Cherokee 3 DD

I won a Hawks Hobby Cherokee 3D in a contest in late 2006, and began work on it soon after. It was nearly complete after the Christmas season needing just a bit more paint.

Then the rain came, and the humidity. There might have been an hour or two that were suitable for painting that winter and spring, but they were few and far between, so the rocket sat on the bench collecting dust and waiting for better weather and owner interest. I kept hoping for a dry spell, but 2007 was a very wet year in the Dallas-Forth Worth area.

I finally got going on it again this season and painted the upper airframe. The decals went on last night (Leap Day), and it looks great.

Key changes to the basic kit include splitting it in two for dual deployment (hence the name change) and fiberglassing the fin section.

The rocket uses a 2.34" airframe tube which slip fits over BT-70 quite nicely. Thus, with a BT-70 insert, it was a perfect match for my BT-70 interchangeable motor mount system. Options are many, but with the added weight of the motor system and fiberglassed fin section, the rocket came out heavy, so it will need F and G impulse for decent flights. Thus the 1x29mm and the 3x24mm will be the main woosh makers.

With the interchangeable motor mounts, the internal fin tabs had to be removed. Therefore it was very important to add external structural fin fillets and fiberglass to compensate for the change.

The extra long coupler doubles as the electronics bay. The forward airframe is attached to the coupler by screws. At apogee, the altimeter separates the rocket into two tethered sections. The main even blows the chute out with the nosecone.

Here is shown the switch section which slides into, and will be hidden in, the lower airframe. The center screw switch engages the altimeter power while the upper and lower slide switches connect the main and apogee (lower) charges.

One idea under consideration is to have an alternate coupler which would allow motor deployment. This might be handy for use with the stock 3D power.

Other modifcations included some glass around the opening of the forward airframe. This helps to cut the shear pins holding the nosecone in place and protects the airframe from being damaged by the pins.

Here's great liftoff shot of the Cherokee 3DD on its first flight.

Photo courtesy of Bill Gee

12-29-2008