Two-Stage Rockets

I have wanted to do a composite motor two-stage for several years. Finally, I got the idea of the Wild Eagle this fall. I had most of the materials for this build: I had built the Wild Child a few years before and I had a Mini Eagle Claw kit from the 2012 Black Friday Sale waiting to be put together.

All I needed to get the project underway was to order a dual deploy upgrade and a 7” long 38 mm coupler tube for the interstage coupler in November 2013. The basic Rocksim file came together over Thanksgiving vacation. The key to project was modifying the Wild Child to accept the interstage coupler. Surprisingly, that was accomplished as easily as I imagined by cutting out the bottom centering ring and bottom of the fins with a 1 ½” hole-saw. The only glitch was that the hole saw diameter was just a hair too small, so I enlarged the opening to fit the interstage coupler by wrapping the outside of the hole-saw with sandpaper. The Mini Eagle Claw came together easily over the Christmas vacation. Adding the dual-deploy upgrade apparently “finished” the Mini Wild Eagle. (Both the Wild Child and Mini Eagle Claw still need external fillets on the fins and some folks might like to add a paint job.)

Some enjoyable time was spent this spring soldering up two Eggtimer altimeters and an Eggfinder kit. ALL that was left was outfitting the sustainer av-bay. Getting the Eggtimer altimeter mounted to a sled with a battery, Featherweight Altimeter’s screw switch, and the wiring to fit in a 38 mm coupler tube was definitely a challenge. The altimeter and battery with sled slid in easily. Adding the tiny switch was torturous. Cris Erving was very helpful with the Eggtimer, especially choosing the settings for the airstart. Three 3 Dogs Anchors from Three Dogs Rocketry finished off the av-bay and interstage coupler nicely.

The first flight of my Mini Wild Eagle was on F120 to F29 (lit at 100 ft) from a fairly small field in the Adirondack Mountains. It was a great flight with two minor issues: The booster did not drag separate as expected and the Main deployment charge was a little too energetic. Since the sustainer motor lighting separated the booster, the booster did not coast upward. The five second delay expired with the booster 10 to 20 feet AGL. For subsequent flights, the Mini Wild Eagle will be upgraded with Eggtimer altimeter booster chute deployment in the interstage coupler