Pedal Box Modification

[L66TEY]

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. 
 

With thanks

Chris 

[Wrightpayne]

Fly by wire throttle?

[L66TEY]

Didn't think fly by wire was used on RHD (non EU5 reg)?

Or are there specific models eg 620 that features fly by wire??

Either way I plan on removing part of this "excess" metal to make room for footwell venting via NACA duct fitment. 

[simon_h]

That is where the electric throttle pedal bolts to. Used anywhere the eu spec went to rhd markets, Australia, Japan etc and with the 160/170 everywhere 

[L66TEY]

Thank you Simon,

Thats given me the peace of mind I was looking for to modify the pedal box as applicable, for NACA duct clearance. 

Wish me luck with this mod over the Xmas period 

Chris

[Wrightpayne]

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

[Jonathan Kay]

"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:

/Users/jonathan/Desktop/Screenshot%202021-12-14%20at%2012.05.29.png/Users/jonathan/Desktop/Screenshot%202021-12-14%20at%2012.05.29.png

[L66TEY]

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

[TomB]

fair to say not everyone thinks it will work.....

It'll look cool though  

[OldAndrewE]

There must be some way of testing if this will work (i.e. that it will work as an extract duct) without taking the irreversible step of cutting the bonnet.

[Wrightpayne]

Could always look for a damaged but useable bonnet to test it? 

[L66TEY]

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.

 

[simon_h]

Well that video seems to suggest they might well do something  Giving it a go cant hurt can it? 

[aerobod - near CYYC]

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.

[L66TEY]

Reply to #9 and #13
Thank you Tom and Simon.
Whilst Im wanting to let "function" rule over "form" - admittedly the "vanity" element makes for a nice bonus 

[L66TEY]

Reply to #14
Thank you James - you clearly know a lot more about aerodynamics than I do.
Perhaps its wishful thinking - but either way I'd like to think that my objective of getting air flow to the pedal area will be achieved
Chris

[L66TEY]

Pedal box modifications have commenced.....

Chris 

[L66TEY]

And the cutting continued to this point

[L66TEY]

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

;

I've scrapped the idea of using 3D printed plastic, due to the firewall requirement, instead opting for 2mm sheet. 

Chris