Spring Week 8-9

Hello everyone! Our team had COVID-related issues for the last two weeks and we finally had the chance to meet all together in person on Tuesday. Some other updates for the week:

1. Meeting with Dave Beach: Sree and Jierui had a meeting with Dave Beach to discuss easier sourcing methods for materials since a lot of items like pre-made cutter shafts were only available off of agriculture catalogs. While he didn't have other alternatives to this problem, he helped us think through our ideal axle design. We came up with a design which involved cylindrical hollow metal around the metal rod (that is turned by the gear). We would have to cut thicker sheet metal and for the caps of the cylinder and drill a hole for the metal rod to go through. We would likely have to press fit or cross pin the caps onto the cylinder. Unfortunately we cannot do this since only Jierui knows how to use the lathe and how to press fit and it would take much more time to finish. Instead, we are going to outline the design on CAD and all the materials and techniques needed to complete the design.

Dave Beach's drawings/notes

We also discussed our issue getting hammer blades and managing their weight with a scaled down prototype. He suggested we can try custom making L-shaped sheet metal since it's a rough approximation and use it for preliminary testing. We have already made our custom 'blades' and we are going to weld it onto the rod on Thursday so we can do  preliminary tests until the hammer blades arrive.  We measured the angle of the hammer blades at the bend and bent the metal to be this exact angle (85 degrees). We also used the relative size of the blades to the axle and maintained that ratio constant in order to make it a closer approximation. 

Alawab will also run some other calculations on how close the approximation is using parameters like its mass, momentum during a rotation and we will film it and compare it visually to how hammer blades rotate. 

Isabella has been running some tests on our previous prototypes. She is currently measuring the horizontal and vertical area it covers, to ensure a blade can cover the sufficient height and width of a cotton stalk. She is also measuring the rpm of the axle itself based on variable drill speeds, so if the drill we are using turns out to be too fast/too slow we can quantitatively approximate what speed is ideal. We also found some industrial specifications for flail mowers (very similar to what we've been building) here: http://ncsheriffs.org/Heavy%20Equipment%20Bid%2019-03-0504/Equipment%20to%20Add/Quality%20Equipment/Lot%2032/Copy%20of%20RF90ED%20%28Rear%20Flail%29030714.pdf. We will be comparing out prototype and which of these specifications it meets and doesn't meet. 

Next week, we'll likely present some experimental data we've gathered over the past weeks and start prepping for the presentation. See you next week!

​~Boomitra Team