First propeller turns of my 600W wind turbine

[Christophe]

Ah vomito

Sorry i didn't make the connection

[denis]

for the location it may not be on the top of you the best, if you have regular N winds for example, buildings that screen may leave a compressed wind corridor, hard, to explain to me day hui, (I'm not well)

[Christophe]

It's a temporary location ... looping made it clear

[Other]

Hello

Hello

I temporarily installed my rotor on the generator to subject it to the winds
The installation is not ideal at the exhibition level since it is in the middle of my yard
For the moment the voltage reached has not exceeded 6V (2 rpm) but I have to touch up the tips of the blades and wait for more favorable winds
I couldn't resist the urge to show you a first photo, even if the results are disappointing for the moment

In the background, my barn roof 100m2 at 45 ° due south for my next project. But this is another story

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I seem to see no twisting in the constant angle propeller? which seems high, risk of turning only with a fairly strong wind 20kmh
the part close to the hub is likely to be a little harmful to the weak wind, in a propeller it is the ends of the blades that must be well cared for. porch of the hub the tolerance is high, a pan to hide the hub increases the performence
a smaller step is preferable to exploit the weak wind


For balancing? not had too much problem
there is the static question (easy) and the dynamic question (not equal, blade width in precise extremity, leading edge and thin trailing point ..

Andre

[loop]

Bonsoir

Remundo wrote

Shouldn't you put your machine at the top of your roof, well anchored on the wall?

With your solar project, you could swing everything on the EDF feedback point, with 2 meters (one photovoltaic, the other wind)

I have already read that it is not recommended to connect a wind turbine mast to a wall, because of the vibrations generated by the rotation of the propeller.
On an old building like mine, I must take precautions before considering an installation on the frame. (Fastenings on silent-blocks?)
Otherwise you have to make a mast starting from the ground, higher than the roof.
A certain distance (100m) and over-height (10m) from the buildings is recommended, but this is not always possible.
For the connection to EDF, given the low power available, it is not even worth thinking about it
In addition, the EDF connection, the approved converter and the red tape does not encourage me to go this route.
For solar, I was talking about thermal collectors

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[loop]

Suites

Christophe wrote

) Wow looping I didn't know you had such a project in progress!
I guess the propeller is 100% Homemade (it looks like it's made of wood right?)

You must have missed the first episode
I put some photos on the realization of the 1st alternator (less powerful) and the manufacture of the blades for this wind turbine

https://www.econologie.com/forums/alternateu ... t4674.html

Denis wrote

for the location it may not be on the top of you the best, if you have regular N winds for example, buildings that screen can leave a corridor of compressed wind

I do not have a completely open location
It is certain that being near buildings can cause turbulence and slow natural flow
However, we can provide a robust material and we gain in length of electric wire, so in losses
Attaching to the top of the roof is possible, if it is easily accessible
I remind you that the legal height for the basket limited to 12m, otherwise you need a building permit
For the solar project in pre-study, I will talk a little about the other subject, experimentation and photos soon

https://www.econologie.com/forums/choisir-de ... 98-60.html

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[loop]

André wrote

I seem to see no twisting in the constant angle propeller

The twist is not very visible, but it does exist and respects the theoretical progression of the angle of incidence as a function of a Lambda chosen arbitrarily from 5.6
The progress of the twist is visible in the photos of their creation (link on the previous answer)

the part close to the hub is likely to be a little harmful to the weak wind, in a propeller it is the ends of the blades that must be well cared for. porch of the hub the tolerance is high, a pan to hide the hub increases the performence
a smaller step is preferable to exploit the weak wind

I haven't put a cone yet, I still have to make it
Actually I have to review the end of the blades which do not respect the theoretical profile NACA 4412, but it is more difficult to do it when the section is very thin
Regarding the pitch, I chose a fixing which allows to adjust it
Large step (low starting incidence) = easy rotation with torque but the speed of rotation level off
Small step (large incidence at start-up) = rotation from a certain higher threshold but the rotation is faster
For balancing, I did not notice anything abnormal, but until then the rotation speed was rather low

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[Other]

Hello

Actually I have to review the end of the blades which do not respect the theoretical profile NACA 4412, but it is more difficult to do it when the section is very thin

I work in metal airplane propellers which are a bit similar
the profile is not very critical on the performance, I saw propellers of Cessna 172 to the profile damaged by the sand and the tracks of drill, stones and the performance was not too degraded

The end of the square shaped blade is nefaste it must be softened the corners by a small radius to thin it with a small chamfer on the upper surface.

Andre
For twisting it is necessary that the angle of the blade versus the diameter be at the same pitch all along the propeller (although it is taxable near the hub. On an airplane propeller it reaches its real pitch only at 60cm in diameter)
I will try to find the steps and the dimensions of a propeller that I had to repair for a generator of sailboat

[loop]

hi Andrew

For the comparison between the airplane propeller and that of a wind turbine, I would say that the major difference is in the direction of flow of the relative wind compared to the profile:

In the case of an airplane propeller, the profile is "active", in other words, the forced rotation of the blade creates a lift oriented in the direction of travel.
The upper surface is forward, the lower surface opposite

For the wind turbine, the relative wind is created by the displacement of the air mass relative to the support
The parasitic lift (in this specific case) is in the same direction as the flow
The lower surface is forward (side where the wind comes from)

In both cases the relative wind is the sum of the flow perpendicular to the plane of rotation (constant if wind or fixed speed of displacement) and the tangential speed at a point on the blade.
This tangential speed is zero at the center of the propeller and becomes maximum at the end of the blade, which explains the twist necessary to guarantee a constant angle of incidence (in theory)

To reduce turbulence at the blade tip, there are solutions that come from aeronautical research
here are some photos









Link to a site that deals with wake turbulence (Christophe found it for the subject Chemtrails)

http://www.minix.fr/anti-vortex_actuels.php

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[loop]

Bonsoir

After some improvements to the blades, their balancing and the addition of a rudder, today's sustained wind (around 30 km / h, peaks at 50?) Made it possible to reach 18V when empty.
In charge on a 12V bulb I only got 20w, which is relatively low for a wind turbine of this size.
I would be curious to know what an equivalent commercial wind turbine delivers as power for an identical wind.
Little photo of my beast today



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