This is designed for Testor's/Italeri's 1/72 scale Blackbird kit, and specifically test fitted to the kit No. 145 boxing. This goes with my SR-71 Engine Inlet design. Without the Inlet, after removing the internal mounts from the Italeri kit, the Spike has nothing to locate on. I've broken them up in order to allow optimization for the different materials; Strong and Flexible allows a reduced part cost, while Frosted Ultra Detail allows for much higher detailing in the areas where it's needed, such as on the Inlet Spike.
I've designed the Engine Spike to be adjustable in length, as on the real article. Also note the air siphoning holes just past the Spike's maximum diameter. These would draw off thickening boundary layer at high mach numbers, drawing the air into the Spike body, and then expelling the air outboard, via the hollow cruciform struts connected the the bypass doors ahead of the engine face. Also provided are are the air straighteners ahead of the turbine face, as well as the J58 turbine itself.
New to rapid prototype parts? Here are some suggestions of how to handle Frosted Ultra Detail:
: For starters, you'll want to rinse the parts in acetone to remove the wax support structure (some always seems to remains behind, stuck in the nooks and crannies), and wax support structure residue. Note to use extreme caution in that there is the possibility of damaging the model at this stage.
What I did was to find a large enough Tupperware or equivalent, and pour in enough acetone to partially submerge, then used an old paint brush to brush on acetone in the areas not submerged. Do this 3-4 times, no more than 1 minute at a time, rotating it to submerge areas not previously, and then taking it out of the acetone "bath" in between. Monitor the part the entire time to reduce the possibility of any part damage from the acetone. Do this BEFORE you begin any assembly given the use of acetone and the donor kit's plastic; cleaning the parts once assembled to the donor kit will no doubt lead to tears.
: Use Cyanoacrylate glues to adhere the RP parts to the plastic kit, or RP parts to RP parts.
: The Frosted Ultra Detail rapid prototyping produces some of the finer surface finishes. However, that doesn't mean it's completely smooth; there will be step/striations. As for how to deal with these striations, give the parts an initial sand to give the surface some teeth (400 grit), and then get yourself a good spot-filling spray primer. I'm a fan of Dupli-Color's Filler Primer; it can be found in the paint section of most auto part stores. Multiple coats of that, sanding between each, should eliminate the striations in the model surface.