Re: [bolger] Powering the Snow Goose
In a message dated 5/15/00 1:27:36 PM Central Daylight Time,
smuller@...writes:
<< The general consensus among today's designers and builders seem to
be, the formulas for things like slippage, size, ratio of width to
diameter, etc. no longer exist, and they question if they ever did,
exist. >>
Thanks for the feed-back and web-site info for further research. I'm very
skeptical that the designers of paddle-wheel vessels in their heyday did not
have empirical formulas that they relied on. The designers, or at least many
of them, must have been highly competent engineers for their era, who were
entrusted with making good judgements on matters that required large capital
investments (think of Brunel, Eads, et al.) I think they had more
sophisticated analytical tools than simple guesswork. Where one could learn
about their methods (assuming I'm correct), I do not know. I'm perusing a
copy of "Lindsay's Technical Books Catalog" at the moment. The publisher
offers a 685 page manual "Modern Locomotive Construction", copyright 1892!,
an 1896 treatise on Steam Engine Design, and other historical curiosities,
but no "Modern" steamboat construction manual, alas.
I only mentioned "Stronger Than A Hundred Men" as it is the only book I own
that I could conceivably try to use as reference material. Its an interesting
book, but I'm not sure of any practical application to the design of
paddewheels.
Bill in MN
smuller@...writes:
<< The general consensus among today's designers and builders seem to
be, the formulas for things like slippage, size, ratio of width to
diameter, etc. no longer exist, and they question if they ever did,
exist. >>
Thanks for the feed-back and web-site info for further research. I'm very
skeptical that the designers of paddle-wheel vessels in their heyday did not
have empirical formulas that they relied on. The designers, or at least many
of them, must have been highly competent engineers for their era, who were
entrusted with making good judgements on matters that required large capital
investments (think of Brunel, Eads, et al.) I think they had more
sophisticated analytical tools than simple guesswork. Where one could learn
about their methods (assuming I'm correct), I do not know. I'm perusing a
copy of "Lindsay's Technical Books Catalog" at the moment. The publisher
offers a 685 page manual "Modern Locomotive Construction", copyright 1892!,
an 1896 treatise on Steam Engine Design, and other historical curiosities,
but no "Modern" steamboat construction manual, alas.
I only mentioned "Stronger Than A Hundred Men" as it is the only book I own
that I could conceivably try to use as reference material. Its an interesting
book, but I'm not sure of any practical application to the design of
paddewheels.
Bill in MN
Bill in MN,
You Sir, are a prince among men! In answer to your, "Did
you find any useful info on this topic on the "net"? ", question, I must
say, up until your posting, not really. In point of fact, the following
is a quote from the American Stern Wheeler Assoc.
"Wheel Size and Design;
There is no consensus on the proper wheel size. Some argue for the
biggest wheel possible, while others use smaller wheels rather than
additional gearing. Some prefer deep dip for more force, others believe
in letting the wheel rev up. Neither races or shoving contests prove one
idea to be clearly better than another."
((see));http://www.coe.wvu.edu/~venable/asa/asa-home.htm
The general consensus among today's designers and builders seem to
be, the formulas for things like slippage, size, ratio of width to
diameter, etc. no longer exist, and they question if they ever did,
exist. There are, however, some rules of thumb that are used today. For
instance; the number of buckets (paddles) should be the diameter in
feet, plus two. Another is; the diameter should not exceed the width.
((see));http://www.wirefire.com/gemort/harbor/Wheel.htm
Your, "very crude number crunching" is right on the money. The
numbers I used, were just off the top of my head, a more accurate RPM
would be closer to 100, using a 33% efficiency factor to include things
like slippage etc.. and that, is still only a guess.
In order to overcome so many unknowns, my plan is, once the unit is
built, I intend to mount it on our picnic table, back it up to our fish
pond, and with a bathroom scale to measure thrust (or push) trim and
adjust dip etc. for the highest numbers. Just think, I'll be the only
kid on the block with my very own paddle wheel dynamometer. ;-)
I called our local library today and ordered a copy of, "Stronger
Than A Hundred Men", but I won't know for a few days if they can get it
for me, so wish me luck. I recently heard about a web site about a CSA
blockade runner with feathering floats, that I'll have to look into.
Lets face it, floats made out of feathers would have to be light weight,
and would break the cycle of having to add more weight up forward
leading to the ultimate renaming of the Snow Goose to Platypus. ;-)
One last quote, from the American Stern Wheeler Assoc.; Under
"Reasons for survival, The most important reason that the paddlewheel
boats has survived this long is nostalgia. There are other reasons to be
sure, but nostalgia reigns supreme."
Best regards, Stan, of the Stern Wheeled Micro Tugger, Snow Goose.
You Sir, are a prince among men! In answer to your, "Did
you find any useful info on this topic on the "net"? ", question, I must
say, up until your posting, not really. In point of fact, the following
is a quote from the American Stern Wheeler Assoc.
"Wheel Size and Design;
There is no consensus on the proper wheel size. Some argue for the
biggest wheel possible, while others use smaller wheels rather than
additional gearing. Some prefer deep dip for more force, others believe
in letting the wheel rev up. Neither races or shoving contests prove one
idea to be clearly better than another."
((see));http://www.coe.wvu.edu/~venable/asa/asa-home.htm
The general consensus among today's designers and builders seem to
be, the formulas for things like slippage, size, ratio of width to
diameter, etc. no longer exist, and they question if they ever did,
exist. There are, however, some rules of thumb that are used today. For
instance; the number of buckets (paddles) should be the diameter in
feet, plus two. Another is; the diameter should not exceed the width.
((see));http://www.wirefire.com/gemort/harbor/Wheel.htm
Your, "very crude number crunching" is right on the money. The
numbers I used, were just off the top of my head, a more accurate RPM
would be closer to 100, using a 33% efficiency factor to include things
like slippage etc.. and that, is still only a guess.
In order to overcome so many unknowns, my plan is, once the unit is
built, I intend to mount it on our picnic table, back it up to our fish
pond, and with a bathroom scale to measure thrust (or push) trim and
adjust dip etc. for the highest numbers. Just think, I'll be the only
kid on the block with my very own paddle wheel dynamometer. ;-)
I called our local library today and ordered a copy of, "Stronger
Than A Hundred Men", but I won't know for a few days if they can get it
for me, so wish me luck. I recently heard about a web site about a CSA
blockade runner with feathering floats, that I'll have to look into.
Lets face it, floats made out of feathers would have to be light weight,
and would break the cycle of having to add more weight up forward
leading to the ultimate renaming of the Snow Goose to Platypus. ;-)
One last quote, from the American Stern Wheeler Assoc.; Under
"Reasons for survival, The most important reason that the paddlewheel
boats has survived this long is nostalgia. There are other reasons to be
sure, but nostalgia reigns supreme."
Best regards, Stan, of the Stern Wheeled Micro Tugger, Snow Goose.
In a message dated 5/13/00 12:53:08 PM Central Daylight Time,
smuller@...writes:
<< The wheel, as designed, so far, is to be approximately four feet in
diameter, have six blades, and be four feet wide. >>
Stan: Very crude number crunching (i.e. (4' diameter X (22/7) x 30 RPM X 60
Min./Hr.)/ 5280 Ft./Mile) suggests a top speed with zero slip (an
unattainable and not even desirable goal, per Dr. David Gerr of the
"Propeller Handbook") of roughly 4.2 MPH. Mind you, the above calculation
represents the entire sum of my notions about the subject and I do not
advance it as more than uninformed speculation. Still, me thinks that you may
need greater diameter and/or higher RPM to achieve your speed objective. Did
you find any useful info on this topic on the "net"?
How did you arrive at your decision on the number of paddles? I know that
during the late 18th and early 19th centuries there was some controversy
among savants as to the desirable number of floats an under-shot water wheel
should have for maximum efficiency. I believe this was resolved on an
empirical basis by Smeeton, builder of the Eddystone Lighthouse among other
accomplishments, as basically the more "floats" (or "paddles") the merrier as
far as efficiency goes. I would guess that putting power into a stern paddle
wheel and extracting power from a simple under-shot water wheel would be
equivalent functions, as far as energy use/production is concerned.
I recall seeing a description of some small stern wheeler's purpose-designed
for use on small rivers in southeast Asia for Her Majesty, Queen Victoria's
navy. They had two stern paddlewheels, side-by-side, to enhance
manueverability! Now with two golf cart engines and transmissions, you might
be able to dispense with rudders altogether!
Anyway, I'm looking forward to seeing pictures of you creation.
Ciao for Niao,
Bill in MN
smuller@...writes:
<< The wheel, as designed, so far, is to be approximately four feet in
diameter, have six blades, and be four feet wide. >>
Stan: Very crude number crunching (i.e. (4' diameter X (22/7) x 30 RPM X 60
Min./Hr.)/ 5280 Ft./Mile) suggests a top speed with zero slip (an
unattainable and not even desirable goal, per Dr. David Gerr of the
"Propeller Handbook") of roughly 4.2 MPH. Mind you, the above calculation
represents the entire sum of my notions about the subject and I do not
advance it as more than uninformed speculation. Still, me thinks that you may
need greater diameter and/or higher RPM to achieve your speed objective. Did
you find any useful info on this topic on the "net"?
How did you arrive at your decision on the number of paddles? I know that
during the late 18th and early 19th centuries there was some controversy
among savants as to the desirable number of floats an under-shot water wheel
should have for maximum efficiency. I believe this was resolved on an
empirical basis by Smeeton, builder of the Eddystone Lighthouse among other
accomplishments, as basically the more "floats" (or "paddles") the merrier as
far as efficiency goes. I would guess that putting power into a stern paddle
wheel and extracting power from a simple under-shot water wheel would be
equivalent functions, as far as energy use/production is concerned.
I recall seeing a description of some small stern wheeler's purpose-designed
for use on small rivers in southeast Asia for Her Majesty, Queen Victoria's
navy. They had two stern paddlewheels, side-by-side, to enhance
manueverability! Now with two golf cart engines and transmissions, you might
be able to dispense with rudders altogether!
Anyway, I'm looking forward to seeing pictures of you creation.
Ciao for Niao,
Bill in MN
Hi Ron, Thanks for your bow rudder idea. This is certainly worth looking
into and it would add nicely to the otherwise restricted steering
inherent to a stern wheeler.
Hi Peter, Yes, I asked for it, and I thank you for your comments. ;-)
First, I must admit, much of my reasoning toward going stern wheel, is
purely for the fun of it. Beyond that are reasons of cost, using
something I have, as opposed to something I must buy, and then there is
the ability of, "do it yourself repair". I find it easier to repair a
single cylinder four stroke, than the run of the mill outboard. Part of
my thinking here is, I have about 400 miles of Missouri river with few
to no marinas, but many small towns with lawnmower shops. While we are
on the subject of the river, where the normal current speed is 4 to 5
knots, and a Micro whose hull speed is 4.5 knots, the only way to go
upstream is to make use of back currents and eddies in the shallows.
Thus the need for ultra shoal draft, and the problem with propellers
hanging down. A friend and I did some canoeing in the river, and as I
said, going up stream is to say the least, tricky, but it can be done.
As to the ballast and trim problem; I have withheld mounting the keel
ballast until I can float her and see what I am up against because of my
changes. At that time I also plan to alter (lessen) the weight of the
ballast in order to achieve the original water line with all the major
equipment on board. The pilot house added less than one hundred pounds,
including windows and all. The placement of the weight of the paddle
wheel, out beyond the stern, is to say the least going to be a
challenge, but with enough forethought, I think I can keep the weight
down to the point that by moving my two deep cycle batteries forward, I
can balance it out. I did, however, get a kick out of the concept of
the Micro-Sub, Platypus
Thanks for the thoughts, it always helps to see things from the
perspective of others.
All the best, Stan Micro Tugger, Snow Goose.
into and it would add nicely to the otherwise restricted steering
inherent to a stern wheeler.
Hi Peter, Yes, I asked for it, and I thank you for your comments. ;-)
First, I must admit, much of my reasoning toward going stern wheel, is
purely for the fun of it. Beyond that are reasons of cost, using
something I have, as opposed to something I must buy, and then there is
the ability of, "do it yourself repair". I find it easier to repair a
single cylinder four stroke, than the run of the mill outboard. Part of
my thinking here is, I have about 400 miles of Missouri river with few
to no marinas, but many small towns with lawnmower shops. While we are
on the subject of the river, where the normal current speed is 4 to 5
knots, and a Micro whose hull speed is 4.5 knots, the only way to go
upstream is to make use of back currents and eddies in the shallows.
Thus the need for ultra shoal draft, and the problem with propellers
hanging down. A friend and I did some canoeing in the river, and as I
said, going up stream is to say the least, tricky, but it can be done.
As to the ballast and trim problem; I have withheld mounting the keel
ballast until I can float her and see what I am up against because of my
changes. At that time I also plan to alter (lessen) the weight of the
ballast in order to achieve the original water line with all the major
equipment on board. The pilot house added less than one hundred pounds,
including windows and all. The placement of the weight of the paddle
wheel, out beyond the stern, is to say the least going to be a
challenge, but with enough forethought, I think I can keep the weight
down to the point that by moving my two deep cycle batteries forward, I
can balance it out. I did, however, get a kick out of the concept of
the Micro-Sub, Platypus
Thanks for the thoughts, it always helps to see things from the
perspective of others.
All the best, Stan Micro Tugger, Snow Goose.
>From: Stan Muller <smuller@...>Hi Stan,
> than enough torque. The only major redesign will be the steering.
> From the information I have been able to glean from the web, the
> normal setup is to have four rudders, two in front of the wheel and
> two aft of the wheel. This will call for some empirical engineering
> when the time comes.
Four rudders!!?? Wow. This looks like it could be a good
reason to try out a bow rudder. I know PCB has done some
"testing" with bow rudders, maybe he could be of some help with
the size and location.
Ron