Tuesday, March 11, 2008

Beer 'n' Pretzels II - mini-review

The Beer 'n' Pretzels II was a 38mm-powered odd-roc based on a huge Utz pretzels bin (obviously the 'pretzels' part of the name). Version I had a 29mm fin unit, which was re-used in another project.


Construction:
The body was made from 3" mailing tube and was set up for zipperless construction (search for 'anti-zipper' on ROL InfoCentral).

The fins were made from foam core, framed with dowels, and laminated with dry wall tape and wood glue. As you can see, this was a 'scrap' project. The fins and body were laminated with labels removed from beer bottles (hence the 'beer' part of the name). The amount of lamination increased with time. :)

The bottom of the pretzel bin was cut to fit the tube  The top of the bin was held down with a wing nut/washer attached to a piece of all-thread. The following diagram shows the configuration.  This was designed so that the plastic lid was largely non-structural.











Notches were cut in the top and bottom of the Utz bin, as well a the larger bulk plate, to allow the rod to pass.

Flight/Recovery
The first flight was on an H128.  It was a cool flight with a nice slow roll.  The second flight was on an H242. This time it abruptly went 'cruise-missile' at about 30 feet and, luckily, cleared the parking area. My theory is that the accelleration due to the faster H242 caused too much turbulence over the fins, which ceased to provide stability control. Anyway, I looked back at the sims, replaced the pretzel bin, glued the fins back on, and tried again with a Loki H144. The flight went fine but a long delay caused separation. I could have glued the fins on (again) and replaced the crunched Utz bin (again), but decided to move on. RIP