Damned airboats
 

On Sep 8, 1:33*pm, (Richard Casady) wrote:
On Mon, 8 Sep 2008 08:31:27 -0700 (PDT), wrote:
Normal IC aircraft engines aren't muffled, and the back pressure has
an affect on them if you try to.

Most, maybe all, of the planes I have experience with have had
mufflers. Includes radial engines from the thirties, and the usual
Piper, Beech, and Cessna planes in use from the forties on. Still
loud, every one of them.

Casady

From what loogie suggests, the engines may not run if muffled too
much. Is there ways to do it? Could these boats be made to be somewhat
sane? I know that with our bikes there are trick pipes that are very
loud, but several private tracks we frequent won't allow them. Guys
have to change pipes and rejet to ride there, but it can be done... I
don't think there is a lot of reason for a pleasure boat to be so
loud, although I do not have problems with loud vehicles in sanctioned
races, with proper permits and such...

Damned airboats
 

On Mon, 8 Sep 2008 10:53:44 -0700 (PDT),
wrote:

On Sep 8, 1:33*pm, (Richard Casady) wrote:
On Mon, 8 Sep 2008 08:31:27 -0700 (PDT), wrote:
Normal IC aircraft engines aren't muffled, and the back pressure has
an affect on them if you try to.

Most, maybe all, of the planes I have experience with have had
mufflers. Includes radial engines from the thirties, and the usual
Piper, Beech, and Cessna planes in use from the forties on. Still
loud, every one of them.

Casady

From what loogie suggests, the engines may not run if muffled too
much. Is there ways to do it? Could these boats be made to be somewhat
sane? I know that with our bikes there are trick pipes that are very
loud, but several private tracks we frequent won't allow them. Guys
have to change pipes and rejet to ride there, but it can be done... I
don't think there is a lot of reason for a pleasure boat to be so
loud, although I do not have problems with loud vehicles in sanctioned
races, with proper permits and such...

They require mufflers on sprint cars at many tracks.

Casady

Damned airboats
 

On Sep 8, 2:14*pm, (Richard Casady) wrote:
On Mon, 8 Sep 2008 10:53:44 -0700 (PDT),





wrote:
On Sep 8, 1:33*pm, (Richard Casady) wrote:
On Mon, 8 Sep 2008 08:31:27 -0700 (PDT), wrote:
Normal IC aircraft engines aren't muffled, and the back pressure has
an affect on them if you try to.

Most, maybe all, of the planes I have experience with have had
mufflers. Includes radial engines from the thirties, and the usual
Piper, Beech, and Cessna planes in use from the forties on. Still
loud, every one of them.

Casady

From what loogie suggests, the engines may not run if muffled too
much. Is there ways to do it? Could these boats be made to be somewhat
sane? I know that with our bikes there are trick pipes that are very
loud, but several private tracks we frequent won't allow them. Guys
have to change pipes and rejet to ride there, but it can be done... I
don't think there is a lot of reason for a pleasure boat to be so
loud, although I do not have problems with loud vehicles in sanctioned
races, with proper permits and such...

They require mufflers on sprint cars at many tracks.

Casady- Hide quoted text -

- Show quoted text -

Same with MX racing with N.E.M.A.. they have a sound check before
races but the levels are high. It is some of the private tracks where
they are more strict. Like I said, the NEMA races are sanctioned and
within the zoning and other guidelines as agreed with the local
communities.. But they do have limits.. My question is, is it possible
for these airboats to run at all within tolerable noise levels, or do
the engines just make that impossible? If so, maybe they need to find
an alternative power source, or a more suited tool.. Just because
something works, doesn't mean it's the best tool for the job. Who
hasn't used a screwdriver as a prybar;)

Damned airboats
 

On Sep 8, 1:33*pm, (Richard Casady) wrote:
On Mon, 8 Sep 2008 08:31:27 -0700 (PDT), wrote:
Normal IC aircraft engines aren't muffled, and the back pressure has
an affect on them if you try to.

Most, maybe all, of the planes I have experience with have had
mufflers. Includes radial engines from the thirties, and the usual
Piper, Beech, and Cessna planes in use from the forties on. Still
loud, every one of them.

Casady

Expansion chambers.

They aren't really mufflers, but are designed to make some
backpressure in normally aspirated engines. My uncle was an aviation
machinist. Been around small IC engined aircraft a lot!

Damned airboats
 

On Sep 8, 2:29*pm, wrote:
On Sep 8, 1:33*pm, (Richard Casady) wrote:

On Mon, 8 Sep 2008 08:31:27 -0700 (PDT), wrote:
Normal IC aircraft engines aren't muffled, and the back pressure has
an affect on them if you try to.

Most, maybe all, of the planes I have experience with have had
mufflers. Includes radial engines from the thirties, and the usual
Piper, Beech, and Cessna planes in use from the forties on. Still
loud, every one of them.

Casady

Expansion chambers.

They aren't really mufflers, but are designed to make some
backpressure in normally aspirated engines. My uncle was an aviation
machinist. Been around small IC engined aircraft a lot!

AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!
COULD THEY MAKE THEM QUIETER IF THEY WANTED TO?????????

Please answer me..... I gotta' know... sniff ;)

Damned airboats
 

On Sep 8, 2:35*pm, wrote:
On Sep 8, 2:29*pm, wrote:





On Sep 8, 1:33*pm, (Richard Casady) wrote:

On Mon, 8 Sep 2008 08:31:27 -0700 (PDT), wrote:
Normal IC aircraft engines aren't muffled, and the back pressure has
an affect on them if you try to.

Most, maybe all, of the planes I have experience with have had
mufflers. Includes radial engines from the thirties, and the usual
Piper, Beech, and Cessna planes in use from the forties on. Still
loud, every one of them.

Casady

Expansion chambers.

They aren't really mufflers, but are designed to make some
backpressure in normally aspirated engines. My uncle was an aviation
machinist. Been around small IC engined aircraft a lot!

AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!
COULD THEY MAKE THEM QUIETER IF THEY WANTED TO?????????

Please answer me..... * I gotta' know... sniff * ;)- Hide quoted text -

- Show quoted text -

There is not really any reason they could not have mufflers on the
engine. It would probably take a few mph off the top end. But much
of the noise is from the prop. Many simply bolt the prop to the
engine output so there is not a lot you can do with prop redesign.
More blades may allow you to run a smaller diameter but probably not a
lot smaller. So the prop tip speeds are still going to be pretty
high.

Damned airboats
 

On Sep 8, 2:35*pm, wrote:
On Sep 8, 2:29*pm, wrote:





On Sep 8, 1:33*pm, (Richard Casady) wrote:

On Mon, 8 Sep 2008 08:31:27 -0700 (PDT), wrote:
Normal IC aircraft engines aren't muffled, and the back pressure has
an affect on them if you try to.

Most, maybe all, of the planes I have experience with have had
mufflers. Includes radial engines from the thirties, and the usual
Piper, Beech, and Cessna planes in use from the forties on. Still
loud, every one of them.

Casady

Expansion chambers.

They aren't really mufflers, but are designed to make some
backpressure in normally aspirated engines. My uncle was an aviation
machinist. Been around small IC engined aircraft a lot!

AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!
COULD THEY MAKE THEM QUIETER IF THEY WANTED TO?????????

Please answer me..... * I gotta' know... sniff * ;)- Hide quoted text -

- Show quoted text -

I'm guessing they could at the risk of performance, especially the
inlines. Radials may be harder because of the piping involved. W's not
used much anymore, and X's, quite rare may be different!

Damned airboats
 

On Mon, 8 Sep 2008 11:25:07 -0700 (PDT),
wrote:

On Sep 8, 2:14*pm, (Richard Casady) wrote:
On Mon, 8 Sep 2008 10:53:44 -0700 (PDT),





wrote:
On Sep 8, 1:33*pm, (Richard Casady) wrote:
On Mon, 8 Sep 2008 08:31:27 -0700 (PDT), wrote:
Normal IC aircraft engines aren't muffled, and the back pressure has
an affect on them if you try to.

Most, maybe all, of the planes I have experience with have had
mufflers. Includes radial engines from the thirties, and the usual
Piper, Beech, and Cessna planes in use from the forties on. Still
loud, every one of them.

Casady

From what loogie suggests, the engines may not run if muffled too
much. Is there ways to do it? Could these boats be made to be somewhat
sane? I know that with our bikes there are trick pipes that are very
loud, but several private tracks we frequent won't allow them. Guys
have to change pipes and rejet to ride there, but it can be done... I
don't think there is a lot of reason for a pleasure boat to be so
loud, although I do not have problems with loud vehicles in sanctioned
races, with proper permits and such...

They require mufflers on sprint cars at many tracks.

Casady- Hide quoted text -

- Show quoted text -

Same with MX racing with N.E.M.A.. they have a sound check before
races but the levels are high. It is some of the private tracks where
they are more strict. Like I said, the NEMA races are sanctioned and
within the zoning and other guidelines as agreed with the local
communities.. But they do have limits.. My question is, is it possible
for these airboats to run at all within tolerable noise levels, or do
the engines just make that impossible? If so, maybe they need to find
an alternative power source, or a more suited tool.. Just because
something works, doesn't mean it's the best tool for the job. Who
hasn't used a screwdriver as a prybar;)

As soon as you start enlarging the airframe to accommodate large
effective mufflers, they will starting impacting speed and range.
They will have weight regardless of any drag penalty. Earplugs or
radio headsets are much cheaper. During the SEA war games, the CIA
had a powered sailplane with effective mufflers and a zillion blade
low speed prop and which was nearly silent.

Casady

Damned airboats
 

On Mon, 8 Sep 2008 11:56:46 -0700 (PDT), wrote:

On Sep 8, 2:35*pm, wrote:
On Sep 8, 2:29*pm, wrote:





On Sep 8, 1:33*pm, (Richard Casady) wrote:

On Mon, 8 Sep 2008 08:31:27 -0700 (PDT), wrote:
Normal IC aircraft engines aren't muffled, and the back pressure has
an affect on them if you try to.

Most, maybe all, of the planes I have experience with have had
mufflers. Includes radial engines from the thirties, and the usual
Piper, Beech, and Cessna planes in use from the forties on. Still
loud, every one of them.

Casady

Expansion chambers.

They aren't really mufflers, but are designed to make some
backpressure in normally aspirated engines. My uncle was an aviation
machinist. Been around small IC engined aircraft a lot!

AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!
COULD THEY MAKE THEM QUIETER IF THEY WANTED TO?????????

Please answer me..... * I gotta' know... sniff * ;)- Hide quoted text -

- Show quoted text -

There is not really any reason they could not have mufflers on the
engine. It would probably take a few mph off the top end. But much
of the noise is from the prop. Many simply bolt the prop to the
engine output so there is not a lot you can do with prop redesign.
More blades may allow you to run a smaller diameter but probably not a
lot smaller. So the prop tip speeds are still going to be pretty
high.

I just spoke with a young man in Orlando. He's at Don George
Aircraft Engines & Parts
Orlando, Florida 32805
407.422.0188

I remembered that the airboat I rode on had a Lycoming engine, which gave
me a starting place. According to the guy I spoke with, the law in Florida
requires mufflers on *all* airboat engines. The loudness comes from the
propellor. Problem solved.

Damned airboats
 

On Sep 8, 3:33*pm, John H wrote:
On Mon, 8 Sep 2008 11:56:46 -0700 (PDT), wrote:
On Sep 8, 2:35*pm, wrote:
On Sep 8, 2:29*pm, wrote:

On Sep 8, 1:33*pm, (Richard Casady) wrote:

On Mon, 8 Sep 2008 08:31:27 -0700 (PDT), wrote:
Normal IC aircraft engines aren't muffled, and the back pressure has
an affect on them if you try to.

Most, maybe all, of the planes I have experience with have had
mufflers. Includes radial engines from the thirties, and the usual
Piper, Beech, and Cessna planes in use from the forties on. Still
loud, every one of them.

Casady

Expansion chambers.

They aren't really mufflers, but are designed to make some
backpressure in normally aspirated engines. My uncle was an aviation
machinist. Been around small IC engined aircraft a lot!

AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!
COULD THEY MAKE THEM QUIETER IF THEY WANTED TO?????????

Please answer me..... * I gotta' know... sniff * ;)- Hide quoted text -

- Show quoted text -

There is not really any reason they could not have mufflers on the
engine. *It would probably take a few mph off the top end. *But much
of the noise is from the prop. *Many simply bolt the prop to the
engine output so there is not a lot you can do with prop redesign.
More blades may allow you to run a smaller diameter but probably not a
lot smaller. *So the prop tip speeds are still going to be pretty
high.

I just spoke with a young man in Orlando. He's at Don George
Aircraft Engines & Parts
Orlando, Florida 32805 *
407.422.0188

I remembered that the airboat I rode on had a Lycoming engine, which gave
me a starting place. According to the guy I spoke with, the law in Florida
requires mufflers on *all* airboat engines. The loudness comes from the
propellor. Problem solved.- Hide quoted text -

- Show quoted text -

Sounds to me like there is not really a reasonable way to quiet the
prop, without a complete retool.. Ok, as long as they are trying I
guess most will have to live with it until noise limits are imposed
and someone works out the technology to be efficient and affordable..
Might be, it can't be done, but not everyone can own a jet either;)