/16 balsa TE on the wing, did you cut the root to wing tip taper to be right where the rib ends? (the plan pattern is a bit oversized so I'm trying to see how how sized yours) And where the two sheets meet did you bevel the edges of the sheets so that they fit together in a nice clean tapered edge?

[JimD]

If you look carefully at the plan, there is a side view of the stab/elevator. Note that the inside edges of the 1/16" trailing edge sheeting meet each other right at the end of the ribs and are finished so as to give a 1/8" thick trailing edge. You could build the wings as you describe and end up with a 1/16" trailing edge. Considering the size of the model, the 1/8" thick trailing edge looks like a knife edge from a few feet away. Having a thicker trailing edge makes covering and handling a bit easier too.

[FiremanBill]

Looks great. I just got started on mine a couple nights ago. I appreciate all the photos.

[JimD]

Let me know if you have any questions. 👍

[JimD]

Maiden flight success!!!

[jgallacher]

Looking good Jim

[Newman12]

How did you color your wood black Jim? is that a stain or something?

[JimD]

I used this acrylic paint (cleans up with soap and water)

https://www.horizonhobby.com/product/cars-and-trucks/paint/paint-and-accessories/acrylic-x18-semi-gloss-black-tam81018

[Swiss1]

We keep the full line of Tamiya paints at The Model Box!

[FiremanBill]

So I have mine all framed up. Still a few items to clear on the punch list but she looks great. Looking forward to getting it finished.

[JimD]

Nice work!!!

[JimD]

My initial flights were with the speed control located inside the fuselage just behind the battery. Following our two flights, we noted that the battery was just mildly warm as was the motor...but the speed control was HOT. We also found this arrangement was awkward because of the wiring between the motor and speed control which could not be unplugged easily.

Our fix was to relocate the speed control into the belly section (same location relative to the CG, just lower). This keeps the wires between the speed control and the motor in the same section. We cut the wire between the speed control and receiver and installed a connector. This allows the belly section to be easily separated from the fuselage body.

Next, we cut an opening in the covering between stringers in the front section to allow cooling air in. We had previously added a plate over the opening in the belly former in front of the NACA air inlets and added covering over this section to keep the fan from trying to suck air from inside the fuselage. About a 1/2" diameter hole was made in the plate and covering was added all the way forward to the speed control. This allows cooling air to be drawn in through the front section openings and for it to flow by the battery and the speed control and then out though the fan.

After two more flights at sustained full throttle, the speed control was now just mildly warm as was the battery and motor!

[FiremanBill]

Jim, What is this piece? I have mine all framed up now but did not come across anything like that.

[JimD]

There were two similar looking pieces in my kit. They form the rudder hinge line. One is the trailing edge of the fin and the other is the leading edge of the rudder. The slots are for the DuBro flat hinges.

[FiremanBill]

Oh ok now I see what they are. I used them in those positions as well. The pic just looked deceiving. Thanks, I feel better now!

[Newman12]

Also, you'll note that the slots are off center on one of the pieces and Jim was showing in his picture than he cut and added a little strip of balsa onto the side so it would even it out and then when you sand it to shape it will/should come out more even. It took me a while to figure out what that picture was all about and why he was showing it but then when I put mine together I realized what he was doing and it all made sense

[JimD]

Exactly...since my "kit" was a beta test run, I was not sure if this little error would be in any of the other kits, so I didn't make a big deal out of it. Sounds like it was in at least one other kit. Not hard to fix, ran into the same kind of thing with my Smellyak on the flap hinge parts. Cut a strip of balsa, glued it on, sanded as needed, good to go! It is what modelers do!

I think it is a test added in by Peter to see if we can figure it out! LOL