senior project

[coldmm803]

I’m a senior in college and will be graduating on May 17th with a BS in Mechanical Engineering. In order to graduate we have to do some form of senior project and I was allowed to do the SAE (society of automotive engineers) Mini Baja. Basically, I get to build a dune buggy with a group of 4 other people (because my school is small, there is a total of 15 Mech E students). Some other schools I’ve seen info about have 10ish team members.The goal of the project is to design, build and test an off road vehicle. We will be competing in the East event (May 1-3) in Tennessee this year and each East event contains a water portion. We will be leaving around 3am Wednesday 30th to drive down to Tennessee and competing against 92 other teams from around the world (India, Colombia, France and several other countries). The water obstacle makes it necessary for the vehicle to be able to float and propel itself along with going over logs, through mud and other obstacles. A car, float??? Yea, apparently it is possible.My team members and I have been working on this since September and here are a few pics from our progress throughout that time from the photobucket links below. This project has been my hell and lead to many 10hr days just working on the project + class…and sleep.http://s37.photobucket.com/alb...t=allBuilding the car. We work at the sponsors company which is a power plant so we’re supposed to wear hard hatsOur first set of tubes welded together

[coldmm803]

Engine is given to us by SAE and is a Briggs and Stratton 10hpFront suspensionBox on the sides are full of foam for flotation, there’s also foam behind the seat and below the engine. This is the foam they use in boats Rear suspensionCVT and gearingHere are a few pics that I got yesterday from testing. From the link above, you can go to the testing run 3 folder for more picsIt floats!!!Still floats with the weight of a 180-200lb driver. The person standing in the water is about 6’3” to give you an idea of how deep the water is.The front end of the frame is open allowing water in thus more weight to the vehicle and causing it to float lower in the water. We will be blocking this off tomorrow.My batteries then died so I missed some of our other testing but was able to get a video of the car going up and over a hill. The hill is pretty steep and was very hard to walk up or down, our advisor fell twice going down it.After testing, its time for a bathVideohttp://s37.photobucket.com/alb...3.flv

[audiovibe]

That thing is pretty sweet, what are you guys doin with it after the competition?Aron

[coldmm803]

thanks. after competition it will sit at our school on display

[WaveAction]

thats pretty sweet..my buddy tried to build a dune buggy once..but failed lol..awesome how it floats even with an extra 200 lbs or so in it

[kevera]

That's awesome,good work man.Hope you get a good grade on it.

[lovemyraffe]

That's freakin awesome! And it floats!

[tribalman]

good luck in the contest! awesome build.

[TraySeeLea]

Looks neat...I know a lot of engineering schools in NY build snowmobiles and things.Good Luck!!

[MRCN RCE]

Quote, originally posted by lovemyraffe »That's freakin awesome! And it floats!Quote, originally posted by tribalman »good luck in the contest! awesome build.+1are you guys going to put foam in the front section too?? that alone should help the front end stay out of the water. just my .02

[coldmm803]

thanks guysMRCN, yea we do plan to put some more foam in the front.TraySeeLea, i've heard about the snowmobile competitions but we dont get a whole lot of snow here and we do senior project as a full year thing so they it would have to be started much earlier and Widener U isn't organized enough for that

[waveresponder]

good luck!....looks awesome!

[coldmm803]

Got back yesturday from Tennesse and competition. Things didn't go as well as we had hoped had some issues with our gearing and rear axle.I'll make a full post with details later in the week when i have time. I have a final on Wednesday that i have to start studying for/ going over the review sheet

[engineertwin2]

Congrats on racing! I did the Mini Baja in 2003 and 2004, but only competed in the western competition based on our geographic location and distance to the eastern events.The first time(s) around, it never goes as planned, but it's fun to compete and see how others solved the same problem.I'll dig up pictures of our Mini Baja's if I can find em.

[coldmm803]

thanks engineertwin, i'm a senior and as the title states it was my senior project so i wont be able to build another If i got to do it again, i'd put in a differential so the rear tires could rotate at different speeds and decrease our turning radius. during the suspension and traction event we got disqualified because we went outside of the flags but it was because our car couldn't possibly make the turn. having a differential would also help becuase it would offer a gearing reduction and we may have been able to get rid of some or all of the gears we used. from the pics in post 2, the little gear on the end of the one shaft caused a lot of problems.Are you a Mech Engr? What company do you work for, what do you do?

[engineertwin2]

I'm a mechanical engineer working for a power utility in the Phoenix Metro area. I can't see your pics at work, but I will check out what you mean later.Our first iteration had an open differential and proved to be advantageous for maneuverability. However, the west competition substitutes a rock crawling and/or hill climb event for the floatation event. The differential proved to be extremely cumbersome (even with cutting brakes - hand brake that control each rear wheel brake individually).Given the need for some pretty extreme rock crawling (boulders that were 1/4 of the size of the vehicle) we opted out of the differential for the second vehicle.Also, we opted for a snowmobile CVT to provide optimal "automatic" gearing with minimal input. We did have a Forward - Neutral - Reverse transmission feeding the CVT output drive, but the shifting mechanisms required significant modification and upgrades given our team members' inability to shift while completely stopped.

[engineertwin2]

Ok, I got to see your pics. Looks awesome! Here's how ours turned out way back in 2003.Me test driving the vehicle - taken straight from a video camThe reason the car had headlights - most of our build and test was at night.The NAU mini-baja at BYU in Provo, UT ready for competition.The team group photo. It was odd. There were only a couple of us building the thing, but more people showed up for the competition. I'm the goofy guy in glasses sitting on the wheel on the right side of the photo.The much improved ground clearance of the 2004 NAU mini baja. We went from not clearing the rock crawling to even the dumbest driver on our team could make it through no sweat.Front view of the 2004 NAU mini baja. I wish I had some finished pics of it - I can't find them anywhere. Also, NAU means Northern Arizona University.

[hskater26]

damn that things sick....nice job

[coldmm803]

The update that i've been putting off cause i'm lazy but have been kinda busy too.first day of competition had possible events of tech inspection, brake test and float test. in order to do the brake test or float test you had to pass tech. Tech inspection was just that, an inspection of the car to make sure we followed the rules. We went thru and they had a few issues with things but nothing real major. we had to add a few short tubes to the frame, redo the seat belt mounting (we mounted the belt the same way the previous team did but that was no longer acceptable) and weld in a few bolts that didn't have nylon lock nuts on them (even tho they were OEM atv hardware/assemblies). We got to the brake test late in the day and were unable to lock up all 4 wheels on the pavement, the front locked up no problem but the back wouldn't. We tried a few times but nothing worked. Events then closed for the day.2nd day. We continued with the brake test and eventually passed after a bit of tinkering with stuff. We then went on to the float test and passed with no problem. Throughout the 2nd day there were events that tested the technical aspects of the cars such as water manuverability, suspension and traction, and a sled pull.The first tech event that we did was the sled pull. We let Chad drive and i dont know why, this kid is an idiot and i dont know how his grades are higher than mine. As mentioned in the vid, he stops during the first run to ask if he should keep going since the chain was clicking. In the end we didn't get any points for the sled pull because we didn't pull enough weight.link to vid: http://s37.photobucket.com/alb...l.flvI was the driver for the float test and water manuverability since i was the lightest member on the team. In the end, we didn't get any points for this either because we didn't complete it quick enough. apparently you have to be within 2.5x the quickest team. the quickest team some how did the course in 46seconds, so we needed to be under 2minutes. guess we should have made fenders for the back tireslink to vid: http://s37.photobucket.com/alb...s.flvFinal event was the suspension, as you will see in the video, the chain jumped off during the first run and we got stuck. We fixed that and went back for the 2nd run. We ended up getting disqualified because we took a turn too wide and went outside the flags. Our car couldn't physically make that turn, its not possible due to our turn radius. So, once again, we got 0 points.link to vid: http://s37.photobucket.com/alb...n.flvI guess that endo coming off the hill during the 2nd run was bad for the bearings, since the bearing shattered...after we finished the event3rd day endurance race. They did a water start which was pretty cool. We made it about half a lap and then the keyway's on the universal joints slid out and the back end locked up. We ended up welding them in place and went back in. We didn't get any further, we shattered another bearing, this time on the right side. We didn't have any more there with us so we rigged stuff together and that wheel flopped around like a fish but we tried to continue a 3rd time. Once again we broke at basicly the same spot, this time, we sheared the ear off one of the universal joints. Since everything was welded together on the axle we couldn't fix it and our race was over. I don't have any videos of these break downs but do have a few of the random points in the race and i'll post links for them when i get a chance to merge parts together and shrink the vid size. My batteries were dead but i was able to get little bits every now and then.heres a few links to other schools vids on youtube, you can check the related video's and if it was posted this month then it could be from the event we went to at Tennessee Tech U (TTU)http://www.youtube.com/watch?v=vEnj9omE ... ?v...lated

[coldmm803]

thanks for the pics engineertwin2, looks good. i like that last pic with the wheel on the table

[engineertwin2]

Thanks! The endurance event truly is an endurance race. My first year, our car died about 2 hrs into the 4 hr race when another car T-boned us coming off a jump right in the rear wheel - completely killed the left side rear suspension (CV joints, a-arms, shocks, etc). We would've complained but the same thing happened to about 20 other cars - it was just bad course design.2nd year we made it literally 3hrs and 45 minutes of the 4 hr race before we broke down - it was pretty heartbreaking thinking we'd make it to the end and lose it with just 15 mins left.The 3rd year (I didn't participate), they lasted about 40 minutes, so endurance really is a tricky thing.Glad to hear you guys eventually passed inspection. We solved the turning radius issue with cutting brakes the first year, but just dealt with it the next few years. Cutting brakes are definitely worth it.