This model rocket came to me as a Father's day gift. My son Max and I decided to add to the fun of building this skill level one rocket kit by giving it a 24mm motor mount. After all, the face card reads "Heavy Duty Construction" and the rocket comes with through-the-wall fins. That's just asking for an upgrade. The slotted body tube was a very nice surprise. The balsa fins are rather unfortunate, slotted fins beg to be made of plywood, not balsa. If you decide to modify the Fat Boy in the same way, be sure to trim the fins. Increasing the size of the body tube makes it so you can't get the fins in the slots all the way. Trimming the root edge of the fins takes care of this. This modification changes the center of gravity of the rocket and requires adding nose weight to ensure it remains stable. I added 2 oz. which may have been too much. The exact amount to use will be depend on the construction, which is unique for every rocket built.

Parts List

This flying model rocket kit comes complete with all the parts required to build one Fat Boy.

- plastic nose cone
- pre-slotted body tube
- cardboard centering rings
- elastic shock cord with shock cord mount
- motor tube, engine holder ring and engine hook
- launch lug
- 3 die cut balsa fins
- parachute assembly
- decal sheet
- instructions

Hobby supplies needed to build the model include pencil, sandpaper, glue, and a ruler. Launch and finishing supplies are not included with the kit.

Construction

Usually, you'd start by marking the motor tube to cut a slit for the motor hook. We didn't install the engine hook, a motor retainer was used instead.

Next are the centering rings. Plywood centering rings were used, to go with the 24mm motor mount and PMR. The elastic shock cord mount provided with the kit was not used either. Two holes were drilled in the forward centering ring and some Kevlar cord was tied to it and epoxied in place. This should be a sturdier shock cord setup.

A hobby knife was used to remove the fins from the balsa sheet. The fins were sanded and filled with some Elmer's watered-down wood filler.

The motor mount assembly was glued into the airframe tube and the fins attached. Lastly, the launch lug was glued in place. Even with the modifications, this rocket kit is quick and easy to assemble.

Finishing

After a coat of initial Rust-Oleum automotive primer, the Fat Boy was given a coat of Krylon white primer. The rocket was sanded smooth between coats.

The fins were painted Testors Blue (#1208). Once the paint dried, the fins were masked off and the rocket's body and nose cone were painted Testors Gloss Bright Red (#1231). Once that paint had dried, the decals were applied. To complete the job, Gloss Clear Coat (Testors #1814) was applied all over.

Measurements

Given its name, it should come as no surprise that this flying model rocket is on the stubby side. It measures 12.9" long with a 2.6" (BT-80) diameter. The face card lists a weight of 3 oz., ours obviously came out weighing quite a bit more.

Flight Data

Estes Industries suggests these model rocket engines for use with the Fat Boy : B4-2, B6-2, C5-3 and C6-3.

As we'd upgraded our Fat Boy a wee bit, an F24-4 was used for the first flight. And what an awesome flight it was. Nice flame, good amount of smoke, very nice altitude (900+ feet). A 12" nylon parachute was used.

The rocket was recovered quickly and it immediatly became obvious that the nose cone was missing. The eyelet on the nose cone must have broken, something I'd never see happen before. The nose cone will be replaced and the shock cord will be make several feet longer, in the hopes of avoiding a repeat. We also had a MicroBeacon attached to the nose cone. The beeper was also not recovered. Max and I walked around for a while, listing for the beeps, hoping to recover at least the locator. No such luck.

Video : F12-3 Deploys Too Early