Vendors Corner > Mikey's models
P-Force XL wing build
MikeyPratt:
Carbon Fiber Pushrod,
Begins by purchasing the a 36 pushrod kit from Central Hobbies and the Titanium 4-40 inserts. Very high quality products and well represented by many model builders they are great products. I like them because the are light and very stiff (they do not need a pushrod support) and easy to assemble.
Trim the the C/F pushrod to a length of 22 (wrap the pushrod with masking tale where you are going to trim off the C/F pushrod) the help prevent from splitting carbon shaft when cutting it off. Sand the both ends with 220 grit sandpaper 1 back from the end to roughen the each end each of the pushrod. Stick the end of the C/F tube into isopropyl alcohol and let it stand for a few minutes, this removes any residue of and molding release wax for a better bond between the C/F pushrod and titanium insert, and wipe off the insert as well. Mix up a good amount of JB Weld and throughly mix the two halves of epoxy. Apply the JB Weld into the end of the C/F tube with a toothpick reaching into the tube at least 1, next apply JB Weld to titanium insert limberly on the end of the connector and install the connector into the tube. Wipe off any epoxy that oozed out of the pushrod with a paper towel with isopropyl ilcohol. Stand the push rod vertically and allow the epoxy to harden slightly. Replete this process to attach the other titanium connector. Allow the pushrod to set 24 hours to fully cure before use..
Wrap the ends of the pushrod and the last part of the connector to strengthen the ends with heavy weight thread and thin CA glue and allow to dry. Install a 4-40 nylon ball link to each end threading the ball link onto the connector at least 1/2. This is where people twist the ball link on too far onto the connector and that binds the ball on the plastic end of the ball link. If the ball link is too tight at the beginning, Dont use it and replace it with a new one that moves freely. Note: In the past, Ive crimped the ball- joint with pair of pliers to free the ball within the plastic end, it helped at first but in time it became stiff again and had to open up the wing sheeting and replace the ball-link.
MikeyPratt:
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.
The bell-crank and least-outs can now be installed in the wing. The bell-cranks is supported by 1/8 music wire (or optional 1/8 drill rod) through the plywood bell-crank supports. Make a bell-crank support 1/8 rod thats 2-1/2 long. At one end of the rod cut a grove with your Dremel cut-off wheel, 1/16 from the end of the rod, slip a piece of silicone fuel tubing over the support rod and stand vertically in a vise or locking pliers, place a number two flat washer on the top of the support rod (make sure you have sanded the rod and washer to get a great solder joint), solder the #2 washer to the top of the support rod allowing the solder flow around and into the grove of the support rod to really lock and hold it in place. Clean off the support rod by brushing off the flux and residue with Lacquer or dope thinner. The bell-crank support rod can be slipped in place capturing the B/C in place along with the 1/8 i.d. x 1 Brass eyelets, Note: The large flared flat end of the eyelet goes agonist each side of the bell-crank The bell-crank assembly should be centered between the spars with almost zero slop in the movement of the crank assembly up or down or side to side. Both of my models required 1/32 plywood washers at the end of the brass eyelets and the bell-crank mounts.
Once satisfied with the centering of the B/C, solder a #2 flat washer on the opposite end of the B/C support rod using the same procedure that was mentioned previously.
Attach the CF pushrod to the bell-crank using a 4-40 socket head bolt in the inside hole of the BC. Make sure the bolt head doesnt rub on the wing spars. In the ball link package, your provided a tapered stand off. I found the stand off to be much too thick, so I sanded and filed the excess away (about .030) to get a the clearance I wanted. Install the push rod assembly by installing the 4-40 socket head bolt, flat washer through the ball link, bell crank and tighten in place. Thread a 4-40 nylon lock nut to the back side of the bell crank and cut off any excess bolt flush with the nut. Place a drop of epoxy to the nut & bolt to lock them in place.
MikeyPratt:
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 outer 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 inner 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, use Tite Bond glue to glue the trailing edge in place. Pin in place and allow to dry. Using a CA glue seems to cause a ripple affect on the trailing edge between the ribs. Thats why I like the Tite Bond better.
MikeyPratt:
Finish the lead-outs by cutting two lengths of 1/4 heat shrink tubing that are 1-1/4 in length, slip one piece of the heat-shrink tubing over the .027 cable to the bell-crank lead-out attachment and slider the heat-shrink tubing over the copper wire wrapping. Using a heat gun, shrink the tubing in place to prevent the copper wire from unwrapping. Allow it to cool. Using the same procedure do the reaming lead-out cable.
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