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Pedal Box Modification


L66TEY

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Hoping someone could help me understand what the purpose/use is for "wedge" shaped part of the pedal box?

To me it looks redundant, hence I can't understand why it features two rivnuts and a sealed blanking plate on the face not shown below. 
 

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With thanks

Chris 

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"Is the duct to let air out or in? Just wondered which way around it should go as don't understand how they work!"

It's a "submerged inlet duct". The original intention of the design was to pass air into the duct with the minimum disturbance to the external flow. This was because they were developed for aircraft, and most commonly the ducted air was needed for cooling.

What is happening to the air at any point on the surface of a Seven is up there with:

There be three things which are too wonderful for me, yea, four which I know not:
The way of an eagle in the air; the way of a serpent upon a rock; the way of a ship in the midst of the sea; and the way of a man with a maid.

: - )

Jonathan

From the original 1945 paper:

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Intention is for the NACA duct to take (suck) air out of the footwell.

In this orientation (pointy part backwards) it will (should) work the opposite to when the pointy part is forwards (like the air intake on the 485 model).

There are lots of comments on a separate thread regarding this - fair to say not everyone thinks it will work.....

https://www.caterhamlotus7.club/forum/techtalk/naca-duct-installation-advise

Chris

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This video is the evidence I have that it will work in reverse, hence I feel comfortable (sort of);

Pushing the Envelope - Backward Naca Ducts

Plus, as it happens I have been lucky enough to source a bonnet which I can cut my "maiden" hole in.

 

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For it to work, the air pressure on the outside will need to be lower than on the inside. With the profile of the bonnet widening by the duct and the blockage of the windscreen in the flow, there may be an increase in pressure on the outside of the bonnet in the duct area, unless the vortices from the edge of the windscreen have a scavenge effect in reducing the pressure in the area near the duct, as well as the area behind the windscreen.

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  • 2 weeks later...
  • 3 weeks later...

Having created a hole, the irony is I now need to fill it. 
For this I've turned to CAD (both the Cardboard and Computer Aided Design variety). 
Here's the work in progress laptop CAD

;

E6EA50CE-6F60-475F-9E16-BFE02314CC29.jpeg.54253e95b605e3aad34b853f842be74e.jpeg

B72D6AA3-8278-49A4-B254-9A61A410D712.jpeg.f2d659cdea39ecfc99290dc4f3a8c0c9.jpeg
2B245192-E3A6-49A7-960B-7683A432DB31.jpeg.6b59667db41ea850fcbc938ebd16e951.jpeg F991AE34-AB06-40BF-9963-532D8986EA24.jpeg.57a3e49be64c366892cabc836cfb45b2.jpegI've scrapped the idea of using 3D printed plastic, due to the firewall requirement, instead opting for 2mm sheet. 

Chris 

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