sahartman21

The Napier is getting a few changes for 2014.

These include:

1) larger tail surfaces
2) more wing span

The Napier is a fiberglass, carbon, and foam kit. If you want to build a fast model and not spend much money, give one of his kits a try.

http://www.matneymodels.com/qm.html

fizzwater2

My Feedback: (61)

Looking forward to watching this build!

sahartman21

Here are some drawings showing some of the details:

sahartman21

The following pictures shows the installation of the motor mount into the nose.

The engine cylinder will be canted downward to lower the venturi. It's been my experience this helps the performance of the engine.

1) Trace out the cutout pattern and then cut it out.
2) Test fit the engine in the nose.
3) After you are satisfied with the fit the firewall is installed.
4) Tack glue the motor mount to the firewall.
5) Remove the engine and then begin drilling the holes for the mounting screws.
6) Remove the firewall and install the engine kill. I'm using a 3/8" OD diameter piece of aluminum tubing.
7) Roughen up the fuselage inside surface using a Dremel tool.
8) Install the blind nuts in the firewall.
9) Smear Vaseline over the backside of the motor mount.
10) Apply some 30 minute epoxy over the firewall and back of motor mount.
11) Re-attach the motor mount to the firewall and then install them inside the fuselage.
12) Install the engine on the mount. Add a 1/32" plywood spacer and then add the spinner. Tape the spinner to the nose of the fuselage.
13) Add some cotton flocks to the epoxy and apply to the backside of the firewall glue joint.
14) Make sure the engine is still straight and set parts out of the way to dry.

sahartman21

Continue the engine mount installation by anchoring the front to the fuselage.

Roughen the area with a Dremel tool.

Vaseline some screws prior to installing them in the motor mount.

Cut some pieces of fiberglass cloth and add to 6-minute epoxy.

Dab the mix in place.

Use a wet finger to shape the mix for a smooth surface.

sahartman21

I planned the landing gear installation so that the wheel axel is located about 5/8" in front of the CG.

1. Sketch out the location for the landing gear block.
2. Identify where the spars will be located.
3. Confirm that the location of the carbon fiber reinforcement is not in the way of the landing gear block.
4. Cut the slots with a radial arm saw or equal.

Following are pictures showing the fabrication of wing skins. I make them about 1" wider than the wing cord and about 1/2" longer. This allows some room to fit skins to the cores.

1. Begin by making a jig with large pins being the wood cut points.
2. Place balsa sheets at the leading and trailing edges.
3. Follow with one more sheet in the middle.
4. Pin sheets in place and then use a very sharp model knife to trim parts to fit.
5. Take the triangle shaped piece from the middle sheet to makeup the remaining are in the middle.
6. Tape the sheets together and cut parts to make the final wing skin.

You will need 2 of the original skin and 2 mirror image skins.


The mirror image skins are made similarly. Temporarily tape the cut out skin together and then turn the skin over. Follow by taping skins together on the alternate side.

The last picture shows the approximate location of the carbon fiber strips.

sahartman21

The landing gear support/spar were fitted and cut in the following pictures.

I've used hard balsa, although lite ply or plywood should also work fine.

sahartman21

Wing skins are being joined with masking tape in the following photographs.

sahartman21

Carbon fiber laminate (7 thousandths thick) is temporarily attached to the skins with 3M77.

sahartman21

The leading edge is being made with carbon fiber tow.

Approximately 8 widths of 12,000 pound tow is used.

Finishing epoxy is applied to the tow prior to going to the next steps.

sahartman21

Finishing epoxy is applied to the carbon fiber top spar (20 thousandths laminate).

Finishing epoxy is applied to the spars.

Parts are slipped in place after applying the epoxy.

sahartman21

Mix approximately 1 ounce of finishing epoxy and apply to the skins. I thin the epoxy with a cap of 91% alcohol.

Apply and use a squeegee to spread out the mix to one side of the wing surface.

The other side is done the same way.

sahartman21

The core is laid between the bottom and top wing sheeting.

Align the sheeting and pin the parts in place.

Lay the parts between the shucks and pin parts in place.

Apply masking tape around the parts.

Remove for any sharp pins sticking out.

Place parts on top of a 4 mill thick piece of plastic tarp.

Tape a piece of rope in front of the wing cores. Tape the vacuum hose in place.

Apply a bead of latex caulking around the outside of the cores and close the bag.

Place a couple quart cans of paint or equal on top and turn on the pump.

It was a little too cool so the parts were placed inside an electric blanket to warm up the surface.

Hobbs88

Scott,

Can you explain a little more about the Carbon Fiber Leading Edge? The carbon fiber appears to be behind/underneath the upper & lower sheeting, is that correct?

Thanks,
Ben

fizzwater2

My Feedback: (61)

Ben - I'm sure Scott will have a more detailed answer than I, but I think in general you trap a wad of carbon fiber tow with epoxy between the skins where they overhang the front of the core - then after it's cured, sand the LE shape with a long sanding bar to make a nice rigid leading edge that would be a little more ding resistant than a shape balsa leading edge.

sahartman21

Ben,

1) You order or cut cores based upon having a 1/8" thick leading edge.
2) I joined the skins at the leading edge with masking tape.
3) A layer of 1.6 ounce fiberglass cloth is placed on the skins.
4) Approximately 6 to 8 lengths of carbon fiber tow are used and are placed at the fold between the top and bottom skins.
5) Apply finishing epoxy to the tow and skins.
6) Wrap the skins (with the tow at the leading edge) around the cores.

sahartman21

The wing was removed from the vacuum bag.

Double check the alignment of the cores and the shucks. This is verified by insuring the marker line is straight across the shucks and cores.


Mark a line about 1/8" in front of the shuck at the leading edge.

Use a hobby saw and trim the leading edge at that line. Use a sanding block to insure the edge is straight.

sahartman21

I used lightweight spackle to fill any gaps and holes present on the wing surface.

sahartman21

The following pictures show the installation of landing gear blocks.

sahartman21

I fabricated the wing tips from 1/4" and 3/16" lightweight balsa sheets.

Between the balsa is a piece of fiberglass cloth.

The tips were glued on with 5-minute epoxy.

After the glue dried the tips were shaped with knife and sanding blocks.

The trailing edge was sanded to a sharp edge.

Sand the wing as needed.

sahartman21

Mask the gear location to keep epoxy out during fiberglassing.

Plan out the installation of the ailerons. These start about 6" from the center line of the wing. Each will be about 11" long.

Adding dowel reinforcement to the wing is next.

The pictures show the sequence:

sahartman21

Apply a thin layer of finishing epoxy.

Place a piece of hinge material (taffeta or nylon fabric about 1" wider than the ailerons) on the wing surface.

sahartman21

Tack the wing surface with 3M77. Apply1.6 ounce fiberglass cloth on both top and bottom sides of the wing.

Tack the wing tips with 3M77 and apply a second layer of fiberglass on top and bottom of the wing tips.

Tack the center of the wing as before and apply a 14" wide piece of fiberglass cloth.

Follow with a 9" wide piece of fiberglass cloth.

Then follow with a 5" wide piece of fiberglass cloth.

sahartman21

Mix about 1.25 ounces of finishing epoxy. Add a cap of 91% alcohol to thin the mix.

Apply epoxy to a wing section. Use a squeegee apply the epoxy to the surface. Turn the wing over and do the opposite side.

Mix some more epoxy and apply to the opposite side of the wing. Turn over and apply until all fiberglass cloth is damp.

Cut a piece of peel ply (shinny nylon or nylon polyester fabric) large enough to cover both sides of the wing.

Wrap the wing with the peel ply.

Place parts on the vacuum bag (4 mil thick tarp). Lay a length of paper towel over the bottom surface of the wing. Put a length of 1/4" rope or equal on the back side of the cores.

Tape the vacuum hose to the inside of the bag. Lay a bead of cheap latex caulking around the parameter of the bag. Close the bag.

Remove the majority of the air from the bag using the pump. Place the bag between the shucks. Apply a couple quarts of paint or equal on top.

Turn on the vacuum pump and apply about 6" of Hg vacuum.

It was cold outside so parts were covered with an electric blanket. That allows the epoxy to dry.

sahartman21

The wing was removed from the vacuum bag and the peel ply was removed from the surface of the wing.

Use a sanding block to trim the fiberglass cloth from the edges.