On Sep 8, 10:42*pm, wrote:
On Sep 8, 7:12 pm, wrote:





On Mon, 8 Sep 2008 18:32:05 -0400, "Eisboch" wrote:

wrote in message
....

WTF? Can't they put a muffler system on them, or is it the blades that
make the most noise?

----------------------------

Trust me. *The engine is loud.

The prop is much, much, louder.

Eisboch

Down at Wootens the make the passengers and the drivers wear ear
protection. I don't know of anyone who doesn't.
I do know a couple guys down in Everglades City who have airboats.

So, why not put a shroud round the prop, it shoudl at least silence it
some?- Hide quoted text -

- Show quoted text -

The hovercraft I built had an optional build for a close fitting
shroud that actually was supposed to boost thrust a little. I made it
and installed it. As I recall it didn't help noise much if any at all.

On Sep 8, 6:58*pm, Tim wrote:
On Sep 8, 5:32*pm, "Eisboch" wrote:

wrote in message

...

WTF? Can't they put a muffler system on them, or is it the blades that
make the most noise?

----------------------------

Trust me. *The engine is loud.

The prop is much, much, louder.

Eisboch

Yes, go to an air show sometime and listen to a PiTT Special or a
Citaborea make a low altitude fast fly-by.

BWWWWWWAAAAAAAAAAAAAAAAHHHHHHHHHH!

The noise you actually are hearing is the prop beating the air. then
after they make the pass they get a lot quieter and you hear the
engine rumble.

What's cool is if somebody comes up with an old WW2 Corsair *and makes
a fly-by. Yes, you hear a tremendous noise coming fromt he prop then
when they pass you hear that marvelous "gallop:" of the Pratt 'n
Whitney radial!

My uncle worked on Corsairs as a CPO. I've got Navy ww2 service
manuals his tech school manuals, etc. Really nice to have! What is
cool about them is that again, they didn't just go to the store to buy
a part, they made a lot of parts so the manuals go into great detail.
Another interesting thing is when you are standing close to an
airplane and they are checking it out and at a certain RPM they go
through the range of prop pitches. Sounds a whole lot different
between fully pitched and feathered.

On Tue, 9 Sep 2008 07:19:30 -0700 (PDT), wrote:

and at a certain RPM they go
through the range of prop pitches.

Those props have a governor that keeps the speed constant, regardless,
within limits, of load or throttle setting. More usual to go through
the range of pitches by varying the RPM with the prop governor. That's
the way everyone I ever knew did it. An airboat doesn't need a
variable pitch prop, as it doesn't climb and dive.

Casady

On Sep 9, 2:47*pm, (Richard Casady) wrote:
On Tue, 9 Sep 2008 07:19:30 -0700 (PDT), wrote:
and at a certain RPM they go
through the range of prop pitches.

Those props have a governor that keeps the speed constant, regardless,
within limits, of load or throttle setting. More usual to go through
the range of pitches by varying the RPM with the prop governor. That's
the way everyone I ever knew did it. An airboat doesn't need a
variable pitch prop, as it doesn't climb and dive.

Casady

Richard, I fully understand an airboat doesn't need a vari-pitch prop.
It would be fun to try one to see the difference in the hole shot,
though! When testing controls, it's common to set the RPM's to a
certain setting, more akin to a fast idle, and run the pitch controls
through the range. The prop governor isn't a factor at these low RPM's.

On Tue, 9 Sep 2008 12:03:57 -0700 (PDT), wrote:

On Sep 9, 2:47*pm, (Richard Casady) wrote:
On Tue, 9 Sep 2008 07:19:30 -0700 (PDT), wrote:
and at a certain RPM they go
through the range of prop pitches.

Those props have a governor that keeps the speed constant, regardless,
within limits, of load or throttle setting. More usual to go through
the range of pitches by varying the RPM with the prop governor. That's
the way everyone I ever knew did it. An airboat doesn't need a
variable pitch prop, as it doesn't climb and dive.

Casady

Richard, I fully understand an airboat doesn't need a vari-pitch prop.
It would be fun to try one to see the difference in the hole shot,
though! When testing controls, it's common to set the RPM's to a
certain setting, more akin to a fast idle, and run the pitch controls
through the range. The prop governor isn't a factor at these low RPM's.

Sure it is. The pitch control is connected to the governor, which
moves the prop blades.

Casady

wrote:
On Sep 8, 7:12 pm, wrote:
On Mon, 8 Sep 2008 18:32:05 -0400, "Eisboch" wrote:

wrote in message
...
WTF? Can't they put a muffler system on them, or is it the blades that
make the most noise?
----------------------------
Trust me. The engine is loud.
The prop is much, much, louder.
Eisboch
Down at Wootens the make the passengers and the drivers wear ear
protection. I don't know of anyone who doesn't.
I do know a couple guys down in Everglades City who have airboats.

So, why not put a shroud round the prop, it shoudl at least silence it
some?

No ear protection offered here. The boats are load at WOT but not
deafening.

http://www.evergladesholidaypark.com/airboats.html

On Tue, 09 Sep 2008 19:26:53 -0400, DK wrote:

wrote:
On Sep 8, 7:12 pm, wrote:
On Mon, 8 Sep 2008 18:32:05 -0400, "Eisboch" wrote:

wrote in message
...
WTF? Can't they put a muffler system on them, or is it the blades that
make the most noise?
----------------------------
Trust me. The engine is loud.
The prop is much, much, louder.
Eisboch
Down at Wootens the make the passengers and the drivers wear ear
protection. I don't know of anyone who doesn't.
I do know a couple guys down in Everglades City who have airboats.

So, why not put a shroud round the prop, it shoudl at least silence it
some?

No ear protection offered here. The boats are load at WOT but not
deafening.

http://www.evergladesholidaypark.com/airboats.html

Looks like each engine goes into a dual exhaust with some big mufflers.
When I rode, we were given ear muffs. The operator was wearing them also.

wrote:
On Tue, 09 Sep 2008 19:26:53 -0400, DK
wrote:

wrote:
On Sep 8, 7:12 pm, wrote:
On Mon, 8 Sep 2008 18:32:05 -0400, "Eisboch" wrote:

wrote in message
...
WTF? Can't they put a muffler system on them, or is it the blades that
make the most noise?
----------------------------
Trust me. The engine is loud.
The prop is much, much, louder.
Eisboch
Down at Wootens the make the passengers and the drivers wear ear
protection. I don't know of anyone who doesn't.
I do know a couple guys down in Everglades City who have airboats.
So, why not put a shroud round the prop, it shoudl at least silence it
some?
No ear protection offered here. The boats are load at WOT but not
deafening.

http://www.evergladesholidaypark.com/airboats.html
\

The owner says he has never heard a complaint.



Aside from the particular sound pressure levels, how is an airboat
supposed to sound much different than a low-flying (very low flying)
single-engine prop airplane right over your house or in your front yard?
When we lived in Florida, we weren't very far from the St. Augustine
airport. The airport generated some loud noises once in a while, when
the military reservists played with their jet engine, but we rarely
heard any sounds from the general aviation craft, prop or jet, or even
the small commercial jets that landed there. Even the seaplanes were
quieter than the airboats.

On weekends, before we got some enforcement of noise pollution measures,
we had a couple of airboaters whose special delight seemed to be to get
an early Sunday morning start.

"John H" wrote in message
...
On Tue, 09 Sep 2008 19:26:53 -0400, DK wrote:

wrote:
On Sep 8, 7:12 pm, wrote:
On Mon, 8 Sep 2008 18:32:05 -0400, "Eisboch" wrote:

wrote in message
...
WTF? Can't they put a muffler system on them, or is it the blades that
make the most noise?
----------------------------
Trust me. The engine is loud.
The prop is much, much, louder.
Eisboch
Down at Wootens the make the passengers and the drivers wear ear
protection. I don't know of anyone who doesn't.
I do know a couple guys down in Everglades City who have airboats.

So, why not put a shroud round the prop, it shoudl at least silence it
some?

No ear protection offered here. The boats are load at WOT but not
deafening.

http://www.evergladesholidaypark.com/airboats.html

Looks like each engine goes into a dual exhaust with some big mufflers.
When I rode, we were given ear muffs. The operator was wearing them also.



I just had a flashback to some television series of years ago that featured
cops or some agency roaring around on airboats.
Can't remember the name of the show.

Eisboch

Eisboch wrote:
"John H" wrote in message
...
On Tue, 09 Sep 2008 19:26:53 -0400, DK wrote:

wrote:
On Sep 8, 7:12 pm, wrote:
On Mon, 8 Sep 2008 18:32:05 -0400, "Eisboch" wrote:

wrote in message
...
WTF? Can't they put a muffler system on them, or is it the blades that
make the most noise?
----------------------------
Trust me. The engine is loud.
The prop is much, much, louder.
Eisboch
Down at Wootens the make the passengers and the drivers wear ear
protection. I don't know of anyone who doesn't.
I do know a couple guys down in Everglades City who have airboats.
So, why not put a shroud round the prop, it shoudl at least silence it
some?
No ear protection offered here. The boats are load at WOT but not
deafening.

http://www.evergladesholidaypark.com/airboats.html
Looks like each engine goes into a dual exhaust with some big mufflers.
When I rode, we were given ear muffs. The operator was wearing them also.



I just had a flashback to some television series of years ago that featured
cops or some agency roaring around on airboats.
Can't remember the name of the show.

Eisboch



Ahhh, the mind is the 2nd thing to go.

I think you are thinking about Flipper. The dad was a Park Ranger.