Upright functions: • Connecting hub for brakes, wheel bearings and A-arms • Allows wheels to move and steer through suspension travel Normal steering operating torque / forces depend on a number of variables. Although many metrics and details are reviewed during judging, it is easy to overlook various features which are critical to a given team’s efforts. The kingpin axis is the line between the upper and lower ball joints of the hub. Toe in is usually used in FSAE to improve stability at the cost of some tire wear Using new research and analysis This paper also gives us information about various load transfers under breaking, acceleration & impacts. Negative scrub radius (KPI/SAI line hits the ground outside of the center of the contact patch) imparts a toe in force on the tires. Scrub radius is the distance from the centerline of the tire/wheel to where the kingpin line intersects with the road surface. Rajendra Mane College SAE Team, MH08 Racing [2] give formulas for load transfer, breaking force & torque. Major Component – Wheel Upright. The FSAE car is a racecar purpose built for a prepared track, so performance and handling will be prioritized over smoothness and suspension travel. The upright was designed with minimal weight in … Recently I realized that changing the wheel offsets (or using spacers) to adjust the track width affects the scrub radius (a.k.a. This prototype is set to go on full production and is marketed towards the average weekend racer. Nick Butler, Grayden Elegante, Andre Romero, Spence Tan, Joel Williams. DESIGN While designing, the major factor is the type of geometry to be used for the steering system. Formula SAE is a student design competition organized by the SAE International. You might say “That is a matter o f course! This is typical of RWD cars. Mark Mark: "Bad Ast" Astro Van. The concept of FSAE is that each collegiate chapter assumes the role of a fictitious company who is set on building a prototype formula style race car. The only useful thing it does is help the driver to detect pull under braking, which may indicate he's on a split mu. Scrub radius It is the distance between centre point of contact patch and point where the steering axis cut the ground, the fundamental reason to take scrub radius is to feel the ride on steering wheel, but it has a problem regarding the large scrub radius will tends to increase the wear of tyre, hence (300 lb) car with very narrow, high pressure tires, at zero scrub radius, with zero KPI, and zero caster, lots of steering ratio, and the steering input force will be very small indeed, maybe as small as 1.3-2.7 Nm (1-2 ft.lb.). Budget Materials Cost = $322 Aluminum, Steel, Chromoly Tubing Parts Cost = $550 Bearings, Rod Ends, Spherical Joints, hardware Miscellaneous Costs = $100 Manufacturing Cost = ~$0.00 All fabricating was done by team in FSAE shop and student shop at no charge Total Cost = $972 Project Management The design of each component in the suspension assembly have been completed and optimized. You can build a 136kg (300 lb) car with very narrow, high pressure tires, at zero scrub radius, with zero KPI, and zero caster, lots of steering ratio, and the steering input force will be very small indeed, maybe as … Even solid axles have a scrub radius, it's just not really taken into account because it is moot. FSAE Suspension. Formula SAE® is a student competition, sponsored by the Society of Automotive Engineers (SAE), in which students ... and scrub radius. Rajendra Mane College SAE Team, … Each graph represents an effect that will be experienced during various driving events, such as roll, heave, or turning. Simulation results show that camber angle and scrub radius are beyond normal design range and require optimization. This creates a small tire/road friction resistance that in turn translates into feedback from the road. II. The design is weighed ... Scrub radius Toe angle . IRS have a scrub radius. Scrub radius helps this feel by providing feedback from the contact patch. These are the people that make the Rinehart PM100 motor controller that is well regarded in FSAE. Beyond steering feel, I'm suggesting that having the center of the scrub radius inboard of the KP axis (negative-scrub) or near coincident to the KP axis (zero-scrub) will provide the rumored ride height drop while turning the wheels. The choice of these parameters should be based on how the vehicle is expected to perform. Formula SAE 2010 Design Report I. FSAE Design Event Scoring (Some Insight into the Process) The design and developmental process of a FSAE car is a complex process. ... SAI and scrub radius. This car would be worthless to try and drive competitively as it would have a ‘dead’ The downsides of positive scrub radius that were discussed above would be considerably reduced thus giving more stable braking conditions and even wearing out the tyre lesser than it would have. The design and developmental process of a FSAE/FS EV car is a complex process. The scrub radius is the distance in front view between the king pin axis and the center of the contact patch of the wheel, where both would theoretically touch the road. I used the tire-calculator at Wheel-Size.com to compare the oem set up, (which assumed the oem set up had a zero scrub radius) to the new rims and tires and it calculated the new scrub radius to be positive 21/32″ scrub radius which is approximately 5/8″ or 16.67mm. This is typical of FWD cars. Looks like it'll have the power of the PM150 but it'll be smaller and lighter than the PM100. Figure Ten: Scrub Radius vs. Motion Formula SAE Hybrid Team 10. FSAE Design Event Scoring (Some Insight into the Process) The first thing to understand is that the design events are scored according to the criteria. With a small amount of scrub radius, the tire is turned about the kingpin axis, slightly offset from the tire’s centerline. If I was designing an FSAE car, I'd just get a rack with more travel, and run a higher steering ratio (ie, less handwheel torque). It could be positive, negative or zero. Engineering and Technology [1] , published research paper which shows information about Caster, Camber, Scrub Radius Keywords—FSAE; Upright; Soildworks; Ansys; Analysis; & kingpin inclination. which shows information about Caster, Camber, Scrub Radius & kingpin inclination. Positive scrub radius (KPI line or SAI line hits the ground inside the center of the contact patch) imparts a toe out force on the tires. The larger the distance, the more effort is required to turn the wheel, as the tire has to “scrub” slightly to turn around the kingpin … ... the brake rotor is on the inside of the upright also helps to minimize the scrub radius on our tire. So is judging! INTRODUCTION: Formula Student India-International Level Event, also known as FS-IND is a design competition which follows the standards of the prestigious Formula SAE/Formula … Suspension The first step to designing the suspension is picking out the ideal set up. Although many metrics and details are reviewed ... king pin inclination scrub radius, bump steer, and other geometry/kinematics? ... One of the safety components in the Formula SAE car is … The USQ’s FSAE team ran into some troubles in the FSAE 2007 competition when the race car crashed into the barrier due to inappropriate scrub radius and a sub-optimal steering system. Keywords: KPI, Camber, Caster, Scrub Radius, Roll Centre, Instantaneous Centre. Once you've got PAS scrub radius is a detail. caster trail, scrub radius and spring motion ratio, basically need to meet the overall vehicle targets. Scrub Radius. This paper also gives us information about various load transfers under breaking, acceleration & impacts. The three possible geometries that can be used are Ackermann, anti-Ackermann and parallel steer geometry. So is judging! Scrub Radius - posted in The Technical Forum Archive: One of my hobby cars is an old (1970) Lola formula ford. performance during judging and scoring. But ... inclination scrub radius, ump steer, and other geometry/kinematics? A negative scrub radius is suitable for vehicles with high power engine and a positive scrub radius offset for small power engines. bias the lateral weight distribution. Ive been experimenting with wheel offsets to a.) °Scrub Radius: With the scrub radius decreased from 33 to 20, a condition known as squirm will occur. ... Scrub Radius & kingpin inclination. 1. Setup optimization for the FSAE car MG07.12 Wheel loads estimate of a 125cc racing kart through on-track data acquisitions and numerical analyses Multibody analysis of the Formula SAE car MG0712 The scrub radius primarily affects the steering and In previous FSAE events from our college, the suspension design lacked in a solid methodology that will require time and resources. It is ... 2.50 in front 0and 2 in rear the requisite scrub radius was further calculated and plotted alongside Roll … scrub radius, mechanical trail etc. widen the track, and b.) In order to be deemed acceptable given the car’s restraints and the = Caster angle and mechanical trail Caster is defined as the angle between the steering axis and the wheel centerline extending perpendicular from the contact patch, viewed perpendicular to the side view (vertical longitudinal plane). The scrub radius is a product of the King Pin axis and the wheel/tire centerline or contact point at ground level. By visualizing the attitude of the car in a corner, the have to be kept in mind while designing and the best compromise for these values has to be found. Figure 8 - Diagram illustrating KPI and scrub radius 2 While caster, KPI, scrub radius, and mechanical trail are usually fixed once the suspension is designed, toe can be adjusted to add or remove straight line stabilizing effects. , Joel Williams the average weekend racer f course might say “ that is a complex process motor controller is. 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