For eons, hacker minded people have looked at various items their pile of stuff, came up with an outlandish idea and thought “I wonder if it would work?” Some of us stop there, convincing ourselves that it’s a bad idea that could never work. Others of us such as [Peter Sripol] are well known for not just having those thoughts, but for having the grit to explore them to their impractical limit, such as is shown in the video below the break.

Peter begins by adapting a model airplane propeller to his 9500 RPM battery powered grinder, and then checks thrust with different propellers to see which seemed most efficient. Then [Peter] did what any aerospace engineer out of their right mind would do: He had his brother design the resulting aircraft, which was inspired by an obscure German WWII asymmetric aircraft design.

Did it fly? It did, and you can see a couple of iterations of it tooling around in the video. But what happened next was equally interesting: First, a grinder powered single bladed helicopter and its subsequent hilarious failure, and its slightly more successful successor.

We’ve of course covered many angle grinder hacks, such as this fixture for perfect cuts (something notoriously difficult to do with a handheld grinder), but this is the first time we’ve seen an angle grinder fly out of more than frustration.  Do you have your own angle grinder hack to spin our way? Be sure to let the Tip Line know!

I dont get it. Why did they not have 4 angle grinders set up in conventional drone config and two angle grinders for a conventional twin prop plane?

P38 LIGHTNING style plane. Helicopter would work better if the drive propeller was thrusting up and the helicopter blades were driven by the propeller’s torque reaction. I remember Cox had a gas powered helicopter that worked this way in the 70s.

I would suppose if they did, someone would say, “I don’t get it. Why not just use one motor and offset the wing and tail to compensate?”

I don’t get it, why did they not remove the propeller and make it the first angle glider :o

Drones have counter-rotating props. Not sure about twin props?

Angle grinders always spin the standard way AFAIK. Hacking them to spin the other way would I think be a major rebuild as the whole axle is threaded the correct way.

Just flip 2 of the angle grinders 180°. Then you don’t have to rewire anything. Though if they are just cheap brushed motors, you could just reverse the polarity. I figured he didn’t do a drone because 4 angle grinders would 4x as much.

If you flip them you will still have same rotation. You will increase the longitudinal torque which may still be acceptable but you will have a critical motor.

This guy knows his stuff. He’s the type that if he hears “that’ll never fly” he responds “hold my beer”

(in before the safety squad gets all pedantic)

Red propeller tips are bad luck!

Nah, they are just a precursor to the obvious end result.

Got it from a retired test pilot. Didn’t just make it up on the spot.

I love the superstitions around stuff like that.

if i didn’t have bad luck, i wouldn’t have any luck at all!

I was arsing around with a Black and Decker dremel knockoff that ran off 12V back in the 90s, since it was a compact powerful motor. I had one to use as an actual tool and then I picked one up out of a scratch and dent selloff, no chuck, missing transformer and most of the accessories missing, so after it sat all of 2 months waiting to be spares for my actual tool in use, it got cobbled to an airframe. Batteries were of course not real easy back then, it ate through nicads real fast, and my prop and airframe matching was hit and hope so it only just stayed aloft hauling 10 double A for a few min.

After a little consideration, I guess the format that would appeal to me most for applying that particular tool to a model aircraft, would be a pylon pusher standing up between the wings.Weight right over/near the CG.

I always wonder why we don’t have hybrid drones: use the energy density of gasoline to power one big counter-rotating double life rotor which provides e.g. 90% of lift.

The use 4 standard brushless drone propellers for navigation.

I think because petrol engines are a lot more complexity and maintenance work compared to electric motors?

Because you may as well then put a swashplate on the main rotors and you’ve now got a regular coaxial helicopter

Let’s use the heaviest possible motors with the lowest power to weight ratio for our aircraft……

They were totally going for optimal performance -woooosh-

Take the angle off of the angle grinder

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