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I know there are still a lot of sceptics out there so I thought it would be a good time to devote a thread entirely to wings. Here at Monash we are completely convinced of the benefit of wings, even with the low speeds encountered in FSAE, but we'd love to hear everyone else's thoughts on the topic.
Regards,
Scott "Maverick" Wordley &
Roan "Goose" Lyddy-Meaney
MOnash FSAE Wingmen
Roan and I have spoken before about wings, so you know that we are also supporters of winged FSAE cars. Posts from late summer concerning the Solo II nationals from Dr. Woods, Ken Hassler, and the alumni from Cal Poly Pomona show their ideas about wings as well.
The trick is to get a winged car under 500 lbs. Our car and UTA were the first to have suspension mounted wings, theirs was over 500 lbs by a bit (530ish), ours was just under (497). The year before with chassis mounted wings, both our cars were under 500.
We don't have any wind tunnel data on our wings unfortunately, just CFD, but have driven with and without, and seen considerable differences in available grip.
www.formularpi.com
Yeah, our car was a bit overweight at 270kg (594lb), so that's something we need to focus on for the new car.
But we found that the wings more than made up for all that extra weight.
Regards,
Scott "Maverick" Wordley &
Roan "Goose" Lyddy-Meaney
MOnash FSAE Wingmen
Personally, I think a winged car done right will be faster than a wingless. But it's very difficult and very time consuming to do wings the right way. I compare it to NA vs. turbo engines in the competition. Yes, you can make more low-end power with a turbo and that makes it better. However the complexity and time required to make everything click just right make it difficult to justify the project to teams trying to budget time effectively. I see wings as the same.
Auburn was one of the few teams running wings in the late 90's. In fact I think we were the only winged team in 1999. The 1999 car was a 2nd year car, except the 1998 version was wingless. The 1999 car was faster in the endurance event, probably helped by the wing (which was active, and electropneumatic). However the extra weight hurt all the other driving events, as well as design and cost.
I think a winged car can be faster in the endurance event easily. But it would have to be an excellent setup to overcome the problems in skidpad and acceleration (and in the US, autocross. Seems like the other autox events are a lot faster).
Add in the extra time involved, and that is why we don't have a winged car. But like turbos, I'd love to try it someday, and I think there are benefits to be had.
-Charlie Ping
Auburn University FSAE 1999-present
Actually the Australian autocross track which we just competed at was one of the slowest tracks ever (according to Carroll Smith), yet we still managed to gain an advantage.
The only way to make wings work in this competition is to aim for the maximum possible downforce. The maximum possible area of the wings is limited by the rules, so the only possible way to increase downforce further is to increase the CL. The way to do this is to run multi element wings. I think that three elements is the minimum anyone should consider using. I still can't understand why teams like Cal Poly Pomona are using single element wings. It's not much more work to build multi-element wings and the gains from it are huge.
The quest for downforce doesn't stop after front and rear multi-element wings have been designed. The next logical step is to buld sidepod diffusers. The downforce from these is somewhat limited due to the small floorpan area for the negative pressure to act over, but every little bit counts. As well as the wings and the side diffusers we also ran a very large rear diffuser (first team ever worldwide to our knowledge).
Charlie, I had a look at your website to check out your winged cars and I am still struggling to understand the logic behind the design. Our rear wing alone was at least as big as your single wing and ours was a four element wing which gave us around half of our total downforce. And judging from the angle of the wing in the pictures it looks well and trully past the stall angle.
The only way to make wings work in this competition is to make them BIG.
Regards,
Scott "Maverick" Wordley &
Roan "Goose" Lyddy-Meaney
MOnash FSAE Wingmen
What was the fastest Austrailian Autocross time?
To answer your questions, I had nothing to do with the wing design as it was done in 1997. The same wing was used in 1999, with the pitch active (throttle position activated). I joined in 1999 after competition, and only 1 1999 member returned in 2000. So little knowledge was passed on.
Like I said, I believe that wings can be an overall benefit, but the time spent on them will likely be better spent on something else, depending on your team's situation of course. If you have the capability and workforce to work on wings it's a worthwhile project to look into.
Until then we will work on the basics, like weight, power, and refinement in all areas.
-Charlie Ping
Auburn University FSAE 1999-present
I checked the results, 39 second AutoX times. Detroit's best time was a 75. What was the length of the course in Australia?
-Charlie Ping
Auburn University FSAE 1999-present
From memory the autocross track was about 450 metres. The fastest time was actually 34.89
Regards,
Scott "Maverick" Wordley &
Roan "Goose" Lyddy-Meaney
MOnash FSAE Wingmen
Hey everyone,
Props to the boys down under for starting this thread.......
For what its worth, you guys answered your own questions about aero configurations.
In fact, you touched on the core question of the FSAE competition.
Mods such as forced induction, aero, composite chassis, engine (I could a had a V8) etc... are all worth it IF you can justify the performance improvement against time, resources, skills, and interest. Interest being the key here!! If you believe that something will work strongly enough, you can make time to gain skills and resources.
So lets compare what I currently see as the two ends of the aero spectrum: Cal Poly Pomona 2000 vs. UTA 2002. (BTW, I like MOnash's 02 car but don't know enough about it) Both teams shared intense interest in making aero work, and had VERY well established infrastructure and resource bases.
Specs:
Cal Poly
Ø Low Speed, High Lift, Single Element Wings (30 sq. ft. worth)
Ø Development Requirements: Undergrad (Junior) Level Research Project For Airfoil Selection, Wing Integration, and Construction
Ø Chassis Mounted design (total weight 50 lbs...ouch)
Ø Construction: fiberglass skin, foam core, vacuum bagged wings wood end plates, aluminum tube mounts. (all built in the lab on campus)
Ø Performance 250 to 350 pounds down force @ 60 mph (based on test data) increase of .25-.50 lateral Gs on endurance course in Detroit and sustained 2+ lateral Gs on SCCA courses
Ø Pros: simple design, simple construction, rapid prototype, simple to tune, better low speed performance
Ø Cons: dynamic sprung weight, lower efficiency, high CG, not as esthetically pleasing (i.e. design points)
UTA (Ken please chime in if I'm too far off on this)
Ø Multi Element front and rear wings with under body tunnels
Ø Development Requirements: Graduate Level development utilizing CFD for wing element placement and tunnel integration.
Ø Suspension Mounted design (total weight about 30 pounds...nice job)
Ø Construction: Carbon Fiber, Hollow Molded wings and under tray. Construction care of professional composite fabricator (gotta find and reel in those industry sponsors!!)
Ø Performance (according to UTA drivers) .3 g increase in cornering in Detroit .50 or more on faster courses (i.e. SCCA events)
Ø Pros: Downforce directly to tires, low CG, potentially more efficient, lighter, MUCH more aesthetically pleasing (i.e. design points)
Ø Cons: Highly Complex to develop, construct, and tune, questionable low speed performance.
So which car is a better design...IMO: UTAs 02 car was a better overall design than Cal Poly's 2000 car
The UTA car was lighter (70 pounds or more), smaller, better integrated, and better prepared when the two competed at SCCA Nationals in 2002.
On a side note, UTA did poorly in Detroit for 02 (the car broke) but beat the Cal Poly Car (3rd place in Detroit 2000) at Nationals in 02 after further development and tuning.
OK so there is a base line for all you up and comers out there, and in my opinion, a team should not even attempt aero unless they have a proven existing car design to build from, and DRIVERS, DRIVERS, DRIVERS!!!!!!!!! Without those things you will not be done with your car in time to practice and will not have the skills to drive it, let alone tune it, so you might as well stay home thus avoiding being laughed at in Detroit while your pushing your broken race car off the course after leading the endurance race..... (or so I've heard nudge, nudge, wink, wink, sob, sob)
My two cents on Aero implementation (and the car in general):
1. Keep It Simple (small steps grasshopper...) the difference in performance between the above examples was more about total weight, size, and engine performance than aero (UTAs Aero was better IMO but not enough better to discount Cal Poly's approach.) Unless you have the time and resources to design and VALIDATE a complex aero package, forget it!! A simple wing addition to the car can be just as effectively as tunnels, multi elements, suspension mounting bla bla bla.....
2. Make sure you understand the impact of performance upgrades to the car, whatever they may be. Unless you can justify your upgrade will allow your drivers to go faster (not make the car theoretically faster) don't do it. Therefore it's all about research and testing.
3. Don't reinvent the wheel, but worse yet, don't buy into what someone else has done as the absolute. Ultimately it comes down to the standard engineering answer to any technical question (usually from management or worse yet....marketing)
So in this case....Do Aerodynamics work on FSAE cars??????
"IT DEPENDS"
In Closing, I would like to ask UTA to post the G circle data from Nationals in 2000 and 2002 (i.e. wings vs. no wings on similar (BUT NOT THE SAME!!) car) Given the speeds at Nationals, I don't think this info is proprietary. BTW, the G circles for Cal Poly, UTA and one of the A-mod cars from 2000 Nationals are on the web somewhere....
Keep it up everyone, you help us old guys stay young
Cheers,
Wingman
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Dominic Venieri:
Our car and UTA were the first to have suspension mounted wings, theirs was over 500 lbs by a bit (530ish), ours was just under (497). <HR></BLOCKQUOTE>
I just re-read this post, and I've got to add that Auburn University had a suspension mounted wing in 1997 and 1999.
-Charlie Ping
Auburn University FSAE 1999-present
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