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© 2005 - Bernard Burton                                                                                DRAFT 

9

Bottom wings: 

Step 1

:  1) Prepare upper left wing: 

-  On a flat workbench, prepare & protect your plan.  
-  Pin the lower main spar on the plan 
-  Glue all the wing ribs on the lower main spar (Hard wood 10x10 mm) according the 

plan.  W1B-W2B-W3B-W9 should be glued with 30’ epoxy. Other ribs can be glued 
with polyurethane glue. Pin the rear rib alignment  tabs on the workbench to 
guarantee a straight wing trailing edge 

-  Proceed with the upper main spar (Hard wood 10x10 mm) as well as with the top 5x5 

mm balsa spars  

-  Glue the 10x10 mm Balsa leading edge and the balsa trailing edge 
-  Proceed with all remaining 5x5 mm balsa spars (upper & lower) 
-  To prevent wing torsion,  glue 2 mm balsa re-enforcement  between the upper and 

lower main spars (vertical fiber direction) 

-  Cover the wing with 2 mm balsa sheet according the plan 
-  Glue the rib caps 

 
 

 

 
-  Prepare the servo support assembly and glue it in place.  Consider that the servo arm 

is on the lower side of the wing 

-  Install the optional wing tip if required. Use the small balsa square triangles to re-

enforce the wing tip fixation. 

-  Prepare the aileron: pin a 2mm balsa sheet according the plan. Glue the aileron ribs 

(small & long triangles). Re-enforce at the position of the control horn. Put the leading 
edge spars (square & triangle) and cover the top with a 2 mm balsa sheet. 

-  Glue W9a plywood ribs on W9 with 30’ epoxy. The tabs should be placed on the 

upper side of the wing 

-  Put a wire in the wing to ease the servo wires installation at a later stage. 
-  When the glue is fully cured, remove the wing & aileron from the workbench 
-  Remove the rib alignment tabs except the W1b & W9 alignment tabs. 
-  Continue to cover the wing with 2 mm balsa sheet according the plan but ensure that 

you can still access W1-W2-W3-W5 ribs to glue the wing tubes at a later stage. 

 

Step 2

:  Prepare bottom right wing following the same instructions as here above. 

 

Step 3

:  When the right & left bottom wings are ready, proceed as follow: 

-  On a flat workbench, align the wings and glue the right & left half wing tube sockets in 

place with the aluminum tube inside. Do not glue the aluminum tube in their sockets. 
Note: a dry assembly could be required to ensure a perfect alignment before gluing.   

-  Verify and eventually adjust the alignments before the glue cures 
-  Remove the remaining alignment tabs. 
-  Close the right & left wings with the remaining 2mm balsa sheeting 
-  Glue the remaining rib caps 
-  At this stage, the wings alignment should be perfect: straight & not twisted. The four 

tabs (wing fixations) should rest on the workbench without any constrains. 

-  Sand the leading edges. 
-  Your bottom wing is ready.  

Note:  

During the previous steps, always verify and eventually adjust the 

alignments before the glue cures. 

Summary of Contents for Spirit of Pitts

Page 1: ... 2005 Bernard Burton DRAFT 1 Designed in 2005 by Bernard Burton Assembly manual ...

Page 2: ...ed to tell you how to build this aircraft each builder has their own approach to building This is only a guide which will show you how we built our Spirit of Pitts Use it if you feel that it may help NOT ALL STEPS ARE SHOWN IN THIS MANUAL Disclaimer This plane and plans are intended for ADVANCED BUILDERS and PILOTS ONLY The user shall determine the suitability of the product for their intended use...

Page 3: ... cure Î Step 3 Build crutch assembly upside down on a flat workbench We can not emphasize enough the importance of building this crutch square and also the alignment to the print This is as important as building a straight wing The flat surface of the formers should be placed on the workbench Glue with 30 epoxy the formers F5 F2 F2 doubled F3 and F4 on their respective places on the fuse sides S1 ...

Page 4: ...5 Glue the S1 doublers between F1 F2 and between F2 and F3 on the outsides of F1 This is to re enforce the position where the wing struts are attached Step 6 Glue F6 F7 F8 and F9 in place Verify and eventually adjust the alignments and let the epoxy cure Step 7 Join the formers with balsa sticks Helpful hint Use a piece of scrap foam or balsa to hold the fuse sides out against the formers while yo...

Page 5: ...four 5x5 mm Balsa stick on the former slots bottom half from F2 up to F2 Step 8 Prepare the removable canopy Put the canopy formers FT1 FT2 FT3 FT4 and F6a on their place according the plans on the fuse Do not glue the formers on the fuse Glue the 5x5 mm 10x10 mm balsa sticks on the formers according the plan Pay attention that the lower 10x10 mm stick is going up to F6a Do not glue the stick on t...

Page 6: ...asy sheet wrapping around the fuse you can spread an Ammoniac Water mixture on the balsa sheet Wrap the wet sheet in place and let it dry for a night Use CA glue to glue the balsa sheets according the plan drawings with special care for the wing join Step 12 Elevator and rudder assembly On a flat workbench build the elevator and rudder panels using a copy of the plans Use polyurethane glue for max...

Page 7: ...s and let the epoxy cure Glue all the 5x5 mm sticks between the three CF rings Verify and eventually adjust the alignments and let the epoxy cure Wrap the cowl with 2mm balsa sheet Glue with 30 epoxy Sand the concentric rings on the outside to have a smooth curved cowl noose Wait until the motor is installed before adjusting fixing the cowl on the fuse Helpful hint The length of the cowl should yo...

Page 8: ...balsa sheet Put a wire in the wing to ease the servo wires installation at a later stage When the glue is fully cured remove the wing aileron from the workbench Glue W9a W9b plywood ribs on W3 W9 with 30 epoxy The tabs should be placed on the lower side of the wing Remove the rib alignment tabs Except the W1 W9 alignment tabs If your job is well done the wing should rest on the four wing fixation ...

Page 9: ...ge spars square triangle and cover the top with a 2 mm balsa sheet Glue W9a plywood ribs on W9 with 30 epoxy The tabs should be placed on the upper side of the wing Put a wire in the wing to ease the servo wires installation at a later stage When the glue is fully cured remove the wing aileron from the workbench Remove the rib alignment tabs except the W1b W9 alignment tabs Continue to cover the w...

Page 10: ...udder assembly with the bottom wing o The distance between the trailing wing tip and the trailing elevator tip must be the symmetric for left and right o The wing horizontal axis must be parallel with the elevator horizontal axis o The elevator incidence compared to the fuse axis 0 o Glue the elevator rudder assembly with 30 epoxy o Verify and eventually adjust again the alignments before the glue...

Page 11: ... Bernard Burton DRAFT 11 Center of Gravity The plane should be centered at 25 of the median chord or 147 mm from the leading edge of the top wing The Center of Gravity can be moved backward for 3D acrobatics ...

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