The benefit of wings fixed on thesuspension

[old soldier]

sorry for my carelessness?it's 200N

Originally posted by Racer-X:
If the aero teams need to do that then the non aero teams need to have a donut cook off.

[old soldier]

We have use aero for two years?last year we mount front wing and undertray on Monocoque?half monocoque? ?and rear wing on rearbox ?when we went to FSAE Japan?I saw lots of them use unsprung rear wing?so when we begin 2013?we want to use unsprung but without certain reason just folow the trend.Forgive my ignorance.by the way,if there is some papers talk about this theme?

Originally posted by Dunk Mckay:
Someone more experienced than I in these matters has kindly pointed out to me that excessive suspension travel (bottoming out) due to high downforce loads is another reason to mount unsprung aero. The quick solution to this of using stiffer springs will then have a direct (potentially negative) affect on vehicle performance.

As mentioned above it is a heck of a lot easier to mount wings unsprung. In the case where bottoming out is your main issue, then mounting wings upsrung to reduce the aero load transmitted to your springs may be a good solution, especially if you are struggling to come up with a reliable, reasonably lightweight solution for mounting a stiff undertray to your uprights.

With regards to the one wheel bump problem, Bemo, I would question how often you are going to encounter this case. It will mostly depend on the tracks that your car is going to run on. If it's a rare occurrence then you might consider how important it is over the other gains. However if you're bumping up apexes (apii? :P) every other corner then you should probably look into it a lot and either keep things simple and mount your UT sprung, or try and figure out a really clever way to have it mounted to all 4 uprights, but if one wheel starts acting different to the other it only has a small or now effect on the position of the UT. I'm sure them some solution for this, even if it depends on lots of fancy electronics. You just have to decide how capable you are at working al of this out and applying a solution.

Personally I'd keep things simple. If your team have not run aero much before then go sprung for ease of design and manufacture. If you have then you should be able to identify the limitations of your existing designs and how going unsprung would likely affect you performance.

[jordan.k]

With the integration of an unsprung undertray and wings attached at the lower A-Arm, it sounds very similar to a twin chassis. Very similar to the Lotus 88 and the 2012 SDSM&T car.

[jlangholzj]

As much of a push as it was to get there, SDSM&T had a relatively successful season with an unsprung aero package. I can't attest to any of the gains in running suck a package but it is possible. I think they had a showing of 4th in auto-x at michigan.

[old soldier]

I think fix the aero on upright is such a difficult thing for us?I just want to fix the rear wing unsprung?thank you for your advice

Originally posted by Bemo:
At a track like at Hockenheim I'd say you really should consider the bump problem. All I wanted to say is that in such a case you have to consider carfully what impacts such a design has on the suspension behaviour. It will link all four wheels somehow and it will have some effect.
The question you have to ask yourself is how much will downforce increase compared to a sprung undertray and if it is worth it to design such a system.
Another design difficulty not mentioned yet is that you have to attach the undertray to the front uprights in a way that the aren't affected by steering. It would be propably easier to attach it to the outside point of the lower A-arm. With all the packaging constraints you usually have there that's not the easiest task.
I don't say it's impossible, but quite a lot of pain in the ass you have to consider.

[Dunk Mckay]

Ok, taking all other ideas and variations out of the equation then...

I think you just have to consider how much more complicated and costly it's going to be to design and built uprights and connected supports that you can mount your wing to. Uprights are relatively small so you're going to end up with a fairly high bending moment at the base of the support arms seeing as you can't triangulate very much. This can be designed for of course, I'm not sure about semi-unsprung wings, I guess you could have a longitudinal 'tether' to the back of your roll hoop and "vertical" struts down to the uprights and eliminate this problem while still sending all you downforce straight to the uprights.

It's mainly going to be the complications in the upright, keeping them stiff, packaging properly, etc. If you've got 13" wheels this should be a lot easier.

[Bemo]

Just saw on the FS Total Facebook Page that UWA is running an unsprung undertray this year. Definitely nice work. Taking a look at that pic you can see, that it is definitely not that easy.
I hope they'll come to Hockenheim with that car next year. I'd really love to see it running first hand!

[Zac]

Originally posted by Bemo:
Just saw on the FS Total Facebook Page that UWA is running an unsprung undertray this year. Definitely nice work. Taking a look at that pic you can see, that it is definitely not that easy.
I hope they'll come to Hockenheim with that car next year. I'd really love to see it running first hand!

Also looks like a space frame this year.

[Lorenzo Pessa]

Really few pics.
It's a little bit unusual the solution they use for cooling. the fan is mounted at the beginning of the radiator inlet duct.
We have to wait few days for competition pics.

[rjwoods77]

Just some notes to gleen if you were to do it. Notice the watts link for the struts....

http://www.rotaryeng.net/Chaparral-2F.pdf