> The BD-5 is a propeller-driven plane with an internal combustion engine, which Bede derived from a sailplane version he never sold
The BD-5 design was copied, deliberately and publicly, from a Schweizer glider. The goal was, always, to produce a powered light aircraft. The B model, the glider, was an offshoot of the A model. As it turned out, the A model wings were substantially under-designed, and an intermediate length was substituted on most models. All of the designs initially made considerable use of fibreglass, but the entire series was moved to aluminum as the orders poured it.
The design was flawed from conception to construction. It fails due to a well-known issue in aircraft design, as it is "close coupled". The short length of the aircraft means that there is limited distance between the various force points like the CoG and CoF and the control surfaces. Exasperating this is the rear mounted engine, which means there's only, literally, inches between the heaviest part of the aircraft and the control surfaces. That means the controls have to be made larger so they have enough force to operate at low speeds. However, this also means that they are dramatically overpowered at higher speeds. There's no way around this, its basic physics. The "solution" for more expensive designs is powered controls and artificial feel.
Worse, in terms of the length of the aircraft, moving the pilot's seat a few inches is more of a relative shift than it is in, say, a Cessna. This means the aircraft is extremely sensitive to changes in W&B. Even something as minor as burning off fuel will require constant trimming, and that trim point will, for the reasons outlined above, change with speed.
So all of this conspires to make the aircraft difficult to fly on approach. As the aircraft slows the trim keeps changing. Combine that with high approach speeds and ever-more-sensitive controls. And finally, put the thrust line above the aircraft, so if you goose the engine it pushes the nose down, precisely the opposite of what you want it to do.
There is a reason a Cessna looks like it does. It is, for the vast majority of cases, the proper layout for an aircraft. Canard and other layouts have well known advantages in particular situations, but these are generally offset by their disadvantages which is why they are used only in edge cases like fighters.
The BD-10 was a joke from start to finish. Bede had no idea what he was doing, which is not surprising because he never really did any of the design on any of "his" projects - the actual design was left to young engineers typically fresh out of university. In the case of the -10, it was designed using a piece of Mac software known as MacFlow which had a number of bugs in both the software and the models. They initially predicted supersonic performance, but this was due to a bug in the model, From that point on the performance of the aircraft continued to degrade as drag and weight increased continually.
Building a transonic aircraft from pop-rivets? Yeah, that will work...