Quick answer

For a 4-inch Goblin, the LOC Precision 4" Goblin Fin Set (product 883962) is the safe default: it is a four-fin set cut from 1/4-inch material with tabs sized for a 54mm motor tube, and it is made for LOC Precision Goblin kits. Order it if you are replacing damaged fins or upgrading a stock Goblin build. If you are still choosing a complete rocket, start with the kit first and treat the fin set as a later replacement part.

What the 4-inch Goblin fin set actually includes

The LOC Precision 4-inch Goblin Fin Set ships as a set of four fins. Each fin is precision-cut from 1/4-inch thick material. The fin tabs are sized to fit a 54mm motor tube, which is the key dimensional detail for through-the-wall mounting. The set is described as a direct replacement or upgrade for your Goblin rocket.

That combination matters because a fin set is not a universal part. The tab length, tab width, and root chord must match your airframe and motor mount. A set cut for a 54mm tube will not drop into a 38mm mount without modification. Confirm your motor tube size before ordering.

Check your airframe and motor mount first

Before you order any high power rocket fin set, measure three things: your airframe outside diameter, your motor mount tube diameter, and your existing fin slot length. The 4-inch Goblin set is built around a 4-inch airframe and a 54mm motor tube. If your Goblin uses a different mount, this set is not a bolt-in replacement.

If you are building from a kit, check whether the kit already includes fins. Many Goblin kits ship with fins in the box. Buying a separate fin set makes sense when you are replacing a broken fin, upgrading to a stronger set, or building a scratch project around Goblin dimensions.

When 1/4-inch thickness is the right call

The 1/4-inch thickness of this fin set is a durability choice. Thicker fins resist flutter and landing damage better than thin ones, and they hold up to repeated flights. The tradeoff is weight and drag. On a smaller motor, a heavier fin set can shift your center of gravity and reduce stability margin.

If you fly mostly F and G motors in a lightweight Goblin, stock thinner fins may be fine. If you are moving to higher thrust or flying on fields where hard landings are common, the 1/4-inch set is the more forgiving option. Match the fin to your motor plan, not to the largest motor you might someday use.

Replacement versus upgrade: know which you are doing

A replacement fin set restores the rocket to its original configuration. An upgrade fin set changes performance or durability. The 4-inch Goblin set works for both, but the decision rules differ. For replacement, match the original fin profile and thickness so the rocket flies the same way. For an upgrade, accept that added thickness changes mass and may require a stability check.

If you are also considering a complete kit, the V2 4" (product 883857) is an advanced-series kit with factory pre-slotted airframe and through-the-wall fin construction. It uses a 38mm motor mount and can fly on F50 and G motors with an optional MMA-2 adapter. That is a different build path than buying fins for a Goblin you already own.

Decision rules for ordering a Goblin fin set

  • Rule 1: Match the motor tube: The 4-inch Goblin fin set has tabs sized for a 54mm motor tube. If your Goblin uses a different mount, do not order this set expecting a drop-in fit. Measure your motor mount before you add to cart.
  • Rule 2: Match the airframe: This set is built for a 4-inch Goblin airframe. Confirm your airframe outside diameter and existing slot length line up with the fins you are replacing. A 4-inch airframe is not the same as a 4-inch fin span. Check both.
  • Rule 3: Choose thickness by motor plan: 1/4-inch fins add durability but also mass. If you fly small F and G motors, stock thinner fins may be enough. If you want a tougher airframe for harder landings, the 1/4-inch set is the better choice. Pick the fin for the motors you actually fly, not the biggest motor you might try.
  • Rule 4: Replacement or upgrade: For replacement, match the original fin profile and thickness. For an upgrade, plan to recheck stability after adding mass. State your goal before ordering so you buy the right set once.

Product facts to compare

  • 4" Goblin Fin Set: This 4-inch Goblin Fin Set from LOC Precision is a direct replacement or upgrade fin set for your Goblin rocket. Each set includes four fins, precision-cut from 1/4-inch thick material. Fin tabs are sized to fit a 54mm motor tube and it is compatible with LOC Precision Goblin kits. The 54mm tab sizing and 1/4-inch thickness are the two numbers that decide whether this set fits your build. Verify your motor tube diameter and your slot dimensions before ordering.
  • V2 4": The 4" LOC V2 Rocket Kit is one of the ADVANCED SERIES of kits, with factory pre-slotted airframe and through-the-wall fin construction. It comes standard with a 38mm motor mount but flies on F50 and G motors using an optional MMA-2 adapter. If you are shopping for a complete high power kit rather than a fin replacement, the V2 4" shows what a pre-slotted, through-the-wall build looks like. Its 38mm mount is smaller than the Goblin fin set's 54mm tab target, so the two are not interchangeable.

Who should order this fin set

Best for

  • Goblin owners replacing a damaged or broken fin on a 4-inch airframe
  • Builders upgrading to 1/4-inch thick fins for more durability
  • Anyone building a scratch rocket around a 4-inch airframe and 54mm motor tube

Not for

  • Goblins with a motor mount other than 54mm
  • Builders who have not yet chosen a kit and need a complete rocket instead of a part
  • Flyers looking for a lightweight fin set for small-motor, low-drag builds