Brief:
The Corona-2 is a separate kit that compliments the FlisKits Corona creating a 2-stage rocket. What also makes this stand out is that it takes the tube fin design of the Corona one step further.

Construction:
Before starting the Corona-2, you must have a built FlisKits Corona kit. If you built your Corona with the motor retention clip, you will need to cut it off the rocket so that you can direct stage the motors in the Corona and Corona-2.

The kit contains:

• 3 laser cut plywood fins
• 1 BT-70 ring
• 1 BT-101 ring
• 1 BT-50 body tube
• 1 BT-20 motor tube
• 2 CR5020 centering rings
• 1 BT-50 coupler
• Instruction manual

The instructions are very simple. First, you must have a fully built FlisKits Corona kit as it is needed to place the forward (smaller) ring and align the 3 fins.

The motor mount is typical LPR: a couple of centering rings with a motor tube glued together and then inside the larger body tube. That is followed by a coupler glued halfway into the forward end of the body tube to connect to the Corona kit.

That assembly is slid into the aft end of the Corona. The small ring is slid around the Corona's ring fin and taped into place to keep it from moving. Lines are drawn on the Corona-2 body tube to match the fins of the Corona. The perfectly cut plywood fins are glued onto the body tube and forward ring with plenty of attention needed to ensure that they are lined up with the Corona's fins. Once all of the fins are dry, fillets are applied.

The last step is to glue and fillet the BT-101 ring onto the fins.

Finishing:
Filling the grain of the fins was arguably the most difficult part of the entire build--and it wasn't even that hard. It merely required patience more than anything. I used diluted Elmer's Fill 'n' Finish along with an epoxy spreader to help press the filler into the grain of the wood while also wiping away as much excess as possible (and reduce the amount of sanding I needed to do!) I sanded the fins smooth with 320 grit sandpaper.

Painting was less of a challenge than I originally anticipated. I was concerned about getting overspray on the coupler or inside the motor mount as well as potential runs when trying to paint the inside of the large aft ring fin. [NOTE: You do not want to paint the inside of the forward ring as this may cause the overall fit to be too snug when attaching the stages together!] My fears turned out to be unfounded--or maybe I just plain got lucky! A couple coats of Krylon white primer with some light sanding in between followed by Krylon Sun Yellow Gloss had it matched up perfectly with the paint job on the Corona. I added some silver automotive pinstriping tape as an accent.

Construction Rating: 5 out of 5

Flight:
The Corona-2 was mated up with my fully prepped Corona. Using clear tape, a C6-0 was mated up with a C6-7. A little masking tape was needed on each motor to make sure that neither would kick undesirably. With the motors loaded up in the rocket, I set it up on the pad.

It left the pad with plenty of thrust pushing the rocket up to about 400 feet before successfully staging the Corona sustainer. The Corona is a very sleek rocket so it got some altitude when staged C6 to C6! Don't try this on a small field. I pushed the limits of the schoolyard I was at causing the sustainer to drift on the way down across the street into some neighboring woods. Thankfully the sustainer didn't get caught up in a tree and was recovered successfully.

Recovery:
The Corona-2 booster has a tumble recovery typical of BP staged designs. It backflipped all the way down (much like the CD spool rockets I have built) to land safely within 40 feet of the pad.

Flight Rating: 5 out of 5

Summary:
The already unique FlisKits Corona kit is definitely enhanced by the very complimentary design of the Corona-2 booster. I dig tube fin and ring fin rockets so what could be cooler than a 2-stage ring fin design?!? Any existing Corona owners can add the Corona-2 to their fleet after modifying the Corona's motor clip. If staging with a pair of C6 motors though, be sure to have plenty of room at your launch site!

Overall Rating: 5 out of 5

Brief:
The Corona II is perhaps the sleekest, best looking futuristic staged rocket I know. In the summer of 2005, I learned that FlisKits was developing this kit, and immediately inquired about one after reading Lance's preview on EMRR. Finally, in February 2006, the model was on the market and I snapped up one of the first kits.

Construction:
Lance's review covers the basics of assembly and finishing. I will just add a few personal views.

The components are typical good Fliskits quality. The tubes have very minimal spirals to fill. The chute is typical Estes-style plastic and thread. I hate chute failures so I upgraded to one from my stash of stuff.

The body tube is BT-50 size, so the rocket is long and skinny. To avoid having to fuss with wadding in the narrow tube, I purchased a BT-50 baffle from FlisKits. I got a nice email from Jim Flis suggesting the correct baffle size and the recommended placement (it should replace the tube coupler halfway up the 1st stage body). Thus, my box arrived with three separate packaged kits (Corona kit, 2nd-stage kit, and baffle kit) and three sets of instructions. The instructions were all very clear and the first stage directions give explicit steps for building for use with the second stage portion.

This kit had laser cut fins that provided an amazingly precise fit, even surpassing the renowned fit of Edmonds Aerospace kits. The fins and tubes fit together so perfectly, there was almost no seam visible when dry fitting. It is virtually impossible to make a mistake or misalignment because of this precision.

Needless to say, I did make a mistake. When dry fitting the outside stage 2 fins, I forgot to include the coupling ring that slips over stage 1 to connect stage 2. Thus, my fins appeared to leave a slight gap. So I removed about 1/16" from each and prepared to glue. At this point I had positioned the coupling ring and realized my error. The visual effect of my error was to break the straight line formed by the edges of the 1st and 2nd stage fins and to leave a gap at the seams. I corrected this with another bit of fin trimming, and if you look closely at my photo you can see I recovered the intended visual look, but slightly differently than the original. This mistake was due entirely my own carelessness.

PROs: Absolutely flawless precision fit of quality parts.

CONs: None whatsoever.

Finishing:
Detailed painting is a bit tricky, especially inside the 1st stage ring area. And a kit this cool deserves a nice paint job. So I painted the body black and then brush-painted the fins and tubefins for a pleasing effect. Clear gloss spray went over everything.

Construction Rating: 5 out of 5

Flight:
The first flight was on a B6-0/C6-7. The Corona II shot off the pad and when the sustainer lit, I knew I'd be lucky to find it again. The booster tumbled safely down, and the sustainer vanished into the stratosphere. We saw the ejection smoke, and by walking in a straight line past the booster landing site, we eventually found the sustainer. A second flight on the same motors was similar, but a fin on the booster stage separated from the tube and the ring after the booster sort of glided down (no tumble) from a hard impact. This was easily repaired.

Some months later after fixing my goof with the baffle, we flew it again on B6-0/C6-7. Alas, the sustainer went unstable after separation. It was not because of the shortened length--it was because the body tube had slipped while the repair glue was drying. I had made the repair slightly off kilter. In my defense, alignment was a bit trickier then with the tail ring on, but I should have rolled the tubes on a desk with the tail hanging off then supported the rocket underneath to prevent slippage while the glue dried.

Recovery:
The BAF-50 baffle is great. The chute hasn't had the slightest bit of scorching. However, this upgrade came back to bite me. While prepping for a later flight, I subconsciously added wadding before remembering it was unnecessary because of the baffle. Instead of simply leaving it there, I stupidly tried to shake it out. I ended up crimping the main body tube and had to cut out 1.5 inches to repair the damage, inserting a coupler. True to form, Jim Flis responded within minutes on the The Rocketry Forum when I posted an inquiry to confirm the rocket would remain stable after my fix.

Flight Rating: 4 ½ out of 5

Summary:
Corona II is a very nice rocket and I'll be sad if it is retired so young. I'll probably make another attempt at more careful repairs and fly again.

PROs: Sleek, fast, high, and easy stage separation.

CONs: Booster may not always tumble well, and be careful not to lose this rocket with extra high motor combos!

Overall Rating: 4 ½ out of 5