I think it is quite logical that the layup data is not shared. It is after all a strange situation that nearly all commercial build velomobiles are build in the same factory, by the same people. Wich one is faster is highly debated, and argumented about. Not all arguments are reliable and sometimes get deformed. exposing such details might lead to whole lot more half informed arguments. Daniel Fenn educated lots of those ladies in laminating techniques. He has a very intuitive understanding how carbon and fiberorientation works. With his velomobiles it is often more difficult to see the reinforcements as they are in the laminate and in shape. With velomobiles like the Milan MK7 and the Bülk u can see clearly several reïnforcements. Looking at the Milans, u can see the evolution from the M2 to the MK 7 and then the next step with the Bülk.
The use of Innegra and another material (nylon?) as a saftey layer, between the carbon, is another important step in making velomobiles safer. They have different properties and help to keep things together after impact.
I can say that huge parts of the surfaces of velomobiles are very thin laminates. On the old Fibreglass Quests, the nose would dent in if you would put a heavy teamug on it. Even on modern velomobiles there are many surfaces u can move in with mild finger presure. Other parts are solid Carbon, like the ear on wich the rear suspension mounts in the Alpha's.
A velomobile is a unibody. On a unibody car many of the bodypanels are very thin and not realy structural. Underneath there is a structure of often hollow shapes, chambers, channels that provide the real strenght. It is comprehensible how forces flow from one part to another. The WAW has a similar structure with ribs. Early Milans did not have that, later ones did. The Evo K was one of Daniels first ones, and it has in the rear a very clear hoop. But his designs evolved and now he can do without a visible hoop there.
The wheelwells and the bridge between them are structural, the chaintunnel is, the nose mount of the beam is a structural part, including the shell area that accepts it, the front side of the rear wheelwell is also a structural part. As is the edge of the entryhole, the hump behing the head, that also acts as a rollbar. The lower side corners are also very important.
On my plywood velomobile the entire shell is made from 1,5mm birchply. There are two 5mm thick and 40mm wide strips of cheap fir lenghtwise to connect the curved corner sections. The upper and lower corners. The entry hole has sides of 20x20mm square beechwood. That is mounted diamond position, and the inner corner is rounded off significantly. On the floor in the corners there is a single layer of very thick Carbon cloth. 370, 400gram there about. That is enough. There is movement in the shell under torsion cause i failed to connect the entry hole good enough to other parts. I made a later add on's to connect the rear part to the rear wheelwell. That is made of high quality (Bruynzeel) 3mm Okoume Also strong enough. I lack a good connection between the front of the cockpit hatch to the front wells.
This also provides a bit of reading material.
https://cmoder.gitlab.io/velomobil-grundwissen/velomobile_knowledge.html
There was some aerodynamic testing done at a university in the north of Germany. The results do not match with real life facts about the performance of the different models. Even the people that done the testing made disclaimers about the results being inconsitent with the actual situation. I do not think it is the result of poor testing. But most aerodynamic tests simplify the situation, leave out disturbing factors, to get clean results. In reality, with a moving road, inconsistent wind direction, etc the airflow is probably less clear and predictable. Yet that same windtunnel was used in improving the design for the Bülk.
Even with a very high skillset and theoretical knowledge, one can't design and build a fast aerodynamic recumbent without practical experience. The most monumental cockup was team Blue Younder with on paper a perfect Battle Mountain streamliner.
http://www.recumbents.com/wisil/whpsc2001/Blue_Yonder_Team.htm
It was simply way to big and even with a very powerfull rider it was outperformed by a 14 year old kid in a realy fast streamliner. There is a more detailed story on that somewhere on the web, but i can't find it quickly. Theoreticaly their skill and performance data was briliant, they failed on lacking practical knowledge and experience, they where not even smart enough to properly check out the competition. Had they done that they would have noticed how much bigger their streamliner was. One can't learn to be a carpenter, just from books. You have to pick up the tools. It is the same here. A computer model won't tell u how much space a rider needs to be able to pedal within a shell. U need to find that out by trying. Among other things. Don't fall in to that pit.
If u want to go realy fast, forget about open wheelwells would be my advise.
Designing and building your own Velomobile is a nice proces, and i have learned a lot from it.
@benparke has similar experiences he has made some very good video's about that also. Check out his channel
https://www.youtube.com/channel/UC0LEPEHTrUFBAMWYkgnkFDQ/about
One of the things i knew from the start is that i would never get to the level of a good commercial one. Both Ben and I finaly bought a commercial model, and i think we would both say that the commercial one is an overall better product. Building in wood saved both of us from the potentialy very large investments in building a plug, a mold and only then the final Velomobile, as is needed when going with composits alone. The ammounts of material needed for plug and mold are
probably higher than the price of just buying one.