Toolboxes Done! On to the Real Thing!
A. Carefully study mechanical drawing and identify top part and bottom part as shown. Note the orientation of the parts and their relative placement.
A. Deburr the edges of the top and bottom plates per section 5.2 of the Van's Construction drawings using deburr tool and Scotchbrite pad.
B. Consider when to remove the plastic protective film from the plates. Consider what areas may need primer before assembly.
A. Layout rivet pattern on top plate. Maintain 1/2" edge distance and evenly space rivet holes accordingly.
B. Align top plate to bottom plate and mark final location to evenly space the top plate on the bottom plate per note #3.
A. Using a #40 drill bit, drill rivet holes in the top plate at all locations.
B. Align top plate to previously marked location on the bottom plate and clamp.
C. Drill and cleco top plate to bottom plate.
D. Using a #30 drill bit, enlarge the holes for the LP4-3 pulled rivets.
E. Disassemble top and bottom plate and deburr all rivet holes.
F. Determine suitability of material for Machine countersink riveting.
G. If appropriate, Machine countersink bottom plate for AN426 flush rivets per mechanical drawing note #1.
H. Dimple both top and bottom plates for AN426 flush rivets per mechanical drawing note #2. Flush head should be on the bottom of the assembly.
A. Cleco top and bottom plate together using both 3/32 and 1/8 inch clecos.
B. Using a rivet squeezer and flat rivet sets, install AN426AD3-3.5 rivets in previously dimpled center row of rivet holes. (5.5).
C. Remove clecos and insert AN429AD3-3.5 rivets in previously machine countersunk holes and hold in place with rivet tape.
D. Using a pneumatic rivet gun, back rivet plate and back rivet set, drive all five rivets. (5.6).
E. Using a pneumatic rivet puller, install five LP4-3 pulled rivets with the rivet head again on the bottom of the assembly. (5.5).
A. Inspect all rivets according to Van's construction drawings sections 5.2 to 5.6.
The next project the students undertook on 3/5/17 is a "Practice Kit" sold by Van's Aircraft. It further teaches the students the necessary skills to build an aluminum aircraft like the RV-12. When finished, the students have a toolbox for their keeping.
Prior to actually working on the real airplane, new skills need to be learned by the students. The first was a clever exercise that Mel Jordan worked up. It involved using two pieces of aluminum using instructions that mimic the actual Van's Aircraft builder plans. They were realistic and showed the students (and a couple of us mentors) that by not studying the plans fully, errors could occur.
Aircraft Building Exercise #1 - Sheet metal riveting
1. Understanding Mechanical Drawings
2. Preparing metal parts
a. Edge finishing
3. Layout of rivet patterns
4.Rivet Hole Preparation
5. Rivet Setting Operations
b. Back Riveting
c. Pneumatic Pulling
Mr. Jordan's kit above and finished.