NOTE: This stage will be assembled in 2 parts.
1. Install 3 oz. lead weight in capsule, filling air gaps with modelers clay and glue base to capsule. Set aside.
2. Assemble the third stage base reduction portion and wraps per instructions but leave the bottom open for the engine mount to come later.
3. Cut 1, 18mm engine mount tube 4" long. Using an 18mm engine casing, install engine block so that it leaves 1/4" of 18mm engine protruding from bottom. Withdraw casing and glue engine block in place.
4a. Cut 1, bt-60 tube 7.5" long. Make 2 centering rings from balsa or heavy card stock, to custom fit 18mm engine casing into bt-60 tube. Make 2 centering rings from balsa or card stock to custom fit bt-60 to the lower reduction portion of the 3rd stage main body tube.
4b. Install bt 60 engine mount in to the lower reduction portion of the 3rd stage main bt, flush with the bottom of 3rd stage and cement. Allow to set. The 3rd stage engine should seat on top engine block of the center tube of 2nd stage.
5. Recovery: Install 1, 18" parachute inside of bt-60 tube.
6. Assemble 3rd stage LM/SM portion completely per instructions step # 5 and install capsule on top. The LEM portion should seat on top of the bt-60.
Reinforce bottom of LM/SM portion of 3rd stage with 1/8th balsa strips and install 2 eye screws on opposite sides and cement with CA or yellow glue for extra strength. The 18" chute will fold nicely into the top of the bt-60 tube for recovery.
NOTE: Do not glue LM/SM base portion of third stage, to the LEM upper portion. These 2 sections form the third stage but are to be stacked, not glued, just like the 1st and 2nd stages, so that they may separate for recovery. The third stage recovers in 2 pieces but on the same chute. Also, you will want to skip step 16 of the Estes instructions.
7. Same as with the 2nd stage, draw and cut 4 fins from 1/8th balsa sheet measuring: root edge 1.5", base 1.25" extending out from side of bt. Edge of fin 0.5" Slope from top to bottom is 1.5".
8. Beginning at the bottom of 3rd stage reduction wrap, mark 4 equal distant places and extend a pencil line upward 1.5". Cut a slit 1/8" wide along the line down to the bt, but not through it. Again, the idea here is to glue the fin directly to the 3rd stage bt, using the 3rd stage bottom reduction wrap as a shoulder to brace and hold the fins. Make sure the fins are aligned exactly with the 1st and 2nd stage fins, as though they are stacked.
9. Attach a 14" length of shock cord through both eye screws and connect to chute of LM/SM portion of 3rd stage. 10. Install wraps, RCS nozzles and tunnels per instructions. Escape tower optional.
NOTE: Third stage uses 1, B4-2 engine. Completed and fully prepped weighs 7.8 oz.
TOTAL WEIGHT: 26.70 ozs.
TOTAL THRUST: 18.65 lbs. or 51.87% of a G motor
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