Ah, Guy_F - sometimes the simplest things(?) elude me.
I am aware of young's modulus. You don't need it often when you majored in optics unfortunately. Neither do you have to understand crankshaft flex in a 90-year old engine design that's being mounted in such a fashion that there is no 'fixed' point in it.
The old adage is, "on the internet, no-one knows you're a dog". So until someone can give me a hard answer, with numbers and pretty vector diagrams (preferably) so that I can follow the same steps and reach the same conclusion, all claims of "it's perfectly obvious" are moot. If it's obvious, one should be able to explain it in a few lines of text. So is it?
With the brief clarity of a cup of tea this morning, what I am thinking is that, say, with a rigid bearing between flywheel and crankshaft, any forces on either end will have a bending moment around the immobile bearing. Allow that bearing to move in the direction of the force a little and the forces at the other end of the now moveable pivot are altered. Everything still flexes, just where and how much is the question here, is it not?,
Can you do the math Guy_F? I've posted this question about crankshaft forces before up in the thread and I'll throw it out to the crowd again. Can anyone explain fully?
If you can, then set it out and let us (well, me) know once and for all. If you can't .... then at least we've still got heated words to back up our arguments,eh?
Funny how you can get a degree in optics and never encounter a lens being deformed by the shock loading of transmission of laser pulses. Youngs is the rate of change of stress with strain, and in optics is VERY commonly used as the operating principle of polariscopes, polarimiters, etc.
It's not even my field, but I know this. Strange.
Can I do the math (for an engine), you ask. Yes I can.
I've just spent about 3 hours tonight lecturing a (very promising) student.
People come in two flavours, those that prefer to be able to ask a question and get an answer, and those that prefer to to learn. The latter are in the minority.
The easy way to differentiate between them are the book learners and the thinkers. Book learners are always quick to do things like reach for spreadsheets and start banging made up (as opposed to tabulated from instruments over time) numbers into the first formula they found that appears to fit the bill.
Thinkers know everything that ever was and ever will be is subject to change, and sometimes some of those changes will be unexpected. A book learner will tell you he has calculated that slings and chains and load gives a safety factor of seven, a thinker will still arrange things so there is a safety sling and make sure nobody is standing in the path of anything, including the slings. A friend of mine lost his head, literally, when a hawser with a safety factor of about six parted, three other were hospitalised with serious injuries, the only one who walked away unscathed was a thinker, a canadian logger, who ducked for the cover he made damn sure he was standing next to the instant he saw the moisture being wrung out of the hawser.
Of course, if the book learners had KNOWN that the magnetic resonance (hall effect) testing of the wire rope was giving erroneous results because nobody included the effects of the big welder on the instrument head they might have calculated a different safety factor, and if the book learners had bothered to figure the rapid temperature rise from frozen on the drum to being played out under full tension they might have lowered it a bit more, and if the book learners had known that they had used the wrong equation (or rather, left out two important ones from the over all calculation) they might have lowered it a bit more.
Inquests suck. Misadventure my ass.
That wasn't the first, or the last, time in my life I have said out loud to other people "These assholes are going to kill someone one day" and lived to be proven right, me, I'm too small to stop it, I shouted, I've blown whistles, I've threatened to quit, I've quit, it never makes any difference because the one thing that is never in short supply is some asshole with book learning who is ready to sign off on it.
I've had pressure, deadlines and downtime and seriously big bucks for every hour that shit wasn't up, but money and metal can always be replaced, kill someone and you have had all they ever were and ever will be and nothing you ever do will dent that.
Only difference big bucks at stake makes is there is enough in the kitty for blone bints with big tits and an open bat tab to schmooze the PR machine when it all goes wrong.
You got a spreadsheet for taking a mans hand off so he never works again? What does that work out at in dollars?
I know you got fancy tables for risk assesment, that's what they are called anyway, but the purpose isn't to mitigate risk, it is to wash your hands when the numbers come up, hey, we did a risk assessment, so we ain't culpable.
Kipling said "when arf your bullets fly wide in the ditch", things ain't changed
The Young British Soldier
When the 'arf-made recruity goes out to the East
'E acts like a babe an' 'e drinks like a beast,
An' 'e wonders because 'e is frequent deceased
Ere 'e's fit for to serve as a soldier.
Serve, serve, serve as a soldier,
Serve, serve, serve as a soldier,
Serve, serve, serve as a soldier,
So-oldier OF the Queen!
Now all you recruities what's drafted to-day,
You shut up your rag-box an' 'ark to my lay,
An' I'll sing you a soldier as far as I may:
A soldier what's fit for a soldier.
Fit, fit, fit for a soldier . . .
First mind you steer clear o' the grog-sellers' huts,
For they sell you Fixed Bay'nets that rots out your guts --
Ay, drink that 'ud eat the live steel from your butts --
An' it's bad for the young British soldier.
Bad, bad, bad for the soldier . . .
When the cholera comes -- as it will past a doubt --
Keep out of the wet and don't go on the shout,
For the sickness gets in as the liquor dies out,
An' it crumples the young British soldier.
Crum-, crum-, crumples the soldier . . .
But the worst o' your foes is the sun over'ead:
You must wear your 'elmet for all that is said:
If 'e finds you uncovered 'e'll knock you down dead,
An' you'll die like a fool of a soldier.
Fool, fool, fool of a soldier . . .
If you're cast for fatigue by a sergeant unkind,
Don't grouse like a woman nor crack on nor blind;
Be handy and civil, and then you will find
That it's beer for the young British soldier.
Beer, beer, beer for the soldier . . .
Now, if you must marry, take care she is old --
A troop-sergeant's widow's the nicest I'm told,
For beauty won't help if your rations is cold,
Nor love ain't enough for a soldier.
'Nough, 'nough, 'nough for a soldier . . .
If the wife should go wrong with a comrade, be loath
To shoot when you catch 'em -- you'll swing, on my oath! --
Make 'im take 'er and keep 'er: that's Hell for them both,
An' you're shut o' the curse of a soldier.
Curse, curse, curse of a soldier . . .
When first under fire an' you're wishful to duck,
Don't look nor take 'eed at the man that is struck,
Be thankful you're livin', and trust to your luck
And march to your front like a soldier.
Front, front, front like a soldier . . .
When 'arf of your bullets fly wide in the ditch,
Don't call your Martini a cross-eyed old bitch;
She's human as you are -- you treat her as sich,
An' she'll fight for the young British soldier.
Fight, fight, fight for the soldier . . .
When shakin' their bustles like ladies so fine,
The guns o' the enemy wheel into line,
Shoot low at the limbers an' don't mind the shine,
For noise never startles the soldier.
Start-, start-, startles the soldier . . .
If your officer's dead and the sergeants look white,
Remember it's ruin to run from a fight:
So take open order, lie down, and sit tight,
And wait for supports like a soldier.
Wait, wait, wait like a soldier . . .
When you're wounded and left on Afghanistan's plains,
And the women come out to cut up what remains,
Jest roll to your rifle and blow out your brains
An' go to your Gawd like a soldier.
Go, go, go like a soldier,
Go, go, go like a soldier,
Go, go, go like a soldier,
So-oldier OF the Queen!