What if...
1...someone with more money than good sense bought four of those high tech brushless motor, high voltage LiON electric mowers, gutted the motor and ESC from each one, fitted the motor up to a sturdy airframe, then added a NAZA or Pixhawk FC, GPS and radio.
For example, the Kobalt/Greenworks Max mowers have an 80v LiON system and brushless motor, pushing a 22" heavy steel mower blade through grass and weeds. Surely that system would have sufficient power to push a 16 or 18 inch rotor (20"? 26" even?) Four of those working together would give you a drone with a potentially mind-boggling payload capacity.
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I'm sure it could be a bigger prop than that... 22" through grass is way tougher than air.
I have a greenworks 80v blower and the speed controller is weird. You pull the trigger and it takes a second before it does anything. Not sure why that is. But big enough speed controllers might be the challenge with this.
It would be really easy to run afoul of the government's weight regulations with this system. 55lbs doesn't seem out of reach.
@djslack I haven't been able to find any weight info RE: The 80v battery. Can you approximate the weight for me?
The reviews I read on the mower suggest 30-35 minute operation time. So I would anticipate needing at least two of the batteries in the system to provide any meaningful flight time.
Perhaps the better option is to seek out a battery that isn't part of a system, pick some big fat motors and rotors and piece a system together rather than trying to scavenge the bits. The thing that attracted me was the somewhat reasonable price of batteries. A 22v 5500mAh battery for my Tali H500 is $130. Those 80v batteries can be had for significantly less than that.
I just did a quick check on the motors. Shipping weight is 12.4 pounds. With the weight of the battery, it's almost certainly over 55lbs.
Back to the Darwin Awards drawing board...
@ruouttaurmind weight of just the battery on Amazon is around 6lbs. The cost I saw on there for that battery was almost half the cost of the mower
and well over $130.
@DJMajickMan I found several in the sub-$100 range, and a couple "factory refurb" for $80.
The motors are somewhat reasonable, priced around $50 each.
In retrospect, it seem more economical and efficient to just start from scratch with hobby-grade parts. The Tarot 6115-320kg specs at 5kg thrust at 24v, 3300rpm. In a hex configuration, that's a potential of about 65lbs curb weight. Well above the FAA's 55lb limit. Surely it will be possible to find a high power 24v LiON battery with sufficient capacity to provide a reasonable flight time.
EDIT: I neglected to reduce the total potential to accommodate takeoff thrust. So total potential is probably closer to 45lbs, or 65 in an octo configuration.
@ruouttaurmind
I have the "standard run" battery which is I think 4000mAh, where the mower probably prefers the extended battery which is double the capacity. Size is about 6x4x3 inches. I am willing to bet it's filled with cylindrical cells like 18650s, which means they're tough as nails but not good for super high discharge rates. Let's say the mower has an 8ah battery and runs for 30 minutes, that's a 16a draw or 1280 watts. The voltage gives you a power boost with lower amp draw, while 22v hobby lithium packs can supply 4400w (an 8000mah pack at 25C) if my math is correct.
Weight is 51.8oz or a couple of ticks over 3lb. You could definitely do better with hobby parts, but if you ran across four or more of these mowers you could certainly scrounge yourself up a multicopter that would probably fly well. Wonder if the motor is a big outrunner or geared down to swing the blade?
Look up giant scale electric planes for some power setups that would be up your alley. There are brushless replacements for largish (50cc? More?) gas engines for third scale rc planes that will hang on the prop for an indefinite time.
Or think bigger. Could we take apart a Prius and build a quad that would lift a family of goats?
@djslack @ruouttaurmind Forget the Prius. Go with the Tesla Model S P90D with Ludicrous mode.
and build it as a collective pitch quad.