Curbside Classic: Ultra Van – Cross An Airplane With A Corvair For The Most Radical RV Ever

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– Posted on August 9, 2022

(first posted here on 5/30/2012)

In 1959, David Peterson, a professional aircraft designer, had a dilemma: he owned a travel trailer and a boat, but couldn’t tow them both at the same time. He dreamed of putting an engine under the floor of the trailer, and towing his boat with it. When the Corvair appeared that year, he decided to act on it. He rented a large garage, tossed out the trailer, started from scratch, and four months later out rolled the first Ultra Van, a full sized motor home, but weighing a mere 3,000 pounds. It was way ahead of its time then, and it still is today. Which probably explains why it was a commercial flop, as well as being my all-time favorite RV ever.

To help put the UV into perspective, here are a few basic stats: it’s a “full size” RV, 22 feet long, 8 feet wide with full 6’2″ stand-up headroom, yet it’s only 8′ tall overall. It has all the usual amenities of a Class A RV, including a large bedroom in the back, full galley, bathroom, etc. The production versions weigh about 3,400 lbs (dry), about the same as a new Camry. And it can get up to twenty mpg on the road.

It’s one of the all-time most brilliant marvels of space and weight efficiency; if Colin Chapman, Buckminster Fuller, Ferdinand Porsche or Gordon Murray had been asked to design an RV, this is what they would have come up with. David Peterson deserves to join their hallowed ranks.

If you’re getting the drift that I rather like the UV, you’re right. I’ve obsessed on them since my first sighting as a kid. I knew instantly that it was something different. Then I read an article about it in a Popular Mechanix or such: Wow! A Corvair-powered RV built like an airplane. How cool is that? Ultra Cool!

And as an RVer, the UV is truly my dream rig. And one I have spent way too much time imagining how to update and improve, never mind just own. Before we get to that, here’s the history and the details of my heart throb:

Peterson didn’t just transplant a Corvair engine under his travel trailer. He started from scratch, and designed the only RV (to my knowledge) that was built just like an airplane, where light weight is paramount. The UV is a true monococque (self supporting) structure of aluminum ribs with an aluminum skin riveted to it. The aerodynamic front and rear caps are fiberglass, and those bumpers are made of foam.There are four aluminum tanks for gasoline, water, gray water and sewage carefully integrated under the floor, and the bottom of the coach is fully sheathed in aluminum skin as well.

It’s important to understand that Peterson wasn’t just trying to build the world’s lightest RV. His goal was that the UV could also be used as a second car too, unlike the large and unwieldy RVs that were (and still are) being built on truck chassis. The UV was not that much longer than the big land yachts at the time, and its steering allowed a 50 degree inside wheel angle so that it was also very maneuverable.  And of course, its fuel efficiency played into that too. Even if it wasn’t exactly going to be used daily, in any case, there certainly was no need to have a dingy car towed along behind.

In my obvious enthusiasm, I’ve jumped ahead of the story a bit, because originally Peterson had no plans to build his invention for others. But he got pestered about it enough that he found some technical school apprentices, and built fifteen of them. They were priced at $7,000 ($50k adjusted). And those early ones had all of 80 hp, which feeding through the two-speed Powerglide meant a leisurely ride, especially with a boat in tow.

In 1964, a Wichita Kansas company bought rights to build the UV, in an attempt to properly commercialize it. But only some 330 Corvair powered UVs were ever built before production ended in 1969, for several reasons. One of them was that the Corvair was known to be ending its production, meaning no new engines. But the biggest reason by far was Winnebago.

In 1966, Winnebago revolutionized the RV industry by offering Americans the equivalent of the Big Mac Value Meal, an family-sized RV for half the price of the going rate. They did it the Henry Ford way: it was the first mass-produced production-line RV. And it was the polar opposite of the UV in every way: a cheaply framed box sitting on a cheap truck chassis; heavy, gas-sucking, ill-handling; and Americans snapped them up as fast as Winnebago could make them. Cheap, big and inefficient: the American mantra for success whether it’s with cars, houses, or a cross between the two.

The UV’s brilliance was also its downfall. Its airplane construction was intrinsically more expensive.  If gasoline had always been at European levels here, there would likely be an UV dealer down the road today.

After 1964, Ultra Vans came with the bigger 164 CID Corvair engine (directly underneath these rear beds) in both 110 and 140 hp tune. Since a manual shift linkage was out of question, they still pumped through the Powerglide. For those more leisurely times, the Corvair engine did the trick, cruising happily up to 65 mph (on flat terrain). But by the late sixties Americans were getting power-hungry, even with their RVs.

So after the Corvair engine went bye-bye, Ultra engineers tested several alternatives. The Olds Toronado FWD power train was promising, and versions with it in the front and back (not both at the same time) were tried. These experiments led to to two new developments: the fwd Toro-powered fwd Tiara, which we’ll take a look at in  separate post. But the Ultra experimental department kept at it, and finally hit on a solution to replace the weak chested Corvair: “Corvette” power! A 200hp 307 inch³ Chevy V8, actually, although some higher-performance 327s were known to be specified by those looking for more. The benefits of Chevy small-block power: take your pick of horsepower.

As best as I can make out from the iffy descriptions, the small block Chevy V8 sits in the back under a rear bed, and then sends its power to the rear through a Powerglide, then a marine V-drive sends it back forward to a Corvette independent rear suspension with disc brakes. Ultra sophisticated or ultra crude?

These so-called “Corvette” Ultra Vans have sparkling performance with their very un-RV like power-to-weight ratio. Mileage dropped to a still respectable 12 -15 mpg. Only 47 of these were made, of which some are still prowling the roads of America looking for stoplight drags with Chrysler 440 powered Winnebagos in order to settle an old score.

It was all in vain; the UV was getting ever-more ultra-expensive, and Ultra shut its doors in 1970. The 375 hp fwd Toronado-powered Tiara (above) had even more sparkling performance, with an unparalleled 16:1 lbs/hp ratio; Petersen said that if the Toronado had been available in 1960, there never would have been a Corvair UV.

His ideas were picked up by others, including the second-most radical RV ever built, the GMC Motor Coach (above). But Ultra was down and out.

Ultra Vans have an enthusiastic and loyal following, and some 200 of the 370 ever built are still on the road, or hoping to be soon. Obviously, there are challenges and limitations to Ultra Vanning: one has to travel lightly, since its total weight capacity is limited, especially with those little 14″ tires (early ones had 13 inchers!). This UV has obviously and wisely had its rims widened. There’s no air conditioner. The brakes are unassisted drums. The tanks and complex sewage system can become problematic. At least there’s no power steering to get leaky. You get the drift: this is for minimalistic RVers, which suits me fine.

As the owner of UV #366 shows to an extreme. A former pilot, he’s stripped his UV to the bare essentials in the quest to make what has to be the world’s lightest full-size RV.

No dashboard, just what looks like a bicycle speedometer. Who needs any other gauges anyway? (I’ve lost two now on my Chinook, and I’m managing OK). And the steering wheel is down to one spoke. This guy is very serious about weight reduction.

OK, if I was single, I might be able to relate to this. But I don’t think I’d get very far with Stephanie with this degree of minimalism; like not even past the front door. But I respect what he’s after, and I’d bet his UV weighs in at under 3000 lbs.

When I was young, I shared Peterson’s dream: whenever I saw an Airstream trailer, I imagined turning it into a self propelled sleek and low RV. I became aware of the UV in the sixties, having seen their unique shape and read about them. Simply put: this is the RV I am most obsessed with, and have been for decades. The idea of a sub-4000 lbs but roomy RV, one that has great traction and doesn’t need power steering, and has a superbly low center of gravity, and a Corvair engine: in an alternate life, where I don’t have a dozen old houses to attend to, I’d live in a little new house with a big garage, and create my own customized Ultra Van. I’ve played out many re-powering scenarios: a Porsche air-cooled six with a Tiptronic with 911 suspension and brake upgrades was a long favorite (there is at least one 911-powered UV out there).

Now I lean more to maximum mileage: a Subaru turbo-diesel boxer (sold in Europe) is the current candidate. But how to change the rotation, after flipping the drivetrain 180 degrees? Or maybe a 140hp Jetta/Passat TDI with six-speed automatic would fit between the rear wheels without intruding into the living space too much. That’s the one I’ve been MMing the most about.

I’m convinced a UV would hit 25 mpg easily with a modern turbo-diesel. The big question is, could it hit 30 mpg? Possibly, with a few aerodynamic tweaks and such. That’s the kind of mind-games that sometimes keeps me awake at night. Its low clearance and lack of off-road capability, as well as the huge amount of time and energy it would take has so far kept me from Ultra-insanity.

UV #366 image source: pilkguns.com/ultra

Nothing remotely as advanced of an RV body structure has been attempted since UV shut down in 1970. I’m rather intrigued with the idea of whether a modernized update on the UV would be able to find a market today. Perhaps one using some little turbo-diesel, or the Prius’ hybrid drivetrain, or even an all-EV version, since every campground has electric hookups. No more fuel cost whatsoever! With perhaps a 100 mile range, one would be forced into leisurely excursions, but isn’t that the point? Solar panels on the roof and on a pull-out awning for charging batteries in undeveloped sites. My imagination runs rampant, like David Peterson’s. The trick is knowing whether to act on them, or not.