NACA-0014 Rudder Modification Underway

[Greene]

Instead of a hardwood leading edge you could just add 2 or 3 layers of matting in that area.  It would give you some extra stiffness and impact protection.  That is what I am going to do with my third rudder upgrade. 

As far as adhesive choices you can use the epoxy or just buy a tube of styrofoam adhesive at a hardware store.

Mike

[ssullivan]

any one still have templates?

[DougN]

I found the templates on-line and printed them out.I can't remember the site but if I found them it couldn't have been too hard.I read and reread all the posts on this subject before
I started.I used Bob's suggestion and moved the leading edge forward.Everyone seemed concerned about the strength of the leading and trailing edges so I made the framework out of aluminum.With my background I'm more comfortable working in metal but that's just a personal preference,I used 3/16 rivets because I don't trust my welds on old aluminum.I found a site were they tested trailing-edge profiles and mine match their ideal perfectly,just dumb luck on my part.A good tip was to drill a hole in the  bottom of the blade then drive ln a nail to help hold and rotate during fabrication.Worked great but I drilled and tapped for 1/4x20 bolts instead.Later I used these to fasten a 1/2" aluminum skid-plate as per Skip's suggestion.With the low water levels in the Great Lakes it seemed like a good idea.I've yet to test it as I'm still putting the rest of the boat back together.Good luck....Doug

[Bob23]

Ssullivan:
   I have the templates. If you pm me your address, I can make paper copies and send them to you. I have NACA 0014 with 12", 13" and 14" chords.
Doug:
   Pretty cool idea working in metal. Probably the same reason I made mine of wood- that's what I work best in. Mine is ready for a recoat of epoxy before she goes to work this season.
Bob23

[Ted]

Well, it's time for me to get started on my rudder mod.

I have an extra used CP19 rudder blade. The blade is bit pockmarked so I have to clean it up a bit first.

Where are you getting the templates? I am interested in making a 0012. I loaded up the java app on http://darwin.wcupa.edu/webapps/javafoil/ and it does put out a design but I am not sure what to do with that. Do I just size it up to fit and I am good to go?

[curtisv]

Doug, Mike, Bob,

I've just reread this thread (for better or worse) to try to figure out if there was any consensus on whether the NACA 0012 or the NACA 0014 was better and where to get the pattern.

I noticed that online there is a NACA 0012-34 and a NACA 0012-64.  Both have maximum thickness of 12% at 40% back from the leading edge.  The -34 has a sharper leading and trailing edge.

Which one have people been using for rudders?  I think the NACA 0014 is the same except scaled so the maximum thickness is 14%.

A good URL for patterns is http://www.airfoiltools.com/airfoil/details?airfoil=naca001264-il.  With this you can make your own patterns

This is a set of coordinates for plotting NACA 0012-34:

  0.000000  0.000000
  0.012500  0.011330
  0.025000  0.016800
  0.050000  0.024930
  0.075000  0.031330
  0.100000  0.036530
  0.150000  0.044930
  0.200000  0.050930
  0.300000  0.058000
  0.400000  0.060000
  0.500000  0.058270
  0.600000  0.053200
  0.700000  0.044800
  0.800000  0.033200
  0.900000  0.018670
  0.950000  0.010270
  1.000000  0.001200

This is NACA 0012-64:

  0.000000  0.000000
  0.012500  0.018130
  0.025000  0.024530
  0.050000  0.032670
  0.075000  0.038130
  0.100000  0.042400
  0.150000  0.048670
  0.200000  0.052930
  0.300000  0.058270
  0.400000  0.060000
  0.500000  0.058270
  0.600000  0.053200
  0.700000  0.044800
  0.800000  0.033200
  0.900000  0.018670
  0.950000  0.010270
  1.000000  0.001200

The above sets of numbers give the curve for a 1/2 section (where 1.00 is the back end).  Multiply the second column by 7/6 should yield a NACA 0014.  Multiply both columns be 14 if you want a blade width or 14" and then convert to fractions (round to 1/16 or 1/32).

Here is a rendering of NACA 0012-34 plugging in the numbers into xfig and doing a cyclic interpolated spline.



Has anyone put more rudder area forward of the original aluminum blade?  The IDA, for example, is a more balanced rudder in addition to being a foiled rudder.  A balanced rudder has enough area forward of the rudder pintel vertical pivot line to counteract the force applied to the tiller by the area that is aft of that vertical pivot line.  That is one of the reasons that the IDA doesn't not fight so hard to bring the rudder back to center.  Both my original flat blade and the IDA are 12" wide.  I take it that is the reason why 2" is added at the front (besides impact damage) in the 14" wide rudders.

Curtis

[Bob23]

Curt:
   With respect to adding rudder area forward of the original blade, I have added about 2" when I made my wood foil. Of course I have nothing to compare it with, but the foiled rudder works great. Of course my reason for adding forward area was to combat that dreaded 23 weather helm. If I had the time, I'd make a bunch of different interchangable foam prototype blades that I could slide over a stock aluminum blade to test for comparison.
   Bob23

[curtisv]

Bob,

Thanks for the reply.  IDA is 12" wide with the whole thing pushed forward 12".  Seems the DIY solution is to go with 14" and overlap the blade with 2" forward.  I have the IDA and it works well.  A just for comparison temporary rudder swap at a future BBB would be interesting.  If I build one I can do my own rudder swap (and see if I can notice any difference).  Since I already have a 12" 0012, maybe I'll build a 14" 0014.

Anyone know if IDA is using the NACA 0012-34 or the NACA 0012-64 template?  I have two pairs of rusty vernier calipers, so I could clean them up and take a look see.  Anyone know exactly which NACA 0012 or NACA 0014 (ie: the -34 or the -64 for NACA 0012) they used, or is these all the mysterious Doug142 template?  Apparently the Doug142 works quite well so for those that built them why worry about exactly which pattern it was.

Curtis

[GeeW]

I am spooling myself up for having a bash at modifying our C16 rudder, and was wondering what weight (and how many layers) of glass you chaps are using on the foam foiled rudders?

Gordon
C-16/3 #2767 'Applejack'

[DougN]

Gordon,if you search the archives on this site you can find everything you need to know.Not having a clue how to get started,I simply followed the advice and instructions everyone here generously shared.If I could remember exactly what I used I'd simply post it(it was a while back).It was a fun project.You won't regret it........DougN

[Greene]

I used a single layer of glass on my first rudder and found it to be too easily dinged.  The next couple I used two layers which worked perfectly.  

Mike

[H2operator]

Here's a few photos of my CP- 23 rudder project...

[H2operator]

More....

[H2operator]

More.... I'll post a few more photos as I make progress, Lance

[Bob23]

  Very nice Lance and very similar to mine. Wish I could find the links to my build...and that I could remember how to post photos here. I sheathed mine in 4mm (I think) Okoume  plywood that I purchased from Chesapeake Light Craft. It was expensive- I still have over half a sheet left!
  What a difference in made in the boats handling and pointing. And, it's pretty to look at!
Bob23