Helicopter electric tail rotors

Oskar

Member
Joined
Mar 10, 2007
Messages
251
Location
Auckland, New Zealand
Aircraft
R22, MTO Sport, GyroBee, Mosquito Air
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.
 

Oskar

Member
Joined
Mar 10, 2007
Messages
251
Location
Auckland, New Zealand
Aircraft
R22, MTO Sport, GyroBee, Mosquito Air
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.
 

Martin W.

Active Member
Joined
May 10, 2020
Messages
214
Location
Winnipeg
You continue to amaze me and impress me with your experiments Oskar .... thanks for sharing.
 
Last edited:

Martin W.

Active Member
Joined
May 10, 2020
Messages
214
Location
Winnipeg
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.
 

Martin W.

Active Member
Joined
May 10, 2020
Messages
214
Location
Winnipeg
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.

 

Smack

Re-member?
Joined
Nov 3, 2013
Messages
694
Location
Georgetown
Aircraft
Kitfox IV / F1 Rocket / Magni M-16 / Beech 18
Total Flight Time
500+
Wow, Martin, thanks for linking that fascinating article !

SUPER progress, Oskar ! Thanks for that video. More, please.
Brian
 
Last edited:

grevis

Newbie
Joined
Oct 14, 2019
Messages
20
Location
Hamilton, New Zealand
Aircraft
Mosquito XE285
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.
 

Martin W.

Active Member
Joined
May 10, 2020
Messages
214
Location
Winnipeg
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.

.
 

Oskar

Member
Joined
Mar 10, 2007
Messages
251
Location
Auckland, New Zealand
Aircraft
R22, MTO Sport, GyroBee, Mosquito Air
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.
 

Oskar

Member
Joined
Mar 10, 2007
Messages
251
Location
Auckland, New Zealand
Aircraft
R22, MTO Sport, GyroBee, Mosquito Air
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).
 

NJpilot

Gold Supporter
Joined
Aug 19, 2012
Messages
147
Location
Voorhees
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?
 

Oskar

Member
Joined
Mar 10, 2007
Messages
251
Location
Auckland, New Zealand
Aircraft
R22, MTO Sport, GyroBee, Mosquito Air
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.
 

Smack

Re-member?
Joined
Nov 3, 2013
Messages
694
Location
Georgetown
Aircraft
Kitfox IV / F1 Rocket / Magni M-16 / Beech 18
Total Flight Time
500+
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 !
 

Oskar

Member
Joined
Mar 10, 2007
Messages
251
Location
Auckland, New Zealand
Aircraft
R22, MTO Sport, GyroBee, Mosquito Air
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.
 

Gyrolion

Newbie
Joined
Aug 30, 2014
Messages
13
Location
QLD Australia
Aircraft
Magni M22 M16 M24 R44 R22 C177 C172
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.
 
Top