Electric tail rotor; an alternative?
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BTW RIPS is an example where industry has moved to make helicopters more viable. It being power hungry is exactly my point.
The technology is here, the engineering is possible. The question is whether the economics will move us in this direction or elsewhere.
The technology is here, the engineering is possible. The question is whether the economics will move us in this direction or elsewhere.
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And for others it allows them to operate in conditions not previously possible and therefore increasing usability of their asset. As a Customer, you take your choice.
Except that it is not reliable so you can end up committed to an IFR transit in icing conditions and then find yourself without ice protection - have you seen how many pages of malfunctions there are in the 139 QRH just for IPS?
And you lose a valuable vibration absorber which can cause AP/AFCS problems.
Just the sort of issues you want with an electric TR..............
The idea that something is better just because it is electric and new is just fanciful. However, if the advances in electric motor and battery technology were as fast as computer growth and processing power, we might see some viable alternatives but we still struggle with generation and storage for electric power.
How well are electric cars going to do in UK with a National Grid generating system that creaks at the seams on a still winter morning when consumer demand is high and generation output maximums are reached?
And you lose a valuable vibration absorber which can cause AP/AFCS problems.
Just the sort of issues you want with an electric TR..............
The idea that something is better just because it is electric and new is just fanciful. However, if the advances in electric motor and battery technology were as fast as computer growth and processing power, we might see some viable alternatives but we still struggle with generation and storage for electric power.
How well are electric cars going to do in UK with a National Grid generating system that creaks at the seams on a still winter morning when consumer demand is high and generation output maximums are reached?
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Originally Posted by [email protected]
The idea that something is better just because it is electric and new is just fanciful. However, if the advances in electric motor and battery technology were as fast as computer growth and processing power, we might see some viable alternatives but we still struggle with generation and storage for electric power.
Out of personal interest what rate of RIPS failures are people experiencing?
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But surely the question here is: why add complication to replace a well proven, simple mechanical tail rotor system that has proved very reliable for decades? It's worth bearing in mind that many tail rotor failures have been caused by external damage - these failures will still occur on an electrically driven system. In my experience (having been flying helicopters for a living for just coming up to forty years and fixed wing for some years prior to that), the items that have proven most unreliable on all the aircraft I've flown have mainly been electrical or electronic. Same with the road vehicles I've been driving since the 1960s. Water ingress is a perpetual issue as well as mechanical ones. Well designed gearboxes are very reliable indeed because they are so simple. Electric motors and generators are not so reliable and need more maintenance.
As far as "saving the environment" goes, noise reduction has been mentioned more than once. From what I've seen very recently, relatively straightforward innovations in rotor blade design seem to be a very good way forward.
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Real advantages may be gained in new designs where the geometric constraint of a TRDS doesn't apply. However see my previous response on all electric, that step may never come.
Originally Posted by [email protected]
dClbydalpha - that is my point, you have replaced a well functioning mechanical system (TR drive failures are rare) with an electric one which is just as likely to fail, so what is the advantage?
Petit plateau - but how much do the TESLA batteries weigh?
Petit plateau - but how much do the TESLA batteries weigh?
You can go further and propose to relocate the prime mover to wherever is convenient in the aircraft (i.e. low rather than high, or whatever) and put an electric drive on the main rotor(s) with an electrical transmission. Sort of the helicopter equivalent of a diesel-electric ship main propulsion, for much the same reasons. As a further refinement you then only need to put a few small/light batteries in the system and you can run the prime mover over a much narrower rpm band and still handle transient peak power loads; such a system typically has a better fuel economy. Taking an approach like this might be interesting if folk are having problems designing gearboxes, which I understand they are. Tilt wing transmissions are also complex and heavy and have awkward failure modes.
This is an interesting time to be a designer.
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As in " may you live In interesting times" 😁.
The ETR generation is not exclusive with the rest of the generation system. For a lot of the time the ETR will not be at peak load, when it is, other systems may not. A thorough ELA will show this and it may be that the weight penalty for RIPS can be shared with ETR, just a thought?
In my opinion I wouldn't go anywhere near electric main rotor for a conventional setup.
The ETR generation is not exclusive with the rest of the generation system. For a lot of the time the ETR will not be at peak load, when it is, other systems may not. A thorough ELA will show this and it may be that the weight penalty for RIPS can be shared with ETR, just a thought?
In my opinion I wouldn't go anywhere near electric main rotor for a conventional setup.
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Real advantages may be gained in new designs where the geometric constraint of a TRDS doesn't apply. However see my previous response on all electric, that step may never come.
If it's not a good idea for the MR, why is it such a great one for thew TR?
Everyone would like to see a helicopter replacement that looks like a scaled up drone or quadcopter but to give it a useful payload is a long way from fruition.
Crab, my initial post at #12 explains why it may be good idea.
A fenestron type ETR could be stopped in forward flight and yaw control achieved by a simple rudder. Massive increase in component life and reliability.
in the event of engine failure, any yaw in the descent could be controlled by rudder. The ETR would automatically spool up quickly under battery power for the vinegar strokes at the end.
Under normal ops, a conventional variable pitch mechanism would be used.
If made as a 'smart' system, the AW169-type failure could be mitigated by computer controlled reversal of direction of rotation with variable RPM to effect emergency yaw control. All of this is technically feasible today. If the pedals were driven to full deflection and held there, an ETR could be computer controlled to lock the heading. Heading could be managed by autopilot-type hdg bug on the HSI for example. Any excess rate of rotation could trigger a heading lock function.
Food for thought, or just fantasy?
JJ
A fenestron type ETR could be stopped in forward flight and yaw control achieved by a simple rudder. Massive increase in component life and reliability.
in the event of engine failure, any yaw in the descent could be controlled by rudder. The ETR would automatically spool up quickly under battery power for the vinegar strokes at the end.
Under normal ops, a conventional variable pitch mechanism would be used.
If made as a 'smart' system, the AW169-type failure could be mitigated by computer controlled reversal of direction of rotation with variable RPM to effect emergency yaw control. All of this is technically feasible today. If the pedals were driven to full deflection and held there, an ETR could be computer controlled to lock the heading. Heading could be managed by autopilot-type hdg bug on the HSI for example. Any excess rate of rotation could trigger a heading lock function.
Food for thought, or just fantasy?
JJ
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Originally Posted by [email protected]
Those already exist in the form of NOTAR, Twin rotor (Chinook) and contra-rotating MRs so it's not exactly ground breaking.
If it's not a good idea for the MR, why is it such a great one for thew TR?
Everyone would like to see a helicopter replacement that looks like a scaled up drone or quadcopter but to give it a useful payload is a long way from fruition.
If it's not a good idea for the MR, why is it such a great one for thew TR?
Everyone would like to see a helicopter replacement that looks like a scaled up drone or quadcopter but to give it a useful payload is a long way from fruition.
I thought the reason to avoid the MR was covered in my earlier posts. That would be close enough to the all-electric aircraft, which I don't believe will look like a helicopter, so no point going down that branch - even if a continuously variable rotor has its attractions.
Quad, Quad tilt ... who knows what will emerge over the next 10 years?
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I don't know for sure but I doubt it. I assumed they rely on the multiple motors for redundancy, but I could be wrong.
Here's a bit more info on the RR one which they say could be flying in the early to mid 2020s.
https://robbreport.com/motors/aviati...rough-2806843/
And NASA.
https://data.nasa.gov/dataset/Hybrid...enge/6x4v-g98n
Here's a bit more info on the RR one which they say could be flying in the early to mid 2020s.
https://robbreport.com/motors/aviati...rough-2806843/
And NASA.
https://data.nasa.gov/dataset/Hybrid...enge/6x4v-g98n
Last edited by gevans35; 5th Dec 2018 at 15:50.
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I'm not sure there would be a need. I can't recall whether Project Zero was.
Last edited by dClbydalpha; 5th Dec 2018 at 17:27.
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I'll let you know how my trial runs go when I electrify this thing.
I'll let you know how my trial runs go when I electrify this thing.
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If the pedals were driven to full deflection and held there,
Are you unable to see the advantages of an ETR or is it having assessed it judge it isn't worth it?
Millions of hours flown with the conventional tail rotor in all aspects of the helicopters versatile roles and the number of TR failures and malfunctions is very small.
One crash with an as yet undetermined cause but some form of TR issue and you are proposing ETR as the saviour to that scenario and ignoring the realities of system failure/loss of power in the ETR, not to mention that many of the solutions, such as jelly's, ignore the amount of time many helicopters spend in the hover as opposed to the high speed cruise.
Keep on with your blue-sky thinking but I will be surprised if we see ETR in the next 10 years at least.