K8 recovering

[Steve P]

Similar to your second photo. Flat on racks with much closer spacing is my approach...

[blake]

Steve,

Thanks for the photo.
Can you tell me how you made the rack?
Is it just wooden dowels or metals rods that support the wings?

Blake

[Steve P]

Blake -- there are two 2x4 running on the flat with a dowel every few inches. All done on a drill press so that all the holes are precise and the dowels align straight and level. That rack is on its second workshop and is over 20 years old. I have two others, 1/2 the size over workbenches.

[mogman]

Adjustable shelving from Home Depot and some foam pipe insulation.

Cheers,
Dave.

[blake]

Ok guys, the saga continues.....

I've finally had some time to get back to work on the K8.
I have finished applying the sheeting to the forward portion of the fuselage so I will have to sand it to conform with the existing "stringers" so that it will still look like an open fabric style fuselage.
The cockpit area is still being worked on and the massaging of the new open style cockpit will continue when I start sanding the fuselage sheeting.

The main focus is now the wings and the installation of a proper spar system into the pre-built panels. A series of carbon rods and additional shear webs are being added to each of the four wing panels. I have started on the inner panels and am working on the installation of new the rear spars first. The photos show how I removed some of the sheeting to gain access to the spar/rib joints so I could drill the holes for the carbon rods. I used my 90 degree angle drill with a pilot drill, then worked up to a size just slightly larger than the carbon rods.



First panel with some of the sheeting removed to help with drilling the holes for the carbon rods.



Drilling the pilot holes for the new spar caps(carbon rods)



Holes drilled in the ribs for the rods.

Rod being inserted along the back of the rear spar in the new holes.



View showing the upper and lower caps in place.

Onto the shear webs next.

New shear webs being sized. I used rock hard 3/16 balsa here for the rear spar. Front spar will have plywood shear webs and larger diameter carbon rods.

The new shear webs being fit before gluing.

Notice I made some stands to hold the wing upright and to not induce any twist into the structure.

That's it for tonight.

Blake

[blake]

Sorry,

Here is a shot of the forward part of the fuse all sheeted, ready for sanding/contouring. Then it will be ready for glassing and paint.
If you noticed that the fuselage is rather short for a 6m span....the previous owner Steve R, did a cool mod and made the fuselage two parts....super easy to transport!

[ARUP]

Or you could 'mod' it and make it a flying wing kind of contraption!
To what is that right angle drill attachment attached... a Dremel? How do you like it?

[blake]

The 90 degree drill is actually a 90 degree drill, not an attachment.
Like this unit....

And I love it, comes in very handy on these larger sailplanes.

[blake]

Ok,

So moving onto the main spar re-enforcement I discovered something really shocking and downright scary actually!
If you look at the photos you can see the little shear web doubler part number G4C, well "Mr.Wood" forgot to apply glue to this rather important part! It popped out in my hands when I was trying to trim it's edges for the new carbon spar caps. I mean there was NO glue at all holding this part in place.

Makes me shudder to think about all of the other Phoenix K8s flying around like this. So glad I decided to rip this thing apart and do a proper spar system.



When I was trying to trim it's edge for the carbon rods it popped right out!
There isn't too much in there for such a large sailplane. Definitely lacking in proper design practices!




I installed the new carbon rod spar caps and will be adding 1/4" Liteply shear webs next.



Oh, and I picked up a new compressor for the shop, replacing the tiny one I was using before.
You can see the little guy peaking out from behind the new one.
For some strange reason I can't get this photo to upload in the vertical position....LOL! Maybe Len can fix it for me...?



So the work continues.......


Blake

[ARUP]

That angle drill is noyce! Great catch on the shear webs! Did you buy a lottery ticket, too? Who is the manufacturer/distributor of this bird? Noyce compressor. I need to run a 220 so I can get one like that. Waiting for smaller ones to refill gets tiresome.

[blake]

Here are some shots of the front spar getting the carbon rods and plywood shear webs.
I had to cut open the D cell sheeting in front of the spar to gain access so I can install the required carbon rods there as well.



Opened up D cell to allow access to front of spar.
If you notice, I only had to open up a bit of the D cell as the new spar caps in this area only project approx. 25" from the root.



1/4" dia. carbon rods caps and plywood shear webs installed.



Lots of load carrying ability in this area now!
Just have to install the two carbon rods in front of the spar now, then tie in the wing rod tubes to the spars. Will probably copy TomP and his use of epoxy and heavy cloth for that purpose.

Continuing on......

[blake]

Ok

Spar caps located in the D cell are now installed. Again , one upper and one lower.
I then glassed 3 of the 4 receiver tubes.
Then I moved on to the tip panel and installed carbon caps same way as the main panel.
After talking with the engineer about the need for additional caps in the tip panels we both decided that they were needed after all, so in they went.
By doing this we have "chased " the weak link right out to an area that sees very little dynamic loading.
We also decided to go to a solid carbon tip joiner and not the hollow tubes that come with the kit.
After all that work was completed I re-installed all the sheeting that I removed to gain access to all the affected areas.
I wanted to add lower spoilers as well, so I got some off RCG for a good price. I had to build a spoiler box to house the actual spoiler, and a frame in the wing to take the tension from the covering material.

Opened up the D cell to add the required sparcaps on the front of the spar.

Fibreglassed the receiver tubes.

Tip panel with new sparcaps and shearwebs.

Detail of the tip panel with the sparcaps and shearwebs.



New box for lower spoiler.


Frame for the spoiler box.


New spoiler box installed with temporary height spacers.

So all this wing needs to be complete is a good sanding, then ready for covering.
On to the port wing now.

All of this work added 0.800kgs/1.76lbs to the righthand wing. Lefthand should hopefully work out about the same.
Not bad really, for all of the added material....

More to come.

Blake

[ARUP]

Nice strength and conditioning work there!

[Tom]

Looking good....where did you source the solid carbon joiners for the outer panels from?

[blake]

Thanks Michael, if only I looked as strong and in shape...LOL!


Tom,

The large diameter solid carbon rods for the wingtip joiners came from CST in California as I couldn't find a supplier in Canada that carried the correct dia. The smaller diameter rods for the spar caps came from a local Canadian supplier. CST nailed me for shipping, buggers......don't think I will be getting things sent across the boarder if I order from them again.

Tom, I have been looking at the root/canopy fairing area like you suggested, and have drawn out the line that would match what the actual full scale airplane has for a junction. I'm afraid that if I remove the material needed, it's going to go right through the sheeting, and there is no access from inside to add more material. Any thoughts?

.
The work continues....

Blake

[Tom]

Thanks for the info on the carbon rods......I'll look into it. As far as the root/canopy area goes....my plan was to just remove the sheeting from the area and build it back up correctly. Start with the span between the root ribs and sheet that from the leading edge back up to where you will have cut the old out.......once that is done you can add the canopy fairing over the top of that. Hope that makes sense.....

[Tom]

This is how I will do mine.......