Formula One In School - Adroit Project

[Izzy410]

true but the back would be 8 grammes heavier with a cartridge

and right now even the weight distribution is about 30 - 70 without a cartridge.

[flynfrog]

Im not sure how you are getting your wheels but if you can make them with a disk instead of spokes it would drop some drag. Spokes make your wheel act like a pump. The trick is to get the mass down at the same time. You also still have pretty sharp leading edges on parts of that car. The side pods and the spikes in front of the car come to mind.


JT- I don't consider this to be blind engineering at least not completely blind. Its like using a pair of calipers. When you first use a set you might not fully understand how they work and how to read them but you can still tell if a bolt is longer than another most of the time. To me blind engineering would be making these changes with no way to test. While the testing is not 100% accurate it is still better than a stab in the dark. Besides how many people do you know in high school that even know what CFD software is let alone have even used it.

[Izzy410]

Thank you,

understood about the tyre but the VWT has only THAT tyre. because the tyre gives important feedback about weight distribution so i cant take it out but i can retest using a no spoke tyres like you said and see how that effect the outcome.

the design we have in mind is a kin to ferrari's static wheel base design on their F1 car. we are in discussion with an overseas supplier. we are thinking of Carbon Fibre but i managed to get a local supplier to create the same design out of delrin (a sort of light weight plastic). the design is quite light although i still have issues on the weight. i could use a wheel that weighs only 3 grams but still being rigid. currently the weight of the wheel is 4.7 grams with carbon fibre. any suggestion on lighter materials?

When you say sharp flynfrog, what do you mean by that? Right angles or 'sharp looking' shape? i could understand about the front spike (front pod we call it) but what of the sidepod?

[tok-tokkie]

Delrin is nylon (Du Pont trade name). Acetal is harder which may give less rolling resistance but the loads are so low that that is hardly an issue. Acetal is the easiest plastic to CNC machine in my experience. Could make the wheel extremely thin.

[flynfrog]

[Izzy410]

So you suggest acetal.

to give perspective the wheels would carry a maximum load of 65 grammes. but the distribution varies.

the front carries 22 % of the weight while the rear carries 78%. this doesnt include aero pressure like downforce or lift but i do have a data that suggest a aero pressure

Front = -6.425109E-03 N ( 6.549550E-01 gm)
Back = -8.270504E-02 N ( 8.430687E+00 gm)

I might need a few advice in interpreting this.

and the size of the wheel is 26.5 mm in radius and 16 mm wide. if the tyre flex with a thin wall the increase surface area touching the track can increase drag.

I might have missed this information but we are not trying to win the race but trying to break the current 1.020 second world record. which i think if it broke the record you could win at the same time. so we are engineering the car as best as possible.


EDIT: i found this on wiki, it says acetal and delrin is the same thing?

Polyoxymethylene (commonly referred to as POM and also known as acetal, polyacetal or polyformaldehyde) is an engineering thermoplastic used in precision parts that require high stiffness, low friction and excellent dimensional stability. It is commonly known under DuPont's trade name Delrin.

[Izzy410]

Okay. got that part for the front spike/pod. but what about changing that side pod? the air is channeled above and below and around it and not touching the pod (due to the tyre) itself so we are taking shapes that fill the vacuum as best as possible instead of streamlining it or am i going the very wrong way with this concept?

[pudin]

I think about the tyres,most of the team in national use the static wheel base,even my team use it.
It only weights about 3.2 grams each.

[flynfrog]

Okay. got that part for the front spike/pod. but what about changing that side pod? the air is channeled above and below and around it and not touching the pod (due to the tyre) itself so we are taking shapes that fill the vacuum as best as possible instead of streamlining it or am i going the very wrong way with this concept?

the concept is good but the rules dont let you get the wheels well covered it might be better to make the side pod an airfoil.

[Izzy410]

okay even if i liked to do that i cant. my sidepod is at its minimum size. at absolute minimum with 2 mm as tolerance. but thanks on that part

I think about the tyres,most of the team in national use the static wheel base,even my team use it.
It only weights about 3.2 grams each.

understood 3.2 grams with or without bearing? if so, one or two bearings? and did you mean the wheel without the cover or with the cover?

Curse i mislooked my design. i calculated weight including rim cover which is static -.- i only need the rotating wheel cylinder to spin and that means only that part needs to be light. i can reinforce and include bearing to make it weigh 3 grammes.


anyone have any idea in making Star CCM monitor drag result?

[pudin]

okay even if i liked to do that i cant. my sidepod is at its minimum size. at absolute minimum with 2 mm as tolerance. but thanks on that part

I think about the tyres,most of the team in national use the static wheel base,even my team use it.
It only weights about 3.2 grams each.

understood 3.2 grams with or without bearing? if so, one or two bearings? and did you mean the wheel without the cover or with the cover?

Curse i mislooked my design. i calculated weight including rim cover which is static -.- i only need the rotating wheel cylinder to spin and that means only that part needs to be light. i can reinforce and include bearing to make it weigh 3 grammes.


anyone have any idea in making Star CCM monitor drag result?

Yes with two bearing applied.
The tyres similar to basizeland tyres which the bearing placed at the center part of the tyre not the outer side.
There are teams that their tyres only weight about 1 gram each,USA maybe,in 2008 world championship.
But,it is custom made and i didn't remember what material used.
I think Acetal or Aluminium.

[Izzy410]

that might be a good thing to research into. i'll try and get some more information. thanks for the lead.

1 gram would be great. aluminum if im not mistaken is used by Zer0.9 last year. and they said the chrome finish on their car weigh only 5 grammes instead of the normal painting made by airbrush that weigh 10 grams.

I was thinking carbon fiber would be stiff enough to be made with super thin wall and not flex under the weight. i researched and they said it is possible. a contact in USA said they can make it at a reasonable price and sort. maybe i'll order a set and test it out.

anyhow boca bearing and VX Bearing quoted the same price for full ceramic bearing. any idea on which i should order from? its an expose bearing but because its in the housing of the wheel it shouldn't be a problem. the flanged design are more expensive.

[tok-tokkie]

Thanks for correcting me about Delrin. For years I have been under the impression that that was Du Pont's name for their nylon. Having just checked up their nylon is called Zytel.

[Izzy410]

Okay sorry i was away for a 4 days convention on a last minute call. so i didnt have time to say my absence. alright.

I will update the design to a new front pod as explained by flyn and call up some supplier for acetal. i need to find something rigid and light. it can be shaped to be absolutely thin for the tyre.

[Izzy410]

No design beat the older design in term of Cd. i made some new ones. trying to incorporate some aero items to reduce drag. like turbulence generator etc.