Madcow Rocketry - Sea Wolf {Kit} (K-135)

Contributed by Drake "Doc" Damerau

Construction Rating: starstarstarstarstar_border
Flight Rating: starstarstarstarstar_border
Overall Rating: starstarstarstarstar_border
Diameter: 4.00 inches
Length: 47.50 inches
Manufacturer: Madcow Rocketry
Style: Scale

Madcow Rocketry Sea Wolf

Brief:
The Madcow Rocketry Sea Wolf is a semi scale version of the Royal Navy‘s (that's British if you didn't pay attention in school) anti-ship missile Sea Wolf Missile system. This is a 38mm semi scale kit with cool features like fin plates, fin tips, and staggered fins.

Construction:
Contents:

  • ¼" 5 layer laser cut aircraft plywood
  • Nose Cone and steel eyebolt
  • Pre-slotted airframe
  • Centering Rings (3)
  • 38mm MMT
  • 8 laser cut fins
  • Laser cut fin tips and fin plates
  • Recovery eyebolt
  • Nylon shock cord
  • Nomex chute protector
  • 48" chute
  • Rail Buttons

The instructions are very easy to follow, and like Madcow's other kits, they are a breeze to build. The instructions fit on one folded page, and when you factor in the fact that a quarter of that is a picture of the rocket and the kit contents, you can see there's not much reading here. Some well illustrated and thought out pictures and a few paragraphs of info is all it takes to build this kit.

All the parts fit perfectly together. The centering rings were just slightly oversize so that a quick "wipe" with some sandpaper cleaned them up and gave them a nice snug fit. The solid through-the-wall fins make this a sturdy kit. I used epoxy on all the fins, centering rings, and motor mount tube. I used wood glue for the couplers. I don't know why, but there are two couplers and three tubes for the airframe. Perhaps it's for ease of shipping, but it didn't really affect the build.

I thought I add a section here all by itself on the CG. This is important on this kit. The long and large fins on this rocket make it necessary to pay attention to the CG. The kit calls for the CG to be 24.5" from the tip of the nose cone. Because of the fins and the nose weight needed, I decided to do a RockSim on this one. Keep in mind that the CG changes with different motors so you need to know what the largest motor you will fly will be. (Yes, none of this is new info, but this is one of those kits you need to put all this to use.) My weight after finishing (but before adding weight) was 63.5 oz. After adding nose weight, mine ended up at 81.7 oz with everything but a motor. This put the CG at 24".

I used steel weight and put it in the nose cone through a hole I drilled alongside the eye bolt hole. I then added 2oz of epoxy and placed a piece of masking tape over the hole. Placing the nose cone in an upright position made the weight and the epoxy settle to the shoulder area. This was important because epoxy will not stick to the plastic. Instead, the epoxy covers the machine screw end of the eye bolt and, when hardens, becomes a mass around the screw. This effectively secures the weight to the base of the cone and secures the eye bolt to the nose cone.

Madcow Rocketry Sea Wolf The most time consuming part of the build is the fillets. With over 280 inches of fillets, you have a chore ahead of you. The "fin plates" have an added difficulty by being a flat section of 1/8" plywood glued to a curved surface. The builder has about a 3/16" inch gap to fill at their widest point. A suggestion would be to make them out of basswood. This would allow them to be easily curved to the airframe, cost less, and save weight at the end of the rocket that needs to be lighter. It would even cut the build time.

Finishing:
I painted it with two coats of Rustoleum gray primer, followed by two coats of white, and a few coats of black on the nose cone. I then painted the fin plates in red after a long morning of masking. I guess I forgot to look at the picture because I did it wrong. I did look at the picture to finish with the trim. For that I used 3/16" Pactra black trim tape.

Construction Rating: 4 out of 5

Flight:
Don't let the ease of build fool you into thinking this is a wimpy rocket. The design and quality of the components will allow this rocket to rip off the pad on large 38mm motors. But, at only 5 lbs, it can also be lofted with a 29mm motor if you have an adapter on hand. My first flight was on a Pro 38 H153 to about 1,000 feet. I set the delay to about 8 seconds and this proved to be a little late.

Recovery:
This thing comes with a parachute, and I was happy about that. So many companies don't give you a cute these days on 4" and larger kits because, "it allows you to pick your own chute size". (I never did buy that excuse.) Well, I for one was happy to have them pick one for me.

Flight Rating: 4 out of 5

Summary:
This is not the first Madcow kit I've built, but it is the largest. The ease and simplicity of the build, the quality of the components, and the coolness of this kit will make it a durable favorite. If it appears I had fun writing this review, I had just as much building and flying it. Please, pay attention to your CG/CP relationship.

Overall Rating: 4 out of 5

Flights

Comments:

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B.U.D. (December 9, 2009)
Thank you for your review. It helped me with some things and gave me a couple of ideas. I guess the one thing I would add is I took you advice and went out and bought some basswood for the fin plates. I had done my fillets already so I modified the opening to fit over them. Also I took a piece of 220 grit sandpaper and laid it over the airframe and sanded the back side of my modified plates to get a closer fit. This seemed to work very well and they are almost flush now. Second, I rummaged through the wife's kitchen utensils and I found a small silicon dough spatula/spoon. This worked fantastically for the fillets. The epoxy won't stick to the silicon and wipes of easily with acetone. Maybe this will help some BAR such as myself.
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V.P.I. (April 11, 2010)
Great review! After reading it I ordered a Seawolf from Madcow. Another very nice kit (my third) from Madcow. Great looking rocket! I used West Systems epoxy for all the bonding and epoxy with colloidal silica for the gap filling and fillets. One pound of BBs was mixed with epoxy to weight the nose to bring the CG forward to the specified point. Even with that nose weighting, the rocket weighed in at just under 80oz total (flight ready but without the motor). On its first flight I it flew on a CTI J330 earning my L2 cert. It really shot off the pad looking much like prototype Seawolf launches I've seen in videos.
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John Budnella (August 6, 2012)

Update on my Seawolf from B.U.D 2009. I used Rocsim and I came up with about 22 oz of shot in the nose. I used great stuff expandable foam to hold it in place.

I certified Level 1 & 2 with the rocket, (1 on a CTI H225 and 2 on a CTI J330). Between the cert flights I had a few others and was having difficulty getting the delay right. I found that 8 secs was about right. I also had problems with zippering (delays to long). I finally repaced the first 6 inches of tube with Blue tube and have not had any more problems since. The rocket flies great especially on I800 Vmax and gets a reaction from the crowd everytime.

It is a good starter kit for someone wanting a sturdy rocket to learn on.

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Keith Christ (April 22, 2017)

What size 29mm motor would you suggest. I was told by apogee not

to  it with a 29mm.

thanks, Keith

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Bill Berger (July 2, 2017)

@KC

I do not have this kit (just looking at purchasing), so the following is not from actual experience. As long as you don't build this thing crazy heavy, any of the higher thrust 29mm H motors should work nicely with this rocket. Due to the large fins, I would look at something with a pretty good kick off of the pad. Especially if there is any wind. From Aerotech, the H268R and H250G both have a nice 300 newton punch at the front of the thrust curve. However, the H210R, H220T and H238T might also work. I would avoid any of the lower thrust / longer burn motors myself. I would suggest getting Open Rocket (FREE) and running a couple sims with the actual data from your build to confirm selection. As the OP stated, this is one of those rockets where you just you need to really be conscious of checking your stability and there can be great discrepency in the finished weight due to construction. Good Luck!

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