Cumberland Camper Story 2 - Tent Design

The design of the Cumberland's tent had to fit within an envelope of requirements.

• Provide as much living volume as possible for 4 people to sleep and sit in comfort.

• Be weather resistant - which means that it had to shed wind and rain. So, it had also to be durable and rugged.

• Be these things sitting on top of the unfolded trailer rather than staked to the ground, nor should it require guylines staked to the ground. Only the trailer tongue, tires and jacks contact the ground.

• We wanted the whole camper to look as much as possible as if it belongs in the outdoors rather than an intruder; that it is exactly where it belongs. It should have small impact on the ground and surroundings wherever it is used.

As with many designs, these requirements compete with each other. E.G., the tent can't be a large slab sided thing with a huge living volume and also present a small target to high winds. The unfolded trailer footprint dictates the footprint of the tent, and the size of the trailer is largely driven by the towing size and weight target with a primary requirement that the Cumberland tows small and light and lives large. The entire Cumberland design is a collection of trade-offs that seeks to provide the best value in terms of functionality, durability, performance, comfort, and cost.

Without dragging you through all the bumps, starts, and stops. The short story is that a modified dome with internal poles and awnings over the door and windows answered the need for a shape that was aerodynamically smooth, is relatively rigid, sheds rain, is open to the outside, and presents an interior with volume where it is needed for comfortable living.

We love it.

A design patent has been granted.

Patents for a number of the mechanical details are patented.

Whether to provide a cover or not was a question. The simplicity of a single layer tent is attractive. A 'canopy' material that is made to be water repellent (almost nothing is rated as water proof) is used for the tent dome and canopies, and the seams are sealed either with tape or a sealing solution depending on the seam. The tent has been used in the rain without a cover several times and the result is that the it will stay dry inside during a shower or two. We did our entire second field test without a cover.

During a prolonged rain, water will eventually find a path through almost any fabric. In the right circumstances, you will be able to do without, but the circumstances are not always right.

For the third field test, we had a very good cover that proved itself in what was a fairly rainy trip. But it was expensive and bulky. While searching for a better solution, we found an approach with a great side benefit. In short, when a radiant barrier is incorporated into the cover, the water repellency is improved and it also serves as an effective heat shield.

You may know what the inside of a ground tent is like under a hot sun. It gets hotter inside the tent than outside even with a fabric rain cover and the windows open. Heat radiates down from the top of the tent, it gets trapped inside and the tent becomes too hot to sit in. With the Cumberland's new cover in place, sitting inside the tent with the windows open is like sitting in the shade. Testing in the sun with and without the cover, the difference is both large and immediate. In the middle of a warm (88 degree) sunny day in the Oklahoma panhandle, heat radiating down through the top of the tent could be felt. The radiated heat was gone as soon as the new cover was in place and the temperature in the tent dropped over 10 degrees.

When it is cold outside, it works the other way. The radiant barrier reflects heat back into the tent. We included the new cover in our patent application.