This year we had the pleasure of supporting Northwestern Baja Racing Team, for the first time, with a material donation. PTG donated 662 Titanium Round Bar, 2.441″ Dia. George, Suspension Lead and Chief Engineer, was able to share with us about the vehicle and the benefits he’s experienced from being part of the team!
PTG: Can you give a brief history on your team? What’s your role? How has being a part of this benefited you?
George: Northwestern Baja has been around since the mid 80’s, but went to a skeleton crew of 2 people for a few years until about 2008 when 3 students halfway built a car, and then 2011-2012/2013 when a few legends finished the car and made it rules legal. That car is our first car, Spot, weighing in at over 550+ lbs. Knuckles was the 2013-2014/2015 car having been competed both years to correct issues with the initial radical design change that was at least 150+ lbs lighter. 2015-2016 (Elbows) was the year where our team really took off with good documentation and the use of more exact calculations for tribology and mechanical design. 2016-2017 (Bongo) was the first car I worked on as a freshman, machining shafts and welding the chassis together. It was very similar to Elbows but roomier with more driver clearance. 2017-2018 (Dino) was the year where we reoriented our goals as a team, our priorities and excelled in our machining. For 2017-2018 I was Manufacturing Lead where I helped tool out and setup machines for making the gear box housing and using the conversational lathe to its fullest ability. Knuckles and Elbows both struggled as cars with the gearbox input shaft constantly shearing due to an unaccounted for bending stress from the CVT pulley. Dino was the year where we fixed that issue and stopped failing Shaft 1. The cost of that was a shaft that grew to a nominal size of about 25mm in diameter from a previous 17mm. This year I was the Suspension Lead and de jure Chief Engineer (within the past 2 months due to the chief engineer graduating early). I’ve always been the one of the guys that knew everything that was up with the car and had a hand at some point with the manufacture of all the components. I have learned so much more than what your standard classroom experience has to offer and I have even learned what its like to be one of the guys making parts designed by someone else and learning all the issues that can arise from simple oversights.
PTG: What were your goals for this year’s competition?
George: The goal for this year was a response to last year’s over exuberance. Last year’s goal was to design for aggression. Light components everywhere, even to the point of riding the line of too light. This resulted in the loss of 7 camber links and the destruction of a CVT joint. Thus, this year we designed around reliability and optimization.
PTG: When was your first competition, and how did you do?
George: Our first competition with this new car was actually this past week. Final placing hasn’t been released but I expect we placed in the top 40s if not in the 30s.
PTG: We provided you with 662 round bar. How was this material used and why did you choose to go with titanium for these parts?
George: We used the 6-6-2 round bar for making shaft 1 and later, a bearing race. Shaft 1 was made from titanium to allow for both a lighter part and to allow for smaller bearings (in the form of roller bearings) to allow for less interference with the motor. While selecting roller bearings, a mistake was made and we discovered the roller bearing we purchased does not come with an inner race capable of taking an axial force (mainly needed for constraining the shaft) as well as requiring a 23mm abutment shoulder. A few concerns were that the shaft had already been roughed at this point and all the other hardware (snaprings, spacers and seals) had been selected around the 16mm diameter that the bearing ID was originally. I made an 1144 inner bearing race with the requisite abutment shoulder and added spaceoff distance to eliminate the need for one set of the spacers. This bearing race failed after 1 hour of service due to the low resistance to hertzian contact stresses. I remade the inner race with the same 6-6-2 Titanium which, until we have a chance to disassemble the gearbox to confirm, seems to have been very successful in implementation. The key symptom of the 1144 bearing race failure was the radial end play shaft 1 displayed after the hour of service. The Ti bearing race shows little to no change in end play from original assembly 4 hours of run time prior. I have high expectations and we plan to run this car for many more hours in the coming weeks for testing and data collection.
PTG: Has the team used titanium before? Do you machine the parts in house? And have you run into any challenges doing so?
George: Our team has not used Titanium before for any component. We do machine as many components in house as possible and that included the Titanium Shaft 1. Having been my first time machining Ti, It was a bit of a learning experience with both experimenting with different inserts another sponsor gave us and learning how to maintain the right surface footage on what was for all intents and purposes, an engine lathe with a conversational axis control. I quickly got a hang of it but struggled with keeping surface temperatures down even with flood coolant. The largest struggle actually came from attempting to drill out and tap the end of the shaft such that a bolt could be threaded in to maintain the CVT pulley on the shaft. I ended up making a bottle of taplight and water with a sprayer where I would drill in about .050 then retract and cool. After consulting shop professionals, tool geometry (and material) seemed to be my folly there more than anything else. The shaft was also difficult to tap but seemed to take well to the threads being cut despite some shrinkage issues due to heat. Otherwise was not bad at all.
PTG: Will you be participating in more competitions this year?
George: We plan to take this car to Louisville Midnight Mayhem and UW Stout Backwoods and even possibly Blizzard Baja. As well this car will go under intensive testing to get data on stresses that the different components are experiencing.
We wish them well on their upcoming competitions and are looking forward to continued partnership!
To see more about the team, visit their website at: http://www.northwesternbaja.com/