Aaron Cantrell
Home

As part of my thesis work at Hampshire College, I undertook a project that offers a wide number of facets to investigate. This project is an active investigation into small scale aerial vehicles, their applications, and prototyping methods that lend to the iterative design processes needed to refine them. The first phase of the project is focusing on using CNC technology paired with parametrically intent driven models that allow different chassis and designs to be tested in a rapid fashion. It is my hope to minimize the turn around time to be able to move from one test vehicle to the next iteration being fully redesigned, cut, electronics transplanted and flight ready in less than 72 hours and under $20 materials per model. The core of the process includes surface based modeling using SolidWorks and building the models in a way that a driving root sketch defines all the core dimensions so that modifications to the design can be completed in less than 30 seconds if a change is needed. The couple of funny looking screenshots at the bottom are examples of the flexibility of the model, they took less than a minute to tweak. Although they would likely never fly, they demonstrate the quality of fore thought and design intent that went into creating such a flexible surface based model.

All modeling is completed in SolidWorks, allowing for easy center of mass calculation relative to the approximate center of lift of the vehicle, a core consideration when building airplanes. I have started the process of experimenting with FlowSimulation to establish the true center of lift of the vehicle. After the physical geometry and layout is completed in SolidWorks, I do all the CAM programing using 3-axis milling operations in MasterCAM. Since the planes are made out of foam and the router I'm using can spin at 14,000 RPM, I can get away with cutting at 90 IPM and full 2" flute length cuts. After I have milled the foam core, I cut off the holding tabs and quickly sand the chassis. From there I apply a epoxy resin to the exterior which creates a hard shell and significantly increases the structural integrity of the wings. The control surfaces are hand cut after the epoxy as the foam isn't dimensionally stable enough if epoxy is applied post cutting. Individual pieces are all epoxied together and the electronics and servos are installed, completing the fabrication of a geometrically precise model.

The second phase of the project is going to be experimenting with a set of specific applications. The initial ideas was to explore the applications of the technology in a open-ended way, but due to the limited timeline of the project, we are in the process of deciding which application we will focus on. Over the course of the time I've spent working with rapid prototyping technology I have started to question if it would be possible to re-conceptualize the way in which we create certain products and to work towards a local products movement that would empower people to use communal shops to create custom products.

LGATLL