Pitch control diagram

[willib]

I'm really stuck on this idea , cant get it out of my head.

http://www.otherpower.com/images/scimages/2965/pitch_control.GIF

the servo could be PIC controlled and powered by a small set of spinning coils rotating against a fixed set of magnets .

i got the idea for the connections to the blades ,from the picture below .but i've added a third blade. thoughts?





Flux i would really like to see a photo of your pitch control mechinism.

[windstuffnow]

  A company called Ivo Prop makes an inflight adjustable prop using a small DC motor.   I've set up a couple of them on some small aircraft.  There is a steel shaft down the center of the composit blades which gets twisted.   It's a clever, simple system.   I've often thought of moving the design to wind turbines.   You can see the set up on http://www.ivoprop.com/inflightultralightmodel.htm .   I have one on a 2 seat plane and some damaged blades in the shop.   Damaged from a loose exhaust nut flying through it on take off.

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[Flux]

I didn't take any photos of mine, but I did save an early drawing that will give you some idea but it will be difficult to follow the mechanism to synchronise the blades without knowing something of the Elektro hub that I based it on.

Should be details on the net of Jacobs, Dunlite, Aerowatt and similar ideas, many tried it.

Not sure how it will come out on the screen but if you look in my files you can find it as a gif or jpg and if you load them and look at it bigger it should be ok.

Flux

[Flux]

This link should show a pitch control hub by JacquesM and there ought to be other pictures somewhere.

http://www.fieldlines.com/story/2004/11/11/8830/1379

[willib]

Ed , i dont see how they change the pitch of the blades , on these ?

http://www.ivoprop.com/images/electricpropsystem.JPG

[willib]

I see how that works, although they use three actuators..  when all you really need is one..

[willib]

I didnt find a pic of his pitch control ,close up , but his photo uploads are gone

[windstuffnow]

  The motor drives a screw drive, the gold part is a thimble that the steel inserts are connected.   What it does is pull the steel up or down to flex the blades.  The pitch change is quite dramatic, at full pitch it will bogg a 65hp engine.   I ended up having to put in end stops to keep the blade from going to far from one extreem to another.  It does a nice job going from extreem thrust for take off down to a nice load for fuel economy.   I only used that as an example to setting something up on a pivot instead of building a set of flexible blades.  It's really a simple system.

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[willib]

How do the blades pivot ?

How does pulling on the blades change the pitch?

is there a wire in the blades? are they hollow?

sorry for so many questions.

[windstuffnow]

  It has a steel rod through the center of the blade, cast into the composit.  Both ends of the steel insert has a 90 deg bend, the motor uses the lever to pull or push on one end of the steel arm which inturn twists the outer 90 flexing the blade to change pitch.

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[dalibor]

the french company "eoltec" is using similar control on their 2-blade system . something with opposite weight on axe of blade plus some kind of springer . nice pics can be seen on their site about it. www.eoltec.com

check out PDF broschures there

[Flux]

willib, if you are referring to my drawing, the things that you think are actuators are just weights. They look like pistons on the drawing but the thing is weight operated, there is no active servo.

Flux

[willib]

Yeah i see that now , thanks

[willib]

I looked at their site ,6 KW from 18+ foot blades is pretty good , they are able to hold the gen. at a constant speed by using mppt and Passive weight pitch control .

http://www.eoltec.com/Documents/Scirocco%20V02c_Eng.pdf

[elvin1949]

ED

Not many mechanics out there are there.

later

elvin