Pazmany PL-4A. Scale model for radio control. For K&B .40 power. Scale is 1/5. Planfile includes detailed build instructions.
Quote: "Contruction Sequence. Pazmany PL-4A.
WINGS: As the wing is a constant chord, you can manufacture all the ribs via the sandwich method by assembling sixteen of 1/16 and four of 1/8 balsa blanks between two 1/8 ply templates. These are cut to comply with the W2 rib shape. After shaping the ribs to the ply template you can now separate the ribs and, using the drawings, add the additional cutouts and slots to suit the total wing requirements. Note: The two ply templates used are now altered to become the two W1 ribs. Join the 1/16 sheet for the bottom wing skins. Cut out and shape the 1/4 sheet braces which are used to hold the bottom sheet to shape against the ribs. Mark out the spar and rib positions on the bottom sheet for the outer panels.
Pin the braces and bottom sheet to a flat surface, add spar, ribs, leading edge and 1/8 x 5/8 aileron spar. Add both triangular sections, shape and install the aileron leading edge, followed by the aileron ribs W6 and W7. Add the dihedral braces W13 and W14 followed by riblet W5. Mount the aileron crank in its ply base and install. When dry, set aside and repeat for the other panel.
Set out the centre wing panel in similar fashion. However, do not glue down center undercarriage assembly, consisting of ribs Wl, U/C braces W8, W10, W12 servo mount W9 and riblet W15 since these are all assembled as a separate unit with epoxy. Spar stiffener W11 is glued to the bottom of spar only at this time.
The ailerons are carefully cut out and hinged. Cut is slot in the aileron leading edge and relieve the immediate area to allow for link adjustment and epoxy aileron horn in position. Do not glue hinges in position at this time. Install aileron pushrods and terminate the pushrod about 1 in outside the outer panel. Using the dihedral jig, join the two outer panels to the center section.
With the ailerons taped in position, brace up the wing and pin one outer wing panel down on the wing bracers. Now cover the top of the wing with pre-joined 1/16 sheet. Repeat on the other panel.
Cut slots in center section panel to accept the undercarriage. Carefully place the undercarriage through the slots and bolt the assembly with 4-40 bolts and nuts. Brace up the center section and epoxy the undercarriage assembly to the wing. Now add upper brace W11. Fill the area at rear of ribs W1 with scrap so it will not compress when the wing bolts are installed.
Trial-fit the aileron servo and join the pushrod with split brass tubing. Now cover the center section with pre-joined 1/16 balsa. When this is dry, cut out the aileron servo access. Cut the top skin to release the ailerons and inset the 1 mm ply shroud. This ensures minimum clearance to allow proper aileron movement and it will not curl.
Glue on soft balsa wingtip blocks and carve them to shape. Cut off the outer curved section as per plan and hollow the inner section. Re-glue the outer section on and install the 1/16 soft wire to protect the tips. Use epoxy glue here as this not only protects the tips, it also ensures that they will not curl out of shape.
STABILIZER: Cut two 1 mm ply rib templates and, using the sandwich method once again, make eight of 1/16 and one of 1/4 soft balsa ribs. Using the 2 mm ply templates, open the spar holes to 1/4 and face the two center section 1/16 ribs around the dowel spar and after appropriate bracing up of the lower skin, glue the assembly in place. Add the 1/8 and 1/4 balsa center section fillers plus the tab spar and 1/4 square tab hinge supports. Cover the stab top with 1/16 soft balsa. When this is dry, sand it to shape and add the tips..."
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