Public Enemy FatBoy (4)

Public Enemy - FatBoy (4)

Contributed by Justin Cartisano

Construction Rating: starstarstarstarstar_border
Flight Rating: starstarstarstarstar_border
Overall Rating: starstarstarstarstar_border
Manufacturer: Public Enemy
Public Enemy 4" Fatboy

Brief:
The Public Enemy 4" Fatboy is a single stage high power rocket with 38mm motor mount and parachute recovery.

Construction:
Here's what you get:

  • 1 pre-slotted 4" airframe, already marked for the lug and everything. It also has a glassine covering to make it smooth.
  • 1 hefty V2-ish nosecone with a thick molded loop for attachment. The finish is a little rough but it looks sturdy as hell.
  • 4 1/4" thick plywood fins already beveled to a 45 degree angle.
  • 1 38mm motor tube.
  • 3 particle board (MDF) centering rings. One of them is slotted to pass the shock cord through.
  • 1 30" orange rip-stop chute with a welded ring and a quick link.
  • 1 15' x 1/2" very bright florescent orange nylon shock cord.
  • 2 beveled copper launch lugs, 3/8" diameter.
  • 1 vinyl Fatboy sticker
  • 2 pages of written instructions with 1 diagram.

A lot of cool stuff for only 54 bucks. I think the kit was pretty easy. It was my first high power kit (I certified level one with it) and I managed to get it together with out too much trauma. Everything lined up nicely and it's incredibly sturdy. Building the fins and motor mount separately , and then installing them is great. The slots in the tube line the fins right up for you. The pre-slotted and marked tube was a big help. The pre-beveled fins were a winner also.

Public Enemy 4" Fatboy The directions were sparse but adequate, although I wish the manufacturer would have included more motor recommendation information. The Fatboy page on their web site just says "for H and I motors", and if you go to their Kit Specifications page, it lists the simulated heights & recommended delays for the G80 and I284 motors. For a new guy wanting to certify on an H motor, this information sucked. Only two recommended motors with a BIG difference between them. The directions contain no motor data whatsoever.

The stock kit has a glued in shock cord. I didn't think this was a good idea, but I installed as per instructions. I haven't heard of one failing but I decided to put in a U-bolt in the top centering ring as a backup just in case, so if the epoxy joint fails or if my shock cord gets toasted, I can put on a new cord with a quick link. I also added a Kevlar® shock cord and chute protectors.

Public Enemy 4" Fatboy I added a Giant Leap motor retainer too, which is just two T-nuts and clips. It worked well and was cheap. If I had more money I probably would have bought a Slimline retainer though.

The manufacturer estimates the weight at about 1 1/4 pounds. I added 5 ounces of nose weight for stability and mine, which was built a little heavy with all 30 minute epoxy, came in right at 3 pounds.

Finishing:
I did a pretty simple paint job, but the thing is big enough to stripe or detail easily. It comes with a cool silver vinyl Fatboy sticker that I haven't put on yet.

Construction Rating: 4 out of 5

Flight:
I flew for my level 1 certification with a H123 with a medium delay in a Dr.Rocket 2 grain 38mm case. If flew arrow straight and had a perfect recovery.

The second flight I used a G79 in a 29 mm case and a 38-29 adapter. This was a mistake. It did not have enough power and the delay was too long. (I did not know how to judge these things at the time). It made a good thump when it hit the ground coiled in it's chute. The thing is so sturdy though, I only had to straighten and re-fillet a fin. I'm in the process of repainting it now so I'm glad I didn't put on its Fatboy sticker yet.

Public Enemy 4" Fatboy

Recovery:
I used the stock recovery system (except the additions mentioned above) and everything worked fine. The 30" rip stop chute dropped it a little fast (some people upgrade them to larger ones with spill holes) but I didn't mind that. The Fatboy is a sturdy rocket and I didn't want it to drift to Spain. The 15' florescent shock cord made it easy to spot on the way down. I don't think I'll use a black shock cord again.

Flight Rating: 4 out of 5

Summary:
I think it's a great, inexpensive level 1 rocket that is easy to build and fly. I would definitely like to see more motor data from Public Enemy though. If not on the instructions, at least on the web site, though both would be best!

Overall Rating: 4 out of 5

TIPS:

Tip 1-
This tip comes from a post on The Rocketry Forum. When you remove the pre-scored slots from the marked body tube save the four card board pieces. Use the scrap to fill the space behind the fins after you insert the fins and motor tube. It works great, and makes the tail nice and neat for finishing.

Tip 2-
When you epoxy in the fins and motor tube (with the filler pieces from tip 1) use a piece of thin steel wire to pull together the bottom of the tube behind the fins. Make it snug with the bottom centering ring. I did this and it kept everything nice and straight.

Flights

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