Build Articles
K & A - MIG-15 EDF (Part 2)
By Carl Tulanko
October 15, 2006 - 07:00:02 PM

6oz glass cloth is taped to the duct as shown	Medium CA is used down the side to anchor the cloth for glassing	A good glassing resin such as West Systems is used to glass the cloth to the intake
The intake is wrapped in a plastic sheet and left to set	The sheet is removed, the end caps are removed and the ends are trimmed while the epoxy has set but is still soft. Keep an eye on the inside for epoxy dripping, which actually seaped through pinholes in the thin intake tube material during the glassing process. Keep it clean with denatured alcohol and a paper towel so you don't have these bumps and drips to deal with later	Once completely dry, remove the inside packing tape. A piece of 1/2" wide masking is installed down the center of the fan housing and the intake is installed flush to one end of the tape and held temporarilly in place with packing tape or electrical tape
The intake side needed some sanding to make it flush	The intake tube is sanded flush to the fuselage front	The forward former is installed next and you may have to sand down the center so the intake tube fits from front to rear. It is best to do this before gluing the former in place. Be sure to take off a little at a time and deepen the center. You can use the template to insure it stays round at the bottom

The fuselage is roughed up with 60 grit sandpaper about 1" wide, centered over the front former area	The former is tack glued using 5 minute epoxy, with the rear of the former on the marks you made earlier. Then it is glued and glassed in place with 1" wide x 6 1/2" wide strips of glass cloth. Crosscut your cloth at 45 degrees from the weave so it can accordion easily and be shaped to fit around the curved area. Clean up any excess epoxy	For the MF480, one end of the exhaust tube is lightly trimmed to straighten the cut from the manufacturer. If you are using a larger fan, omit this and the next several steps and proceed to glassing
The smaller end is taped flush using masking tape	A piece of masking is used to "space" the duct away from the fan housing. This is to allow room for a smaller plastic fim exhaust duct to be installed later and is only for the Minifan 480. For the larger fans, you can omit this step	For the MF480, the duct is installed on the housing and taped tight. Then a mark is made on the unevenly cut side of the duct at the overlapped area
The other uneven side of the duct is cut away from the mark	The piece is shown removed	The tube is held flush at the ends with masking tape. If necessary, lightly sand the two edges so they are flush all the way down the tube

Packing tape is used on the inside to hold the two edges flush	A wooden dowel is used to push the packing tape down on the inside where you cannot reach	The excess tape is removed with a razor
The outside masking tape is removed and a couple of layers of masking are used on the inside ends for drips	The tube is taped to your working surface so it is easier to glass	An area is sanded about 3/4" wide on each side of the seam
Glass cloth shown is cut to about 1 1/2"	Epoxy resin is applied to the seam area of the exhaust tube	The cloth is layed over the resin area and pressed down

Resin is brushed on the top of the cloth to make sure it is saturated	The excess resin is removed with a spreader and the tube is left to set	The seam was sanded to remove excess epoxy and keep it light
A ring is made from 1/16" ply to fit in the end of the fiberglass tube and the inside is cut to 55mm diameter	A piece of clear 5 mil Dura Lar used as an inner thrust tube for the Minifan is cut oversized, then inserted in the glass tube at the fan side and trimmed flush to the end	Masking tape is used to hold the inner liner flush with the fan end
The ply ring is installed and the inner thrust tube is cut flush with the fiberglass tube at the exhaust end	Apply masking to hold the tube in place, then cut a 1" wide piece of clear packing tape and seal the tube seams inside and out	Inner thrust tube assembly completed

A mark is made 1/2" from the edge of the tube	3/8" Washers on each side of the plastic make cutting a hole easy	Hole is shown cut for ESC wires
Wires are inserted through the hole	The tube is slid 1/2" over the fan housing and taped in place	Fan assembly and inner thrust tube completed
The fiberglass thrust tube is marked to slot it for the ESC wires	The slot is 7/8" deep and 1/2" wide and rounded at the edges	The fan asembly and inner thrust tube slide into the outer glass thrust tube

The tail end of the fuselage should be checked for round and sanded straight if necessary	Tail is shown sanded and ready	Location marks are made 4 3/4" from the tail for the rear former
Fine sand the former until it fits flush	60 grit sandpaper taped to your finger makes it easy to sand the inside of the fuselage area for the rear former	Once sanded, clean the dust off with alcohol and a towel
Thirty minute epoxy was used to glue the former in place and a fillet mix of epoxy and fiberglass mil was applied to the joint	Coat four of the 1/8" thick x 1/2" ply squares with CA on one side	Sand the CA side and round the corners on the squares

Drill a 1/8" hole in two of the squares and a 3/16" hole in the other two squares	Photo shows all four squares prepared and ready to use as retainers	The 3/16" and 1/8" wood dowels are pressed into the wing to make a guide hole. Keep the dowels square to the root
Epoxy is applied to each hole using a toothpick	The wood dowels are inserted and kept square with 1" protruding	The dowels for the second wing are installed
Photo shows all wing dowels installed	The wing root is roughed up with 60 grit sandpaper	Wing root is ready to final prep for wing installation

Drill holes as shown with a 1/8" bit to allow for better glue adhesion	The wing spar is also drilled as shown	The outside of the fuselage and wings are covered with masking tape to catch the overflow when gluing
Wing and Fuselage root shown ready to epoxy	Wing was temporarily installed and checked while the fuselage is squared up. The wing root when flush to the fuselage was in the correct position	Clear epoxy is applied to the wing root and left to soak in...do not apply epoxy to the wood dowels
Epoxy is thickened with fiberglass mil and spreaded thick as shown	The forward and rear wood dowel holes are cleaned with a Q-tip	The wing is installed on the fuselage

The wing is pressed down in place and excess epoxy is cleaned with denatured alcohol and a paper towel	Make sure the wing is flush to both the root and the bottom of the fuselage. You can slide the ply squares over the wood dowels on the inside to help hold the wing to the fuselage	Remove the tape from the wing and fuselage before the glue sets
Allow some time for the epoxy to set	Once the epoxy has set but is still soft, you can check the rivots that were formed at the drill points. Use your finger to round them out and slightly flatten them for a better hold as shown	Apply epoxy to the other fuselage root and wing
Clean the wood dowel holes out as shown	The wing is installed on the fuselage	Seat the wing, clean up the excess epoxy and remove the tape as with the first wing, then allow some time for the glue to set

Both wings are shown installed	The wing seams are filled with a lightweight body filler and sanded to shape	A piece of 60 grit sandpaper is used to rough up the fuselage area for glassing. Sand about a 1" wide area from front to back
Strips of 2-5oz cloth are cut 2" wide in preparation for glassing	Epoxy is applied to the side of the fuselage and wing area	The glass cloth is placed in position and excess epoxy is removed
Wing to fuselage area shown glassed and allowed to set up	The bottom of the wing area is glassed the same way	Strips of glass cloth are applied to the area. I used 2 oz fiberglass cloth on the top for a nicer finish and 5oz cloth as shown on the bottom for strength

The bottom of the wing is shown glassed. Sand and blend the seams	The horizontal stab and elevator pieces are shown in the pic	Thin CA is applied to the leading edge of the Elevator
The Elevator is installed centered over the edge of the Stab and flush with the inside	The elevator is mounted to the second stab in the same manner	A piece of paper is taped to the vertical stab at the Elevator location and the airfoil shape is traced out as shown
The shape is cut out from the tracing	A center line is marked down the leading edge of each Flying Stab	A center line is drawn down the leading edge at the marks

Center line is drawn on the second stab as shown	The cut out pattern is used to trace the airfoil shape to each stab inner root	The sanding board is used to form the airfoil shape and taper the tail to 1/16" thick for each of the two Stabs
The leading and trailing edge has been tapered as shown	Both Stabs are aligned on top of one another and the inner rear edge is shaped to align itself with the root (top right), then the outer side is shaped with a sanding block as shown (left)	A center line is drawn down the outer edge of each stab
A ruler is used to measure 6 1/2" from the inside root	Lines are drawn as shown on each stab	A sanding block is used to taper the stab outer tips in the same way the wing tips were shaped. Sand from the line that was drawn to the tip making an even bevel

The second stab was tapered as shown	Two pieces of 3/4 oz fiberglass cloth were cut to overlap and cover both sides of each stab. Use medium CA to anchor the leading edge as shown and wipe away any excess glue while pressing the cloth down	Epoxy finishing resin is applied to the inside root, leading outer and trailing edges, then to one side of the stab. The cloth is applied and stretched to remove wrinkles
The other side of the stab is glassed in the same manner	A thin sheet of plastic is used to help seal the stab and remove the excess resin without disturbing cloth position	The plastic sheet is applied to the other side of the stab and the excess resin is removed. Once done, the plastic edges are trimmed as shown and the stab is placed in a phonebook while the resin sets
The second stab is glassed in the same manner as the first	It is shown placed in plastic. Insert into a phonebook while the resin sets	Horizontal Stabs are sanded and ready to install

Make a center line on the stabs, around 2 3/16" from the front	Make a starting divot in the center of each Stab	Center mark shown in the pic
Mark the same distance, in this case 2 3/16", from the front tip of the stab molding on the vertical fin	Make a vertical center mark	Take great care and drill dead center on the mark
The hole is opened up with a 5/32" drill bit	Install a piece of 5/32" OD brass tube through both holes and check alignment. If it is off, you may have to file the holes so both sides are the same	Seal one side of the two remaining 1/8" x 1/2" ply squares with CA

Mark punch holes in the pieces at the center for drilling	Drill a 5/32" hole in each of the two ply squares	A piece of 1/8" wire is marked and cut to 3" long
Two pieces of 5/32" brass tube are marked and cut to 1 1/4" long	The brass tube is inserted into the vertical fin area and marked to cut so it will remain flush to the sides of the fin. The two ply plates are positioned and checked for center, then tacked in place with epoxy	The piece for the fin is cut to length
The brass tube is installed and checked to make sure it is flush on each side. Sand as necessary for a good fit	Photo shows the brass tube and plates in place	The two 1 1/4" brass tubes should be roughed up on the outside with sandpaper before gluing in place

The 1/8" rod and tubes are test fit for free movement	A drill is run through the center of the fin, drilling the pivot hole in the stab. Hold the stab flush to the side of the fin and perpendicular to the fin while drilling	The Horizontal Stabs are test fit and position is checked
Check position of the Stabs from the rear to make sure they are parallel to the wings and perpendicular to the tail	With the 1/8" wire installed, make a mark 1 5/8" from the front of the wire forward to mark the front position for the actuator wire	Measure and make a mark 1/8" back from the front line you made for the area that needs cut
Use a sharp knife or cutting tool to open the area, then fin shape it with a file or small router bit	The slotted area is shown shaped and ready for installation	A piece of 1/8" brass tube is used for the actuator assembly and should appear squared up to the sides of the vertical fin as shown

Mark and cut a piece of 3/32" wire (4-40 push rod) to 2" in length	This pushrod is used as the actuator for the Elevator	A piece of 1/8" brass tube is marked and cut to a length of 1" long. Make two of these tubes