URracing
02-12-2008, 09:57 PM
So basically I just read through a whole discussion on new rules for 2009 in regards to the rear end configuration for Formula SAE. Just thought I'd post this to clarify a few questions I thought of while reading it.
So basically our car was started its design back in 2004 and now that we are on to designing the rear end and hoping to get the car into the 09 competition, I would like a few opinions on this topic. I am not going to explain the whole design on here since many of the you more experienced FSAE people are probably pretty busy with your own cars.
So basically we plan to use 1/2" aluminum plates to enclose the diff with a chain drive off the F4i motor. The original design was to use two different sized sprockets in competition - one small one for endurance and one larger one for the rest of the events where fuel mileage isn't an issue. I read we cannot swap parts in/out after tech so now we must design it to use one sprocket size and adjust fuel delivery for each event accordingly. The side plates allow for a solid diff mount yet slide fore/aft to initially tighten the chain and allow us to find the appropriate sprocket when testing the car before competition. (We will still include a spring-loaded chain tightener to keep the chain from "hopping"). In understanding the motor cannot be stressed, we must now create a rigid frame for the motor to just "sit" in.
My question is:
We plan to use one top and one bottom steel tube on each side, running along side the motor to attach the main hoop to the rear sub-assembly (aluminum side plates). Do we have to run these tubes all the way to the back of the car and weld them to the main hoop braces? or can we cut them off and attach them to the aluminum plates using appropriate thickness of plates *(such as with monocoque chassis - 3/16" I think) just rear of the motor? The top member we would like to be removable so the motor (or the entire rear end) can be removed easily.
To me, running the tubes all the way to the back defeat the structural purposes of the aluminum plates and therefore add unnecessary weight to the back of the car. Either way would ideally prove to be a rigid body but I'm just curious if there is anything I missed that would be against that in regards to rules or anything - especially for 2009.
While on this topic, for the 2009 competition, are we safe to run the driver's head under the main hoop or do we have to have the head rest in line with the hoop's plane - tough to get a tall driver in the car legally then http://fsae.com/groupee_common/emoticons/icon_frown.gif
Also, what is considered to be the rear most part of the car, the back of the tires or the frame (quick jack bar)?
Sorry for the long thread but your opinions and suggestions are most welcome. Good luck to all in the upcoming competitions. Hope to be at Michigan this spring to party while you are all fixing your cars http://fsae.com/groupee_common/emoticons/icon_smile.gif jk.
So basically our car was started its design back in 2004 and now that we are on to designing the rear end and hoping to get the car into the 09 competition, I would like a few opinions on this topic. I am not going to explain the whole design on here since many of the you more experienced FSAE people are probably pretty busy with your own cars.
So basically we plan to use 1/2" aluminum plates to enclose the diff with a chain drive off the F4i motor. The original design was to use two different sized sprockets in competition - one small one for endurance and one larger one for the rest of the events where fuel mileage isn't an issue. I read we cannot swap parts in/out after tech so now we must design it to use one sprocket size and adjust fuel delivery for each event accordingly. The side plates allow for a solid diff mount yet slide fore/aft to initially tighten the chain and allow us to find the appropriate sprocket when testing the car before competition. (We will still include a spring-loaded chain tightener to keep the chain from "hopping"). In understanding the motor cannot be stressed, we must now create a rigid frame for the motor to just "sit" in.
My question is:
We plan to use one top and one bottom steel tube on each side, running along side the motor to attach the main hoop to the rear sub-assembly (aluminum side plates). Do we have to run these tubes all the way to the back of the car and weld them to the main hoop braces? or can we cut them off and attach them to the aluminum plates using appropriate thickness of plates *(such as with monocoque chassis - 3/16" I think) just rear of the motor? The top member we would like to be removable so the motor (or the entire rear end) can be removed easily.
To me, running the tubes all the way to the back defeat the structural purposes of the aluminum plates and therefore add unnecessary weight to the back of the car. Either way would ideally prove to be a rigid body but I'm just curious if there is anything I missed that would be against that in regards to rules or anything - especially for 2009.
While on this topic, for the 2009 competition, are we safe to run the driver's head under the main hoop or do we have to have the head rest in line with the hoop's plane - tough to get a tall driver in the car legally then http://fsae.com/groupee_common/emoticons/icon_frown.gif
Also, what is considered to be the rear most part of the car, the back of the tires or the frame (quick jack bar)?
Sorry for the long thread but your opinions and suggestions are most welcome. Good luck to all in the upcoming competitions. Hope to be at Michigan this spring to party while you are all fixing your cars http://fsae.com/groupee_common/emoticons/icon_smile.gif jk.