I SAFElY COMES FIRST have four items consideration month Model aircraft vs manned aircraft has right way CO-2 motor alert Some fuel system components will tolerate gaso line RC fail-safe systems John Preston BIRDMAN COLLIDES WITH TOY AIR PLANE Such headline could well have appeared newspapers across country result incident recently heard about birdman story hang glider pilot hit head RC sailplane slope West Coast Fortunately hang glider pilot wearing helmet other bent frames glasses shock will long remember sailplane did no lasting damage discussed incident friend used live West Coast friend surprised since visit well-known slope overlooking Pacific Ocean per sonally observed RC slope soarers hang gliders launching within 100 yards other reminded DOT/FAA brochure Model Aircraft Operating Standards published back 1972 brochure states Exercise vigilance full-scale aircraft create collision hazard also states operate closer three miles boundary airport unless permitted Also see FAA advertisement page 101 August issue MA would first admit hang glider launch site can hardly called airport However eyes people fly hang gliders full-scale aircraft despite freedom FAA regulation Simultaneous operation RC sailplanes hang gliders essentially same site appears hazard ous pursuit part both groups fliers Perhaps lived West Coast instead flatlands East might view situation differently Any West Coast slope soarers care comment would particu larly interested hearing RC sailplane fliers witnessed collision planned talk about control line safety month However couple letters mention ing possible hazards associated products market have caused us rearrange schedule First Free Flighters letter Claude Short Shalimar Florida brings note caution concerning operation Shark CO-2 motor hot weather have heard others concerning problem appears CO-2 capsule being loaded Shark charger two threads head charger engaged capsule punctured possible head charger blown off sudden release gas Mr Short attributes phenomenon possible softening plastic components under conditions high heat coupled increase gas pressure also result elevated temperature According article CO-2 motors appeared November 1979 issue British magazine Aeromodeller Liquid CO-2 stored pressure 800 psi 200C 680F may rise twice pressure hot summers day Remember British hot summers day just pleasantly warm compared summer parts US made several phone calls unable determine Shark CO-2 motor currently being distributed US manufactured England did find problem present either Brown Telco motors own Shark CO-2 motor live part country summer brings very hot weather perhaps following tips Mr Short will prevent mishap could lead injury a Keep cartridge C 0-2 capsule charging gun cool place like ice chest use b Wear heavy gloves preferably leather main ly protect against CO-2 burns c Wear safety glasses goggles d Point charger head away other people objects yourself screwing charger body Does use gasoline plastic fuel tanks represent potential hazard story received some will dissolve filled gasoline Again made several phone calls also carried out experiment own result gasoline does dissolve either Sullivan Kraft tanks rubber stopper Sullivan tank got bit squishy didnt leak conversation Eric Startup Sullivan Products told changing material both stopper clunk line Buna-N rubber superior Neoprene resisting attack gas assume people know neither silicone nor surgical rubber tubing can used convey gasoline Neoprene works OK fuel lines outside tank told used within tank immersed gas will degrade over period time Buna-N material used rubber components automobiles come contact gasoline Note Buna-S materials used seals diaphragms etc brake system auto mobiles except Citroens resistant gasoline have ever put power steering fluid brake master cylinder reservoir car will have sadly found out Before leaving subject fuel tanks note Sullivan Products now stating tanks should used diesel fuel present time hesitate recommend what use diesel fuel tank other metal Perhaps readers can advise us have personal interest since large delta model nears completion work shop slated used compare performance 60 Davis diesel head variety other glow fuel motors metal tank neoprene fuel lines slated used final topic discussion month concerns information safety device men tioned previous column will retard throttle servo either battery pack voltage falls critical level transmitter signal lost noticed Showgram newsletter AMA Show Teams Spirit America Show Team plans use such device models year letter Jim Hubbard VP produced some literature gadget known Battery Guard manufac turer R F Enterprises 106 N Main Street Arlington Ohio 45814 can reached 1-419-365-5360 Jim tells us current price $4995 Well worth Another device similar purpose Battery Guard available England manufactured firm called Chromatronics known PPl M-4CH RC fail-safe device According advertisement will work 3-wire positive pulse servo has individual pre-set controls four servos variable fault detection thresholds As understand addition responding low battery loss transmitter signal device will also trigger outside interference detected occurs four servos lesser number controlled PPl M will assume pre-set positionscould neutral elevator rudder aileron low throttle acknowledge would much help saving pattern model process performing say three axial rolls might worthwhile gadget sport flier living area heavy interference price 1495 approx $35 address should interested Chromatronics Creative Electronic Design Coachworks House Riverway Harlow Essex CM2O 2DP England John Preston 7012 Elvira Court Falls Church VA 22042 September 1980 69 SAFE FLYING ISNO ACCIDENT