Welcome
It looks like you're new here. If you want to get involved, click one of these buttons!
Stupidly ambitious project - day 2 / 100
-
Well hello all...... As some of you guys know, me and a friend from uni are attempting a rather foolhardy quest - to build a GP car in 100 days. Now then, we haven't worked that long on the car (this is the 2nd day of actual building)..........thought we might as well show y'all the project as it stands at the moment!
Arty shot of chassis as it is currently by Destiny Race Project, on Flickr
We'll be working to update this as often as possible!
What do you all think then?
By the way, if that didn't work, here's the album link:
http://www.flickr.com/photos/destinyraceproject/sets/72157625871029534/
Rob -
Looks like you are going to have fun :)
One thing though, you will need to have something more substantial than the white steps frame for a rollbar for safety. I would recommend an absolute minimum of 25.4mm diameter 1.6mm thick steel tubing (better to be wider or thicker than this). I suspect the steps white tubing is relatively thin. Also the shape of this should be able to take sideways loads so ideally should be a bit more triangular looking from the front (sloping in from the bottom). Its rear stays need to be at more of an angle (nearer to 45 degrees have a look at the regulations and some pictures and extra info in the forums on this). It also needs very strong mounting to the main frame at the bottom of the roll bar (which it can have in the above photo), at least 200mm up from the bottom of the rollbar and where the rear struts fasten to with the minimum number of small holes (if at all possible no holes).
Note that the cars can be 2.8m long so if you can find a longer ladder that would help as you all look relatively tall. Make sure there is at least 100mm from the top of your head "with helmet on" to the top of the rollbar, you will grow in 100 - 200 days ...
Good luck and have fun :) -
Hi Terry, thanks for the response and the advice! Luckily, the roll bar fits within your minimum specs - 32mm x 2mm, I think that the lighting makes it seem smaller......... one bit though - what do you mean about "Its rear stays need to be at more of an angle"?
We're planning to laterially re-enforce the rollbar by bolting some M10 bolts to it along with some steel plating, which is also where we'll mount the rear axle, do you reckon we'll have enough roll strenght then??
Many thanks
Rob
p.s. its all fun! -
I think terry means that the back legs of the stepladder need to be at a greater angle for strength and tocomply with the rules. Also, You need to check the position of the stepladder's back legs in relation to it's top.
"Roll bars must be firmly secured to the chassis of the vehicle. At least one triangulated brace must be fitted to the rear roll bar. This brace should attach to the chassis of the vehicle at one end, to not more than 200mm from the top of the roll bar at the other, and must be capable of taking forward and rearward loadings." -
You have the same target date as us and you're about as far on as we are - and we started in october!
Please read my comments about halfway down in this thread and have a think about if your roll hoop is really strong enough. I know you've provided dimensions but you can't know the quality of the tube and I've broken more than one ladder in the past - and that's without being particularly heavy (12 stone) and using the ladder as intended i.e. vertically rather than as a roll hoop. If you're at uni now there should be a tube bender somewhere on campus, and maybe even a department willing to order you some quality tube. I realise this will probably mean welding something sooner or later and I know how hard that is for a team with limited resources.
Using a ladder as a chassis is fine (as long as the roll hoop and seatbelts are well integrated), but as a roll hoop raised alarm bells as soon as I saw it. There are places to use parts like that, but not when it comes to safety. Chassis, roll hoop, seatbelts and brakes are places you do not cut corners.
Sorry to preach guys, don't want an injury though. -
Yes, as Cookie says, I meant that the rear struts should be at a greater angle to the vertical (less angle to the horizontal) than what it looks like in the picture. (Pictures can be deceiving, it looked like 20mm tube to me !). Something like greater than 35 degrees. The 2010 rules have some ambiguous diagrams on this (have they been updated ?) but there was some extra info in this thread from Greenpower admin: http://www.greenpower.co.uk/forum/comments.php?DiscussionID=1376
I did just try to download the rules to have a look, but the web site is broken for these links at the moment. -
Alright, so y'all think that the roll bar should be triangulated at a minimum angle of 35 degrees? Also, - Peter, how would you work out the infamous EI? We solidworksed it before hand and the stress analysis says that it should work, but would probably work better if (for example) filled with sand.
We'd just like to check with the community before we do anything entierly stupid......
Rob
P.s. Brian - lol, that would be so fun!!! -
If you're confident of the dimensions and think you've modelled it accurately (dimensionally, materially and in force input terms) in SW, you're 90% of the way there. Look in lots of detail (reduce the mesh size to 2mm or so) at the bolt holes in particular as the stress around there will be the point where it fails probably, and once the support bolts have given up supporting it, the hoop won't be far behind.
Have a good think about how you're going to attach it to the chassis, and try and model that joint in SW as well. In a rollover situation, the weight of the car will have to transmit itself to the roll hoop, either via the chassis connections or directly into the hoop (i.e. if you bolt your seatbelts directly to it). If you look at the hoop in isolation it's not really a fair test.
I don't think filling with sand would add anything significant other than weight - happy for any comments though. If I was worried about the strength of a roll hoop and aerodynamics weren't an issue I'd rivet some form of structural sheeting to it - either steel, ally or glass/carbon fibre - to act as a shear panel.
One day I'll get round to drawing some diagrams of all this because this isn't the first car I've seen that I wouldn't get in due to the roll hoop - it's just the first I've seen at this stage in the build so had the opportunity to give you my experience.
What uni are you at? -
Hi Peter, it does seem like you have a lot of experience, so please, preach away!! We plan to re-enforce the rollbar (which has now been lightly attached - using 6 M8 bolts - at a 45 degree angle) with some steel box section (3.75mm thick) around the base and as an auxliary A-frame, onto which we will mount the wheels. (the only problem now is drivetrain!!) The Solidworks was done at a fairly close-up view (10 mesh, i think, then teh computer crashed) and was of the rear section of the car.
We are both at Staffordshire Universtiy, doing media courses so therefore a good 20 miles from any discerable type of accesible machine shop -
Hi
I just want to say well done for taking this on, I think its great, added pressure makes the whole thing alot more fun. When we started out building M6 last year we had 6 weeks before we all went off for uni etc and it is so much fun spending that amount of dedicated time working on something. Still got a few bits left to go but will be ready for Silverstone.
I really like your use of materials to, uses the idea of "green" really well (that is if they are recycled). I really would take into account though what is being advised to you, I'm no expert but from what I've read these guys really are.
Good luck with it all and I look forward to seeing you on race day.
Dan -
Hi Dan
Much appreciated for the comments - the added pressure is also with us being in full-time education! Had a look on your Facebook page - M6 looks very nice!!
The ladders are partially recycled - the main one is an old one, the roll bar one is new - we didn't really want to risk rusty steel!!
Cookie - What sort of regualtions were you thinking of? Both myself and Tom are conversant with the regs and we can't think of any way in which we could be contravening anything......any chance of some pointers towards those niggly bits?
Photos coming soon!
Rob
