Let's talk about wind power

[johnny b]

GS...my apologies if you were offended by a little light hearted joke.

Since RATs are in use on everything from Boeings and Airbusses to Pipers and Cessnas, please enlighten me as to my aerodynamic error.
I've also seen hydraulic RATs used on small crop dusters to pump the poison at speeds lower than 85 mph.

 

[johnny b]

Spaceman:
"The airplane 'ram air turbines' use gravity (i.e. the plane falling out of the sky) to power it.  2nd law of thermodynamics (paraphrased): you will get less power out than you put in.  If you put a turbine in the airstream, you will get less power out than the power required to turn the blades.  It can be done but it will cost you gas milage.  One reason you haven't seen it done on cars and trucks is that an alternator is simpler and more efficient.

When I was racing (and I think NASCAR still does this) the alternator was driven off the pinion shaft on the rear axle.  Should be possible to make a system running off of the trailer wheels/axle.  Another option is to convert to 110V at the alternator, run 12 ga wire back to a battery charger.  Not real efficient, but if you do a lot of driving who cares.


 -- Spiff"



My goal was to keep it cheap...although I like your Nascar idea. I could easily upgrade (or add a second) alternator and run a big cable....but that could get expensive.

My thoughts on the RAT was producing a small amount of power (20 amps or so), with junkyard engineering, and realizing full well that there will be some drag costing a bit of gas mileage. So if it costs 30 or 40 amps worth of engine power lost to drag to produce 20 amps from the airflow, how much extra gas might that equate to?

I already deal with drag produced from a rooftop AC and a rooftop vent. If I was to build a test RAT to test the drag and it knocked my mileage down by 3 or 4 mpg I'd certainly scrap the idea. I think a 10 inch round scoop that allowed no flow thru at all would not affect mileage that much.

I'll test and report back....not a top priority so patience is requested.

 

[LeeRevell]

Keep your political opinions off the board.   :dodgy:  They seem to be as misinformed as the grasp you have of aerodynamics.  :huh:

Actually nothing wrong with Johnny's idea of a Ram Air Turbine.  We had them on a certain aircraft at my USAF base in the seventies.  The one used by the F-106 interceptor was about the size of a heavy duty truck alternator, to power a ten ton aircraft if the main power failed.   The idea is sound.  Sure, there wil be inefficiencies and losses.  Only direct testing will show how well it works.
it is a matter of choices.  Don't like the idea?  Don't use it.  Someone else may find it workable.
Some find solar not good for them  Some don't like gensets.  We all have different needs.
The "political" jibe was a bit over the top too.

 

[highdesertranger]

you can NEVER make power for free. it ALWAYS takes more power input then than power output. any wind thingy you put on your vehicle that makes electrical power is going to take more energy to turn then you will get out. just because airplanes use it doesn't mean doody. in fact airplanes only use it during an emergency. it is not out in the air stream all the time(it causes to much drag). it is only deployed in an emergency. https://en.wikipedia.org/wiki/Ram_air_turbine . if you think about it, if it would cause less drag then the power generated you would have just invented the perpetual motion machine. you my friend would be an instant millionaire. highdesertranger

 

[speedhighway46]

Flux capacitor, that's the solution.

 

[johnny b]

Again, my apologies for the joke....I live in DC so 'National News' is actually my local news....we are inundated with politics and jokes abound freely. I try to keep my political tongue in check on this forum, and will try harder in the future.

As far as the 'no free energy' argument....I'm well aware and have noted in my posts the acceptance of loss due to drag. The alternator we drive off our engines does not produce free power...it requires energy from the engine via a belt, and produces a loss in mpg (compared to running without an alternator at all).

The RAT analogy/example is just a possible design route due to its proven record.

Not trying to produce 'free' power....but wondering just how much 'loss' will be experienced from a small diameter turbine. If its a huge loss in mpg, then its a no-go. But if I can get 20 amps from a junkyard exercise, then hey, more power to me.

If I bought a second alternator that would also take power to make power, but a V8 would handle it OK, maybe cost a mpg or 2?? If I just tap into my existing alternator, I'd be increasing the electrical load on it therefore costing more power.

Yes, there is no such thing as free power. Solar is only free after justifying/amortizing? initial costs. Same with wind.
If I spend $1000 on a solar/battery set up, replace the batteries (2 T105s) at 5 years, and again at ten years then I've spent approx. $1500 or $150/yr for solar power.

So if I can supplement a few amps of current via the wind rushing over my trailer while driving at a 'minimal' cost in drag...well then I'll have utilized another source of 'cheap' power; not free power.

 

[highdesertranger]

hell go for it. obviously you are not paying attention to our advice. so just do it. after the wind turbine you can start on your wood gasification system. if you ask me you would be dollars ahead to just add another solar panel or two. highdesertranger

 

[TMG51]

As far as the 'no free energy' argument....I'm well aware and have noted in my posts the acceptance of loss due to drag. The alternator we drive off our engines does not produce free power...it requires energy from the engine via a belt, and produces a loss in mpg (compared to running without an alternator at all).

The RAT analogy/example is just a possible design route due to its proven record.

Not trying to produce 'free' power....but wondering just how much 'loss' will be experienced from a small diameter turbine. If its a huge loss in mpg, then its a no-go. But if I can get 20 amps from a junkyard exercise...[sic]...if I can supplement a few amps of current via the wind rushing over my trailer while driving at a 'minimal' cost in drag...well then I'll have utilized another source of 'cheap' power; not free power.

I don't have an answer to just how much loss, because I know that it doesn't matter how much. Whatever the amount of loss is it's going to be greater than the gain. Because that's how the physics work. You're talking about a closed system. The power going to the turbine is coming from the energy in your gas tank. There is going to be efficiency loss in every step of the way before that energy gets to the turbines and to your battery.

The reason they're used on planes is because those planes can use them via gravity and not only their own power (this is why I commented about if one could theoretically use a wind turbine on a vehicle only when coasting downhill).

You COULD get SOME amount of power out of a wind turbine on a moving vehicle. How much, I don't know or care, because it will be less than the power you put into it. If you want to do that just as a science experiment go ahead but you're neither making free energy nor cheap energy, just wasting gas.

Yes, an alternator also requires energy put into it to operate. You're free to take your alternator out of your car if you'd like to stand on principle there.

 

[LeeRevell]

TMG, you seem caught up in the idea of powering the vehicle with 'wind power' which is not the OP's intention.  It is really little different from the alternator concept - just another way to charge batteries by wind stream while driving, instead of or in addition to the alternator.  Just as valid either way.  Both have losses.  Both will work.  One may be more efficient than the other.  It sounds like an interesting engineering exercise.
In effect it is no different from the current idea of retrieving electrical power from the wheels while braking or going downhill in some hybrid cars.
So..... what is the problem?   :huh:

 

[TMG51]

TMG, you seem caught up in the idea of powering the vehicle with 'wind power' which is not the OP's intention.  It is really little different from the alternator concept - just another way to charge batteries by wind stream while driving, instead of or in addition to the alternator.  Just as valid either way.  Both have losses.  Both will work.  One may be more efficient than the other.  It sounds like an interesting engineering exercise.
So..... what is the problem?   :huh:

What OP was talking about was setting up a wind turbine when STATIONARY, which makes sense. What johnny b (and now you) are talking about is setting up a wind turbine while MOVING, which makes zero sense. Sorry.

 

[highdesertranger]

Lee I can't speak for TMG, but the difference as I see it is an alternator is a ready available bolt on part. a wind turbine, not so much. I told him to go for it. if he has got the money to throw away then fine. sometime I drive hundreds of miles to check out a gold area, only to find 5 bucks worth of gold. so if he wants to spend his money that way it's all good. I understand. highdesertranger

 

[akrvbob]

I like the idea of windpower, I think that every house should have one, like a tv antenna. On a van, the set up, take down and storage bothers me, surely there is a way to leave them set up and all you have to do is turn, flip or raise a pole.

Look at the link I provided above, it really is no big deal for him to set up and take it down. Literally 30 minutes or less.
Bob

 

[gadgetMe]

I am the guy that Bob did the story on at the first RTR, Man...  how the time flies..

The wind charger I use is the Air-X that were manufactured in Flagstaff Az. back then (the company has been sold since then)
The maximum output is 400 watts at 20 mph sustained winds (more on that Later) The startup wind-speed is 10 mph.

As for the battery bank I use solar with the wind to have a hybrid system (if you will) that way I can have the best of both worlds no matter where I am in the country, with  ever changing weather conditions. ( the worst weather conditions for making off grid power is  heavy cloud cover and no wind)

So, in a van application if you have a house battery, you can connect the wind charger to that battery.
The wind charger and others that are manufactured have built in charge controllers, so the connection is as simple as hooking up the positive and negative to the battery ( a large fuse is recommended)

As for mounting on my unit I have used 1 1/2 inch schedule 40 steel pipe cut to lengths the are handy for storing when it is torn down when traveling, each section is threaded on the ends (which was done at the local home depot) and I used threaded unions to be able to assemble it when stopped.

Last year I changed the steel pipe for aluminum tubing still rated at the schedule 40 strength. Reducing the weight by 2/3

As for electrical connectors I use Anderson Connectors Power X

I have seen mounts that use the weight of the rear tire on a plate to hold the pipe  steady and a mount on the rain gutter for the upper mount.

I use the charger as a auxiliary way to keep the battery bank charged, wind is never as steady as solar during daylight sunny days, most wind is not continuously sustained, so you have peak to no wind, but the best days that are sunny and windy.

The advantage for us is we get battery charging during stormy times, even in cold weather (when the furnace is running a lot)  at night
and on constitutive cloudy days.
 Works well in the desert areas, mid west plains, coastal areas, above tree line in the mountains, and large mountain meadows, and large lakes.

Disadvantages: can be some what noisy in high winds, does not work well in wooded areas, the wind swirls too much (cannot get a straight line wind)

For us I enjoy having it, The other thing is.. If you are bored just put it up and people will ask  "how does it work ?" Answer: when the wind blows

Cheers





http://www.powerwerx.com/anderson-powerpoles/housings-contacts/sb50-loose-piece-colored-housing.html

 

[johnny b]

TMG51: "I don't have an answer to just how much loss, because I know that it doesn't matter how much. Whatever the amount of loss is it's going to be greater than the gain. Because that's how the physics work. You're talking about a closed system."

So this also means that tapping off the alternator thru a solenoid and feeding the house battery is also a net loss...burning more energy in gas (to turn the extra load on the alternator) than the electric energy gained. What that ratio is I haven't a clue.
Obviously since so many have been doing this for years, the difference is very small...an acceptable amount, yet fulfilling the laws of physics.
Starting the vehicle and fast idling to charge up a house battery is definitely a very inefficient use of gas...in effect just a big V8 'generator'. The efficiency changes when driving the vehicle because now the engine and alternator are multi-tasking.

This air turbine idea was something I just thought was interesting a while back and then the mention of a vehicle mount in this thread sorta brought it back to mind. Since driving down the road the engine is already working hard to push the air around the vehicle, adding a bit of drag to get a bit of electricity may very well fall into a similar range of loss over gain as tapping off the alternator.

Only some testing will tell the tale...and I'm not gonna spend a bunch of money. First test will be to see how much the drag from a 10 inch 'bucket' affects gas mileage.


I certainly didn't mean to start a pissing match and I do appreciate all of the responses.

Oh, and I found the pretty picture...it was 'GizModo' not 'GizMag'.

 

[TMG51]

TMG51: "I don't have an answer to just how much loss, because I know that it doesn't matter how much. Whatever the amount of loss is it's going to be greater than the gain. Because that's how the physics work. You're talking about a closed system."

So this also means that tapping off the alternator thru a solenoid and feeding the house battery is also a net loss...burning more energy in gas (to turn the extra load on the alternator) than the electric energy gained. What that ratio is I haven't a clue.
Obviously since so many have been doing this for years, the difference is very small...an acceptable amount, yet fulfilling the laws of physics.
Starting the vehicle and fast idling to charge up a house battery is definitely a very inefficient use of gas...in effect just a big V8 'generator'. The efficiency changes when driving the vehicle because now the engine and alternator are multi-tasking.

This air turbine idea was something I just thought was interesting a while back and then the mention of a vehicle mount in this thread sorta brought it back to mind. Since driving down the road the engine is already working hard to push the air around the vehicle, adding a bit of drag to get a bit of electricity may very well fall into a similar range of loss over gain as tapping off the alternator.

Only some testing will tell the tale...and I'm not gonna spend a bunch of money. First test will be to see how much the drag from a 10 inch 'bucket' affects gas mileage.


I certainly didn't mean to start a pissing match and I do appreciate all of the responses.

Oh, and I found the pretty picture...it was 'GizModo' not 'GizMag'.

Best of luck!

 

[SoulRaven]

The drag of a wind turbine while driving should be considerably less than that of a solid box of the same size, because the turbine will allow air flow through it.

Even if the drag was the same as a solid box, who cares? The frontal mass would probably still be no more than that of a solar panel, or a rooftop cargo box, both of which people seem to find perfectly acceptable.

 

[LeeRevell]

What OP was talking about was setting up a wind turbine when STATIONARY, which makes sense. What johnny b (and now you) are talking about is setting up a wind turbine while MOVING, which makes zero sense. Sorry.

You either lack vision, or are simply on a different plane.  We will just have to differ.  I don't see the sense in your comments.

 

[GotSmart]

Noise is by far the biggest complaint along with the inefficiencies of low wind speeds. However, some of the new designs of both horizontal and vertical blades are addressing those issues. But like any technology, the 'better mousetrap' is out there waiting for the sales volume to bring down the cost. Adapting home/commercial successes to the mobile lifestyle can also be difficult.

On the issue of rooftop power while driving, I've investigated a bit and think an auxiliary power source could be done. I'm not talking about perpetual motion amounts of power but a small "Ram Air Turbine" that could give 20 amps or so into the system while on the road. Aircraft, both big and small use "RATs" in case of total loss of engine power.

This is an example of a RAT on a Cessna:



It is 8 1/2 inches in diameter and produces 6 amps at 28 volts at 85 mph.

I think something similar could be made from a small car alternator....experimenting to find the correct blade angles to produce the RPMs needed would be the biggest pain. I started investigating this because I did not want to run a fat ass cable from the front of my van all the way back into a trailer where my electric is.


I doubt the drag from a 8-10 inch fan in the air stream would be too much for a V8 vehicle. I mean if you want to talk drag, stick a commercial ladder rack and a couple of extension ladders on the roof...that doesn't stop a van in its tracks. 

Gizmag had an article (of course I can't find it now) that showed a concept of a half dozen 'ducted fan' style RATs mounted on a rack like an off-road light bar. Looked like a great idea, but alas there's that overwhelming dilemma of "demand" justifying investment.

First I want to apologize for my attitude yesterday.  My blood sugar had spiked~~~~  :blush:  and I do not play well with others when that happens.   That is why I waited until today to reply.  

The political "joke" hit a sore spot, but I will not address it in public due to board rules.  

The underlined part of your post is what I was referring to.  If you have a 12 MPG vehicle, and disrupt the airflow over it, that will cut down the MPG by 2 mpg.  (estimation from experience)  20% is a lot when you are driving 1,000 miles.  The blades would (by design) create a force that would mean the vehicle would need to produce more power to keep up the same speed.  

It is much more economical to utilize an existing system such as the alternator than to change the aerodynamics of a vehicle.  My solar system is designed to be low profile.  My gas mileage took a 1/2 mpg hit when I installed the rack, but is unchanged after I installed the panels.  (Other than the original -1/2 mpg) 

IMHO, with my years of experience and study, (for what it is worth)  :s By installing an upgraded alternator and quality cable / connector you would be money ahead over a RAT.  (Besides, it is not a good idea to go 85 mph on the freeway with a van or truck just to get 6 amps.)

 

[VanKitten]

Well,   I guess I wasn't clear.   No my plan was to set it up when there isnt sun, but wind instead.     Maybe if I get both...do both.   Never thought to try to collect energy with it while driving.    

I want to spend a fair amount of time exploring the Canadian maritimes, do not expect much sun.   I have also spend some time in the high desert of Colorado..I know how windy it is there.    Even in Florida, there are a number of windy, cloudy days during the winter.   I have though if I could have both going (solar and wind) it would mean having a nearly full function kitchen during those times.

 

[GotSmart]

Well,   I guess I wasn't clear.   No my plan was to set it up when there isnt sun, but wind instead.     Maybe if I get both...do both.   Never thought to try to collect energy with it while driving.    

I want to spend a fair amount of time exploring the Canadian maritimes, do not expect much sun.   I have also spend some time in the high desert of Colorado..I know how windy it is there.    Even in Florida, there are a number of windy, cloudy days during the winter.   I have though if I could have both going (solar and wind) it would mean having a nearly full function kitchen during those times.

The link Bob provided has the best information you will find on this site on wind.  

Your build, your way.     Let us know what you do so someone else can also learn.

http://www.cheaprvliving.com/installing-wind-generator/