What if I strapped a giant EDF jet to my carbon road bike?
I have to admit, when this idea dropped onto my mind, I couldn’t understand why I’d even give such madness any chance of pursuit. At the same time, it felt strangely obvious to do…
Well safe to say, I have a carbon racing bike (that I like), and I also have a bunch of interesting (unused) items, such as a 120mm electric ducted fan that can produce 83N (8,5kg) of thrust, while running on a proper 12S LiPo setup, pulling 120A at 45V. So the obvious idea occurred of “Why not combining that and see what we get?”.
Given a nice flat road, standard atmosphere, and windless conditions, my carbon bike peaks at around 32mph or 51kph under my own power. In theory, the thrust on this 120mm EDF alone could push that top speed far beyond 40mph or 65kph. But I imagine it functioning closer to a “drag cancellation machine”, where it just assists the rider in continuously maintaining a ridiculous speed they would otherwise just call their peak. An interesting construct that might almost be adjacent to a human/machine interface like an exoskeleton, but also not at all… since both systems are not hard-coupled in a physical way.
Electric ducted fans (and all other jet variants for that matter) have a very interesting propulsive efficiency curve based on speed. So this is probably really put into best use as a hybrid human assist mechanism, which jumps in past a certain speed. Pedalling would therefore provide the efficient baseline propulsion, while the comparatively inefficient EDF would act like an afterburner on a high performance jet-aircraft, engaging only when higher speeds are desired.
Given these parameters, it’s tempting to speculate where the theoretical top speed might actually land when both systems fully engage.
If nothing else, it remains an entertaining thought experiment that’s simultaneously so simple and ridiculous, it’s almost worth building.