Once upon a time, while I was riding on my little Suzuki Best cub-class motorcycle, I reflected that a mere five horsepower isn’t a bad thing if it lets me ride at 70 km/h. And the bike was pretty old, dating from 1991 which I had got second hand, so very likely the motor was putting out rather less than the rated 5 hp.
What is horse-power? It’s the amount of power equivalent to a working horse. And I had 3-5 horses under me, good enough to give Ben-Hur’s chariot a good run at the Circus Maximus, and basically run at 60-70 km/h. Pneumatic hammers are usually powered by air compressors with motors not much bigger than motorcycle engines.
So I wondered about a low-power power suit.
I’ve read Iron Man comics and seen some of the movies. Clearly when people think “power armour”, they’re thinking power output exceeding a nuclear power plant. Supersonic flight, power blasts that can do major damage,
What about a power suit limited to just 5-10 horse power. Think about it another way: give a man the power of five horses. For comical effect, it could even be an outboard air-cooled motorcycle engine. Instead of power servomotors and hydraulics, the suit would be electronic polymer muscle fibre-based, with an outer layer of thixotropic material that’s flexible but stiffens on impact for protection. Good enough to stop small arms fire but it’ still bruise him. Lightweight but strong exoskeletal support. Powered by a fuel cell, perhaps, though the outboard motor would be funny. Lightweight enough to function with power turned off to skimp on fuel.
Super strength? Sure, five horses is plenty strong by ordinary standards. Just not Hulk or Superman strong. “Five HP Man” can smash through a wall (after a few tries), shove a car, carry several people to safety.
Super speed? with the right accessories, perhaps. I don’t see Five HP Man running as such. Maybe roller blading, or pedaling a specially built bicycle with high gear ratio, or maybe Pistorius-style running blades extending from the legs. 70 km/h isn’t fast by inflated superhero standards, but pretty quick and nifty for a man. Actually I suspect he’d much rather drive and only use the semi-super speed inside a mission.
5 horsepower isn’t bad on the water either, though he’ll never outrace a powerboat.
Flight? Sadly no. I did a bit of reading. Ultralight craft need at least 15 hp, with 25-40 hp being the usual. They’re operating dangerously close to stall as it is. Five HP Man might do a powered glide from a height by extending large fragile wings and use power rotors to help extend the flight and then slow down for landing. Aerobatics are out of the question: just turning in midflight might rob too much speed and cause him to stall out and crash. Flight is something Five HP Man would do very reluctantly.
Unless… Five HP Man goes blimping, furiously pedalling a rotor under a balloon.
So Five HP Man would have good endurance (1 liter of fuel is good for many days, if he doesn’t use power continuously), good strength (though underpowered compared to Iron Man), speed albeit not Flash or Quicksilver fast. A hero who needs to think where and when to apply his power for best effect. An enhanced ninja.