We’ve landed in Tucson, and thus the Airstream has returned to home base after seven months of travel.  It is now tucked away in its carport, getting a well deserved rest after a total voyage of nearly 9,000 towing miles. Likewise, the Mercedes is chillin’, with 14,800 new miles added to its odometer since we left in May.

There are a lot of ways I could measure this trip, but the photo at right shows my favorite. Emma has grown an inch and a quarter, as marked on the door jamb of our Airstream bedroom.  By any measure, it has been a good period of growth for all of us.

The last phase of our trip was unremarkable by design. We basically bolted 350 miles from Padre Island to central Texas, where we camped overnight at the Caverns of Sonora’s little campground (W/E, $15).  If you are driving through central Texas on I-10, there are few options for overnight stays, and many of them are of the down-and-out variety.  So Caverns of Sonora provides a very welcome oasis just about five miles off the highway.  The big attraction is of course the exceptionally well-decorated caverns, but Emma thought the peacocks that roam the campground were pretty worthy too.

Our next day was  another 350 miles, this time through west Texas and over to Las Cruces.  It was a stunningly beautiful fall day in west Texas, with azure blue skies and temperatures of around 78-80 degrees, but with one unfortunate aspect for towing: a strong headwind. Many times I am asked, “Does that Mercedes really pull that big trailer OK?” and the followup question is often “Well, how about in the mountains?” or “Yeah, but wait until you cross the Rockies!”  When people say such things I know that they aren’t really experienced at towing, because if they were they’d know that the true challenge of a tow vehicle is not the occasional mountain pass, but the long day spent bucking a 25-knot headwind.  That’s when you find out who has the chops.

See, you can almost always get up a hill one way or another.  You might have to go slower, or stop to let the engine cool off, but it’s very rare to find a hill so steep that you can’t climb it with any decent tow vehicle.  (We have never had an overheating problem with the Mercedes, but we did with the Nissan Armada. The Mercedes does high-elevation climbs much better, mostly because of the torquey turbodiesel, which isn’t affected by the thinner air at altitude.)  And hills are generally short.  In Colorado you can find a few 6-8% grades that run for eight miles, and in Wyoming there’s the Teton Pass at 10%, but that’s about as bad as it gets.

In contrast, imagine trying to pull a trailer through a strong headwind for 350 miles.   That’s a whole different ballgame.  If your tow vehicle struggles from lack of power, or your trailer is being tossed around by gusty winds, or if you’re not hitched up properly, you’ll feel that misery for six hours.  That makes a 20 minute hill climb in the Rockies look like a happy memory.

You’ll run into that a lot when heading west through the central states.  I-90 through South Dakota, I-80 through Nebraska, I-70 through Kansas, I-40 through Oklahoma and Texas, or I-10/20 through Texas.  We’ve hit it in all of those locations.  The car can do it, and our ride is safe & comfortable, but fuel economy suffers horribly.  Sometimes we just stop for the night and try again the next day.

Our headwind on I-10 was pretty stiff.  I know because our fuel economy plummeted, from 13.5 MPG the previous day to a dismal 10.3 MPG.  Keep in mind that your speed relative to the air (airspeed) is what matters to your fuel economy, not the weight or length of the trailer.  If you normally tow at 65 MPH in calm wind conditions, a 25-knot headwind results in drag equivalent to towing at 90 MPH.  Because air resistance (drag) increases in proportion to the square of your airspeed, a headwind like that has a massive impact.

In our case, the wind-induced penalty was about 30% of our fuel economy.  At one point we were getting just 9.7 MPG, the absolute worst I have ever seen from this vehicle.  But in west Texas, the options for stopping overnight are somewhat limited, and it didn’t look like the wind was going to abate much in the coming day.  So we plowed on.  By the time we reached the brutish traffic of El Paso, the wind had died down and it was relatively smooth sailing up to Las Cruces.

[By the way, the center display in the photo above deserves some explanation.  The display shows the distance and travel time since our last fuel stop (87 miles, 1 hour, 25 minutes), our average speed (61 MPH), our fuel economy average since last fuel stop (9.7, ugh), the outside air temp and the cruise control setting (65 MPH).  I normally tow a little slower but the speed limit was 80 MPH and I didn’t want to leave a huge differential between us and the rest of the NASCAR traffic.  The car tows very nicely in 7th gear at about 2200 RPM at that speed.]

After this expensive day of driving, we decided to cheap out and try parking at the Cracker Barrel again.  Actually, we stayed there in the hopes that this one would not catch on fire, thus proving that our experience in Louisiana was a fluke.  It didn’t, so we’re in the clear, jinx-wise.

Our final stop before parking the Airstream was the truck wash in Tucson.  I was amazed at how much salt and gunk was still on the trailer after our rinse-down in Corpus Christi.  Add to that the accumulated bug guts of an 1,100 mile high-speed tow, and you can imagine how the Airstream looked.  It deserved a good bath before we put it away, and now it looks shiny and ready for another adventure.