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Pilottonny

Well Known Member
Hello,

Since there are still no diesel engines readily available, (Wilksch: no news!, Centurion: only to OEM?s,), I decided on the ECI-Titan IOX320 with double electronic ignition and run it on Mogas. (164 bhp) Due to availability in Europe, the fact that it is supposed to be silent and its low weight, I am opting for the MTV-11C/183-59, 2-bladed CS Propeller.

Because that engine is going to make to much noise for European regulations I am trying to find a supplier for some silencers.

Vettermann " thinks" his silencers will be good for about 6 dB(A), definitely not enough! Now I am talking to a silencer manufacturer in Germany who thinks he can get it down to the very stringent German regulations of "Erh?hter Schallschutz" and is willing to guaranty that, but to calculate the silencing, he needs a lot of information. Through the "search feature" I could find most, but I am still looking for the following :

- Max rate of climb, at what airspeed?
- Take off over 50 feet obstacle.

Anybody out there with a prop/engine combination that comes close to, or is what I am planning, that can get me the above info? I would really appreciate it.

Regards,

PilotTonny.
 
Pilottonny said:
Hello,

Vettermann " thinks" his silencers will be good for about 6 dB(A), definitely not enough! Now I am talking to a silencer manufacturer in Germany who thinks he can get it down to the very stringent German regulations of "Erh?hter Schallschutz" and is willing to guaranty that, but to calculate the silencing, he needs a lot of information. Through the "search feature" I could find most, but I am still looking for the following :

Regards,

PilotTonny.
Click to expand...
Tonny,

I cannot comment on the ROC or distance to climb 50' but I can comment on the silencers or mufflers as we call them here.

Tony Bengals designed a simple muffler to meet the European noise requirements. He took some screen material, wrapped it around a pipe w/ holes along its length and then put a solid aluminum piece over the entire thing. It was long, maybe a meter or more in length and needed to be suspended under the fuselage.

I could not find a reference to it on the net but maybe someone on the list can post a picture of it.
 
Liese in Germany is making small efficient silencers. I read about another german installing "Swiss mufflers" on his BMW Motorcycle conversion. It didn't work. He also wrote about third party tuned exhausts for the BMW motorcycle which supposedly should increase power. A German Motorcycle magazine tested them, and all of them decreased the power compared to the original exhaust supplied by BMW ! Still, people continue purchasing those third party "tuned exhaust" :)
 
Liese is asking the questions!

It is actually Liese who I am now talking to. The silencers he is offering are very expensive, compared to the Vetterman mufflers, so before I go that way, I want to be sure it is going to work.

I know about the swiss muffler, but after having seen some pictures of how ugly the plane looks with a 6 ft pipe under its belly, I abborted that idea. Not only will it cost speed because of some power loss, but also because of the extra drag.

All I need to know is max rate of climb and take off over 50 ft obstacle! Come on, so many flying RV9A's, there must be some one who has got that info?

Thanks in advance.

PilotTonny.
 
If you are willing to try build silencer by yourself, you might look at this site http://www.mh-aerotools.de/airfoils/software.htm and Acoustic Analysis of Silencers and Tuned Pipe Design. Just note that the program is designed for 2-stroke engines and therefore you should divide RPM by two.

There are also lot of ideas in the patent databases you might take a look if building your own sounds like an possible idea.
 
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