On 3/29/2010 1:50 PM, John Cochrane wrote:


Well, even the fiberglass top can leak a little. When I put my plane
together the other day
there was a string of mud spots on the leading edge of my wings near
the root end. Those
parts of my wings are under the passive vents installed in the
trailer, so I'm getting some
moisture in through or around those vents.

-- Matt

This might also come from the even worse problem of metal-top (all)
trailers -- condensation.

Any day the 5 am temperature goes below the dewpoint (most days in the
spring), the glider inside the trailer will be sopping wet. It dries
out by noon if you have a good vent. But your beloved glider is
spending 4-5 hours a day covered in water.

I've attacked this successfully with a dehumidifier, but that needs
power which we don't have at my current airport.

The new insulated tops might help. Has anyone noticed a big
difference?

John Cochrane


If the 5 am air temperature goes below the dewpoint, you will have fog.
If your trailer is well ventilated (has a fan), you may get air inside
the trailer that is below the dew point. I wouldn't think an insulated
top would help. If the trailer is not well ventilated, however, it
would seem that an insulated top would help get the air inside the
trailer warmer than the dew point, and thus would help keep it dry.

Compare this situation with radiation of heat to space at night. If you
leave your glider tied out at night, it radiates heat, the fiberglass
can get below the dew point, and you can have water on the glider in the
morning. The same thing can happen to a metal trailer -- if the metal
ends up below the dew point, there will be water on the metal (both
inside and out). An insulated top should help here, because there is no
exposed metal inside the trailer.

This raises another question -- should trailers have fans? My aluminum
Cobra does not, and it (and the glider) always has been dry inside.