Brief:
The Hydra 7 is a currently the "newest" kit by Semroc Astronautics (originally released in 1969 and re-released on January 1st, 2004). The rocket is based around six 18mm motor tubes and is a great clustered, high altitude payloader, and retails for $23. The rocket can fly on anything from 1 C6-3 to 3 C6-5s to 7 C6-7s. With its largest motor setup (7 C6's) it is supposed to reach 1700'. For recovery it splits into two sections, the payload comes down under one 12" parachute, and the booster on two 12" parachutes.

Construction:
All parts came packaged in a large plastic bag, with the smaller ones being inside their own small bag. All parts were in excellent condition and all present.

Parts List:

• 2 Body Tubes 1.69"
• 7 Body Tubes 0.79"
• 1 Body Tube 3.63"
• 1 Nose Cone 1.631"
• 3 Nose Cones 0.714"
• 4 Laser Cut fin sheets
• 1 Balsa Tube Coupler for 1.69" Tube
• 1 Launch Lug 1/8"
• 1 Screw eye
• 2 Elastic Shock cords
• 1 Kevlar® Shock cord
• 3 Parachutes 12"
• 3 Sets of shroud lines
• 1 Wooden dowel 3/16"
• 7 Thrust rings
• 6 Plugs for thrust rings
• 1 Decal Sheet
• 1 Engine spacing tube
• 1 Q-Tip for glue application

Construction starts with sealing the fins, because there are so many it would be hard to reach them after the rocket is finished. I used about 3 coats (on each side) of some type of spray-on sealer, although I'm not sure what brand it is. Next, you glue together the 7 motor tubes in a six-point star pattern. From here, you attach the 6 shroud support fins in between the joints of the motor tubes (LOC Viper style). Then you glue on the shroud and put in the motor blocks. The six outside blocks are plugged with cardboard disks, and the central one is left open for the ejection charge to go through. The next step is where the rocket begins to get its unique appearance. From the outside, the nosecones in the kit appear to go halfway through the body tube. However, instead of cutting the body tube, you are supplied with 3 nose cones. You have to cut each one in half and then sand the curvature of the 1.6" tube into the side of them so they conform to the body tube. I thought this step would be the trickiest of them all, however, it was quite easy. First I cut the Nosecones in half with a microsaw, then I used a drum out of a drum sander to sand down the curve on the nosecones. Once you get that done, you test fit them into the booster tubes and slide the Main body tube down onto them. You are supposed to re-sand if necessary but I didn't have to. The next few steps involve gluing on the fins, which I'm sure everyone here knows how to do just fine. The only little catch with the fins is that...there are 21 of them! (And thank goodness they were all laser-cut!) After that is done, you assemble the payload section (glue in coupler and screw eye), and the other little things you do at the end like fillets, launch lug, etc. Construction was pretty fun, and I liked the way that everything fit almost perfectly.

Picture courtesy of SemRoc        

Finishing:
For finishing, I first sprayed the entire rocket with white primer. I then touched up rough spots with sanding and putty until when I primed it everything was smooth and filled in (spiral, balsa grain, fillets, etc.). I then sprayed the entire rocket with white gloss Krylon paint. When that was dry, I sprayed the payload tube and nose cone Krylon gloss blue. After that was dry, I applied 4 of the many decals the rocket comes with.

Construction Rating: 5 out of 5

Flight:
At long last, I finally got to fly it! Last month's launch was cancelled due to snow, so I had been waiting anxiously for this month.

First flight was with only one C6-3 just to test things out. Worked nicely, with a slow, majestic ascent.

Second flight was with seven C6-7s.

First attempt: Wired up 7 high current igniters to the motor and twisted the wires together. 5-4-3-2-1-Lauch...nothing. Too little current coming from the launch controller.

Second attempt: Same igniters and setup, but used leads from the high-powered pads. Still no go.

Third attempt: Took out 3 motors to have a 4 motor cluster. Used leads from high-powered pads. 5-4-3-2-1-Launch...Smoke...nothing. Igniters in all 4 motors burned but not the motors. The igniter plugs seemed to have insulated some of the current because only the lower-most part of the igniter had burned and the pyrogen was still intact on the upper portion--the motor touching portion.

Fourth attempt: Used a clip whip (Thanks to Dave Morey for supplying it) to wire up 7 Estes igniters. 5-4-3-2-1-Launch....Smoke....FIRE!!! The rocket roared up into the sky with the full fury of 7 C6 motors burning in the rear. After about 3 seconds, with the rocket barely in sight, POP! POP! POP! POP! POP! POP! As the 6 outboard motors were ejected. The central motor ejected the parachutes and it drifted about 1/2 mile downwind. Post-flight inspection showed that all motors had apparently burned, because all of the motors ejected.

PROs: Full cluster ignition is incredible to watch. Attracts a lot of attention on the pad.

CONs: Hard to light all motors, especially with high-current igniters. The only igniters I found that would work are Estes Solars, but for those you need a clip whip because the wires aren't long enough to twist together.

Recovery:
First Flight (1x C6-3): Loosened one fin on impact, but that was my fault, because I only attached one of the parachutes to the booster section. Fin was easily fixed with some CA glue and accelerator.

Second Flight (7x C6-7): If you ever fly this rocket on the full load-out of motors, you may want to consider tying the two sections together or installing a micro dual-deployment device because this rocket DRIFTS! I had to walk about 1/2 mile for the booster and then the payload was another 1/2 mile past that. Whew! I'm glad I didn't put the two parachutes on the booster for that flight! Anyway, the same fin loosened again at the fillet, but that can still be repaired.

PROS: Recovery device is well made and anchored well. Provides an okay decent rate.

CONS: Drifts very far even without one of the three parachutes.

Flight Rating: 4 out of 5

Summary:
Overall, I really enjoyed this rocket in building and flying. The only thing that needs a little work is the recovery system. If you buy it you will not regret it and you will have a lot of fun with it. Currently this is my favorite rocket out of a fleet of about 20.

Overall Rating: 5 out of 5

Brief:
Semroc Hydra-VII is a 7 motor cluster rocket with a futuristic design.

Construction:
The kit included every part that was described in the long list. There is a very nice exploded view of the rocket in the instruction sheet that helps in identifying the wide array of parts, along with 3 sheets of very nice laser-cut balsa fins and a host of tubes and several nosecones. The kit comes with some plastic parachutes that require assembly. All of the hardware seemed to be complete and adequate. The step-by-step instructions are clearly illustrated and complete.

I built the rocket according to instructions, using all shock cord, screw eyes, etc. that came with it. The construction process involves assembly of the big, complicated-looking rear section consisting of a big ring fin (referred to in the instructions as an augmenter shroud) with a host of small radial fins both at the interior and exterior of this ring. The fins were very easy to deal with. The instructions suggested sanding them to size at a couple of appropriate points. The instructions suggest appropriate fin-alignment markings and alignment techniques, making the fin assembly straightforward throughout. The instructions suggested yellow glue for the fins. I used medium CA to securely tack all fins in place and then added very limited yellow glue fillets throughout. In many places I had difficulty adding fillets because my fingers are too big to fit into many of the narrow inner fin spaces.

The instructions begin with an extensive description of the assembly of the 7 parallel motor tubes. The description is I think overly laborious but is clear and does a good job of insuring that the foundation of the rocket is secure and correct. The interior fins are slotted between the 6 motor tubes that surround a central motor tube (all motors are 18mm). The big ring fin fit over the inner fins like a charm after sanding the edges of the inner fins a bit. I made this fit too tight at first during a dry fit, resulting in some obviously bent, overstressed inner fins. I removed the big ring and performed the aforementioned sanding of the inner fins resulting in a tight but gentle fit. When gluing the big ring in place, I pressed it aft, onto the table, making the rear edge of the ring flush with the aft end of the motor tubes. I then realized that this was not according to the design. I noticed that the rear edge of the inner fins sweep forward about half and inch. This fine point was not easily seen in the otherwise very detailed drawings in the instruction manual but is something that an experienced builder should have picked up on. The ring was meant to be installed so that its rear edge is flush with the rear edge of the inner fins, not the rear end of the motor tubes. I could not reverse this step, so I continued on, reasoning that this flaw would not be detrimental to flight and that the rocket would look nearly as intended. Addition of all exterior fins was quickly done with CA and went without a hitch.

The 7 motor tubes all butt up forward to a large body tube. The 6 outer motor tubes each get half of a nose cone, creating the cool nubbly transition from the rear motor assembly to the single large body tube up front. The balsa nosecones must be cut in half and sanded to fit. I used my small belt sander to aid in this process and got a pretty good fit all around with the judicious addition of some masking tape here and there. I think that assembly of these nosecones pushes the skill level of this kit beyond the reach of a beginner but makes it suitable for someone wanting a significant challenge. Assembly of the long, beefy front tubes and nosecone is straightforward. The instructions suggest plugging all but the central motor tube. I left 3 additional tubes open to allow for motor ejection, in case all motors do not light. This needs to be considered carefully when preparing for flight.

During construction of the rocket, it occurred to me that finishing the rocket with anything close to the recommended color scheme was going to be extremely difficult due to the intricate nature of the rear assembly. I decided early on that I would have to dream up some simpler paint scheme especially since I don't like to spend much time painting my rockets. Masking off detailed areas of the rocket would obviously be very difficult. Sanding the details was going to be a challenge as well.

PROs: The instructions are detailed and well illustrated. The parts are all good quality, especially the fins.

CONs: I messed up the position of the augmenter shroud and the instructions might provide slightly more detail emphasizing the intended construction method here. In the end though, it was I who slipped up. Assembly of the plastic chutes is probably not worth the effort. I substituted some preassembled chutes that I had on hand.

Finishing:
By the time I completed construction, it occurred to me that I am not particularly enamored with futuristic design model rockets. I admitted to myself that I chose this kit because of the 7 motor cluster flying challenge, not because of the futuristic design. Thus, I decided that I would not go to the trouble of carefully sanding details and hand painting all of the fins according to the manufacturer's recommendations. I wanted to be able to mask off large areas and spray the rocket, thus I proceeded to mask off things in a generally concentric fashion and sprayed it red, black, and silver. I decided not to apply the decals since I did not count this paint job among my best. If my son decides to repaint it, he can apply the decals at that time. My enthusiasm for the rocket was flagging considerably as I imagined the effort that it would take to do justice to the design with a perfect paint job.

PROs: The tubes and fins hold paint just fine and minimal sanding was required before I gave it a rather poor paint job.

CONs: I am not fond of the detailed painting required. If I were to redesign the instruction sheet for this rocket, I would suggest that all fins, tubes, and nosecones be painted before assembly. This would actually be very straightforward and would not interfere with assembly, providing even the most unenthusiastic painter the chance to finish the rocket in near-archetypal fashion.

Construction Rating: 3 ½ out of 5

Flight:
For the first flight, I used 4 C6-5 motors. Rocksim puts this at about 1200 feet. It think that might be a bit higher than it actually flew. All 4 motors ignited and the boost was straight and nice. The boost was a bit slower than I expected, which gave it just a little bit of a majestic look to the takeoff. All motors fired their ejection charges. The upper section recovered fine on a 12-inch ASP mylar chute (a bit too much chute for the upper part), but the lower part had troubles. The rocket came down like a perfect inbound missile and lawn darted rather badly. The 18-inch plastic chute that I had intended to recover the heavy lower section of the rocket was melted into a blob, hence the poor recovery. Perhaps I forgot to install recovery wadding? I just cannot remember... I did not notice any wadding fly out at deployment, but I also might not have been paying that much attention either. The main body tube is a complete loss, but all of the small nosecones and all parts aft of the transition appear to be in perfect condition, so I think that I can rebuild it fairly easily. I suspect that upon rebuilding this rocket will take on a new character and may get bashed into something unusual--requiring a new paint job, of course.

Recovery:
I installed the recovery system as suggested and I think that it is adequate.

PROs: Nice boost, very stable flight (even when coming down without the front section). Clusters are cool.

CONs: None, other than the problems I caused myself. Also, I would prefer to recover the rocket in a single piece rather than according to its current two-part design.

Flight Rating: 4 ½ out of 5

Summary:
The Semroc Hydra-VII has the look of a complex, futuristic design rocket that flies with a 7-motor cluster (7 x 18mm) and recovers in 2 pieces. I purchased the rocket in order to experience the cluster flights and only during construction and finishing did I admit to myself that the futuristic rocket design does not hold a special place in my heart despite having grown up around a variety of such groundbreaking designs (like the Mars Snooper). I just do not recall having ever been drawn to the sci-fi aspect of model building. I am thus not a good judge of Semroc's entry into the retro design and clone arena. I think that they have done a very good job assembling a kit from quality parts and they have simplified the assembly of this complex kit. I have a couple of other kits from Semroc, but I will skip building their other futuristic design kit, the Laser-X, since I probably would not do it justice.

Overall Rating: 4 out of 5