Basic Questions

[Ed K.]

If all of your weight stays near the CG, you shouldn't have lateral shimmy problems.

Kenny,

I'm going to show my ignorance here but what is "CG"?

Thanks,
Ed

[madjack]

"CG"=center of gravity...which is what trailer balance is about...you ideally want 10-15% of total weight on the tongue and the rest on the axles for best distribution of weight...........
madjack

[kennyrayandersen]

Sorry about that -- I get carried away sometimes. When an Ice skater pulls their arms in then suddenly, they start spinning real fast and when they put their arms back out they again suddenly return to a much slower rate. That is because they are changing their rotational inertia (polar moment of inertia), or the effort required to spin something. The more mass something has, and the bigger that mass is results in a higher moment of inertia. For instance it’s easy to spin a small top, but it takes some effort to get a merry-go-round spun up.

This is important for travel trailers as the propensity to have oscillations and instability is a function mostly of speed and polar (rotational) moment of inertia. When you load everything near the CG, or rather most of the weight of the trailer is near the CG, which in fact is the case for most teardrop trailers, the trailer is easy to spin (it has a lower polar moment of inertia) and therefore easier to control. When the weight is further away from the CG location as in there is a lot of mass at the front and a lot of mass at the back, then you increase the polar moment of inertia (the trailer takes more effort to spin) and increase the likelihood that you will have stability problems, or have them at a lower speed.

Teardrops are pretty good for this usually as most of the mass is pretty close to the CG (the galley and other heavy items are pretty near the axles). Additionally, the distance from the CG to the ball and hitch is quite long by comparison, which give the car a lot of leverage on the trailer.

[Ed K.]

Wow Kenny, that's a mouth full!

I think I'll start a new thread about my build even though it's only in the planning stages at this point. Thanks for all of the help. Expect lots more questions.

Ed