May 27, 2008

We have made a lot of progress since the last posting.

The chassis is on the ground for the first time.

We finally removed the engine and rear suspension from what was left of the MR2

Matt with the Positioning Jig he just built. He put steel up to the MR2 chassis critical engine and suspension mounting points. Then he welded the steel and drilled holes to match those on the MR2 chassis. We will use this jig to assure that our rear engine and suspension support structures and accurate and will fit the engine and suspension.

Rear structure being built over Positioning Jig

May 29 Update

Since we drastically changed the Toyoto MR2 Steering hubs we had to totally re-calculate all the steering geometries. We had to set up the "scrub radius", camber, caster, and akerman. We calculated maximum front wheel turning angles using the new steering rack we bought. This rack has a lot less travel than the stock Toyota MR2 rack. This means we have less steering wheel turns lock to lock. Now we will also have more steering effort. We have to shorten the steering arms to get the turning radius with less rack travel.

After calculating and mapping the proper pivot point for the tie rod ends, matt cut the Toyota Steering Arms and ground and welded them back to gether.

Jim and Matt studied Akerman Steering and built a two dimensional mock-up to test the steering geometry. This will assure that in a tight turn, the inside front wheel will turn the proper amount more than the outside wheel (the is travelling a smaller diameter radius in a turn). We also made a 2D graphic of the front fender to study tire clearance in a full-lock turning situation.

May 28 Update

Stas and Tay help with clay modeling of full size model. The goal is to have it ready to take a fiberglass mold off of it before the summer school session starts.

May 7 Update

The new steering rack can barely be seen just behind the horizontal yellow tubing. Matt Briggs was working on this when he received the tragic news that his sister had died that night. We immedietely booked a flight to Rochester New York so he could be with his family.

Paul stopped by to help. It was his first experience working on a full size model and he noted how the scale of the tools to the size of the model is very different than working on a 1/5 scale model. Paul moved quickly and filled in new clay between the rear fenders to make more room for the Toyota engine that will eventually be under this area.

Here Napolean is raking the fresh clay he has just applied to the right front fender.

Continuing the clay surfacing

Napoleon enjoys a well earned "fantasy" after completing the "packing" of the hot clay over the entire center body surface. Only the two front fenders remain for "packing". He used gloves because the clay is 160 degrees and can blister your hands if left there for more than a few seconds. After the clay cools, it will be very hard for final surfacing and eventual mold making.

Napoleon and Stas continue to surface the "model buck" (made from wood and foam and on casters). The first application of clay is called "packing" the clay. It is hard, physical work smashing the clay onto and into the foam so that it will be secure for final shaping.

Applying the Surfacing Clay

In this image, Jim is shaping the clay using a piece of spring steel that has small teeth cut into one edge. Previous to this, he roughed out the surface using a tool called a "rake" that looks a bit like a garden rake. It too is a piece of steel with teeth in it, but it is attached to a handle and is used for the initial quick cutting and shaping of the clay. It is easier to do the initial shaping of the clay while it is still a little warm. After the clay has cooled off completely, it becomes quite hard and is more difficult to shape.

In this photo, Matt is applying the hot clay to the surface of the foam "clay buck".

In this photo, Matt Briggs is putting billets of clay into the clay oven to heat it so that it will be soft enough to apply over the blue foam. The wood and foam structure upon which the clay is applied is called the "clay buck".

The Clay we are using was donated by Mitsubishi Motors thanks to arrangements made by Raymond Chan (a student at the Academy of Art University who interned at Mitsubishi last summer) and supported by the Academy based on the fact that several students will gain valuable experience helping to build the full size clay model.

This clay is the same clay used by the car companies for making body models. It is first heated in an oven to 160 degrees to make it soft for application to the foam. As it starts to cool, it will become more firm and hard and then can be formed using specialized clay modeling tools. When fully cooled, the clay surface becomes quite hard.

Eventually, we will be making fiberglass molds from the clay surfaces. Then we will be making fiberglass parts in these molds.

Priming the foam before applying the clay

We have painted the surface of the blue foam with a Shellac so that the clay will stick to the foam.