Post your DIY aero pics
#781
It's not uncommon to see poorly attached spoiler/splitters "pumping" (sucked to the ground and then back up again when the df is lost) and then giving quite a varying result.
Flex can be used as an advantage, if you know what you are doing, so it's much easier to keep things firm.
Many hobby racers get really surprised when aero actually work (diffusers ripping pop-rivets etc).
Flex can be used as an advantage, if you know what you are doing, so it's much easier to keep things firm.
Many hobby racers get really surprised when aero actually work (diffusers ripping pop-rivets etc).
#782
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jpreston - Thanks for pointing that out. I had to go back and refresh my memory on force/energy in elastic deformations. Sometimes it's easy to fall into the trap of repeating what you've heard a million times. The misconception is not confined only to forums or to the amateur level, I've seen this 'knowledge' reiterated by guys involved in IMSA, Grand Am, etc.
There are other negative effects of flex due to downforce, as Leafy and NiklasFalk have touched on. I've heard of diffusers deforming to the point of becoming completely ineffective, and have seen several examples of deformation at speed completely changing the profiles or attitudes of parts.
On a pro level flex can be intentional and tuned - wings decreasing aoa and rear bodywork depressing to reduce drag (LMP), winglets deflecting to shift the center of pressure (F1), etc. etc. but on an amateur level it is almost always unintentional and detrimental except for a few specific cases I can think of where it was cleverly used to a benefit, albeit a blunt one.
The other ugly byproduct that can arise in aeroelasticity is 'flutter' or oscillations, and this is in nearly every instance detrimental.
So for more than one reason, it is ideal to fix aero components as solidly as possible.
-Ryan
There are other negative effects of flex due to downforce, as Leafy and NiklasFalk have touched on. I've heard of diffusers deforming to the point of becoming completely ineffective, and have seen several examples of deformation at speed completely changing the profiles or attitudes of parts.
On a pro level flex can be intentional and tuned - wings decreasing aoa and rear bodywork depressing to reduce drag (LMP), winglets deflecting to shift the center of pressure (F1), etc. etc. but on an amateur level it is almost always unintentional and detrimental except for a few specific cases I can think of where it was cleverly used to a benefit, albeit a blunt one.
The other ugly byproduct that can arise in aeroelasticity is 'flutter' or oscillations, and this is in nearly every instance detrimental.
So for more than one reason, it is ideal to fix aero components as solidly as possible.
-Ryan
#783
Another reason flex should be avoided at our level is that, in general, any part allowed to flex will eventually fail. The pros that are designing significant flex into aero components are also calculating cycle life and throwing parts in the trash after a certain number of hours.
#784
the delta wing is copping us.
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#785
If you were going to make one of the "EP" styled air dams out of aluminum sheet, what thickness would you choose? It seems Emilio prefers 0.100" HDPE, so aluminum I should choose something <0.100"?
Last edited by Efini~FC3S; 01-21-2015 at 12:40 PM. Reason: Ask a question? Use a question mark!
#786
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Anything close to 0.100 would be ridiculously heavy. In basic sheet form, there's a fine line between lightweight and too flexible with aluminum. Why would you want to use aluminum anyways? These aren't dirt circle track cars, think beyond just sheet metal options, ABS is much better in this application.
-Ryan
-Ryan
#787
Anything close to 0.100 would be ridiculously heavy. In basic sheet form, there's a fine line between lightweight and too flexible with aluminum. Why would you want to use aluminum anyways? These aren't dirt circle track cars, think beyond just sheet metal options, ABS is much better in this application.
-Ryan
-Ryan
Aluminum is a poor choice for EP style dam. Thick enough to resist dents and its both hard to work with and heavy, besides costing more. HDPE is flexible, super easy to work with, reasonably light and most of all, dirt cheap. I buy mine from Amazon, All Star sheet plastic.
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#788
Will be testing this aero package next weekend. Large front and rear spoilers, and fastback. Will make side skirts if I get time.
image hosting 30 mb
image hosting 30 mb
#789
Agreed.
Aluminum is a poor choice for EP style dam. Thick enough to resist dents and its both hard to work with and heavy, besides costing more. HDPE is flexible, super easy to work with, reasonably light and most of all, dirt cheap. I buy mine from Amazon, All Star sheet plastic.
Aluminum is a poor choice for EP style dam. Thick enough to resist dents and its both hard to work with and heavy, besides costing more. HDPE is flexible, super easy to work with, reasonably light and most of all, dirt cheap. I buy mine from Amazon, All Star sheet plastic.
So...I'm definitely going to use Aluminum, just don't know what thickness to use.
#791
Link to rules?
I'd suggest a thin skin, .049 or maybe .030 with supports underneath. I think it's uncharted territory though since no one ever bothers with al for that structure. You will eventually become the expert and tell us what does and doesn't work.
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#793
What organization and class?
Link to rules?
I'd suggest a thin skin, .049 or maybe .030 with supports underneath. I think it's uncharted territory though since no one ever bothers with al for that structure. You will eventually become the expert and tell us what does and doesn't work.
Link to rules?
I'd suggest a thin skin, .049 or maybe .030 with supports underneath. I think it's uncharted territory though since no one ever bothers with al for that structure. You will eventually become the expert and tell us what does and doesn't work.
Homemade aero is allowed on a point per sq-ft basis.
Wood (up to 0.5" t) = 1pt / sq-ft
Sheet Steel or Aluminum (up to 0.25" t) = 2pts / sq-ft
Sheet Plastic or Polycarbonate (up to 0.38" t) = 3pts / sq-ft
Carbon Fiber = 5 pts / sq-ft
Points are few and very precious. Since plastic is 150% the point cost of aluminum I thought I'd try aluminum for the air-dam and rear spoiler. Some sort of splitter will be made out of wood.
So it's not that the rules don't allow plastic, just that they favor aluminum.
Last edited by Efini~FC3S; 01-21-2015 at 07:35 PM. Reason: I spelled splitter "spoiler"...which was sort of right
#795
ChumpCar
Homemade aero is allowed on a point per sq-ft basis.
Wood (up to 0.5" t) = 1pt / sq-ft
Sheet Steel or Aluminum (up to 0.25" t) = 2pts / sq-ft
Sheet Plastic or Polycarbonate (up to 0.38" t) = 3pts / sq-ft
Carbon Fiber = 5 pts / sq-ft
Points are few and very precious. Since plastic is 150% the point cost of aluminum I thought I'd try aluminum for the air-dam and rear spoiler. Some sort of splitter will be made out of wood.
So it's not that the rules don't allow plastic, just that they favor aluminum.
Homemade aero is allowed on a point per sq-ft basis.
Wood (up to 0.5" t) = 1pt / sq-ft
Sheet Steel or Aluminum (up to 0.25" t) = 2pts / sq-ft
Sheet Plastic or Polycarbonate (up to 0.38" t) = 3pts / sq-ft
Carbon Fiber = 5 pts / sq-ft
Points are few and very precious. Since plastic is 150% the point cost of aluminum I thought I'd try aluminum for the air-dam and rear spoiler. Some sort of splitter will be made out of wood.
So it's not that the rules don't allow plastic, just that they favor aluminum.
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#798
http://www.miataturbo.net/race-prep-...11/#post929111
#799
That was me. Epic fail can be seen at the top of page 11.
http://www.miataturbo.net/race-prep-...11/#post929111
http://www.miataturbo.net/race-prep-...11/#post929111
It seems I'll make the first attemp with nature's composite!