From here on the notes are numbered to correspond to the step in the instructions under discussion. In some cases they are just notes on the step. In other cases they are a complete rewrite of the step. Please be sure to review the original instructions along with these notes.

2. I don’t understand the last sentence of this step. The doubler is not 1/4” short of the bottom and it does not touch the 1/4” triangular stringer. Don’t worry, just ignore this and glue the doubler in place. Be careful in the placement of the doublers as they will guide the placement of bulkheads #2 and #3 in the next step. Accurate placement of bulkhead #2 is very important.

3. Make sure you have cut all necessary holes in the bulkheads. On bulkhead #2, I prefer to wait to drill the wing dowel holes until step 8 of Completing The Wing so they match exactly with the leading edge.

I draw the centerline on both the front and back of Bulkhead #2.

Paragraph 2, draw the center line down the length of all three top blocks. Draw a line across the fuel tank compartment top block at the location of the aft end of the engine compartment top block. Draw a line across the top block at the location of the cross brace in the servo compartment, at bulkhead #3 and at the location of the cross brace to the rear of bulkhead.

Paragraph 3, I do not find the lines on the fuselage sides to mark the location of bulkheads #2 and #3 to be necessary as the bulkheads fit flush against the doubler.

The last paragraph of step 3 is a common source of confusion. The top block cross braces are no longer factory cut to size. They are now provided as 1/4" x 3/8” x 24” balsa stock. I did not cut these at this point and I didn’t mark them at all. They will be cut to fit in later steps.

4. I find fitting an engine to a built fuselage and then drilling motor mount holes accurately to be difficult and prefer to prepare the firewall for the engine mount before assembly. So in step 4 I drilled the holes listed but I also drilled the holes for the engine mount blind nuts and mounted the blind nuts in the firewall.

5. The second paragraph should read Relieve the 3/8” balsa engine compartment as necessary for your fuel tank. See the plans.

The last line should read Use the line you drew across the fuel tank compartment top block earlier to locate the engine compartment top block.

6. Due to the cross braces not being pre-cut, I find it easier to get them sized accurately and mounted later. I skip this step and install these pieces at the end of step 7.

7. The 3/8” triangle stringers used in this step are not standard triangle stock. They are triangle stock with one corner cut off. As stated in the instructions, the stringers should be glued to the fuse sides with the cut off edge uppermost.

Now is when I cut and fit the fuselage top cross braces from the 1/4” x 3/8” stock. One where marked in the area of the servo compartment, one where in the position of bulkhead #3 (the bulkhead will be glued on top of the cross brace) and one aft of bulkhead #3.

10. The vertical support braces in this step are also cut from the 1/4” x 3/8” stock.

12. The plans show the 1/4” triangle stock on the front of bulkhead #2, not the back.

15. The balsa triangle stock is actually 1/2” x 1/2", not 5/8”. On my first Dirty Birdy I had a problem when gluing these pieces to the top block. This time I cut the pieces to fit but installed bulkhead 1 before installing the triangles. I believe it was much more accurate.

17. The instructions say to use a square to make an alignment template for bulkhead #1 but the bulkhead needs to be angled for 2 degrees down thrust. So you actually need a 92 degree template, not a 90 degree template. Using a protractor, mark a 92 degree line across a sheet of 1/8” balsa. Mark this corner on the template so you can distinguish it later. Cut the template with an X-Acto and a straight edge.

18. If you waited to install the triangle stock as I did, use care when you epoxy bulkhead # 1 to the fuel tank compartment block. Make sure you do not ooze glue into the area where the triangle stock will go.

19. At this point I epoxy in the triangle stock as well as pulling in the sides and gluing them to bulkhead #1 and the top block.

20. These parts have changed. There aren’t really any fuel tank compartment side blocks with notches cut into them. They are roughly triangular pieces made from 3/16” sheet. Check the parts list. If you have moved bulkhead #1 from the location shown in the plans, you will need to trim these parts accordingly.

Add triangle stock to the back of Bulkhead #1

Add triangle stock to the bottom of the tank compartment bottom sides.

22. The nose gear bearing is now integral to the engine mount. Install the engine mount. At this point I discovered that with my engine, the provided adjustable motor mount would not fit in the engine compartment, it was a little to wide at the front end. So I narrowed the front of the mount on a disk sander to the same width as the engine’s mounting lugs. It was now a perfect fit.