"Rod McInnis" wrote in message ...
"basskisser" wrote in message
om...

The torsional forces can not have any effect on the trailer balace as
long
as the wheels are round or allowed to rotate.

Bull****. Are you telling me that if you have a moment arm, and apply
a torsional spring constant to it, that it won't try to rotate about
the axis of the axle????????

Nope. If the wheel is free to rotate (which it will be unless the brakes
are applied AND the wheel is somehow contrained from rotating) then there
will be no moment about the axel.

Really? Have you thought about the fact that the wheel is NOT "free to
rotate"? There is drag from the bearings, and the tire is not round,
the contact patch is virtually flat, affecting the outcome even more.

There will be a moment about the torsion bar, which is NOT the axle .

If that is true, then a torsion spring,
and it's ensuing torsional constant, aren't doing any work.

Correct! Any engineer would be able to tell you that the forces exerted by
a spring (including a torsion bar) do no work when they are at a steady
state condition. A spring will store "potential" energy. While it is
holding that engery it does no work. Work requires a force applied over a
distance. Just an applied force does no work.

so you are trying to say that all will be fine with your analysis up
to the point where a load is applied, and or the trailer is moved,
correct? I think I want to measure MY trailer's performance under
actual conditions. I could care less about it's performance when
parked, except for it's abiltity to resist the forces of the boat, and
wind, snow, etc. loads.


Duh.....that's why I asked...geez... AND, how do you know WHERE that
center of MASS will be?

Well, geeze, he said very clearly that he put the boat on the trailer
(actually, he said he put the trailer under the boat) such that the boat was
sitting on the trailer as it was expected to be.

Very clearly said that? That's odd, here is the original post:
So the axels that we have are torsion axels (no springs). They will
just
attach
directly to the underside of our trailer. The thing is, it's not just
a
straight
across axel. Well, the axel goes straight across, but coming from the
center of the axel is a 6" arm that goes back to the spindle. In
other
words,
the tires are off-set 6" behind where the axel is.

For a picture go to this web sire (really an Adobe PDF document)
and see page 5 (the 2,300 lb to 3,500 lb Torflex axel).
http://www.redneck-trailer.com/pdf/A/810torflex.pdf


PUZZLER: Does the axel "balance" the weight over the
axel or over the wheels? .

Put another way: Say we had a rectangular frame 20 feel long and
it was perfectly balanced at the 10 point. (No boat or anything on
it yet.) So a straight across axel put at the 10' point, it'd
basically
balance. But with our axels, where the wheels are off-set 6"....do
we put the AXEL at that 10' point or do we have the
WHEELS at that 10' point.

Our current thinking is that it's the wheels. It's pretty hard to
test
because of the weights involved and we have to weld the axels on
(not bolt 'em) so we'ld like to get it right the first time.


Thus, any measurements he
takes will be for the boat + trailer. What each one individually is doesn't
matter for the purpose of this discussion.

So, now you want to talk about center of mass as opposed to center of
gravity?

Nope. On level ground and constant velocity it doesn't matter. To expand
the discussion to include an "accelerated frame of reference" is a lot more
work.

My point is, he didn't mention the relationship between the center of
mass of the boat, and the center of mass of the trailer.

Which is totally irrellavent. He only needs to be concerned about the two
together, which he has taken care of by putting the two together when he
made his measurments.

Wrong, again, please read the above ORIGINAL post.

What is YOUR point? I notice you've not interjected one thing to help.

My point is that some of your comments are false and do nothing but confuse
the issue.

Nah, that's YOU!