Thursday, May 28, 2009

Windshield Wiper Assembly

As stated in the last entry, the wiper assembly for the Rally Fighter's was one of the components worked on with ATG out in California.

At first glance windshield wipers seem to be extremely simple with few moving parts, but this is a misconception. Beyond the technical workings of the wiper assemblies their are strict FMVSS (Federal Motor Vehicle Safety Standards) as set by the U.S. Department of Transportation.

The windshield wipers on a car use two mechanical parts to move.

First, there is a combination of an electric motor and a worm gear reduction
(shown below) which provides power to the wipers. This uses a standard electric motor which spins a worm gear. A worm gear reduction is used since it both reduces the speed of the motor and increases the torque by the same factor of about 45 . So when the wiper motor is spinning, the resulting speed after the worm gear is 45 times slower and the resulting torque 45 times greater. This high torque is necessary to move the wipers quickly and powerfully.

Second, their is a linkage (shown below) that converts the rotational output of the motor into the back-and-forth motion of the wipers. The linkage uses a cam attached to the worm gear reduction
(A cam is a mechanism that translates movement from circular to reciprocating or oscillating. An example is the camshaft of an automobile, which takes the rotational motion of the engine and translates it into the reciprocating motion necessary to operate the intake and exhaust valves of the cylinders.). As the motor and gearing spins, the cam operates a long arm by moving it back and fourth. This long arm is connected to two smaller arms which attach to the right and left wiper blades. This linkage pushes and pulls with the converted force to move the wiper blades along their path.

Check out this video of the Rally Fighter wiper assembly:

Tell us what you think!

Tuesday, May 26, 2009

Trip to ATG in California

Trip to ATG in California

Last week Local Motors lead engineer Dave Riha was out in California with ATG (Automotive Technology Group) to work on some components for the Rally Fighter.

The main goal of this trip was to make the discussion between body tooling design and engineering more cohesive. We wanted to make sure our vision for the Rally Fighter was not lost. Dave, with support from the Local Motors team worked on the following components which will be explained in subsequent entry's:

  • windshield wipers
  • grill and bumper/nose
  • quarter panels
  • cowl
  • door liner
  • door jam
  • trunk liner
  • window track extrusions
  • weather strips

Through the work Dave did while in California we gained valuable insight to how ATG's body design process works. Just learning their style of working and their typical schedules helped us greatly with our work with them. Being there in person improved the effectiveness of the work since up until this trip everything had been done by email or phone.

Our own internal communication effectiveness also improved through this trip. We had to prepare multiple diagrams everyday to support Dave and his effort. Any mistake would have cost us time and money since we are on a tight schedule and Dave was only in California for a little over a week. Without good communication the work accomplished would have been impossible.

Dave said that after leaving he was confident that ATG was left with enough foresight to work in the right direction - towards our vision. This confidence in a contractor is crucial especially considering the Rally Fighter's fast time to market.

Check out this cool video of the wiper path:

Thanks ATG!

Tell us what you think

Tuesday, May 19, 2009

Is the Rally Fighter Green?...Safe?

Is the Rally Fighters diesel engine green?

As shown on the Buy Page, the Rally Fighter uses a BMW 335D engine. This engine produces a whooping 265 Horsepower @ 4200rpm, and 425 lbft @1750 RPM.

But don't let the performance fool you, this is a new 50 state legal clean diesel engine with urea injection. This engine already exists in two cars, the BMW 335d and the BMW X5 XDrive35d. The two vehicles have respective 23mpg city, 35 mpg highway, and 19mpg city, 25mpg highway.

But considering the Rally Fighter will be about 700 lbs less than the 335d sedan we expect a similar if not slightly better fuel economy.

But mpg is not the whole story.

The new BMW clean diesel engine has "20% less CO2 emissions" than a gasoline alternative. Beyond the reduction of co2 the new engines also utilize modern exhaust particulate filters, and urea injection in a system called BluePerformance:

"BluePerformance, it incorporates an oxidation catalyst placed just downstream of the exhaust manifold, a diesel particulate filter (DPF) housed in the same unit, and an SCR catalyst incorporating urea injection. In addition to filtering out even the smallest particles from the exhaust gas, this combination ensures effective reduction of nitric oxides (NOx) by way of a chemical reaction within the exhaust system. This reaction is initiated by the injection of a small dose of urea, or "AdBlue." AdBlue is already widely used in Europe. The ammonia generated within the SCR catalyst converts nitric oxides into nitrogen (N2) and water vapor (H2O)." - BMW USA

Is the Rally Fighter safe?

The short answer is yes. We have engineered the Rally Fighter to meet or exceed all FMVSS (Federal Motor Vehicle Safety Standards) as set by the U.S. Department of Transportation.

Click here for the standards.

Tell us what you think!

Monday, May 18, 2009

More Help from the Community !

This time the help came from the design side of the community, compared to the recent head's up I received from one of our fellow engineers in the community.

We recently received an email with a link to an post highlighting the process of removing the battery from a Better Place vehicle. According to the post, the swap only takes one minute and thirteen seconds, and you don't have to get out of the car to do it. This is pretty amazing considering the initial estimates we saw some time ago on how long it would take to accomplish such a feat. However, as you will see in the video below, the equipment is (as expected) pretty complex and takes up quite a bit of space since the battery is just about as wide and long as the entire vehicle. The positives are that they feature solar panels to power the aparatus, and the systems seem to be pretty universal. It will be interesting to see how well the systems can be integrated.

Thanks to one of our dedicated community members, Braunarsch for the head's up!

Wednesday, May 6, 2009

More Progress on the Chassis Jig Tables

Colby Whipple (LM's master welder) built and painted four beautiful surface plates for the construction of the Rally Fighter’s chassis jigs. See the April 29th entry for more information about the construction of these multi purpose tables.

Once all the tables were constructed Colby put two coats of paint on the bases of the tables.

After a couple days waiting for paint to dry it was time to flip the tables. This was no easy task considering each of the four tables weigh about 1,500 pounds. We had to use a fork lift and vise grips to flip the tables onto their sides, and then push the tables over. This is illustrated in the following video.

After the tables were flipped we brought them to their somewhat permanent spot in the shop for assembling the Rally Fighter's chassis jigs and eventually other jigs for future vehicles. We placed and silicon glued aluminum panels to the floor surrounding the tables to protect the floor from welding sparks and other debris.

Tell us what you think.

Tuesday, May 5, 2009

Adding to the Glossary
We have been updating the glossary with LM engineering definitions. The updates are new definitions and images brought to us by The purpose of these updates from, and links to, is to strengthen the
LM engineering community.

This wont go live for 24 hours but we have added the definitions of:

  • Twin I-Beam Suspension
  • Trailing-arm Suspension
  • Double Wishbone Suspension
  • Springs
  • Shock Absorbers
  • Drum Brakes
  • Disk Brakes
  • Engine Layout
  • Variable Valve Timing
  • 2 and 4 Stroke Diesel Engines
  • Fuel Injection
  • Spark Plugs
  • 2 Stroke Petrol Engines
  • Interference vs. Non-Interference Engines
More to come, have fun learning!!

Tell us what you think.

Huge thanks to Chris Longhurst of

Friday, May 1, 2009

Engineering Support from the Community

I received an email from one of our community members, Saffp7 the other day informing me of yet another new engine that improves upon the current model of combustion engines.

Here's what the Windor Star had to say about the Windsor, Ontario company, Vengeance Power Inc.:

"[The engine] runs on nine main parts instead of the 30 most combustion engines have and is considerably lighter. It doesn't need a transmission or catalytic converter. It has three times the power for its size. It's twice as fuel efficient as a gasoline engine and 25 per cent more fuel efficient than a diesel engine. It can use any kind of fuel including diesel, biofuels, natural gas and eventually hydrogen fuels."

Definitely sounds like it has some great potential as a disruptive engine technology, and since disruption is what we're all about, I'll be adding it to my list of engines to keep an eye on.