Flying Field Layout to Meet Noise Criteria

F H have can gener other operate scribed THE NOISE ISSUE attracting increas ing amount concern among modelers days major reason concerned noise neighbors object object enough lose flying fields course no neighbors near fields will no problem question near too near has great deal study done over years subject environ mental noise issue health hazard consequence exposure high levels personal risk model ers hearing seriously reduced probable result 50 years listening airplane engines will cost us flying fields other issue pub lic reaction noise exactly problem no question matter noyance due noise subjective Modelers will tolerate great deal model airplane noise person trying take nap Sunday afternoon have some studies made public reaction noise have reference International Organization Standard ization ISO2 will use basis discussion referenced standard follows pro cedure set curves relate noise intensity frequency provide Noise Rating N curves shown Fig 1 correction applied N number considers number 34 Model Aviation factors spectrum repetition time day etc See Table 1 Finally table shows probable public reaction noise See Table 2 have used Table 2 estimate much noise can impose neighbors out trouble Table 1 curves Fig 1 have determined great distance must provided between airplanes neighbor meet noise ceiling Table 2 determined since would desire no reaction must present N ess Let us assume 35 Table 11 get correction five based upon pure tone continuous exposure o previous conditioning daytime summer rural neighbor hood must subtracted Public Reaction noise rating found Table 2 give desired noise rating num ber N se Fig 1 must make some sumptions regarding frequency noise generated airplanes 6000 rpm fundamental frequency will 100 Hz 12000 rpm will 200 Hz 18000 rpm will 300 Hz chose 250 Hz 15000 rpm un reasonable figure engine unloaded flight Fig 1 see N 50 Hz yielding 40dB means must present no 40dB neighbors property line What kind field layout dictated requirement Assume current rule book figure FM RC Aerobatics 100dB 1 meter Thats equivalent 90dB 10 ft desire 40dB neighbors location Thats differ ence 50dB power ratio 100000 inverse square law applies thus find square root 100000 316 means must distance 10 x 316 3160 ft between airplane neighbor ensure ac ceptable level noise follows AMA recommendations field layout given page 131 rule book calls 2000 x 500-ft fly-over zone must add 3160-ft buffer direc tions would require area 6820 x 8320 sq ft about 1290 acres Fig 2 illustrates required field layout Lets assume get noise down 80dB 10 ft gives following 80 40dB 40dB ratio 10000 square root 10000 100 Finally 100 x 10 ft Thus airplane can approach no closer 1000 ft neighbor Thats lot better still calls field 2500 4000 ft 227 acres Another 10dB reduction 70dB would call 30dB ratio 1000 square root 316 thus could approach within 316 ft neighbor Continued page 140 Corrected Noise RatingEstimated Public Reaction Number Below 40No observed reaction 40-50Sporadic complaints 45-55Widespread complaints 50-60Threats community action Above 65Vigorous community action Source 1802 625 November 1987 35 Table 2 Public Reaction Noise Residential Districts SO NO gotta borrow glow borrow GLOW PLUGS Are Available Local Hobby Shop Parts People PO Box 26247 Orleans LA 70186 0-535-2568 think may able get 80dB 10 ft Yet doubt very much well ever get 70dB might point show just pro found effect noise generated engines has real estate require mentsand significant impact improvements can make think its important problem deserves atten tion of us AMA References Ernest J McCormick Human Factors Engineering Third Edition McGraw-Hill Book Co New York 1970 pp 525-528 2Rating noise respect hearing con servation speech communication noyance ISO Technical Committee 43 Acoustics Secretariat-189 August 1961 SAFE FLYING IS NO ACCIDENT Nats General/Worth Continued page 39 uations RC events Control Line door Scale RC Pattern Pylon Scale acres concrete Lincoln Airport RC Helicopters nice park fly RC Soaring sod farm Con trol Line huge concrete apron airport well large grass Combat area close Indoor site though high big fine batch new records established comparatively large entry kept site busyit generally happy Indoor Nats good turnout helped sure Indoor will retained future Nats schedules Prior Lincoln event feared repeat last years low entry might see Indoor deleted Nats scene due high cost site ren tals No such threat expected 1988 what looked developing crisis has averted Lincoln Airport what first appeared negative factor turned very positive old military fire department building used Nats headquarters 1979 1982 available having sold renovated commercial use AMA therefore literally build headquarters area airport combination rented office trailers tents served purpose very well Three large trailers arranged U shape center U being occupied huge red-and-white circus-type tent tent became center focus activities seeming some what like big hangar Navy Nats days tent center Nats informa tion registration hobby shop trophy dis tribution PR Nats News printing tabulation Meetings held under tent cookout Scale team selec tion finalists informal gatherings tent gave shelter during rainstorm re lief hot sun latter Nats days T-shirts Nats souvenirs sold well photos contestants models Big boards under tent showed event locations schedule scores miscel laneous Nats modeling news Continued page 142 maaniiI Jct inc Only certified checks money ordern accepted Minimam order $1000 three packages 4 Pomerpolen $300 per package $100 shipping handlingt Ct renidents add 75% sales tan Prices sablect change mithont notice DEALER INOIflRIES INVITED farther information dealer prices need SASh hasinesa Card SERMOS RIC SNAP CONNECTORS Ca1 Coons StalKa Box 16787 Stamford CT tl69 203322-6294 140 Model Aviation Sound & Sites/Abbott Continued page 35