Lotus Elan

Cosworth YB Turbo Into Elan

PostPost by: Andy8421 » Thu Aug 02, 2018 3:33 am

Steve,

If the splitter is working as advertised, it can generate some decent loads. Clearly the speeds are much higher, and splitter surface area bigger with modern circuit cars, but there are many examples of cars with cable stays from the bodywork out to the front edge of the splitter to help reduce the cantilever effect trying to snap the splitter off.

I can't tell what reinforcing is in place from the pictures, but have you figured out the forces and have adequate strength in the splitter area?

Great work by the way.
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PostPost by: stevebroad » Thu Aug 02, 2018 9:02 am

Andy8421 wrote:Steve,

If the splitter is working as advertised, it can generate some decent loads. Clearly the speeds are much higher, and splitter surface area bigger with modern circuit cars, but there are many examples of cars with cable stays from the bodywork out to the front edge of the splitter to help reduce the cantilever effect trying to snap the splitter off.

I can't tell what reinforcing is in place from the pictures, but have you figured out the forces and have adequate strength in the splitter area?

Great work by the way.


Thanks.

The splitter is an integral part of the front clip. 4 layers of carbon, 5mm foam core then another 2 layers of carbon. These layers extend up to the bottom of the grill opening. I decided to build the splitter into the clip for various reasons, the main two being:

Ease of attachment, no stays or fixing bolts required. Stays and bolts add weight and require mounting points
to be rigid, adding more weight.

Greatly stiffens the front of the car, thereby reducing the amount of carbon required elsewhere and saving
weight.

The length was chosen after a lot of research. 100mm was settled on because:

Front downforce starts to tail off after around 100mm.

splitter-length.jpg
splitter-length.jpg (16.56 KiB) Viewed 388 times


Adding too much front downforce would require additional rear downforce to compensate, resulting in more
drag and I am looking for as little drag as possible.

Anything longer started to look out of proportion to the rest of the car. Although performance is the
predominate criterion, aesthetics are still important :-)

The only downside, and why most splitters are detachable, is if I hit something with it a lot more damage will occur, which is one of the reasons circuit cars have detachable splitters. However, If I hit something with it on the drag strip a detachable one would make little difference :-)

It may not look like it to some, but a fair bit of thought, research and design has gone into this car. I haven't simply followed convention or the sheep :-) Also, as there is nothing on the shelf that I can buy everything has to be designed and built with no reference to similar builds. I live or die by my decisions and build quality :-)
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PostPost by: stevebroad » Mon Aug 06, 2018 9:05 pm

Just made the gurneyish strip that will deflect the air around the join between splitter and undertray. No I just have to cut the undertray to match. This could be a tad tricky as I willbe working upside down and the tray will cover the strip so I will be working blind. Trim a little bit at a time, methinks, until I can see the strip's front edge.

undertray-gurney-glued-060818.jpg and
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PostPost by: stevebroad » Wed Aug 08, 2018 1:04 pm

Front section of undertray now fits.

undertray-front-section-cut-to-size-080818-1.jpg and


Next task is to make support brackets for the undertray. Settled on a carbon/aramid mix as it is more flexible than pure carbon, allowing the brackets to be sprung on to the front clip support tubes. It is also better than aluminium, being less than half the weight (7gm compared to 17gms) and grips the tube tighter.

https://youtu.be/r0HrE3rZWME
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PostPost by: stevebroad » Fri Aug 10, 2018 9:54 am

Made a few more aero parts today so I thought I would gather up everything not already fitted. This lot weighs a humongous 5kg :-)

aero-parts-090818.jpg and
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PostPost by: stevebroad » Sat Aug 11, 2018 5:32 pm

Sorted out water leak trap, thereby using undertray for two purposes. Also the trap sides add additional stiffness to the tray, negating the need for additional strengthening. A win win :-) I will do the same on the tray under the engine.

undertray-water-trap-110818.jpg and
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PostPost by: stevebroad » Mon Aug 13, 2018 9:25 pm

In correspondence with my tame aerodynamicist with regard to the layout of strakes, skirts, splitters and VGs on my new underbody panels. Also discussing diffuser design.

underfloor-aero-design.jpg and
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