HULL SPEED DEF.
Bobsprit
trying to explain it to someone last week and by the time I was done I had
confused myself!!!
So....tell me like a 2 year old....explain Theoretical Hull Speed, so I can
relay to my friend. Doug, Marty?
Thanks,
Robert B
GHOST-Pearson 30
City Island, NY
Douglas S. King
> Can someone explain the physics of Hull Speed in VERY SIMPLE terms. I was
> trying to explain it to someone last week and by the time I was done I had
> confused myself!!!
> So....tell me like a 2 year old....explain Theoretical Hull Speed, so I can
> relay to my friend.
OK, here goes: start with the definition of a boat: a hole in the water into
which you pour money. Forget the money part for now.
When the boat moves, it has to shove water out of it's way. When the boat is
past, the water has to slosh back into place behind it. Water is heavy, and it
doesn't like to move quickly.
So both in front and behind, water is being shoved one way and then yanked
back again. That makes waves. The faster the boat goes, the bigger the bow
wave gets because the boat is pushing the water harder and harder. The stern
wave gets bigger too, but that's a bit more difficult to explain without going
into fluid mechanics. The basic principle is that water pushes against other
bits of water, this is how ripples spread when you drop a rock into a pond.
Simple explanation- As the bow wave gets bigger the boat is effectively going
uphill, and the steeper the hill gets the more power the boat needs. At some
point, it reaches the limit of available power and that is hull speed.
A little more complicated- the waves have to travel at the same speed as the
boat, and the length between the tops of the waves determine how fast the wave
can go. This is because water is not only heavy but has viscosity (water
molecules are sticky- sounds funny but it's true if you think about it,
otherwise we wouldn't need towels) and there is a limit to how fast it can go
up and down to form waves. A longer boat can have it's bow and stern waves
further apart, and thus has a higher hull speed.
I don't expect a Nobel Prize for this explanation but it should cover the
bases.
For bonus points does anyone want to explain planing?
Fresh Breezes- Doug King
--
This is what we look like when we're at our best:
http://recboats.hsh.com/45.htm
Ching and Bob Walters
As a boat moves through water it makes waves. At low speeds you will notice
a series of crests and troughs along the side of the boat.
As the speed of the boat increases, it eventually reaches a speed so that
you will notice only a single crest at the bow, another crest at the stern,
with a single trough amidships.
This "single wave" speed is dependant on the waterline length and is
generally taken to be (in knots) 1.34 times the square root of the waterline
length. It is commonly called the "hull speed".
In order to go faster than this "hull speed", the boat will have to sail or
motor "uphill" to climb the bow wave. The boat has to climb up out of the
hole in the water it makes.
Now the size of the bow and stern crests and the depth of the trough is
highly dependant on the displacement of the boat, the hull shape, and how
that displacement is distributed. It follows that the power required to
climb this bow wave is also dependant on the size of the bow wave. The
power required can be huge if the bow wave is huge and vice-versa.
Picture a tug boat at speed. These short, fat, heavy, but very powerful
boats produce a huge wave (and wake) at speed, but in spite of having
thousands of horsepower, they can't climb their large bow wave and exceed
their "hull speed". They are also hampered by their stern sections, which
generally curve upwards to provide smooth water flow at low speeds rather
than promote lift, as might be done on a boat designed to plane.
On the other hand, there are light, powerful, planing boats which "sit light
on the water" and can easily climb their small bow wave and exceed their
hull speed and transition into the planing mode. Boats plane more easily if
they are light, powerful, and have flat stern sections which produce lift at
the expense of increased drag at low speeds. Remember, everything is a
compromise.
In between pure displacement boats and high speed boats designed to plane
most of the time, there are boats that can exceed their "theoretical hull
speed" under certain conditions. This seems to confuse a lot of people who
post here, but it's pretty simple.
A boat that's not too heavy and has somewhat flat stern sections and more
than minimal power, and one that is perhaps a bit "skinnier" than average
can go faster than 1.34 times the square root of the waterline length. If
it climbs only part way up it's bow wave it is usually called "semi
planing". Obviously the smaller the bow wave, the easier it is to do this.
Really long, skinny, light craft (like multihulls or ULDB boats) can be
expected to move at speeds significantly higher than 1.34 times the square
root of the waterline length. In other words, 1.34 (often called the speed
to length ratio) is not a fixed number. That shouldn't surprise anyone, but
apparently it confuses some who post in this NG.
Does this help?
Bob Walters
PERDIDO DESIGN
check out the web page at:
http://perdidodesign.home.att.net
Bobsprit wrote in message <20000719073253...@ng-fk1.aol.com>...
>Can someone explain the physics of Hull Speed in VERY SIMPLE terms. I was
>trying to explain it to someone last week and by the time I was done I had
>confused myself!!!
>So....tell me like a 2 year old....explain Theoretical Hull Speed, so I can
Randy Walton
posting.
"Ching and Bob Walters" <boban...@worldnet.att.net> wrote in message
news:Dwhd5.6625$o71.3...@bgtnsc04-news.ops.worldnet.att.net...
Mark Weaver
"Ching and Bob Walters" <boban...@worldnet.att.net> wrote in message
news:Dwhd5.6625$o71.3...@bgtnsc04-news.ops.worldnet.att.net...
> Sure.......here goes.
>
>
> most of the time, there are boats that can exceed their "theoretical hull
> speed" under certain conditions. This seems to confuse a lot of people
who
> post here, but it's pretty simple.
>
> A boat that's not too heavy and has somewhat flat stern sections and more
> than minimal power, and one that is perhaps a bit "skinnier" than average
> can go faster than 1.34 times the square root of the waterline length. If
> it climbs only part way up it's bow wave it is usually called "semi
> planing". Obviously the smaller the bow wave, the easier it is to do
this.
>
> Really long, skinny, light craft (like multihulls or ULDB boats) can be
> expected to move at speeds significantly higher than 1.34 times the square
> root of the waterline length. In other words, 1.34 (often called the speed
> to length ratio) is not a fixed number. That shouldn't surprise anyone,
but
> apparently it confuses some who post in this NG.
>
One thing to add. A Dave Gerr (marine architect and author of "The Nature
of Boats") has worked out a formula which in intended to capture the effect
of displacement on the 1.34 constant. A web site that implements Gerr's
formula can be found here:
http://www.yachts4sail.com/hullspeed.html
It's pretty interesting to play with some numbers and see the effect of a
heavy load on the hull speed of your own boat as well as the differences in
hull speed between, say, a 25-footer (LWL of 22') displacing 3000# (8.6
knots) vs a 25-footer displacing 6000# (6.9 knots). Of course, whether your
sailplan has enough power to push your boat to those hull speeds is another
matter...
Mark
Gilligan
viscous it cannot be pushed out of the way instantly. Hence the water
stacks up and forms a wave, just like dirt in front of a bulldozer
blade. The energy used in creating a wave is mostly work against
gravity - the lifting up of water. The faster a boat goes the more
water it stacks up, until the weight of the water lifted is roughly
equal to the displacement of the boat. In some boats this occurs at
lower speeds (Pearson 30) and with other well designed boats it occurs
at higher speeds(Coronado 27 when excellently skippered). To go at
higher speeds the weight of the water lifted exceeds the weight of the
boat. This lifted water puts a bouyant force on the boat and pushes it
up on plane.
There are subtle design influences that can increase the "theoretical"
hull speed of the boat. All of these are incorporated into the Coronado
27. Firstly a close examination of the waves from the bow and stern of
the swift Coronado 27 will show that they are in phase quadrature. This
means that the energy in the hull wave remains in the vicinity of the
hull, helping to propel it along rather than the energy travelling away
from the hull. This is very important.
Secondly, the choice of hull color is a big factor. The ocean, being a
blue-green color has a natural repulsion to the color yellow. Yellow
hulls eliminate the natural optical adhesion of ocean water. They are
almost frictionless. White hulls, on the other hand, in their color are
slowed by the interaction with the virtual photons emitted/absorbed by
the water.
A third factor is the hull shape. To create turbulence is to disappate
energy and to move slowly. All the fast creatures of the sea -
dolphins, whales, and even submarines have a shape in distinct
proportion - the same proportions of the Coronado 27. Notice how
silently the Coronado 27 slips through the water.
In fact, the reason that there are so few Coronado 27's to be bought is
a matter of national security. The Dept. Of Defense did not want the
hull design secrets of this unnaturally swift vessel to fall into
hostile hands. So most of the existing Coronado 27s were destroyed in
the interest of national security. The good Capt. Neal, a holder of top
secret security clearance, is more than qualified to own a Coronado 27.
His excellent and exceptional seamanship skills would guarantee that
this craft would never fall into enemy hands.
I think the good Capt. Neal was being very conservative and modest in
his assessment of the hull speed of his boat. I'm certain that his
innate compassion drove him to underestimate its performance so as not
to offend owners of all other (slower) boats.
Gilligan
* Sent from RemarQ http://www.remarq.com The Internet's Discussion Network *
The fastest and easiest way to search and participate in Usenet - Free!
Rich Hampel
Heres another simplistic explaination ..... for a 'displacement' hull ......
A displacment hull makes 2 principal waves: one at the bow and one at the stern.
At speeds **less than or equal to hull speed** the bow wave will be under the bow and the stern wave
will be under the stern or in front of the stern ... both waves will support the boat equally - the
boat will be ******level**.
At speeds **greater than hull speed**, (due to wave formation) the bow wave will be under the bow
and the stern wave will start to separate from the stern, move behind the stern, no longer support
the hull .... and leave a big 'hole' in the water (trough) - under the stern. Since the boat is no
longer equally supported, the bow will start to rise or lift; and, the stern will start to sink -
thus making the boat 'unlevel' and in an attitude that makes it attempt to climb the 'hill (slope)
of water' under the hull.
At speeds **much greater than hull speed** the bow wave will move behind the bow, the front of the
bow will be in front of the bow wave (sometimes completely out of the water) ----- thus decreasing
waterline length. The stern (not supportred by the bow wave, will begin to seek the lowest part of
the trough between the two waves: severe 'bow-up' . Result: Decreased waterline length, and
trying to go uphill !!!!
Drum roll ....... So hull speed is the very fastest a displacement hull boat can go and still be LEVEL.
Incidentally, you can determine the exact constant (varies from 1 to 1.5 ...and not always 1.34) for
your specific hull form by simply measuring when the boat starts to deviate appreciably from being
level while at ever increasing speed. (of course you have to measure the **exact** waterline length
and not the static water line length to arrive at a correct answer).
Another way to get your hull speed is to plot increasing speed (motor driven) versus rpm. As you
start from zero speed versus zero rpm (speed vs. rpm) you will notice that the plot of the data
points start out as essentially a straight line. During this process of increasing speed there will
a point on your graph where the increased rpm does not generate a proportional amount of increased
speed. Guess what? - you just discovered YOUR hull speed. If you plot the points carefully you
will get a 'knuckle' where the straight line changes to another straight line at a different angle.
The transition between the two straight line portions of the plot is the 'hull speed".
Look over the side at this point and see the stern wave beginning to separate and no longer
supporting the hull, the bow rises and the stern starts to sink.
Large stink-potters usually have this plot onboard and religiously set the max. cruising rpm to
obtain max speed versus max economy (fuel consumption).
:-)
Bill Bannon
Neal's explanation of why you are wrong.
Bill Bannon
Ching and Bob Walters wrote:
>
> Sure.......here goes.
>
> As a boat moves through water it makes waves. At low speeds you will notice
> a series of crests and troughs along the side of the boat.
>
> As the speed of the boat increases, it eventually reaches a speed so that
> you will notice only a single crest at the bow, another crest at the stern,
> with a single trough amidships.
>
> This "single wave" speed is dependant on the waterline length and is
> generally taken to be (in knots) 1.34 times the square root of the waterline
> length. It is commonly called the "hull speed".
>
> In order to go faster than this "hull speed", the boat will have to sail or
> motor "uphill" to climb the bow wave. The boat has to climb up out of the
> hole in the water it makes.
>
> Now the size of the bow and stern crests and the depth of the trough is
> highly dependant on the displacement of the boat, the hull shape, and how
> that displacement is distributed. It follows that the power required to
> climb this bow wave is also dependant on the size of the bow wave. The
> power required can be huge if the bow wave is huge and vice-versa.
>
> Picture a tug boat at speed. These short, fat, heavy, but very powerful
> boats produce a huge wave (and wake) at speed, but in spite of having
> thousands of horsepower, they can't climb their large bow wave and exceed
> their "hull speed". They are also hampered by their stern sections, which
> generally curve upwards to provide smooth water flow at low speeds rather
> than promote lift, as might be done on a boat designed to plane.
>
> On the other hand, there are light, powerful, planing boats which "sit light
> on the water" and can easily climb their small bow wave and exceed their
> hull speed and transition into the planing mode. Boats plane more easily if
> they are light, powerful, and have flat stern sections which produce lift at
> the expense of increased drag at low speeds. Remember, everything is a
> compromise.
>
> In between pure displacement boats and high speed boats designed to plane
> most of the time, there are boats that can exceed their "theoretical hull
> speed" under certain conditions. This seems to confuse a lot of people who
> post here, but it's pretty simple.
>
> A boat that's not too heavy and has somewhat flat stern sections and more
> than minimal power, and one that is perhaps a bit "skinnier" than average
> can go faster than 1.34 times the square root of the waterline length. If
> it climbs only part way up it's bow wave it is usually called "semi
> planing". Obviously the smaller the bow wave, the easier it is to do this.
>
> Really long, skinny, light craft (like multihulls or ULDB boats) can be
> expected to move at speeds significantly higher than 1.34 times the square
> root of the waterline length. In other words, 1.34 (often called the speed
> to length ratio) is not a fixed number. That shouldn't surprise anyone, but
> apparently it confuses some who post in this NG.
>
> Does this help?
>
> Bob Walters
> PERDIDO DESIGN
> check out the web page at:
> http://perdidodesign.home.att.net
>
> Bobsprit wrote in message <20000719073253...@ng-fk1.aol.com>...
Capt. Neal®
large wave and several smaller waves trailing off behind.
The one large wave traps the vessel in its trough and the
vessel cannot climb out. The speed this wave travels limits
the speed the vessel can travel since there is not enough
power in the sails to enable the vessel to climb out of the
trough. The hull shape, LWL, and powered forward motion of
the vessel determines the size, shape and speed of this
large wave.
Hull speed is actually a misnomer. It should be called wave
train speed.
Respectfully,
Capt. Neal
~~~~~~~~~~~~~
Capt. Neal®
I have proven to these putzes that, documented in my log, is
a voyage from Panama City, FL to Egmont Key (St. Petersburg,
FL) where Comorado AVERAGED over seven knots. (7.2) This is
actual, honest progress over the ground in a 36-hour period
and there is very little current in the Gulf of Mexico to
bolster the SOG.
A big part of the secret is the keel. It is a forerunner to
the famous Scheel keel but I have modified it a bit to make
it have a little more lift and a little less drag. I used
studies conducted by NACA years ago and tailored the shape
to match one of their foils best suited to the velocities in
question. The designer had gotten it pretty close but I put
the final touches on it.
Respectfully,
Capt. Neal
~~~~~~~~~~~~~
Gilligan wrote in message
<2a36cc02...@usw-ex0107-049.remarq.com>...
Ulysses
> A big part of the secret is the keel. It is a forerunner to
> the famous Scheel keel but I have modified it a bit to make
> it have a little more lift and a little less drag. I used
> studies conducted by NACA years ago and tailored the shape
> to match one of their foils best suited to the velocities in
> question. The designer had gotten it pretty close but I put
> the final touches on it.
>
Really. . .
What NACA foil did you use Neal?
Ulysses, the eminately useless
Dduelin
Exact definitions are great, assuming smooth water. Where I sail, I am often
in the ocean where wave patterns upset the laboratory setting.
How do wave trains affect our calculations, assuming wave heights equal to
or greater than the height of the trochodial wave produced by the hull in
motion?
I think of a situation where I am deep reaching, with well established wind
waves or a ground swell coming from nearly aft, the wave train moving at
maybe 125-150% of my boatspeed.
Each time the stern rises to the next wave, the knot meter jumps up a knot
or two or four depending on wind strength and swell height. The wave makes
its way forward, the hull trims level, then bow-up as the swell wave moves
on. Bow-up the speed slows to a knot or so less than what it would have been
in smooth water. Average speed over time is greater than smooth water, yet
the boat never actually "surfed" on top of the water in a less than
displacement mode.
???
Dave
Rich Hampel <"RXXhmpL33"@att.net remove XX to reply> wrote in message
news:ppkd5.6960$o71.4...@bgtnsc04-news.ops.worldnet.att.net...
> > Can someone explain the physics of Hull Speed in VERY SIMPLE terms. I
was
> > trying to explain it to someone last week and by the time I was done I
had
> > confused myself!!!
> > So....tell me like a 2 year old....explain Theoretical Hull Speed, so I
can
> > relay to my friend. Doug, Marty?
> >
> > Thanks,
> >
> > Robert B
Rich Hampel
specific to each wave and that circulation of water in the train is seen by the knot meter, hence
the 'jump' in speed.
It all averages out mathematically, as your knot meter actually see the circulation first in one
direction then the opposite direction but all the while the vessel is still moving - relativity.
The true velocity would be shown on a knotmeter that has an 'averaging' function.
Capt. Neal®
or something like that. It seems like there were fours and
two's but I can't say for sure. It has been too many years
ago to remember such minutia.
Ulysses wrote in message ...
Douglas S. King
> >
> > Doug, Rich, others...
> >
> > Exact definitions are great, assuming smooth water. Where I sail, I am often
> > in the ocean where wave patterns upset the laboratory setting.
Yup. Funny, ain't it?
"In theory, there's no difference between theory and practice. In practice, there is."
> > How do wave trains affect our calculations, assuming wave heights equal to
> > or greater than the height of the trochodial wave produced by the hull in
> > motion?
Even waves of less amplitude than th hull's generated wave train affect the boat's speed and the net
wave-making resistance. Many, many different principles at work here, though.
> > I think of a situation where I am deep reaching, with well established wind
> > waves or a ground swell coming from nearly aft, the wave train moving at
> > maybe 125-150% of my boatspeed.
> >
> > Each time the stern rises to the next wave, the knot meter jumps up a knot
> > or two or four depending on wind strength and swell height. The wave makes
> > its way forward, the hull trims level, then bow-up as the swell wave moves
> > on. Bow-up the speed slows to a knot or so less than what it would have been
> > in smooth water. Average speed over time is greater than smooth water, yet
> > the boat never actually "surfed" on top of the water in a less than
> > displacement mode.
> >
> > ???
Yup! Since the waves are traveling faster than you are, of course they're going to increase your
speed even if the back slope slows you down- that back slope is still moving.
> Rich Hampel wrote:
> Sorry but a wave train approaching from the stern will cause a circulation of water, local and
> specific to each wave and that circulation of water in the train is seen by the knot meter, hence
> the 'jump' in speed.
> It all averages out mathematically, as your knot meter actually see the circulation first in one
> direction then the opposite direction but all the while the vessel is still moving - relativity.
> The true velocity would be shown on a knotmeter that has an 'averaging' function.
Rich brings up a very important point, which is necessary if you're going to move beyond a very
simplistic view of waves. The individual water molecules do not travel with the wave (other than the
ones right at the crest) nor do they simply move straight up and down. They move in a circle
vertically, in a plane 90 degrees to the direction the wave is traveling. So the water of an
oncoming wave is actually moving backwards, up into the wave; water on the retreating face of the
wave is moving in the same direction as the wave. At the crest, some of the water will have enough
energy imparted by the wind to break free of it's viscosity and tumble along as fast or faster than
the crest.
Wind across the surface of water will also generate current as well as a wave train. So the
individual molecules are drifting slowly downwind while also making the Zappa-esque vigorous
circular motion described above.
Meanwhile, back to Dave's question- your boat may never feel like it's surfing beyond hull speed,
but the slope of oncoming waves will accelerate it, and the deceleration on the back of the wave is
relative to the new higher speed. Your knotmeter is reading speed through the water, which of course
is moving in the same direction at that point. So even if your knotmeter shows the same average
speed (which I believe is what you were saying) you'll net a higher average.
Then we can look at the suppression of the hull's wave train by surface waves- every time the bow is
in a trough, the bow wave is out of phase with the surface waves and will be diminished, reducing
the wave-making drag on the hull. Another consideration is the boat's acceleration and deceleration
vertically- this energy has to come from somewhere.
Wait a minute, this is getting too darn complicated.
Dave, don't sail in waves any more. Problem solved!
Katysails
the final touches on it.
Oh...that must have been when you welded all those tire irons along the bottom
of your keel......
katysails
S/V Chanteuse
Kirie Elite Mark ll
"Women and cats will do as they please, and men and dogs should relax
and get used to the idea." - Robert A. Heinlein
Ulysses
You *do* know that the first digit of four digid NACA foils gives the max
camber, and that the second gives the position of max camber. Thus, all
symmetrical foils are of the form 00**. Are you sure you don't remember a
couple of zeros in there? Or does your C27 do MUCH better on one tack
than the other?
ahahahahaha!
Ulysses, getting more useless all the time
On Thu, 20 Jul 2000, Capt. Neal® wrote:
> You know, I cannot recall the number. It may have been 2441
> or something like that. It seems like there were fours and
> two's but I can't say for sure. It has been too many years
> ago to remember such minutia.
>
>
> Ulysses wrote in message ...
> On Wed, 19 Jul 2000, Capt. Neal® wrote:
>
> > A big part of the secret is the keel. It is a forerunner
> to
> > the famous Scheel keel but I have modified it a bit to
> make
> > it have a little more lift and a little less drag. I used
> > studies conducted by NACA years ago and tailored the shape
> > to match one of their foils best suited to the velocities
> in
> > question. The designer had gotten it pretty close but I
> put
> > the final touches on it.
> >
>
> Really. . .
> What NACA foil did you use Neal?
>
> Ulysses, the eminately useless
>
>
>
>
____________________________________________
"And what is good, Phaedrus,
And what is not good--
Need we ask anyone to tell us these things?"
- Robert Pirsig
____________________________________________
Douglas S. King
> > > A big part of the secret is the keel. It is a forerunner to
> > > the famous Scheel keel but I have modified it a bit to make
> > > it have a little more lift and a little less drag. I used
> > > studies conducted by NACA years ago and tailored the shape
> > > to match one of their foils best suited to the velocities in
> > > question. The designer had gotten it pretty close but I put
> > > the final touches on it.
>
> > Really. . .
> > What NACA foil did you use Neal?
>
> > You know, I cannot recall the number. It may have been 2441
> > or something like that. It seems like there were fours and
> > two's but I can't say for sure. It has been too many years
> > ago to remember such minutia.
>
> Really. . .
> You *do* know that the first digit of four digid NACA foils gives the max
> camber, and that the second gives the position of max camber. Thus, all
> symmetrical foils are of the form 00**. Are you sure you don't remember a
> couple of zeros in there? Or does your C27 do MUCH better on one tack
> than the other?
BUSTED!
If anybody needs proof that the Crapton is too dumb to pound sand, here it
is. Sometimes it seems he is actually stupid enough to believe his own BS.
Does he even own a Coronado 27, or does he just say he does because he thinks
it will impress people?
Well, maybe we should give him credit for being smart enough to keep his
prattle out of the hull speed thread.
-DSK
Capt. Neal®
At one time, I did consider adding a curved end plate like
you can see on the wing tips of some light aircraft. The
purpose was to elongate the keel without adding depth and
help control the tip vortex.
I chucked the idea because Comorado is not a racing machine
but a safe, solid, fast cruiser. The extra complication and
chances of fouling an anchor rode were not worth the very
slight potential speed differential.
Respectfully,
Capt. Neal
~~~~~~~~~~~~~
Katysails wrote in message
<20000720102025...@ng-fo1.aol.com>...
>The designer had gotten it pretty close but I put
>the final touches on it.
>
>
Capt. Neal®
I think you are mistaken however as a keel, in actuality can
be composed of two identical foils back to back. The NACA
foil I used was shaped more like an airplane's wing in cross
section although with much greater chord.
I think you are trying to get me to bite a hook with pretty
sparce bait.
Respectfully,
Capt. Neal
~~~~~~~~~~~~~
Ulysses wrote in message ...
Really. . .
You *do* know that the first digit of four digid NACA foils
gives the max
camber, and that the second gives the position of max
camber. Thus, all
symmetrical foils are of the form 00**. Are you sure you
don't remember a
couple of zeros in there? Or does your C27 do MUCH better
on one tack
than the other?
ahahahahaha!
Ulysses, getting more useless all the time
On Thu, 20 Jul 2000, Capt. NealŽ wrote:
> You know, I cannot recall the number. It may have been
2441
> or something like that. It seems like there were fours and
> two's but I can't say for sure. It has been too many years
> ago to remember such minutia.
>
>
> Ulysses wrote in message ...
> On Wed, 19 Jul 2000, Capt. NealŽ wrote:
>
> > A big part of the secret is the keel. It is a forerunner
> to
> > the famous Scheel keel but I have modified it a bit to
> make
> > it have a little more lift and a little less drag. I
used
> > studies conducted by NACA years ago and tailored the
shape
> > to match one of their foils best suited to the
velocities
> in
> > question. The designer had gotten it pretty close but I
> put
> > the final touches on it.
> >
>
> Really. . .
> What NACA foil did you use Neal?
>
Ulysses
> If memory serves, I do not remember a couple of zeros.
>
> I think you are mistaken however as a keel, in actuality can
> be composed of two identical foils back to back.
Are you suggesting that you used two asymmetrical foils back to back to
make a symmetrical one? You're reaching hard Neal. What would be the
point? If you knew anything about airfoils (which you obviously
don't) you'd see the naked idiocy of that statement.
> The NACA
> foil I used was shaped more like an airplane's wing in cross
> section although with much greater chord.
NACA foils don't specify chord length. We now get to those other two
pesky digits in the NACA foil number. They give the max thickness in
percent of the total chord. Thus the airfoil scales with the chord
length.
And aircraft foil sections, with the exception of stunt planes, are are
asymmetrical. Keels are symmetrical. I pray to God your keel doesn't
look like an normal aircraft section, as you would generate unequal lift
on opposite tacks.
Come on Neal, I was man enough to admit my ignorance and learn when it
came to navigation. Can you do the same? Or have you ceased learning?
Ulysses, slowly learning to unlearn all that he has learned
Ulysses
> At one time, I did consider adding a curved end plate like
> you can see on the wing tips of some light aircraft. The
> purpose was to elongate the keel without adding depth and
> help control the tip vortex.
>
Yeah. In aircraft we like to call those winglets. On the end of a keel
we like to call that a wing keel. Hey Cappie, did you pick up all this
new found aerodynamics knowledge from my past posts on the topic? By the
way, you find winglets on all types of aircraft, light and heavy. Even
the newer 747s have them.
Man, even Jax knows more than you about aero stuff. You should be
ashamed.
Ulysses, uselessly striving for nothing
Ching and Bob Walters
>be composed of two identical foils back to back. The NACA
>foil I used was shaped more like an airplane's wing in cross
Mr. Capt.
Please do not log on to this NG when you're drunk and/or having one of those
"moments".
Bob
Bobsprit
it will impress people?>>
Yes, the crack whores are very impressed. But he tells the blind girlscouts
that it's a Pearson 30!
JAXAshby
>Can someone explain the physics of Hull Speed in VERY SIMPLE terms.
Well, for the first thing -- from a physics point of view -- there is no such
thing as THEORETICAL Hull Speed. None. The term was used to explain some
hundred years ago to British Naval brass (who understood trig) why their
(newly) powered boats didn't go that much faster when they doubled the size of
the engine.
The explanation *those* guys got (and which has taken on a life of its own
since such that many people believe it to be fact, which it most definitely is
NOT) was that a boat would go faster and faster making a longer wave until the
boat sat in the trough with the bow at the head of one wave and the stern at
the head of the following wave. Then it was stated (not true, but good enough
for the heavy displacement boat of the British navy of the time) that the boat
had to "climb over the bow wave" and the effort became impossibly high. To
this day some people believe that "the Theory" states that the bow wave
climbing effort is "exponential" and thus impossible to exceed.
A couple of things, "climbing the bow wave" is NOT exponential at all, but
rather "geometric". (Note: hp required to drive a boat *through* the water is
exponential. In fact, it is cubic, meaning it goes up at the *cube* of boat
speed.) This means that at "Hull Speed" the *extra* effort to climb the bow
wave is Zero (0.00), for the extra effort is hp required for HS divided by the
cosine of the squat angle. At HS, cosine of squat angle = 1, thus no
additional effort. In fact, because this function is "geometric" there is
almost no effect at all due to squat angle until boat speed gets over about
120% of HS. Even by 150% HS, the extra effort due to math of climbing the bow
wave is not truely excessive. It's at 200% to 300% of HS that the trig starts
to really matter.
However, there is no law in physics whatsoever that states that a boat has to
"climb the bow wave" rather than slice through the wave. In fact, Hobie cats
with their long, thin hulls regularly exceed 4x and even 5x HS. A 18-foot
displacement Hobie will easily outrun a 50-foot normal cruising sailboat or
even a 20-foot planing C-Scow. (Like a good woman, the hull(s) of a good boat
is/are thin and fast.)
Now back to the British navy. Heavy, wide, deep naval boats of the time would
go *maybe* about 1.3*sq rt lwl with the engines available (they would, and
did, go faster under sail. In fact sometimes so fast they actually sunk
beneath the waves according to Royce.). And the British brass hats nodded in
understanding.
Today, a displacement sailboat can reasonably be expected to be driven at 1.2
to 2.0 * sq rt lwl, depending on the particular boat (I've seen Melges 24's
moving out at over 9 kts).
Again, there is no such thing as *Theoretical Hull Speed* in physics. Only in
sailing books written by people who are repeating what they read in other
sailing books.
Capt. Neal®
Ulysses wrote in message ...
"Are you suggesting that you used two asymmetrical foils
back to back to
make a symmetrical one?"
YES! How the hell else do you expect a keel to work? Take
any fin keel, slice it lengthwise and you have two identical
shapes that, in cross section, look similar to the cross
section of an airplane wing, although much thicker.
"You're reaching hard Neal. What would be the
point? If you knew anything about airfoils (which you
obviously
don't) you'd see the naked idiocy of that statement."
The point is explained above. A sailboat keel is, in effect
a double-sided wing. Of course it would provide more
efficient lift if it were single sided, asymetrical but that
would only work on a proa or some other craft built to run
only on one tack.
Angle of attack is the factor that makes a double-sided foil
work. You should know this.
Respectfully,
Capt. Neal
~~~~~~~~~~~~~
Capt. Neal®
mortified and ashamed.
~~CN
Ulysses wrote in message ...
On Thu, 20 Jul 2000, Capt. NealŽ wrote:
JAXAshby
>By the
>way, you find winglets on all types of aircraft, light and heavy. Even=20
>the newer 747s have them.
>
>Man, even Jax knows more than you about aero stuff.
I first saw winglets on a working aircraft back with the very first (Volkswagen
powered) Vari-EZ. End-plates predated that by close to forty years.
Ulysses
>
> Ulysses wrote in message ...
> On Thu, 20 Jul 2000, Capt. Neal® wrote:
>
>
> "Are you suggesting that you used two asymmetrical foils
> back to back to
> make a symmetrical one?"
>
> YES! How the hell else do you expect a keel to work? Take
> any fin keel, slice it lengthwise and you have two identical
> shapes that, in cross section, look similar to the cross
> section of an airplane wing, although much thicker.
>
Neal, all I'm trying to get across to you is that a keel is a symmetric
foil. It is a useless complication to look at it as two foils joined
together, as the lower surfaces of said foils would be within the keel and
thus have no effect. A keel is ONE foil. And that one foil, if its a
four digit NACA, is of the form 00**. Probably somewhere from 0008 to
0025.
> "You're reaching hard Neal. What would be the
> point? If you knew anything about airfoils (which you
> obviously
> don't) you'd see the naked idiocy of that statement."
>
> The point is explained above. A sailboat keel is, in effect
> a double-sided wing.
All wings are double sided. See below.
Of course it would provide more
> efficient lift if it were single sided, asymetrical but that
> would only work on a proa or some other craft built to run
> only on one tack.
>
You seem to be confused about "double sided" and "cambered"(As you
were before about "thickness" and "chord"). Every foil has two sides, how
could it not? The difference here is that both sides are the same. But
at least you understand why keels are symmetric.
Ulysses
JAXAshby
>Angle of attack is the factor that makes a double-sided foil
>work. You should know this.
Yes, Capt, he should. And he would too, if only he had taken a course or two
in aeornautics.
btw Capt, have noticed that Useless refers to airfoil shapes by their "NACA"
number, a term that went out in 1958 when NACA became NASA?
JAXAshby
>If JAX knows more about ANYYHING than I do then I'm
>mortified and ashamed.
>
I dunno, cap, but maybe sex with live women?
Dirk Schleaderhausen
<Capt...@Bigfoot.com> wrote:
> Again, another brilliant post from Gilligan.
>
> I have proven to these putzes that, documented in my log, is
> a voyage from Panama City, FL to Egmont Key (St. Petersburg,
> FL) where Comorado AVERAGED over seven knots. (7.2) This is
> actual, honest progress over the ground in a 36-hour period
> and there is very little current in the Gulf of Mexico to
> bolster the SOG.
>
> A big part of the secret is the keel. It is a forerunner to
> the famous Scheel keel but I have modified it a bit to make
> it have a little more lift and a little less drag. I used
> studies conducted by NACA years ago and tailored the shape
> to match one of their foils best suited to the velocities in
> question. The designer had gotten it pretty close but I put
> the final touches on it.
>
> Respectfully,
> Capt. Neal
a piss yellow coronado 27 AVERAGING over 7 knots. have you lost your
mind neal? care to explain how you managed to get it moving 7 knots
through the water at any time, let alone averaging 7.2 for the entire
trip.
do you think people actually believe this bullshit?
another one for the joke book...it just keeps getting better!
Dirk
Dduelin
shapes included in the NACA wind tunnel studies of the '30's, nor the NACA
prefix.
Dave
JAXAshby <jaxa...@aol.com> wrote in message
news:20000723193958...@ng-fv1.aol.com...
Ulysses
> Capt. Neal writes of Usless:
>
> >Angle of attack is the factor that makes a double-sided foil
> >work. You should know this.
>
> Yes, Capt, he should. And he would too, if only he had taken a course or two
> in aeornautics.
>
> btw Capt, have noticed that Useless refers to airfoil shapes by their "NACA"
> number, a term that went out in 1958 when NACA became NASA?
>
NACA numbers are still refered to as such because the research was done by
NACA, and such an extensive cataloguing of airfoils and their properties
has never been done since (certainly not by NASA). Granted, this is
because through numerical flow sovers we can now optimize each design to
its specific needs; the use of pre-studied and catalogued airfoils for
aircraft design is somewhat obsolete.
Nonetheless, the NACA families of airfoils remain a good starting point
from which to tweak your airfoil, as are several other catalogues such as
Abbott and von Doenhoff's Theory of Wing Sections, and others. And
occaisionally can be used as is.
The use of the name NACA when refering to their catalogue hardly "went
out" in the 50's. "Hep" and "Daddy-o" went out in the 50's. "NACA
64-010" still means something to any engineer dealing with fluid dynamics.
Ulysses
Stanford
BS '00
Aero/Astro Engineering
Douglas S. King
> > >Angle of attack is the factor that makes a double-sided foil
> > >work. You should know this.
>
> > Yes, Capt, he should. And he would too, if only he had taken a course or two
> > in aeornautics.
That's odd, I always thought that one selected a foil section for it's lift/drag
profile within a desired range of angle of attack. What's even odder is that a few
professors of aerospace engineering and fluid dynamics and kinematics (look it up)
think so too. Of course they can't possibly be as smart as the Crapton and
JAXAshcan.
Or it could be that our two resident newsgroup clowns are simply trying to BS
their way out this big hole they've dug. Isn't it amusing to see a moron attempt
to prove he's not one?
I know! Let's see either or both of them attempt to explain Reynold's Numbers!
> > btw Capt, have noticed that Useless refers to airfoil shapes by their "NACA"
> > number, a term that went out in 1958 when NACA became NASA?
>
> Ulysses wrote:
> NACA numbers are still refered to as such because the research was done by
> NACA, and such an extensive cataloguing of airfoils and their properties
> has never been done since (certainly not by NASA). Granted, this is
> because through numerical flow sovers we can now optimize each design to
> its specific needs; the use of pre-studied and catalogued airfoils for
> aircraft design is somewhat obsolete.
>
> Nonetheless, the NACA families of airfoils remain a good starting point
> from which to tweak your airfoil, as are several other catalogues such as
> Abbott and von Doenhoff's Theory of Wing Sections, and others. And
> occaisionally can be used as is.
Yup. There are relatively few NACA foils still used in new design, they have since
been improved on for almost every specialty application. But they are still the
baseline.
> The use of the name NACA when refering to their catalogue hardly "went
> out" in the 50's. "Hep" and "Daddy-o" went out in the 50's. "NACA
> 64-010" still means something to any engineer dealing with fluid dynamics.
Maybe JAXAssbo has been wondering all these years why he gets funny looks when he
starts talking about "NASA foil sections." He's not hep to that jive, Daddy-o!
At least this little exchange has been fairly comical, although Jax and the
Crapton appear to be serious.
JAXAshby
>The name change to NASA did not change the reference numbers to airfoil
>shapes included in the NACA wind tunnel studies of the '30's, nor the NACA
>prefix.
>
Then things changed ... and changed back. NACA airfoils were (are?) foils from
the 30's and so up to the late 50's. NASA foils are (were?) the foils since
that time. Lots more NASA foils than NACA. Lots. But maybe the nomenclature
has changed yet again?
JAXAshby
>> > Capt. Neal writes of Usless:
>> > >Angle of attack is the factor that makes a double-sided foil
>> > >work. You should know this.
>>
>> JAXAshby wrote:
>> > Yes, Capt, he should. And he would too, if only he had taken a course or
>two
>> > in aeornautics.
>
>That's odd, I always thought that one selected a foil section for it's
>lift/drag
>profile within a desired range of angle of attack. What's even odder is that
>a few
>professors of aerospace engineering and fluid dynamics and kinematics (look
>it up)
>think so too. Of course they can't possibly be as smart as the Crapton and
>JAXAshcan.
dougie, WHAT in the hell are you talking about?
Douglas S. King
> dougie, WHAT in the hell are you talking about?
I am impressed by your honesty.
And this is a positive step for you. Admitting you don't know is the beginning of
learning!
Fresh Breezes- Doug "no E in my name" King
Ulysses
> doug king writes:
>
> >That's odd, I always thought that one selected a foil section for it's
> >lift/drag
> >profile within a desired range of angle of attack. What's even odder is that
> >a few
> >professors of aerospace engineering and fluid dynamics and kinematics (look
> >it up)
> >think so too. Of course they can't possibly be as smart as the Crapton and
> >JAXAshcan.
>
>
> dougie, WHAT in the hell are you talking about?
>
Exactly.
-U
Dirk Schleaderhausen
<Capt...@Bigfoot.com> wrote:
> Again, another brilliant post from Gilligan.
>
> I have proven to these putzes that, documented in my log, is
> a voyage from Panama City, FL to Egmont Key (St. Petersburg,
> FL) where Comorado AVERAGED over seven knots. (7.2) This is
> actual, honest progress over the ground in a 36-hour period
> and there is very little current in the Gulf of Mexico to
> bolster the SOG.
>
> A big part of the secret is the keel. It is a forerunner to
> the famous Scheel keel but I have modified it a bit to make
> it have a little more lift and a little less drag. I used
> studies conducted by NACA years ago and tailored the shape
> to match one of their foils best suited to the velocities in
> question. The designer had gotten it pretty close but I put
> the final touches on it.
>
> Respectfully,
> Capt. Neal
> ~~~~~~~~~~~~~
hey neal, the only thing that you've proven is that your "log" is full
of fallacies.
remember, you had trouble differentiating between 42,000 miles and
4,200 miles. that's not a mistake, it's either gross incompetence or a
deliberate attempt to make yourself something you're not...a sailor.
Dirk
JAXAshby
engineer -- Chell writes:
>On 25 Jul 2000 21:51:05 GMT, jaxa...@aol.com (JAXAshby) wrote:
>
>Keep shovlin' Jackass
>
>>
>>Then things changed ... and changed back. NACA airfoils were (are?) foils
>from
>>the 30's and so up to the late 50's. NASA foils are (were?) the foils since
>>that time. Lots more NASA foils than NACA. Lots. But maybe the
>nomenclature
>>has changed yet again?
>
Sorry, ed, were the words too big for you? You wanna explain to the world the
lost genuis of the Canberra bomber?
Ulysses
> Sorry, ed, were the words too big for you? You wanna explain to the world the
> lost genuis of the Canberra bomber?
>
The first Limey jet bomber made after the war. We copied it and made it
the B-57. Saw action in the Korean and Vietnam conflicts, as well as
several other conflicts at the hands of people we sold it to. A fairly
versitile plane, it was, for a time, part of the SAC, filling the role of
second strike nuclear delivery vehicle. It also saw service as a high
altitude (about 50,000 ft. high for the time) reconaissance plane, before
the production of the U-2. A few were equipped with night vision to try
to disrupt night time movement on the Ho Chi Minh Trail.
Straight wings before the nacelles, tapered thereafter, a somewhat largish
tail with not much sweep. Later models had a rotary bomb bay and hard
points on the wings. All in all a worth while aircraft, but what exactly
is the "lost genious?"
Ulysses
JAXAshby
>jaxa...@aol.com (JAXAshby) wrote:
>
>>Sorry, ed, were the words too big for you? You wanna explain to the world
>the
>>lost genuis of the Canberra bomber?
>
>Nah Jackass, you wouldn.......................................
>Hang on the kettle's boiling ..............................
>........................................................................
>No, it wasn't
>That whistle must have been the wind.............
>.........................................................................
>Blowing thru that vacancy in your head.
>
Yup. Like I thought. The dumb bunny doesn't know what a Canberra was. Hey,
eddie, a Canberra was a flying abortion. But it was as good as the best minds
in aussie aviation could come up with.
You do have an aussie education in aeronatics, don't you? (Sic 'em, Use. Sic
'em.)
Ulysses
I wrote:
> >The first Limey jet bomber made after the war. We copied it and made it
> >the B-57. Saw action in the Korean and Vietnam conflicts, as well as
> >several other conflicts at the hands of people we sold it to. A fairly
> >versitile plane, it was, for a time, part of the SAC, filling the role of
> >second strike nuclear delivery vehicle. It also saw service as a high
> >altitude (about 50,000 ft. high for the time) reconaissance plane, before
> >the production of the U-2. A few were equipped with night vision to try
> >to disrupt night time movement on the Ho Chi Minh Trail.
> >
> >Straight wings before the nacelles, tapered thereafter, a somewhat largish
> >tail with not much sweep. Later models had a rotary bomb bay and hard
> >points on the wings. All in all a worth while aircraft, but what exactly
> >is the "lost genious?"
> >
>
> Use, it was a piece of shit as an aircraft.
>
It has a decent combat record, and General Dynamics kept getting contracts
to pump them out (the U.S. clones that is). I'm curious, what was so
wrong with it?
-U
JAXAshby
>On 27 Jul 2000, JAXAshby wrote:
>
>> Sorry, ed, were the words too big for you? You wanna explain to the world
>the
>> lost genuis of the Canberra bomber?
>>
>
JAXAshby
A Canberra was a joke put out by aussies who were pretending to know how to
design aeroplanes.
Now, IF you wish to say otherwise it IS your life. Do what you will.
JAXAshby
>Jackass please get back on the medication.
>Seems about every 2 or 3 weeks you have a lapse.
>Look at the links below, if you can see thru the fog there is
>enlightenment.
>
>http://www.sacmuseum.org/aircraft/b-57.html
>
>http://www.kiwiaircraftimages.simplenet.com/canberra.html
>
>http://www.topedge.com/panels/aircraft/sites/gustin/br/CANBERRA.html
>
>http://www.raf.mod.uk/front_line/canberra.html
>
>http://www.worldsweapons.freeservers.com/england/planes/canberra.htm
>
>http://www.wpafb.af.mil/museum/research/bombers/b5/b5-6.htm
>
>http://www.wpafb.af.mil/museum/research/bombers/b5/b5-10.htm
>
>Ed Chell
>
Eddie, you clown. Did you ever bother to READ those sites? Here you spent all
night long seaching the web for info on that dumb aircraft (of which less than
a thousand were ever built) for this:
"Entering service with RAF Bomber Command in 1951, the Canberra Outperformed
contemporary fighters...
(note: "comtempory fighters" were piston/prop powered left-over fighter planes
from WW Deuce)
... Even when carrying its full 2722-kilogram bomb load it was very
maneuverable...
(Yup, that turkey carried less than 6,000 # of bombs, less than an early 1940's
B-17 could carry and less than 30% of what a super-sonic 1955 Phanton *fighter*
plane carried.)
... Equipped for visual bombing only,...
(Really??!! *Visual bombing* from 45,000 -- eight miles -- feet up?? Yup,
that's one fine aircraft.)
... due to problems radar system, the Canberra was soon modified as a
reconnaissance platform..."
(in other words, such a piece of shit it was it was relegated to reconnaissance
work, a job it was FAR less good at than a 1950's U-2.)
btw: the Argentines DID use Canberras against the British in the Falklands.
Boy, were they effective.
d parker
Hey Jax,
I dont know about that. We arent the ones that developed the stealth
fighters and bombers. We Aussies, are the only ones who can get 'em on radar
though. Cant be too dumb down under!
D Parker
Scott Vernon
ED CHELL == 22
JaxASS ==== 00
Ed Chell wrote in message <0iubosce3shj21fse...@4ax.com>...
>On 31 Jul 2000 21:59:36 GMT, jaxa...@aol.com (JAXAshby) wrote:
>
>>
>>Eddie, you clown. Did you ever bother to READ those sites? Here you
spent all
>>night long seaching the web for info on that dumb aircraft (of which less
than
>>a thousand were ever built) for this:
>
>No Jackass just one simple click on MSN search site. You really should
>try it BEFORE launching into one of your episodes, the facts are there
>for anyone to read. Your problem seems to be more with comprehension.
>>
>> "Entering service with RAF Bomber Command in 1951, the Canberra
Outperformed
>>contemporary fighters...
>>
>>(note: "comtempory fighters" were piston/prop powered left-over fighter
planes
>>from WW Deuce)
>
>Umm Jackass It was built to outperform the fighters of the time
>It flew higher than them all
>SO IT COULD AVOID THEM. It was one of the first jets and as such was
>bound to be quickly ................Oh forget it ..............
>>
>>... Even when carrying its full 2722-kilogram bomb load it was very
>>maneuverable...
>>
>>(Yup, that turkey carried less than 6,000 # of bombs, less than an early
1940's
>>B-17 could carry and less than 30% of what a super-sonic 1955 Phanton
*fighter*
>>plane carried.)
>
>UMM Jackass the Phantom came into service a little later than that I
>think (could be wrong ) and was developed and continually improved in
>a truly dynamic era of jet design.
>Do you really have any clue?? (Stupid question)
>Sorta like the last 10 years of computers (Do you understand what I
>mean?) Nah, not likely eh
>The B17 was fighter food that's why they built and lost so many not
>maeuverable and was heavily armed for that reason. (13machine guns)
>Jesus the fuel tanks were built to self seal, it took so many hits
>It was a truck designed only for delivery of as big a load as possible
>relying heavily on weight of numbers and fighter support. Oh and it
>was a high altitude visual bomber with a normal payload of 6000lbs,
>sure it could double that and usually did but then was extremely
>vulnerable
>Different concept, understand Jackass?
>
>Nah not likely, huh?
>>
>>... Equipped for visual bombing only,...
>>
>>(Really??!! *Visual bombing* from 45,000 -- eight miles -- feet up?? Yup,
>>that's one fine aircraft.)
>Ahh no Jackass they came down a little to drop the bombs don't you
>think?
>>
>>... due to problems radar system, the Canberra was soon modified as a
>>reconnaissance platform..."
>
>Thought you said it was a visual only bomber.
>BTW it made an excellent recon aircraft at moderate altitudes then
>that damn technology march brought about the intro of the U2
>>
>>(in other words, such a piece of shit it was it was relegated to
reconnaissance
>>work, a job it was FAR less good at than a 1950's U-2.)
>
>The U2 didn't make its first flight till '55 you Jackass
>>
>>btw: the Argentines DID use Canberras against the British in the
Falklands.
>>Boy, were they effective.
>What year was the Falkland "war" Jackass.
>Oh and the Argentines used lots of things against the British (you
>know that little island across the other side of the World from here,
>I live on that big island, the one the same size as the USA) and few
>were effective 'cept a missile or two
>
>You really do have a problem with dates Jackass to say nothing og any
>grasp of the rate that technology was accelerating back then and
>continues now.
>
>You continue to make your wild statements and never retract when
>proved wrong. It's entertaining to watch you grasp and squirm.
>Truly your name suits, JACKASS!
>
>Ed (meeeow)
>
JAXAshby
((snip lots of eddie's bs))
eddie, that "visual" ("visual" Christ, it was such a poor excuse of an aircraft
they blamed "radar", which was available from WW Deuce aircraft, as the reason
it couldn't fly missions) bomber cum reconnaisance aircraft had a service
ceiling of a ME-109 and wasn't any faster than an ME-260 or -262. It carried
way too little payload, and just 20 months after it made it onto airfields, the
America F-80's and F-86's and the Soviet MIG-15's had a greater service
ceiling, greater rate of climb, better avionics, better weaponry and better
manuverability.
btw: it is interesting that you claim all your knowledge of the aircraft came
from (using your words) "just one simple click on MSN search site". Not many
people would proudly claim they knew what they were talking about from "just
one simple click on MSN".