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, radio operated, two channel event activation device for high power rocketry. Ya scallywag! Aye aye! T' WRC² is most often used as a backup recovery deployment device. Other uses for t' WRC² would include primary recovery deployment, ignition o' clustered motors or second stage motor, me bucko, operation o' photographic equipment, matey, or activation o' a trackin' agent or sound. Avast! 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, (Fig-2) and instructions. Ahoy! T' transmitter measures 8" L x 3" W x 2" H. Blimey! Avast, me proud beauty! A single 3 volt battery powers t' unit. Begad! There is no power switch on t' transmitter, ya bilge rat, thar be virtually no power consumption unless one o' t' trigger buttons is pressed. Ya scallywag! Ahoy! T' instructions suggest testin' t' voltage before each use, where 2.9 volts be t' minimum acceptable voltage. Ahoy! Aye aye! 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, arrr, so I leave it installed most o' t' time. Arrr! 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. Aye aye! Begad! and weighs 2.8 ounces without t' battery. Well, me hearties, blow me down! T' receiver board will nay fit into an airframe smaller than 4" in diameter. 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. Blimey! T' instructions do nay have any suggestions for this battery at this time. Well, blow me down! 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. Ya scallywag! Begad! 3.6 volt battery packs (Fig-4). Avast! Three full packs plus one extra cell will yield 12 volts (10 cells at 1.2 volts each). Ya scallywag! I have been lucky t' find some o' these batteries on clearance at WalMart every time I've needed some. Well, blow me down! Arrr! With me limited electronics background, me bucko, matey, settin' up a charger for this battery pack be a trial and error process. Ya scallywag! Avast, me proud beauty! I gathered up all me surplus AC adapters with a D.C. Begad! Begad! output o' at least 12 volts and chose one which seemed t' fully charge t' battery overnight. Ahoy! I connected t' battery t' t' receiver t' make sure it would power it for a least one hour, shiver me timbers, me hearties, which it did. 

For events requirin' very high current, possibly t' igniter in a second stage motor, it is recommended that t' receiver be wired for dual batteries, shiver me timbers, arrr, ya bilge rat, one for t' receiver and one dedicated t' t' output. Begad! 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. T' battery and receiver in a RC airplane are never firmly mounted in t' fuselage, 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. Ahoy! Ahoy! 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. Avast! Blimey! Aye aye! Blimey! Blimey! Blimey! That's t' beauty o' 900MHz and t' frequency hopping. Ahoy! Blimey! Begad! Blimey! Blimey! Blimey! Chances are you wouldn't have adverse affect over every frequency betwixt 902-928 MHz. Aye aye! Blimey! We did some range testin' prior t' t' Redstone shot at LDRS t' see if laminated airframes had any affect on performance. Ya scallywag! Blimey! Blimey! Blimey! There was a very 'slight' attenuation factor, matey, but we were still operatin' well within specs. Avast! Blimey! This electronics bay/airframe be full o' wiring, me hearties, aluminum brackets, all-thread, fasteners, (2) altimeters, 12V Nicad pack, ya bilge rat, and be laminated with wraps o' 5oz CARBON and 2 wraps o' 4oz GLASS."

"When triggerin' an event with t' WRC, 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). Begad! Aye aye! Each packet is on a different frequency. T' theory is that if one frequency can't make it through due t' any external interference, another one other will. Blimey! It's analogous t' stoppin' at a traffic signal and noticin' a 'dead spot' with your FM radio station. You could switch t' another station (frequency) and have perfect reception, arrr, matey, yet your original station (frequency) might be slightly 'browned out'. Well, blow me down! Included in a data packet are t' 16 bits o' your transmitter ID code. Aye aye! Ahoy! T' balance o' t' message is used for error detection and packet sync. It works like your cell phone (with it's short stub o' an antenna) which is also at 900 Mhz. Well, blow me down! High frequency 900MHz bands have very small wavelengths and thusly require very small antennas."

I have used t' WRC² successfully on two test flights. Well, blow me down! At t' Danville '99 launch, me hearties, matey, 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. T' J-390 turbo achieved an altitude o' about 2400 feet and t' drogue chute deployed via me command. When t' rocket drifted slightly past t' parkin' area, I deployed t' main chute, which resulted in a landin' about 100 yards from our car. T' second test be performed at t' Three Oaks Michigan launch in November. T' LCO described t' launch in great detail t' a very large crowd. O' all t' launches I've had, me hearties, I have never wanted one t' succeed more than this one. This time t' WRC² was used for t' primary and back up o' t' main chute. Ya scallywag! A Cannonball Works RRC² be used for t' drogue chute at apogee, with a PbP timer as t' back up. Blimey! Again, me bucko, a J-390 turbo Hybrid was used, ya bilge rat, this time in me extended Rocket RD 7.5 inch Skyraider. Aye aye! Ahoy! Two I-211's were on board t' be airstarted. Only one o' t' I's fired, matey, but t' launch was a success in every other respect. Well, blow me down! 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