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 "Cloudster" Construction Project Session #28

Speed 400 Cloudster Project
The final versions of the Cloudster's wing rib and tip pattern drawings were completed as shown below. It was discovered that it was better to develop the four outboard wing rib patterns from the main rib pattern rather than generating the smaller actual airfoils with shorter chords in the Airfoil 8 programs.
A copy of the patterns were printed off and the originals were saved and filed in case more were needed for some unforeseen reason. The neat thing about the SamSung laser printer is that it faithfully copies the original patterns with absolutely no shrinkage or distortion what so ever. The outside contour of the patterns were then cut out of the copy as shown below. 
The wing tip pieces were cut out of 3/16" balsa sheet. The tip patterns are placed on the balsa sheet and the outline traced as well as possible. This always leaves a little bit to be desired. So once part of the tip piece is cut out, the pattern is placed back on the piece to check for accuracy as shown below. 
By being patient and taking your time, you can cut the two sets of wing tip pieces out with surprising accuracy as shown below.
Since the four outboard wing rib patterns were developed from the main rib pattern, a plywood template is made of the R1 rib and all of the ribs cut out using the plywood template. Then the four outboard wing ribs will be made by modifying the R1 ribs already cut out, which insures absolute spar notch spanwise alignment. To make the R1 template, the outer contour of the R1 rib pattern is cut out first. The pattern has to be bonded to a piece of 1/32" plywood. A good contact cement used for this purpose is 3M's Super 77 Spray Adhesive shown below. 
The R1 pattern and a piece of plywood are placed on a sheet of news paper and sprayed with the Super 77 Spray Adhesive. Let this set for about 3 minutes and then carefully remove the plywood from the news paper and place it on a piece of wax paper, sticky side up. Then remove the rib pattern from the news paper and carefully place it sticky side down, centered on the plywood. Fold the wax paper over and place weights on the top as shown below. The weights act as a press to insure that the R1 pattern is firmly pressed out onto the 1/32" plywood.
This is allowed to set for about 2 hours and then the wax paper is removed. The untrimmed R1 template shown below was placed on the work table and allowed to dry overnight as the adhesive is still sticky around the untrimmed edges of the plywood. Notice the two arrows pointing to the alignment holes that will be used to hold the template on the 1/16" balsa while the ribs are being cut out. These holes will be drilled out with a No. 44 drill bit so that a piece of 1/16" dowel can be inserted for pins.   
The next step will be to cut out the R1 rib plywood template. This will include drilling the two alignment holes and carefully cutting out all of the spar notches and checking their fit with actual spar stock..............................Tandy 

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