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The future of the helicopter is electric.

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The future of the helicopter is electric.

Old 7th Sep 2010, 14:32
  #61 (permalink)  
 
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A breaktrough where one could develop a generator or alternator capable of recharging the bats while you are airborne.

that would be the mystery solver
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Old 7th Sep 2010, 14:34
  #62 (permalink)  
 
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and we only have 50 more years left of oil in the world... so we need to come up w/ something fast!
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Old 8th Sep 2010, 07:20
  #63 (permalink)  
 
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1) How is a high power generator, remote electric motor (heavy!), power regulation system (probably including huge buffer capacitors to deal with sudden load changes) less complex OR lighter than a driveshaft and a 90deg gearbox?
Unless you've been an R/C flyer in the last 10 years and seen the revolution there, I don't think everyone here understands just how light and efficient modern brushless motors are.

I can buy and off the shelf 20hp brushless motor that weighs 2,5kg (5lbs)!

Hacker A200-6 Motor - HAA2006

With even more exotic materials in the housing, that could probably be made even lighter. No drive shaft, tail rotor assembly or linkage is ever going to be lighter than that.

Just as a thought experiment: an R22 probably needs, what, 10-15% of the power to power the tail rotor in its most extreme condition? That's roughly just about 20hp. So this itty bitty brushless would be able to that job. Cost less, vibrate less, weigh less and be more reliable.

And since they are so light, you can overpower the tail rotor. Let's say you stick a 30hp motor in the example above - much more than what's needed in normal conditions. This will give you an extra margin of safety and maybe avoid a LTE situation. It's there if you need it. Unless the battery is flat, that is

Last edited by AdamFrisch; 8th Sep 2010 at 07:37.
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Old 8th Sep 2010, 07:48
  #64 (permalink)  
 
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With only have 50 more years left of oil in the world ... we need to come up with something fast!
Says who?

Oil reserves are plentiful, says Aramco chief | IBTimes

Just another fallacy like global warming!

Did you know that there are billions of barrels still completely untapped here in the US, Canada, Russia, Indonesia and Africa!

Nice day man!

HM
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Old 8th Sep 2010, 07:52
  #65 (permalink)  
 
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I own a model helicopter with a Brushless motor, and I still don't believe it.

That motor only replaces the TR gearbox. The TR gearbox of an R22 is pretty light, i doubt it weighs more than 2kg.
You still need the power regulator, cables, and mainly - a 15kW generator and some decent size buffer batteries.
Not to mention that the motor, like all brushless motors of comparable size/performance i have heard of, runs at high RPM. So you would still need a 3:1 reduction GB.

The TR thrust in helos is limited through the pitch angle of the blades to protect the drivetrain, the TR itself and the tailboom. If one wanted a stronger tailrotor, these components need to be made stronger. That problem doesnt change with an electric one, except you'd need to beef up the motor and generator instead of the drivetrain.

10-15% of the power to power the tail rotor in its most extreme condition?
A lot of books say up to 30%. I don't know though.

I think lot of RC flyers see the amazing performance they can get out of electric RC helos, and underestimate the problem of scalability.

Last edited by lelebebbel; 8th Sep 2010 at 08:04.
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Old 9th Sep 2010, 02:29
  #66 (permalink)  
 
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Says who?

Oil reserves are plentiful, says Aramco chief | IBTimes

Just another fallacy like global warming!

Did you know that there are billions of barrels still completely untapped here in the US, Canada, Russia, Indonesia and Africa!

YEAH! Right!

You are gonna believe in some rich saudi bizz man with his legs tied to oil companies stocks that just writes an article out of nowhere...

And you think the Americans will let the ''untapped'' oil be tapped after what just happened in the gulf? Don't think so.

And don't forget about China, India and Brazil were they are booming and starving for more and more oil after each year.
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Old 11th Sep 2010, 18:42
  #67 (permalink)  
 
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The future of electric power in VTOL craft is more than the simple replacement of a gas engine with an electric motor.

It is about the ability to provide unique enhancements, which today's reciprocating and turbine drives cannot provide.


Dave
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Old 12th Sep 2010, 11:32
  #68 (permalink)  
 
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Another issue with this proposal is that you would get lag in your anti-torque control. Direct drive tail rotors work on small model helicopters because the tail rotor has so little inertia it can change speed really quickly and you don't get any control lag. On an R22 sized helicopter, I imagine there would be a noticable lag and on a significantly larger helicopter, I can imagine it would be difficult to control.

Another issue is that with vibration and fatigue. One of the reasons that helicopters are designed with a specific main rotor and tail rotor RPM is that it makes it a lot easier to do the vibration analysis and ensure the helicopter doesn't have any nasty resonances at the operating RRPM.
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Old 12th Sep 2010, 12:38
  #69 (permalink)  
 
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Deemar
Direct drive tail rotors work on small model helicopters because the tail rotor has so little inertia it can change speed really quickly and you don't get any control lag.
The speed does not change. The electric tail rotor would be at a constant rpm with collective pitch.
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Old 12th Sep 2010, 15:54
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cattletruck, you're right. It may be a race to see if effective electrical storage or a cure for cancer comes first.


Regarding an all-electric tail rotor, The current project involves the application of a torque-pitch coupling to a pair of small electrically driven main-rotors ~ Electrotor - SloMo. This feature should be applicable to a tail-rotor, also.

When the pilot increases the power to a rotor the torque reacts before the speed does. This increase in torque causes the collective pitch to automatically increase, then as the speed increases the torque and the collective pitch partially reduce.

Dave
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Old 13th Sep 2010, 01:03
  #71 (permalink)  
 
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hybrid Vs purebred

Interesting debate lads. While its true that some breakthrough in battery technology is needed to get anywhere range wise with a purist all electric chopper today, the technology is improving at 9% per year which means that batteries will be half the size for the same energy storage in just a decade even without a game changer.
Re hybrids. The auto industry have tweaked that's it's easier to move energy over wires than drive shafts, the Lexus RX400h has an all electric rear transaxle for example. A turbine (or two) running a poly phase alternator with wires to all electric MRB/TRB direct drives with minimal or no batteries is not science fiction as a concept.
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Old 13th Sep 2010, 05:28
  #72 (permalink)  
 
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Originally Posted by Dave Jackson
When the pilot increases the power to a rotor the torque reacts before the speed does. This increase in torque causes the collective pitch to automatically increase, then as the speed increases the torque and the collective pitch partially reduce.
Dave,

I think you should revisit that explanation

So the collective pitch automatically increases as a result of increased torque: what sort of helicopter are you talking about?
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Old 13th Sep 2010, 09:03
  #73 (permalink)  
 
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Squeaks

So the collective pitch automatically increases as a result of increased torque: what sort of helicopter are you talking about?
A governed, gyro stabilized electric (fly by wire) tail rotor would do just that.
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Old 13th Sep 2010, 09:21
  #74 (permalink)  
 
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An electric tail rotor should be safer too. For example you could have the ability to switch it off in flight if for example you had a "jammed pedal"
In fact why don't they do that now, without waiting for the all electric helicopter to come along?
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Old 13th Sep 2010, 17:49
  #75 (permalink)  
 
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Just came across this



Havent really had time to look every little thing up but first impression.. Very cool. We are lucky we have these stubborn scientists and engineers.

Im gonna look this stuff up a bit closer but its looks promising indeed..

Last edited by Senior Pilot; 13th Sep 2010 at 20:48. Reason: Embed YouTube link
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Old 13th Sep 2010, 18:36
  #76 (permalink)  
 
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I think you should revisit that explanation

So the collective pitch automatically increases as a result of increased torque: what sort of helicopter are you talking about?
Squeaks,

The specific Torque-Pitch Coupling does not exist in current helicopters. It is an innovation that is intended to simplify the pilot's control of very light recreational helicopters. The micro-light Electrotor project is an ideal testbed for implementing and playing with this idea; due to its low cost, the incorporation of other ideas, and the ability to initially fly it as a large R/C helicopter.


This is a revisit to the explanation, but it is a long and boring one.
DESIGN: Electrotor-SloMo - Control - Flight - Auto-Collective by Torque-Pitch Coupling - Overview
OTHER: Rotor Concept - Flight Control - Torque/Pitch Collective Rotor Hub


Dave
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Old 3rd Sep 2011, 20:01
  #77 (permalink)  
 
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Thumbs up World’s First Manned Electric Helicopter takes off

.
The World’s first manned flight of a 100% electric powered helicopter was conducted on the 12th of August 2011, after 2 weeks of tethered flight tests. This machine, designed and test flown by Pascal Chretien, for the French based company Solution F, is the outcome of a remarkably short development period that was initiated in August 2010.

This ultra light coaxial helicopter weighs 170-Kg empty, including 60 Kg of high performance air-cooled Li-ion polymer batteries that can deliver 43 KW continuous, and 52 KW peak. The craft weighs 247-Kg at takeoff and offers 10 to 12 minutes flight time. To save weight, conventional cyclic and flight controls were replaced by a weight shifting system, as well as a specific design for rotor inertia, and blade pitch. Collective and yaw are achieved via electrical flight controls.

An advanced MOSFET based feather light drive train offers astounding 87.5% end to end efficiency, from batteries terminals to rotor mast.

This helicopter is a demonstrator intended to pave the way for hybrid rotary wing aircraft and is a test bed for new technologies. Flight envelope expansion is ongoing.

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Dave
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Old 4th Sep 2011, 01:32
  #78 (permalink)  
 
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Dont know that I'd want to be sitting on 60kg of Li-Po batteries!
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Old 4th Sep 2011, 14:40
  #79 (permalink)  
 
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Hmmm... I wonder if that's why they put it into a ventillated protective box?
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Old 4th Sep 2011, 15:44
  #80 (permalink)  
 
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This machine has a really cyber look except for the rear stabiliser which looks a bit like a 5th century Chinese emperor's fan !
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