The FlippiFin is a unique design that uses a surplus spring-loaded military flare fincan. When loaded into its launch tube, the curved fins are flat against the body. When the rocket exits the tube, the springs pop the fins out, providing stabilization.
Picture courtesy of Aerocon
Most of the parts for the FlippiFin are your standard rocket fare: a body tube, plastic nosecone, shock cord material, parachute and centering rings. In keeping with Aerocon's large line of surplus military equipment, the included parachute is a surplus olive drab X-form. The most important component, of course, is the spring-loaded fincan, which gives the FlippiFin its name. Due to the weight of the fincan, the necessary 2.6oz of noseweight required to keep the rocket stable is also included. Rather than the elastic we see in some kits, the FlippiFin's shock cord comes in two parts. The first is a thin Kevlar® cord which is used to provide an anchor to a tab on the fincan. This cord is small enough in diameter that, if used alone, it would easily zipper the body tube. To prevent this, the exposed portion of the shock cord is a much wider length of different material which will help protect the body tube.
Assembly of the FlippiFin is very straightforward, with no real surprises. A bit of trial and error is required in fitting the fincan, due to its nonstandard dimensions. To install the fincan, masking tape is used to create centering rings on the motor mount. Since no two brands of masking tape are exactly identical in thickness, the instructions give an approximation on the number of wraps required. I found that I had to remove some of the tape in order to get a good fit. Since the actual mounting rings on the fincan are only about 1/8" wide, after achieving the proper thickness, I used an X-acto knife to trim their width down so the tape is completely hidden by the fincan. Once the tape rings are properly sized, the single most critical aspect of the construction is next -- gluing the fincan in place with thin CA. Here, the instructions state to make sure the fins still open after gluing. The implied warning isn't nearly strong enough! It took 3 seconds of CA work to render my fincan inoperative. It took 3 HOURS of work to clean the CA out of the hingset. On my second attempt, I used a bottle of CA with a small (approx 1mm) applicator extension tip, which allowed very fine control of the CA. With the extension tip, I got sufficient CA wicked into the tape to harden those, as well as enough to form a good solid bond between the fincan and the tape. And, most importantly, my fincan works as it should! I plan on suggesting to Aerocon that they recommend the use of an extension tip in their instructions.
The metal fincan on the FlippiFin introduces an extra challenge in painting. Applying paint to the fincan would have the same effect as getting CA into the hingset and springs -- the fincan would no longer operate. Because of this, the fincan is best masked off for spray-painting, and any finishing of the fincan area should be done by hand. The instructions recommend using a Sharpie-type black marker to color in the motor mount tube that is visible between the opened fins. Careful application of paint with a small paintbrush would work as well, and would allow for more color options.
Construction Rating: 4 out of 5
Since spring flying season is just starting here in Nebraska, I've only had one opportunity to launch my FlippiFin, at our most recent high-power launch. Launch opportunities for the FlippiFin will be limited in general, due to the metal fincan. The instructions explicitly state that this rocket is not approved for use at NAR launches, so plan accordingly! The instructions list three motors, only two of which I listed in this review. The D12 is listed as a "marginal" flight, due to rocket weight. When the vendor lists a motor as "marginal", to me, that means "don't use it!" The other two motors are single-use Aerotech motors, while all the 24mm motors I buy are RMS, so I decided to go that route, instead, and made use of an F39 I had available. Preparation of the rocket is no different than most others. A small handful of cellulose insulation, followed by the parachute and shock cord, then the nosecone. The 24mm RMS motor was given a TIGHT friction fit with a bit of masking tape, to make sure I got my casing back, and everything was just about ready to go. Igniter installation gains a slightly different twist, due to the tube launcher. The igniter is installed in the motor, the breech plug removed from the tube, and the rocket slid in. The igniter leads must then pass out a small opening right above the breech plug, then the plug can be reinstalled. The tube launcher itself has a launch lug, to allow a standard rod to hold the launcher vertical. This is placed on the pad, and the exposed igniter leads hooked up. On the F39 I've used thus far, the rocket literally EXPLODES from the tube. The effect is incredibly, and everyone jumped, due to the noise. One club member who was about 150 yards off, recovering one of his own rockets, though it was a CATO, instead of a launch!
Having misplaced the original parachute, I substituted another parachute of approximately the same size. Recovery was perfect, with nary a ding on the rocket. The rear of the rocket, does have some minor black markings, due to the rocket exhaust being contained by the tube launcher, something the instructions mention will happen.
Flight Rating: 5 out of 5
The only true detraction to the FlippiFin is the limit that some people will experience in launch opportunities for this rocket. If your local club is a NAR club, and you only have opportunities to fly under their rules, the FlippiFin is not for you. If you hold private launches, or have a local Tripoli prefect, then this is a fun little rocket! The metal fincan and tube launcher makes for a unique, but safe, addition to a launch. While some may feel the metal fincan makes the rocket "unsafe", I feel it is no less safe than the G10 fins we see on some similar-sized rockets.
Overall Rating: 5 out of 5