Will's Cert 3 electronics subsystem

The dual-deploy electronics system consists of two indentical, independent, systems running in parallel. Each uses a single MissileWorks RRC2 barometric altimeter. Power to each altimeter is controlled by its own MissileWorks rotary switch. The two switches are accessed through the payload bay vent.

The rotary switch has two different positions: 110V position
2 3
| |
1 4
220V position
1 4

Pins one and two are wired to the altimeter switch connector. This means the altimeter is powered on when the switch is in the 110V position.

RRC2 connectors are:

All wiring is 20-gauge stranded "speaker wire" with soldered ends. "Euro style" screw terminals on each bulkhead are used to connect the e-match leads.

The altimeters are configured identically with these switch settings:
Switch numberSettingFunctionBeep pattern
1on=1J2 at 1000'short
2off=0dual deploylong
3off=0No Mach inhibitlong
4off=0No Mach inhibitlong
5off=0J2 at 1000'long

Vent Hole Sizing

The avionics bay for this kit is about 9.5" in diameter and 9" long. This is a volume of about 637 cubic inches. I made a 0.5 inch hole to serve as the equalization port and to allow access to the altimeter power switches. The MissileWorks manual suggests an inch of port diameter per 400 cubic inches. This equates to a payload bay volume of 200 cubic inches. I will put a foam block of about 437 cubic inches (7.5" per side) into the payload compartment to get down to the desired total volume.

Last revised 2005-10-24.

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