Helicopter electric tail rotors

Wouldn't multiple electric props survive prop strikes better and with less power per blade be far less dangerous if someone walks into it? Plus the blades only extend a few inches past the supports requiring one to get extremely close in order to get hit by one.
You're right, it would probably survive a prop strike without too much damage. There's a lot less energy compared to a single tail rotor, but it's still very far from safe. Effectively there's a drone that can lift 15kg sitting back there, and a drone that can lift only 1kg will already do serious damage if you get your fingers in the props.

Best to treat it with the same respect that you would a normal tail rotor.
 
Simulated engine failure and tail rotor failure tests were successful, now moving into forward flight.

Here's a quick stop close to splitting needles, everything feels as it should.


One unexpected result from tests was the big variation in tail rotor power between left and right pedal turns. Moderate left pedal turns require more than 4 times the power of right pedal turns, it's easy to see how pilots in conventional helicopters can get into low rotor rpm trouble as a result of manouvers that require very large tail rotor power.
 
You continue to amaze me and impress me with your experiments Oskar .... thanks for sharing.
 
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Also meant to say I have some TESLA (Motors) info you may find helpful in your future .

And it hearkens back to an idea from Nikola Tesla himself. And so far only Elon Musk has figured out how to implement it. There is a reason his motors are more powerful than any others without requiring a lot more electric energy.

I will dig it out and post it later.
 
Here it is .... its a long technical article so here are a few snips

......... With the breakthrough in reluctance machine design these past few years, we may be witnessing a sea change with regards to the powertrain for the electric vehicle market.

..........Given reports about the performance of the TESLA Model 3, the reported jump in miles per kWh that owners are reporting over prior Tesla models .......

........... it’s a reasonable bet that Tesla has perfected the reluctance machine and in doing so has pulled an engineering rabbit out of its hat.

............. Regardless of the exact motor design, Tesla has clearly hit it out of the park with the Model 3’s powertrain.

 
Wow, Martin, thanks for linking that fascinating article !

SUPER progress, Oskar ! Thanks for that video. More, please.
Brian
 
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Maybe you could set up the pedals with a slight exponential response rather than linear. It might make response more even to left and right input.
 
Also found a video that explains the new Tesla motor idea

My electrical knowlege is fairly shallow but I hope experimenters (like Oskar) will find it useful.

.
 
The Tesla and Prius electric motors seem to be the best motors for EV applications, but are still a bit off the power to weight ratios achievable with outrunner motors like the EMRAX motors. Outrunner motors are perfect to aircraft applications, but not practical for EV use.
 
Here is a log of the tail rotor battery current during one of the test flights. The battery voltage is around 23V which means 43A corresponds to 1kW.

Tail rotor current flight 2 230121.jpg
There were some aggressive manoeuvres, and the battery current ranged from zero during two quick stops (the needles were split meaning zero main rotor torque and zero tail rotor thrust) to 140A (stopping a right hand pirouette and pulling aggressively into forward flight).
 
And how are the main batteries and controller handling things temperature wise, much margin there?
 
And here's the flight that generated the log.
Stayed in the danger zone only long enough to take measurements, then back down again.
Wow... wind noise is far louder than a hovering chopper just yards away! With an electric main rotor is managing throttle easier with the instant electric throttle response and torque?
 
Wow... wind noise is far louder than a hovering chopper just yards away! With an electric main rotor is managing throttle easier with the instant electric throttle response and torque?
When starting up the drive is in torque control mode using the throttle to control motor torque. Once speed gets to 60% it switches to speed control mode, all the pilot has to do is keep the throttle at 100% and the drive keeps the speed at 100%. It works amazingly well.
 
My opinion is that you've outperformed Sikorsky and their electric Firefly, Oskar.
Makes your accomplishment all the more inspiring. Keep up the good work !
 
My opinion is that you've outperformed Sikorsky and their electric Firefly, Oskar.
Makes your accomplishment all the more inspiring. Keep up the good work !
Thanks Brian,
I'm lucky that there's a lot of cool gear out there now which wasn't available when the Firefly was built. I'm busy putting on a CAN bus recorder which will be able to log just about every parameter on board, from main rotor rpm down to every battery cell voltage.
 
Oskar, fantastic achievement! It is people like you who are pioneers that lift the bar higher, keep developing your innovations...

Looking forward to further updates.
 
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