Noise levels!

Could y'all please post any noise level readings you have?

There is a post over on the BMFA website and the poster wants some info to help with a new site (flying that is - not web!)

What are the factors - engine, silencer (or not), distance ....

Tony

Our club has monitored noise levels for a decade or so, when a mandatory muffler rule was adopted. It began as prevention and now has saved the flying site. We strictly enforce AMA's recommended 90db at 9 feet standard. A 91 or 92 reading will ground the model before flight. The club president and the field marshall have meters and we do keep a 100% record of what is flown, engine, muffler and prop. We have many pages of records. Both our meters are from Radio Shack, moderately priced. They have been checked against state owned equipment and are acceptably accurate.

Most stunt engines will read in the mid to upper 80db's with regular mufflers. Tongue mufflers are more problematical, especially on Fox's. Note, tho, that changes in prop, fuel etc can easily bring acceptable readings up above 90db. Higher performance engines take more careful monitoring.

Hope this helps.

the rpm and diameter of the prop are key factors. When the tips get going near supersonic the noise and irritation factor go way up. The think the rule of thumb is 130- if the prop diameter in inches times the rpm in thousands is over 130 you will start to see problems.

I saw this just the other day. I switched to an APC 11/3 in an effort to get a little more horsepower out of the engine to make it pull better. It probably hit around 12K in the air, and you could hear a noticeably louder, more shrill sound even when it was fourcycling. An 11/4 Zinger runs about 10.5 and sounds just fine, even with a tongue muffler.

A little off the subject, but if a city wants to ban model airplanes, here's how they do it.
They can create a noise limit that is so low that you can't even whisper. Then they selectively enforce the "code" per their whim.
Or they can just say "we don't want to hear the noise" and if any one does, you're in violation. No numbers given.
I recently beat the rap in Long Beach, CA by asking to see the "no model airplanes allowed" clause in the city ordinances. There is no such ordinance. But there is a noise ordinance which is down in the 60 dBA , 55 dBA range. Fortunately, the park ranger wasn't aware of that and besides, we were underneath the takeoff path at LGB airport. We were using chamber mufflers and no more than 8300 rpm. So we were able to keep flying.

Hi Tony,

I am trying to post the measurements we did at our club.

Hope you can use them for you benefit. You can introduce them back in excel for better analysis. I can send you the excel sheet via email as well.

Regards,
Paul

Noise measurements Mach 2003

Date RC/CL Model Fuel/ electro Motor 2T/4T prop muffler extra muffling RPM Noiselevel dB
Right Left Average

16-3-03 CL Frak-Frik fuel OS 15 FP 2T APC 8-4 standard geen 12300 75 75 75
16-3-03 RC CE-WE fuel OS 40 LA 2T APC standard silicone nademper 73 75 74
16-3-03 RC CAP fuel OS 91 FS 4T APC 14-7 eigenbouw 8000 80 79 79.5
16-3-03 RC Helicopter fuel OS 61 2T Tuned pipe silicone nademper 78 73 75.5
16-3-03 RC Mustang fuel OS AL 15 2T APC 8-6 Standaard silicone nademper 11000 67 71 69
16-3-03 RC Prima fuel HB 4,5 cc 2T APC 9-6 OS tunedpipe 11000 77 75 76
16-3-03 CL Stunt Wing fuel OS 40 FP 2T Kavan 10-6 Standard 11000 77 79 78
16-3-03 RC F18 Hornet Elektro Contronic 480 Brushless 2T Wemotec 32000 72 72 72
16-3-03 RC Prima fuel HB 4,5 cc 2T APC 9-6 OS tunedpipe 11000 77 75 76
16-3-03 RC Champion fuel Magnum 2T APC 11-8 standard 9500 76 76 76
16-3-03 RC Helicopter fuel OS 7,5 cc 2T Hatori Silicone nademper 76 78 77
16-3-03 RC Sensation fuel OS 47 FX 2T APC 11-8 Standard 10000 83 81 82
16-3-03 RC Corsair fuel Saito 11cc 4T APC 13-6 Standard 7500 75 76 75.5
16-3-03 RC Hots 40 fuel OS 40LA 2T standard 9000 74 76 75
16-3-03 RC Champion 90 fuel ST 15 cc 2T APC 14-10 Krumsheid 1099 nademper 8300 81 80 80.5
16-3-03 RC Fun fuel Enya 7,5 cc 2T APC 11-7 ? 10500 78 81 79.5
16-3-03 RC Chipmunk fuel OS 70 FS surpass 4T APC 11-6 standard 10000 81 80 80.5
16-3-03 CL Freebird fuel OS 40 FP 2T APC 11-5 Standard 7300 74 78 76
16-3-03 RC Helby Fly fuel OS 15 FP 2T 8-4 standard 14200 74 78 76
16-3-03 CL Magnum fuel ST 51 CL 2T APC 12-6 Standard 7000 72 76 74
16-3-03 RC ASH 25 Elektro Contronic 502 2T cam folding 16-10 5000 68 68 68
16-3-03 CL Wildcat fuel OS 15 FP 2T APC 8-4 Standard 1kamer 12700 73 75 74
16-3-03 RC Eigenbouw Elektro Speed 600 2T 10-12 4300 63 63 63
16-3-03 RC Apache fuel OS 46 LA 2T APC 11-7 Standard 9700 76 78 77
16-3-03 CL Wildcat fuel Thunder Tigre 42 2T APC 10-6 OS demper 12000 83 81 82
16-3-03 RC Piper Cub fuel Saito 80 FS 4T Menz 15-6 Standard 7200 76 76 76
16-3-03 CL Buster (clubvlieger) fuel OS 10 FP 2T Tornado 7-6 Standard 11500 70 71 70.5
16-3-03 RC Zero fuel Saito 65 FS 4T APC 13-6 Standard 9500 77 79 78
16-3-03 CL Mystere fuel OS 40 FP 2T APC 11-6 Standard 7200 74 79 76.5
16-3-03 RC Tayeiro fuel OS 160 FX fi 2T APC 15,5-12 4 blad Hatori 900 7200 79 81 80
16-3-03 RC Piper 63 fuel Zenoah 62 cc 2T 20-10 Eigenbouw 6300 84 80 82
16-3-03 RC AT 6 fuel Saito 91 FS 4T APC 16-6 Standard 7200 81 80 80.5
16-3-03 RC Tayeiro fuel OS 160 FX fi 2T APC 16-16 Krumsheid 6800 80 80 80
16-3-03 CL Kwispel fuel OS 10 FP 2T Tornado 7-6 standard 9700 68 71 69.5
16-3-03 CL Dragqueen fuel Stalker 61 RE 2T Brian Eather 12-6 UC standard 9200 81 80 80.5
16-3-03 RC Diamant fuel OS 6,5 cc 2T APC 12,12-3,75 standard 10300 75 79 77
16-3-03 CL odmeyn fuel OS 10 FP 2T TF 7-6 standard 11300 72 76 74
16-3-03 RC Diablotim Elektro AXI 2820-12 2T 12,5-7,5 60 66 63
16-3-03 RC Sukoi 26 fuel Saito 65 FS 4T APC 13-7 standard 7500 76 76 76
16-3-03 CL Wildcat fuel OS 15 FP 2T Kavan 8-4 Standard 13500 75 77 76
16-3-03 RC Skycat Elektro AXI 2820-12 2T Aeronaut 12-6,5 7300 64 68 66
16-3-03 RC Sportster fuel OS 52 FS 4T 11-7 standard 9500 78 78 78
16-3-03 RC Elektro zwever Elektro Speed 600 5300 66 67 66.5
16-3-03 CL Wildcat fuel OS 15 FP 2T APC 8-4 standard 14000 72 73 72.5
16-3-03 CL COX crusader fuel BABE BEE 049 2T COX 5,5-4 coxdemper 14300 79 77 78
16-3-03 RC Elektro Elektro Lenier 10 cellen 2T 14-9,5 4600 75 75 75
16-3-03 RC Kadett Lt40 fuel Saito 50 FS 4T APC 13-6 eigenbouw 7700 73 78 75.5
16-3-03 RC Fournier Elektro Ultra 900 12-6 7500 71 70 70.5
16-3-03 CL Bearcat fuel OS 40 FP 2T Kavan 10-6 standard 10200 76 78 77
16-3-03 CL Blue Pants fuel OS 20 FP 2T Robbe 806 standard 10400 76 77 76.5
16-3-03 CL Banshee fuel OS 40 FP 2T APC 11-4 standard 9700 73 74 73.5
16-3-03 RC eigenbouw fuel Saito 90 FS 4T 13-9 APC Merker 8600 81 80 80.5
22-3-03 RC Four Star 40 fuel Saito 56 FS 4T 10-6 graupner standard 9200 75 81 78
22-3-03 RC Superstar 40 fuel OS 46 LA 2T APC 11-6 standard Silicone pijpje 9400 74 78 76
22-3-03 RC Accider fuel Magnum 8,5 cc 2T 11-7 standard 10000 80 78 79
22-3-03 RC Pilatus Porter fuel SM 30cc 2T APC 20-8 Krumscheid 6600 81.5 82 81.75
22-3-03 RC Back in town fuel OS 40 2T 10-6 standard 11000 78 78 78
22-3-03 CL X1 fuel OS 25 LA 2T 9-5 dubbelkamer 10400 73 73 73
22-3-03 RC Piper Grasshopper electro Speed gear 600 13-10 klap 4200 71 71 71
22-3-03 RC Pilatus Porter fuel Sm 30cc 2T profi 18-10 Krumscheid 6800 80 81 80.5
22-3-03 RC Stick Big fuel Webra 61 2T APC 12-10 standard Silicone nademper 11100 81 81 81
22-3-03 RC Telemaster fuel 7,5 cc Aps 2T 11-7 2 kamer 10400 76 76 76
22-3-03 RC Twin jet electro 480L 4-11 14700 72 72 72
22-3-03 RC Eigenbouw E1 fuel Super Tigre 90 2T APC 14-8 standard 8200 77 78 77.5
22-3-03 RC Discovery fuel TS 46 2T Graupner 11-6 standard 10300 81 77 79
22-3-03 RC Thermik Star electro Speed gear 600 13-8 Aeronaut 4300 67 67 67
22-3-03 RC Tojero fuel OS FX 160 2T APC 17-12 Hatori 900 7000 79 82 80.5
22-3-03 CL Magnum SIG fuel OS 46 SF 2T Master 11-6 standard 9500 72 75 73.5
22-3-03 RC Tojero fuel OS FX 160 2T APC16-16 standard 6600 78 80 79
22-3-03 RC Seagull 40 fuel OS 46 LA 2T APC standard BMI nademper 9900 75 78 76.5
22-3-03 RC PT40 fuel OS 40 LA 2T APC 11-5 standard verlengstuk 9400 73 75 74
22-3-03 CL Eigen ontwerp fuel Super Tigre 46 Bullsring 2T 11-6 standard 9100 79 75 77
22-3-03 RC F18 jet electro 400 B&L 73 78 75.5
22-3-03 RC Telemaster fuel MDS 2T 11-8 standard Verlengstuk 7300 75 74 74.5
22-3-03 RC Piper fuel MDs 3,5 2T standard 11300 81 80 80.5
22-3-03 RC Charter fuel OS 2T 10-7 standard Silicone demper 10800 80 79 79.5
22-3-03 RC Colibri fuel OS 15 FP 2T Graupner 8-4 standard 10100 74 70 72
21-4-03 RC Heli Xcell fuel Zenoah 22,5 cc 2T Speciaal 80 80 80
21-4-03 RC Dazzler 40 fuel OS 46 LA 2T Graupner 10,5-6 Standard 9400 78 77 77.5
11-5-03 CL SV11 fuel Stalker 51 RE 2T Zinger 12-6 Standard 7700 78 78 78
11-5-03 CL Eigen ontwerp fuel Webra 40 blackhead 2T Graupner 10,5-6 OS demper Silicone pijpje 8100 79 78 78.5
11-5-03 CL Kwizzpel electro Speed 400/ red APC 8-4 7100 60 61 60.5
31-5-03 RC Panter fuel Thunder Tigre 10cc 2T APC 11-8 Standaard 11200 81 82 81.5
15-6-03 RC Big Lift fuel Tartan 24cc 2T APC 16-8 Eigenbouw 3k 7600 77 76 76.5
19-7-03 RC Piper fuel Zenoah 38 cc 2T Zig 20-8 Origineel 6900 87 83 85
13-9-03 RC Discovery fuel OS 40 FS 4T 11-6 Origineel 8700 70 75 72.5
13-9-03 RC A Rising Star fuel Irvine 6,5 cc 2T 11-7 Standard 9200 79 76 77.5
20-9-03 RC Porter fuel 30cc 2T APC 20-10 Krumsheid 4 kamer Inlaatfilter 6850 82 82 82
20-9-03 RC Spats fuel Saito 5,5cc 4T 11-6 Standard 7200 65 65 65
20-9-03 RC Lazy Ace fuel Webra 61 2T 13-6 Standard Silicone demper 10600 81 78 79.5
20-9-03 RC Trainier Graupner fuel OS 46 la 2T 11-6 Standard 9600 70 76 73
11-10-03 RC Fun MODO fuel Irvine 53 2T APC Standard 3k 9800 78 80 79
11-10-03 RC Four Star 40 fuel OS fp25 2T 9-6 Standard 10200 78 78 78
11-10-03 RC Porter fuel Mark 35 2T 20/10 Merker 6600 83 81 82
19-10-03 CL Nobler fuel FOX 35 2T 10-6 hout OS FP 1 k 8500 77 78 77.5

GREAT STUFF!!

I have to add that measurements were taken at 7 meter distance, at a heigth of 1 meter over grass(model and measurement equipement (Bruel & Kjaer). Model was held with the fuse side towards the microphone.2 measurements were taken.left and right side. The average is calculated lineair, but is should be logaritmic. This was done for simplicity.