To reinforce the struts to prevent breaking, a piece of bent .025" music wire (lower left) was placed into the mold at each of the two half-strut locations. The dark wires are slightly visible in the cast struts.

Two "whiskers" on the half strut at lower right are from vent holes in the mold. Part was not cleaned up at the time this scan was taken.

Bottom of photo : Special wind-up tool made of square brass tubing. This engages the output shaft of the timer, which is ground to a 1/16" square cross-section.

Also see the DECALS page.

An original kit Aft Skirt was used for the proper curvature of the cast flanges, after filling a flange mold with Alumilite the aft skirt was pressed into place.

As shown at bottom, several flanges were cast and allowed to cure a long time to stiffen before removal fromt he Aft Skirt.

The flanges were later glued to a vac-formed aft skirt.

HS-60 servo in center for SRB sep activation. Spring-loaded pushrods to latches allow latches to be manually moved to allow for SRB attachment, and for servo to "overdrive" the pushrods.

Latches are cast in 2 parts using one-piece RTV mold (bottom). 1/8" hole is cast in part by use of a 1/8" rod (mold release waxed) inserted before casting. Holes for hinge pin also cast into parts by use of 1/32" brass rods. After Alumilite has gelled reasonably firm, but not totally hardened, the 1/8" rod and 1/32" pins are rotated enough to "unfreeze" them, then left in place for a few more minutes before removing the rod and pins completely and removing the parts.

For more info on how the latches work, see the Shuttle model web page. These latches are a modified improved design from the ones shown in the drawing on the web page.

Horizontal light gray line is Squadron Putty applied over the joint of the two intertank wrap halves. It was still drying when this was taken, later sanded down.

After trimming, and after the Aft bulkhead was built, the position of the hole for the engine nozzle was determined (the extended nozzle of an F25 sticks thru the hole). The hole is cut to match a tube coupler for BT-20. The coupler is saturated with thin CA to give it some heat/flame protection. The tube is used to ensure that no hot gases get trapped along the opening of the hole, it extends up about 3/8" inside the Aft Dome. It has worked well, no exhaust damage to the dome on either the NARAM or boilerplate models.

Yellow plastic ring at top has 4 angled guide ramps to help slip the engine mount tube into place.

In scan at right, cream colored parts are cast copies of fairings from the Monogram kit. Large one at left for the Lox line, the one at top center is for the "Beanie cap", where the conduit lines from the ET nose start down. Assembled conduit lines on the right side.

ET-Orbiter%20struts.jpg

ET/Orbiter Struts. Cast parts based on Monogram kit parts as masters for RTV molds. The Aft struts are fully assembled, from three cast parts. The 90 degree bend for the Lox line is shown, with Orbiter Sep sensor wiring (yellow) running from it. Barely visible inside of the Lox line is the very small lever switch that was the orbiter sep sensor.

Orbiter attach hardpoints are 1/16" brass pins. If you look close you can see them near each end of the horizontal beam. The beam was drilled to accept these pins which were then CA'ed in place. Acceleration loads are transmitted to the orbiter by these pins (and the entire aft strut assembly)

Near bottom, the forward attach strut. It is reinforced by a piece of 1/32" music wire in each leg, bent as needed. The music wire extending out of the bottom allows for the strut assembly to be attach to the ET merely by drilling two 1/32" holes to the correct spot on the ET, no gluing. It is free to pivot and can even be easily replaced. The top part of the strut assembly extends inside of the orbiter nose about 5/8", a spring assembly inside of the orbiter nose pushes down on this to help with separation when the sep latch is released.

Light orange parts of conduit struts are white decal material that was airbrushed with the same color. This orange-painted decal was used in other places as well.

SRB Aft attach half-round struts visible to the left and right.

Conduit strip in place, along with beanie cap, fairing, and so forth.

Lighter orange ramp was made by gluing two pieces of plastic to a sharp angle then using that as a mold to cast a long wedge cross section part. After hardening the long piece was trimmed and sanded to achieve the proper angled shape for the front and read of the ramp. Then the part was cut into two pieces, one for the nose and one for the ET intertank.

Not visible are two 1/32" holes in the ET nose side, where .025" "remove before flight" pins are inserted to disarm the ejection charges and keep the flight computer power off. The holes are between two of the conduit lines. This area is pointed out better on the shuttle model web page photos of the NARAM-41 model.

Lighter orange bands along the top and bottom of the intertank area are white decal material, painted orange.

The second one was used for three remove before flight switches, thrust detect switch, and liftoff sensor switch. To the right of it is shown one of the special assemblies that was built to house the switch for the remove before flight pin switch method. Two of those were used in the ET Nose (Computer ON, Ejection ARM), and one in the orbiter for R/C power ON (on being when the pin is removed).