Vendors Corner > Mikey's models
P-Force XL wing build
MikeyPratt:
Right Wing:
Built the right wing panel in the same manner as the left wing panel as shown in the previous steps. Laminate the right W-1 wing rib to the left W-1 wing rib. Block up the lower wing spars with the balsa scraps, add the remainder of the wing ribs making sure they are positioned and securely pined in place. Note: The wing will not be unpinned from the building board until after the trailing edge and some of the center section sheeting is finished.
Install thse inner 1/8 X 1 X 30 balsa leading edges on both the left and right wing panels and glue in place with thin CA glue (the leading edge will be finished after the leading edge sheeting is installed). Place a length of making tape on top of the wing ribs behind the inner leading edge. This helps protect the top of the ribs during carving and sanding the leading edge to shape. Trim and sand the inner leading edge down to the top of the ribs. Do not sand through the masking tape. Replete this step for the top of the left wing panel.
Make up two full length trailing edges (Note: The trailing edges are joined together with a long scarf between the W-2 wing ribs as shown on the plan). Remnember the trailing edge scarf joints are opposite from each other between the W-2 wing ribs when assembled. Using a long straight edge make sure the trailing edge is straight and fits snuggly up to the wing rib alignment tabs on each wing rib before gluing in place.
Install the laser cut plywood bell-crank mounts (upper & lower) with thick CA glue. Make sure the the bell-crank pivot holes are aligned by passing a 1/8 music wire pin through the plywood mounts, making sure the music wire pin is vertical before gluing in place. Add a 1/2 X 1/2 triangle stock to each end of the plywood bell-crank mounts for additional reinforcement.
BELL-CRANK
This is a good time to talk about bell-cranks and lead-outs. My preference is the Sig 4 bell crank mainly because I like the way it handles the model with its positive feel and 4 length gives it good power for flight loads without being overly sensitive. Below are a few suggestions to improve the installation and make sure there is no slop in the controls at neutral.
Drill out the center hole of the plastic bushings with a 3/16 drill bit to install a 1/8 i.d. Brass bushing. The brass bushing should be a tight fit into the plastic bushing. Place bushing into the bell-crank so the bushing sits on top of the raised bearing surface on the bell crank. Using a long sanding block sand the B/C bushing and tubing until its flush & flat with the bottom of the B/C. Flip the bushing over and reinstall the plastic bushing, it should be flush with the raised side of the B/C. At the outer ends of the B/C, enlarge these hole fron .0625 (1/16) to .045 dia so there is room for the lead-out bushings to move freely when the controls are activated.
Tap the inner hole only of the bell-crack output arm with a 4-40 tap to install the ball-link at a later times during construction. Note: The outer hole of the output arm of the bell crank will be used after assembly to set the controls at precisely neutral. In each of the bell-crank plywood mounts there are two holes, the B/C pivot hole is 1/8 d.i. And the neutral alignment hole is 1/16 dia, after the bell-crank is assembled into the wing, place a 1/16 wire or drill bit by passing the 1/16 wire through the plywood B/C mounts and bell-crank to hold the B/C in the neutral position. With the B/C held in the neutral position you can wrap the end of the lead-outs after the adjustable lead out guide and wing tips are installed on the wing assembly. You will find that this is a really handy way to adjust the neutral of your model.
MikeyPratt:
Begin by cutting twp lengths of 1/16 O.D. Brass or Copper tubing 2-1/2 inches long, (Note; if using hard brass you must remove the temper from the brass by heating each length of tubing until it has light red in color, then allow the tubing to cool), Next, cut two .027 X 36 stainless cables, slip one of the brass tubes over the .027 cables with about 2 of cable past the brass tubing. Using a pin vise of about 1/4 dia. place the middle of the brass tubing over the pin vise and bend the brass around the pin vise. Bend the brass tubing equally over the pin vise until you have two equal lengths of tubing.
MikeyPratt:
Next, slip the newly formed bushing into the B/C making sure the bend in the bushing is centered. (Note; you can make slight adjustments to the length of the bushing at this point). Gently push the ends of the L/O bushings together making sure they are both equal in length. Also make sure the .027 cable is at least 2 long, before wrapping the end of the B/C end, this will be folding over against the coils before wrapping the second round of coils at the B/C end. Now we can add our fist set of copper coils to the wrapping. Start by wrapping our copper wire around the two lengths of cable with 1/2 extra copper wire inside the brass bushing. Keep the coils touching each other and tight as possible and finish wrapping the coil around the cables until the the wrap of coils is at least 3/4. Using a small set of needle nose players, you can grasp the cables and tighten the coil with your thumb nail by pushing the coil towards the B/C Just make sure you dont kink the cables doing this. Note: (For reference, you can look closely at the attached photo you can see a finished lead-out cable attached to the bell-crank).
MikeyPratt:
Now we can add our fist set of copper coils to the wrapping. Start by wrapping our copper wire around the two lengths of cable with 1/2 extra copper wire inside the brass bushing. Keep the copper wire wraps touching each other and tight as you can and finish wrapping the copper wire around the cables until the the wrap is at least 3/4. Using a small set of needle nose players, you can grasp the cable and tighten the coil with your thumb nail by pushing the coil towards the B/C Just make sure you dont kink the cables doing this.
MikeyPratt:
Continue wrapping the copper wire for a length of 3/4 of and inch making sure all the wrappings are tight and touching the previous coils. One again, if needed, slide the coils together with you thumb nail. Next, bend over the excess of the cable and slightly crimp the the end of the cable so it fits flush on top of the copper wire coil, (make sure you are crimping the excess cable and not the lead-out). Trim off the excess cable close to the end of the brass bell-crank bushing, Next step, finish wrapping the second coil of copper wire on top of the previous coil, to securely lock the cable in place. Continue wrapping this coil until you reach the end of the bell-crank bushing. Tie off the end of the copper wire by twisting the two copper wires together. Cut off the excess and bend the twisted wire into the end of the bell-crank bushing.
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