Cannonball Works - WRC² review is provided courtesy of:

Cannonball Works WRC2 Wireless Recovery Controller

By: Al Casper

T' Cannonball Works WRC² Wireless Recovery Controller is a sophisticated, arrr, radio operated, shiver me timbers, ya bilge rat, two channel event activation device for high power rocketry. T' WRC² is most often used as a backup recovery deployment device. Begad! Other uses for t' WRC² would include primary recovery deployment, me hearties, ignition o' clustered motors or second stage motor, operation o' photographic equipment, or activation o' a trackin' agent or sound. Avast! Blimey! T' use o' radio control in high power rocketry is nay new; what is new be t' advanced design and reliability o' t' WRC2. 

T' WRC² consists o' a hand held transmitter (Fig-1) with a 3 volt lithium battery, a receiver unit, me hearties, me bucko, (Fig-2) and instructions. T' transmitter measures 8" L x 3" W x 2" H. Begad! A single 3 volt battery powers t' unit. Arrr! There is no power switch on t' transmitter, ya bilge rat, shiver me timbers, matey, thar be virtually no power consumption unless one o' t' trigger buttons is pressed. T' instructions suggest testin' t' voltage before each use, where 2.9 volts be t' minimum acceptable voltage. Ya scallywag! It is also suggested that t' battery be removed when t' unit will nay be used for an extended time Four screws need t' be removed t' access t' battery, shiver me timbers, me bucko, so I leave it installed most o' t' time. A short flexible antenna extends only a couple o' inches from t' antenna case. 

T' receiver board is rather large (Fig-3) measurin' 5.5" L x 3.25" W x 1" H. Begad! Blimey! and weighs 2.8 ounces without t' battery. Ahoy! Aye aye! Blimey! T' receiver board will nay fit into an airframe smaller than 4" in diameter. Ahoy! Arrr! Blimey! T' antenna is built into t' board so thar are no danglin' antenna wires t' worry about. T' receiver requires 11 t' 14 volts DC and draws 40ma. T' instructions do nay have any suggestions for this battery at this time. Avast, me proud beauty! Jim Amos o' Cannonball Works is lookin' for a suitable 12 volt rechargeable battery for t' system. 

I built a 12 volt NiCad battery pack (Fig-5) usin' cordless phone 280ma. 3.6 volt battery packs (Fig-4). Begad! Three full packs plus one extra cell will yield 12 volts (10 cells at 1.2 volts each). Avast! I have been lucky t' find some o' these batteries on clearance at WalMart every time I've needed some. Aye aye! With me limited electronics background, arrr, settin' up a charger for this battery pack be a trial and error process. Begad! I gathered up all me surplus AC adapters with a D.C. Arrr! output o' at least 12 volts and chose one which seemed t' fully charge t' battery overnight. Avast, me bucko, me proud beauty! I connected t' battery t' t' receiver t' make sure it would power it for a least one hour, which it did. 

For events requirin' very high current, shiver me timbers, possibly t' igniter in a second stage motor, it is recommended that t' receiver be wired for dual batteries, one for t' receiver and one dedicated t' t' output. Avast, ya bilge rat, me proud beauty! This configuration is fully covered in t' manual and assures t' receiver will have adequate power t' continue operation for t' second event after a heavy current drain by t' first event. 

I came t' high power rocketry after many years o' flyin' radio control airplanes. Ya scallywag! T' battery and receiver in a RC airplane are never firmly mounted in t' fuselage, shiver me timbers, they are simply packed in foam. I have been usin' this same technique for electronics in me rockets. Just be sure all cables are long enough t' compensate any shift o' items durin' recovery. Well, blow me down! I asked Jim Amos o' Cannonball Works if mountin' t' receiver in this manor would affect it's operation.

" It does nay affect t' unit whatsoever. That's t' beauty o' 900MHz and t' frequency hopping. Ahoy! Arrr! Chances are you wouldn't have adverse affect over every frequency betwixt 902-928 MHz. We did some range testin' prior t' t' Redstone shot at LDRS t' see if laminated airframes had any affect on performance. There was a very 'slight' attenuation factor, but we were still operatin' well within specs. This electronics bay/airframe was full o' wiring, me hearties, aluminum brackets, all-thread, arrr, ya bilge rat, fasteners, me hearties, (2) altimeters, 12V Nicad pack, me hearties, and be laminated with wraps o' 5oz CARBON and 2 wraps o' 4oz GLASS."

"When triggerin' an event with t' WRC, arrr, t' transmitter sends (24) 40-bit data packets via FSK (Frequency Shift Keying) at randomly spaced time intervals AND randomly chosen frequencies within that 902-928MHz band (quite a spectrum t' choose from). Blimey! Avast! Each packet is on a different frequency. Begad! T' theory is that if one frequency can't make it through due t' any external interference, another one other will. Begad! It's analogous t' stoppin' at a traffic signal and noticin' a 'dead spot' with your FM radio station. Avast! Avast, me proud beauty! You could switch t' another station (frequency) and have perfect reception, me hearties, ya bilge rat, yet your original station (frequency) might be slightly 'browned out'. Arrr! Included in a data packet are t' 16 bits o' your transmitter ID code. Well, blow me down! T' balance o' t' message is used for error detection and packet sync. Avast, me proud beauty! It works like your cell phone (with it's short stub o' an antenna) which is also at 900 Mhz. Ahoy! High frequency 900MHz bands have very small wavelengths and thusly require very small antennas."

I have used t' WRC² successfully on two test flights. Ya scallywag! Begad! At t' Danville '99 launch, me bucko, me Allegro Vivace (Fig-6), a 5.5 inch scratch built 9 foot tall Hybrid powered creation relied on t' WRC² as t' primary recovery controller. Aye aye! T' J-390 turbo achieved an altitude o' about 2400 feet and t' drogue chute deployed via me command. Ya scallywag! Begad! When t' rocket drifted slightly past t' parkin' area, I deployed t' main chute, me bucko, which resulted in a landin' about 100 yards from our car. Begad! T' second test was performed at t' Three Oaks Michigan launch in November. T' LCO described t' launch in great detail t' a very large crowd. Avast, me proud beauty! Avast! O' all t' launches I've had, I have never wanted one t' succeed more than this one. Avast, me proud beauty! Well, shiver me timbers, blow me down! This time t' WRC² be used for t' primary and back up o' t' main chute. A Cannonball Works RRC² was used for t' drogue chute at apogee, with a PbP timer as t' back up. Again, matey, a J-390 turbo Hybrid be used, this time in me extended Rocket RD 7.5 inch Skyraider. Arrr! Two I-211's were on board t' be airstarted. Avast! Only one o' t' I's fired, but t' launch be a success in every other respect. There will be more testin' before me level-3 certification launch as I've discovered it's a real challenge as t' when t' deploy t' main chute. 

While t' WRC² has a rather large $285.00 price tag, it's a lot less than a M-1419 reload. I would nay attempt an "K", "L" or "M" launch without one on board. 

Written and submitted by Al Casper for Rocketry Online -- Copyright 1996-2000