Trailer Axel / Physics Puzzler
"basskisser" wrote in message
om...
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.
Well, up to now the discussion had been limited to the trailer sitting still
in the driveway, so rolling resistance wouldn't be a factor. Even so, the
drag from the bearings is so small that it can safely be ignored. The drag
of the brakes might be measurable, but the rolling resistance of the tire
(essentially the flexing of the sidewalls) will dwarf everything else. Even
so, I have never even heard of anyone even attempting to calculate or
measure what the rolling tongue weight would be in comparison to the
stationary tongue weight.
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 don't know how you made this leap. All the discussion has been with the
boat (the load) applied.
I think I want to measure MY trailer's performance under
actual conditions.
Loading the boat on the trailer and measuring the resulting tongue weight,
which is what Gary did, is about as close as you can come to measuring under
actual conditions, unless you want to go to the trouble of constructing a
strain gauge on your hitch to measure the forces as you travel down the
road.
I could care less about it's performance when
parked, except for it's ability to resist the forces of the boat, and
wind, snow, etc. loads.
So far, I have only commented on the tongue weight, and have made no
predictions about the "performance" of the trailer. Tongue weight is
generally considered to be a "static" problem. As I have said several
times, to analyze the trailer in an accelerated frame of reference is far
beyond anything that we have discussed. This would require knowledge of the
material strength of the trailer, the exact construction, and how boat and
trailer contact each other.
I have no idea if this trailer is going to sway or fishtail. This is a
dynamic problem. I can tell you what the tongue weight will be (except for
wind effects) while it is at a constant velocity. That is a statics
problem.
Very clearly said that? That's odd, here is the original post:
Yes, he very clearly said that the boat was sitting on the trailer. Why did
you quote his description of the axle? It has nothing to do with the
discussion of how the boat was sitting on the trailer when he measured the
tongue weight.
Perhaps you didn't follow the entire thread. Go back and read it from the
beginning. Look at the pictures that he provided. Read how he placed the
trailer under the boat, supported the entire rig on blocks and measured the
tongue weight. Examine the table he created where he moved the axles and
extended the tongue. Once you understand what the discussion is about, then
maybe you can offer an explanation as to why the tongue weight didn't change
much when he extended the length of the tongue. Or maybe you can't,
considering you making false claims back when we discussed this in theory a
couple of months ago.
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