Hybrid or electric theory?

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BBerson

BBerson

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blane.c

blane.c

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BBerson said:
Moving toward hybrid:
www.avweb.com

AVweb VODCAST: Why Electric Airplane Designers Are Turning To Hybrid Drives - AVweb

Although some are in denial about it, the love affair with batteries for electric airplanes is, for the short term, on hold. To meet minimum performance, designers are increasingly looking at hybrid drives that may incorporate battery systems. In this AVweb VODCAST, Embry-Riddle’s Dr. Pat...
www.avweb.com www.avweb.com
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Hybrid seems logical to enable electric development while maintaining useful range.
 
blane.c

blane.c

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I know lets all forget about experimenting it is for morons. Color me moron. I don't care I'll experiment whether by merely thought or actual deed as I feel fit. Maybe what has been done over and over and over again is comforting to most, but it is the road that we would all be traveling by horse and buggy if a few hadn't experimented.
 
Dan Thomas

Dan Thomas

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blane.c said:
I know lets all forget about experimenting it is for morons. Color me moron. I don't care I'll experiment whether by merely thought or actual deed as I feel fit. Maybe what has been done over and over and over again is comforting to most, but it is the road that we would all be traveling by horse and buggy if a few hadn't experimented.
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I'm all for experimenting. Don't get me wrong. But of what use is adding weight, complexity, cost and failure points? We already know it would work. I just think it's a dead end. IMHO.
I designed and built many production and test machines, but I thought them through and did some math beforehand. Didn't build anything that the numbers didn't justify. It had to make money, not lose it. Everything I built worked, most of it very well.
I have also modified machines to make them work better. I see room for improvement in plenty of places. One of my big frustrations was some of the wonky stuff in certified airplanes that could easily be improved if it wasn't for the STC cost and approval hassles.
 
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blane.c

blane.c

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Yes. Normal category certificated aircraft leave a lot to be desired, experimental category certificated aircraft have a lot more room for modification. So one of the many reasons I like the prospect of 3 or more engines, say you leave two of them normal and the third is an electric with batteries and a generator. More complexity yes, but it is it a safer way to develop a hybrid powerplant? I am sure there is conjecture, but it is certainly a way.
 
mcrae0104

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blane.c said:
Hybrid seems logical to enable electric development while maintaining useful range.
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Hybrid seems like an inefficient way to turn fossil fuels into thrust.

Chemical energy -> heat -> kinetic -> electrical energy -> chemical (battery storage) -> kinetic -> thrust?
 
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slociviccoupe

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If interested in hybrids look at honda insight. The first generation one. I have one. But its pathetic 988cc 3 cylinder that makes 70hp WITH the hybrid ima motor. I carry around 90#'s of lto batteries that are only 22ah and a pack that is 72 cells in series and about 196vdc.
Now i have done current and voltage hacks. And even with the upgraded pack and modifications the combo now makes about 100hp you can almost drain the whole pack in about a few miles wide ipen that would be similar to climb. Once you got to cruise the controller will start to background charge the pack. There is the motor drive, a dc/dc converter, 2 computers for the hybrid system, a relay board with contactor and fuses.

The whole car weighs 1600# and is made of aluminum. The hybrid motor between ice and trans is capable of 15kw of power.
Honda also has a v6 version which could be adapted to other engines.

From messing with this stuff there is no way you can do it and keep weight down because of the batteries. Also you have to have 200+ vdc to do anything meaningfull.
 
blane.c

blane.c

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Hybrid is like the dirt road short cut between two highways, not very efficient in itself but the quickest way to change direction of travel. If you like the road your on stay off the short cut, if you want different scenery you may have to get a little muddy.
 
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rv7charlie

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I have a love-hate relationship with physics-related puzzlers; the obvious answer is often the wrong one. I also enjoy any discussion that includes the word 'never', particularly when looking back on it from a later date (when I'm *not* the one who used the word).

It's obvious to everyone that converting repeatedly among various energy types costs efficiency, and it seems obvious that any system that does that will be less efficient than one that doesn't.

Anyone know the most energy-efficient way to transport mass designed by man? Prize is 15 seconds of HBA fame.

Charlie
 
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slociviccoupe

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My thoughts on hybrid is its great for range where battery power isnt enough. Dont have to rely solely on electric. Dont have to carry as large as a battery pack. Its good for a short burst of assist but you are limited by the size of your pack.

The downfall is the ice engine is generally sized on the small side, uses the electric assist to make up for the lack of power. Then uses the ice engine to just maintain low power cruise and recharge the pack.

In an aircraft there is no chance of regen working. On my insight with the 30% current hack that gives boost in power also works the other way and gives 30% more regen braking. Its enough it fedls like your pushing on the brakes. I can slow the car just by pushing the regen brake button ive added and barely use the brakes except for low rpm low speed. Trying to do this on aircraft hoping the prop will windmill just wont happen.

And the only seeies hybrid i know of ate locomotives but they run the diesel at its efficient opperaring speed and it rarely has to stop. And the generaror and traction motors are huge.
 
BBerson

BBerson

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slociviccoupe said:
If interested in hybrids look at honda insight. The first generation one. I have one.
Click to expand...
Almost bought an Insight. Decided to stick with my antique Honda CRX's that are almost as efficient but half the cost to buy. And I can work on them sometimes if needed, buy rarely need work.
Instead of both IC engine and one electric, I would prefer two IC engines that start and stop as needed.
 
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rv7charlie

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The hint is in the subject matter. The most fuel-efficient transportation machine I can find is...a hybrid. Diesel-electric locomotives can haul 1 ton of freight 473 miles on a gallon of diesel, or 468 passenger-miles per gallon.

My point is that mission matters. Few of us would think that it would make sense to build an RV or other light plane and try to do a hybrid in it. But, like the designers who discovered the extreme efficiency of diesel-electric to move extreme mass, smart designers have seen the potential of 'distributed propulsion' in the STOL/VTOL arena. Pure helicopters are probably the most efficient at pure vertical lift, but are horrible for cross-country transport. Distributed propulsion (multiple props) can approach helicopter efficiency at vertical lift (through large disc area/mass flow), and can be quite efficient in cross-country performance, but it's totally impractical to put eight or ten combustion engines on a relatively small airframe. Electric motors have great power/weight, but batteries are still unreasonably energy 'un-dense'. Enter the hybrid...

Charlie
 
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