Author Topic: Blade station templates for "otherpower" style blades?  (Read 14882 times)

0 Members and 1 Guest are viewing this topic.

Offline shawn

  • Newbie
  • *
  • Posts: 24
  • Karma: +5/-1
Re: Blade station templates for "otherpower" style blades?
« Reply #15 on: May 18, 2012, 03:52:43 am »
Don't  think about it to much, most of us just get to fussy get that chainsaw out and go for it when its close enough balance and fly it.
1166-1
these are 4 meter diameter

Offline tomw

  • Not as bad as you might think
  • Senior Moderator
  • Hero Member
  • *******
  • Posts: 739
  • Karma: +35/-0
  • hoplophobic people will fear my lifestyle
    • Zubbly's photos!
Re: Blade station templates for "otherpower" style blades?
« Reply #16 on: May 18, 2012, 09:46:31 am »
I just tried to post a long and detailed set of questions on my confusion on how to do the one side blade carving with a chainsaw.

Damned server ate it. No time to do it all again.

So a simple question:

How do I duplicate this process with a chainsaw:

http://www.fieldlines.com/index.php/topic,146535.0.html

The youtube video:


I am just not seeing how to set it up. How he gets his numbers is a mystery "from the book" which I may or may not have.

Thanks.

Tom
Do NOT mistake me for any kind of "expert".

( ?° ?? ?°)


24 Trina 310 watt modules, SMA SunnyBoy 7.7 KW Grid Tie inverter.

I thought that they were angels, but much to my surprise, We climbed aboard their starship and headed for the skies

Offline oztules

  • Forum Advisors
  • Hero Member
  • ****
  • Posts: 1177
  • Karma: +105/-8
  • Village idiot
Re: Blade station templates for "otherpower" style blades?
« Reply #17 on: May 18, 2012, 06:17:29 pm »
Tom,
I think for these purposes it is sobering to reflect on the difference between perfect and rough as..... and it is not much at all.

The blades you had originally were probably from the Dans stable of blades, and to this end they "got it" and went for sturdy and simple, and still gave very good service.

For the enthusiast, getting the blade calculator and doing it perfect is more for themselves and less for the power generation process. The furling on these things is woeful, and makes perfect blade carving a academic thing, rather than practical..... so.....

Firstly, get an idea of what Melonos is talking about with his single jig system. Once you have that in mind, maybe whittle a little 12 inch prop just to see it in real life....... like just  sitting on the porch with the mutt, a stick and a whittling knife.

I depart from Melonos at this point. I would NOT cut out the blade shape (root to tip profile) as this limits your ability to fix the blank board in your jig.By all means draw it in in order to get an idea of where your end profile will be..... but  cut the whole plank as one with the chain saw.... then cut the root to tip shape.

Now you have seen the result from whittling, you can see one side  ( the lee side) will stay virtually flat, and we won't need to do anything with this side until later. Normally the windward side has a flat leading edge..... but this is opposite thinking with this method.

The windward side is what we now need a jig for.

Using the Dans idea, just draw a shape on the end grain (outer tip) with the profile of your blade.

Now we know from the video, the spine will be flat on the table/jig, and so ALL measurements will be from here. The thickest point will be spine, and it will be 1/3rd in from the leading edge.... whatever the chord is at any point.

We want the thickness to be about 1/8th the chord at any point, and that will be from the spine.

You want about 3 degrees for the end profile to drop, about 6 degrees halfway down, and whatever makes you feel good at the root. It will make no appreciable difference what you do here with an axial flux, as start torque is nil.

Doing this you can see the blade virtually describes itself at any point. The cord will dictate the thickness.... simple.

The chord is a simple tip to root area straight line.... and the degree angle is the only thing to make you think a abit, but this picture from Melonos
1167-0

says it all. Take it steady and try to fathom it, and it will come if necessary......
Draw the tip profile on the tip getting the 3 degrees offset, then do the same (on the end too)  with the 6 degree mid point... simply get the midpoint from your "tip drawing of it's position) and place that offset at your halfway point.... and draw the line.... and down to the root as you please.... your done.

....throw the blade calculator down the toilet.... it's only for perfectionists, and will do little if any good at all. Matching the load a bit better will make much more difference, as will SOC of the bank etc..... it's no big deal.


If you mark this information on the sides of the blade blank, you will end up with really only one line on the leading and trailing edge of the blank... always referenced from the lee side which will remain flat on the table/jig.... THE SPINE TOUCHES THE TABLE ALL THE WAY ALONG..... ALWAYS.

Those two lines show where the timber will be removed. It will be on the windward side of that line on each side...... so we now only need to know what the blade depth of the chainsaw will be, and make two boards on the sides for the chainsaw to follow.... ie our jig.

If we now mark a line to reflect the offset that the blade arrangement will use.... thats where these rails/boards need to be.

Now you can see that the blade will travel on the jig board, and actually cut along the original line you marked.

It takes some mental gymnastics to get the hang of....... just like the gravity furling did... but the moment you do one, it all falls into place.


I know the purists will go bippy , but thats what will work. The next set you can get all purdy with perhaps.



..................oztules
Flinders Island...... Australia

Offline luv2weld

  • Newbie
  • *
  • Posts: 17
  • Karma: +0/-0
  • No Personal Text Set by User
Re: Blade station templates for "otherpower" style blades?
« Reply #18 on: May 19, 2012, 09:04:02 am »
Tom,
I am trying to put together a set of instructions for making the jigs. The weather is working against me. I need to take the
pictures outside and we are having high winds and rain. So it may be another day or two before I get the pictures done.
If you PM me I will try to explain whatever you need.

Ralph
The best way to "kill time" is to work it to death!

I wouldn't need to manage my anger if people would learn to manage their stupidity!!

Offline tomw

  • Not as bad as you might think
  • Senior Moderator
  • Hero Member
  • *******
  • Posts: 739
  • Karma: +35/-0
  • hoplophobic people will fear my lifestyle
    • Zubbly's photos!
Re: Blade station templates for "otherpower" style blades?
« Reply #19 on: May 19, 2012, 03:03:37 pm »
Oz;

So, another question as this comes together in my tiny cerebral cortex:

If the root is of little to no importance in an axial dual rotor why have it 9 1/2" wide? The originals were 9.5" wide and 1.5" thick.

My root needs a mounting tang 6.5" wide and 10 inches long.

Wondering if I can just carve it from a 2X8 (7.25" wide) rather than a 2X10 (9.25" wide) if it will work well enough? I notice these axials are often spinning in winds lower than they need to actually push any amps so the wide root doesn't likely enter into the equation. But then there is the strength part?

Seems here any dimension lumber over 2X8 is only available in fir but lighter "white wood" is available up to 2X8.  I know I am over thinking the plumbing but I have dreaded carving blades a long time.

Thanks for your input.

Tom

Do NOT mistake me for any kind of "expert".

( ?° ?? ?°)


24 Trina 310 watt modules, SMA SunnyBoy 7.7 KW Grid Tie inverter.

I thought that they were angels, but much to my surprise, We climbed aboard their starship and headed for the skies

Offline oztules

  • Forum Advisors
  • Hero Member
  • ****
  • Posts: 1177
  • Karma: +105/-8
  • Village idiot
Re: Blade station templates for "otherpower" style blades?
« Reply #20 on: May 19, 2012, 05:18:47 pm »
Tom,
All my 4 meter sets have been from sub 8x2 hacked from substandard radiata pine.

The strength is no problem.... if you don't try to make the root fancy.

For mine, I left the first 16 inches solid 8x2 (dressed a bit smaller), and did not try to make the root a next to zero thickness on the windward side.

I did the 3 degrees to 6 degrees half way and just ran the line straight. This leaves a huge amount of wood in the root area. Some folks try to bend the line down to virtually touch the bottom of the root area. Looks sexy, but means nothing of substance.

Leaving the line straight makes cutting easier as well, as there are no tight curves for the blade to follow. The electric chainsaws probably make an easier job of compound curves, as they are generally thinner.... but there is no tangable reason to make it fancy.

Niall, Imsmooth etc, all make much nicer more accurate blades than me I'm sure, but I doubt they could measure the difference in the real world, and Flux is of like opinion..... so I'm happy to agree with him.

You know mine have seen over 5kw, at fairly high rpm, and made from crappy pine, they still survived without a problem.

For your blades I feel 5" at the tip  down to 8" at 16" out from the butt at the root will be simple and good. 3 deg to 6 deg at center point, and extrapolate to the 16" mark at the butt, will make a sturdy set of blades.... simple to mark out, the jig will be simply straight lines, and easy to cut with your chosen weapon.

Cheap wood will likely suffice. I would not spend money on the timber unnecessarily. My blades cost about 35 dollars for the three. 10 bucks for each plank of pine hacked out of the log.... and they were rubbish, but still easily strong enough..... check the knots out on this set. still fine years later.
1171-0

You simply don't need 10 inch timber at all... no useful purpose will be served turning it into planer shavings. The real power is the last 1/3 of the blade. 6 inch would work as well, but strength may come into it earlier, so better grade of timber if you go too skinny at the root.


The trick to carving blades is.......... just do it. It will all turn out ok in the end.

And if your desperate for chainsaw exercise, you can always hack your own planks out of your own logs like we did here:
1172-1

Then the timber is free and so are the blades (except for fuel and bar lube).


....................oztules
Flinders Island...... Australia

Offline DanB

  • Newbie
  • *
  • Posts: 2
  • Karma: +2/-0
Re: Blade station templates for "otherpower" style blades?
« Reply #21 on: May 20, 2012, 06:46:23 pm »
Tom ~ I can give you the dimensions for the blades you had...
or, there is a new blade which does not seem terribly correct in my mind, but designed by TodH from Bergey for this machine which seems to work well (probably better) and it's easier to carve.
Or, if you'll have me... maybe I can just bring you a set and help you w/the project.

Offline Watt

  • Sr. Member
  • ****
  • Posts: 261
  • Karma: +11/-1
  • Over qualified in the inexperience department!
Re: Blade station templates for "otherpower" style blades?
« Reply #22 on: May 20, 2012, 10:56:00 pm »
Tom ~ I can give you the dimensions for the blades you had...
or, there is a new blade which does not seem terribly correct in my mind, but designed by TodH from Bergey for this machine which seems to work well (probably better) and it's easier to carve.
Or, if you'll have me... maybe I can just bring you a set and help you w/the project.

That's a very nice gesture Dan.   ;)
CEO of this Dis-Organization....

Offline ChrisOlson

  • Hero Member
  • *****
  • Posts: 510
  • Karma: +29/-5
  • just trying to survive
Re: Blade station templates for "otherpower" style blades?
« Reply #23 on: May 21, 2012, 01:20:28 am »
Wondering if I can just carve it from a 2X8 (7.25" wide) rather than a 2X10 (9.25" wide) if it will work well enough?

It will work fine made of 2 x 8's.  I'm carving this set out of pine 2 x 8's (standing alongside a GOE222 6.5 foot blade for comparison):

1179-0

The roots on these blades are 7" wide with 11 degree pitch.  The tips are 3" wide with 2 degree pitch:

1180-1

I'm using a NACA 4412 profile

1181-2

I cut them to the taper I want, draw a line on the trailing edge side for the twist I want, then rough them out with a hand power planer:

1182-3

The belt sander does the final shaping and I get out the mic and check them to make sure I got the proper fatness in the airfoil.  Then finish them with the orbital sander and by hand.  The knots are no big deal.  Any holes or imperfections I fix with BondoGlass or BondoHair.  If I got a bad knot I rout it out and fill it with BondoGlass.

The blades in the photo are for a 11.5 foot (3.5 meter) rotor.  They only weigh 3.7 lbs per blade with no sealer or paint on them.
--
Chris

Offline tomw

  • Not as bad as you might think
  • Senior Moderator
  • Hero Member
  • *******
  • Posts: 739
  • Karma: +35/-0
  • hoplophobic people will fear my lifestyle
    • Zubbly's photos!
Re: Blade station templates for "otherpower" style blades?
« Reply #24 on: May 21, 2012, 07:48:02 am »
Tom ~ I can give you the dimensions for the blades you had...
or, there is a new blade which does not seem terribly correct in my mind, but designed by TodH from Bergey for this machine which seems to work well (probably better) and it's easier to carve.
Or, if you'll have me... maybe I can just bring you a set and help you w/the project.

Dan;

Generous offer but I have to decline.

I have a bunch of members here helping me figure out a set and I will follow that course.

If you want to post the dimensions I am sure others will find them useful.

Even better, maybe you can share your experience with the blades you tested from Royal Fabrication? Some of us are going in a different direction than the simply scaled up designs you have been using.  Chain drives, ferrite magnets and different blade designs. All information is welcome.

Thanks for offering.

Tom
Do NOT mistake me for any kind of "expert".

( ?° ?? ?°)


24 Trina 310 watt modules, SMA SunnyBoy 7.7 KW Grid Tie inverter.

I thought that they were angels, but much to my surprise, We climbed aboard their starship and headed for the skies

Offline luv2weld

  • Newbie
  • *
  • Posts: 17
  • Karma: +0/-0
  • No Personal Text Set by User
Re: Blade station templates for "otherpower" style blades?
« Reply #25 on: May 21, 2012, 08:38:25 am »
Tom,
Sorry it took so long to get the instructions put together. I finally gave up on taking pictures and used drawings instead.
I hope this explains how to set up the jigs. If it is still confusing, let me know, so I can fix it.

http://www.anotherpower.com/board/index.php/topic,523.0.html

Ralph
The best way to "kill time" is to work it to death!

I wouldn't need to manage my anger if people would learn to manage their stupidity!!

Offline ChrisOlson

  • Hero Member
  • *****
  • Posts: 510
  • Karma: +29/-5
  • just trying to survive
Re: Blade station templates for "otherpower" style blades?
« Reply #26 on: May 21, 2012, 08:51:37 am »
Tom, I really think if you started carving a blade out of a 2 x 8 you'd find it's not that hard.  The NACA airfoils are really easy because the windward side of the blades is flat.  The other side is 12-15% of the chord for thickness at the hump.  After rough shaping with a hand power planer a belt sander with 40 grit rips it down pretty fast, but not so fast that it takes too much off in one swipe and screws it up.

Even if you do screw one up, it's no big deal.  Go get another $3.60 board and start over and use the first one for kindling in the wood stove    :)

I'm also in the process of trying to figure out how to build a jig to carve blades with a router.  I have this vision of a bed with clamps that holds a blade blank and a sled that runs on a set of rails on each side of the blade.  The sled has a carrier on it to hold a router with rails on the carrier bent to the shape of the airfoil so as the router is moved back and forth over the blank it travels in the shape of the airfoil and carves the blade.

I'm thinking that 100 bucks worth of steel and two 12-packs of Bud Lite, and I should be able to figure it out.  I'm using one of these hand carved blades as a pattern to try to figure out the shape of the rails, etc..  Once I get this outfit built I'm hoping I can whip out a 6 foot blade in 2-3 hours.
--
Chris

Offline tomw

  • Not as bad as you might think
  • Senior Moderator
  • Hero Member
  • *******
  • Posts: 739
  • Karma: +35/-0
  • hoplophobic people will fear my lifestyle
    • Zubbly's photos!
Prophetic??
« Reply #27 on: May 21, 2012, 09:55:48 am »
Thanks for all the replies from everyone.

Hopefully this is not prophetic but there was a vulture perched on the tower for the 12 footer this AM  :o



Full size version here:

http://pics.ww.com/d/449882-1/100_5126.JPG

Click the linked photo to expand it for detail.

Tom
Do NOT mistake me for any kind of "expert".

( ?° ?? ?°)


24 Trina 310 watt modules, SMA SunnyBoy 7.7 KW Grid Tie inverter.

I thought that they were angels, but much to my surprise, We climbed aboard their starship and headed for the skies

Offline oztules

  • Forum Advisors
  • Hero Member
  • ****
  • Posts: 1177
  • Karma: +105/-8
  • Village idiot
Re: Blade station templates for "otherpower" style blades?
« Reply #28 on: May 21, 2012, 06:15:34 pm »
"I'm also in the process of trying to figure out how to build a jig to carve blades with a router.  I have this vision of a bed with clamps that holds a blade blank and a sled that runs on a set of rails on each side of the blade.  The sled has a carrier on it to hold a router with rails on the carrier bent to the shape of the airfoil so as the router is moved back and forth over the blank it travels in the shape of the airfoil and carves the blade."

Exactly the same as the chain saw jig. Should only cost a few 3x1's.

I would still use the chainsaw for the bulk removal, and the router for the finishing. Router is too slow for bulk removal, and too messy. The chainsaw using the top of the blade to throw the detritus away from you is the ticket I think. ... good vision and no mess on yourself.

The router would take the place of the planer and most sanding.... except for the leading edge.



................oztules
Flinders Island...... Australia

Offline ChrisOlson

  • Hero Member
  • *****
  • Posts: 510
  • Karma: +29/-5
  • just trying to survive
Re: Blade station templates for "otherpower" style blades?
« Reply #29 on: May 21, 2012, 08:49:26 pm »
I built the basic stand for it today:

1183-0

It will hold a 8 foot blank, plus I got 360 degree access around the entire area being carved.  I put enough iron in the thing, and wide legs, so it don't move when working on a blade  The beam under the blade blank is a piece of 1/2" wall tubing, and so are the upright pieces.  Now all I have to do is build the rail attachment that holds the router.
--
Chris