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Author Topic: seeking an answer...  (Read 29208 times)

mobile_bob

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seeking an answer...
« on: November 12, 2006, 07:07:15 AM »
sometimes i am known for being like a dog on a bone, most especially when i am trying to get to an answer to a specific question.

being told that is just the way it is, rarely will suffice, usually i need to know the why's or the why not's

this is usually compounded by gut feelings, observation, experience and by intuition, basically if it don't feel right, i begin to question.

on a related post i asked whether a lister/oid was a machine, got no answers, so i will for the sake of an arguement take the position that the engine is not a machine,
until it is coupled to a generator it then becomes part of a machine.

now our genset has become a machine by virtue of common definition, and thru much debate here the common consensus is the engine must be rigidly mounted to the frame, and commonly the genhead is also rigidly bolted to the frame, thus the engine, genhead and frame all become a machine known as a genset.

(i really am going somewhere with this)

in Audel's mechanical trades pocket manual, 4th edition, the following:

machinery mounts, in short

"in manufacturing plant , machine's are no longer rigidly mounted to the floor..."

"because of the ever increasing variety of industrial machines, the problems associated with vibration, shock, and noise in addition to that of mobility have become important considerations"

" shock and vibration damping machine mounts, eliminate the need to anchor a machine to the concrete floor..."

and this (which gives rise to my continued search for a concise answer):

"another very important benefit resulting from the use of vibration damping mounts is the reduction of internal stresses in the machine"

"when vibrating equipment is rigidly bolted to the floor, an amplification of internal stresses occurs. ...the results often are undue wear on brgs and related parts"

i find the more i dig, and the more i read, the more i question

so if the lister/oid is not a machine then it can be mounted to concrete rigidly, if it is part of a genset it now becomes a machine, a machine bolted directly to concrete will have its vibration amplified with resulting stresses on the machine, which the lister/oid is part of ....

there simply has to be another explanation for the recommendation by lister to use a block of concrete
what are the options

1. the concrete block is an intregal part of the engine design?  there is no logic to support this, no documentation and certainly some issue with amplification

2. the concrete block is used as a dead weight to secure a  less than perfectly balanced engine?  likely? certainly possible

3. the concrete block is of sufficiently safe design so as to negate the need for lister to have to review engineering of hundreds of mounting schemes? most likely

i fully realize that this topic has been beat to death, but i am still trying to get to the bottom of the issue. if this topic stresses anyone my appologies, feel free to not respond.

my purpose of bringing this all back up again is one of theory. 


bob g
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contango

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Re: seeking an answer...
« Reply #1 on: November 12, 2006, 07:30:36 AM »
Bob,
I spent a couple of years responsible for a very impressive, heavy, FAST Amada Pega 345 Turret punch press. It could punch 4" holes in 11ga. 304ss. Shook the building. It "came" from Amada with four "feet" that it sat on and allowed leveling. The "feet" were rubber faced. Moved it once. Both places, never "walked". I Sharpied the feet to keep track...
Your #2 and #3 are to me very plausible.

Kevin

listerdiesel

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Re: seeking an answer...
« Reply #2 on: November 12, 2006, 08:08:47 AM »
Concrete block or raft mounting of engines has been around since the very early days of big engines, so anyone building engines had a lot of previous data/information to go on. Ruston & Hornsby, Crossley, National and others all supplied drawings for foundations for their engines, even the smallest.

It seems that it is relatively recently that flexible (as opposed to rigid) mountings became a part of the system, and even then still with the large foundation structure in place.

It seems that the smaller engines didn't have the need for flexibles until we got into the more recent use of small portable generators, and then it was more to stop the unit walking across the florr than anything else.

I believe that Lister and Petters both recommended heavy foundations more for the absorbtion of vibration than anything else, and like most things of that era they were probably over-engineered.

Most Lister and Petter engines and certainly Ruston, Crossley, National etc made portable engines on trolleys/carts that were relatively light in comparison with foundation blocks, and they did move around a lot when working, most needing chocks on the wheels or other restraining devices.

I don't have any real thoughts on the "why's and wherefores", as it is not a subject close to my heart, but there is an awful lot of information in the older engine books, including a 5-volume set on diesels by the American Technical Society which I have, that quotes a lot of figures and formulae for foundation construction from 50hp up to 500hp.

Peter

mobile_bob

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Re: seeking an answer...
« Reply #3 on: November 13, 2006, 03:34:20 AM »
while this subject is not one that is particularly close to my heart, getting to the bottom of the issue seems prudent, mainly because of broad application of the theory.

Guy Fawkes has made the assertion that the concrete base was a consideration in the original lister design.
while i have the utmost admiration for GF's input, thoughts, and knowledge, i need to get a better understanding of the need for the base.

there is the theory of moving the center of mass, into the block of concrete and in theory i can accept that as fact.

with every action there is an equal and opposite reaction, this too i accept as physical law

the concept that vibrations can me amplified in a rigid concrete base and returned to the machine in higher amplitudes is something i can also accept.

until i can arrive at an understanding of why there was a recommendation or statement that a concrete block of specific dimensions, i find it hard to accept.

while i have theories, idea's and suspicions, i realize that none of them is based in anything others than smoke or feelings

until i can find text that supports in physics or science the math/geometry or whatever that shows the need for the concrete block i am faced with accepting the recommendation on blind faith...   which is fine for religion, but not something i have room to accept in day to day life.

anyone find some text or doc's that specifiy and explain the need for concrete, other than "trust me" ?

bob g
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bitsnpieces1

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Re: seeking an answer...
« Reply #4 on: November 13, 2006, 09:00:57 PM »
  Just thinking here and considering the times these got started,  maybe it was a way to keep users from putting the engines on flimsy wooden bases and possibly a more or less common size block to pour.  So the spec. would get people to use a safer installation and give a certain CYA to the Lister co. 
Lister Petter AC1, Listeroid 12/1, Briggs & Stratton ZZ, various US Mil. surplus engines. Crosley (American) 4cyl marine engine(26hp).

mobile_bob

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Re: seeking an answer...
« Reply #5 on: November 14, 2006, 06:54:38 AM »
i suspect there is some credance to the old CYA, but this is only just another theory not something concrete (no pun intended)


so much in engineering is built up on empirical evidence, and once something has been proven out to be either sufficient and/or expedient it is only human nature to keep on with the original plan

boiled down we have basically 3 schools of thought

1. in support of concrete

    a. it was and is an intregal part of the original design

    b. the concrete base was an engineered part of the engine

    c. forces/vibration are moved from the engine proper into the concrete base

2. the use of concrete as a marketing ploy

    a. lister built engines and found them to work ok on a concrete base, negating the need for expensive and comprehensive balanceing

    b. turn a negative into a positive (marketing tool) by making the claim that the concrete is an intergal part of the engine design.

    c. homogenize the mount to one approved system, negating the need to check an approve other designs

3.  the use of concrete may not be a good thing

    a. forces/vibrations might be amplified and returned to the engine as destructive or life shortening forces

    b. vibration and noise will be transmitted to other parts of the structure, other parts of the machine or other components

    c. relocation of the complete unit will be difficult if the need arrises


and the list goes on......

the problem as i see it is,,, each of the schools of thought have equal merit, and none has an overriding basis in fact
basically because there has been no engineering figures to support any one of the three to any conclusive extent.

i have read countless books on the subject, over the last few months, and have yet to find anywhere by anyone that one system is the one true and only successful system.

it would appear that in the beginning there were stationary engine's and as such were mounted on concrete bases because of the ability to fabricate large heavy bases easily out of the material without need for expensive manpower, specialized machinery/tooling, and the fact that everyone of consequence was doing it that way.
just because its the way it has always been done, does not make it necessarily right or wrong.

then came the automobile and rigid mounted engines caused vibration to be transmitted to the passenger compartment, this is where resilient mounting came of age, and that was basically because the manufactures were trying to make their offerings more acceptable to the consumer.  meanwhile the stationary engine's remained rigid mounted, why change when no one really complained, and afterall that is the way it has always been done,,, right?

in recent years consumers of stationary equipment are trying to do more with less, usually less space, which forces people and their related office space within the same building as the offending machinery, thus the need for resilient mounting and the proliferation of isolating technologies. now machines that were once always mounted rigidly to concrete monolithic blocks are routinely mounted resiliently without hard connection to the concrete floors and foundations. hammer mills, punch presses, drop hammers, engines, etc are now mounted resiliently when in the past they were always hard mounted.

so what has changed? besides the demand for mitigation of vibration? the machines have not changed, if anything they are lighter than they were 50 or 100 years ago all the while doing the same work or in many cases heavier work.

is it not possible that the discussion now would be to blast the guy that wanted to mount his engine to a ton of concrete had stationary engines 100 years ago been routinely mounted resiliently? would the assertions be, the resilient mounts were an intregal part of the original engine design, and if you negate them you do so at your engine peril?

i really wonder, and short of some documentation by any engine manufacture showing the engineering of a concrete base being an intregal part of their engine, i will continue to question.

bob g
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GuyFawkes

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Re: seeking an answer...
« Reply #6 on: November 14, 2006, 10:15:56 AM »
sigh....

You had your answer, as did others, trouble is nobody likes the answer.



You know a lister has a centre of mass above the crankshaft axis, you know where the centre of mass of a block of concrete is, you can work out where the centre of mass of the combined system is, and you can work out how shifting this shifts and alters all the vectors of force from the reciprocating components, and when you work it out you will see how loads are reduced on the rotating machinery.

Here is an exact parallel example, the moon, being in orbit, is in a constant state of acceleration towards us, despite the fact that its angular velocity doesn't change, it is ALWAYS accelerating, same goes for satellites, earth around sun, etc etc etc.

This is easy enough to prove, you work through the math F = ma etc, and when you do that math you realise it is the only possible answer, no matter how counter intuitive or stupid or against common sense it seems.

When you work it out and understand it you realise that common sense gave you the wrong answers because common sense was founded on incorrect principle, same as the heliocentric model of the world and start moving on crystal spheres.

Newton was a genius because he did not follow common sense, he worked the numbers until he had answers that were always computationally correct............

Eratosthenes calculated the diameter of the earth by observing shadows in wells during the solstice about 230 BC
Galileo 1564-1642 calculated the acceleration due to gravity in about 1600 AD
Newton 1642-1727 calculated his second law of motion, F = ma about a hundred years later
Cavendish 1731-1810 used this to weigh the mass of the earth about fifty years later

All these people were polymaths, weighing the earth would have been enough to make cavendish famous, but he also worked out that water was oxygen and hydrogen, discovery of hydrogen, electric potential, capacitance, dielectric constant, ohms law, wheatstones law, coulombs law, again, any one of which would be a rare achievment for anyone else.

It took people like these to see beyond "common sense" and work out what was really going on.

=================================

Now, I can PROVE to you that the moon is always accelerating, even though its speed never changes, and how we go from force through right angle vectors to speed and right angle vectors to acceleration, BUT YOU HAVE TO LEARN THE MATH.

THERE IS ABSOLUTELY NO ALTERNATIVE.

When you learn this math you can then go on to prove that shifting the centre of mass outside the radius of the moving parts in our engine lowers the stresses on said parts.

==================================

WHEN you learn the math you will see that the moon once rotated, but tidal forces slowed it down until it locked into earth, and you will see that that process also had to alter the radius of the moons orbit, it all becomes beautiful and elegant.

If you do not learn the math the moon will not fall out of the sky, but you will never get a job at NASA and you will never get to walk on the moon.

==================================

Bob, when I want to be I can be a FUCKING good engineer, but I fall so far short of even lesser gods like henry ricardo and james watt and otto diesel and a string of other names whose boots I am not fit to lick it ain't even funny, and THEY worshipped people like newton and cavendish and maxwell etc.

Do you know how many patents I hold bob?

none

Do you know how many things I have truly designed bob, as opposed to assembling other peoples designs and tweaking them to fit?

none

I can go out and design a brand new internal combustion engine tomorrow, go out and build it, and it will run to spec, and I mean every last component and structure inside it will be bespoke and brand new and quite unique.

But there will not be a single component that your average mechanic will not immediately recognise for what it is.

I could get really exotic and use a swash plate instead of crankshaft and con rods, I could use aspin heads instead of poppet valves, but a good mechanic would still recognise everything for what it was.

Doug could go out and design a new electric mine train, same story, he doesn't need to invent or even truly understand ohms law, coulombs, reactance, induction or anything else, he doesn't even need to do any math, just use his judgement, and it will still work after some sort of fashion.

But to REALLY design it he will need to learn and understand all those laws, then he can build it to spec, then he can say yeah it will have a drawbar pull of 20,000 lbs and a power consumption of X and a thermal rejection of Y and a service interval of Z hours.

==============================

Outside is my car, one of these.



1.9 litre 4 pot naturally aspirated no electronics diesel, drive is nicely and it will do 60 mpg at 60 mph (imperial gallons)

They are legendary and hugely popular as taxis, 300,000 miles on a motor is not uncommon.

300,000 miles at 50 mph is 6,000 hours.

6,000 hours is absolutely nothing, inconsequential, to a Lister CS or to any other pukka stationary engine.

====================================

I've told you and others, for a fact, that the concrete block is an integral part of the design, because it shifts the centre of mass and so shifts the vectors.

You have NO OPTION but to either accept that or go learn the math, OR continue believing that the moon cannot be constantly accelerating because it is not speeding up, common sense says so.

Buzz aldrin and neil armstrong did not walk on the moon via common sense, lister did not design the cs series via common sense, they did the math, they did the engineering.

Non engineers were amazed when apollo landed on the moon within a couple of seconds of when it was supposed to before it had even left the launchpad, engineers were not, engineers knew it was not a bus going down a highway, engineers knew it has to take precisely that time if it was taking that route.

F = ma, F = GmM/r2 = ma, GM/r2= a, M = ar2/G, M = 9.8 x (6.7 x 106)2/6.7 x 10-11 = 6.0 x 1024 kg (mass of the earth as determined by cavendish) he was less than 1% out.

==============================

seeking an answer? no, you are seeking an easy and acceptable to you answer with the minimum effort.

which is Ok and quite human.

but it is not seeking an answer.

eratosthenes, galileo, newton, cavendish, they were seeking answers.

all we have to do is follow in their footsteps and learn

if we are not prepared to do that we will never learn.

I am not prepared to follow in the footsteps of watson and crick, so I have no right to seek answers about dna, I just have to accept it exists just as they say it does, and I have to accept the glib answers that geneticists must give to laity such as myself when I ask about dna fingerprinting and matching allele bases, because I am not prepared to study the subject long enough to learn the proofs.

I can fuck and make babies, as it happens there is a baby due in a few weeks, doesn't make me a geneticist, so I have no say in eye colour, genetic defects, susceptibility to cancer, or anything else, even if I wanted to or thought I should play god.
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Original Lister CS 6/1 Start-o-matic 2.5 Kw (radiator conversion)
3Kw 130 VDC Dynamo to be added. (compressor + hyd pump)
Original Lister D, megasquirt multifuel project, compressor and truck alternator.
Current status - project / standby, Fuel, good old pump diesel.

rmchambers

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Re: seeking an answer...
« Reply #7 on: November 14, 2006, 01:17:00 PM »
I've always been in awe of Newton and Faraday and those of their ilk.  As far as understanding what Newton said about laws of motion - I get that.  What amazes me is what kind of mind can take 10 steps back and figure out the relationships and then turn around and come up with the formulae to express it and have it work perfectly.  I'd have loved to have met Newton but I'm sure he would consider me a dullard in comparison if he had to explain something that was so obvious to his mind.

Congratulations on the impending birth Guy, I hope you are stockpiling some sleep now.

Regards

Robert

mobile_bob

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Re: seeking an answer...
« Reply #8 on: November 14, 2006, 07:22:44 PM »
Guy:

first of all let me give you best wishes on the birth of your child, get ready tho' you will be asked "why" millions of times by the little bugger for many years.

now to the point.

your analogy or reference if you will to the moon, tides, its orbit, etc is an interesting tangent to the question at hand.

your use of names (name dropping if you will) while being quite impeccable as a group, does not address the question at hand.

The fact that you do or do not hold patents does not take away from your intelligence or for that matter add to your intelligence, or anyone else's for that matter.

as far as math/formulae etc.

thru careful observation or experimentation certain patterns develop

patterns can be expressed mathematically

mathematically expressed patterns are at times proven out to become formulae

through formulae one can determine an outcome

interestingly i can find formulae for every facet of an engine, from volumetric efficiency to mach index's, from cylinder pressures to flame propagation and ignition timeing, connecting rod ratio's to chamber design, 1st, 2nd, 3rd, etc harmonics to resilient mounts, literally every part and parcel of an engine can and has been analized and expressed in some form of formulae, .... save one!

that being any formulae relating to the concrete rigid mount, showing the vectors, angles, math etc to clearly not only illustrate what is happening but providing proof of concept.

doesn't this ommission (sp) seem odd?

seriously and respectfully, can you or anyone direct me to the text or some formulae outlining the use of concrete as the engine base, other than some directive to do so?

it would seem to me as it should you and others that some reference material with the requisite math/formulae should exist somewhere

failing that i am left to believe that lister simply poured a concrete base that looked about right for their engine, found it to work for what they intended and simply left it at that.

why am i to accept that there was some sort of theory, math and formulae in use to determine the size of said block without some form of documentation?

mr ricardo certainly was a master and as such documented his work, is he somehow inferior to the lister engineer's? did he have to document his assertions and lister did not?

are you placing lister engineers on a higher alter, someplace above question?

i believe in things i cannot prove, such as God.

 i am unwilling to place lister on that plane.

bob g

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xyzer

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Re: seeking an answer...
« Reply #9 on: November 14, 2006, 09:13:30 PM »
I'll keep it short!

are you placing lister engineers on a higher alter, someplace above question?

i believe in things i cannot prove, such as God.

 i am unwilling to place lister on that plane.

bob g

 I am also unwilling to place lister on that plane. But will accept any factual evidence!
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GuyFawkes

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Re: seeking an answer...
« Reply #10 on: November 15, 2006, 12:02:29 AM »

seriously and respectfully, can you or anyone direct me to the text or some formulae outlining the use of concrete as the engine base, other than some directive to do so?


bob, you've had your answer a dozen times over, go and do the math, that IS the answer.

concrete was chosen simply because it is dead simple to do and always get pretty similar results, concrete will last a thousand years, we know that because there is thousand year old roman concrete right here.

if you can do the math you can substitute lead for concrete, or zinc, or pig iron, because you can do the math and work it out, even depleted uranium.

if you can't do the math use concrete.

you say I am misdirecting you with talk of the moon constantly accelerating but never changing speed, I am not, I'm trying to show you with another example because you appear to be dead set against seeing the answer being laid before you.

the moon accelerating and vibration in a lister are calculated by exactly the same math.

GO AND LEARN THE BLOODY MATH, IT IS THE ONLY ANSWER.

then you'll understand that as remarkable as newton and galilieo and cavendish were, their math did NOT solve a whole bunch of problems, such as three body celestial mechanics, kepler did that.

newtons laws work on fixed radius, there might as well be a crankshaft attaching earth and moon, that's why newtons laws work. well, they do until you look real close and see the effects of sun and other planets preturbing them.

unless you can understand mathematically enough to at least grasp mathematically the stuff on the following link (you need java) then by definition you cannot understand mathematically why a concrete block is good for lister longevity

http://faculty.ifmo.ru/butikov/Projects/Collection.html

here endeth my discussion on the subject
--
Original Lister CS 6/1 Start-o-matic 2.5 Kw (radiator conversion)
3Kw 130 VDC Dynamo to be added. (compressor + hyd pump)
Original Lister D, megasquirt multifuel project, compressor and truck alternator.
Current status - project / standby, Fuel, good old pump diesel.

Procrustes

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Re: seeking an answer...
« Reply #11 on: November 15, 2006, 03:41:55 AM »
interestingly i can find formulae for every facet of an engine, from volumetric efficiency to mach index's, from cylinder pressures to flame propagation and ignition timeing, connecting rod ratio's to chamber design, 1st, 2nd, 3rd, etc harmonics to resilient mounts, literally every part and parcel of an engine can and has been analized and expressed in some form of formulae, .... save one!

I'm not addressing your main argument one way or the other Bob, but I don't think this particular part is true.  If it were, there would be no need to experiment with engines as one could predict the results of a given change.

mobile_bob

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Re: seeking an answer...
« Reply #12 on: November 15, 2006, 07:39:15 AM »
Guy:

"you say I am misdirecting you with talk of the moon constantly accelerating but never changing speed, I am not, I'm trying to show you with another example because you appear to be dead set against seeing the answer being laid before you."


perhaps your conclusion that i am dead set against seeing the answer, is based on either you being dead set against answering my question or more likely i am not clear in defining my question.

for now i will assume i am at fault in not defining or relating my question in specific terms.

let me preface my question

i can find math and formulae to determine optimum cam profiles, valve opening, diameters, runner lengths etc.

i can find math and formulae to determine optimum bore to stroke ratio's, con rod ratio's etc

i can find math and formulae to determine proper dimensions and materials for every component of an engine

i can find math and formulae for things as basic as the motor mounting bolts, grade, diameter, thread pitch etc.

i can find very complex math and formulae for determining vibration, harmonics of ever order

i can find math and formulae from the most simple fastener to the most complex theoretical for each and every part of the engine proper.

but not one digit of math or formulae on design considerations of a concrete base?

am i to believe that the math/formulae  for the concrete base is so simplistic so as not to merit mention anywhere? or...

so complex that mear mortals cannot conceptualize, or compute it, so this is why there is no reference to it? or....

something in between that just happened to slip through the cracks, everyone forgot to make mention of the math/formulae?

is it something that is so carefully guarded that i would have to be killed if i was to be shown the math/formulae?

comeon Guy, seriously now....

there is no way that an engineer faced with having to determine the proper sizing of a concrete base would have to go thru some planetary analysis to come to
the design criteria.

there simply has to be a more direct route or set of variables that can be plugged into a formulae to determine the proper dimensions
variables such as

rpm, 4 stroke/2stroke, weights, physical dimensions of the engine, crank center height, mounting dimensions to name a few

you would have to know all these a many more even if you were to work thru some planetary formulae and then adapt that result to your application.

this is a big bone to swallow on blind faith,

now if i could find some text or mention of formulae that said some version of:

(rpm/ weight * center height )/ the square root of blah blah blah, the result of which is X

then plug X into the second formulae where base length is .761*X/ ou812,, blah blah blah

i hope you see where i am going with this?

if (and i still say if), the concrete base was engineered then there should be some reference to the use of math/ formulae somewhere

i don't have to do obscure math to figure every other part of the engine, there are clear and concise formulae for each part
i dont have to track the path of one of pluto's moons to determine optimum injection timing, valve sizing etc

why do i have to do obscure math for the concrete base?

is the concrete base a "black" art and not science or math

do i need an astrologer? i witch doctor?

where is the friggin beef?

specifically and very narrowly stated

"WHERE IS THE FORMULAE FOR DETERMINING THE PROPER DIMENSIONS OF A CONCRETE BASE FOR A GIVEN ENGINE"

BOB G
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GuyFawkes

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Re: seeking an answer...
« Reply #13 on: November 15, 2006, 11:48:29 AM »
I said I wasn't going to answer this question any more, but I am, for two reasons.

1/ I have to sit here and wait for someone to turn up so I am bored.

2/ It may be that the root of this problem is one of simple communication.

Go look at http://faculty.ifmo.ru/butikov/Projects/Collection4.html (you have to enable java etc)

Both views show the same thing, one from the centre of mass, one from one body as the centre.

You cannot "see" centre of mass, so you will always, via common sense, see the lower view, which is technically incorrect.

so, to your question, again.

You go and calculate the various vectors and forces acting on your lister cs, newtons second law f=ma etc etc etc etc.

You look at this result from the point of view of the top animation above, not the common sense lower animation.

You will see that many of the forces generated are acting within the radius of the crank, which is not good.

You know from your calculations that all you have to do to alter these various vectors and forces and move them too is alter the centre of mass of the whole shebang.

Easiest way to alter the centre of mass of the whole shebang is add mass externally, easiest way to consistently do that is add concrete.

Your calculations will tell you how much mass you need to add, how far it needs to be from crankshaft axis, and at what bearing.

Factor in density of concrete (or depleted uranium, or lead, or cast iron, or any other suitable material) and you will get dimensions.

========================

The moon is CONSTANTLY ACCELERATING, yet, apparently paradoxically, the moon is travelling at a CONSTANT VELOCITY in its orbit.

If you do not GET this, if you do not GET that acceleration is rate of change of velocity in a given direction, etc you have NOT worked with the math and done force vectors to velocity vectors to acceleration vectors to etc etc etc.

If you have not ever actually done the math you will not ever actually understand the answer.

==========================

ONLY BASIC MATH works like a simple spreadsheet, punch in a few numbers and get an answer out, numbers that make sense.... if it takes ten men working eight hours a day three days to dig a trench six feet deep and three feet wide and sixty feet long how long does it take five men to dig a hole ten feet in diameter and ten feet deep.

this is BASIC MATH.

Ask Mr Belk about ballistics, if you want to hit a target 6000 yards away with an intervening building 300 feet high with a projectile weighing 4 pounds there is only one solution for a given muzzle velocity.

this is NOT BASIC MATH

There are two sorts of people who will actually hit that target in practice.
The ones is forty years of experience.
The ones with ballistic computers, not spreadsheets, ballistic computers.

You are making some FUNDAMENTAL errors here.

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i can find math and formulae to determine optimum cam profiles, valve opening, diameters, runner lengths etc.

sure you can, except when you try and use them from base data with real world examples you will NEVER as long as you have a hole in your ass come up with a cam profile that is actually fitted to your sample engine, or valve lift, duration, etc etc.


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i can find math and formulae to determine optimum bore to stroke ratio's, con rod ratio's etc

sure you can, if you first ignore reality and define some arbitrary optimum which is anything but....
go on, stick a lister CS into your formulae and see what you get

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i can find math and formulae to determine proper dimensions and materials for every component of an engine
sure you can, as long as you dont actually try and build an engine from that data and that data ONLY and do not do anything except stop dead the instant you find a bit of data not produced by your calculations, which in reality will stop you before you even start making the mould to pour the first billet before you even think about machining to size

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Bob, here is a challenge for you. It will take you some time, but it used to be a basic apprentice task.

Get yourself a lump of nearly pure copper at least 1.2 inches in x , y, z dimensions.

You will of course be able to calculate exactly the mass of a perfect one inch cube of this material, and of course you will be able to calculate perfectly the volume.

Using a vice and a file, for nothing else is needed, transform this lump of copper into a perfect one inch cube, accurate to less than 2 thou, it will take you some time, perhaps a full day.

A micrometer will tell you if all three opposing sides are parallel and between 0.998 and 1.002 inches.
A machinists square and silk thread will tell you if it is square.
A displacement flask will tell you if it is between 0.994 and 1.006 cubic inches in volume.

You are not a young apprentice, so it should not take you a week and 5 or 6 wasted pieces of work before you "get" how to do it. You should be able to do it first time in a single day.

WHEN you have done this, you will understand the materials properties of copper in ways that didn't even register on the radar today, even though you almost certainly think you know "enough" about copper.

The MATH is the same, you THINK you understand enough about it because you have found a few forumula of basic math that you think makes sense to you and give you sensible results, even though you have not compared any of them to real world results.

Do you MATH apprenticeship in the same way and the same understanding will dawn, there is no shortcut.

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many years ago I released a freeware marine propeller calculator for displacement hulls based on a spreadsheet, with the various things spread over different pages of the sheet so people could follow the working and learn and not bug me with questions.

I created it after many years in the industry and checked it with a real world sample of three figures (eg hundreds) of actual boats where I knew the data for a fact, the results, as it said, were suprisingly good, but almost never matched what was actually fitted, because I was using all the correct formulae, which neatly omits some tupperware yacht builder wanting to fit a tiny engine to maximise internal cabin volume and a tiny propeller to minimise drag while sailing.

follow the formulae and you can always get off a lee shore, and make hull speed in most seas too.

nobody in recreation boat land follows the formulae

deep sea fishing boats, admiralty pinnaces, things like that match it excellently.

so an analogy of what we have here is a hobby sailor (you) saying you think the trawler hull was never designed to be a part of the engine bed, and until and unless the shipyards who have been building trawlers for generations can show you why you shouldn't use glassed in softwood beams and isolastic mounts to put a trawler engine in your flexible lightweight tupperware hull you ain't buying it, so they point you towards wake factor, block coefficient, analysis pitch, modulus of elasticity of the shaft, and you still claim it ain't a good enough answer.

it IS a good enough answer for THEM, and THEY build trawlers, YOU don't.

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you can put your trawler engine in your tupperware boat, and probably not sink or kill yourself, because you won't be going deep sea fishing

that does NOT make you right and them wrong.

if you try and go deep sea fishing you will, sooner or later, sink and kill yourself

Be honest.

Almost none of you have any requirement for 100,000+ hours major service intervals, a 10,000 hour engine will do you.

LISTER WOULD NO MORE BE IN YOUR BUDGET THAN ARROW IS TODAY.

If you want to do it right do it the lister way and bolt that fucker solid to a big block (not slab) of concrete.

If you want to understand why that is right then sit down and study the math for a few weeks or months and learn it.

there are no other options. there are no shortcuts.

I don't know if mr belk is a seat of the pants gunsmith or if he knows all the math too, it doesn't make any difference, I can learn all the math within a year, and he could still lose me for dead within 60 seconds of starting work, and consider me bloody dangerous within 5 minutes, there are no shortcuts.

studying the math for a year will do one thing and one thing only, it will allow me to understand what he is saying when he says that this part of this gun needs to made just so, there are no shortcuts.

people who are not prepared to study the math and do the apprenticeship have two option, pop into guns-r-us and buy a ruger blackhawk in 44 mag because dirty harry had one and dirty harry is cool, or go to jack with a wad of cash and tell him what sort of shooting they want to do, and end up with a gun for life.

Lister were the same, same thing applies.

there are no shortcuts

now I really am done answering this question.

(until and unless someone demonstrates that they have learned and done the math and then ask a question based upon that)
--
Original Lister CS 6/1 Start-o-matic 2.5 Kw (radiator conversion)
3Kw 130 VDC Dynamo to be added. (compressor + hyd pump)
Original Lister D, megasquirt multifuel project, compressor and truck alternator.
Current status - project / standby, Fuel, good old pump diesel.

Andre Blanchard

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Re: seeking an answer...
« Reply #14 on: November 15, 2006, 06:48:29 PM »
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The moon is CONSTANTLY ACCELERATING, yet, apparently paradoxically, the moon is travelling at a CONSTANT VELOCITY in its orbit.

If you do not GET this, if you do not GET that acceleration is rate of change of velocity in a given direction, etc you have NOT worked with the math and done force vectors to velocity vectors to acceleration vectors to etc etc etc.

If you have not ever actually done the math you will not ever actually understand the answer.

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Getting a little sloppy with the word "velocity" there Guy.
I know you know this but for those who skipped intro science class.

Velocity is one of those words that is very commonly used carelessly, and so has become synonymous with the word speed when used by the general population.

However when you are talking celestial mechanics velocity is a vector (it includes both speed and direction) and speed is scalar (no direction) so the velocity of the moon is always changing but the speed component of the vector is constant (assuming a perfectly circular orbit or limited resolution).
http://whatis.techtarget.com/definition/0,,sid9_gci755044,00.html

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Using a vice and a file, for nothing else is needed, transform this lump of copper into a perfect one inch cube, accurate to less than 2 thou, it will take you some time, perhaps a full day.

A micrometer will tell you if all three opposing sides are parallel and between 0.998 and 1.002 inches.
A machinists square and silk thread will tell you if it is square.
A displacement flask will tell you if it is between 0.994 and 1.006 cubic inches in volume.
Don't need the square, and the displacement flask should just be a sanity check on your measurements and calculations.

1. Use the three surfaces method to get one truly flat surface to start with.
2. File the opposite surface parallel with the first.
3. Repeat for the second set of parallel surfaces, eye balling it square and making the distance a little big.
4. You can now use the mic. to measure across the edges and work the second set into square and to size with the first.
5. Repeat for the third set of surfaces but make square with both the first and second set.

You will need a very light touch to keep from squishing flats on the edges with the mic..





There has been mention of the great personalities of science and engineering.  What made these people great is not raw intelligence or the willingness to look at things differently then what is commonly known, both are fairly common by themselves, but the combination is not, also need a good deal of luck.  If certain people in Watt's early life would have died he could have easily been just another name lost in the mists of time.  And someone else or combination of others would have stepped in a made virtually the same contributions in almost the same time frame, there were a lot of people working on the problem at that time as seen by the number of patent lawsuits, Watt was in on a number of them and from both sides.

A little on Newton I found interesting.
In 1936 John Keynes purchased a cache of Newton's writings that the Royal Society had said were of no scientific value.  After reading thru the notebooks Keynes said in a lecture to the Royal Society club that Newton was not the first of the age of reason, but the last of the magicians.
Research Newton with respect to religion and alchemy.

« Last Edit: November 15, 2006, 06:50:27 PM by Andre Blanchard »
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Andre' B