1912 Blackburn Type D Monoplane
Build log continues on Blackburn fuselage construction
Building the Blackburn fuselage
See pictures of Alan's build of a slightly smaller version of the 1912 Blackburn monoplane here!
As your build your own Blackburn the balsa fuselage goes together easily, and is made primarily of 1/8” square balsa with some 1/16” plywood. The fuselage is built upside down directly on the plans for accurate alignment. The plywood former F-1 serves to provide a solid anchor for the Blackburn’s firewall, battery tray, wing mount tubes, servos and rear fuselage frame.
I always recommend making a “kit” of a the plans parts when building from a plan. Cut out formers F-8 thru F-18 from plywood or balsa. Note that the plans show various cutouts on the formers F-9 thru F-11, and especially F-1. Adjust these openings as required to allow for your motor, battery, servo and electronic speed controller size and arrangement.
The next step is to make the F-2 thru F-7 lower fuselage formers. These formers are made out of 1/8” square balsa with scrap 1/16” balsa for reinforcement. Do pay attention to make these lower formers as accurate as possible as per the plans. These formers set the overall shape of the lower fuselage, and provide the distinctive triangular cross section.
Fuselage top frame
Now is the time to make the fuselage top frame front and top frame rear. The two frames are built directly over the plans from 1/8” square balsa. Use a bit heavier grade of balsa for strength on the front frame and a lighter grade for the rear frame to avoid a tail heavy model.
When the two frames are complete, join them upside down directly over the top view. Note that the rear frame overlaps the top frame, thus the need to glue the rear frame on the top of the front frame while the top frame is upside down over the plans. The reason for this overlap is to allow the horizontal stabilizer to be on top of the rear fuselage frame, yet have the stabilizer (which is make from 1/8” square balsa) be level with the front top fuselage frame. Study the plans side view and this arrangement will be clear. See how you can design a plane like the Blackburn in video clips here!
Fuselage lower formers
After the front and rear fuselage frame sections are complete and glued together (still upside down over the plans), you can now glue on the fuselage formers F-2 thru F-7. You will see the result of carefully making these lower formers as the fuselage starts to take shape. Once these lower formers are in place, add the 1/8” square balsa keel. When dry, remove the fuselage assembly from the building board.
Check the fit of F-1 onto the top of the fuselage, and carefully glue F-1 in place. Ensure you have a good fit of F-1. Use 5 minute epoxy for strength, and to allow a short amount of time to adjust the exact placement of F-1 as the glue dries.
Blackburn tail surfaces
Make the horizontal and vertical tail surfaces at this time. The covered horizontal stabilizer is now needed to complete the fuselage construction. The tail surfaces are all made of 1/8” square balsa, with scrap 1/8” balsa for corner joint reinforcements. Try to use light 1/8” square balsa for the tail surfaces to avoid any tendency towards a tail heavy model. Bevel the leading edge of the elevator and rudder to allow for full control movement.
Cover the horizontal stabilizer before gluing it to the fuselage. I used Coverite CoverLite Cream for the entire Blackburn model. CoverLite is very lightweight, but needs an adhesive before ironing on. I used Sig Stix-It, and brushed the Stix-It to the area where I wanted the CoverLite to bond when ironed on. The CoverLite does not shrink as with normal iron-on coverings. But that is alright, as the Blackburn’s structure certainly cannot take much covering shrinkage and the overall effect of the CoverLite applied “as is” makes for a pleasing effect evocative of the Blackburn’s era. To save weight, I covered just the top surface of the stabilizer and elevator. I covered both sides of the vertical fin and rudder for a better look.
Upper Blackburn fuselage formers
Carefully glue on formers F-9 thru F-10 in the forward fuselage locations. Install the 1/8” square balsa at the top of F-9 thru F-10. Epoxy the triangular 1/16” plywood firewall braces F-18 to the crutch F-1.
Before you glue on additional top fuselage formers aft of the cockpit, glue the covered horizontal stabilizer onto the top of the rear fuselage frame. Take a moment to study the plans and ensure you see how the stabilizer fits onto the rear end of the fuselage, and aligns with the front fuselage frame.
Once satisfied with the placement of the stabilizer on the fuselage go ahead and glue the covered stabilizer in place. Add the remaining fuselage formers F-12 thru F-17, which are glued on top of the newly installed stabilizer. Cut away the stabilizer covering to ensure a wood-to-wood glue joint for these formers. Install the top 1/8” square balsa stringer from F-12 to the stabilizer as depicted on the RC airplane plans, and then the 1/16” square balsa stringers from F-13 to the rear of the fuselage.
Author: Gordon McKay