Way back, about a hundred years ago it seems, when I was making the aluminium panels for the cars, I had some aluminium off cuts so I made a couple of additional rear under floor panels for my car. The hope is that with a full length smooth floor the car will have somewhat less drag.
I always thought that I would fit these on at some stage, but I baulked when I realized that one of them needed a removable section to access the underside of the engine for oil changes etc. Initially I thought that I would remove the whole panel and drill out the pop rivets holding it in place, but the more I thought about that, the more ridiculous that seemed. I had just spent long enough lying on my back with the car suspended 1m in the air fitting the front floor with 100+ pop rivets with the lazy tong pop riveter, and had no desire to do that again with the rear section just to do an oil change. I needed to make a removable section that allowed me access to the critical areas.
It is not immediately obvious in the pictures but the large rear panel is fully pop riveted on, again with countersunk head rivets, so that the heads don’t get knocked off in case of an untimely excursion across a ripple strip, and a section of it is cut out underneath the engine. There is then an additional removable plate that covers the hole, secured with dome head stainless bolts, into nutserts in the chassis.
As long as the shake proof washers do their job well I hope that the securing bolts don’t come loose and fall out! They will have to be on the “continue to check” list.
On the last piece of the under floor paneling I folded each side down into a mini diffuser. This last part of the chassis does come up at an angle, but I doubt that it is going to do anything other than look pretty good!
I guess I’ll just have to wait and see.