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Solar Chargers

Absolutely more blades equal more drag. But more blades also provide more torque at a lower speed.
Either way, my 6.4 powerstroke didn't seem to notice. ;)

Compared to the trolling motor props, this prop was much smoother and quieter.

For the relative slow speeds of a cub, I don't think it's a concern.


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250mm I believe. 9 7/8 inches diameter. Prop pitch unknown.


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If you get the opportunity will you please place a protractor on the blade at the tip? Or alternatively show a picture of the blade looking towards the hub? I think that I can make one similar to that with some plywood. When laying flat how high (thick) is it?
 
So in conclusion, for the experimental non-electric guy that wants to never have to recharge his battery or wants to run bigger panels and lights....

Alternator and regulator: $100
Vetus 250mm SET 0090 thruster prop: $170
Lathe turned arbor for prop and alternator: TBD.
Mounting bracket and wiring: owner designed and fabricated.
Weight : 4 lbs +/-

Value? To me it will be worth it long term.


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If you get the opportunity will you please place a protractor on the blade at the tip? Or alternatively show a picture of the blade looking towards the hub? I think that I can make one similar to that with some plywood. When laying flat how high (thick) is it?

Pete, it's a complex prop. Somewhat like a Q-tip it has a variable pitch to each blade. Tip is pretty flat and the root is closer to 45. The design is geared to high thrust and low noise.

If you can actually create this out of plywood, you'd be a heck of a woodworker!! OK maybe more of a furniture maker.

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Thanks, Those pictures tell me a lot. I expect the variable pitch as it needs to decrease at each station as it moves out from the hub. Each segment of a blade needs to move through the same distance as the other segments through one rotation. The circumference increases as the diameter increases so the pitch must decrease moving outboard. I'm not an ace woodworker by any means. It's more of a challenge to myself than anything else.
 
Sounds about right. I tried the next size down, a set 89, (7") and output is substantially less but a good option for smaller loads. But, you have to kick start it again, at least on the ground.
80 - 4A
90 - 6A

It's basically half what the big prop puts out.
 
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Thinking about it for a second I'm going to see what it would take to get the small prop to spin up in the air. If you don't draw five or 6 A constantly the small prop would really be ideal.

If you're flying slower or shorter trips or simply higher loads the large prop would be the obvious choice.

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Based purely on observation in the mirror, sound and feel, I believe they're actually very efficient propellers.


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Pb,
I've been thinking about the prop size. Were you actually able to test it at 90? And did you get it to 90 without it starting to turn by itself? That output of 6 amps at 90 should get up to 8+/- at 100+. That's more than enough for me. Do you think that an 8" prop would be a good/better compromise? I would think that if it were placed in the prop blast at landing gear distances, the blast velocity ought to be about 100+/-. It should start to turn when the throttle is opened for take off. If the 7" prop will self start in the prop blast, then it should be large enough.
 
I tested both props on the truck. The 0089 will not self start, and the 0090 will start at 45.
I am milling new shafts to work with the props without using hand milled plastic bushings, so I can test it on the cub.
There are a few theories about prop blast. One is that the blast should spin it right up center mounted on the gear.
The other theory is that the airflow from the prop isn't much better and perhaps more pocketed. Consider rain on the windshield and how little it "streams" away.

Since AG planes can run a pump with airflow, I hope it's the first theory and prop blast is substantial.


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The other theory is that the airflow from the prop isn't much better and perhaps more pocketed. Consider rain on the windshield and how little it "streams" away.

Since AG planes can run a pump with airflow, I hope it's the first theory and prop blast is substantial.
The rain on the windshield is not a good example since the aerodynamics along the top of the cowl towards the windshield create a pocket of very little flow, particularly near the bottom. The air separates ahead of the windshield so that there is little blast directly on it.

The fan on the AG planes is directly below the firewall/landing gear area with a direct air flow path from the prop straight through towards the tail. Much straighter uninterrupted air flow.
 
So the 7" 0089 prop self started in flight? Where did you mount it, at the center of the landing gear V?
 
Yes. I propped it the first takeoff and it stayed running at idle. After a fuel stop idle must have lower on the tar and it didn't stay running. But it started in flight or on takeoff. Not sure which.


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Yes. I propped it the first takeoff and it stayed running at idle. After a fuel stop idle must have lower on the tar and it didn't stay running. But it started in flight or on takeoff. Not sure which.


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What kind of loads have you tested it with? And at what airspeeds?

Web
 
First flight - posted while flying.
Small loads - Garmin radio, iPhone and iPad charging was all I could load it with.
Didn't get a chance to measure amps till late in the flight, consistent 2.16-2.17 at that time, at 85-90 indicated. I expect if everything was dead and I had a big light going the regulator would pass more on.


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You'd have to turn the whole unit around Pete. Or rework the prop. I want replaceable parts off the shelf.
This will work perfect for my needs, based on the 3.5 hrs today.


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Okay, trying not to duplicate posts, but it's been dragging on so I'm going to post up some info and try to start wrapping it up.

Somewhere earlier in the thread was a post with dynamo and regulator costs.
I am using the Vetus Set 0089 prop, which is a 7" DIA. I have also tested the Vetus Set0090, which puts out over double the amps and a good choice for a heavy user. If someone wants one of these, let me know as I can get you better pricing.

I also turned out two custom arbor's to accommodate mounting of the above propellers. Again, let me know if I can help get you one.

The dynamo comes with output test results, of which I'll post the results below, as I expect they are typical.
According to the report, output starts about 1800 rpm, and jumps to 6 amps immediately.
Data shows 5A out at 1600, and progressive up to 18A out at 6000 rpm.

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The smaller prop working is probably best for my use as it's a self-limiting governor in terms of output. I'll never be able to fly fast enough to see 3-6000 rpm, and therefore the regulator only needs to deal with an input of under 12-16A in theory. I believe it would give me 5-8A currently if the demand called for it, perhaps as much as 10.

As I have the battery box under the seat, and good space on the box to mount the regulator, wire runs from the dynamo straight up to the regulator, and then via a breaker to the battery will all be quite short. One wire run up to the panel for a Regulator(GEN) breaker switch, and the INOP light.

The schematic has some redundancy for most, but due to my underseat battery location I already have a box mounted battery switch that kills power at the seat.

Gen Cir 3.png


On a side note - anyone use their bluetooth a lot and find their ANR headset dies early in a flight, with no spare AA's? FYI, they make USB powered battery chargers. And you've already installed that nice double USB and voltmeter plug, right? Well, if you mounted one in your underseat battery box as well, now you have a place to keep a set of AA batteries charged and ready for the next change.

...May the batteries stay charged with you.
 

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Quite an impressive project Farmboy! You just don't quit, and it looks like you are going to pull it off.8)

Speaking of solar (the original title of this thread before it morphed into wind power), here's a shot of 8 large (3480 watts each, so 27,840 watts total) arrays I fabricated in my shop and then trucked to the job site. these are designed to be lifted by a boom truck or crane, and will be in a couple days by me. The vert poles are already set in concrete, the final setting will go quick and easy, as long as the wind doesn't blow, and the welder, I have yet to meet, and I get along. And yes, I did expect to be able to land in the field above the job site, the owner is the guy I'm working for and it's EXPECTED that I will at some point land there, (right uphill from that drainage ditch, hard to tell but it's about a 12% grade), I tell my customers that there will be no extra charge for me flying in! The steel pipes in concrete make perfect tie down points.
 

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I'll have to post up some photos of the solar landscape that Vermont is turning into.


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Yah, not much farm land here anymore in a state that has had fewer than 10 days of sun in the past 10 weeks.
 
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