Stealth-E Trail Riders

mouse1 · Quite quiet

Making life more stealth-e

Sigilo · Quite quiet

Stopped eating beans

-- Edited by Sigilo on Sunday 21st of February 2010 07:39:02 PM

Hammer · Quite quiet

Nothing much, just small groups and travelling on the more out of the way and less used lanes. Extra tarmac work but there are some nice lanes off the beaten track, so they dont get used by the "raiders" To much hassle for them to find them or to get to

But its nice to ride lanes with no tyre tracks or bike ruts in them

Sigilo · Quite quiet

and......
take off those dammed racing numbers!!!
everyone I waved to today waved back!!!
and had a loverly chat with a gorgeous lass on a horsey
try putting a few drips of pine oil in with the petrol... adds a pleasant forrest aroma... aaah!

riding the stealth way.. didn't badger all day!

whisp · Quiet

Ive been shouting from the rooftops trying to get riders to listen and consider the stealth message. blankstare

Other than that theres a reversed k&n air filter over the exhaust outlet of the fairly quiet CRF230 and a layer of black duct tape on the side panels. This bike is so stealthy it hasnt been heard running since it went to North Wales in November.

I can only apologise for the non standard XR4 FMF 'Q' pipe disbelief

Big disappointment.

Years ago a friend and me pondered how to 'elongate' the 'pop' that emanates from a four stroke, to turn it onto a 'foof' sound.
Total amount of sound released would be the same but closer to a continuous level of sound.

We considered that slowing down some of the exhaust gasses by fitting small diameter tubes of different lengths could have this effect.
So I rammed the really noisy CRD pipe that came with my old TTR full of different lengths of 10mm copper and the results were unimpressive. Longer lengths required ? Dont know.
An australian rider suggested trying to get the exhaust gasses to spiral the length of the header pipe by pushing some 6mm coiled wire through the pipe but I never got any follow up on that idea.

What does seem to work is enough mass in the header pipe and box.
Obviously of no interest to someone needing titanium spoke nipples but some of the older hondas had twin skin header pipes.
Not easy to blow out any dents though.
Nice long length of chrome plated scaffold tubing anyone ?
Another old honda trick was to have two outlets on the silencer, piped to cross each other just beyond the pipe ends and so scattering the exhaust pulse a bit better.

If just one of the aftermarket exhaust builders could see the potential for really quiet systems eh ?

There might be someone on this list whose son occasionally rides trail who is/was doing a degree in accoustic engineering. I suggested to him that theres a good amount of money to be made in getting things to operate more quietly but at the moment he seems drawn to the opposite end of the sound spectrum.

whisp

Hammer · Quite quiet

Environmentally speaking, hot exhaust gas wether noisy or not is a waste, a length of heat proof flexible piping to redirect the gas into the riders clothing, would be a god send in cold weather, keeping one warm whilst using the protective outer garments as extra sound insulation, and probably reducing the noise level to zero

Probalby fine if you are riding a smaller 4 stroke, however there is a problem with larger 4 stokes that you would blow your clothes off, and with 2 stokes you would end up much like a kipper well smoked!!!!!

Any other ideas as how to use this wasted resource

B2spirit · Quite quiet

Being able to pipe the exhaust through the handlebars would be good for me!

I have to admit that the airbox on my trusty 250 makes more noise than the exhaust so I'm going to try and line it with sticky-back neoprene...I'll report back shortly.

I used to put a VW Beetle tailpipe in the end of my B40 exhaust but that had a large bore peanut "silencer". As we don't need all the power to ride lanes then I reckon an add-on to the end can is favourite.

Started me thinking now when I needed to be thinking about Finance Act Maps and how to get a free lift to Kew!

whisp · Quiet

from http://home.comcast.net/~bzee1a/Edwards09/Edwards09.html -

( some nice plane pics if you are interested )

Lockheeds YO-3 'Quiet Star' aeroplane was designed for night battlefield observation during the Vietnam war. It was a very quiet plane, and can fly as low as 200 ft over the enemy without being heard.
Christian Jacobsen had this to add about this plane: "One of the programs I saw while I was at NASA was a project for developing quieter helicopter rotors (or for downtown VTOL public airports). They would mount microphones on the wings of the YO-3 and follow our helicopters around to do real-world testing of the various rotor designs. (A Blackhawk, an Apache, and a Little Bird.) Because it could fly slowly, silently, and close to the helicopters, it was the perfect platform for the audio testing aspect of the project."
"Every aspect of the plane was developed to be as quiet as possible... which was part of the reason it had that odd looking wooden propeller. Apparently it was the quietest prop ever made!"
Got the following from Kurt Olney, who was a crew chief on a YO-3A in Vietnam, and was helping out at Edwards with the plane: "The elements that made the plane ulltra quiet--some might say silent when it flies 800-1000 feet overhead--were the following 1. Slow turning prop 700 rpm (minimizes tip noise.) 2. An exhaust system that runs the length of one side of the airplane, 3. IO-360 continental engine enclosed in acoustic deadening cowling and silicone in the rocker box covers 4. 12 v-belts--reduction drive- (we use to call them rubber bands) that eleminate gear noise. 5. A streamlined plane. (plane is based on a Schweizer 2-32 glider but greatly modified.) 6. Duct tape. Before planes went on a mission, they would fly about 300 feet over the maintenance shack. If we heard whistles, rattles etc, we would bring her in put some tape on her. After a while we pretty much knew where the problems were likely to be so we taped her before she went up."

-- Edited by whisp on Tuesday 23rd of February 2010 07:05:25 PM

B2spirit · Quite quiet

I like that plane. I've already got the nearly full length exhaust so all I need is a load of silicone and a wooden prop. That'd clear overgrowth at the same time. Not sure about doing a 300ft flypast though?

I'm all gaffer taped up so am I Stealth-E?