Eric has been making great strides with the body. Eric has requested that I don't post any pictures of the progress until we are all done.
That way he can post the progression from start to finish within a couple of post.
We plan on fitting the body to the chassis in October.
It has been interesting moving from cad to parts on the body. The flap molding into what were essentially "boxes" went flawlessly and convinced us to go this route on any constant tapered sections. We had planned on a male mold for the wing sections. This didn't work as well as hoped, so we are re-doing it in the manner we did the flaps.
The fuselage has been an interesting challenge. There are seven separate longitudinal control lines, all were gradient optimized with software I wrote, all were combined in cad and generated exquisitely smooth pressure and velocity contours when tested with CFD. Wing down-force vs. flap angle agreed with predictions to 1%. This meant that we could add bumps or blister fairings for anything that didn't fit with confidence and any joints aft of the laminar transition would be non-issues.
The nose section all the way to the firewall will be one-piece, with some very innovative structural attachments that Rob has worked out. We will have multiple points of support every few feet with no external fasteners to trip the laminar flow. And yes, it will be easily removable for tech. Once the nose goes on at the beginning of the week, it will probably stay. All service items are aft of the firewall or accessed through the cockpit hatch. We are debating about doing the engine/transmission area in 2 vs. 4 parts and we need to decide how much intermediate support we need in these areas. This is a 500 psf car (essentially the aero stress level of a military trainer), and needs about 4X the attachment and skin stiffness of a top fueler. One-piece hinged body shells will shatter at these speeds.
The challenge has proven to be the translation of the upper to side and lower to side control lines vs. the gradient optimization. Each control line has certain features that line up differently vs. their station. We solved the pressure recovery (aft) areas first and everything averaged out vs. the water jet forms within 20 to 40 thousandths. The real challenge has been on the front end where we are seeing 50 to 90 thousandths variations to achieve a smooth contour.
I can tell everyone this: Rob's plan of CAD-to-water-jet-to-foam-to-form, these are the cheapest and best molds I have ever produced. Nothing shy of expensive high density form board and a gantry CNC mill could translate design intent to reality as well as this; and that would have been 3 to 5X the cost.
The only problem is that by designing a perfectly gradient optimized shape, we have bought into a continuously changing curveture at every point of every surface. Even the slightest bulge or dip shows and there are no flat surfaces to just run a long board back and forth on. It would have been so much easier to build a pointy-nosed-brick; I wanted the low drag. We have actually invented our own 3 and 5' conformal tools to achieve the required contour to +/-.010". The linear parts like the wings, flaps, and wheel fairings are flat across their span so they are simple and quick to form even though they have continuous curveture in the chord axis. The fuselage is a work of art, albeit an expedient one, and we will be publishing pics of it soon.
Congratulations to Rob and the 3838 Corvette team on their record and red hat on their first time out. I had the priviledge to spend a week with the Carbinite team in June and they are true professionals. I had to stay home from speed week this year due to family health issues. I look forward to going to Mike Cook's shootout after the air races.
