Scratch 4" Fat Boy Upscale

I ordered a 4" fiberglass Nose Cone from the Rocketry Warehouse to scratch together a mid to high power upscale of an Estes Fat Boy. Thanks go to Dave "Green Jello" for telling me that Rocketry Warehouse has 4" Nose Cones. Scaling up from the original 2.6" diameter to 4" diameter meant a scale factor of 1.54X.

I purchased a length of 4" Body Tube, two Centering Rings, a 29 mm Motor Tube and an Estes 29 mm Retainer from my local hobby shop, and a U bolt and 1/8" plywood from a hardware store. I cut the Body Tube to 12.31" long and cut some slits for Through-the-Wall Fins.

Below are pictures of the slotted Body Tube, assembled Motor Mount, and Fins....

I installed the Motor Mount and Fins into the Body Tube with epoxy.

The new 4" Rocketry Warehouse Nose Cone isn't the exact same shape as the original Fat Boy Nose Cone, but it is definitely close enough. After final assembly, I will paint it like a stock Fat Boy. For up-scaling the stock Fat Boy decals, I will use my Silhouette Cameo cutting machine to cut out some painting masks.

Next up are epoxy Fin Fillets, gap filling and sanding. I also need to add a bulkhead with a u-bolt or eye-bolt into the Nose Cone for Shock Cord attachment.

The pictures below show all the parts, the dry-fit structure, and a side-by-side with a standard-sized fat Boy to show scale. I also have a 5.5" Polecat Fat Man, and this new 4" rocket will fill the gap nicely between the 2.6" and 5.5" Fat Boys.

Nice ! Can't beat a FatBoy "Fat Boy" build thread. Love the Fatty in every scale.

This build tempts me...

This is looking down into the Rocketry Warehouse 4" fiberglass nose cone. I epoxied a 3" LOC bulkhead with an eye bolt at the top of the nose cone so I can have a secure attachment for the shock cord. I also coated the interior surface of the nose cone with epoxy to cover the fibers and give it a smoother surface. I cut down the long shoulder on the nose cone to about 2 1/2" long.

FatBoy said:

I ordered a 4" fiberglass Nose Cone from the Rocketry Warehouse to scratch together a mid to high power upscale of an Estes Fat Boy. Thanks go to Dave "Green Jello" for telling me that Rocketry Warehouse has 4" Nose Cones. Scaling up from the original 2.6" diameter to 4" diameter meant a scale factor of 1.54X.

I purchased a length of 4" Body Tube, two Centering Rings, a 29 mm Motor Tube and an Estes 29 mm Retainer from my local hobby shop, and a U bolt and 1/8" plywood from a hardware store. I cut the Body Tube to 12.31" long and cut some slits for Through-the-Wall Fins.

Below are pictures of the slotted Body Tube, assembled Motor Mount, and Fins....

Click to expand...

Nice work! I just think the attachment point is overkill and adds weight but just my :2:

It definitely is overkill, but it was easy to do and will never need to be replaced.

I finally got back to working on this scratch build and finished it up.

The picture below shows the following four different sizes: (1) 1.64" dia scratch built from a Baby Bertha nose cone, 18mm motor mount, stickers from StickerShock (built a few months before Estes released the Mini Fatboy). (2) 2.6" dia Standard production Estes Fatboy kit but built with a 24mm motor mount. (3) 4" dia newly finished scratch-built, 29mm motor mount stickers are home made on my Silhouette Cameo cutting machine. (4) 5.5" dia Polecat Aerospace Fat Man kit, 54mm motor mount, stickers from StickerShock.