Engineering Projects/StrandBeest/Howard Community College/fall2012/p1-550-owa

Problem Statement

Work as a team to document the design and build a functioning Strandbeest using cardboard and other easily obtainable materials .

Team Members

Osborne
Wilson
Amoh

Summary

Our goal as a team is to work together to design and build a working strandbeest made out of inexpensive, easily obtainable materials. Individually, we gather information and work on ideas, document them, and bring those ideas together to decide on which ones we will continue working on and which ones will be discarded. ultimately the collection of ideas is what the strandbeest will consist of.

Story

Before we began building the strandbeest, our group made multiple online searches to find out which model is the best to build a strandbeest. After looking at some models online, we decided that each member would build a prototype. We would then bring in our prototypes and compare to see which model was the easiest to make, and which would be the most likely to create a plausible strandbeest. Once the weekend was over, we compared our prototypes, and decided that we would create a large strandbeest that would be wind powered. We assigned different tasks to each member. One member would create a wind powered engine, another member would create the remaining strandbeest legs, and the final member would create a chassis to support the strandbeest. Unfortunately, a problem occurred. Our client did not like our design, and wanted a strandbeest that was smaller and easier to make. Our group had to start over, and create a miniature strandbeest that could be made out of household materials. After some discussion, we decided to reassign to the same tasks but cater them to fit the needs of a miniature strandbeest. The pictures you see below are of the initial wooden leg we designed which was not approved by our client due to the fact that it was too costly and much too large. The wooden leg was very functional but we had to find a new approach. We designed a crank shaft out of washers, nuts, and a long fine thread piece of bolt. We then came to realize that the way the crankshaft was set up would not work because it would come apart at the washers due to too much stress. We then found a sheet of very thin aluminum that we cut to replace the part of the crankshaft that might come apart. We have also found the "magic numbers" for the dimensions on Theo Jansens website which can be found here. He calls these the holy numbers and we are now in the process of converting these numbers to the size we need to function well with our existing crankshaft.

Strandbeest Tabs

Strandbeest tabs

Here are a couple of videos we were able to find showing different types of Strandbeest designs and different materials were being used. We are in the process of deciding what the best material would be to use and these seem to be the top few: Drinking Straw Strandbeest Paper Strandbeest

Also we have worked on designing a leg to work with for the Strandbeest and this is something we have so far:

Material List

• Used Coors lite box cost-free
• brand new paper clip cost < 1 cent
• 18 feet of wooden screen molding cost-$0.64 per foot
• 1-1 foot threaded bolt cost-$0.98
• 2-8 pack of washers cost $1.18 each
• 2-12 pack of #8-32 nuts cost $1.18
• 6 small bolts cost $0.15 each
• 24 small nuts cost $0.08 each
• 8 X 10 inch sheet of Aluminum $2.09

additional material is needed for the strandbeest body and if modifications are made to the drive shaft.

Software List

None

Time

22 hours 30 minutes. 15 hours 45 minutes.

All together a combined 38 hours.

Tutorials

No tutorials

Next Steps

It is our recommendation that the next team create stronger tabs to make the crankshaft out of. The current crankshaft tabs are made out of aluminum, which are soft and give the entire crankshaft too much play. Furthermore the body and legs need to be designed and constructed. It is important to use the "holy numbers" when designing. In addition, a method for creating a crankshaft by bending one piece of a very strong, thin metal rod, would be an easier less time consuming, less expensive method for recreating multiple crankshafts. Another concern was the construction of the legs. Advice to the next team is to try and make it out of straws but make several of the legs so that it will be able to support whatever weight is needed to power it and also DO NOT use bending straws if you are going to attempt making the legs out of straw. They are too short and will not work if you do not cut the bending part out.