1998 Grand Caravan

So you claim to know most of the engineers in the world, or just most of
them in your little world?

I've known 11 personally and 6 of those couldn't pour water out of a boot
with directions on the heel.

--
Budd Cochran

John 3:16-17, Ephesians 2:8-9

"Our Constitution was made only for a moral and religious people.
It is wholly inadequate for the government of any other."
(John Adams)

 

Uhh - to you maybe, but everyone else considers it atrocious (oh - sorry
- that's a word that means 'bad'). Or are you just trying to play
another shell game with words (morphing the word 'accepted' into
'acceptable')?

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

So are you going to apply the same analysis to everyone who works as a
mechanic? Hate to tell you, but the ratios of bad mechanics are a lot
worse. Let's start with WalMart, Jiffie Lube, independent shops, dealer
shops, shops in the back of NAPA stores, etc., etc., etc. - you've gotta
throw all those into the mix - i.e., you can't skew the results by
eliminating certain categories first before you apply the analysis.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Hi Bill...

Find it terrible terrible hard to believe

That's an incredible amount of heat to get rid of; stand well
back before the whole thing melts!

Take care.

Ken

 

Hi...

About twenty years ago had 4 dealership mechanics. Defining
mechanics all these four were well experienced, all worked
together in the same dealership, and at *least* one was fully
licensed. (worked on brakes, steering, etc)

They told me, argued with me, that they had found the cure of
all energy problems. All they needed to do was attach an electric
motor to each wheel, and an alternator to each wheel. Start it
going with the gas engine and from then on it would keep going
"forever".

They were dead serious. Sent in one of those rip-off applications
to one of the USA patent companies, who told them their idea was
wonderful, and to send their cheque for further investigation.
They sent their cheque. Nothing would convince them not to

Ken

 

Your argument isn't very convincing in that, in your lever examples, you
appear to be equating force and mechanical advantage with energy loss,
and that just isn't inherently the case (the same being true with gear
ratios, which I know you correctly related to levers). The energy loss
(heat generated) has nothing to do with the mechanical advantage (the
distance/force trade-offs) but has everything to do with the friction in
the transfer of motion - nothing to do with the lengths of the levers
(size of the gears), and everything to do with the reduction of friction
at the points of sliding, pivoting, etc.

No offense, but this is exactly the kind of technically incorrect
discussion that seems to crop up with those who consider themselves
technically savvy in a *hands-on* sense but who put down those with
technical (in a *theoretical* sense) expertise. In the same way that
you would correctly invoke Archimedes, I would say "Yes, but you also
need to consider the law of the conservation of energy which you seem to
be ignoring (in your lever examples)". You could move the world with
Archimede's lever, but not very rapidly. You could use an opposite
lever to move a pea and move it very rapidly. The energy put into the
system to accomplish both may be the same - one has a lot of mass moving
very slowly, the other has a tiny mass moving very rapidly - the energy
calculations are the same - energy applied minus friction losses =
energy out.

Now - one implementation of the gears or levers may be more efficient
than the other, but it's all in how the friction losses are managed, and
not in the mechanical advantage per-se.

There's a place for both "hands on" and "theroetical" - and results are
best when they co-exist. Real world follows the laws of physics - what
some here disdainfully call "theoretical"; but what many are
sarcastically or disdainfully calling the "theoretical" *is/are* the
real world laws of physics.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Yep - just like a week or so ago someone here claiming that an
alternator with a working regulator would provide fully regulated
voltage no matter what - another perpetual motion machine.

These are the same guys who will out of hand reject engineers for
spouting their laws of physics.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

You're right. It has been proposed by some that the "losses" are not
real, and are purely a result of the manufacturer's overstated engine
output blindly plugged into the efficiency equations with the
dynamometer-measured horsepower at the wheels. On the other hand, maybe
that's why the ATF properties are so critical.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Yep - just like a week or so ago someone here claiming that an alternator

Thats another lie. But keep going, I'm beginning to to see a pattern here.
The context was "at any RPM", which when speaking of an automobile is
anything from idle on up, and nothing below. But of course instead of using
facts, you and others stretched things out of context. Nothing new there.

I don't "out of hand reject engineers", I reject those that won't follow
good diagnostic method, rely on something other than facts to "prove"
themselves correct, and generally lack the basic sense to realize that while
they are rejecting proven method, they are describing how they would take
six extra steps to find the same info the proven method would reveal.


--
Max

"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)

 

I wonder where they got the 33% loss figure. Frankly, that sounds like
BS to me. If the transmission really is dissipating 1/3 of the engine
power input as heat, then you'd need a transmission cooler bigger than
the radiator to cool it when running the car hard at all.

Matt

 

Methinks you are making the common confusion between power and force
(torque). A lever multiplies or divides force (or torque), but it
doesn't multiply or divide work or power.

You are the one proposing a violation of the laws of physics. Look up
the definition of work and then apply it to both ends of your lever and
report back your results.


Matt

 

Thats acceptable?

Once again, an engineer talking down to someone, knowing nothing of the
other persons credentials... and you wonder why we "common folk" get tired
of your crap.

I don't consider it acceptable. In fact, despite my dedicated following of
Chrysler, I would never buy something with an A604/41TE etc in it.

Will you next be defining "is"? I ask because you seem to think "accepted"
and "acceptable" are terribly different. If you choose to do so, make it
succinct (that means 'cut the bullshit out and get to the point')

--
Max

"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)

 

The gear ratio has virtually nothing to do with it.

Sure, more gears will consume power due to the frictional losses, but
this has little to do with the ratios. If you want to change the
overall ratio by 6:1, it doesn't matter if you do 3:1 first and then 2:1
or 2:1 followed by 3:1.


Matt

 

Nope, never made any such claim nor did Bill. Read again what he wrote,
more slowly this time, and see if you can figure out what he said.

You must hang around with a bunch of ignorant people then. I know a
couple hundred or more personally (I manager a group with nearly 40) and
I don't think 5 of the ones I know could be categorized as you suggest.


Matt

 

Mechanic he calls me..LOL...

No....Im just a low life could have been mech e that instead of sticking
with MBB.....thats an aircraft firm you now call AirBus BTW, or sticking
with the familys business...(thats a Dodge dealership on dads side, and some
higher ups with Chrysler over the years on moms) just owns a fairly busy
HVAC outfit thats going commercial, and knows what damn idiots most
overschooled engineers can be...
Of course, you assume as well that I just walked in here..and you cant be
farther from the truth...but its ok...its normal for you to assume as thats
the way you are taught.

 

Transmissions 101

Frictional losses are a given in ANY transmission design, as are heat
losses and parasitic losses. So, why mention the obvious that, as an
engineer, you should know about already?

In an overdrive ratio, do you have more or less usable torque on the
output shaft of the gearset? Energy ( torque in), divided ( OD,
remember?) by the ratio equals output torque ( minus parasitic losses,
of course!!!!) proportionally reduced according to the leverage . . er,
ratio of the gearset.

Sorry, it seems I stepped on a toe or two . . .

You assume they are ignored because they are unmetioned. Name a
transmission design that generates no friction, heat or parasitic
losses????? Now, since there is no such thing, these losses are common
and may be set asiode for a discussion of RATIOS AND THEIR EFFICIENCY.

True, I don't deny that and I didn't deny it. It was a metaphor.

Yaes, as in a trebuchet, for example ... nope, I didn't deny this
either, bith both of your exaples are fine evdence of the effectiveness
of RATIOS dependent, of course, on whether you want to lift a
locomotive or throw rocks.

Gear ratios parallel that law.

Agreed, but why are you adding given and common known factors into a
discussion on the effectiveness of RATIOS if not to cloud the topic to
save your butt?

ROTFLMBO!!!!!!!!!!!

Assume a 20% loss in either transmission to parasitical loss for sake
of discussion:

A 1:1 direct drive with a 100 ft.lb. input torque has 80
ft.lb.available from the output shaft out of a theoretical maximum of
100 ft.lb.

A 1:2 overdrive with a 100 ft.lb. input torque has only 40 ft.lb. left
out of a theoretical maximum of 50 ft.lb. (This is still theoretical
because it doesn't allow for the increased torque loss due to poor
mechanical advantage)

Now, tell us again which has the best torque output to run 75 mph with?

Math is "real life", Bill. 1+1=2 And as long as math is a true science
it can prove physics.

Budd

 

Matt,

I am not confusing the two. I am discussing the EFFICIENCY OF OD RATIOS
IN REAL WORLD SCENARIOS in regards to input torque and output torque.

OTOH, I believe you are trying to confuse the discussion.

Budd

 

Independent shops are often the best source for "outside the box"
repairs for items that, according to engineers, can't be repaired. I've
done it few times myself.

Now, I can agree readily that I don't consider MOST of the technician
staff in Wal-Mart, Jiffy Lube, et al, to be skilled mechanics. Many
were hired off the street, I'm sure.

I've never dealt with a NAPA shop except to have brake rotors and drums
turned and they older gentleman did an excellent job.

As for dealer shops . . .I've worked in one dealership and only one
mechanic in that dealership, the head mechanic, was worth his salt.
Btw, no, I was not working there as a mechanic, fyi.

So, yes, certain "categories" can be excluded as they are not trained
or experienced mechanics.

Now, should we include medical equipment engineers? Railroad engineers?
Ships engineers? Combat Engineers? Hey, all are "engineeers", aren't
they?

Budd

 

Excuse me, but have the laws of physics been repealed?

(btw, I've only added the parasitic back in because you guys were in tears
over their absence.)

If you cut available torque by 2/3+ (frictional losses too) then try to
multiply it back by doubling (minus frictional losses) you've got : ((x *
..66)*2)- 2FL. OTOH, (x/6)-FL saves a power loss because one less power
robbing loss is avoided.

And the other situation is just as bad.


--
Budd Cochran

John 3:16-17, Ephesians 2:8-9

"Our Constitution was made only for a moral and religious people.
It is wholly inadequate for the government of any other."
(John Adams)

 

I'm sorry, didn't mean to speak over your head. It was a reply to the
implication of the supposed superiority of the overly educated over that of
lowly high school graduates.

Oh, and it was as sarcastic as it reads.

Well, let's see. . . they were the engineers for an automotive muffler
factory and one of them came out of his air conditioned office, measured and
took notes on a machine built by a member of the millwright crew,, then went
in his office, drew up a set of blueprints and took full credit ( and the
monetary bonus) for the machine. two weeks later, he ordered extra steel
added which took the machine outside design parametres and nearly made it
useless.

The rest of what you called "ignorant" were good ol' boys from KY and TN
that simply lacked a high school education . . but they weren't stupid.

Send me an email to remind impressed with this later, OK?

Gee whiz, I'll just bet there ain't a single automotive engineering major in
the lot of them. And if there is, he's not employed in tha automotive
industry. . . .and that makes me wonder "why?"


--
Budd Cochran

John 3:16-17, Ephesians 2:8-9

"Our Constitution was made only for a moral and religious people.
It is wholly inadequate for the government of any other."
(John Adams)