Moon Buggy
Ryan will graduate a couple of weeks from now with a degree in mechanical engineering. But before he graduates he must complete his senior design project. Ryan is president of the Moon Buggy team. The project.
Think four wheel human powered ATV.
Is it okay to mention this project on our GT 40 build blog? Since a lot of what he learned building the GT influenced the buggy, I see a correlation. So just for fun some details will follow.
Ryan started designing the project about a year ago using the Pro Engineer software. Once the chassis and suspension were designed one could view the images in three dimensions, rotating them on screen. Moving assemblies, like the suspension, could be moved on screen through their ranges of travel, revealing any conflicts. I found it amazing that once construction began the components looked exactly like they did on the computer screen and fit remarkably well without conflicts.
The chassis and all related components were built from Chromalloy steel. The size and thickness was dictated by data from a structural analysis – using the computer modeling. (ANSYS Workbench). A jig board was made with moveable sections so all major components could be precisely build per the computer design. All joints were tig welded. Ryan spent countless hours welding over the last six months (and a half dozen tanks of argon to prove it).
The suspension was designed to have minimal bump steer, adjustable heim joints for camber and caster, appropriate roll center and appropriate Ackerman. Maximum suspension travel was incorporated, since this is an 'off road' vehicle. It tracks remarkably well.
The shocks are mounted inboard and have rocker arms with connecting rods joining them to the lower A arms. 7.5 inches of wheel travel translates to 2.5 inches of shock travel.
Splined half shafts transmit power from the differential to the wheels (like the GT). The uprights were fabricated on a jig to assure uniformity and box construction used for strength and minimal weight.
Close attention was paid to construction techniques referencing Carroll Smith's books. Rod ends were not used in single shear. All fasteners were either wire tied, nyloc nut, or Lock Tite to keep them secure.
Here is the tricky part. In an effort to simulate the original moon buggy (currently parked 250,000 miles away), this project must fold into a four foot square cube (just like the original). The chassis has a pivot in the center and both the seat backs and pedal supports fold.
The rules require a 'simulated control panel.' Ryan elected to use an I Phone with a speed application for that purpose, inspired by the control panel in Fran's Cadillac roadster.
On Friday and Saturday, April 26 and 27, Ryan and the other team members will trailer the moon buggy to Huntsville, AL for the international competition. There will be two competitions: best engineered buggy and fastest around the course. About 100 teams will be present from all over the world (the German team usually has a strong entry).
So what does this have to do with the GT 40? It explains why we have not done anything on the GT for a several months.
