India's GSLV Mk III -D2 Scale 1/71 Build

[Raptor 2]

Next up in my scale builds I'll be attempting the titled build using AMX Paper Space model for the wraps and scaling. This will be a challenge as the bottom end of the sustainer has a complex shape, an elongated and flattened circle which transitions into a boat tail cone supporting two engine cones. I'll be using the AMX drawings scaled up by printing at 135.5% for the wraps and the lower end of the sustainer. The main sustainer will be a BT-70, the PLF a BT-80 with extra cardstock wraps to increase the diameter to 70mm and the side boosters will be BT-60 with extra wraps to increase the diameter to 45mm. I'll start at the bottom end of the sustainer as that is the most difficult section to build. It will house a 24mm engine mount tube. The interior of the boat tail transition was lined with an extra layer of cardstock for added strength. Wraps were applied to the two side tube sections which were glued to the engine mount tube and the flat transitions wraps were held in place with elastic bands. Final cardstock transitions were then glued in place from the top end of the two side tubes to the boat tail cone. CA glue was used for the centering rings and canopy glue was used for all the transitions. A removable two engine nozzle plate will be made for display purposes.

 

[Raptor 2]

Worked on the PLF yesterday. Based on a BT-80 tube. I had to increase the diameter to 70mm from 66mm. I did this by adding 5 separate wraps of orange (any color will work) cardstock purchased at Dollarama. With the grain of the cardstock running parallel to the axis of the tube it forms to the body of the tube easier. Each wrap is applied using 3M double sided tape. The final wrap is 28Lb paper. This definitely increases the weight of the PLF but it's at the top end where I want. To help support the tube during application of the separate wraps I install a temporary pressure fit bulkhead at each end. For short tubes I stand the tube upright on a flat surface and bring the the center of a pre-curled wrap against the body tube. the center 1/2 inch of the wrap has no tape applied to it. I then apply pressure to one side near the center till it grips, then turn the tube on it's side and roll one side onto the tube. Then the other side. A temporary b/w paper wrap is printed out and used to make sure the diameter is correct.

 

[Raptor 2]

Installed two centering rings inside the PLF for the upper section of the BT-70 tube. Installed the coupler with the eye screw for the parachute in the BT-70 tube. The backside of the eye screw centering ring has 1/8" plywood backer glued in place for the eye loop to screw into. BT-70 is glued into the PLF using epoxy. The lower transition is constructed of cardstock and double layered for strength using canopy glue. A BT-20 runs thru the center of the entire front section to center the coupler and the nose cone transitions. A smaller tube will be constructed to slide inside the BT-20 to act as a plunger to hole nose cone wt if required at the top just below the top of the model.

 

[Raptor 2]

Constructed the ejection baffle. Coated the interior with CA glue. Added two interior cereal board wraps to the interior for a larger glue base for the lower and upper plates. Popsicle crossbar to brace the lower plate was also glued in place. Bottom plate was coated with CA glue and two coats of wood glue.

 

[ljwilley]

Nice! Looking forward to the build!

 

[kuririn]

So that we can visualize what you're building:

 

[Raptor 2]

Constructed seven centering rings and four cardstock transitions for the nose cone. the top end CR is glued in place first and then each transition is double layered by gluing sections of cardstock to the interior of each transition with RC canopy glue. The bottom end CR is then glued on using the same glue. RC canopy glue is used as it does not absorb any moisture into the cardstock paper. Top end nose cone transition has a wood bead glued into the top opening.
Sections are then placed over the centering BT-20 tube and glued in place again with canopy glue and CA glued to the BT-20 tube. Sprayed with primer filler.

 

[Raptor 2]

Four layers of orange cardboard were applied (3M double sided tape) to the two side booster BT-60 tubes to increase the diameter to 45mm from 41mm. this increased the weight of each side booster tube from 17.19gm to 68.64gm.The ejection baffle has been glued in place using canopy glue and the upper portion of the sustainer has been glued to the lower end engine section. Shown in the picture is the lower end with coupler in place. Constructed two bulkheads, six centering rings and two 10mm long spacer tubes for the bulkhead. Spacer tubes were glued to the bulkheads and then these were glued in place in the two side boosters with epoxy glue. The three centering rings were then glued in place with carpenters wood glue. Picture shows the rings and bulkheads as they would hold the BT-20 inside the BT-60 side boosters. The BT-20 fin tube is removable. Applied wood filler to the nose cone and sanded smooth. Then applied another coat of primer- filler.

 

[Raptor 2]

Applied another light coat of wood filler to the nose cone, sanded, sprayed with primer again, sanded and sprayed with flat white followed by a satin clear coat. Printed the wrap from AMX paper space at 135.5% on 28 lb paper and applied it with double side 3M tape to the PLF. Constructed the lower skirts for the side boosters consisting of three centering rings, two cardstock transitions and one cardstock engine nozzle for each side. the larger transition is double layered for extra strength. The picture shows a test fit of the parts. Parts are all glued using RC canopy glue.

 

[Raptor 2]

I cut the top end of each side booster tube 25mm from the top to assist in gluing the angled nose cones to the tube. I left a small extension on the sustainer side of each to assist in lining the nose cone up vertically with the tube. Constructed the nose cones from prints on cardstock of the AMX plans, double layered and inserted a 25mm polypropylene plastic sphere in the top of each. All glued with canopy glue. Applied a bead of canopy glue to the inside edge of the nose cone and inserted it on the tube top. Once it dried I applied two more fillets of glue to the inside of each nose cone. When that dried I coupled it to the top of each booster tube. Printed AMX wraps for each side booster on 28lb paper and applied them using 3M double sided tape. Then glued the lower skirts and nozzles to each booster using canopy glue.

 

[Raptor 2]

Sustainer wraps applied to the BT-70 with 3M double sided tape. The side booster have yet to be secured to the sustainer using 2 basswood strips 25mm long for each. Numerous details also still have to be constructed before it is done.