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ao.frog

Well Known Member
Hi.

To get the final airworthiness certificate for my -7 here in Norway, I need to do a "noise measurement test".

This will take a full day, require measure-equipment and people on the ground and alot of flying, and in my opunioun: a waste of time, effort and fuel... (much more fun to use the fuel for acro!)

BUT: there's one way to avoid it:
If I can find a similar engine and prop combo AND they have done a noise-measurement test, then I can use their data.

I don't know if this kind of testing has to be done in the US, but someone told me it has to be done in Germany? And maybe in the UK too?

Sooooo.... does anyone out there have a Superior IO/O- 360 engine (or an Extreem IO/O-360) and a M/T MTV-15-B/183-402 prop?? (or a simliar M/T prop)

I guess I even could use data from a Superior IO/O-360 and a Hartzell prop, so anyone??

I'm hoping now guys....
 
Hello Alf Olav,

Sorry, I can't help You. Actually I'm in the same situation as You. I need "noise-certificate" for my RV7A with Mattituck IO-360 and MTV12B/183-59B (3-blade). We're only 3 flying RV7 here in Sweden, none with same configuration. So I chime in, anyone done theese tests?

Regards,
Fredrik
 
I wish I could help you. I have a Superior IO360 (Vetterman crossover exhaust) and the MTV15B

I've never done noise testing but a friend on the ground the other day knew it was me when I flew over. He said is was a loud plane and sounded like a Bonanza (Continenal six cylinder).

At the time, I was pushing it at 25 squared to check a speed setting at 2500 feet.

What is the proceedure for checking noise level?
 
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Much work I think...

Hi Webb.

I don't know the excact procedure yet, but here's the basics:

You pick a day with no wind and std temp and an open place (for example a big field) and no additional noise (to pick an airport as the "field" is therefore not a good idea..)

You put people on the ground with special noise monitoring equipment. (EAA has that for loans here in Norway)

You fly over the measuring equipment in a straight line and at a certain height a number of times, each time with different MAP and RPM.

Each run which is accepted by the equipment (no background noise etc) has then to be repeated three times to verify the accuracy.

If the noise is within limits, then you'll finally get your "Environmental Certificate"
If the noise is too high, you've to do something to decrease it. (muffler etc)

The good thing is that the FAA in Norway accept other plane's Environmental Certificate" as long as the engine/prop combo are the same or basicly the same.

Therefore I'm hoping there's someone out there who can help....
 
hi olav,

same problem here in switzerland...

at least the local eaa (EAS) organizes noise measurements twice a year, so we don't have to organize all the equipment etc... by ourselves.

almost no installation gets accepted as similar, as there is almost always a difference with either exhaust, prop, engine or airframe.

free hint: do all your performance testing (and AFM limitation ;-) with an "artificial" MCP (max continous power) of 2500rpm max, as this performance data (at least in the procedure done here) will affect the measurement procedure. and these last 200rpm apparently make a huge difference in noise level vs very little performance impact.
the procedure by the way, is specified in "icao chapter 10" whatever that is, just a hint if you want some background info.

kind regards,
bernie
 
WOW Alf:eek:
I guess that sort of thing is headed this way...seems we're all trying to be one big happy international aviation family dominated by the rules and whims of ICAO...but I'm sure glad that we don't have to noise testing here...yet. It makes me remember the El Camino, Mustang and GTO of my youth...they were not stock setups either. Back to airplanes, as you know, you and I have basically identical setups (exact engine and maker, exhaust, prop and ignitions)...and I'm often told my plane is pretty loud in low altitude, full power mode...but I don't fly that way over people, only cows, coyotes, and jackrabbits...and they have not complained yet...but I think that's coming soon via lobbying from an animal rights group here.
 
Noise test

MT Propeller does not have any noise data for the MTV-15-B/183-402. They said this was a USA propeller.

MT Propeller has noise data for the MTV-12-B/183-59b propeller on a RV-6A with a Lyc. 360 engine. However, they felt that it would not be useable unless the exhaust systems were the same on both aircraft.

MT Propeller had the following suggestions.

OUV provides the ground test equipment and personnel for free to do noise testing. Once or twice a year at various locations in Europe. (Perhaps they have some of their test results available.)

MT Propeller offers to provide the noise equipment and personnel for a certified noise testing at their facility (airport near Straubing, Germany):
$750 EU for an MT Propeller.
$1,500 EU for other propeller.

Jim Ayers
 
[Hi Olaf,

I sold my 8 last week. BUT. I had an IO360 A1B6 with 200hp installed, used a MT three blade prop 175/59. Has all data from a certified noise measurement by MT personnally. Give me a hint if you would like to have it.

Best Regards

Stephan
D-EBRV
Sold to France
 
Friend of mine has all relevant noise data for the combination RV7 180hp and 3-blade MT 183/59. Same origin.

Regards

Stephan
 
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