Foam Ribs on Pilot Side and Conduit

This morning we cut the wing ribs with our segmented hotwire.  It worked great.  We had a little manual shaping to do with a sanding bar, but it all worked out very well. 

You may notice the white tube in the leading edge foam.  This is a conduit for stobe and Nav light wiring if we decide to add it later.  It is PVC pipe, but it is very light and has an extreemly thin sidewall.  The total weight of a 4 ft section is only 2.6 oz!  The total weight added to the plane is less than 10.4 oz!

The root rib is at -1 degree, and the tip is -1.56 degrees.  The extra few degrees at the tip causes the tips to stall last. That should make the plane not want to drop a wing when it stalls.

Wing Spar Extentions and Ribs

Between 10/7/2010 and 10/24/2010 we added the following Foam wing spar extentions. 

They are standard foam with KR Glass on both sides overlapping the spar by a few inches. We then trimmed out the edges and filled them with Flox. I was amazed at how stong they are!


You may notice the problem with image. The filler we used was Micro, Not Flox! We were able to easily peel out the Micro and redo with Flox.


 
 
 
 
Durring the weekend of 10/24/2010 we glued foam between the spars and on the front and the back for the wing ribs.  We also finished our templates for each end.  We are going to hotwire all the ribs in one pass of the segmented hotwire we built a few weeks back.
 

 
 
 
 

Hotwire issues

I was trying to devise the best way to cut the foam wing ribs for the KR.  There are 5 ribs in the outer wing.  The wing both tapers to a shorter chord at the tip, and changes airfoils completly!  I attempted to plot out the airfoil at each of the 5 locations but had less than perfect results.

After much time was spent working with a spreadsheet and CAD, I decided to see if I could do a hybrid of methods to acheive the wing ribs. 

On the origional KR, The foam was glued in place and a large strait edge sander was used over 2 templates to shape the foam.  This has a few downfalls:

1) Sanding is messy
2) The foam you would have to use is OPEN cell foam.  It requires a coat of micro to seal the cells
3) The foam is not available to me localy so I would have to drive 5 hours, or have some very large pieces of it shipped.

I decided on trying to use the standard Polystyreen foam and a long hotwire.  Unfortunatly, the hot wire would have to be so long that I was sure I did not have a way to power it.  I wondered if I could Segment the wire by making the electricity "Jump" across parts of the hotwire by adding a larger wire in some segments giving the electricty a path with a lot less resistance.

Here is our attempt using our long bow and a 14 gauge wire with aligator clips:



As you can see, It worked..  So, it was time to make a looong bow that could span all 5 wing ribs on the outer spars which as 90" long.

Here is the final product:



Now I just have to hurry and finish the foam spar extensions before it gets to cold to fiberglass!  I hope to have wing ribs in place and shaped by Halloween!

Aileron cables completed!

Over the past few nights I have managed to finish the aileron cables.  They don't move as smooth as I would like.  I suspect there is a pivot point not moving smoothly. I will be looking into the problem tomorrow

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Elevator cable routing preparation

This week I was able to cut the rear horizontal stabilizer to make clearance for the bottom elevator cable and glued in an extra wedge for the bolts to bolt against. we also drilled and tapped one end of the elevator push rod.

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It's official. It's 8 ft wide....

This past weekend we reviewed what we would like to do next and decided to glue in the Horizontal Stabilizer so we can finish the Elevator controls next weekend.  The tail is 8ft wide rather than the 6 ft wide the plans calls for, so it's not very trailer-able and will barely fit through any garage door now.  We could not do much since we did not want to disturb the plane while the glue was drying, so we did not get much done.  We did a little cleanup and worked on a 23cc Weed Whacker engine I had laying around in hopes of using it for a giant scale model airplane engine.

It's Been a while.....

As usual, I'm a bit behind in blogging.  It's been a summer of painting, sanding, filling, sanding, filling, sanding, filling.

The Horizontal Stabilizer has had several coats of filler on it and sanded many times.  When the airport is so far away, it's difficult to make the 25 min drive each way for a 10 minute session of sanding and adding a coat.  A word of advice for other builders would be to keep it at home as long as possible.  I'm considering moving it back home once the wings are completed and can be removed so the plane fits easily in the 2 car garage.

The other things we have been working on are the controls and the seat.  I've found that there is a lot of making a part 2, 3 or even 4 times.  This summer we created our second seat with some help from Ken Jones.  He had some left over fiberglass that was terrific for the seat.  It was very heavy and one layer on each side can support my weight as I enter and exit the plane.  We will need to load test it to 3G's  (2 people at 200 lbs each, *3 = 1200 lbs of static load!)   I think it may need one more layer, but it's going to work out.

After the seat was ready, it was time to work on the first control surface.  The Rudder.  The Rudder pedals have been completed for a while and were installed.  They now have cables attached and move the rudders.  I have tested them by putting all the force my legs can push on each pedal and nothing has failed.  I would like my welds to look more professional, but I'm confident they will work.

I have been concentrating on learning things that will make me more efficient in ordering materials and in planning.  I have been  learning DeltaCad after seeing the many drawings my dad has made for the airplane.  I did not understand how he made some of the drawings and while I trusted my dad, I wanted to understand.  As much as I appreciate his help, I want to know I could do it if he wasn't there.

With that in mind, I loaded DeltaCad's free 30 day trial and ran through the tutorials.  I have since drawn my kitchen floor, my hanger, and 1/5th scale wing ribs from the AS5048 Airfoil Coordinates. If you're interest in learning a very easy to use 2D cad program, check out http://www.deltacad.com .   There is a 30 day free trial, after which it costs $40.  The tutorial will walk you through everything you need to know.

We Went to "SloshKosh" 2010 and I was personally very disappointed.  It really should have been canceled.  The only good things I got out of it was spending some time with my dad, and getting started learning to Gas weld with Oxy-Acetylene.  I have always heard how difficult it is but I was surprised that I did not find it that difficult.  I may be able to make my own custom length engine mount after all.