Radio Control: Electrics

RADIO CONTROL ELECTRICS -iiu J 1 *UfL1U -qu1 i F1U MONTHS topics include meet announcement new catalog observations 98 LVRCS meet servo current drain related consequences own ESC design progress Concord Model Engineers conjuction Sailplane Electric Modeler present Third Annual Devil Mountain Electric RC Fun Fly Sunday October 4 meet will held Bay Area Radio Control Society field Richmond CA Described totally informal event meet includes raffle several fun events including AULD some unusual creative Pylon races models really fast pilots choice award Contact Chuck Hill 1382 Deerfield Court Concord CA 94521 Tel 925 685-1546 Greg Gallegos 925 684-9268 New Creations RC has released latest version its Electric catalogissue 29 NCRC head modeler Kirk Massey ranks gentlemanly knowledgeable E-fliers Ive met Kirk staff . dedicated meeting special needs Electric modeler stated catalog can tell first hand very well Call 409 856-4630 write Box 496 Willis TX 77378 catalog 98 LVRCS E-Meet held weekend June 13-14 near Easton PA always look forward attending affair CD Mike Stewart wife Patty did super job running meet face adverse weather threatened entire weekend Saturday morning brought major rainfall later lightened stopped stuck out got some great flying remainder two days meet always brings out plenty interesting things some pictured LVRCS flightline photo presents old new 11-year-old all-balsa profile Ampeater bipe simply could keep up Chris Trues modified Kyosho T-33 Chris replaced stock power system Astro turbo 05 Wemotek fan 10 1250 SCRs 44 ounces moves think entire crowd quite impressed its commanding though comfortable performance Chris likes em extra hot does note stock T-33 supplied power system also flies well may biased got impression much comment T-33 got also did Ampeaterbut entirely different reasons first showed airplane February 1988 column all-balsa craft built whim no plans flew great right start drew rather limited flightline interest time has languishing hangar mostly unused over years recently refitted new six-cell geared power system chose flighttest home-brew ESC design took LVRCSagain whim cting little flightline interest What difference decade makes Maybe its because profile has gained commercial acceptance intervening years crowd loved got several inquiries plans have construction article admit looks charming airat distance course Speed 400 airplanes quite popular think Tom Hunt ModelAir Tech wins having Speed 400 craft flightline should since designs sells plans em photo shows collection ModelAir-Tech Speed 400 craft including latest Wing Watt design Wing Watt 16-ounce 40-inch pusher configuration elevons mixing function required radio/installation low-cost designs based simple light structures consisting mostly /x x a strip ModelAir-Tech supplies November1998 97 ModelAir-Techs line up all-stick Speed 400 designs Wing Watt latest fun series Reverse-mounted direct-drive folder used six-volt Speed 400 Blue Foamie cheap-and-dirty easy Speed 400 got lots Wing Watt Modelair-Tech Elevons steer creation laughs flew well Great one-design club event plans well other well-known products like belt drives Contact Tom Box 1467 Lake Grove NY 11755-0898 Phone/fax 516 981-0372 E-mail THunt95l47@aolcom plans also available New Creations Blue Foamie $15 400-size kit Pat Mattes 9732 Lafayette Center Rd Yoder IN 46798-9723 got lot chuckles some real appreciation time Dereck Woodward flew Dereck graciously handed controls yes does fly whole lot better looks Ive just opted two-for-$29 e wing $9 inc postage deal 36-inch wing features true Clark Y section airplane can mostly assembled tape As name suggests craft made mostly blue foam has some wood spar aft surfaces As might expect burgeoning interest Speed 400 size airplanes theres corresponding increase appropriately-sized speed controls receivers servos etc also some special problems peculiar pursuit example because small sizes low weights involved BEC-equipped ESCs commonplace Speed 400 craft ESCs built surface-mount technology SMT quite tiny Being small using such components ESCs capable much heat dissipationas more modelers finding out its running motor thats problem BEC deviceusually low-overhead three-terminal regulator ICmust dissipate heat associated powering airborne radio servos represent largest load See March 98 column reference Depending system makeup associated heat can considerable regulator ICs have internal shutdown protection get too hot folks shuts down radio main culprits servosthe number kind FMA 580s 590s popular servos Speed 400 crowd what Im hearing same-size powerful S90 often too much load some tiny BEC-equipped ESCs seems 580s lower current drain preferred application decided look matter greater detail photo shows test setup makes use Servo Cycler September 1998 MA additional homemade test accessory called RC System Analyzer latter device measures average servo current peak servo current minimum system voltage servos moved Cycler does moving ie provides stepped swept drive signal servo under test Parameter readout DVM shown other black box seen photo convenience-packaged 48 volt Ni-Cd bench battery used receiver pack chose evaluate five relatively small servos hand results tabulated below average servo current read Cycler smoothly slowly slewing servo back forth over its range short-duration peak current captured Cycler set rapidly step servo back forth over range momentary peak occurs servo either starts moving changes direction photo taken S90 place DVM reading almost 13 amps peakthe highest bunch same time seen table S90 much different others regard average current drain tested flight lot servo starts stops reverses combined running average current frequent high current peaks add up considerable total average current corresponding high power dissipation BEC IC can shut down protect itself its greater problem servos have course SERVO mfgr/model Airtronics 94501 Hiteck H580 FMA S80 FMA S90 Futaba S133 AVG CURRENT milliAmps 93 80 150 130 160 PEAK milliAmps 850 960 860 1280 710 Lets try shrink BEC/ESC size down point useless Considering BEC function eliminates receiver battery surely some reasonable size weight tradeoff will still render net gain weight reduction adequate performance reliability reasonably small package think may time make some todays tiniest ESCs larger better handle dissipation either go back using receiver pack 98 Model Aviation s Trues Kyosho T-33 hotter power system authors Ampeater all-balsa bipe six cells geared car motor Authors Electronic Speed Control bench breadboard plus numerous prototype ESCs possible build-your-own ESC presentation Test setup measure average peak servo currents Some tiny BEC-equipped ESCs overheat shut down receiver Another photo illustrates ongoing efforts regard Readers have conveyed steady interest build-your own ESC article Ive pursuing design approach may fit need future Its unrealistic readers attempt surface mount technology As result photo shows several versions evolving ESC designbut built discrete leaded parts way ESCs built past might view efforts outdated view ESCs buildable modelers least thats goal Another aspect buildable feature parts Im using readily available modelers reasonable cost no difficult mechanical assembly aspects What see evolving middle range design covering six 16 cells having optional BEC optional delayed soft brake nonlinear transfer characteristic adequate heat-sinking weighing two ounces nominal wire connectors see size settling out somewhere around 13 x 21 inchesnot small todays standards large some earlier commercial designs Clearly intended Speed 400s giants As write Im up version eight Since Im interested circuit design details right now Ive bothered printed circuit board layouts Rather Ive used holeboard assemble signal processing circuitry some K&S aluminum sheet mount power FETS low overhead regulator working well enough may bother pc layout Noting once again hobby fun well Im having Its 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