The Wing Panels

Paragraph 3 of the wing panel instructions describe drawing lines on the ribs. This doesn’t work with the current ribs as they have notches in the front and aft ends. More on how I used these notches later.

Paragraph 4 of the wing instructions says that ribs #3 and #4 are notched but that is no longer the case so be sure to notch them for your desired gear position. Note that on the plans the notches are not as deep as the landing gear block. The block actually stands above the ribs by the thickness of the sheeting so the block winds up flush with the sheeting. On my first DB, I made a mistake and cut the notches to make the block flush with the rib so I just sheeted over it. I wound up liking this much better because I’ve always had trouble fitting the sheeting neatly around the blocks. Of course if you sheet over the blocks, you’ll have to carve away the sheeting where the LG straps go so they don’t crush the sheeting. To do this neatly, drill and install the gear straps. Then use an X-acto to cut the sheeting around the straps. Remove the straps and cleanly remove the little half moons of sheeting. If needed, add a little patch on the inside. When you cover, just MonoKote right over the depression and ignore it. When you mount the straps they will pull in and everything will be very neat.

I like my planes a little tail heavy and my first DB liked to sit on its tail when the tank was empty so I moved my gear back about 1/4" on this one. If you plan to use individual aileron servos in the wing panels, plan their location and provide holes through the ribs for the servo wires.

I understand the wing ribs in the newer kits have holes for a wing jig. I didn’t have the newer kit and I don’t have a wing jig. The instructions detail how to build the wing without a jig but I decided to build a jig on my building board. My jig consisted of balsa strips that fit in the slots in the front and back of the ribs and blocks to hold the strips off the building board. The jig was more work but was very solid and accurate. These instructions are for my method of building the wing. If you don’t want to build the jig, just follow the original instructions. But be sure to read the original instructions if you follow my method too. The steps marked with an asterisk are applicable to both methods.

To make the jig, cut four 3/8” strips from hard 1/16” balsa. Make these at least 1” longer than the wing, you want them to extend beyond the outside ribs. Make a pile of 26 - 1” x 1” x 1/2" blocks from 1” x 1” balsa. Pin the balsa blocks to the plans between the ribs about 1/8” inside the position of the leading and trailing edges plus one just outside of the first and last rib. Make sure the blocks do not touch the line on the plans for the LE or the TE or they will block the LE and TE. Look closely at the included picture. I build on a very flat hollow core door and hammered the T pins into the table. It was lots of trouble and lots of bent pins but it worked very well. The picture of the jig, spars and ribs tells the story. Note that this picture is before the LE and TE are added.

1. Pin the root end of the spar to the plans. Pin a couple of balsa blocks on either side of the spar in the outermost rib bay but don’t pin the spar itself, just capture it in place so you can lift the tip of the spar while the blocks keep it lined up with the plans. Again, look closely at the picture

2. Put the ribs in place on the bottom spar. Be sure ribs 3 and 4 have the LG notches down. (On the second wing panel ribs 3 and 4 must have the notches up.)

Slide the strip of hard 1/16” balsa into the front and back slots of the ribs, lifting the ribs so the strips will sit on top of the 1” blocks. These strips are only for positioning the height of the wing, they do not need to be glued to the LE or TE so seat them deeply into the slots. Make sure the strip extends beyond both end ribs to sit on the jig blocks on the outside of the first and last ribs.

Pin the hard balsa strips to the jig blocks. Make sure the strips do not extend beyond the front or the back of the ribs. Check the position of the ribs and square them to the table.

Add the top spar and be sure to set the spars completely into their notches. Realign the ribs. This is where the picture was taken.

CA the ribs to the spars making sure the spars are fully seated in the notches. Do not glue rib 1 to the spars! Use a square to line up the front and back of the ribs and tack glue them to the hard balsa strips. Do not get glue on the jig blocks.

3. Add the trailing edge. Glue only to the ribs, not to the hard balsa strips. Doing so will risk gluing the wing to the jig blocks

4. I shape the TE later

5. I do the sheeting later

6. I did the top spar earlier

7. Add the leading edge. I had one LE that was warped but since the ribs were jigged into their proper position I just glued the LE on making sure that it covered the tips of the ribs, not worrying if it was centered on the ribs. This problem was then fixed when the LE was trimmed in the next step.

*8. Very carefully use a razor plane to shape the top of the trailing edge to the wing contour. Don’t go too far and don’t damage the ribs. Finish this job with the long sanding block. I use a piece of paper between the sandpaper and the ribs to prevent damaging the ribs. Tape works well too

Again, carefully use a razor plane to shape the top of the leading edge to the wing contour. Be careful not to damage the rib profiles and finish with the sanding block.

On the second wing panel, after this step I removed the wing from the jig, flipped it over and remounted it to the jig. I only had to move a couple of the blocks to make things fit. Then repeat step 8, shaping the LE and TE. Flipping the wing allowed it to fit the jig better while shaping the LE and TE and sheeting the top.

9. Remove all the pins holding the aft hard balsa strip to the blocks except for the pins that are outside of the end ribs. Lay something down on top of the structure to weight it down onto the jig blocks. Add the 3/32” x 2” TRAILING EDGE SHEETING. Do not glue the sheeting to rib #1. . Put a few pins through the sheeting, the hard balsa strip and into the jig blocks to hold everything in alignment with the jig.

Remove all the pins holding the forward hard balsa strip to the jig blocks except for the pins that are outside of the end ribs. Make sure the wing is weighted down to the jig blocks. Add the 3/32” x 4” balsa TOP LEADING EDGE SHEETING. Do not glue the sheeting to rib #1.

Now we’re back in sync. Follow the original instructions with the following notes.

*12. Remember to set the LG blocks 3/32” higher than the rib surface if you’re building per the plans.

If you’re going to sheet over the LG blocks as I did, the blocks will be flush with the ribs, so you’ll have to cut the notch in the PLY PLATES 3/32” deeper.

17. When I turned the wing over, I was able to use the jig blocks again.

*Add hinge glue blocks. Cut the hard balsa strip away as necessary.

*19. Do not glue bottom TRAILING EDGE SHEETING to rib #1. Do not add bottom cap strips now. They will be done after the bottom leading edge sheeting is applied.