At the beginning of each aircraft project there is the constraint diagram. Designing an ultralight jet is one of the most challenging things to do, both due to the limited CG range and due to limited thrust from small turbojets.

I will disclose the constraint analysis that our lead aerodynamic specialist created before we started the Beast project. The math behind it is filling multiple pages, but I will show the outcome, so you get the point:

The constraint diagram shows a combination between thrust to weight (for jets, for piston it looks a bit different) and wing loading. It basically tells you where your journey will go in terms of wing area, aspect ratio, etc...

You create constraints like your weight, your target wing area, take-off run, climbrate, stall speed, etc. and it will result in a curve for each constraint. Your plane will be feasible, if your T/W is above all lines. For propeller planes, it will look like U-shaped lines, but for the jet, they are looking rather like decaying exponential functions.

As the jet is in the 1000N range the T/W will be only ~0.25, so the remaining area is rather small as you can see. The diagram will tell you, that the optimum plane (orange dot) will have a wing load between 200-250kg/m² resulting in a wingspan of 4.1m and 1.7m² wingarea. For this to work, the required Cl results to be in the area between 3.6 and 4.1. I will not comment on this, but you see, using state of the art calculations, it is impossible to build a plane like this. This is the reason, why our competition behaves sooo bad at low speeds and is exactly where we want to improve (not on top-speed like most guys).

The JSX-2 has in reality a span of 5.5m with 5.6m² of area and a Cl of ~1.3. You see, that following state of the art designing technique, the T/W ratio should even be in the area of 0.5 to fulfill all constraints!!!

It was hard convincing my aerodynamic guy to trust me such a plane could fly decently (even after showing him BD-5 and JSX-2) in reality. Do you understand now my scepticism how the JSX will perform with 2 people on board?