Rocket Motor Noise

range. The

the

good

later in

get as

and take

I have done this, and the readings are quite high :-)

At the LCO console at 50' or minimum launch distance, whichever is greater, all the white lightning motors I got readings on briefly pegged the meter at 130 dB. Some motors sounded quite a bit louder than others; it wouldn't surprise me if some of them exceeded 140 dB.

The early econojets, as you surmised, are particularly loud.

Black Jack motors were much quieter.

FWIW,

--tc

We got bounced from our prior field because an N2000 amd 3-K700's startled some cows on a field almost a mile away. Just pi$$er$ and moaner$ anyhow...

Sounds like pretty sound PR...

How loud is it at the edge of the complainers yard ?

at 500 feet it should be 90db or much less at 1000 feet it should be much less then 86db, traffic level.

that complainer's yard should be at least 500 feet away, or the site's too small.

a model airplane 2 cycle engine is about 96db at 9 feet. much louder to the ear then a F20 at 50 feet.

are you turning off the PEAK on that meter ? It should be set to average out the sound to get reading that are meaningful.

Though my son and I fly rockets from time to time, we are not big time rocketeers. I do however has vast experience with model aircraft. First off, it`s very difficult to use a DB meter to measure "noise", the equipment registers sound frequency and "reads" that. Anyone that has "heard" a 2 cycle model aircraft engine knows they are loud when you are within a few feet (even with a muffler). You may get a reading of say 96 db`s on a meter at 9 feet or so, however run a 4 stroker and "listen" to the difference, usually much quieter to the ear yet still running in the high 90`s or 100`s on a decibel meter. Your milage may vary, but you get my point. You can use a decibel meter as a guide, however you must still "listen" with your ears to determine what motors will sound louder or more offending then others. rick markel

My Model Aircraft Home Page

Noise levels of rockets may be difficult to compare with other types of noise. The main "uniqueness" of rockets (especially high power) is the sudden and startling nature of the noise. Your neighbors may have a problem with the suprise of the noise (yes, I know, a firearm or pyrotechnic display is much louder, but let's stay focused here...) rather than any problem with the decibel level. As had been mentioned in this thread elsewhere, good PR is your best option. Notify the surrounding area of a sport launch for that day, invite the neighbors to watch a few rounds, etc.

My wife (a community nurse specializing in infants and toddlers) has noticed the effect on small children: the noise of the higher power motors can be an unpleasent experience on sensitive ears. Parents should be aware of this possibility and consider options such as hearing protection and talking the child through the event.

Fred Williams

(No celebrity impersonators were harmed in the production of this message. Your mileage and side effects may vary.)

I agree.

Also, the sound is uncommonly rich in high-frequency "white noise".

-dave w