Today's Featured ReviewOverall Rating:  Contributed by Christopher M. Cain Two weeks ago I got a sneak peak of Giant Leap Rocketry's new kit, the Mariah 38. Just like the front page of the instructions indicate, it is an extreme altitude kit. The first time Ed showed me pictures of this kit I knew I had to have one. The Mariah 38 is only 17oz and will take an Aerotech 38/1080 case or a CTI pro38 6gxl case. It is 44.75” long and a 38mm minimum diameter kit made with their magna-frame airframe. It also has a set of .062 fins that are very easy on the eyes. The leading edge is a long pair of sweeping arcs that, when combined with the 38mm pinnacle nosecone, looks like it’s screaming while sitting still. In fact, the first time I saw a picture my eyes were drawn to the blue and silver and I immediately thought of Larry Dixon Jr.’s Miller Light dragster.
Ed and Kent both kept telling me the Mariah is a straight forward kit - on the outside. My first look at the kit’s parts and 24-page instruction book left me extremely excited. Who says you have to deploy a main at Apogee with a minimum diameter rocket when you want to keep it short and only have one separation point in the airframe? The Mariah solves the problem of how to go drogue-less and then deploy a main at a typical dual deploy altitude: a breadbox avbay and shotgun tube! The giant leap shotgun deployment system is an innovative concept because everything stays attached from launch until landing. No more dual deployment from one end of an airframe, forcing you to chase two or more parts. Everything stays attached with Kevlar and at apogee deployment there is no way to accidentally deploy the main chute - except for operator error.
The breadbox avbay is a very simple way of installing an altimeter in a rocket. Wiring it is tool and hardware free. It has a cover that slides open and shut just like the old breadbox on Grandma’s kitchen counter. It is the fastest way to set up an avbay that I have seen so far; no sled, no all-thread or screws. Just wire your altimeter with a battery and e-matches and you’re ready to go. The only difficult part of the setup is deciding how to safe your altimeter.
A word of warning to the wise: READ AND UNDERSTAND THE INSTRUCTIONS FIRST!You have to build this kit step-by-step and word-for-word. If you rush into the Mariah or skip around in your assembly there is a good chance you will wind up with a display model. There are parts on the breadbox avbay that must stay free of ca and epoxy. On the other end of the model is another cool addition called the supermount. It is the same general idea as the hardpoint shock cord mount, but it is lighter and takes up much less room in the airframe. A word of warning here, too: if you get epoxy dripping one way you won’t be able to fully install a long 38mm motor. Get epoxy dripping in the other direction and you won’t be able to get the shotgun deployment assembly installed for flight.
In the Mariah kit you have two choices: rail guides or tower.I built mine with the acme rail guides just for the ease of not having to drag around a tower for flight. After I installed my rail guides, I airfoiled the fins by hand on the leading and trailing edges. G10 is not fun to airfoil by hand but trust me, it is well worth the time. These fins are pretty!
After I finished that step, I scuffed up the magna-frame around the fin dados slots and cut out my fin guide. The instructions recommend using JB Weld to attach the fins and a drop of ca on each end of the fin root. This creates a very strong joint. As a matter of fact, the joint will be the last thing to fail when you use this attachment method. Regardless, reinforcing the fin joints with the included fiberglass cloth is still recommended. I prefer to tip-to-tip glass the fins on my rockets because it is easier to blend and finish, but this time I tried using strips from the airframe to the fin just to reduce weight. I don’t know if I would try it again because of the extra sanding that is required to finish them, but it was certainly worth a try.
Finishing is pretty straight forward. I have heard of all kinds of ways to fill spirals in airframes but my preferred method is Crawford’s vinyl spackling, which can be found at most home paint stores. It dries fast, is smooth and practically glides on when it is applied, and is a dream to sand. After I filled and smoothed the spirals, I primed my Mariah with Duplicolor grey high build automotive primer. After many hours of wet sanding I have no idea how I should paint it. Just like a hot rod, the curves make the Mariah 38 scream for pearls, candies, and metallic finishes.
Unfortunately, I have yet to find the opportunity to fly my Mariah, but it was a lot of fun to build. It made me remember there is always another way to do something, to improve and advance from what has already been proven. The shotgun deployment is definitely a unique setup where the hardest step in flight prep is trying to fold up the thin mill nylon parachute. It is by far the slickest nylon chute I have ever handled, but if packed correctly in the shotgun tube main deployment shouldn’t ever be an issue.
Overall, I would recommend this kit to any advanced flier who wants something different. If you have the speed and altitude sickness like I do, then this is the kit for you. I was lucky enough to see the prototype fly on an Aerotech J570w and it was awe inspiring. My two recommendations for flight would be to stand way back and most importantly, DON’T BLINK! You will see the motor light on the pad and then you will see burnout and the tracking smoke start a few thousand feet above your head. The Mariah 38 is perfect for low thrusting long burn motors and I plan to fly mine on an Aerotech I59wn. I just wish that we had more long burn motor choices in the 38mm range. As I said before, whether you’re addicted to speed or to altitude, the Mariah 38 is the kit for you. At the introductory price of $79.95 it’s a deal. Especially when you consider the amount of work that goes into making the parts for this kit. Your biggest decisions will be if you are going to use the provided acme rail guides or a tower, whether or not to add a slimline instead of friction fitting the motor, and finally…do you really wanna buy just one?
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