I'm trying to understand propellers
 

"Netsock" wrote in message
...
On Mon, 27 Feb 2006 12:52:27 -0500, Harry Krause
wrote:


I pointed this out last week. Also, the boat with the larger HP engine
will accelerate faster to its top speed:

Not true...flat out wrong

more torque, winds up to WOT
faster.

Huh? What does that mean? "WOT" is a throttle position, ie; "wide
open".

What kind of boat do you have again?
__

"It's just about going fast...that's all..."

http://home.columbus.rr.com/ckg/

Now don't go screwing this up, Netsock. We're making progress here.

RCE

I'm trying to understand propellers
 

"Shortwave Sportfishing" wrote in message
...


Ok, you win - I give in.

Pansy.

RCE :-)

I'm trying to understand propellers
 

I'm trying to understand propellers
 

If we use a 24" pitch propeller and there was no slippage, both boats would
travel 12,000 feet every minute at 6000 RPM.

With the same propeller on each boat the 250 hp boat would over rev at WOT.
So the helmsman would have to back off to keep it at 6000. The difference in
weight of the motors is about 30 lbs. Probably not going to be much of a
factor. The 250 might get to 6000 more quickly, but once at 6000 I think
both boats would be traveling at the same speed.

Thanks again,
Injam

"Injam" wrote in message
ink.net...
Hello,

I'm trying to understand propellers.

If you have two identical boats, but the outboard horsepower ratings are
different. One boat has a 200 hp and the other a 250 hp. Both motors have
the same Gear Ratio. If the propellers are identical and the RPM of the
outboard is the same on each boat. Say 6000 RPM. Because of the weight
advantage will the 200-hp boat be faster than the 250 hp? I'm thinking
less weight less slippage otherwise they would be going the same speed.



Sincerely,

Injam

I'm trying to understand propellers
 

"Helmsman" what was I thinking! I meant boat driver.

"Injam" wrote in message
ink.net...
If we use a 24" pitch propeller and there was no slippage, both boats
would travel 12,000 feet every minute at 6000 RPM.

With the same propeller on each boat the 250 hp boat would over rev at
WOT. So the helmsman would have to back off to keep it at 6000. The
difference in weight of the motors is about 30 lbs. Probably not going to
be much of a factor. The 250 might get to 6000 more quickly, but once at
6000 I think both boats would be traveling at the same speed.

Thanks again,
Injam

"Injam" wrote in message
ink.net...
Hello,

I'm trying to understand propellers.

If you have two identical boats, but the outboard horsepower ratings are
different. One boat has a 200 hp and the other a 250 hp. Both motors have
the same Gear Ratio. If the propellers are identical and the RPM of the
outboard is the same on each boat. Say 6000 RPM. Because of the weight
advantage will the 200-hp boat be faster than the 250 hp? I'm thinking
less weight less slippage otherwise they would be going the same speed.



Sincerely,

Injam

I'm trying to understand propellers
 

"Shortwave Sportfishing" wrote in message
...
On Mon, 27 Feb 2006 19:54:59 GMT, "Calif Bill"
wrote:


"Shortwave Sportfishing" wrote in message
. ..
On Mon, 27 Feb 2006 06:45:19 GMT, "Calif Bill"
wrote:


"Injam" wrote in message
hlink.net...
Why? If the propellers are turning at the same RPM and they have the
same
pitch, why would the 250 hp be faster?


"Harry Krause" wrote in message
. ..
Injam wrote:
Hello,

I'm trying to understand propellers.

If you have two identical boats, but the outboard horsepower
ratings
are different. One boat has a 200 hp and the other a 250 hp. Both
motors
have the same Gear Ratio. If the propellers are identical and the
RPM
of
the outboard is the same on each boat. Say 6000 RPM. Because of the
weight advantage will the 200-hp boat be faster than the 250 hp? I'm
thinking less weight less slippage otherwise they would be going the
same speed.

If the 200 hp engine is properly propped, the 250 hp engine will most
likely be underpropped with the same prop. The weight diff between a
200
hp and a 250 hp is not usually significant, certainly not enough t0
canel
out a 25% increase in hp.

Now, to your question...the 250 still might be faster, even if it is
underpropped.

It will be faster to the same speed. But, the 2 engines should not have
the
same pitch prop. The 250 hp will overspeed with the correct pitch for
the
200 hp. Same pitch and same RPM, other than a weight difference, both
boats
would be the same speed.

That's not the point. The point is that both run at 6000 RPM. Over
rev isn't an issue.

The issues as I understand them would point to horsepower being the
determination.

As long as you can turn that same prop at 6000 RPM the boat will move at
the
same speed. If I put your vette engine in my boat, at 3200 RPM I am still
at the same speed as my 330 mpi. It does not know that there is an extra
300 hp available.

Yeah, but yours is one of those goofy jet boats. :)

I understand what every body else is saying, I just don't agree.

Goofy jetboats? Try fishing this river in your pansy Ranger.
http://media.putfile.com/zigzag63

I'm trying to understand propellers
 

"Injam" wrote in message
ink.net...
If we use a 24" pitch propeller and there was no slippage, both boats
would travel 12,000 feet every minute at 6000 RPM.

With the same propeller on each boat the 250 hp boat would over rev at
WOT. So the helmsman would have to back off to keep it at 6000. The
difference in weight of the motors is about 30 lbs. Probably not going to
be much of a factor. The 250 might get to 6000 more quickly, but once at
6000 I think both boats would be traveling at the same speed.

Thanks again,
Injam


You got it. And the digital hour meter will keep excellent time.


RCE

I'm trying to understand propellers
 

Shortwave Sportfishing wrote:
Way, Jose..

I look at it this way. There is 50 more available horsepower at 6000
RPM. Thus, it makes total sense to me that given the same factors -
meaning inertia and momentum - that 50 additional horsepower driving
the props will give better speed.

I think you take perverse pleasure in being wrong. ;-)

The given scenario was at steady state equilibrium, no
acceleration. Both motors are producing essentially the same
power unless there is a slight weight/drag difference. The
200 would be at a higher percentage of max throttle than the
250 however.

-rick-

I'm trying to understand propellers
 

On Mon, 27 Feb 2006 15:32:53 -0500, Harry Krause
wrote:


Shouldn't you be attending to your job wiring up orifices at OSU,
Greenhalgh?

LOL! Don't ya love it when somebody is caught lying, they try to shift
the focus off of them, and onto someone else by fabricating lies?

It sure is hard keeping track of all those lies, isn't it Krause?

Ahhh...to think there's a village out there with no idiot...
__

"It's just about going fast...that's all..."

http://home.columbus.rr.com/ckg/

I'm trying to understand propellers
 

On Tue, 28 Feb 2006 14:28:01 -0500, Harry Krause
wrote:

As usual, you demonstrate your ignorance.

You work as a systems specialist in housing, food services and event
center facilities,

If you were half as smart as you try to put yourself off here, you
would know that OSU is a land grant University. State titles mean
little compared to the working title. "System Specialist" covers
virtually all IT workers, and has a salary range from 40k, all the way
well into 6 figures.

And yes, I work under HFSEC, in the Student Affairs IT Division.

And if you got that far, you would see that I hold an "appointment"
(rather than a position) and you did of course read that, right?

You did read the appointment description, right?

And since I'm considered a Public Servant, my salary is public
information...you did read that, right?

Or could it be you omitted that information, because it didn't fit
into your feeble smear agenda?

and you were recently advertising for an assistant to
hang network wire for you.

I've hired quite the number of people Krause, but none ever to pull
wire "for" me, rather the position I was filling.

Or maybe there's another GREENHALGH, CHRISTOPHER KENT.

Doubtful.

It's not much of a job for as ass as pretentious as you are.

As usual, your attempts to discredit with lies and accusations
backfire again. Just as you argue (notice I did not say debate) your
political agenda, you do so by mis-information, assumptions, lies,
omission, and mis-direction.

You have yet again been shown what you really are.

Thank you.

Your welcome.

Bye.

See ya!
__

"It's just about going fast...that's all..."

http://home.columbus.rr.com/ckg/