Coldfire airframe components ready for assembly

View tube construction

The three fins are made of G10 fiberglass sheet that is 0.125" thick. They are a custom size and were purchased at Giant Leap Rocketry. I only had to cut the small slots for the centering rings and sand the leading and trailing edges.

Patrick does a great job, uses top rate material and delivers fast.  The price is right too!

The aluminum motor thrust plate was custom made by Front Panel Express.  I downloaded their CAD software and designed the plate with all the holes in it. I then pressed the "submit" button to send the design to them and the finished item was delivered to me within two weeks at a very reasonable price. It is a precision machined part.

The booster aft centering ring is also made of aluminum and has threaded holes in it that line up with the holes on the thrust plate. This ring was too thick to be made by  the folks at Front Panel Express so I had it custom machined at a local machine shop.  Unfortunately, that was rather expensive. 

A custom aluminum backer plate with threaded holes is used to hold them in place. These backer plates were also made by a local machine shop. 

The two piece tail cone assembly is made from aluminum and sold by Aero Pack Inc.   The part number  is TRA5439PB.  The black tail cone unscrews to allow access to the bolts on the aft centering ring on the booster.  The smaller threaded section of the tail cone assembly is bonded to the motor tube with JB Weld epoxy.

The hybrid motor adapter tube is made from a section of 2.152" ID flexible phenolic tubing from Giant Leap, three wood centering rings from A1CenteringRings.com and the aluminum motor thrust plate described previously on this page.

Coldfire uses a plastic "Pinnacle" nosecone from Giant Leap Rocketry.  It is a 5:1 Ogive design with a nice long shoulder length on it.  The base of it was drilled out and a payload tube was added as seen here.

The nosecone retainer ring is an aluminum ring fabricated by a local machine shop.  This ring mounts into the base of the nose cone and holds a payload compartment tube in place.  The ring has threaded holes for screws that allow the tube to be removed for access to the payload inside it.  Click here for more details.

These bulk plates were purchased from A1CenteringRings.com.

Bulkhead B3 is for the forward end of the altimeter module.  It is also made by epoxing together two  wood plates of different thicknesses and different diameters and then drilling the center hole.  These were also purchased from A1CenteringRings.com.

Bulkhead B4 is the forward end of the altimeter bay mount.  It was made by epoxing together two wood plates from A1CenteringRings.com.

It was purchased from A1CenteringRings.com.

Coldfire uses two stainless steel U-bolts as "hard points" for securing the recovery system harness.  These were purchased from McMaster-Carr and are part numbers 8896T92 and 8896T104.  The smaller one is used in bulkhead B1 at the top of the booster section.  The larger one is used in bulkhead B2  at the aft end of the altimeter module.

The altimeter module is on the left side of the photo.  The altimeter mount is on the right side of the photo.  The altimeter mount is epoxied into the airframe.  The altimeter module is removable to service the altimeters and ejection charges.

This photo shows the main parts of the altimeter module except for the actual electronic altimeters themselves.  It is all held together by the threaded rod that runs down the center of the assembly.

Click here to see all the details.

The altimeters selected for Coldfire are the Missile Works RRC2 units. Unfortunately, these have been discontinued and are no longer available. They mount on each face of the wood block shown above.

The Coldfire decals were designed on the AutoSketch CAD program. (As was everything else about Coldfire!)  The design files were then used by a local sign shop to cut the vinyl decals to shape.

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