4″ Goblin

POLECAT ROCKETRY Model #

Description

The Goblin 4″is a small but versatile high power rocket. Capable of flying well on F and G hobby motors, it makes a great entry level rocket. The Goblin 4″ can be used for L1 and L2 certifications. It has a 54mm motor mount and will support motors up to 4 grain K reloads. The Goblin is a very tough and fun rocket designed with both the beginner and expert in mind.

Additional Information

Through the wall fins
Fiberglass molded nose cone
Pre-fiberglassed and pre-slotted body tube
Baltic Birch fins and centering rings
54mm motor mount
Tubular nylo shock cords
Shock cord mounting hardware
This kit is designed to fly on motors ranging from F through K impulse. A 24″ to 36″ parachute is needed depending on motor selection and landing conditions.

Instructions

Photo Gallery

Build History

03/30/2008 – Purchased Polecat Rocketry 4″ Goblin from Nocturnal Knight Rocketry for $80.00 (Retail – $89.95)
06/08/2008 – Cut motor mount tube to 7″ so the U bolt would extend beyond the end when the centering rings wer positioned to the length of the forward end. Epoxied forward centering ring with 30 minute epoxy and positioned the U-bold forward. Filleted the forward centering ring joint. Mounted aft centering ring to motor mount tube without epoxy. Epoxied motor mount assembly into body tube. Epoxied 2 of 4 fins to motor mount tube with 5 minute epoxy.
06/09/2008 – Removed aft centering ring and epoxied fins to motor mount. Filleted 2 fins at joints.
06/10/2008 – Filleted remaining fin joints with 30 minute epoxy/
06/19/2008 – Epoxied aft centering ring in place with 30 minute epoxy. JB Welded 54mm retainer on aft end of motor mount.
06/20/2008 – Filleted aft ring to body tube with 30 minute epoxy.
06/21/2008 – Filleted all external fin joints with 5 minute epoxy.
06/06/2009 – Painted fins and body tube John Deere Yellow and nose cone Black. Masked all but on fin and painted it Gloss Black and later removed masking tape.
07/22/2009 – Applied upscaled Goblin water slide decals to the fins and applied a piece of black electrical tape to body tube. This completes construction of 4″ Goblin.

Flights

Date	Location	#	Motor	Comments
03/07/2010	Sim’s Farm	TRA1	I117FJ	Maiden flight. Great flight for about 100 feet then a beautiful loop de loop several times and landing on the ground before the ejection charge went off. Later in the day realized I had used the wrong (lighter) nose cone.
12/11/2010	Sim’s Farm	BS46	I229	Ejection did not ignite and whistling rocket was buried up to the fins. Model material for the bone yard.
11/09/2013	Sod Farm	BS73	E9-6	CATO. Propellant blew through the body tube pushing out the recovery device and leaving the rocket undamaged.
05/02/2015	Sod Farm	BS93	F29	Under-powered. Flew Horizontal about 50′ above ground level.
09/13/2015	Sod Farm	BS97	F16-8
09/13/2015	Sod Farm	BS97	F36 BS	Long walk to recovery. ~15″ short of landing in Bean Field East of Launch site.