By on May 4, 2010

Three-wheeled cars offer unique advantages in aerodynamic design and build costs, but they also work from a fundamental disadvantage in terms of handling. Put simply, three wheels can not possibly generate the same levels of mechanical grip as a four-wheel design. EV startup Aptera, which recently unveiled its “design intent” 2e EV, found out just how hard it can be to make a three-wheeled design operate to mainstream standards during shakedowns for the Automotive X-Prize in which it is competing.

Aptera’s difficulties centered on the lane-change test, in which the vehicle must accelerate to 45 mph and then maneuver through a simulated lane change without contacting the cones that delineate the course. Consumer Reports describes Aptera’s issues:

Watched by a large group, including many note-taking and video-taping team members, the three-wheeled Aptera car struggled to find a clean run. More than two dozen attempts were made, with the car routinely sliding enough to topple several cones. In watching, it seemed natural to question how difficult this test is to pass. However, all current production vehicles, from small cars to large trucks, can successfully negotiate this test. We expect the Auto X Prize finalists to do the same.

The video above shows just how wild the three-wheeled wobbling was. Aptera, meanwhile is downplaying its struggles, describing the ordeal in its April newsletter thusly:

The first dynamic event was the 0 – 60 mph acceleration, followed closely by the 60 – 0 mph deceleration event, which provided little challenge for the 2e. After a few short passes, the team was off to the next event: the double-lane-change maneuver, which was not as much of a cakewalk. Without the benefit of prior ride development, the 2e repeatedly passed through the course, but 1 – 1.5 mph below the required speed. The challenge was particularly frustrating because the double-lane-change is a standard part of Aptera’s development plan, but the team simply hadn’t had the opportunity to tune the vehicle yet.

Passing the gate was the only option, so the Aptera team loaded up on caffeine and worked into the night to adjust the suspension for better handling through the course. Then, when the call came for Aptera to retake the test, the team showed up at the track with tuning gear in hand and iterated the vehicle set-up right there on the track until it floated through the trap at the mandated speed.

In other words, the “production intent” 2e has had no suspension tuning done to it. And, as disgruntled fans at the Aptera Forum note, the “production intent” design’s inclusion of weight-adding luxuries like cupholders and roll-up windows likely added to the 2e’s woes. Chalk up another bit of evidence in support of critics like former Tesla PR man Darryl Siry, who argues that:

If Aptera had launched a limited volume run of vehicles in 2008 to rabid early adopters who would never complain about roll down windows they would be well on their way to a better product, would have more market traction, and would have loads more credibility.

Good luck getting that genie back in the bottle.

[UPDATE: Aptera passed the handling text the next day, according to a rep from the marketing/communications firm PCGCampbell]

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25 Comments on “Aptera Runs Into Handling Trouble In X-Prize Shakedown...”

  • avatar

    “These will be… literally, ground-breaking vehicles.”

    Really? I’m guessing that the department of public works is going to have something to say about that…

  • avatar

    For me, credibility of this test dropped to zero as soon as I discovered that CR was involved. Never ever forget that this is the organization which faked its rollover test of the Suzuki Samurai when it declined to fail as they intended.

  • avatar

    How does that orange thing stay upright with even the slightest crosswind ?

  • avatar

    This is a textbook example of people with their heads in the clouds developing a product that people don’t really want.

    People don’t want an unstable 3-wheeled car with outriggers, no matter how perfectly aerodynamic or efficient it is. It’s amazing that this simple truth eluded Aptera’s designers from the beginning.

  • avatar
    Ken Magalnik

    Seems like someone is trying to make a mountain out of a molehill. I can think of a few three wheeled vehicles that would not have a problem passing this test, and I would be surprised if aptera’s problems persist past the suspension tuning stage. On the flip side, I am fairly certain that one can ruin the suspension of the most stable of vehicles to the point that this sort of maneuver is impossible.

  • avatar

    I’d like to see the “climbing a snowy hill in New England” test. That single rear tire isn’t going to cut it even if you manage to find a Blizzak to fit it.

  • avatar

    Trikes are almost always inherently unstable in turns. The worst of both worlds. Less contact patch and mechanical grip than a four-wheeled vehicle and you can’t lean it over to improve cornering like a bike. Old Morgan three-wheelers could corner because they had a very low center of gravity, but as traditional as Morgan has been, even they went to four wheels. One criticism of Bombardier’s CanAm Spyder three-wheeler is skittish handling.

  • avatar

    I am SICK AND TIRED of the “Model T gets the same gas mileage” statements. NO Model T ever got 25MPG at 70MPH because they couldn’t go that fast. It is a bullsh*t meaningless statement that they should be called on. High gas mileage is due to three things, efficient engine/drivetrain, low wind resistance/rolling resistance, and light weight. No secrets.

    • 0 avatar

      Yeah, I was thinking the same thing. I’ve heard the Model T can get “up to” 20mpg, probably at 30mph in top gear. Weren’t they like 4:1 compression? Drive a modern 4 cylinder car like that, and you’ll get 40 mpg or better. But no one is willing to go 30mph on the highway these days. (thankfully!)

    • 0 avatar

      Believe it or not, the 45 mph minimum speed limit on the Interstate Expressway System was designed to keep Model-T era cars away.

    • 0 avatar

      “No secrets.”

      You’re right, although for the XPrize, secrets do play into the calculation. Electric cars are given a huge advantage over diesels or gasoline-fueled cars. The competition uses a pump (or plug)-to-wheels metric, so the inefficient part of the energy usage cycle (burning coal for electricity or burning gasoline in the car’s engine) is accounted for in one case, but not the other. Thus, an old RAV4 EV is rated at over 100 MPGe, per the XPrize rules: throw an electric motor and some old tech batteries in a boxy little SUV, and you’ve won the competition. Nissan used similar logic(?) in calling the Leaf a 367 MPGe vehicle.

      The old GM EV1 is much more efficient than the RAV4 EV was, so it could win this competition, with loads of room to spare. And unlike the Aptera, it could actually go around corners.

  • avatar

    >>Put simply, three wheels can not possibly generate the same levels of mechanical grip as a four-wheel design.<<

    In fact, three wheelers can handle very well, with, for example, the T-Rex generating cornering forces over 1G. The problem is simply bad engineering, just as bad engineering led to flaming Pintos, flipping Explorers, and spinning Corvairs. Aptera's reputation will not be helped by the door flying open during the test, either, but again, that is not a fault of three wheelers, it is just another sign of bad engineering. Other three-wheelers made it through the handling test just fine.

    Ronnie's comment is not quite on the mark: the ratio of contact patch to weight at each wheel can be as high in a three wheeler as in a four wheeler. A three-wheeler can be engineered for anything from opressive understeer to snap oversteer, and anything in between.

  • avatar

    Is the driver’s door really supposed to act as an aerodynamic-stabiliser/dive-brake?

    • 0 avatar

      The Aptera doors are automatically deployed in maneuvering — somewhat like the arms of a figure skater. The rear hatch can be deployed to cause the front wheels to lift over obstacles such as pedestrians.

  • avatar

    Much of what I’ve heard from Aptera in the past 12-18 months leads me to believe (and increasingly so) that this group is more than somewhat lacking in the clue department.

    I agree with KenFry that 3-wheelers can be designed/tuned to handle however, and that failure of critical tests is a sign of bad engineering. I know for a fact that companies making non-highway low-speed (<25 mph) vehicles have their testing ducks in a row far above and beyond what Aptera indicates.

    I did hear some spec about the Aptera's weight distribution being 67/33 so that each tire had an equal loading, which to me sounded like a recipe for borderline oversteer. They need to push more toward 75/25 to make it easier to transfer weight to the front tire and induce stable understeer or put one heck of a high roll stiffness in the front end.

  • avatar

    They should have tried it with a proven design like this Morgan Three-wheeler:
    (alas, w/o cup holders)

  • avatar

    Robert.Walter, I have to agree, that self actuatig door was a little more disconcerting than it’s lack of adhesion. Maybe it is the secret James Bond Aptera. Where’s M?

    • 0 avatar

      Maybe it’s like the door jettison feature on aerobatic airplanes. When the Aptera senses a severe driver-intent/car-response mismatch, the door pops open to allow the driver to jump out.

    • 0 avatar

      Or maybe its just the body of the vehicle flexing enough to pop the door latch out of place.
      Whatever the reason, its pretty embarrasing.

    • 0 avatar

      Things like a door popping open are pretty embarrassing. But they do not mean that much. It’s a superficial engineering fault that can be corrected. Not a conceptual fault that invalidates the design.

      I hope that those judging the X-Prize cars will focus on concepts rather than flash. That can be hard to do.

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