How LOUD is LOUD ?

Question

One of the BluesRocks Sections flying sites is the beautiful Masterson Station Park in Lexington Ky.....

We have received permission from the Parks and Recreation board to launch our models there, whereas No RC airplanes are allowed at all....(seems a large RC model airplane went through an adjoining subdivisions house plate glass window..)

Like a lot of parks these days, MSP is multi-functional.....for example it has the requisite soccer fields out the wahzoo....it has a outdoor hockey rink, a dog park, a small open air stadium where they have junk/dirt car races and such, and at one end of the park they have horse riding stables .....

The purpose of this post is to ask: Has anybody every done any sound level/decibel studies on how loud specific model rocket and especially HPR motors are?

I know that the AMA has rules about the noise level that RC planes can do, and I was wondering if any research has been done in this area for MR/HPR.....

The reaon I ask this question is the horse riding stables.... I don't know if you have ever been around horses, but they can be spooked quite easily by sudden loud noises.... for example, my retard nephew this past 4th, while out at a horse farm where my daughter lives, set off some firecrackers and across the road (50 ft?) was a barn with horses and he scared them....I smacked him upside side his head, and said, now that was stupid.... I guess thats why hes a retard huh? Anyway I digress...

At MSP we actualy have 2 launch areas....the smaller area maybe 1/4 mile sq if for model rocketry....it is the furthest away by at least 1/2 mile or more from the horse riding stables...

the larger launch area is right next to the horse riding stables and is appox 1/4 x 1/2 mile.....

It is more suitable for small HPR up to perhaps HI...

I'm just asking if any research by either manufactueres or the national orgs have been done regarding the potential noise pollution of certain rocket motors?

TIA

shockie B)

Joel Corwith · Accepted Answer

You want I should take my Db meter on Saturday?  ABC type of stuff thismonth.Joel. phx

Ken Sparks · Answer

Yes.

shockwaveriderz · Answer

Is there a specific characteristic of an engine that might determine howloud it might be? for example a high initial thrust spike? propellant type?TIAshockie B)

Jerry Irvine · Answer

Pressure.Massflow.Pardon the tech post.

Jerry Irvine · Answer

ROFL

almax · Answer

Hum, a new propellent type for AMW?Quiet Cat

Jerry Irvine · Answer

USR has a "loud" propellant. It is not marketed.

Alan Jones · Answer

Exhaust velociy and mass flow.  Most of the noise comes from theviscous shearing between the supersonic exhaust stream and therelatively still atmosphere.Alan

David Weinshenker · Answer

In practice, this means that the noise level is pretty much proportional to the thrust level: an I200 is as loud as an H200, for twice as long... and a 200 newton peroxide motor is that loud until the tank runs out.

-dave w

Kenneth C. McGoffin · Answer

Noise level will increase as any of the following factors increase:1) Thrust2) Combustion instability3) Exhaust velocity+McG+

shockwaveriderz · Answer

thanks guys for helping me to understand the underlying causes for the noise....now a nother question...... Does the propellant formulation/type play a role in determining exhaust velocity and mass flow characteristics of an engine? I assume that pressure also plays a role here? For example is white lightening or blue thunder louder than say a redline ?

Could one create a "soundprint" of a specific motor?

shockie B)

How LOUD is LOUD ?

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