Ballooning roof

That's called "roof tumor."

I have seen this often. But am wondering, is there anyway you can tell if it's happening to your trailer?

Rwebby wrote:
I have seen this often. But am wondering, is there anyway you can tell if it's happening to your trailer?

Stand on the roof of the 5'er and have your DW tow it down the highway at 55 MPH. You'll see it. Just watch out for overpasses.

I saw mine while operating a motorcycle in front of wife driving our rig. Upon inspection I would see the rubber roof was unglued and easily lifted in the front.

An RV tech told me the air to lift the roof comes from the hitch, up the fiberglass cap, and under the front metal strap. Sure enough, we found about only a few screws holding the metal strap down making it easy for air to pass through. Hard to believe we found shoddy workmanship, huh?

The RV Tech re-glued the rubber roof from the front and under the a/c. He said many will come loose back to the a/c. His work has held up for several years now. Unfortunately, the tech is no longer around.

A lot of times it's simply lift produced by the airflow over the front cap, same as a wing. Bernoulli's Principle, if you want to get technical. :-)

Lyle

laknox wrote:
A lot of times it's simply lift produced by the airflow over the front cap, same as a wing. Bernoulli's Principle, if you want to get technical. :-)

Lyle

This. It's not because air gets under it. It's because the air moving over the top of the roof is moving faster than the air under it. This creates a high pressure area under the membrane that results in "lift".

That was my concern. You might not know until it was too late.

Put vortex generators on the roof. Kill the lift.

Jerry B wrote:
Put vortex generators on the roof. Kill the lift.

Problem is that you'd be sticking them to the already loose rubber. :-)

Lyle

On aircraft, vortex generators are used to increase lift.