I thought it would be helpful to do a build thread on the Rocketry Warehouse Formula 75. Lots of these were sold during Rocketry Warehouse' Black Friday sale. This build thread can be used as a reference to build most other fiberglass kits too.
Last year I bought a Rocketry warehouse Formula 54 fiberglass kit and was very impressed with the price and quality. This year I bought a couple of Formula 75 kits during Rocketry Warehouse’s Black Friday Sale. This is an upscaled version of the Formula 54 kit (54mm) kit. This kit uses a 75mm airframe, hence the name. The Formula 75 is manufactured by Performance Rocketry for RW and is a 3” diameter, 4 foot tall, all-fiberglass kit with color impregnated parts. It is supplied with Performance Rocketry’s latest filament wound nosecone with integrated graphite tip. The kit weighs about 3.75 Lbs built and flys on G to J motors. It comes with a 38mm motor tube. It also comes with a nice, black vinyl decal. At a sale price of only $59.95, these kits were an absolute steal. Heck, the nosecone alone is worth the price! Even at the regular price at $89.99 is still a bargain in my opinion. Rocketry Warehouse currently has them on sale for $79.95. This would make an ideal level 1 rocket and could even be used for level 2 with a small J motor taking it to around 6000'.
One of the things that attracted me to these kits aside from the price, was the variety of colors they come in and that they do not require painting. Either fly them naked or gloss them up with wax or the like. You might even consider a clear coat of paint to make the colors pop. All the kits come with black G10 fins and black nosecone. The 7 fruit colors offered during the sale were Lemon, Lime, Tangerine, Cherry, Plum, Blue and Cranberry. The Blue and Cranberry seem to have been dropped after the sale ended. A conventional natural-colored kit is also available. I chose both Lime and Cranberry versions.
Here’s what you get:
• 3 Inch G12 Colored Fiberglass Airframe 30 inches long
• 38mm Motor Mount G12 Colored Fiberglass 10 Inches long
• 3 G10 Black Fiberglass 3/32" Thick Fins
• G10 Black Fiberglass Centering Rings
• 3 Inch Black Filament Wound 5:1 Von Karman Nosecone
• G10 Black Fiberglass Bulk Plate for Nosecone
• Black vinyl decal
Another interesting feature of the kit is the black filament wound nosecone. It is VERY strong and is supplied with a black 75mm coupler which is glued into the nosecone to form the shoulder. The coupler is a precision fit in both the nosecone and airframe tube (No sanding required) and offers a crisp shoulder unlike anything you can expect from the molded style nosecones. Its embedded graphite tip is nearly indistinguishable from the nosecone itself as it is centerless ground at the same time as the nosecone. The nosecone’s appearance somewhat resembles carbon fiber and it is quite handsome. The separate shoulder tube also offers some advantages as you will see later. The disadvantage? Like the G12 filament wound airframes, this nosecone is heavy at 15 oz. That said, the advantages of strength, no seams, no sanding, uniform finish and thick walls far outweigh this disadvantage. Did I mention NO SANDING REQUIRED?
Having recently become a fan of the Garmin DC40 GPS dog tracker in my larger projects, I planned to incorporate it into this smaller diameter build. More on this later.
I used West Systems 105/205 epoxy for the build and JB Weld for the areas where I required a strong heat resistant bond. I used Pro Line 4500 black epoxy for the external fin fillets. I began construction by washing all the parts in soapy water to remove any mould release. Then I roughed up the 38mm motor tube with 60 grit sandpaper so the epoxy would key into the surface for better adhesion. I elected to use an Aeropack 38mm motor retainer.
I began by using my trusty two foot long ½” dowel with 36 grit aluminum oxide sandpaper taped to one end to rough up the interior of the airframe where centering rings, fin fillets and rail button retaining nuts would be glued. The super coarse 36 grit makes this effortless. I had cut some of this sandpaper from a 1” x 42” sanding belt I bought for this purpose. I keep 36, 60 and 80 grit belts on hand for these kind of jobs. They are cheap, easy to store rolled up and have a very tough cloth backing.
Photo of the green kit by Gary T.