Paddlewheel versus Propeller
Dan Bollinger
between a Paddlewheeler and a Propeller driven boat to see which one was
superior? References would be great. The reason I ask is because Junkyard
Wars is considering repeating this contest as a challenge this season.
thanks, Dan
Ralph Naylor
competed in 1845. Here's a starting point for you -
http://www.warships.net/factfile-Q&A/page1.htm
"Dan Bollinger" <danbol...@insightbb.com> wrote in message
news:diMg8.76870$vP.2...@rwcrnsc51.ops.asp.att.net...
mec...@home.net
I've alway thought a paddlewheel could be more efficient than a prop.
I assumed they went out of style because they were large and bulky and
fuel was cheap. I think there could also be problems with wave,
suface interactions, and I can't see it working well for a high speed
planing hull.
-
Glenn Ashmore
mechanism being a lot heavier, I would suspect that paddle wheels will
waste a lot of energy producing a lot more side eddies than a prop will
and as the speed increases it will start throwing more water up than back.
As for Junkyard wars, the only thing the paddle wheel has going for it
is less draft. As it is highly unlikely that they will convence the
owner of that antique tripple compound that siezed up for lack of oil
last year to lend it out again, they will probably seed the yard with a
couple of gas engines so I would go with a prop unless the contest is in
water only a few inches deep. But then one of the teams will probably
luck into a discarded Arneson surface drive. ;-)
mec...@home.net wrote:
--
Glenn Ashmore
I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
D MacPherson
propulsive efficiencies as much as 15% higher than propellers (when both are
optimially designed). The feathering nature of the blade entering and
exiting the water with minimum drag is the key (i.e., reduced blade "slip"
relative to the water). The lower velocity of the propulsor relative to the
ship velocity also contributes somewhat. There was extensive testing done in
Germany in the 50's in an effort to improve the inland river fleet. It never
really caught on because of the greater mechanical complexities (relative to
screw propellers), weight, and structural concerns (stress, weight) as boat
speeds increased.
Regards,
Don
Donald M. MacPherson
VP Technical Director
HydroComp, Inc.
email: d...@hydrocompinc.com
http://www.hydrocompinc.com
tel (603)868-3344
fax (603)868-3366
"Glenn Ashmore" <gash...@mindspring.com> wrote in message
news:3C83CDF7...@mindspring.com...
JAXAshby
>I've alway thought a paddlewheel could be more efficient than a prop
I understood paddlewheels were very much less efficient. Paddlewheel boats are
still made on occasion (party type boats, sight-seeing boats), but the reports
always were that they didn't work as well. I haven't seen hard data.
barry lawson
cwg
But practially, props always have the advantage. They are simpler, lighter,
and less moving parts to cause problems and loss of efficiency.
High-performance human-powered craft always use props instead of paddles for
this reason.
<mec...@home.net> wrote in message news:3c83c565...@news.verizon.net...
Martin Keivers
screw won hands down
Dan Bollinger wrote in message ...
Tucson QA 78
Dan Bollinger
challenge producer.
From the date and the fact that the paddlewheel builder was in the UK, I
suspect that it wasn't a feathering blade. Too bad, the results might have
been reversed.
"Ralph Naylor" <ashb...@hotmail.nospamcom> wrote in message
news:nONg8.14479$106.1...@bgtnsc05-news.ops.worldnet.att.net...
Dan Bollinger
speed. I can believe it.
<mec...@home.net> wrote in message news:3c83c565...@news.verizon.net...
Dan Bollinger
and feathering wheels instead of a propeller powered by steam turbines.
Operating costs were estimated to be identical. They noted that the reduced
space and vibration of a paddlewheel made the deciding factor. Its top
speed was 23 mph in the trial run. Dan
"Glenn Ashmore" <gash...@mindspring.com> wrote in message
news:3C83CDF7...@mindspring.com...
William R. Watt
> This experiment was repeated on uk tv by a guy called Adam Hart-Davies - The
> screw won hands down
Like his work. Ontario educational TV is currently broadcasting his films
on Roman occupation of UK. Neat engineering.
--
------------------------------------------------------------------------------
National Capital FreeNet www.ncf.ca Ottawa's free community network
website: www.ncf.ca/~ag384 "Tank, take me in."
------------------------------------------------------------------------------
Ralph Naylor
surface-piercing prop. Brings to mind the guys who tried to use a lawn
mower as a hedge trimmer !
"Glenn Ashmore" <gash...@mindspring.com> wrote in message
news:3C83CDF7...@mindspring.com...
John McCoy
>I've head that paddles are more efficient at high resistant loads at low
>speed. I can believe it.
That would seem likely, at very very slow speeds.
I'd always heard that the primary advantage of a sidewheeler was that
they could sail squares around other boats.
John
HLAviation
>are
>still made on occasion (party type boats, sight-seeing boats), but the
>reports
>always were that they didn't work as well. I haven't seen hard data.
I've run a couple conventional paddle wheelers, both stern and side, they work
ok. There are modern padlewheelers in a way, take a look at a Voith Sceider
Cyclodial drive, they work great. My favorite drive for ship assist.
http://hometown.aol.com/hlaviation/
brad
I copied this text from www.warships.net/factfile-Q&A/page1.htm
How did the Royal Navy decide between the paddle and the screw
propellor for ship propulsion?
The mid 19th century saw the beginning of a period of dramatic change
in the design and propulsion in ships of all kinds. One of these which
developed from the advent of steam engines was how best to translate
this new power into forward movement. The screw or propeller had been
invented and this was a rival to the side paddles which had been in
use for some time. A major issue had to be decided, however, as
paddles posed design and construction problems in fighting ships
especially. But were screws or paddles the most efficient?
Supporters of each had vied with each other for some time but the time
had come for a series of tests.
As a result two sloops of roughly the same power and weight were
chosen. HMS Rattler was fitted with a screw and HMS Alecto was a
paddle ship. In 1845 three tests were set. In the first the two ships
raced each other in smooth sea conditions over an 80 mile course.
Rattler beat Alecto by 23 and a half minutes. The second test was a
race into a heavy sea over 60 miles. Rattler won this by 40 minutes.
The third test consisted of a 'tug of war'. The two ships pulled
against each other with hawsers attached to their sterns. Rattler won
this also, pulling Alecto along at 2 and a half knots.
The issue was conclusively decided and it from then onwards that major
Royal Navy ships were built with screw propulsion. Paddle ships
continued to be used however for such tasks as harbour work.
Doug
small paddle wheel designed to be completely underwater, like a prop
is? How would that compare to a prop assuming you could get it to spin
at the same speed?
William R. Watt
pushing the boat forward wouldn't the top be pushing it backward?
I do think a disadvantage of the paddle wheel is surface turbulence. The
screw is under the hull where the hull stops the water from splashing up
and losing its thrust. Probably similar to the contained turbulance at the
top of keels and daggerboards. A marine engineer would probably know.
Pat Ford
There is a technology that uses something like this. The "paddle
wheel" is horizontal on the bottom of hull. I assume there are two
wheels. The "feathering" of the paddles can be controlled resulting in
extreme turning ability. They can spin without moving forward. The
technology is used in some tugs on Puget Sound and no doubt elsewhere.
It is a German invention.
Doug
> if the paddle wheel were completely submerged then while the bottom is
> pushing the boat forward wouldn't the top be pushing it backward?
>
Rick
It is an American invention of a man from Seattle. The American marine
industry thought it was a bad idea, the Germans thought otherwise and
now sell the units to Seattle tugboat companies.
Rick
mec...@home.net
resistance or "skin friction" increases with the cube of the velocity
and the velosity of that blade tip is usually very high. There is a
spinning column of water behind a prop. I think dual props (one
behind the other) were created for this reason. There is also a shaft
and strut or a outdrive foot which have significant drag.
The traditional paddlewheels I've seen are very crude things. They
have flat blades that are often wood planks. I think some modern
engineering would have to be applied to really give it a fair shake.
Any splashing would hurt the efficiency. I was thinking that a curved
blade could be designed that could enter and exit the water cleanly.
An articulating blade would do even better but would add alot of
complication. I have an articulating design that I know would enter
and exit cleanly but it is a contraption and I would only consider it
for a human powered boat.
With that in mind I picture the thin curved blade of a paddlewheel
entering the water, pushing it, then lifting out. Then I picture that
tornado of spinning water behind a prop.
You can pretty much judge the efficiency of a boat hull by its wake.
I recently built an 18' displacement power catamaran. I put a Honda
8hp centered between the hulls. There is enough space between the
motor and the hulls that you can see the separate disturbances behind
the boat. I think this is the first time I've ever really been able
to isolate how much water disturbance behind the boat is due to the
motor. At 12 knots there is a very thin small wake behind each 18/1
hull. The motor, on the other hand is throwing up a shower of spray
and has more of a wake behind it than both hulls combined.
I still don't want a monster wheel on my boat. I would like to try it
as an experiment though.
-Mark
mec...@home.net
>There is a technology that uses something like this. The "paddle
>wheel" is horizontal on the bottom of hull. I assume there are two
>wheels. The "feathering" of the paddles can be controlled resulting in
>extreme turning ability. They can spin without moving forward. The
>technology is used in some tugs on Puget Sound and no doubt elsewhere.
>It is a German invention.
>
I think this is what I saw once on a research ship that was running
some sort of dive exposition. It was in a documentary on TV. It
looked like a couple of egg beaters on the bottom of the boat. They
claimed it could be be used to hold the boat in place when they were
in water too deep to anchor. I've been wanting to find out for years
what that was and how it worked. It must not have worked very well
since I havn't seen it again. I don't even know what words to use to
try to search it on the net.
You know that pedal powered kayak from Hobie Cat? It has two fins
tthat sweep in opposing directions. I wander what the efficiency of
that is as a propulsion device. Someone might want to try hooking a
motor to something like that. The concept is similar to a skulling
oar.
-Mark
Rick
after the German company that bought the patent from Frederick Kirsten
and developed the concept to what it is today.
Rick
Gordon Couger
"brad" <bpb...@yahoo.com> wrote in message
news:7a842bd2.02030...@posting.google.com...
> "Dan Bollinger" <danbol...@insightbb.com> wrote in message
news:<diMg8.76870$vP.2...@rwcrnsc51.ops.asp.att.net>...
> > Does anyone have any information on a contest held in the late 1800's
> > between a Paddlewheeler and a Propeller driven boat to see which one was
> > superior? References would be great. The reason I ask is because
Junkyard
> > Wars is considering repeating this contest as a challenge this season.
> > thanks, Dan
>
> I copied this text from www.warships.net/factfile-Q&A/page1.htm
>
>
> How did the Royal Navy decide between the paddle and the screw
> propellor for ship propulsion?
> The mid 19th century saw the beginning of a period of dramatic change
> in the design and propulsion in ships of all kinds. One of these which
> developed from the advent of steam engines was how best to translate
> this new power into forward movement. The screw or propeller had been
> invented and this was a rival to the side paddles which had been in
> use for some time. A major issue had to be decided, however, as
> paddles posed design and construction problems in fighting ships
> especially. But were screws or paddles the most efficient?
>
venerable to gunfire than a screw. Considering the tactics used in WWI maybe
not.
--
Gordon
Gordon Couger
Stillwater, OK
www.couger.com/gcouger
John213a
> propellor for ship propulsion? >>
One of the considerations was that with side paddle wheels, when a ship on the
ocean rocks from side to side with the waves, the paddle wheel on one side gets
pulled up out of the water, while the one on the opposite side is pushed deeper
into the water, both causeing problems. With a propeller, the rocking does not
cause any major problem. Paddle wheels on the other hand were very usefull
in shallow sheltered waters where the rocking of a ship due to waves and wind
were negliable, and propellers having to be on the bottom of the boat were more
likely to foul on shallow bottom where a paddle wheel could just skim the
surface. The choice between the two as reagard their respective efficiencies
has to be more in relation to the waters they will travel on. So the Royal
Navy decided eventually for the screw propellor since they were a sea going
Navy, and on the Mississippi, paddle wheels ruled the day.
Dan Bollinger
> engineering would have to be applied to really give it a fair shake.
> Any splashing would hurt the efficiency. I was thinking that a curved
> blade could be designed that could enter and exit the water cleanly.
> An articulating blade would do even better but would add alot of
> complication.
Depends on your definition of 'modern'! The European riverboat fleet was
fitted with feathering sidewheels and curved blades around 1890. Besides
efficiencies of 80% they are the only water drive that has less draft than
the boat.
Dan Bollinger
Exactly. Here is the website, check out the animation, too.
http://www.voith-schiffstechnik.com/shared/set_main.htm
JAXAshby
>spinning column of water behind a prop. I think dual props (one
>behind the other) were created for this reason.
counter-rotating props were developed for torque reasons. They are less
efficient than a single prop (same hp) because the second prop works in
turbulent water.
D MacPherson
CRP systems recover rotational energies imparted to the water from a single
propeller. An optimized CRP system vs an optimized single prop (for a common
maximum diameter) is on the order of 8%-10% more efficient.
Regards,
Don
Donald M. MacPherson
VP Technical Director
HydroComp, Inc.
email: d...@hydrocompinc.com
http://www.hydrocompinc.com
tel (603)868-3344
fax (603)868-3366
"JAXAshby" <jaxa...@aol.com> wrote in message
news:20020306101727...@mb-ml.aol.com...
Mikedemetz
was told .
They use 3 units. 2 in back 1 in front.
They also use a quick change system that can be don in water.
Mike
********************
JAXAshby
statement such as "... on the order of 8%-10% more efficient".
Nobody with an actual engineering background would make that kind of statement.
In fact, just making that statement during an engineering job interview would
end the interview right then and there.
D MacPherson
forms; over 450 clients worldwide (including every flavor of propeller and
engine builder you'd care to name), over 2000 technical references in my
library...
Yeah, what was I thinking...
Go away.
"JAXAshby" <jaxa...@aol.com> wrote in message
news:20020306132332...@mb-bh.aol.com...
Andrew
> PUL LEAZE don't begin to claim engineering expertise while making a
foolish
> statement such as "... on the order of 8%-10% more efficient".
>
Which for instance is why so many aircraft used conta rotating props, for
thier inefficiency......
I'm sure you can provide some proof other than off the subject emails of
course? Or is this the same game as in Rec.boats?
Rick
and bulkers up to 250,000 tons and obtained a 14-15 percent energy
savings.
The new generation of containerships will require over 100,000
horsepower and the use of CRP is one idea of how to transmit that power
since current propellers appear to have a practical limit of around 100K
hp.
Rick
Giles Morris
> Let's see... 20 years evaluating, designing, testing propulsors
> "JAXAshby" <jaxa...@aol.com> wrote
(The usual garbage>)
<Plonk> <Flush>
Well, that brightened up the day.
Giles
William R. Watt
water at high speed. ribs on the belt are paddles.
also have seen circular outboard motor wells where motor rotates 360 deg.
interesting means of motorized propulsion.
Giles Morris
> Which for instance is why so many aircraft used conta rotating props, for
> thier inefficiency......
I thought it was because the power outputs involved became so large that it
was difficult to push so much through a single prop. Could that not have
been part of the story?
Giles Morris
De Clarke
hand-crank paddlewheel for small boats.
--
.............................................................................
:De Clarke, Software Engineer UCO/Lick Observatory, UCSC:
:Mail: d...@ucolick.org | :
:Web: www.ucolick.org | Don't Fear the Penguins :
:1024D/B9C9E76E F892 5F17 8E0A F095 05CD EE8B D169 EDAA B9C9 E76E:
JAXAshby
So WFT did you use the term "... on the order of 8%-10% more efficient"?
you're like the guy who posted here that he owned and flew a famous "acrobatic"
airplane named after a tennis shoe.
the downfall of "call me Fishmeal" was in the end his statement very much like
yours.
Geesh, man. "... on the order of 8%-10% more efficient"? Which fricking
engineering school did you say you knew the name of? MIT? Cal Tech?
Stanford?
JAXAshby
face, and every last person who ever studied engineering knew that before they
were even a week into engineering schools. Its use makes an instant liar of
the speaker's claim to engineering background.
It's like a guy at a job interview claiming high level executive experience and
accomplishments but the dude is wearing cowboy boats.
Nyet.
JAXAshby
>
>> Which for instance is why so many aircraft used conta rotating props, for
>> thier inefficiency......
Sooooo many? How many is soooooo many? I've been to Oshkosh many times (where
upwards of 10% of all aircraft in the USA are on the field for several days)
and have yet to see even one such aircraft.
JAXAshby
of I'd only heard that whatever the sources and that I had seen no hard data.
Sorry, I didn't make it more clear. Now, I heard that paddlewheels may under
certain conditions be more efficient. If I ever repeat that I will make clear
that I just heard that.
Schöön Martin
> The traditional paddlewheels I've seen are very crude things. They
> have flat blades that are often wood planks. I think some modern
> engineering would have to be applied to really give it a fair shake.
> Any splashing would hurt the efficiency. I was thinking that a curved
> blade could be designed that could enter and exit the water cleanly.
> An articulating blade would do even better but would add alot of
> complication. I have an articulating design that I know would enter
> and exit cleanly but it is a contraption and I would only consider it
> for a human powered boat.
>
This has been done and it turned out to be quite successful. I don't know
an URL from the top of my head but go looking for human powered
vehichles. The name of the boat I have in mind is Clementine by the
way. She was designed by a student team from a German university in
the 1980s. You can also search for "af Chapman II". She is a human
powered hydrofoil so don't expect paddlewheels but she will lead
you to URLs where you are likely to find Clementine.
Have fun,
--
========================================================================
Martin Schöön <Martin...@ericsson.com>
"Problems worthy of attack
prove their worth by hitting back"
Piet Hein
========================================================================
D MacPherson
my word for it. In the interest of providing additional technical data - for
those really interested in digging into this topic - I have listed some
references (with brief quotes). These references make for a pretty thorough
overview of the topic.
1. Principles of Naval Architecture, vol 2, p 232
"higher efficiencies than single screw propellers"
2. Park, Y.S. "Development of New Contra-Rotating Propeller System High
Efficiency Propulsion System Based on Advanced Technology", The Sciences of
Ships, Aug 1996
"CRP is a high efficiency propulsor system that recovers the rotational
energy lost in the flow generated by the fore propeller by the aft propeller
by contra-rotating them..."
3. van Beek, T. and de Jong, H., "Advanced Propulsion Through Counter
Rotating Propellers", Int'l Marine Design Conference, Delft Netherlands, May
1994 (the authors are from Lips Propellers)
Their opening words are, "Counter Rotating Propellers (CRP) are
recognized energy savers. Propulsive efficiency is increased by 5 to 15
percent in comparison with conventional drives."
4. Nishiyama, S., Sakamoto, Y., Ishida, S., Fujino, R., Oshima, M.,
"Development of Contrarotating-Propeller System for JUNO - a 37,000-DWT
Class Bulk Carrier", SNAME Transactions, 1990
In their abstract, "The ballasted sea trials showed 15% power-saving
effect of the CRP system on Juno compared with the conventional propeller
system and a similar effect was confirmed during fully loaded voyages."
5. Perez-Gomez, G. and Gonzalez-Adalid, J., "Contrarotating and Tandem CLT
Properties", SNAME Propeller Symposium, 1994
"an improvement of 11.3% in the propeller thrust"
6. Fujino, R., et al, "A Practical Design Method for Contrarotating
Propeller Systems", Proceedings ICCAS '82, Annapolis, Jun 1982
"It is revealed that the contrarotating propeller ensures approximately
8% enhancement of propeller efficiency over the single propeller." And
specifically, "the presence of rotational energy accounts for roughly 12%
decrease of propeller efficiency. Recalling that the enhancement of the
propeller efficiency ensured by the adoption of the contrarotating propeller
was 8% despite almost complete elimination of the rotating flow, the
difference with the 12% accounted for above can be ascribed to the
additional friction inevitably introduced by the increase of overall
propeller surface area."
And finally, just to show that this is not a new concept, two of the
landmark references on CRP are
7. Morgan, W.B., "The Design of Counterrotating Propellers Using Lerbs'
Theory", SNAME Transactions, 1960. (Bill ran the Navy's propeller R&D for
years.)
8. Hadler, J.B., Morgan, W.B., and Meyers, K.A., "Advanced-Propeller
Propulsion for High-Powered Single-Screw Ships", SNAME Transactions, 1964
Regards,
Don
Donald M. MacPherson
VP Technical Director
HydroComp, Inc.
email: d...@hydrocompinc.com
http://www.hydrocompinc.com
"JAXAshby" <jaxa...@aol.com> wrote in message
news:20020306172507...@mb-mt.aol.com...
JAXAshby
covers does not make you an engineer.
Kriste almighty man! You used an extremely elemental term incorrectly. You
expect *anyone* to believe you know what you're talking about?
Let's say you come to this board claiming to be an expert in diesel engines but
then tell us how to check the spark plugs. Would anybody believe you know
diddly about diesels?
So, why you want us to believe that any engineer doesn't know what "on the
order of" means? (hint, to an engineer when discussing an engineering subject
ain't no way in hell it means "about")
Dan Bollinger
amiss with his statement about CRPs being more efficient. It sounds to me
like you are taking him to task on a minor grammatical aspect. Sometimes I
do the same thing when people use 'accurate' and 'precise' interchangeably.
Frankly, I don't understand what you have been saying. But then I'm not an
engineer! Oh, and while we are on the subject, notice that this is a REC
group, not an ENGR bbs. Perhaps your complaint holds water over at
sci.engr.marine.hydrodynamics, but here at rec.boats.building we don't
sharpen our pencils quite that fine. Could it be that you have an
overwhelming desire to 'be right' and now that Don has supplied citations
for his statement you are searching to save face? Just a thought, reject it
if it doesn't apply...
Dan Bollinger
Industrial Designer
Purdue University
"JAXAshby" <jaxa...@aol.com> wrote in message
news:20020307093555...@mb-cu.aol.com...
Dan Bollinger
such a mechanism. They are called feathering wheels. It is a simple
parallelogram (actually a rhomboid) mechanism. Just like the mechanism that
drives the pistons on radial engines.
http://www.claycritters.com/misc/f87p272.gif
"Schöön Martin" <era...@yellow320.era-a.ericsson.se> wrote in message
news:s5zn0xk...@yellow320.era-a.ericsson.se...
JAXAshby
about the subject, and candidly, find it only an interesting item for a moment.
However, I am (let's use the correct word here) offended that some clown
(again, correct word) claims engineering expertise and THEN grossly missuses an
extremely elemental engineering term. The guy was claiming expertise he didn't
have. Just like the diesel "expert" who tells you of the need to clean the
spark plugs on a diesel (Subastian Junger's mistake).
I come here to learn and am offended by frauds, engineering or otherwise.
Jerry
About the only thing I know about Webb is that as a Scholarship only school
they don't need to advertise anywhere. There's a waiting list. They are one
of only a few fully accredited dedicated NA and marine schools in the world.
But you knew that, right? As an aside in what engineering dicipline did you
graduate from and where?
You've chosen to ignore a simple statement that 'contrarotating propellers
are more efficient' throughout your last posts, even though there's facts
provided that suggest they are. Instead you respond with your usual style of
off subject and unsupported allegation and pedantic insistance on grammer or
sytax. As you did with pink foam for core composite and piston speed's,
both classics. That ignores what's on Rec.boats, but then you're on my
killfile there along with a lot of other people I would think.
Personally I found <http://www.hydrocompinc.com/propx.htm> a worthwhile
visit, a shame you didn't. A quick search to see if this statement that so
inflames you is true turned up several references, found in about two
minutes on Google that a two year old could read, such as;
http://www.mesj.or.jp/bunken/english/text/mv20n011992p21.html
If you need to learn how to read other posts properly or the sites
referenced I'd recommend the phonics system.
As to contraprops on aircraft there was at least one Mustang running a
contra at Oshkosh in Gold trophy for some years. As suggested by another
poster, contrarotating props were developed for aircraft to get the power
capacity without hitting supersonic tip speeds and materials problems, or to
improve control. As a bonus they were also found to be efficient, due to
some ability to recover otherwise wasted energy from the front prop with the
second. External fan engines are being developed by NASA for airline use,
and guess what? they are counterrotating because they are more efficient.
Tupolev built the Bear as a turboprop because at the time that was the only
way they could get the thing off the ground and get the range they needed.
Why in the 50's where almost all feeder airliner turboprops contrarotating?
they were most efficient means for the given fuel at the time. Since
range per given quantity of fuel is to most normal peoples view a measure of
efficiency I await your answers with interest.
On the subject of answers its also interesting that most people make
suggestions and usually, polite considered, intellegent or humorous
responses. Yours are interesting in that your frequently questionable
rebuttals are followed by off topic and unsubstantiated abuse as your
assertion on the subject. A quick google search produces some laughable
references if anyones interested. Such as this;
"JAXAshby and his underwear photos -- JAX was an irritating poster who was
not only rude, condescending, and self-absorbed, but he was also certain
that he was God's gift to women. His homepage has some disturbing pictures
of him, including one of him in a pair of bikini underwear. He insisted that
most women found him very attractive, and quoted one as calling him "all
beefcake--and a boat" (he owns a boat?)"
Just one persons opinion of course and we'll all make our own. Thankfully we
have a killfile.
"JAXAshby" <jaxa...@aol.com> wrote in message
news:20020307093555...@mb-cu.aol.com...
Andrew
You said 'counter-rotating props were developed for torque reasons. They
are less
efficient than a single prop (same hp) because the second prop works in
turbulent water'
The poster you've an issue with said 'CRP systems recover rotational
energies imparted to the water from a single propeller. An optimized CRP
system vs an optimized single prop (for a common maximum diameter) is on the
order of 8%-10% more efficient'
Since then you've said nothing about this subject apart from claiming some
misuse of elemental engineering terms.
So for an uneducated ( unless you include an Aero. Eng. BSc. ) what in the
second quote above is incorrect?
"JAXAshby" <jaxa...@aol.com> wrote in message
news:20020307101358...@mb-mq.aol.com...
D MacPherson
of Naval Architecture. (Don't remember a matchbook, though...) I thought I'd
put down a few links in case anyone has a son or daughter that is thinking
of a naval architecture career and is looking at schools.
http://www.webb-institute.edu/about_webb/fast_facts.php
Webb doesn't toot its own horn too much, but you can find some interesting
info about things like rankings and endowment on other sites.
http://www.alumnifriends.mines.edu/news_and_events/one_of_the_nations_best/d
efault.htm
http://www.usnews.com/usnews/edu/college/rankings/engineering/nophd/topprogs
_nophd.htm
http://www.northcanton.sparcc.org/~mwg1nc/scholar.html
http://www.earlymodern.com/reference/rankings/price/endowment_1.htm
Regards,
Don
Donald M. MacPherson
VP Technical Director
HydroComp, Inc.
email: d...@hydrocompinc.com
http://www.hydrocompinc.com
"JAXAshby" <jaxa...@aol.com> wrote in message
news:20020307093555...@mb-cu.aol.com...
>
> donny, "graduating" from some place that advertises on the backs of
matchbook
> covers does not make you an engineer.
>
> >"JAXAshby" <jaxa...@aol.com> wrote in message
> >news:20020306172507...@mb-mt.aol.com...
> >> Really?
> >>
JAXAshby
JAXAshby
much in 4 years as every other institution teaches engineering students in less
than a week?
Even this moment, it seems, you STILL don't know what the term "on the order
of" means, something that ALL engineering people know, and know by the end of
their first week of study.
It's elemental, don. Basic. you might want to learn the term if you wish to
claim engineering expertise in the future.
btw, diesel engines don't have spark plugs (unless their military multi-fuel
engines, but that's a different story)
JAXAshby
system. This can be a tremendous advantage in high-hp applications. The
problem with counter-rotating props is that the second prop operates in "dirty"
air/water.
If you -- the "Aero. Eng. BSc." -- check it out, you'll find the Cessna 336/337
has a greater service ceiling on the rear engine than on the forward engine.
How come you didn't know this stuff about props?
D MacPherson
perfect, but it works for me (and the folks at Roget's, apparently).
http://www.bartleby.com/62/52/A0085200.html
Regards,
Don
Donald M. MacPherson
VP Technical Director
HydroComp, Inc.
email: d...@hydrocompinc.com
http://www.hydrocompinc.com
"JAXAshby" <jaxa...@aol.com> wrote in message
news:20020307110838...@mb-mq.aol.com...
JAXAshby
Next you'll be quoting The National Enquirer for international economic advice.
Listen up, Don. "... on the order of..." has a specific mathematical meaning
that is important in engineering. Engineers use the term correctly from the
time they are in their first week of school on. It is in fact a similar
situation as diesel mechanics knowing the diesels don't have spark plugs. It
is important information and is used as such. At least by engineers, and most
certainly when discussing engineering subjects.
Roget's as a source of engineering knowledge? Really?
Tom
in engineering for the term "... on the order of..." ?
"JAXAshby" <jaxa...@aol.com> wrote in message
news:20020307130754...@mb-ba.aol.com...
Meindert Sprang
> Dan, I'm not debating the paddlewheel vs prop. I just don't know very
much
> about the subject, and candidly, find it only an interesting item for a
moment.
> However, I am (let's use the correct word here) offended that some clown
> (again, correct word) claims engineering expertise and THEN grossly
missuses an
> extremely elemental engineering term. The guy was claiming expertise he
didn't
> have. Just like the diesel "expert" who tells you of the need to clean
the
> spark plugs on a diesel (Subastian Junger's mistake).
Chill out man! Somebody makes a mistake and you immediately call him a
fraud?
Albert Einstein saved himself with ordinary soap, because he couldn't tell
the difference between soap and shaving cream. Did that make him a lesser
than a brilliant scientist?
I really hate it when people start nagging about these kind of irrelevant
mistakes. I'm quite an experienced software engineer, but I still make
mistakes that make me want to bang my head agains my screen.
Meindert
Meindert Sprang
> counter-rotating props (supposedly) have no net torque to twist the
propulsion
> system. This can be a tremendous advantage in high-hp applications. The
> problem with counter-rotating props is that the second prop operates in
"dirty"
> air/water.
I'm NOT a prop specialist, but my gut feeling says that the aft prop
benefits from the counter-rotating water column from the first prop. The
energy in the rotating water pushed in a direction other than backwards. The
second prop 'deflects' this energy back in the right direction. Does that
make sense?
By the way, where is the air coming from in the 'dirty air/water'? In a
fully submerged prop I can only see vacuum bubbles appear fron cavitation.
Meindert
D MacPherson
I understand his point. I don't agree that it has any real significance to
the topic at hand, nor do I understand his seething hostility (I think I've
calmly addressed the important technical issues).
There is, indeed, a proper engineering/mathematical use of the term
"order" - as in "order of magnitude". When you say something is "of the nth
order" or "on the order of", it has a certain relational meaning. "On the
order of", however, is also a colloquial idiom used frequently in
conversation, and Roget's illustrates that it means "approximately" when
used in idiomatic context. It would be less than stellar in a peer-review
technical paper, but I don't think anyone missed my point when I used it to
describe a range of efficiency improvement - which was the point of the
post.
Every phrase we use has context. Even "efficiency" needs a modifier to
determine if we are discussing efficiency of propulsor, fuel rate, power
transmission. The content of one's remarks, however, can often by obscured
by using academic - albeit technically correct - nomenclature and
etymological structure. (The last sentence might even illustrate my point.)
So, for the most part, when I want to put down my thoughts "on paper", I
write like I speak...
Regards,
Don
Donald M. MacPherson
VP Technical Director
HydroComp, Inc.
email: d...@hydrocompinc.com
http://www.hydrocompinc.com
"Tom" <jaxa...@aol.com> wrote in message
news:b7Oh8.221$21h2.1...@news2.randori.com...
JAXAshby
>in engineering for the term "... on the order of..." ?
An "order of magnitude" is a power of ten. three orders of magnitude is 10^3.
Therefore, therefore"... on the order of 8% to 10% ..." makes no sense.
There is more to it, however. Three orders of magnitude (for instance)
actually (unless specifically stated as precise) means that something is
probably about 1,000 times greater, but there is a finite probability that it
is only about 100 times greater and a finite probability of it being 10,000
times greater. There is more to the nuance, but that's more or less it.
"An [meaning "one"] order of magnitude" means roughly probably greater than
twice and probably less than 100 times and most likely around 10 times.
Unless stated to be exactly "one order of magnitude", but this is slightly
misusing the term.
Anyone who has actually studied engineering -- or any of the hard sciences --
knew this before they had studied even a week at school.
JAXAshby
>fraud?
what would *you* call a poster who claims to be an expert in diesel engines but
doesn't know that diesels don't have spark plugs?
>I really hate it when people start nagging about these kind of irrelevant
>mistakes.
It's not hardly "irrelevant" in the world of engineering.
>I'm quite an experienced software engineer, but I still make
>mistakes that make me want to bang my head agains my screen.
And if someone tells you that CICS runs under MS-DOS what do *you* say?
>
>Meindert
JAXAshby
nor am I.
>...but my gut feeling says that the aft prop
>benefits from the counter-rotating water column from the first prop.
Lot's of drag issues there, I expect.
>...The
>energy in the rotating water pushed in a direction other than backwards. The
>second prop 'deflects' this energy back in the right direction. Does that
>make sense?
Doesn't intuitively to me, but maybe it does.
>
>By the way, where is the air coming from in the 'dirty air/water'?
I had referenced the Cessna 336/337 aircraft (planes with an engine infront of
the fuscelege and an engine in back. Said aircraft will fly higher and faster
with just the rear engine running than the front engine (same hp) because the
forward engine spins dirty air past the fuscelege)
>...In a
JAXAshby
>the topic at hand,
there is a significance in that engineers don't misused engineering terms in an
engineering discussion.
>nor do I understand his seething hostility
I dislike intensely internet frauds, and they abound.
Al
> >in engineering for the term "... on the order of..." ?
>
> An "order of magnitude" is a power of ten. three orders of magnitude is 10^3.
> Therefore, therefore"... on the order of 8% to 10% ..." makes no sense.
hmm... I'm in the education system right now (albeit not specifically
engineering) and we often describe mistakes as being on the order of x
out... Personally, I fail to see any difference in context between my
education system and this newsgroup. Anycase, surely this is way off
group... shouldn't you guys be discussing it by private email.
By the way, anyone with an engineering background should also have good
communication skills, I would describe D Macphersons communication
skills as exemplary in the context. You I fear may learn a little about
rationality in discussion from him... as well as the golden rule in
discussion or rational argument: Don't, whatever you do, p*** someone
off.
(yes, that is an informal rule)
Al
David
thread is, guess who, you. You're agruing with yourself, and loosing I might
add.
By the way there was a CICS (370 not 390) client that run under IBM PCDos in
the eighties......
"JAXAshby" <jaxa...@aol.com> wrote in message
news:20020307134543...@mb-md.aol.com...
D MacPherson
You're right about being off-topic. My apologies to the group. I had thought
about it a bit before sending my last post, and I felt there was enough
value in the discussion of technical communication to make it relevant.
My last words on this topic... (I'll gladly chime in, however, on anything
more suitable.)
Regards,
Don
Donald M. MacPherson
VP Technical Director
HydroComp, Inc.
email: d...@hydrocompinc.com
http://www.hydrocompinc.com
"Al" <Alm...@mygaff.fsnet.co.uk> wrote in message
news:3C87B9C0...@mygaff.fsnet.co.uk...
JAXAshby
>thread is, guess who, you. You're agruing with yourself, and loosing I might
>add.
It was a metaphor, Dave. Sorry that you didn't catch that.
>By the way there was a CICS (370 not 390) client that run under IBM PCDos in
>the eighties......
Are you being specious, Dave, or do you really not understand the difference
between CICS and CICS client. Also, do you not understand the difference
between MS-DOS and PCDos?
FWIW Dave, I believe you understand both and thus are not a fraud? Okay?
Dan Bollinger
> >mistakes.
>
I agree, chill out, Jax! Get a grip, this ain't an engineering forum! We
are here because we like to build boats, not argue about some esoteric
engineering definition. Guess what? We don't care! If you want to take Don
to task, then please, spare us all the diatribe and take it offline. Now,
back to building boats, please....
Dan
Dan Bollinger
as
> much in 4 years as every other institution teaches engineering students in
less
> than a week?
OUCH!
Dan Bollinger
>
I find Don to be the real McCoy. A couple of years ago he was kind enought
to copy and mail to me a unique, very old and very important German article
on paddlewheel propulsion efficiencies. I seriously doubt that a fraud
would have the knowledge or resources to obtain that document.
Just so you know, Jax, you are one post away from being kill-filed by me
because of your rudeness. Dan
Stephen Baker
Now I know why I killfiled Jax a while ago.
Doug
jaxa...@aol.com (JAXAshby) wrote in message news:<20020307101358...@mb-mq.aol.com>...
> Dan, I'm not debating the paddlewheel vs prop. I just don't know very much
> about the subject, and candidly, find it only an interesting item for a moment.
> However, I am (let's use the correct word here) offended that some clown
> (again, correct word) claims engineering expertise and THEN grossly missuses an
> extremely elemental engineering term. The guy was claiming expertise he didn't
> have. Just like the diesel "expert" who tells you of the need to clean the
> spark plugs on a diesel (Subastian Junger's mistake).
>
> I come here to learn and am offended by frauds, engineering or otherwise.
>
> >"JAXAshby" <jaxa...@aol.com> wrote in message
> >news:20020307093555...@mb-cu.aol.com...
> >> donny, "graduating" from some place that advertises on the backs of
> matchbook
> >> covers does not make you an engineer.
> >>
> >> Kriste almighty man! You used an extremely elemental term incorrectly.
> You
> >> expect *anyone* to believe you know what you're talking about?
> >>
> >> Let's say you come to this board claiming to be an expert in diesel
> engines but
> >> then tell us how to check the spark plugs. Would anybody believe you know
> >> diddly about diesels?
> >>
> >> So, why you want us to believe that any engineer doesn't know what "on the
> >> order of" means? (hint, to an engineer when discussing an engineering
> subject
> >> ain't no way in hell it means "about")
Jaxashby
http://www.bareboating.com/sailing/oregon_sailing.jpg
"Stephen Baker" <saild...@aol.comnospam> wrote in message
news:20020307145421...@mb-mq.aol.com...
Pat Ford
The strange parade of JAXAshby on USENET has continued for some time
now. We've seen his arrogant attacks, counterattacks, pictures of
JAXAshby in his underwear, and his denunciations of his former
girlfriend. All of which were a waste of bandwidth.
At first he was infuriating, then strange. Now his continuing rages
are just pathetic. He needs help which will not be found in the
confines of this newsgroup.
Please don't feed the troll.
And I'll obey my advice in the future
Matt Colie
Maybe you would do well to look again. Webb is one of those school that
only industy people care about. I got two on my bachelors from Ft.
Schuyler and nobody out here is this flat land understands until I them
about the ME from U of Mich (which hasn't been much value except to
impress HR people).
Matt Colie A.Sloop "Bonne Ide'e" S2-7.9 #1
Lifelong Waterman, Licensed Mariner and Perpetual Sailor (With Sheepskin
on the wall)
JAXAshby wrote:
> donny, "graduating" from some place that advertises on the backs of matchbook
> covers does not make you an engineer.
>
> Kriste almighty man! You used an extremely elemental term incorrectly. You
> expect *anyone* to believe you know what you're talking about?
>
> Let's say you come to this board claiming to be an expert in diesel engines but
> then tell us how to check the spark plugs. Would anybody believe you know
> diddly about diesels?
>
> So, why you want us to believe that any engineer doesn't know what "on the
> order of" means? (hint, to an engineer when discussing an engineering subject
> ain't no way in hell it means "about")
>
>
>>8. Hadler, J.B., Morgan, W.B., and Meyers, K.A., "Advanced-Propeller
>>Propulsion for High-Powered Single-Screw Ships", SNAME Transactions, 1964
>>
>>Regards,
>>
>>Don
>>
>>Donald M. MacPherson
>>VP Technical Director
>>HydroComp, Inc.
>>email: d...@hydrocompinc.com
>>http://www.hydrocompinc.com
>>
>>
Meindert Sprang
> > And exactly what is the specific mathematical meaning that is
important
> >in engineering for the term "... on the order of..." ?
>
> An "order of magnitude" is a power of ten. three orders of magnitude is
10^3.
> Therefore, therefore"... on the order of 8% to 10% ..." makes no sense.
With all due respect, this is utter bullsh*t. As you just said yourself,
with an 'order of magnitude' it is a power of ten indeed. But just 'on the
order of' without the word magnitude, means just like 'in the range of' or
something similar.
Meindert
Meindert Sprang
news:08Qh8.232$21h2.1...@news2.randori.com...
> Ok, losers, heres why I always have to be right
>
> http://www.bareboating.com/sailing/oregon_sailing.jpg
>
Huh? If I post a link to my favourite pink fluffy elephant, would always be
right too?
Meindert
JAXAshby
boat Mike Plant was killed on when its keel fell off.
btw, Mike was a high school friend of my sister.
JAXAshby
I am not so glad that Don claimed to be an engineer and then grossly misused a
term fully understood by every engineer.
JAXAshby
JAXAshby
on the order of 8% to 10%" any more than any diesel designer talks of spark
plugs in a diesel. It's just not done by engineers, at least not in an
engineering discussion. It is done, however, by those who wish to sound like
engineers but don't really undestand even the basic lingo. Okay?
Dazed and Confuzed
man. Deal with it. Quit making excuses and trying to deflect things onto others.
Admit it. Learn from it. Go forward.
JAXAshby wrote:
--
"They that can give up liberty for safety deserve neither liberty nor
safety." Benjamin Franklin
Mark Eckerberg
turbine.
I've been trying to come up with a good way to configure a shunting
proa motorsailer that could motorsail in either direction. Something
like this would work but it is what I refer to as a contraption. It
is a fairly complicated thing that would have to be custom built. (i
assume, in the range of 10 to 20 hp)
On a multihull it could be under the wing so that all the rotating
pieces don't need to be sealed. I wander how it would work if the
blades were "surface piercing" like a sculling oar. I suppose it
would cavitate.
-Mark
On Wed, 06 Mar 2002 13:45:35 GMT, "Dan Bollinger"
<danbol...@insightbb.com> wrote:
>> It is a cycloidal propeller, commonly know as a Voith-Schneider drive
>> after the German company that bought the patent from Frederick Kirsten
>> and developed the concept to what it is today.
>>
>> Rick
>
>Exactly. Here is the website, check out the animation, too.
>http://www.voith-schiffstechnik.com/shared/set_main.htm
>
>
>
Ma...@home.net
>benefits from the counter-rotating water column from the first prop. The
>energy in the rotating water pushed in a direction other than backwards. The
>second prop 'deflects' this energy back in the right direction. Does that
>make sense?
>
with its internal vanes.
-Mark
Stephen Baker
news:08Qh8.232$21h2.1...@news2.randori.com...
> Ok, losers, heres why I always have to be right
>
> http://www.bareboating.com/sailing/oregon_sailing.jpg
>
OK, I know this isn't professional, but I have to ask.
Why does having a teeny weeny make you have to be right?
Stephen Baker
>with an 'order of magnitude' it is a power of ten indeed. But just 'on the
>order of' without the word magnitude, means just like 'in the range of' or
>something similar.
>
>Meindert
Pre-zactly! (to coin a word)
JAXAshby
that you are gay. None whatsoever.
Dan Bollinger
<Ma...@home.net> wrote in message news:3c88784b...@news.verizon.net...
I believe so, too. Steam turbines have a series of rotors/stator
combinations. Without the stators the turbines would be less efficient.
Dan Bollinger
"Mark Eckerberg" <bo...@whydoineedthistomakeitsend.why> wrote in message
news:3c887395...@news.verizon.net...
> That is cool. Thanks for the help. It reminds me of a darius wind
> turbine.
Similar, but I don't think the Darius has feathering foils.
> I've been trying to come up with a good way to configure a shunting
> proa motorsailer that could motorsail in either direction. Something
> like this would work but it is what I refer to as a contraption. It
> is a fairly complicated thing that would have to be custom built. (i
> assume, in the range of 10 to 20 hp)
Yes, quite a contraption! I wouldn't worry about surface piercing problems.
It is a minimal loss, no more than the drag on a skeg to hold a prop.
Cavitation won't be a problem since the large area blades turn relatively
slowly. Your biggest problem will be in designing a way of retracting the
whole shebang while sailing.
Craig Kossowski
> fitted with feathering sidewheels and curved blades around 1890. Besides
> efficiencies of 80% they are the only water drive that has less draft than
> the boat.
While obviously not _typically_ designed this way, it's perfectly possible
to design a waterjet with this property.
Craig K.
Jean Daugherty
drivel when people respond to him. Even that minimized rate of exposure
spoils some otherwise very interesting discussions for me. I doubt he has
many fans, so he must thrive on being shown a fool. Could we stop feeding
his disease?
"Dan Bollinger" <danbol...@insightbb.com> wrote in message
news:6nPh8.19$uA5...@rwcrnsc51.ops.asp.att.net...
JAXAshby
>combinations. Without the stators the turbines would be less efficient.
I understood the stators were there to redirect the steam to an efficient angle
to meet the rotor blades. Could be wrong.
For sure, the stator blades on a jet engine compressor are there to slow down
the air movement to compress it.
JAXAshby
Good for him.
Dan Bollinger
> to design a waterjet with this property.
>
> Craig K.
>
I don't know how. Any inlet on the bottom will require a minimum of 6"
(realistically more like 12") of water below the keel to prevent sand,
seaweeds and gravel from being injested. This means that a jet drive's true
draft is 6" plus the depth of the boat itself. A paddlewheeler is always
less than the draft of the boat it propels. Unless you know something I
don't...
Stephen Baker
>less than the draft of the boat it propels. Unless you know something I
>don't...
Of course, there is the so-called "canal effect" where the suction of a
vessel's motion will pull it down and ground it if the water is too shallow
beneath the keel. So even a paddle-wheeler (especially flat-bottomed) needs a
bit more draft than the hull.
Steve
Craig Kossowski
> I don't know how. Any inlet on the bottom will require a minimum of 6"
> (realistically more like 12") of water below the keel to prevent sand,
> seaweeds and gravel from being injested. This means that a jet drive's true
> draft is 6" plus the depth of the boat itself. A paddlewheeler is always
> less than the draft of the boat it propels. Unless you know something I
> don't...
In the same way that an F-15 differs from an F-16, put the intake scoops
on the sides of the hull instead of underneath. Of course, this raises
it's own disadvantages (surface ventilation, on boats which are already
low draft, additional complexity, likely additional drag), so it's not
preferable exept if you want extremely low draft jet drive. Some FOD
protection is going to be necessary in such an implimentation anyhow.
Craig K.