Most things have already been tried as already mentioned in this thread. What would surprise me is if an electric tail rotor would be competitive when it comes to reliability and efficiency as long as the power plant is a combustion engine.

Here is a paper on the model shown in the youtube clip, although I didn't see much of interest in there: http://www.cleansky.eu/sites/default...3_-_eletad.pdf

It's obvious that an electrical TR could be made, it would probably be much cheaper to produce than the current mechanical solutions as well. What I seriously question is whether it would be "competitive" with regards to the criteria that matter, especially when it comes to safety. How would you do a autorotation with an electrical tail rotor?

Nadar
You do know you can autorotate with or without a working tail rotor right?

Nadar, there are efficiencies to be gained by the ability to vary tail rotor speed. It allows a designer to move the compromise points. Plus as I stated before the ability to tailor the noise footprint.

As to autorotation, how much torque is the tail rotor dealing?

That depends on if you want to turn (left or right) and keep the aircraft in balance.

Irrespective of how the turning rotor is actually powered, it still needs a blade pitch control system. Varying the speed of rotation isn't the full answer.

Accepted, but say as a ROM % of that in powered hover?

I also wonder why the assumption that an electric tail rotor wouldn't work in autorotation?

Fully agree with that! But having control of both is not a bad thing.

a) I'm not familiar with the term ROM%

b) Did anyone assume it wouldn't work in autorotation? I certainly didn't. However, the tail rotor would still absorb a lot of energy even in autorotation so presumably its electrical power generator would need to be driven by the main rotor transmission, or a very large capacity battery would be required if engine driven generators no longer provided electrical power.

Presumably you could get away from powering an electric tail rotor all the way down in autorotation until just before the flare when it's time to spool it back up again to assist a little later with the run on...

Surely you cannot be serious?

ShyTorque, my apologies, ROM is Rough Order of Magnitude. I ask because this determines the power demand at a critical phase.
Nadar seems to have implied that auto with an ETR would be different to "conventional". I'm not sure why this would be the case, in auto I would presume a design where the MGB is still driving the generators. Question for my own interest, how many helicopters out there revert to battery when in autorotation and how many retain electrical generation?

note: during "conventional" autorotation, the tail rotor is powered by the MGB.

That's what you would do with the gear isn't it? OK just kidding..

OMG there are dozens of chop jocks now, invading this thread!
What happened to the original thread FFS?
Electric TR's. Where do these people come from? :sad:

I had a small RC helicopter with an electric tail rotor once. Worked fine until it sparked a few times and stop dead.
I dont think this helps any. Just thought I would share
playing it safe since the mods deleted my last post

How much did you pay for it? What kind of certification did you get with it?

Sadly TC, as so often is the case, this forum has been invaded by many armchair flyers who have no idea about actual operational Air operations . Best leave to their playtime air ops games!

TF

Or those who have no idea how these magnificent flying machines are designed or certified.

Just to make it clear, my comment about autorotation was with the assumption that the generator would then be dead, and putting enough heavy and possibly explosive batteries in a helicopter to have that as a backup doesn't seem remotely realistic to me. I didn't think of that the gearbox could drive the generator, which I realize now would be the only sensible thing to do.

The autorotation comment was just meant as an example of new problems that would arise with such a "hybrid" system. I still think the main points are that I can't imagine that such a system as a total would be as reliable as a driveshaft and a gearbox, and that it would be much less efficient. I could be wrong, but I still have a hard time seriously thinking of electrifying the TR to reduce the risk of failure.

Very true except the levels of controllability will be different - there is a certain amount of drag within the drivetrain and auxiliary systems (HYD pumps, cooling fans, sometimes generators or alternators etc ) that are driven that will induce the cab to catch up with the main rotor. Also noticeable when you flare to prior to touchdown. Without a TR it will be a bit messy.

Suppose you have to hover next to a cliff or hangar with some serious crosswind. Consider the following:
Is a fixed pitch variable speed electric motor dynamic enough to hold the tail steady? What about tail rotor rpm wind down when the gusts abate, do you need tail rotor brakes?
Perhaps variable pitch constant speed is the better electric option of the two. Now how do you manage power available on two different systems. Will the electric motor run out of puff while the coal burners are just warming up? Are bigger electric motors needed along with all the penalties that introduces?

Some of us like to roll the helicopter in tiny amounts just using the pedals, will the electric fan at the back take this away from us?

Now if you are gunna stick an electric fan at the back at least allow it to pivot around 90 degrees to provide forward thrust.