I know that the exhaust is shunted into it when you open the valve, But I have never seen one and would like to see how they operate in a good diagram that shows how the exhaust passes thru them.
I second that request. I'm experimenting with the construction of one right now so it would be nice to see.
Hi Dennis, Sean and all
Here is a great previous thread by Dan Knoll Jr. on how to build an exhaust whistle . . .
Or here is a link to a couple of hundred whistle related patents,
many of which have detailed drawings etc. pertaining to whistles . . .
And here is a link to a Google search ‘How do whistles work’ . . .
low pressure high volume. That is because the exhaust doesn't have much push but has a lot of volume, so the whistle is fed through a big pipe at slow speed. That is how it works. You must have a valve and the best ones shut off the muffler by blocking the exhaust and diverting it to the whistle. Poor valves leak and your whistle will whine all the time.
They work just like pipe organ pipes:
"The sound of a flue pipe is produced with no moving parts, solely from the vibration of air, in the same manner as a recorder or a whistle. Wind from the "flue", or windway is driven over an open window and against a sharp lip called a Labium. By Bernoulli's principle this produces a lower pressure region just below the window . When the vacuum under the window is large enough, the airstream is pulled under the Labium lip. Then the process works in reverse, with a low pressure region forming over the Labium which pulls the airstream to the other side again. This 'fluttering' airflow creates high and low pressure waves within the pipe's air column. A high and a low pressure wave form a single "cycle" of the pipe's tone." (Wikipedia)
Not many folks have a crate of large organ flute pipes laying around to photograph--are you into organs? I help maintain our local church's 1928 Reuter Orchestral organ, and I'm working on installing a 1927 Wurlitzer "Unit Orchestra" (theatre organ) into our city's 1928 theatre.
I recently picked up an Aermore # "0" whistle.
Most whistles I have seen used on a Model T are #2. How are the whistles sized? I assume the one I have is used on a larger displacement engine.
I would like to see the size of the car that those whistles fit under!
Here is a happy man with his purchase at Chickasha 2010:
I used to work for Bedient Pipe Organ Co. in Lincoln, NE...he made period authentic tracker style instruments (usually German Baroque and French Romantic back then).
You can learn a lot out there...
Very cool! My original mentor is probably turning over in his grave about me working with a Hope-Jones instrument--he thought they were an abomination! There are two trackers in this area that I am aware of--both modern instruments; one here in Oroville at the Congregational Church, and one in nearby Chico at a Methodist Church. Can't tell you how many ranks, both are at least 2 manuals (gee, you'd think I could remember THAT detail!).
One thing about Baroque organs--you don't have to fix them, they're designed to be Baroque!
OK so much for bad organ humor, though I thought it was Swell.
Well I had a swell of low pitched laughter on that one! LOL
"STOP. Both of you." he bellowed.