George M Mye D 7adiomchnque ABSTRACT Battery charger basics CARING Nicad1 batteriesPart kinds advice about caring Ni cads 11 call Ni-Cds usual editorial style RMcM peo ple selling battery-care devices Some people re charge batteries put use Other people charge regular inter vals whether need Still others keep charged time trickle chargers Everybody succeeds Whos right nickel-cadmium Ni-Cd cell very toler ant abuse neglect makes hard define wrong answers Its service life mea sured terms available discharge/recharge cy cles exceeds needs Rightness deter mined conditions under batteries used example pick up por table telephone expect work immedi ately Portable telephones have rechargeable bat teries kept trickle charger Lets answer some reader questions 1 Q Whats difference between cell battery A cell single energy storage unit has two electrical terminals called positive tive - shows characteristic volt age charged characteristic voltage Ni-Cd cell 125 volts DC lead-acid cell 15 volts characteristic voltage makes easy differentiate various types cells resorting cutting open kinds cells some recharge able others A battery electrically connected group cells RC service typical see four cells used flight packs airplane eight cells inside transmitters although other numbers can beand sometimes areused battery fitted cable plug installed shrink wrap and/or container some kind call battery pack simply pack 2 Q What about C numbers A cell described amount en ergy will store called capacity indicated capital C common cells used RC service about size common AA pencell will store 550 milliamp-hours en ergy hence C mAb mAh iamps x hours will have noticed electrical energy stored cell has dimension current flow over time Amperes measure rate current flow milliamp 1/1000 ampere 550-mAh cell will deliver 550/1000 amp about /2 amp about hour Does mean will also deliver 550 amps 1/1000 hour Almost exactly internal connec tions would probably blow Out tried de liver much current Besides limit extent chemical reactions af 36 Model Aviation Ulu dii Fully di rate y ter providing electricity being ex tracted inside cell such short time course youre talking about explosion long time ago somebody decided nickelcadmium cells should discharged end test voltage I VDC volts direct cur rent current drain should chosen would no appreciable heating cell Given construction cells day discharge current set took two hours get end test voltage So C rating really saying can draw 275 mA two hours bring new freshly charged 550-mAb cell back down 11 VDC draw current cell rated 550 mAh rate faster 275 mA en ergy available work will less rated capacity because some energy will lost heating cells energy won available doing external work higher rate draw energy en ergy goes heat less available work usual Electric airplane setup discharges 1 200-mAh battery about eight minutes can calculate current drawn about 9 amps 12 x 60/8 9 can feel cells get warm Thats Electric airplanes have cooling vents o hou l1O long time recoverable energy turn motor 3 Q What about memory loss capacity Nickel-cadmium batteries develop memory normal RC service What will store little less charge time recharged Eventually time different various designs differ ent ways batteries used battery pack will able hold about half what could hold new Battery manufacturers con sider drop half rated capacity end useful life fly weekends recharge before after flying should take about 10 years reach level maybe longer 4 Q lost-capacity fix observe Ni-Cds have lost some capacity discharge 1 s per cell 44 VDC four-cell flight pack 88 VDC eight-cell transmitter pack can discharge easily simply attaching 10-ohm 10-watt resistor between inals Record time takes drop cell voltage 11 VDC Next recharge usually best re charge slow rate first time Discharge measure time again Recharge again can re charge rates up value C means battery constructed C mAh 70 Froehlkh Farm Rd Hicksville NY 11801 PROCEOL salable vents reclit tir nittoff bat inside cag same kind argument applies recharg ing will discuss later Energy goes heating cells during recharge QU Y ana r VOL chargd cells can recharged rate 550 mA Re peat procedure five times task can simplified use Ace R/C Digipace CaRa Automatic Cycler-Charger similar de vices record battery capacity time run discharges may see pack held 50% rated capacity before fix holds 75% 95% afterward recovery normal will last Note pack usually will recover 100% capac ity New packs will always hold used packs Thats can buy used packs people race electric autosvery cheaply packs wont win races will still fly plane very nicely years started 50% rated capacity did see recovery cells should discarded 5 Q about neglect factor Cells left idle long time like over winter will accept full charge first time recharged Cycle above will recover As example recently reactivated some carpet racers children used play cars have packs six 1200-mAb cells power packs have idle least 10 years surprised find volt meter showed some voltage pack tested six packs typical test showed 10 min utes after first charge 30 minutes after sec ond 60 after third 80 after fourth 90 after fifth little exercise arithmetic shows 90 minutes discharge average 8 volts 10-ohm resistor equals about 1200 mAh six idle packs recovered rated capacity five cycles new used hold up 10% rated capacity tests recharging done rate 900 mAh about 90 minutes using fast charger VDD voltage-drop detection also known peak detection 6 Q about overcharging factor A According friend Larry Sribnick president SR Batteries Ni-Cd battery packs RC service will die repeated over charging see evidence moment take pack apart seal end over charged cell will have white green brown powder grooves powder shows plastic seal under end cap has punc tured Most often puncture due excessive gas pressure case brought about over chargingparticularly high rates Once seal has punctured tiny bit dampness inside released causes kinds bad things corrosion wire pack plug inside wire nsulation cant see Clear evi lence corrosion will found ry solder old wire onto new cell find hat cant make solder stick really bad ases pins battery pack plug will cor rode usually green right through gold plat ing Replace battery cable whenever re place battery 7 Q Which right charger use Simple Use charger came system Overcharging likely hap pen use fast chargers kind recharge cell less hour Continued page 144 ELIMI4TE COMPETITIO April 1990 37 flV71/\F S PROUD r2LTLAJL-AU\ATO ANNOUNCE THE WORLDS SMALLEST ON-BOARD GLO-SWITCH WIRE DIRECT OR Y INTO ANY RECEIVER OUTPUT INCLUDES REVERSING SWITCH ADJUSTABLE 0N POINT AND LED INDICATOR HANDLES 0 TO 12 VOLTS AT UP TO 10 AMPS lf4cc aedad46te ae - 464 a4/ CALL OR WRITE FOR MORE INFO JOMAR PRODUCTS 513-474-0985 2028 Knightsbridge Dr Cinti OH 45244 ACTUAL SIZEI PERFECT PATTERNS Fly perfect patterns time F&Es very affordable fiberglass-and-foam pattern planes Vertigo II oldie goodie 65 span 50 fuselage 600 l wing area Designed 60 power Trike gear Kit lA-i 038 $10995 plus shipping NPhoenix V VI proven trophy-winners board renowned Don Lowe Choose 3 sizes power requirements suit own competitive needs Phoenix V 40 Kit #A-1026 $8995 Phoenix V 60 Kit #A-1027 $9995 Phoenix VI 80 Kit #A-1028 $10995 plus shipping Cure-Air aerobat anhedral 64 span 680 l wing area Special anhedral stabs make Cure-Air behave like dream t side up upside down 60 power Kit lA-i 006 $10995 plus shipping F8E kits feature precision-molded fiberglass fuselages balsa-covered foam wings reduced weight Write call FREE catalog pattern planes stand-off scale current classic warbirds trainer lodayl 1836 Stout Drive inster PA 18974 675-9882 Dler inquii invited SHORT KiTS INCLUOt STYROFOAM WING CORES CANOPIES COLNES PLANS ENGINE MOUNTS PIREWALLS MOLDED MISC PARTS SOME HARDWARE AND MATERIALS LIST FOR BALSA AND ADDITIONAL OFF THE SHELF ITEMS AMMO ZERO SR SPAN 3750 PAD TOMAHAWE 55SPAN3750P3R AIRACORRA 55SPAN3750 P510 MUSTANG 54SPAN37 50 S COOL FOLGORE SRSPAN3750YR FOCEE WOLF 1W 34 SPAN 3730 A26 INVADER 65 SPAN . SAPSr~ P3e LIGHTNING 70 SPAN . 74 95 FAA COeSAIR 56 SPAN . 44 PS11IE~ ORDRRIPdG SEND CHECK OR MONEY CR009 FOR REQUIRED ARROUNT PLES $450 PER KIT CANADIANS ADD 3750 ILEINOIS RESIDENTS ADD RVS% YAK WING Mfg 306 E Simmons Galesburg IL 61401 DUAL STRUT NICKEL PLATED NOSE GEAR H 9 Fults Tooling PO Box 95 Champaign IL 618241 Safety/Preston Continued page 141 18 stated boy play ing model airplane garage home lit disposable lighter melt fuel tube model lighter ignited fumes nearby fuel can caused explosion newspaper articles did identify model Pauls accompanying let ter said believed model question RTF ready-to-fly-7--Ed Control Line plane appears good example introduce son hobby Have safe month Radio Technique/Myers Continued page 37 overntght charger can overcharge keep putting back take out Chargers rated current de liver tong takes recharge battery So know what he/she ing Simple answer Use ammeter cut wires charger connect cut ends ammeter nor cut other wtre charger puts out 45 55 mA what get chargers come RC set would rated C/tO charging AA-sized pencell pack Typi cally such batteries will constructed cells rated between 450 550 mAh So C di vided charging current equals 450/45 50/55 sed way referred C/tO charger overnight charger will see shortly Now very same charger used charge lOO-mAH micro-pack would called what Class Thats right would C/2 charger 100/50 w plug same charger 4000-mAb D-cell what have Obviously its 4000/50 ould called C/80 charger care long time ago somebody discovered C/tO charger could left connected dis charged cell overnight cell would fully charged morning based turn printer airfoil plotter with.. FOILED AGAIN! C PLOT AIRFOILS IN ANY CHORD UP TO 24 INCHES MODIFY ThICKNESS CAMBER & TRAILING EDGE PLOT SKIN THICKNESS FOR SHEErED WINGS ENTER DATA EASILY VIA INTELLIGENT EDITOR USER-FRIENDLY MENU-DRIVEN OPERATION INCLUDES 18-PAGE ILLUSTRATED USER MANUAL $3995 RRURPCI7/TM,ER LNmpw.wMdaep. AdAW5S2533Au CYGNET Software 24843 Del Prado #141b Dana Point CA 92629 eight-hour workday really closer nine hours long take account lunch washup couple coffee breaks So overnight charger born Overnight means something order 15 hours charging C/tO Thats overcharge modern Ni-Cds toler ate little overcharge helps ensure cells come same final voltage called leveling pack should bear mind basic assumption pack fully discharged start 15-hour re charge should also remember Ni-Cd batteries last long timebut forever tI observed charging C/to could go over weekend damaging cells somebody got busy another job found cell left connected C/tO charger long time months would show signs overcharging left connected C/SO charger would retain its charge suffering bad effects overcharging trickle charger born Battery packs must fully charged before attached trickle charger because proper trickle-charging rate fast enough make up tosses caused internal chemistry called self-discharge trickle charger puts out enough current recharge discharged pack batteries could damaged over long time overcharging Going other direction somebody got im patient After ruining few good cells found charging C/3 rate recharged cells three four hours producing signs overcharging quick charger born Some really impatient people wanted get job done no time So dump chargers invented Cells began blow up havent lived until youve seen seated D-size NiCd cell like telephone company uses ex plode like hand grenade Cells made consumer market have vents prevent such explosions connecting single Ni-Cd cell directly 12-volt battery order shock charge can have se rious consequences medical insurance Like Russian roulette get away until dont Cooler heads prevailed some complicated solutions found Internal changes geome try chemistry created fast-charge cells have spring-loaded resealable vents can recharged 15 minutes 4C price Fast-charge cells will dis charge themselves very quickly fastcharge cells will ruined severely overcharge time vent opens cell looses some electrolyte thereby losing capac ity 144 Model Aviation Farnsworth & ElroyInc WHATIWILL YOU DO FOR 1991 Trushjur turrent system hanes can still use present radio systems RCDsPLATINUM GRADE AM FM FCC/AMA listed 1991 ivers fit right R/C systems Fly safely bullet-proof receivers NOW D RCD 100* LI RCD 150* LII RCD200* LI RCD300* Futaba GAM Futaba JAM Futaba J FM Alrtronks AM *Must specify channel# order ORDER BY PHONE CA 800 822-1688 LI RCD 400* Airironics FM US 800 228 -3237 ONLY $59 96 0 2131 Old Oakland Rd Son Jose 95131 1578 should mention point rechargeable cells electrochemical devices reversible chemistry within cell permits accurnula tion release electrical energy chemis try depends r solution potassium hy droxide electrolyte re sides blotter separates plates electrochemistry occurs charging pro cess releases gaseous oxygen So long charging done slow rate C/3 less gas can reabsorbed within system Overcharging characterized release oxygen rate too high reabsorption hence increase pressure point cell vented oxygen permanently lost system loss oxygen reduces cell capacity avoid overcharging fast chargers spec ify used discharged cells include atimer cuts off less 100% full recharge discharged cell people insist having possible coulomb cells will add VDD voltage drop detector Most cells will show drop ter minal voltage enter overcharge So VDD circuits added extra expense pro tect overcharging Next month will discuss some real-life charg ers fast quick trickle persuasions Dream Field/Larsen Continued page 39 Beresford Republic sent reporter/photog rapher fun fly two press releases photos have sibce printed willing enthusiastic support Mayor Muller city council city employees has extremely encourag ing time flying fields becom ing harder obtain keep its refresh ing see what rural community can itself goal providing recrea tion its citizens city Beresford has developed free site area RC fliers clubs would willing pay dearly Wed have satisfied simply place fly So deluxe field appearedand few short weekswe elated Beresford Area Radi6 Flyers AMA Chapter 2577 chartered March 31 1989 club provides supervision field well AMA-sponsored liability surance liability question reservation city fathers expressed about entire project AMA inApril 1990 145 OR Get RCDs New 1991-Ready receiver THE PIPER BRAVE scale model Pipers latest Ag plane t wing spafi 30-33 lbs 5 cc power lb payload ational flaps hopper door onal Spreader Kit formed aluminum landing gear rglass cowls um-formed canopy tucted extruded foam ply hardwood e BRAVE95 OPTIONAL $ 1fl95 NOt moer l actuallyKIT$269SPREADER SEND $100 FOR CATALOG OFQ /4/RT 1 NEODESHA KS 66757 SAC KITS AND ACCESSORIESN~316 325-2821 Free Shipping Kit OrdersScott Airplane CompanyVISA /MASTERCARD
Edition: Model Aviation - 1990/04
Page Numbers: 36, 37, 144, 145
George M Mye D 7adiomchnque ABSTRACT Battery charger basics CARING Nicad1 batteriesPart kinds advice about caring Ni cads 11 call Ni-Cds usual editorial style RMcM peo ple selling battery-care devices Some people re charge batteries put use Other people charge regular inter vals whether need Still others keep charged time trickle chargers Everybody succeeds Whos right nickel-cadmium Ni-Cd cell very toler ant abuse neglect makes hard define wrong answers Its service life mea sured terms available discharge/recharge cy cles exceeds needs Rightness deter mined conditions under batteries used example pick up por table telephone expect work immedi ately Portable telephones have rechargeable bat teries kept trickle charger Lets answer some reader questions 1 Q Whats difference between cell battery A cell single energy storage unit has two electrical terminals called positive tive - shows characteristic volt age charged characteristic voltage Ni-Cd cell 125 volts DC lead-acid cell 15 volts characteristic voltage makes easy differentiate various types cells resorting cutting open kinds cells some recharge able others A battery electrically connected group cells RC service typical see four cells used flight packs airplane eight cells inside transmitters although other numbers can beand sometimes areused battery fitted cable plug installed shrink wrap and/or container some kind call battery pack simply pack 2 Q What about C numbers A cell described amount en ergy will store called capacity indicated capital C common cells used RC service about size common AA pencell will store 550 milliamp-hours en ergy hence C mAb mAh iamps x hours will have noticed electrical energy stored cell has dimension current flow over time Amperes measure rate current flow milliamp 1/1000 ampere 550-mAh cell will deliver 550/1000 amp about /2 amp about hour Does mean will also deliver 550 amps 1/1000 hour Almost exactly internal connec tions would probably blow Out tried de liver much current Besides limit extent chemical reactions af 36 Model Aviation Ulu dii Fully di rate y ter providing electricity being ex tracted inside cell such short time course youre talking about explosion long time ago somebody decided nickelcadmium cells should discharged end test voltage I VDC volts direct cur rent current drain should chosen would no appreciable heating cell Given construction cells day discharge current set took two hours get end test voltage So C rating really saying can draw 275 mA two hours bring new freshly charged 550-mAb cell back down 11 VDC draw current cell rated 550 mAh rate faster 275 mA en ergy available work will less rated capacity because some energy will lost heating cells energy won available doing external work higher rate draw energy en ergy goes heat less available work usual Electric airplane setup discharges 1 200-mAh battery about eight minutes can calculate current drawn about 9 amps 12 x 60/8 9 can feel cells get warm Thats Electric airplanes have cooling vents o hou l1O long time recoverable energy turn motor 3 Q What about memory loss capacity Nickel-cadmium batteries develop memory normal RC service What will store little less charge time recharged Eventually time different various designs differ ent ways batteries used battery pack will able hold about half what could hold new Battery manufacturers con sider drop half rated capacity end useful life fly weekends recharge before after flying should take about 10 years reach level maybe longer 4 Q lost-capacity fix observe Ni-Cds have lost some capacity discharge 1 s per cell 44 VDC four-cell flight pack 88 VDC eight-cell transmitter pack can discharge easily simply attaching 10-ohm 10-watt resistor between inals Record time takes drop cell voltage 11 VDC Next recharge usually best re charge slow rate first time Discharge measure time again Recharge again can re charge rates up value C means battery constructed C mAh 70 Froehlkh Farm Rd Hicksville NY 11801 PROCEOL salable vents reclit tir nittoff bat inside cag same kind argument applies recharg ing will discuss later Energy goes heating cells during recharge QU Y ana r VOL chargd cells can recharged rate 550 mA Re peat procedure five times task can simplified use Ace R/C Digipace CaRa Automatic Cycler-Charger similar de vices record battery capacity time run discharges may see pack held 50% rated capacity before fix holds 75% 95% afterward recovery normal will last Note pack usually will recover 100% capac ity New packs will always hold used packs Thats can buy used packs people race electric autosvery cheaply packs wont win races will still fly plane very nicely years started 50% rated capacity did see recovery cells should discarded 5 Q about neglect factor Cells left idle long time like over winter will accept full charge first time recharged Cycle above will recover As example recently reactivated some carpet racers children used play cars have packs six 1200-mAb cells power packs have idle least 10 years surprised find volt meter showed some voltage pack tested six packs typical test showed 10 min utes after first charge 30 minutes after sec ond 60 after third 80 after fourth 90 after fifth little exercise arithmetic shows 90 minutes discharge average 8 volts 10-ohm resistor equals about 1200 mAh six idle packs recovered rated capacity five cycles new used hold up 10% rated capacity tests recharging done rate 900 mAh about 90 minutes using fast charger VDD voltage-drop detection also known peak detection 6 Q about overcharging factor A According friend Larry Sribnick president SR Batteries Ni-Cd battery packs RC service will die repeated over charging see evidence moment take pack apart seal end over charged cell will have white green brown powder grooves powder shows plastic seal under end cap has punc tured Most often puncture due excessive gas pressure case brought about over chargingparticularly high rates Once seal has punctured tiny bit dampness inside released causes kinds bad things corrosion wire pack plug inside wire nsulation cant see Clear evi lence corrosion will found ry solder old wire onto new cell find hat cant make solder stick really bad ases pins battery pack plug will cor rode usually green right through gold plat ing Replace battery cable whenever re place battery 7 Q Which right charger use Simple Use charger came system Overcharging likely hap pen use fast chargers kind recharge cell less hour Continued page 144 ELIMI4TE COMPETITIO April 1990 37 flV71/\F S PROUD r2LTLAJL-AU\ATO ANNOUNCE THE WORLDS SMALLEST ON-BOARD GLO-SWITCH WIRE DIRECT OR Y INTO ANY RECEIVER OUTPUT INCLUDES REVERSING SWITCH ADJUSTABLE 0N POINT AND LED INDICATOR HANDLES 0 TO 12 VOLTS AT UP TO 10 AMPS lf4cc aedad46te ae - 464 a4/ CALL OR WRITE FOR MORE INFO JOMAR PRODUCTS 513-474-0985 2028 Knightsbridge Dr Cinti OH 45244 ACTUAL SIZEI PERFECT PATTERNS Fly perfect patterns time F&Es very affordable fiberglass-and-foam pattern planes Vertigo II oldie goodie 65 span 50 fuselage 600 l wing area Designed 60 power Trike gear Kit lA-i 038 $10995 plus shipping NPhoenix V VI proven trophy-winners board renowned Don Lowe Choose 3 sizes power requirements suit own competitive needs Phoenix V 40 Kit #A-1026 $8995 Phoenix V 60 Kit #A-1027 $9995 Phoenix VI 80 Kit #A-1028 $10995 plus shipping Cure-Air aerobat anhedral 64 span 680 l wing area Special anhedral stabs make Cure-Air behave like dream t side up upside down 60 power Kit lA-i 006 $10995 plus shipping F8E kits feature precision-molded fiberglass fuselages balsa-covered foam wings reduced weight Write call FREE catalog pattern planes stand-off scale current classic warbirds trainer lodayl 1836 Stout Drive inster PA 18974 675-9882 Dler inquii invited SHORT KiTS INCLUOt STYROFOAM WING CORES CANOPIES COLNES PLANS ENGINE MOUNTS PIREWALLS MOLDED MISC PARTS SOME HARDWARE AND MATERIALS LIST FOR BALSA AND ADDITIONAL OFF THE SHELF ITEMS AMMO ZERO SR SPAN 3750 PAD TOMAHAWE 55SPAN3750P3R AIRACORRA 55SPAN3750 P510 MUSTANG 54SPAN37 50 S COOL FOLGORE SRSPAN3750YR FOCEE WOLF 1W 34 SPAN 3730 A26 INVADER 65 SPAN . SAPSr~ P3e LIGHTNING 70 SPAN . 74 95 FAA COeSAIR 56 SPAN . 44 PS11IE~ ORDRRIPdG SEND CHECK OR MONEY CR009 FOR REQUIRED ARROUNT PLES $450 PER KIT CANADIANS ADD 3750 ILEINOIS RESIDENTS ADD RVS% YAK WING Mfg 306 E Simmons Galesburg IL 61401 DUAL STRUT NICKEL PLATED NOSE GEAR H 9 Fults Tooling PO Box 95 Champaign IL 618241 Safety/Preston Continued page 141 18 stated boy play ing model airplane garage home lit disposable lighter melt fuel tube model lighter ignited fumes nearby fuel can caused explosion newspaper articles did identify model Pauls accompanying let ter said believed model question RTF ready-to-fly-7--Ed Control Line plane appears good example introduce son hobby Have safe month Radio Technique/Myers Continued page 37 overntght charger can overcharge keep putting back take out Chargers rated current de liver tong takes recharge battery So know what he/she ing Simple answer Use ammeter cut wires charger connect cut ends ammeter nor cut other wtre charger puts out 45 55 mA what get chargers come RC set would rated C/tO charging AA-sized pencell pack Typi cally such batteries will constructed cells rated between 450 550 mAh So C di vided charging current equals 450/45 50/55 sed way referred C/tO charger overnight charger will see shortly Now very same charger used charge lOO-mAH micro-pack would called what Class Thats right would C/2 charger 100/50 w plug same charger 4000-mAb D-cell what have Obviously its 4000/50 ould called C/80 charger care long time ago somebody discovered C/tO charger could left connected dis charged cell overnight cell would fully charged morning based turn printer airfoil plotter with.. FOILED AGAIN! C PLOT AIRFOILS IN ANY CHORD UP TO 24 INCHES MODIFY ThICKNESS CAMBER & TRAILING EDGE PLOT SKIN THICKNESS FOR SHEErED WINGS ENTER DATA EASILY VIA INTELLIGENT EDITOR USER-FRIENDLY MENU-DRIVEN OPERATION INCLUDES 18-PAGE ILLUSTRATED USER MANUAL $3995 RRURPCI7/TM,ER LNmpw.wMdaep. AdAW5S2533Au CYGNET Software 24843 Del Prado #141b Dana Point CA 92629 eight-hour workday really closer nine hours long take account lunch washup couple coffee breaks So overnight charger born Overnight means something order 15 hours charging C/tO Thats overcharge modern Ni-Cds toler ate little overcharge helps ensure cells come same final voltage called leveling pack should bear mind basic assumption pack fully discharged start 15-hour re charge should also remember Ni-Cd batteries last long timebut forever tI observed charging C/to could go over weekend damaging cells somebody got busy another job found cell left connected C/tO charger long time months would show signs overcharging left connected C/SO charger would retain its charge suffering bad effects overcharging trickle charger born Battery packs must fully charged before attached trickle charger because proper trickle-charging rate fast enough make up tosses caused internal chemistry called self-discharge trickle charger puts out enough current recharge discharged pack batteries could damaged over long time overcharging Going other direction somebody got im patient After ruining few good cells found charging C/3 rate recharged cells three four hours producing signs overcharging quick charger born Some really impatient people wanted get job done no time So dump chargers invented Cells began blow up havent lived until youve seen seated D-size NiCd cell like telephone company uses ex plode like hand grenade Cells made consumer market have vents prevent such explosions connecting single Ni-Cd cell directly 12-volt battery order shock charge can have se rious consequences medical insurance Like Russian roulette get away until dont Cooler heads prevailed some complicated solutions found Internal changes geome try chemistry created fast-charge cells have spring-loaded resealable vents can recharged 15 minutes 4C price Fast-charge cells will dis charge themselves very quickly fastcharge cells will ruined severely overcharge time vent opens cell looses some electrolyte thereby losing capac ity 144 Model Aviation Farnsworth & ElroyInc WHATIWILL YOU DO FOR 1991 Trushjur turrent system hanes can still use present radio systems RCDsPLATINUM GRADE AM FM FCC/AMA listed 1991 ivers fit right R/C systems Fly safely bullet-proof receivers NOW D RCD 100* LI RCD 150* LII RCD200* LI RCD300* Futaba GAM Futaba JAM Futaba J FM Alrtronks AM *Must specify channel# order ORDER BY PHONE CA 800 822-1688 LI RCD 400* Airironics FM US 800 228 -3237 ONLY $59 96 0 2131 Old Oakland Rd Son Jose 95131 1578 should mention point rechargeable cells electrochemical devices reversible chemistry within cell permits accurnula tion release electrical energy chemis try depends r solution potassium hy droxide electrolyte re sides blotter separates plates electrochemistry occurs charging pro cess releases gaseous oxygen So long charging done slow rate C/3 less gas can reabsorbed within system Overcharging characterized release oxygen rate too high reabsorption hence increase pressure point cell vented oxygen permanently lost system loss oxygen reduces cell capacity avoid overcharging fast chargers spec ify used discharged cells include atimer cuts off less 100% full recharge discharged cell people insist having possible coulomb cells will add VDD voltage drop detector Most cells will show drop ter minal voltage enter overcharge So VDD circuits added extra expense pro tect overcharging Next month will discuss some real-life charg ers fast quick trickle persuasions Dream Field/Larsen Continued page 39 Beresford Republic sent reporter/photog rapher fun fly two press releases photos have sibce printed willing enthusiastic support Mayor Muller city council city employees has extremely encourag ing time flying fields becom ing harder obtain keep its refresh ing see what rural community can itself goal providing recrea tion its citizens city Beresford has developed free site area RC fliers clubs would willing pay dearly Wed have satisfied simply place fly So deluxe field appearedand few short weekswe elated Beresford Area Radi6 Flyers AMA Chapter 2577 chartered March 31 1989 club provides supervision field well AMA-sponsored liability surance liability question reservation city fathers expressed about entire project AMA inApril 1990 145 OR Get RCDs New 1991-Ready receiver THE PIPER BRAVE scale model Pipers latest Ag plane t wing spafi 30-33 lbs 5 cc power lb payload ational flaps hopper door onal Spreader Kit formed aluminum landing gear rglass cowls um-formed canopy tucted extruded foam ply hardwood e BRAVE95 OPTIONAL $ 1fl95 NOt moer l actuallyKIT$269SPREADER SEND $100 FOR CATALOG OFQ /4/RT 1 NEODESHA KS 66757 SAC KITS AND ACCESSORIESN~316 325-2821 Free Shipping Kit OrdersScott Airplane CompanyVISA /MASTERCARD
Edition: Model Aviation - 1990/04
Page Numbers: 36, 37, 144, 145
George M Mye D 7adiomchnque ABSTRACT Battery charger basics CARING Nicad1 batteriesPart kinds advice about caring Ni cads 11 call Ni-Cds usual editorial style RMcM peo ple selling battery-care devices Some people re charge batteries put use Other people charge regular inter vals whether need Still others keep charged time trickle chargers Everybody succeeds Whos right nickel-cadmium Ni-Cd cell very toler ant abuse neglect makes hard define wrong answers Its service life mea sured terms available discharge/recharge cy cles exceeds needs Rightness deter mined conditions under batteries used example pick up por table telephone expect work immedi ately Portable telephones have rechargeable bat teries kept trickle charger Lets answer some reader questions 1 Q Whats difference between cell battery A cell single energy storage unit has two electrical terminals called positive tive - shows characteristic volt age charged characteristic voltage Ni-Cd cell 125 volts DC lead-acid cell 15 volts characteristic voltage makes easy differentiate various types cells resorting cutting open kinds cells some recharge able others A battery electrically connected group cells RC service typical see four cells used flight packs airplane eight cells inside transmitters although other numbers can beand sometimes areused battery fitted cable plug installed shrink wrap and/or container some kind call battery pack simply pack 2 Q What about C numbers A cell described amount en ergy will store called capacity indicated capital C common cells used RC service about size common AA pencell will store 550 milliamp-hours en ergy hence C mAb mAh iamps x hours will have noticed electrical energy stored cell has dimension current flow over time Amperes measure rate current flow milliamp 1/1000 ampere 550-mAh cell will deliver 550/1000 amp about /2 amp about hour Does mean will also deliver 550 amps 1/1000 hour Almost exactly internal connec tions would probably blow Out tried de liver much current Besides limit extent chemical reactions af 36 Model Aviation Ulu dii Fully di rate y ter providing electricity being ex tracted inside cell such short time course youre talking about explosion long time ago somebody decided nickelcadmium cells should discharged end test voltage I VDC volts direct cur rent current drain should chosen would no appreciable heating cell Given construction cells day discharge current set took two hours get end test voltage So C rating really saying can draw 275 mA two hours bring new freshly charged 550-mAb cell back down 11 VDC draw current cell rated 550 mAh rate faster 275 mA en ergy available work will less rated capacity because some energy will lost heating cells energy won available doing external work higher rate draw energy en ergy goes heat less available work usual Electric airplane setup discharges 1 200-mAh battery about eight minutes can calculate current drawn about 9 amps 12 x 60/8 9 can feel cells get warm Thats Electric airplanes have cooling vents o hou l1O long time recoverable energy turn motor 3 Q What about memory loss capacity Nickel-cadmium batteries develop memory normal RC service What will store little less charge time recharged Eventually time different various designs differ ent ways batteries used battery pack will able hold about half what could hold new Battery manufacturers con sider drop half rated capacity end useful life fly weekends recharge before after flying should take about 10 years reach level maybe longer 4 Q lost-capacity fix observe Ni-Cds have lost some capacity discharge 1 s per cell 44 VDC four-cell flight pack 88 VDC eight-cell transmitter pack can discharge easily simply attaching 10-ohm 10-watt resistor between inals Record time takes drop cell voltage 11 VDC Next recharge usually best re charge slow rate first time Discharge measure time again Recharge again can re charge rates up value C means battery constructed C mAh 70 Froehlkh Farm Rd Hicksville NY 11801 PROCEOL salable vents reclit tir nittoff bat inside cag same kind argument applies recharg ing will discuss later Energy goes heating cells during recharge QU Y ana r VOL chargd cells can recharged rate 550 mA Re peat procedure five times task can simplified use Ace R/C Digipace CaRa Automatic Cycler-Charger similar de vices record battery capacity time run discharges may see pack held 50% rated capacity before fix holds 75% 95% afterward recovery normal will last Note pack usually will recover 100% capac ity New packs will always hold used packs Thats can buy used packs people race electric autosvery cheaply packs wont win races will still fly plane very nicely years started 50% rated capacity did see recovery cells should discarded 5 Q about neglect factor Cells left idle long time like over winter will accept full charge first time recharged Cycle above will recover As example recently reactivated some carpet racers children used play cars have packs six 1200-mAb cells power packs have idle least 10 years surprised find volt meter showed some voltage pack tested six packs typical test showed 10 min utes after first charge 30 minutes after sec ond 60 after third 80 after fourth 90 after fifth little exercise arithmetic shows 90 minutes discharge average 8 volts 10-ohm resistor equals about 1200 mAh six idle packs recovered rated capacity five cycles new used hold up 10% rated capacity tests recharging done rate 900 mAh about 90 minutes using fast charger VDD voltage-drop detection also known peak detection 6 Q about overcharging factor A According friend Larry Sribnick president SR Batteries Ni-Cd battery packs RC service will die repeated over charging see evidence moment take pack apart seal end over charged cell will have white green brown powder grooves powder shows plastic seal under end cap has punc tured Most often puncture due excessive gas pressure case brought about over chargingparticularly high rates Once seal has punctured tiny bit dampness inside released causes kinds bad things corrosion wire pack plug inside wire nsulation cant see Clear evi lence corrosion will found ry solder old wire onto new cell find hat cant make solder stick really bad ases pins battery pack plug will cor rode usually green right through gold plat ing Replace battery cable whenever re place battery 7 Q Which right charger use Simple Use charger came system Overcharging likely hap pen use fast chargers kind recharge cell less hour Continued page 144 ELIMI4TE COMPETITIO April 1990 37 flV71/\F S PROUD r2LTLAJL-AU\ATO ANNOUNCE THE WORLDS SMALLEST ON-BOARD GLO-SWITCH WIRE DIRECT OR Y INTO ANY RECEIVER OUTPUT INCLUDES REVERSING SWITCH ADJUSTABLE 0N POINT AND LED INDICATOR HANDLES 0 TO 12 VOLTS AT UP TO 10 AMPS lf4cc aedad46te ae - 464 a4/ CALL OR WRITE FOR MORE INFO JOMAR PRODUCTS 513-474-0985 2028 Knightsbridge Dr Cinti OH 45244 ACTUAL SIZEI PERFECT PATTERNS Fly perfect patterns time F&Es very affordable fiberglass-and-foam pattern planes Vertigo II oldie goodie 65 span 50 fuselage 600 l wing area Designed 60 power Trike gear Kit lA-i 038 $10995 plus shipping NPhoenix V VI proven trophy-winners board renowned Don Lowe Choose 3 sizes power requirements suit own competitive needs Phoenix V 40 Kit #A-1026 $8995 Phoenix V 60 Kit #A-1027 $9995 Phoenix VI 80 Kit #A-1028 $10995 plus shipping Cure-Air aerobat anhedral 64 span 680 l wing area Special anhedral stabs make Cure-Air behave like dream t side up upside down 60 power Kit lA-i 006 $10995 plus shipping F8E kits feature precision-molded fiberglass fuselages balsa-covered foam wings reduced weight Write call FREE catalog pattern planes stand-off scale current classic warbirds trainer lodayl 1836 Stout Drive inster PA 18974 675-9882 Dler inquii invited SHORT KiTS INCLUOt STYROFOAM WING CORES CANOPIES COLNES PLANS ENGINE MOUNTS PIREWALLS MOLDED MISC PARTS SOME HARDWARE AND MATERIALS LIST FOR BALSA AND ADDITIONAL OFF THE SHELF ITEMS AMMO ZERO SR SPAN 3750 PAD TOMAHAWE 55SPAN3750P3R AIRACORRA 55SPAN3750 P510 MUSTANG 54SPAN37 50 S COOL FOLGORE SRSPAN3750YR FOCEE WOLF 1W 34 SPAN 3730 A26 INVADER 65 SPAN . SAPSr~ P3e LIGHTNING 70 SPAN . 74 95 FAA COeSAIR 56 SPAN . 44 PS11IE~ ORDRRIPdG SEND CHECK OR MONEY CR009 FOR REQUIRED ARROUNT PLES $450 PER KIT CANADIANS ADD 3750 ILEINOIS RESIDENTS ADD RVS% YAK WING Mfg 306 E Simmons Galesburg IL 61401 DUAL STRUT NICKEL PLATED NOSE GEAR H 9 Fults Tooling PO Box 95 Champaign IL 618241 Safety/Preston Continued page 141 18 stated boy play ing model airplane garage home lit disposable lighter melt fuel tube model lighter ignited fumes nearby fuel can caused explosion newspaper articles did identify model Pauls accompanying let ter said believed model question RTF ready-to-fly-7--Ed Control Line plane appears good example introduce son hobby Have safe month Radio Technique/Myers Continued page 37 overntght charger can overcharge keep putting back take out Chargers rated current de liver tong takes recharge battery So know what he/she ing Simple answer Use ammeter cut wires charger connect cut ends ammeter nor cut other wtre charger puts out 45 55 mA what get chargers come RC set would rated C/tO charging AA-sized pencell pack Typi cally such batteries will constructed cells rated between 450 550 mAh So C di vided charging current equals 450/45 50/55 sed way referred C/tO charger overnight charger will see shortly Now very same charger used charge lOO-mAH micro-pack would called what Class Thats right would C/2 charger 100/50 w plug same charger 4000-mAb D-cell what have Obviously its 4000/50 ould called C/80 charger care long time ago somebody discovered C/tO charger could left connected dis charged cell overnight cell would fully charged morning based turn printer airfoil plotter with.. FOILED AGAIN! C PLOT AIRFOILS IN ANY CHORD UP TO 24 INCHES MODIFY ThICKNESS CAMBER & TRAILING EDGE PLOT SKIN THICKNESS FOR SHEErED WINGS ENTER DATA EASILY VIA INTELLIGENT EDITOR USER-FRIENDLY MENU-DRIVEN OPERATION INCLUDES 18-PAGE ILLUSTRATED USER MANUAL $3995 RRURPCI7/TM,ER LNmpw.wMdaep. AdAW5S2533Au CYGNET Software 24843 Del Prado #141b Dana Point CA 92629 eight-hour workday really closer nine hours long take account lunch washup couple coffee breaks So overnight charger born Overnight means something order 15 hours charging C/tO Thats overcharge modern Ni-Cds toler ate little overcharge helps ensure cells come same final voltage called leveling pack should bear mind basic assumption pack fully discharged start 15-hour re charge should also remember Ni-Cd batteries last long timebut forever tI observed charging C/to could go over weekend damaging cells somebody got busy another job found cell left connected C/tO charger long time months would show signs overcharging left connected C/SO charger would retain its charge suffering bad effects overcharging trickle charger born Battery packs must fully charged before attached trickle charger because proper trickle-charging rate fast enough make up tosses caused internal chemistry called self-discharge trickle charger puts out enough current recharge discharged pack batteries could damaged over long time overcharging Going other direction somebody got im patient After ruining few good cells found charging C/3 rate recharged cells three four hours producing signs overcharging quick charger born Some really impatient people wanted get job done no time So dump chargers invented Cells began blow up havent lived until youve seen seated D-size NiCd cell like telephone company uses ex plode like hand grenade Cells made consumer market have vents prevent such explosions connecting single Ni-Cd cell directly 12-volt battery order shock charge can have se rious consequences medical insurance Like Russian roulette get away until dont Cooler heads prevailed some complicated solutions found Internal changes geome try chemistry created fast-charge cells have spring-loaded resealable vents can recharged 15 minutes 4C price Fast-charge cells will dis charge themselves very quickly fastcharge cells will ruined severely overcharge time vent opens cell looses some electrolyte thereby losing capac ity 144 Model Aviation Farnsworth & ElroyInc WHATIWILL YOU DO FOR 1991 Trushjur turrent system hanes can still use present radio systems RCDsPLATINUM GRADE AM FM FCC/AMA listed 1991 ivers fit right R/C systems Fly safely bullet-proof receivers NOW D RCD 100* LI RCD 150* LII RCD200* LI RCD300* Futaba GAM Futaba JAM Futaba J FM Alrtronks AM *Must specify channel# order ORDER BY PHONE CA 800 822-1688 LI RCD 400* Airironics FM US 800 228 -3237 ONLY $59 96 0 2131 Old Oakland Rd Son Jose 95131 1578 should mention point rechargeable cells electrochemical devices reversible chemistry within cell permits accurnula tion release electrical energy chemis try depends r solution potassium hy droxide electrolyte re sides blotter separates plates electrochemistry occurs charging pro cess releases gaseous oxygen So long charging done slow rate C/3 less gas can reabsorbed within system Overcharging characterized release oxygen rate too high reabsorption hence increase pressure point cell vented oxygen permanently lost system loss oxygen reduces cell capacity avoid overcharging fast chargers spec ify used discharged cells include atimer cuts off less 100% full recharge discharged cell people insist having possible coulomb cells will add VDD voltage drop detector Most cells will show drop ter minal voltage enter overcharge So VDD circuits added extra expense pro tect overcharging Next month will discuss some real-life charg ers fast quick trickle persuasions Dream Field/Larsen Continued page 39 Beresford Republic sent reporter/photog rapher fun fly two press releases photos have sibce printed willing enthusiastic support Mayor Muller city council city employees has extremely encourag ing time flying fields becom ing harder obtain keep its refresh ing see what rural community can itself goal providing recrea tion its citizens city Beresford has developed free site area RC fliers clubs would willing pay dearly Wed have satisfied simply place fly So deluxe field appearedand few short weekswe elated Beresford Area Radi6 Flyers AMA Chapter 2577 chartered March 31 1989 club provides supervision field well AMA-sponsored liability surance liability question reservation city fathers expressed about entire project AMA inApril 1990 145 OR Get RCDs New 1991-Ready receiver THE PIPER BRAVE scale model Pipers latest Ag plane t wing spafi 30-33 lbs 5 cc power lb payload ational flaps hopper door onal Spreader Kit formed aluminum landing gear rglass cowls um-formed canopy tucted extruded foam ply hardwood e BRAVE95 OPTIONAL $ 1fl95 NOt moer l actuallyKIT$269SPREADER SEND $100 FOR CATALOG OFQ /4/RT 1 NEODESHA KS 66757 SAC KITS AND ACCESSORIESN~316 325-2821 Free Shipping Kit OrdersScott Airplane CompanyVISA /MASTERCARD
Edition: Model Aviation - 1990/04
Page Numbers: 36, 37, 144, 145
George M Mye D 7adiomchnque ABSTRACT Battery charger basics CARING Nicad1 batteriesPart kinds advice about caring Ni cads 11 call Ni-Cds usual editorial style RMcM peo ple selling battery-care devices Some people re charge batteries put use Other people charge regular inter vals whether need Still others keep charged time trickle chargers Everybody succeeds Whos right nickel-cadmium Ni-Cd cell very toler ant abuse neglect makes hard define wrong answers Its service life mea sured terms available discharge/recharge cy cles exceeds needs Rightness deter mined conditions under batteries used example pick up por table telephone expect work immedi ately Portable telephones have rechargeable bat teries kept trickle charger Lets answer some reader questions 1 Q Whats difference between cell battery A cell single energy storage unit has two electrical terminals called positive tive - shows characteristic volt age charged characteristic voltage Ni-Cd cell 125 volts DC lead-acid cell 15 volts characteristic voltage makes easy differentiate various types cells resorting cutting open kinds cells some recharge able others A battery electrically connected group cells RC service typical see four cells used flight packs airplane eight cells inside transmitters although other numbers can beand sometimes areused battery fitted cable plug installed shrink wrap and/or container some kind call battery pack simply pack 2 Q What about C numbers A cell described amount en ergy will store called capacity indicated capital C common cells used RC service about size common AA pencell will store 550 milliamp-hours en ergy hence C mAb mAh iamps x hours will have noticed electrical energy stored cell has dimension current flow over time Amperes measure rate current flow milliamp 1/1000 ampere 550-mAh cell will deliver 550/1000 amp about /2 amp about hour Does mean will also deliver 550 amps 1/1000 hour Almost exactly internal connec tions would probably blow Out tried de liver much current Besides limit extent chemical reactions af 36 Model Aviation Ulu dii Fully di rate y ter providing electricity being ex tracted inside cell such short time course youre talking about explosion long time ago somebody decided nickelcadmium cells should discharged end test voltage I VDC volts direct cur rent current drain should chosen would no appreciable heating cell Given construction cells day discharge current set took two hours get end test voltage So C rating really saying can draw 275 mA two hours bring new freshly charged 550-mAb cell back down 11 VDC draw current cell rated 550 mAh rate faster 275 mA en ergy available work will less rated capacity because some energy will lost heating cells energy won available doing external work higher rate draw energy en ergy goes heat less available work usual Electric airplane setup discharges 1 200-mAh battery about eight minutes can calculate current drawn about 9 amps 12 x 60/8 9 can feel cells get warm Thats Electric airplanes have cooling vents o hou l1O long time recoverable energy turn motor 3 Q What about memory loss capacity Nickel-cadmium batteries develop memory normal RC service What will store little less charge time recharged Eventually time different various designs differ ent ways batteries used battery pack will able hold about half what could hold new Battery manufacturers con sider drop half rated capacity end useful life fly weekends recharge before after flying should take about 10 years reach level maybe longer 4 Q lost-capacity fix observe Ni-Cds have lost some capacity discharge 1 s per cell 44 VDC four-cell flight pack 88 VDC eight-cell transmitter pack can discharge easily simply attaching 10-ohm 10-watt resistor between inals Record time takes drop cell voltage 11 VDC Next recharge usually best re charge slow rate first time Discharge measure time again Recharge again can re charge rates up value C means battery constructed C mAh 70 Froehlkh Farm Rd Hicksville NY 11801 PROCEOL salable vents reclit tir nittoff bat inside cag same kind argument applies recharg ing will discuss later Energy goes heating cells during recharge QU Y ana r VOL chargd cells can recharged rate 550 mA Re peat procedure five times task can simplified use Ace R/C Digipace CaRa Automatic Cycler-Charger similar de vices record battery capacity time run discharges may see pack held 50% rated capacity before fix holds 75% 95% afterward recovery normal will last Note pack usually will recover 100% capac ity New packs will always hold used packs Thats can buy used packs people race electric autosvery cheaply packs wont win races will still fly plane very nicely years started 50% rated capacity did see recovery cells should discarded 5 Q about neglect factor Cells left idle long time like over winter will accept full charge first time recharged Cycle above will recover As example recently reactivated some carpet racers children used play cars have packs six 1200-mAb cells power packs have idle least 10 years surprised find volt meter showed some voltage pack tested six packs typical test showed 10 min utes after first charge 30 minutes after sec ond 60 after third 80 after fourth 90 after fifth little exercise arithmetic shows 90 minutes discharge average 8 volts 10-ohm resistor equals about 1200 mAh six idle packs recovered rated capacity five cycles new used hold up 10% rated capacity tests recharging done rate 900 mAh about 90 minutes using fast charger VDD voltage-drop detection also known peak detection 6 Q about overcharging factor A According friend Larry Sribnick president SR Batteries Ni-Cd battery packs RC service will die repeated over charging see evidence moment take pack apart seal end over charged cell will have white green brown powder grooves powder shows plastic seal under end cap has punc tured Most often puncture due excessive gas pressure case brought about over chargingparticularly high rates Once seal has punctured tiny bit dampness inside released causes kinds bad things corrosion wire pack plug inside wire nsulation cant see Clear evi lence corrosion will found ry solder old wire onto new cell find hat cant make solder stick really bad ases pins battery pack plug will cor rode usually green right through gold plat ing Replace battery cable whenever re place battery 7 Q Which right charger use Simple Use charger came system Overcharging likely hap pen use fast chargers kind recharge cell less hour Continued page 144 ELIMI4TE COMPETITIO April 1990 37 flV71/\F S PROUD r2LTLAJL-AU\ATO ANNOUNCE THE WORLDS SMALLEST ON-BOARD GLO-SWITCH WIRE DIRECT OR Y INTO ANY RECEIVER OUTPUT INCLUDES REVERSING SWITCH ADJUSTABLE 0N POINT AND LED INDICATOR HANDLES 0 TO 12 VOLTS AT UP TO 10 AMPS lf4cc aedad46te ae - 464 a4/ CALL OR WRITE FOR MORE INFO JOMAR PRODUCTS 513-474-0985 2028 Knightsbridge Dr Cinti OH 45244 ACTUAL SIZEI PERFECT PATTERNS Fly perfect patterns time F&Es very affordable fiberglass-and-foam pattern planes Vertigo II oldie goodie 65 span 50 fuselage 600 l wing area Designed 60 power Trike gear Kit lA-i 038 $10995 plus shipping NPhoenix V VI proven trophy-winners board renowned Don Lowe Choose 3 sizes power requirements suit own competitive needs Phoenix V 40 Kit #A-1026 $8995 Phoenix V 60 Kit #A-1027 $9995 Phoenix VI 80 Kit #A-1028 $10995 plus shipping Cure-Air aerobat anhedral 64 span 680 l wing area Special anhedral stabs make Cure-Air behave like dream t side up upside down 60 power Kit lA-i 006 $10995 plus shipping F8E kits feature precision-molded fiberglass fuselages balsa-covered foam wings reduced weight Write call FREE catalog pattern planes stand-off scale current classic warbirds trainer lodayl 1836 Stout Drive inster PA 18974 675-9882 Dler inquii invited SHORT KiTS INCLUOt STYROFOAM WING CORES CANOPIES COLNES PLANS ENGINE MOUNTS PIREWALLS MOLDED MISC PARTS SOME HARDWARE AND MATERIALS LIST FOR BALSA AND ADDITIONAL OFF THE SHELF ITEMS AMMO ZERO SR SPAN 3750 PAD TOMAHAWE 55SPAN3750P3R AIRACORRA 55SPAN3750 P510 MUSTANG 54SPAN37 50 S COOL FOLGORE SRSPAN3750YR FOCEE WOLF 1W 34 SPAN 3730 A26 INVADER 65 SPAN . SAPSr~ P3e LIGHTNING 70 SPAN . 74 95 FAA COeSAIR 56 SPAN . 44 PS11IE~ ORDRRIPdG SEND CHECK OR MONEY CR009 FOR REQUIRED ARROUNT PLES $450 PER KIT CANADIANS ADD 3750 ILEINOIS RESIDENTS ADD RVS% YAK WING Mfg 306 E Simmons Galesburg IL 61401 DUAL STRUT NICKEL PLATED NOSE GEAR H 9 Fults Tooling PO Box 95 Champaign IL 618241 Safety/Preston Continued page 141 18 stated boy play ing model airplane garage home lit disposable lighter melt fuel tube model lighter ignited fumes nearby fuel can caused explosion newspaper articles did identify model Pauls accompanying let ter said believed model question RTF ready-to-fly-7--Ed Control Line plane appears good example introduce son hobby Have safe month Radio Technique/Myers Continued page 37 overntght charger can overcharge keep putting back take out Chargers rated current de liver tong takes recharge battery So know what he/she ing Simple answer Use ammeter cut wires charger connect cut ends ammeter nor cut other wtre charger puts out 45 55 mA what get chargers come RC set would rated C/tO charging AA-sized pencell pack Typi cally such batteries will constructed cells rated between 450 550 mAh So C di vided charging current equals 450/45 50/55 sed way referred C/tO charger overnight charger will see shortly Now very same charger used charge lOO-mAH micro-pack would called what Class Thats right would C/2 charger 100/50 w plug same charger 4000-mAb D-cell what have Obviously its 4000/50 ould called C/80 charger care long time ago somebody discovered C/tO charger could left connected dis charged cell overnight cell would fully charged morning based turn printer airfoil plotter with.. FOILED AGAIN! C PLOT AIRFOILS IN ANY CHORD UP TO 24 INCHES MODIFY ThICKNESS CAMBER & TRAILING EDGE PLOT SKIN THICKNESS FOR SHEErED WINGS ENTER DATA EASILY VIA INTELLIGENT EDITOR USER-FRIENDLY MENU-DRIVEN OPERATION INCLUDES 18-PAGE ILLUSTRATED USER MANUAL $3995 RRURPCI7/TM,ER LNmpw.wMdaep. AdAW5S2533Au CYGNET Software 24843 Del Prado #141b Dana Point CA 92629 eight-hour workday really closer nine hours long take account lunch washup couple coffee breaks So overnight charger born Overnight means something order 15 hours charging C/tO Thats overcharge modern Ni-Cds toler ate little overcharge helps ensure cells come same final voltage called leveling pack should bear mind basic assumption pack fully discharged start 15-hour re charge should also remember Ni-Cd batteries last long timebut forever tI observed charging C/to could go over weekend damaging cells somebody got busy another job found cell left connected C/tO charger long time months would show signs overcharging left connected C/SO charger would retain its charge suffering bad effects overcharging trickle charger born Battery packs must fully charged before attached trickle charger because proper trickle-charging rate fast enough make up tosses caused internal chemistry called self-discharge trickle charger puts out enough current recharge discharged pack batteries could damaged over long time overcharging Going other direction somebody got im patient After ruining few good cells found charging C/3 rate recharged cells three four hours producing signs overcharging quick charger born Some really impatient people wanted get job done no time So dump chargers invented Cells began blow up havent lived until youve seen seated D-size NiCd cell like telephone company uses ex plode like hand grenade Cells made consumer market have vents prevent such explosions connecting single Ni-Cd cell directly 12-volt battery order shock charge can have se rious consequences medical insurance Like Russian roulette get away until dont Cooler heads prevailed some complicated solutions found Internal changes geome try chemistry created fast-charge cells have spring-loaded resealable vents can recharged 15 minutes 4C price Fast-charge cells will dis charge themselves very quickly fastcharge cells will ruined severely overcharge time vent opens cell looses some electrolyte thereby losing capac ity 144 Model Aviation Farnsworth & ElroyInc WHATIWILL YOU DO FOR 1991 Trushjur turrent system hanes can still use present radio systems RCDsPLATINUM GRADE AM FM FCC/AMA listed 1991 ivers fit right R/C systems Fly safely bullet-proof receivers NOW D RCD 100* LI RCD 150* LII RCD200* LI RCD300* Futaba GAM Futaba JAM Futaba J FM Alrtronks AM *Must specify channel# order ORDER BY PHONE CA 800 822-1688 LI RCD 400* Airironics FM US 800 228 -3237 ONLY $59 96 0 2131 Old Oakland Rd Son Jose 95131 1578 should mention point rechargeable cells electrochemical devices reversible chemistry within cell permits accurnula tion release electrical energy chemis try depends r solution potassium hy droxide electrolyte re sides blotter separates plates electrochemistry occurs charging pro cess releases gaseous oxygen So long charging done slow rate C/3 less gas can reabsorbed within system Overcharging characterized release oxygen rate too high reabsorption hence increase pressure point cell vented oxygen permanently lost system loss oxygen reduces cell capacity avoid overcharging fast chargers spec ify used discharged cells include atimer cuts off less 100% full recharge discharged cell people insist having possible coulomb cells will add VDD voltage drop detector Most cells will show drop ter minal voltage enter overcharge So VDD circuits added extra expense pro tect overcharging Next month will discuss some real-life charg ers fast quick trickle persuasions Dream Field/Larsen Continued page 39 Beresford Republic sent reporter/photog rapher fun fly two press releases photos have sibce printed willing enthusiastic support Mayor Muller city council city employees has extremely encourag ing time flying fields becom ing harder obtain keep its refresh ing see what rural community can itself goal providing recrea tion its citizens city Beresford has developed free site area RC fliers clubs would willing pay dearly Wed have satisfied simply place fly So deluxe field appearedand few short weekswe elated Beresford Area Radi6 Flyers AMA Chapter 2577 chartered March 31 1989 club provides supervision field well AMA-sponsored liability surance liability question reservation city fathers expressed about entire project AMA inApril 1990 145 OR Get RCDs New 1991-Ready receiver THE PIPER BRAVE scale model Pipers latest Ag plane t wing spafi 30-33 lbs 5 cc power lb payload ational flaps hopper door onal Spreader Kit formed aluminum landing gear rglass cowls um-formed canopy tucted extruded foam ply hardwood e BRAVE95 OPTIONAL $ 1fl95 NOt moer l actuallyKIT$269SPREADER SEND $100 FOR CATALOG OFQ /4/RT 1 NEODESHA KS 66757 SAC KITS AND ACCESSORIESN~316 325-2821 Free Shipping Kit OrdersScott Airplane CompanyVISA /MASTERCARD