ABSTRACT Polks Challenger 550 PCM radio system BIG NEWS Polks now moving toward PCM line its radio gear has good move because PCM offers better performance several levels I PCM makes significant improvement re sistance forms interference due way computers PCM receiv ers use sample-and-hold compare new informa tion old information detect interference 2 Most PCM systems Polks included use Hold feature provide failsafe set posi tions servos advantage over pulse-width systems common AM FM sets almost always go hard over toward short-pulse end servo travel whenever interference occurs what causes AM/FM systems generate snap-roll-and-spindown situationsomething us familiar Depending nature failsafe program duration interfer ence PCM-guided airplane should either keep doing what doing settle ground low throttle either case interference goes away regain normal system operation recover controlled flight spin 3 The PCM systems market wider choice lower prices first item available Polks all-PCM line Challenger 550 five-channel PCM system consists metal-cased trans mitter receiver full Ni-Cd battery packs charger flag servo trays extra servo arms three servos $21995 Buy two ex tra servos $1495 can use full system right start transmitter fea tures servo reversing five channels dual rates aileron elevator Mode 2 panel meter control sticks having adjustable length tension PCM computer system features what called Variable Hold & Failsafe works like a Interference lasting less 04 seconds servos hold last position interference lasts variable feature means interference lasts shorter time 03 seconds example servos stay put length time probably wont notice what used called glitches b Interference lasts 04 seconds servos go preprogrammed failsafe posi tion first 008 seconds servos stay put go failsafe position remainder time interference lasts can program receivers computer 36 Model Aviation George M Mye D Radio Thchnque 70 Froehlkh Farm Rd Hicksvllle NY 1801 Device left servo-testing fixture built George Giant Scaler Jerry Smith years ago still use Servo under test under big pointer receiver upper right battery pack lower right Photo right reveals circuit board Polks Challenger 550 PCM receiver Comparing Polks old #402 new #422 servos photo left note new servo shallower under mounting lugs Photo right shows difference between new 1 old R servo plugs theyre interchangeable New servo left time choice failsafe servo positions simply pushing button transmitter sys tem operating example might take plane air bring throttle back idle trim plane wide slightly de scending circle Pressing button plane circling stores program receivers computer either case interference goes away should take time interval equivalent about two frames frame time interval computer performs complete cycle program executionEdor about 007 sec servos start back toward positions commanded transmitter sticks have go other end travel could take another 02 seconds battery voltage level six volts So will out control 3/10th second longer interference lasts about same non-PCM system improvement over first PCMs market system tested contains dual-conversion receiver similar found last years Challenger 720 system PCM com puter added shows very good performance made better PCM receiver has working range 28 70 volts seven-volt rating means receiver will work five-cell Ni-Cd pack fastest speed great est torque servos though FM system receiver uses automatic gain control system called Automatic Gain Down What does reduce amplification received signals control signal strong has effect tun ing out other signals might trying inter fere control DC-to-DC converter receiver makes very stable performance battery volt age varies over range 28-70 volts Im sure put permit use alkaline batteries receiver batteries cars boats strongly advise fly four-alkaline-pencell battery box times have switched flashlight found didnt light So bang around little does light Well same thing can happen airplane call flashlight syndrome cant ar gue thought better performance everybody including people using Ni-Cd re Continued page 147 Dont Hornswoggled JUSI horn5 Th new TherodS aircraft ughro reciseco matter Psdered ntrusttheiroP lifeline5 YOUntrOl yOU re can b Ceratloflye theshrted WI control caflte ontarlyIPU 0ds0d ofe toHorr~ng ball link 10thth WIbha Robart thOut n9ccurate onafteronWlffers al ball link en les what applicatl bart r 0fleyon need hB an horn elimin d WhY waste ~en effiCfltCsystem WyOU can money Roba save time K Control Horns Ball LIn Leader small Airfoil Technology Spinners New Master Airscrew series spinners four sizes Featuring aluminum backplate true running cones made red black engineering grade nylon strength resist starter burn spinners have excellent balance custom fit Available black red sizes 2 2See Hobby Dealer 21/2for MASTER AIRSCREW propellers accessories WINDSOR PROPELLER CO 3219 Monier Circle Rancho Cordova CA 95742 .. $325 375 425 .. 475 October 1989 37 Rear view Polks Challenger 550 trans mitter back case removed Note simple layout Ni-Cd pack bottom five servo-reversing switches two rotary dual-rate adjusting pots left rt Mfg 1988PO Box 1247 St Charles Illinois 60174 Master Airscrew propellers difference 76 dB equates power ra tio 57that airplane permitted emit 57 times much sonic power permitted under old standard current AMA recommendation 88 dB tougher new FAI rule Thats power ratio 76 am surprised lack consistency between AMA FAI Because have sound meter know noise propagation 100 dB 9 ft very common flying field muf flers Ive also discovered fourcycle engines sound tolerably quiet ear measure 100 dB up range Obviously subjective evaluation noise can deceptive four-cycle en gine sounds less objectionable two cycle engine yet registers almost high big ignition engine too sounds tamer its high readings meter would suggest Additionally frequency spectrum af fects perception noise see arti cle Sound Related Flying Sites No vember 1987 MA fact deserves careful thought respect relations public doubt noise levels seeing todays muffled engines pose real threat hearing especially since time standing quite some dis tance models Thank heavens mufflers After 50 years listen ing model engines mostly unmuffled hearing quite impaired high fre quency end age might have something Finally since propeller sig nificantly increases sound output use larger slower props should help allay noise problem Noisehow produce mea sure itis becoming major issue hobby today Coping problem intelligent way demands some effort means familiarizing ourselves rele vant technical terminology educating ourselves about factors influence sound emission article written purpose mind Radio Technique/Myers Continued page 37 ceiver batteries will result presence DC-DC converter receiver batteries making contact low-voltage alarm LVA system also cluded receivers PCM computer battery voltage drops below 28 volts throttle servoand throttle servogoes preset position stays typographic error receiver continues func tion down 28 volts advertised thats LVA cuts may fine get ting everything possible out alkaline batteries its dangerously low Ni-Cds think Ive got Polks convinced move trip point up around 47 volts will enough charge left Ni-Cds land safely subject batteries Chal lenger 550 manual says Transmitter 96-108 VDC 8 9 Nicad tin batteries Mine came usual Polks nine-pencell Ni-Cd pack transmitter four-pencell Ni-Cd pack receiver Transmitter operating cur rent measured 120 mA predicts about four hours operating timebetter PCM transmitters Output power looks like about 550 milliwatts Receiver drain idle five servos measured 60 mA battery charge should last about four hours ordinary service Frequency agility plug-in module transmitter inexpensive receivers make easy field changes frequency within 72 MHz band make swap field should check ground range adequate fly time no modules Ham CB bands well does work Bob Aberle t did field test system performed very well type testing last discussed May 1988 column discussed length January 1986 column results testing follows M200 adjacent channels 20 kHz Gold FM old AM ilver AM 0 kHz Gold FM Gold AM ilver AM djacent-channel performance excellent 1989 environment Polks still working develop 'bulletproof receiver 1991 turns out job some folks expectedContinued page 148 October 1989 147 ALTIMETER PERKIN AVIONICS PC-i micro sized altimeter has designed specifically RIO soaring enthusiast high tech instrument comes ready go minimal installa tion required MEASURES ALTITUDE IN 10 FT INCREMENTS AND STORES IN MEMORY HIGHEST AGL ON EACH FLIGHT WEIGHS LESS THAN 4 OZ LED DISPLAY CAN BE MOUNTED SEPARATELY FOR EASY ACCESS AUTOMATICALLY ADJUST FOR TEMPERATURE VARI ANCE AND STARTING POINT ABOVE SEA LEVEL NO BATTERY DRAIN ON FLIGHT PACK NI-CAD Introductory price $11500 no shipping charge also PERKIN AVIONICS soon released MISSILE LOCK airborne electronic weap system information either exciting new products send $300 sase C S PO Box 396 Ellenwood GA 30049 Call404 366-1591 THE WORLDS FINEST SMALL ENGINES M200 Flight Line Simulation 20 kHz Gold FM/Gold FM 36 Gold FM/Gold AM 36 Silver FM/ Silver AM 36 40kHz Gold FM/Gold FM 36 Gold FM Gold AM 36 Silver FM/Silver AM 36 Something good going FLS test dont know what PCM computer ap parently treats intermodulations same way way better older sets servos rated six volts four AA al kaline batteries specifications However Charles Hampton has flying HS-402 servos over year five-cell Ni-Cd pack has no troubles Hitec needs rewrite its specifi cation include 70 volts five-cell Ni-Cd pack slim S plug compatible last years Molex will used 1989 aircraft ra dios new HS-422 servo becomes standard aircraft radio servo year HS-422 projects / less below mounting plane does previous HS-402 uses custom chip like Futaba does features new motor very smooth gear train faster able work down 28 volts output shaft supported twopiece metal bearings above below final gear should no trouble wearing oval holes case happened old days plastic-to-plastic bear ings HS-XXX servos pulse-width controlled have 155-millisecond neutral practi cally servo should work radio worth knowing servos work great five-cell Ni-Cd packs give torque faster operation found little surgery plastic plugs would let use Airtronics servo Challenger 550 receiver Depending sequence - al wires plugs other manufacturers servos may also work bench counted 108 steps servo responding 300 full swing aileron stick High Rate count reduced dual-rate lever 31 steps full range its trim lever count affected dual-rate switch function PCM computer quite fast seems use eight-bit words Since servo throw 300 equates step per /20 motion Reso lution centering good Recentering after working stick oppo site sides usually exact never worse /2 0 out place corresponds t PCM code Using variable speed motor-driven device work landing gear switch back forth watching long pointer move over large pro tractor detect servo could no longer keep up input movement determined system can follow 120 cycles per minute four-cell Ni-Cd receiver pack servo alone can keep up 140 cycles per minute 600 travel better servos pwn have say system fast enough anybody charger supplied Challenger 550 puts Out 108 volts 50 mA 57 volts 50 mA marked will have supply own charger want use five-cell re ceiver pack frequency flag supplied Polks also nice Fun FIy/Kruse Continued page 47 David Narance Marion OH Henry M Neweome Bowling Green OH Fran cis H Nixon Lake Charles LA Frank V Noll Dayton OH Roger G Ormson Barron WI Santiago Panzardi Fairborn OH Antony Peters New York NY Phillip W Pratter Jamestown OH Timothy P Procuniar Beaverereek OH Joseph L Re inhard Columbus OH Donald H Ross Cresskill NJ James M Ruley Spring field OH Dennis F Sadowski Dayton OH Eugene P Schepers Upper Mont clair NJ Pete Schmidt Grand Rapids MI Albert Seidowski Cleveland OH Robert J Smyth Cincinnati OH Michael R Still Kokomo IN Glenn Stucker West Chester OH Darren B Suter Paden City WV Clifford J Tacie Mt Clemens MI Nur I Taib Bloomington IN Maurice C Tay lor Ohio City OH David R Thacker Hu Heights OH Bruce Anthony Tharpe Montezuma IA Jim Tibbitts Holland MI Gary E Underhill MD Evansville IN Thomas B Vandegrift East Berne NY Charles C Vermillion Marion IN Kirk R Voeckel Tarentum PA Gary R Wild Greenwood IN Lawrence M Wil son North Vernon IN Harold W Wint ers New Providence NJ Earl F Witt Chambersburg PA Raymond J Woodall New Kensington PA Robert S Wroblew ski Livonia MI 148 Model Aviation 7U rn-A, 6F700705/22 RF90O 3/ 6 08 Fults Tooling P0 Box 95 champaign IL PERKIN VI0N /
Edition: Model Aviation - 1989/10
Page Numbers: 36, 37, 147, 148
ABSTRACT Polks Challenger 550 PCM radio system BIG NEWS Polks now moving toward PCM line its radio gear has good move because PCM offers better performance several levels I PCM makes significant improvement re sistance forms interference due way computers PCM receiv ers use sample-and-hold compare new informa tion old information detect interference 2 Most PCM systems Polks included use Hold feature provide failsafe set posi tions servos advantage over pulse-width systems common AM FM sets almost always go hard over toward short-pulse end servo travel whenever interference occurs what causes AM/FM systems generate snap-roll-and-spindown situationsomething us familiar Depending nature failsafe program duration interfer ence PCM-guided airplane should either keep doing what doing settle ground low throttle either case interference goes away regain normal system operation recover controlled flight spin 3 The PCM systems market wider choice lower prices first item available Polks all-PCM line Challenger 550 five-channel PCM system consists metal-cased trans mitter receiver full Ni-Cd battery packs charger flag servo trays extra servo arms three servos $21995 Buy two ex tra servos $1495 can use full system right start transmitter fea tures servo reversing five channels dual rates aileron elevator Mode 2 panel meter control sticks having adjustable length tension PCM computer system features what called Variable Hold & Failsafe works like a Interference lasting less 04 seconds servos hold last position interference lasts variable feature means interference lasts shorter time 03 seconds example servos stay put length time probably wont notice what used called glitches b Interference lasts 04 seconds servos go preprogrammed failsafe posi tion first 008 seconds servos stay put go failsafe position remainder time interference lasts can program receivers computer 36 Model Aviation George M Mye D Radio Thchnque 70 Froehlkh Farm Rd Hicksvllle NY 1801 Device left servo-testing fixture built George Giant Scaler Jerry Smith years ago still use Servo under test under big pointer receiver upper right battery pack lower right Photo right reveals circuit board Polks Challenger 550 PCM receiver Comparing Polks old #402 new #422 servos photo left note new servo shallower under mounting lugs Photo right shows difference between new 1 old R servo plugs theyre interchangeable New servo left time choice failsafe servo positions simply pushing button transmitter sys tem operating example might take plane air bring throttle back idle trim plane wide slightly de scending circle Pressing button plane circling stores program receivers computer either case interference goes away should take time interval equivalent about two frames frame time interval computer performs complete cycle program executionEdor about 007 sec servos start back toward positions commanded transmitter sticks have go other end travel could take another 02 seconds battery voltage level six volts So will out control 3/10th second longer interference lasts about same non-PCM system improvement over first PCMs market system tested contains dual-conversion receiver similar found last years Challenger 720 system PCM com puter added shows very good performance made better PCM receiver has working range 28 70 volts seven-volt rating means receiver will work five-cell Ni-Cd pack fastest speed great est torque servos though FM system receiver uses automatic gain control system called Automatic Gain Down What does reduce amplification received signals control signal strong has effect tun ing out other signals might trying inter fere control DC-to-DC converter receiver makes very stable performance battery volt age varies over range 28-70 volts Im sure put permit use alkaline batteries receiver batteries cars boats strongly advise fly four-alkaline-pencell battery box times have switched flashlight found didnt light So bang around little does light Well same thing can happen airplane call flashlight syndrome cant ar gue thought better performance everybody including people using Ni-Cd re Continued page 147 Dont Hornswoggled JUSI horn5 Th new TherodS aircraft ughro reciseco matter Psdered ntrusttheiroP lifeline5 YOUntrOl yOU re can b Ceratloflye theshrted WI control caflte ontarlyIPU 0ds0d ofe toHorr~ng ball link 10thth WIbha Robart thOut n9ccurate onafteronWlffers al ball link en les what applicatl bart r 0fleyon need hB an horn elimin d WhY waste ~en effiCfltCsystem WyOU can money Roba save time K Control Horns Ball LIn Leader small Airfoil Technology Spinners New Master Airscrew series spinners four sizes Featuring aluminum backplate true running cones made red black engineering grade nylon strength resist starter burn spinners have excellent balance custom fit Available black red sizes 2 2See Hobby Dealer 21/2for MASTER AIRSCREW propellers accessories WINDSOR PROPELLER CO 3219 Monier Circle Rancho Cordova CA 95742 .. $325 375 425 .. 475 October 1989 37 Rear view Polks Challenger 550 trans mitter back case removed Note simple layout Ni-Cd pack bottom five servo-reversing switches two rotary dual-rate adjusting pots left rt Mfg 1988PO Box 1247 St Charles Illinois 60174 Master Airscrew propellers difference 76 dB equates power ra tio 57that airplane permitted emit 57 times much sonic power permitted under old standard current AMA recommendation 88 dB tougher new FAI rule Thats power ratio 76 am surprised lack consistency between AMA FAI Because have sound meter know noise propagation 100 dB 9 ft very common flying field muf flers Ive also discovered fourcycle engines sound tolerably quiet ear measure 100 dB up range Obviously subjective evaluation noise can deceptive four-cycle en gine sounds less objectionable two cycle engine yet registers almost high big ignition engine too sounds tamer its high readings meter would suggest Additionally frequency spectrum af fects perception noise see arti cle Sound Related Flying Sites No vember 1987 MA fact deserves careful thought respect relations public doubt noise levels seeing todays muffled engines pose real threat hearing especially since time standing quite some dis tance models Thank heavens mufflers After 50 years listen ing model engines mostly unmuffled hearing quite impaired high fre quency end age might have something Finally since propeller sig nificantly increases sound output use larger slower props should help allay noise problem Noisehow produce mea sure itis becoming major issue hobby today Coping problem intelligent way demands some effort means familiarizing ourselves rele vant technical terminology educating ourselves about factors influence sound emission article written purpose mind Radio Technique/Myers Continued page 37 ceiver batteries will result presence DC-DC converter receiver batteries making contact low-voltage alarm LVA system also cluded receivers PCM computer battery voltage drops below 28 volts throttle servoand throttle servogoes preset position stays typographic error receiver continues func tion down 28 volts advertised thats LVA cuts may fine get ting everything possible out alkaline batteries its dangerously low Ni-Cds think Ive got Polks convinced move trip point up around 47 volts will enough charge left Ni-Cds land safely subject batteries Chal lenger 550 manual says Transmitter 96-108 VDC 8 9 Nicad tin batteries Mine came usual Polks nine-pencell Ni-Cd pack transmitter four-pencell Ni-Cd pack receiver Transmitter operating cur rent measured 120 mA predicts about four hours operating timebetter PCM transmitters Output power looks like about 550 milliwatts Receiver drain idle five servos measured 60 mA battery charge should last about four hours ordinary service Frequency agility plug-in module transmitter inexpensive receivers make easy field changes frequency within 72 MHz band make swap field should check ground range adequate fly time no modules Ham CB bands well does work Bob Aberle t did field test system performed very well type testing last discussed May 1988 column discussed length January 1986 column results testing follows M200 adjacent channels 20 kHz Gold FM old AM ilver AM 0 kHz Gold FM Gold AM ilver AM djacent-channel performance excellent 1989 environment Polks still working develop 'bulletproof receiver 1991 turns out job some folks expectedContinued page 148 October 1989 147 ALTIMETER PERKIN AVIONICS PC-i micro sized altimeter has designed specifically RIO soaring enthusiast high tech instrument comes ready go minimal installa tion required MEASURES ALTITUDE IN 10 FT INCREMENTS AND STORES IN MEMORY HIGHEST AGL ON EACH FLIGHT WEIGHS LESS THAN 4 OZ LED DISPLAY CAN BE MOUNTED SEPARATELY FOR EASY ACCESS AUTOMATICALLY ADJUST FOR TEMPERATURE VARI ANCE AND STARTING POINT ABOVE SEA LEVEL NO BATTERY DRAIN ON FLIGHT PACK NI-CAD Introductory price $11500 no shipping charge also PERKIN AVIONICS soon released MISSILE LOCK airborne electronic weap system information either exciting new products send $300 sase C S PO Box 396 Ellenwood GA 30049 Call404 366-1591 THE WORLDS FINEST SMALL ENGINES M200 Flight Line Simulation 20 kHz Gold FM/Gold FM 36 Gold FM/Gold AM 36 Silver FM/ Silver AM 36 40kHz Gold FM/Gold FM 36 Gold FM Gold AM 36 Silver FM/Silver AM 36 Something good going FLS test dont know what PCM computer ap parently treats intermodulations same way way better older sets servos rated six volts four AA al kaline batteries specifications However Charles Hampton has flying HS-402 servos over year five-cell Ni-Cd pack has no troubles Hitec needs rewrite its specifi cation include 70 volts five-cell Ni-Cd pack slim S plug compatible last years Molex will used 1989 aircraft ra dios new HS-422 servo becomes standard aircraft radio servo year HS-422 projects / less below mounting plane does previous HS-402 uses custom chip like Futaba does features new motor very smooth gear train faster able work down 28 volts output shaft supported twopiece metal bearings above below final gear should no trouble wearing oval holes case happened old days plastic-to-plastic bear ings HS-XXX servos pulse-width controlled have 155-millisecond neutral practi cally servo should work radio worth knowing servos work great five-cell Ni-Cd packs give torque faster operation found little surgery plastic plugs would let use Airtronics servo Challenger 550 receiver Depending sequence - al wires plugs other manufacturers servos may also work bench counted 108 steps servo responding 300 full swing aileron stick High Rate count reduced dual-rate lever 31 steps full range its trim lever count affected dual-rate switch function PCM computer quite fast seems use eight-bit words Since servo throw 300 equates step per /20 motion Reso lution centering good Recentering after working stick oppo site sides usually exact never worse /2 0 out place corresponds t PCM code Using variable speed motor-driven device work landing gear switch back forth watching long pointer move over large pro tractor detect servo could no longer keep up input movement determined system can follow 120 cycles per minute four-cell Ni-Cd receiver pack servo alone can keep up 140 cycles per minute 600 travel better servos pwn have say system fast enough anybody charger supplied Challenger 550 puts Out 108 volts 50 mA 57 volts 50 mA marked will have supply own charger want use five-cell re ceiver pack frequency flag supplied Polks also nice Fun FIy/Kruse Continued page 47 David Narance Marion OH Henry M Neweome Bowling Green OH Fran cis H Nixon Lake Charles LA Frank V Noll Dayton OH Roger G Ormson Barron WI Santiago Panzardi Fairborn OH Antony Peters New York NY Phillip W Pratter Jamestown OH Timothy P Procuniar Beaverereek OH Joseph L Re inhard Columbus OH Donald H Ross Cresskill NJ James M Ruley Spring field OH Dennis F Sadowski Dayton OH Eugene P Schepers Upper Mont clair NJ Pete Schmidt Grand Rapids MI Albert Seidowski Cleveland OH Robert J Smyth Cincinnati OH Michael R Still Kokomo IN Glenn Stucker West Chester OH Darren B Suter Paden City WV Clifford J Tacie Mt Clemens MI Nur I Taib Bloomington IN Maurice C Tay lor Ohio City OH David R Thacker Hu Heights OH Bruce Anthony Tharpe Montezuma IA Jim Tibbitts Holland MI Gary E Underhill MD Evansville IN Thomas B Vandegrift East Berne NY Charles C Vermillion Marion IN Kirk R Voeckel Tarentum PA Gary R Wild Greenwood IN Lawrence M Wil son North Vernon IN Harold W Wint ers New Providence NJ Earl F Witt Chambersburg PA Raymond J Woodall New Kensington PA Robert S Wroblew ski Livonia MI 148 Model Aviation 7U rn-A, 6F700705/22 RF90O 3/ 6 08 Fults Tooling P0 Box 95 champaign IL PERKIN VI0N /
Edition: Model Aviation - 1989/10
Page Numbers: 36, 37, 147, 148
ABSTRACT Polks Challenger 550 PCM radio system BIG NEWS Polks now moving toward PCM line its radio gear has good move because PCM offers better performance several levels I PCM makes significant improvement re sistance forms interference due way computers PCM receiv ers use sample-and-hold compare new informa tion old information detect interference 2 Most PCM systems Polks included use Hold feature provide failsafe set posi tions servos advantage over pulse-width systems common AM FM sets almost always go hard over toward short-pulse end servo travel whenever interference occurs what causes AM/FM systems generate snap-roll-and-spindown situationsomething us familiar Depending nature failsafe program duration interfer ence PCM-guided airplane should either keep doing what doing settle ground low throttle either case interference goes away regain normal system operation recover controlled flight spin 3 The PCM systems market wider choice lower prices first item available Polks all-PCM line Challenger 550 five-channel PCM system consists metal-cased trans mitter receiver full Ni-Cd battery packs charger flag servo trays extra servo arms three servos $21995 Buy two ex tra servos $1495 can use full system right start transmitter fea tures servo reversing five channels dual rates aileron elevator Mode 2 panel meter control sticks having adjustable length tension PCM computer system features what called Variable Hold & Failsafe works like a Interference lasting less 04 seconds servos hold last position interference lasts variable feature means interference lasts shorter time 03 seconds example servos stay put length time probably wont notice what used called glitches b Interference lasts 04 seconds servos go preprogrammed failsafe posi tion first 008 seconds servos stay put go failsafe position remainder time interference lasts can program receivers computer 36 Model Aviation George M Mye D Radio Thchnque 70 Froehlkh Farm Rd Hicksvllle NY 1801 Device left servo-testing fixture built George Giant Scaler Jerry Smith years ago still use Servo under test under big pointer receiver upper right battery pack lower right Photo right reveals circuit board Polks Challenger 550 PCM receiver Comparing Polks old #402 new #422 servos photo left note new servo shallower under mounting lugs Photo right shows difference between new 1 old R servo plugs theyre interchangeable New servo left time choice failsafe servo positions simply pushing button transmitter sys tem operating example might take plane air bring throttle back idle trim plane wide slightly de scending circle Pressing button plane circling stores program receivers computer either case interference goes away should take time interval equivalent about two frames frame time interval computer performs complete cycle program executionEdor about 007 sec servos start back toward positions commanded transmitter sticks have go other end travel could take another 02 seconds battery voltage level six volts So will out control 3/10th second longer interference lasts about same non-PCM system improvement over first PCMs market system tested contains dual-conversion receiver similar found last years Challenger 720 system PCM com puter added shows very good performance made better PCM receiver has working range 28 70 volts seven-volt rating means receiver will work five-cell Ni-Cd pack fastest speed great est torque servos though FM system receiver uses automatic gain control system called Automatic Gain Down What does reduce amplification received signals control signal strong has effect tun ing out other signals might trying inter fere control DC-to-DC converter receiver makes very stable performance battery volt age varies over range 28-70 volts Im sure put permit use alkaline batteries receiver batteries cars boats strongly advise fly four-alkaline-pencell battery box times have switched flashlight found didnt light So bang around little does light Well same thing can happen airplane call flashlight syndrome cant ar gue thought better performance everybody including people using Ni-Cd re Continued page 147 Dont Hornswoggled JUSI horn5 Th new TherodS aircraft ughro reciseco matter Psdered ntrusttheiroP lifeline5 YOUntrOl yOU re can b Ceratloflye theshrted WI control caflte ontarlyIPU 0ds0d ofe toHorr~ng ball link 10thth WIbha Robart thOut n9ccurate onafteronWlffers al ball link en les what applicatl bart r 0fleyon need hB an horn elimin d WhY waste ~en effiCfltCsystem WyOU can money Roba save time K Control Horns Ball LIn Leader small Airfoil Technology Spinners New Master Airscrew series spinners four sizes Featuring aluminum backplate true running cones made red black engineering grade nylon strength resist starter burn spinners have excellent balance custom fit Available black red sizes 2 2See Hobby Dealer 21/2for MASTER AIRSCREW propellers accessories WINDSOR PROPELLER CO 3219 Monier Circle Rancho Cordova CA 95742 .. $325 375 425 .. 475 October 1989 37 Rear view Polks Challenger 550 trans mitter back case removed Note simple layout Ni-Cd pack bottom five servo-reversing switches two rotary dual-rate adjusting pots left rt Mfg 1988PO Box 1247 St Charles Illinois 60174 Master Airscrew propellers difference 76 dB equates power ra tio 57that airplane permitted emit 57 times much sonic power permitted under old standard current AMA recommendation 88 dB tougher new FAI rule Thats power ratio 76 am surprised lack consistency between AMA FAI Because have sound meter know noise propagation 100 dB 9 ft very common flying field muf flers Ive also discovered fourcycle engines sound tolerably quiet ear measure 100 dB up range Obviously subjective evaluation noise can deceptive four-cycle en gine sounds less objectionable two cycle engine yet registers almost high big ignition engine too sounds tamer its high readings meter would suggest Additionally frequency spectrum af fects perception noise see arti cle Sound Related Flying Sites No vember 1987 MA fact deserves careful thought respect relations public doubt noise levels seeing todays muffled engines pose real threat hearing especially since time standing quite some dis tance models Thank heavens mufflers After 50 years listen ing model engines mostly unmuffled hearing quite impaired high fre quency end age might have something Finally since propeller sig nificantly increases sound output use larger slower props should help allay noise problem Noisehow produce mea sure itis becoming major issue hobby today Coping problem intelligent way demands some effort means familiarizing ourselves rele vant technical terminology educating ourselves about factors influence sound emission article written purpose mind Radio Technique/Myers Continued page 37 ceiver batteries will result presence DC-DC converter receiver batteries making contact low-voltage alarm LVA system also cluded receivers PCM computer battery voltage drops below 28 volts throttle servoand throttle servogoes preset position stays typographic error receiver continues func tion down 28 volts advertised thats LVA cuts may fine get ting everything possible out alkaline batteries its dangerously low Ni-Cds think Ive got Polks convinced move trip point up around 47 volts will enough charge left Ni-Cds land safely subject batteries Chal lenger 550 manual says Transmitter 96-108 VDC 8 9 Nicad tin batteries Mine came usual Polks nine-pencell Ni-Cd pack transmitter four-pencell Ni-Cd pack receiver Transmitter operating cur rent measured 120 mA predicts about four hours operating timebetter PCM transmitters Output power looks like about 550 milliwatts Receiver drain idle five servos measured 60 mA battery charge should last about four hours ordinary service Frequency agility plug-in module transmitter inexpensive receivers make easy field changes frequency within 72 MHz band make swap field should check ground range adequate fly time no modules Ham CB bands well does work Bob Aberle t did field test system performed very well type testing last discussed May 1988 column discussed length January 1986 column results testing follows M200 adjacent channels 20 kHz Gold FM old AM ilver AM 0 kHz Gold FM Gold AM ilver AM djacent-channel performance excellent 1989 environment Polks still working develop 'bulletproof receiver 1991 turns out job some folks expectedContinued page 148 October 1989 147 ALTIMETER PERKIN AVIONICS PC-i micro sized altimeter has designed specifically RIO soaring enthusiast high tech instrument comes ready go minimal installa tion required MEASURES ALTITUDE IN 10 FT INCREMENTS AND STORES IN MEMORY HIGHEST AGL ON EACH FLIGHT WEIGHS LESS THAN 4 OZ LED DISPLAY CAN BE MOUNTED SEPARATELY FOR EASY ACCESS AUTOMATICALLY ADJUST FOR TEMPERATURE VARI ANCE AND STARTING POINT ABOVE SEA LEVEL NO BATTERY DRAIN ON FLIGHT PACK NI-CAD Introductory price $11500 no shipping charge also PERKIN AVIONICS soon released MISSILE LOCK airborne electronic weap system information either exciting new products send $300 sase C S PO Box 396 Ellenwood GA 30049 Call404 366-1591 THE WORLDS FINEST SMALL ENGINES M200 Flight Line Simulation 20 kHz Gold FM/Gold FM 36 Gold FM/Gold AM 36 Silver FM/ Silver AM 36 40kHz Gold FM/Gold FM 36 Gold FM Gold AM 36 Silver FM/Silver AM 36 Something good going FLS test dont know what PCM computer ap parently treats intermodulations same way way better older sets servos rated six volts four AA al kaline batteries specifications However Charles Hampton has flying HS-402 servos over year five-cell Ni-Cd pack has no troubles Hitec needs rewrite its specifi cation include 70 volts five-cell Ni-Cd pack slim S plug compatible last years Molex will used 1989 aircraft ra dios new HS-422 servo becomes standard aircraft radio servo year HS-422 projects / less below mounting plane does previous HS-402 uses custom chip like Futaba does features new motor very smooth gear train faster able work down 28 volts output shaft supported twopiece metal bearings above below final gear should no trouble wearing oval holes case happened old days plastic-to-plastic bear ings HS-XXX servos pulse-width controlled have 155-millisecond neutral practi cally servo should work radio worth knowing servos work great five-cell Ni-Cd packs give torque faster operation found little surgery plastic plugs would let use Airtronics servo Challenger 550 receiver Depending sequence - al wires plugs other manufacturers servos may also work bench counted 108 steps servo responding 300 full swing aileron stick High Rate count reduced dual-rate lever 31 steps full range its trim lever count affected dual-rate switch function PCM computer quite fast seems use eight-bit words Since servo throw 300 equates step per /20 motion Reso lution centering good Recentering after working stick oppo site sides usually exact never worse /2 0 out place corresponds t PCM code Using variable speed motor-driven device work landing gear switch back forth watching long pointer move over large pro tractor detect servo could no longer keep up input movement determined system can follow 120 cycles per minute four-cell Ni-Cd receiver pack servo alone can keep up 140 cycles per minute 600 travel better servos pwn have say system fast enough anybody charger supplied Challenger 550 puts Out 108 volts 50 mA 57 volts 50 mA marked will have supply own charger want use five-cell re ceiver pack frequency flag supplied Polks also nice Fun FIy/Kruse Continued page 47 David Narance Marion OH Henry M Neweome Bowling Green OH Fran cis H Nixon Lake Charles LA Frank V Noll Dayton OH Roger G Ormson Barron WI Santiago Panzardi Fairborn OH Antony Peters New York NY Phillip W Pratter Jamestown OH Timothy P Procuniar Beaverereek OH Joseph L Re inhard Columbus OH Donald H Ross Cresskill NJ James M Ruley Spring field OH Dennis F Sadowski Dayton OH Eugene P Schepers Upper Mont clair NJ Pete Schmidt Grand Rapids MI Albert Seidowski Cleveland OH Robert J Smyth Cincinnati OH Michael R Still Kokomo IN Glenn Stucker West Chester OH Darren B Suter Paden City WV Clifford J Tacie Mt Clemens MI Nur I Taib Bloomington IN Maurice C Tay lor Ohio City OH David R Thacker Hu Heights OH Bruce Anthony Tharpe Montezuma IA Jim Tibbitts Holland MI Gary E Underhill MD Evansville IN Thomas B Vandegrift East Berne NY Charles C Vermillion Marion IN Kirk R Voeckel Tarentum PA Gary R Wild Greenwood IN Lawrence M Wil son North Vernon IN Harold W Wint ers New Providence NJ Earl F Witt Chambersburg PA Raymond J Woodall New Kensington PA Robert S Wroblew ski Livonia MI 148 Model Aviation 7U rn-A, 6F700705/22 RF90O 3/ 6 08 Fults Tooling P0 Box 95 champaign IL PERKIN VI0N /
Edition: Model Aviation - 1989/10
Page Numbers: 36, 37, 147, 148
ABSTRACT Polks Challenger 550 PCM radio system BIG NEWS Polks now moving toward PCM line its radio gear has good move because PCM offers better performance several levels I PCM makes significant improvement re sistance forms interference due way computers PCM receiv ers use sample-and-hold compare new informa tion old information detect interference 2 Most PCM systems Polks included use Hold feature provide failsafe set posi tions servos advantage over pulse-width systems common AM FM sets almost always go hard over toward short-pulse end servo travel whenever interference occurs what causes AM/FM systems generate snap-roll-and-spindown situationsomething us familiar Depending nature failsafe program duration interfer ence PCM-guided airplane should either keep doing what doing settle ground low throttle either case interference goes away regain normal system operation recover controlled flight spin 3 The PCM systems market wider choice lower prices first item available Polks all-PCM line Challenger 550 five-channel PCM system consists metal-cased trans mitter receiver full Ni-Cd battery packs charger flag servo trays extra servo arms three servos $21995 Buy two ex tra servos $1495 can use full system right start transmitter fea tures servo reversing five channels dual rates aileron elevator Mode 2 panel meter control sticks having adjustable length tension PCM computer system features what called Variable Hold & Failsafe works like a Interference lasting less 04 seconds servos hold last position interference lasts variable feature means interference lasts shorter time 03 seconds example servos stay put length time probably wont notice what used called glitches b Interference lasts 04 seconds servos go preprogrammed failsafe posi tion first 008 seconds servos stay put go failsafe position remainder time interference lasts can program receivers computer 36 Model Aviation George M Mye D Radio Thchnque 70 Froehlkh Farm Rd Hicksvllle NY 1801 Device left servo-testing fixture built George Giant Scaler Jerry Smith years ago still use Servo under test under big pointer receiver upper right battery pack lower right Photo right reveals circuit board Polks Challenger 550 PCM receiver Comparing Polks old #402 new #422 servos photo left note new servo shallower under mounting lugs Photo right shows difference between new 1 old R servo plugs theyre interchangeable New servo left time choice failsafe servo positions simply pushing button transmitter sys tem operating example might take plane air bring throttle back idle trim plane wide slightly de scending circle Pressing button plane circling stores program receivers computer either case interference goes away should take time interval equivalent about two frames frame time interval computer performs complete cycle program executionEdor about 007 sec servos start back toward positions commanded transmitter sticks have go other end travel could take another 02 seconds battery voltage level six volts So will out control 3/10th second longer interference lasts about same non-PCM system improvement over first PCMs market system tested contains dual-conversion receiver similar found last years Challenger 720 system PCM com puter added shows very good performance made better PCM receiver has working range 28 70 volts seven-volt rating means receiver will work five-cell Ni-Cd pack fastest speed great est torque servos though FM system receiver uses automatic gain control system called Automatic Gain Down What does reduce amplification received signals control signal strong has effect tun ing out other signals might trying inter fere control DC-to-DC converter receiver makes very stable performance battery volt age varies over range 28-70 volts Im sure put permit use alkaline batteries receiver batteries cars boats strongly advise fly four-alkaline-pencell battery box times have switched flashlight found didnt light So bang around little does light Well same thing can happen airplane call flashlight syndrome cant ar gue thought better performance everybody including people using Ni-Cd re Continued page 147 Dont Hornswoggled JUSI horn5 Th new TherodS aircraft ughro reciseco matter Psdered ntrusttheiroP lifeline5 YOUntrOl yOU re can b Ceratloflye theshrted WI control caflte ontarlyIPU 0ds0d ofe toHorr~ng ball link 10thth WIbha Robart thOut n9ccurate onafteronWlffers al ball link en les what applicatl bart r 0fleyon need hB an horn elimin d WhY waste ~en effiCfltCsystem WyOU can money Roba save time K Control Horns Ball LIn Leader small Airfoil Technology Spinners New Master Airscrew series spinners four sizes Featuring aluminum backplate true running cones made red black engineering grade nylon strength resist starter burn spinners have excellent balance custom fit Available black red sizes 2 2See Hobby Dealer 21/2for MASTER AIRSCREW propellers accessories WINDSOR PROPELLER CO 3219 Monier Circle Rancho Cordova CA 95742 .. $325 375 425 .. 475 October 1989 37 Rear view Polks Challenger 550 trans mitter back case removed Note simple layout Ni-Cd pack bottom five servo-reversing switches two rotary dual-rate adjusting pots left rt Mfg 1988PO Box 1247 St Charles Illinois 60174 Master Airscrew propellers difference 76 dB equates power ra tio 57that airplane permitted emit 57 times much sonic power permitted under old standard current AMA recommendation 88 dB tougher new FAI rule Thats power ratio 76 am surprised lack consistency between AMA FAI Because have sound meter know noise propagation 100 dB 9 ft very common flying field muf flers Ive also discovered fourcycle engines sound tolerably quiet ear measure 100 dB up range Obviously subjective evaluation noise can deceptive four-cycle en gine sounds less objectionable two cycle engine yet registers almost high big ignition engine too sounds tamer its high readings meter would suggest Additionally frequency spectrum af fects perception noise see arti cle Sound Related Flying Sites No vember 1987 MA fact deserves careful thought respect relations public doubt noise levels seeing todays muffled engines pose real threat hearing especially since time standing quite some dis tance models Thank heavens mufflers After 50 years listen ing model engines mostly unmuffled hearing quite impaired high fre quency end age might have something Finally since propeller sig nificantly increases sound output use larger slower props should help allay noise problem Noisehow produce mea sure itis becoming major issue hobby today Coping problem intelligent way demands some effort means familiarizing ourselves rele vant technical terminology educating ourselves about factors influence sound emission article written purpose mind Radio Technique/Myers Continued page 37 ceiver batteries will result presence DC-DC converter receiver batteries making contact low-voltage alarm LVA system also cluded receivers PCM computer battery voltage drops below 28 volts throttle servoand throttle servogoes preset position stays typographic error receiver continues func tion down 28 volts advertised thats LVA cuts may fine get ting everything possible out alkaline batteries its dangerously low Ni-Cds think Ive got Polks convinced move trip point up around 47 volts will enough charge left Ni-Cds land safely subject batteries Chal lenger 550 manual says Transmitter 96-108 VDC 8 9 Nicad tin batteries Mine came usual Polks nine-pencell Ni-Cd pack transmitter four-pencell Ni-Cd pack receiver Transmitter operating cur rent measured 120 mA predicts about four hours operating timebetter PCM transmitters Output power looks like about 550 milliwatts Receiver drain idle five servos measured 60 mA battery charge should last about four hours ordinary service Frequency agility plug-in module transmitter inexpensive receivers make easy field changes frequency within 72 MHz band make swap field should check ground range adequate fly time no modules Ham CB bands well does work Bob Aberle t did field test system performed very well type testing last discussed May 1988 column discussed length January 1986 column results testing follows M200 adjacent channels 20 kHz Gold FM old AM ilver AM 0 kHz Gold FM Gold AM ilver AM djacent-channel performance excellent 1989 environment Polks still working develop 'bulletproof receiver 1991 turns out job some folks expectedContinued page 148 October 1989 147 ALTIMETER PERKIN AVIONICS PC-i micro sized altimeter has designed specifically RIO soaring enthusiast high tech instrument comes ready go minimal installa tion required MEASURES ALTITUDE IN 10 FT INCREMENTS AND STORES IN MEMORY HIGHEST AGL ON EACH FLIGHT WEIGHS LESS THAN 4 OZ LED DISPLAY CAN BE MOUNTED SEPARATELY FOR EASY ACCESS AUTOMATICALLY ADJUST FOR TEMPERATURE VARI ANCE AND STARTING POINT ABOVE SEA LEVEL NO BATTERY DRAIN ON FLIGHT PACK NI-CAD Introductory price $11500 no shipping charge also PERKIN AVIONICS soon released MISSILE LOCK airborne electronic weap system information either exciting new products send $300 sase C S PO Box 396 Ellenwood GA 30049 Call404 366-1591 THE WORLDS FINEST SMALL ENGINES M200 Flight Line Simulation 20 kHz Gold FM/Gold FM 36 Gold FM/Gold AM 36 Silver FM/ Silver AM 36 40kHz Gold FM/Gold FM 36 Gold FM Gold AM 36 Silver FM/Silver AM 36 Something good going FLS test dont know what PCM computer ap parently treats intermodulations same way way better older sets servos rated six volts four AA al kaline batteries specifications However Charles Hampton has flying HS-402 servos over year five-cell Ni-Cd pack has no troubles Hitec needs rewrite its specifi cation include 70 volts five-cell Ni-Cd pack slim S plug compatible last years Molex will used 1989 aircraft ra dios new HS-422 servo becomes standard aircraft radio servo year HS-422 projects / less below mounting plane does previous HS-402 uses custom chip like Futaba does features new motor very smooth gear train faster able work down 28 volts output shaft supported twopiece metal bearings above below final gear should no trouble wearing oval holes case happened old days plastic-to-plastic bear ings HS-XXX servos pulse-width controlled have 155-millisecond neutral practi cally servo should work radio worth knowing servos work great five-cell Ni-Cd packs give torque faster operation found little surgery plastic plugs would let use Airtronics servo Challenger 550 receiver Depending sequence - al wires plugs other manufacturers servos may also work bench counted 108 steps servo responding 300 full swing aileron stick High Rate count reduced dual-rate lever 31 steps full range its trim lever count affected dual-rate switch function PCM computer quite fast seems use eight-bit words Since servo throw 300 equates step per /20 motion Reso lution centering good Recentering after working stick oppo site sides usually exact never worse /2 0 out place corresponds t PCM code Using variable speed motor-driven device work landing gear switch back forth watching long pointer move over large pro tractor detect servo could no longer keep up input movement determined system can follow 120 cycles per minute four-cell Ni-Cd receiver pack servo alone can keep up 140 cycles per minute 600 travel better servos pwn have say system fast enough anybody charger supplied Challenger 550 puts Out 108 volts 50 mA 57 volts 50 mA marked will have supply own charger want use five-cell re ceiver pack frequency flag supplied Polks also nice Fun FIy/Kruse Continued page 47 David Narance Marion OH Henry M Neweome Bowling Green OH Fran cis H Nixon Lake Charles LA Frank V Noll Dayton OH Roger G Ormson Barron WI Santiago Panzardi Fairborn OH Antony Peters New York NY Phillip W Pratter Jamestown OH Timothy P Procuniar Beaverereek OH Joseph L Re inhard Columbus OH Donald H Ross Cresskill NJ James M Ruley Spring field OH Dennis F Sadowski Dayton OH Eugene P Schepers Upper Mont clair NJ Pete Schmidt Grand Rapids MI Albert Seidowski Cleveland OH Robert J Smyth Cincinnati OH Michael R Still Kokomo IN Glenn Stucker West Chester OH Darren B Suter Paden City WV Clifford J Tacie Mt Clemens MI Nur I Taib Bloomington IN Maurice C Tay lor Ohio City OH David R Thacker Hu Heights OH Bruce Anthony Tharpe Montezuma IA Jim Tibbitts Holland MI Gary E Underhill MD Evansville IN Thomas B Vandegrift East Berne NY Charles C Vermillion Marion IN Kirk R Voeckel Tarentum PA Gary R Wild Greenwood IN Lawrence M Wil son North Vernon IN Harold W Wint ers New Providence NJ Earl F Witt Chambersburg PA Raymond J Woodall New Kensington PA Robert S Wroblew ski Livonia MI 148 Model Aviation 7U rn-A, 6F700705/22 RF90O 3/ 6 08 Fults Tooling P0 Box 95 champaign IL PERKIN VI0N /