Suspension The first step to designing the suspension is picking out the ideal set up. ... One of the safety components in the Formula SAE car is … 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 Formula SAE is a student design competition organized by the SAE International. Normal steering operating torque / forces depend on a number of variables. Major Component – Wheel Upright. By visualizing the attitude of the car in a corner, the ... the brake rotor is on the inside of the upright also helps to minimize the scrub radius on our tire. performance during judging and scoring. In order to be deemed acceptable given the car’s restraints and the A negative scrub radius is suitable for vehicles with high power engine and a positive scrub radius offset for small power engines. 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 … It could be positive, negative or zero. Scrub radius is the distance from the centerline of the tire/wheel to where the kingpin line intersects with the road surface. Although many metrics and details are reviewed ... king pin inclination scrub radius, bump steer, and other geometry/kinematics? 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. Scrub Radius. Ive been experimenting with wheel offsets to a.) widen the track, and b.) (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.). FSAE Suspension. 1. 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. This is typical of RWD cars. Formula SAE® is a student competition, sponsored by the Society of Automotive Engineers (SAE), in which students ... and scrub radius. Even solid axles have a scrub radius, it's just not really taken into account because it is moot. bias the lateral weight distribution. Part 2: https://youtu.be/oh535De4hKgSprings and Anti-roll bar video: https://youtu.be/NFGkZNrNTIE 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). Using new research and analysis The only useful thing it does is help the driver to detect pull under braking, which may indicate he's on a split mu. 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 Keywords: KPI, Camber, Caster, Scrub Radius, Roll Centre, Instantaneous Centre. The objective of this senior project is to design and optimize the suspension for FSAE and develop a process that future teams can follow. Scrub radius helps this feel by providing feedback from the contact patch. This paper also gives us information about various load transfers under breaking, acceleration & impacts. 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 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. °Scrub Radius: With the scrub radius decreased from 33 to 20, a condition known as squirm will occur. Rajendra Mane College SAE Team, … Each graph represents an effect that will be experienced during various driving events, such as roll, heave, or turning. DESIGN While designing, the major factor is the type of geometry to be used for the steering system. This prototype is set to go on full production and is marketed towards the average weekend racer. In previous FSAE events from our college, the suspension design lacked in a solid methodology that will require time and resources. The design and developmental process of a FSAE/FS EV car is a complex process. So is judging! 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. Recently I realized that changing the wheel offsets (or using spacers) to adjust the track width affects the scrub radius (a.k.a. Rajendra Mane College SAE Team, MH08 Racing [2] give formulas for load transfer, breaking force & torque. Nick Butler, Grayden Elegante, Andre Romero, Spence Tan, Joel Williams. 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. The three possible geometries that can be used are Ackermann, anti-Ackermann and parallel steer geometry. This paper also gives us information about various load transfers under breaking, acceleration & impacts. o Have peak loads been determined and designed for? have to be kept in mind while designing and the best compromise for these values has to be found. Formula SAE 2010 Design Report I. Simulation results show that camber angle and scrub radius are beyond normal design range and require optimization. So is judging! These are the people that make the Rinehart PM100 motor controller that is well regarded in FSAE. = Engineering and Technology [1] , published research paper which shows information about Caster, Camber, Scrub Radius Keywords—FSAE; Upright; Soildworks; Ansys; Analysis; & kingpin inclination. This car would be worthless to try and drive competitively as it would have a ‘dead’ scrub radius, mechanical trail etc. The design is weighed ... Scrub radius Toe angle . II. 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. 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 … 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 … The upright was designed with minimal weight in … This clearance issues are probably why FSAE cars typically run high scrub radius' in the first place (although it does nice things for jacking). The scrub radius is a product of the King Pin axis and the wheel/tire centerline or contact point at ground level. You might say “That is a matter o f course! Looks like it'll have the power of the PM150 but it'll be smaller and lighter than the PM100. This is typical of FWD cars. which shows information about Caster, Camber, Scrub Radius & kingpin inclination. But ... inclination scrub radius, ump steer, and other geometry/kinematics? IRS have a scrub radius. 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 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. 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. 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. Mark Mark: "Bad Ast" Astro Van. Furthermore, the kinematics of the suspension, such as roll centre height, track gain, camber gain, caster gain, Ackermann change with steering angle, roll steer and bump steer, also need to be verified. It is ... 2.50 in front 0and 2 in rear the requisite scrub radius was further calculated and plotted alongside Roll … 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. 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. The choice of these parameters should be based on how the vehicle is expected to perform. 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. The FSAE car is a racecar purpose built for a prepared track, so performance and handling will be prioritized over smoothness and suspension travel. 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. Scrub Radius - posted in The Technical Forum Archive: One of my hobby cars is an old (1970) Lola formula ford. This flaw demonstrates the importance of correct suspension parameters in the handling ability of the car. 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