Estes - Goonball XL5
Contributed by Dick Stafford (Contributed - by Dick Stafford - 06/15/09)Brief:
Modifications: Construction:
All of the fins were roughed-out on paper until they looked right. The side fins were made from two pieces of 3/16" stock each. The two pieces touch at their leading edge and are separated by a strip of balsa in the rear. The leading edge was then sanded to a smooth point. The side fins were cut from 3/16" stock. The small fins on the cone are the small fin extensions from the SS1 kit. The kit provided two and I cut the others from the unused fin stock. The balsa-plastic joints were attached with thick CA and wood glue was used on the wood-wood joints. I attached a steel fishing leader to the top centering ring and the stock elastic cord to that. I had planned to use two chutes due to the expected weight of the nose, so a separate shock cord was provided for it. I knew I'd need a lot of nose weight so I attached the cord to an eyebolt that is embedded in a slurry of lead shot and Gorilla Glue. That way, the weight is securely attached to the recovery system. Of course, the nose weight was the last step. The bottom of the cone was removed to allow access for the nose weight installation and to provide a tad more room for the 'chute if needed. As I noted earlier, the motor mount is the stock 18mm. I was lucky to have the new RockSim 9 program with its PODS feature. This allowed me to simulate the actual design configuration. I set the nose weight based on this simulation model. With the unloaded weight sitting at about 5oz, the sim indicated a long rod was need for a stable C6 flight. So, early on, I decided to go for a reload. I got an 18mm Hobbyline case and a pack of D13-10s from ValueRockets.com. Great prices and speedy service!
Finishing:  Flight: At the 11th hour, I realized that I'd used the stock lug and decided this rocket was too heavy and unproven to fly with that. I removed at lug and epoxied on a piece of ¼" compatible launch lug material (e.g. a tube from an AeroTech First Fire igniter). I set each side fin on a stand-off and hooked up the Copperhead. The rocket flew great with some spin, which was undoubtedly the result of some imperceptible misalignment of one or more fins. After all, I built it. Ejection was just a tad late and the rocket recovered damage-free.
Summary: Flight Log
What You Can Do
|
||||||||||||||||
|
|
||||||||||||||||
