(07/06/00) I'm a big fan of what I call "stubby" rockets, which have a 10:1 Length to Diameter ratio or less. So when I saw Yank Enterprises' "The Bullet" I wanted to give it a try. This is also my first Yank Enterprises kit so that would also be a new experience.

See my 4" Stubby Rocket Comparison Page

The Bullet is not a complicated looking rocket, nor did it turn out to be complicated to build. The "stats" are interesting though: 4" diameter, 40" length and weighs in at 40 ounces, it also has as close as you can get to a 40mm motor mount (38mm). It might sport the name, 444. The Bullet fits, though, due to its long nose cone, short body and small fins.

The Bullet includes a pre-slotted Flexible Phenolic main body tube which is 24" long. The plastic nose cone makes up the remaining 16". There are four (4) 1/8" thick Baltic birch plywood fins that are pre-cut. There are also two (2) 1/4" plywood centering rings. The motor mount is 38mm and about 12" in length. The recovery system is solid, including a 5/16" eye-bolt and two Quick Links. My kit came with 20 feet (the material list says 15') of 9/16" tubular nylon for the shock cord. There are also two (2) 1/2" launch lugs. There are no decals or lettering included.

CONSTRUCTION:

The instructions are printed on 4 pages of single-sided 8x11 sheets of paper and consist of 7 steps. There is a colored photo of Yank's paint scheme of The Bullet, a materials list, the construction steps and a pre-flight preparation paragraph. There are a few illustrations, which are enough for any experienced builder. I had to read the last step several times to understand, however, that could be for one of two reasons: 1) there are a lot of words packed into this step which is to add the nose cone and the parachute to the shock cord, or 2) because the attachment technique is very different from what I am used to, which I'll describe later.

As mentioned, this rocket is not complicated and essentially is a 4FNC (4 fins and a nose cone) rocket. However, there were a few construction items that are worth noting.

The motor mount uses 1/4" centering rings. Bravo! Even though the kit didn't include any motor retention hardware, I added two T-nuts and with the 1/4" centering rings they were flush to the surface. Usually with the common 1/8" centering rings the T-Nuts would stick up!

The cuts of the wood components were excellent. Perfect fit for the centering rings, both into the body tube and around the motor tube. The fins were all exactly the same and fit correctly into the pre-slotted body tube. The fins are made to reach the motor tube for a secure attachment.

The recovery system is sturdy. The 5/8" Eye-Bolt is attached to the upper centering ring with two nuts and two washers for a secure tie-down. The instructions then indicate that the tubular nylon is to be thread through the "eye" and folded over a length of 4". This is then soaked in epoxy and adhered together. I took the instructions advice and wrapped mine with tape after soaking it with epoxy. A similar folding over method is done at the other end of the shock cord and a Quick-Link is attached. Four (4) feet from the booster is where the other Quick-Link is attached and that is attached to the nose cone.

This is a totally new technique for me. The shock cord is attached to the body, then four (4) feet later to the nose cone, then fourteen (14) feet later it is attached to the parachute. I am used to the nose cone being the last attachment and the parachute somewhere up by, but under, the nose cone. When I asked them, Yank told me that this will decrease the amount of sway and spin!

There was only one rather disappointing aspect of the kit. The nose cone outer diameter is less than outer diameter of the body tube. Not by much, but I would say there is a 1mm difference all the way around. Not too big of a deal. I will soak CA into the upper edge of the body tube and sand this lip down prior to painting. The CA soaking is necessary since this is Flexible Phenolic and if I sanded the outer phenolic "shell" off I would have the soft innards. . . no way, bring on the CA to harden those innards up.

For finishing, I used Red Devil Light Spackle to fill the spirals and to smooth out the fillets a bit. I then sanded that down and sprayed the entire rocket with Plasti-Kote Sandable Primer, which is an old-faithful product to me. It is thick enough to fill the minor imperfections and the spirals the remainder of the way. It also sands very easily.

Whenever finishing plastic nose cones, I sand them with 150 grit sand paper until all shine is removed. This puts a lot of small scratches in the nose cone, however, because I use Plasti-Kote Primer those scratches get filled right in. I use several thick coats directly on the nose cone seam and then sand it back until the seam is filled (notice picture is nearly finished filling). Once the seam is filled I change over to a 340-400 grit paper. I have never had nose cone paint chipping issues using this technique.

I painted the rocket with light blue paint from Walmart (at $0.98 per can, it's hard to beat additional comments about Walmart paint). Once finished, I used some dark, navy blue and painted one side of each fin. Did you know that Krylon paint is not too friendly with other paints? Well, it decided to cause a nice little crinkle effect on the fins. Some of the folks on RMR replied to my message about it and here are some of their comments:

• "By the way, Krylon is made with a very hot drying agent and has more lacquer -like properties. Anything non-krylon that was under it (unless your undercoat was Dupont imeron) sadly didn't have a chance."
• "The only time I had that happen was when I tried using Krylon Crystal Clear, over another brand of paint. And the only reason it crinkled was that I shot a heavy coat on first instead of a few light mist coats. After that, I haven't had that problem again."
• "I've never had a problem with Krylon-over-other, but I always allow my base coat to dry for at least 1 week. There is a period after laying down the base coat, usually of about 1 hour where you can top-coat with something else. After that, wait AT LEAST 1 week. I've mixed-n-matched Krylon and house brands for both Zellers and Canadian tire without problem."
• "Just to throw my two cents in - what works for me:
  
  • Krylon over Krylon primer
  • Krylon over Testors primer
  • Testors over Krylon primer
  • Testors over Testors primer
  • Testors clear over Krylon
  • Testors clear over Testors
  • Rustoleum clear over Krylon
  • Rustoleum clear over Rustoleum (way cool - even on Rustoleum Metallics!)
  • Krylon clear over NOTHING (lousy clearcoat)
  ...and I do all the bad stuff - heavy coats, don't wait for sufficient drying, etc. One note: Testors color coats interact with EVERYTHING if they're not fully dry - and I've had them take 2 weeks to fully dry. "

Overall, for CONSTRUCTION I would rate this kit 4 points. Instructions are adequate. Nice thick centering rings. Pre-Slotted body tube. The wood parts fit perfectly. Nose Cone doesn't. No decals. I would have liked to see Yank throw in a motor retention system, but I understand that most MPR/HPR kits do not. The recovery system is healthy and I look forward to seeing how it holds up.

FLIGHT/RECOVERY:

After a long delay, I have at last put The Bullet into the air. Only one time, but when I fly it again, I'll do an update.

Yank recommends the G64, G75, G80, H97, H128, H180, H220, H38, H112 and the H123. Here are the altitudes that Apogee's RockSim says it will get. Simulations are based on the actual weight of my finished Bullet which was 38 ounces. Yank indicates that the finished weight is 40 ounces.

I choose a SU G80-7 for The Bullet's first flight and it was a good choice. Getting much above 1000 feet is not a good thing for the field I fly in locally. But I'd like to fly this bird on an H when I can.

The G80 has a nice punch and even on this 2.4 pound rocket, it got off the ground quickly. The flight was stable and straight and at perfect apogee the ejection charge fired. The parachute seemed to deploy instantly, and the rocket fell fairly fast and straight. It didn't spin or sway noticeably, so it looks like this rocket-then-nosecone-then-parachute configuration does what Yank says.

I used a 29mm adaptor and taped the nozzle end of the G80 for the flight. To retain the motor and adaptor I used a 100-pound picture hanger that I bent into the shape I needed and then secured it using the T-Nuts I added to the rear centering ring. It all held nicely.

I added a Large Pratt Hobbies Nomex® Heat Shield which fit perfectly. I attached it about 10" above the body tube on the nylon strap. The shock cord and parachute fit within the Heat Shield which fully protected them!

The second flight took place about a week later and I decided to try an AT RMS F40-4. According to RockSim this would carry the rocket to about 500 feet. At ignition the rocket came off the pad at an angle and continued on this large arc. By the time ejection took place the nose cone was pointing at about 300 degrees on the same arc that it left the pad. Ejection popped the 'chute and the rocket landed with no problems. Again, I noticed how the 'chute deployed so nicely. I really like this method.

I'm thinking the lower impulse motors on this size and weight of a rocket just don't cut it. RockSim says the maximum velocity on the F40 is only 162 feet/sec, whereas, on the G80 it is 266 feet/sec. The more powerful initial thrust of the G80 most likely helps get it into the air and stable quicker. The F40 was a slow lift off and probably resulted in it "tipping" on the rod (remember I downsized to a 1/4" rod) before trajectory was straight up and down, like the rod. Just something to be cautious of. (NOTE: Yank's smallest motor recommended was the G64). I just don't think The Bullet should be flying on F's!

The only thing about recovery that would make me a bit concerned on hard flat launch fields was the descent rate. This 38 ounce rocket comes down on a 24" Rip-Stop Nylon parachute. It fell at a pretty good clip. In my launch field it is fine, but watch out desert dwellers. RockSim says it falls at 33 feet/sec.

One last thing to note about the parachute (besides that it is Hot Pink) is that it is a really slippery nylon. Yank calls it "Zero Porosity". It doesn't seem to get creased (wrinkled, yes) and hold folds which is nice considering I store my 'chutes in their respective rockets.

For FLIGHT/RECOVERY, I would rate this kit 4 1/2. This is based off of two flights, however, with the one very straight flight on the higher impulse motor, a quick deployment of the 'chute, a non-spin and non-sway descent (albeit seemingly fast) it seems to do the job. I will update this as I get a few more higher impulse flights on The Bullet.

Here is another 4" "stubby" rocket that gives nice performance on G motors for the smaller field. A G80 only takes this bird to 1000 feet. This is a nice rocket to have so that one can easily enjoy the entire flight and see it return. But on the other hand, when you're ready from some altitude the 38mm motor mount can let you go with H and I motors (note Yank does not have any "I" motors in their recommendation list). I give the kit an OVERALL rating of 4 1/2.

UPDATE 6/01: After 3 more launches, 2 on H128's and 1 on a G33 I will hold firm to my rating for Flight. In fact, the H128-Short Delay and this rocket are an excellent combination for being able to view the entire flight and still have some fairly impressive thrust. The G33 was a bust, but I don't no why, I think something went wrong with the motor. Recovery is where I would want to deduct a 1/2 of point since on my last flight the plastic bar on the nose cone snapped through allowing the cone to fall on its own. I think an alternate method of nose cone attachment (wood eye-screw, or a bold eye-screw with a washer and nut on the back side) is necessary. Food for thought when you go to construct one of these.

NARAM-43 Update (8/01): I decided to spruce The Bullet up for its trip to NARAM and so it got totally new paint job. I sanded the entire rocket down with 600 grit and then re-primed it. I then used Rustoleum's Hammered-Look Dark Green and Silver. Both cans were left over from other previous rockets. It turned out much nicer than my previous light blue/dark blue paint job, and it took care of the paint reaction that I had the first time.

I resolved the nose cone shock cord mount by using a 3/8" eye-bold and screwing it in fully to the hole in the center of the nose cone. The bolt is about 6" long so it is not going anywhere.

I flew it on the now common-for-this-rocket H128 at NARAM and it performed great. I got a very nice launch picture. One of the best for clarity and focus for the entire trip. Made a great 8x10 of it. Here are the pictures for your enjoyment (I hope).