Right wing - top surface prep

With the top spar cap complete, it was now time to prep the top surface of the wing for its top skin layup. There is a lot of work to do here....


I removed the peel ply from the top spar cap. I was very pleased the way it turned out. Very flush with the surface, probably due to the weights I placed on top of the spar cap during cure (see previous post).

This however, did not turn out too well. The jury-rigged dam that was supposed to prevent spill off, didn't do such a great job. But that's ok, a little sanding will take care of that...

Time to trim the ends... inboard root...

Outboard end...

And just like that... I was now in Florida. I'll skip the boring details of the move. Luckily, everything went smooth. No damage to anything and a few months later, I was back working on the project.

Next step was to remove the fish-tail on the trailing edge.

I took a knife and trimmed away...

Not bad for a rough trim...

I then switched from knife to manual sanding...

Oooooooooo.... smooooooooooth....

I then took the dremel and cleaned up the micro lines. I always do this with the dremel instead of sanding... otherwise, I end up removing more foam than I should and get a dip.

I then switched my attention to the trailing edge. Recall that I did not put peel ply on the trailing edge (intentionally) - after my experience with the canard, I did not want to repeat the same nightmare where the peel ply gets stuck to the fiberglass.

So in order to get a nice glass-to-glass bond on the trailing edge, I purchased a dremel sanding wheel that did a wonderful job at sanding off the foam and micro... using a slow dremel setting, being gentle on the cured glass.

I made a "check-tool" out of a popsicle stick to make sure I had at least 0.5" of trailing edge for the glass-to-glass bond... note here how it shows I need to trim more foam...



Dremel wheel in action removing the foam...

Time to clean up that shear web face...



A little bit of sanding and all was well...



I then focused on laying out the rudder conduit. I will note that I am going to build the high-performance rudders with internal belhorns. The placement of the conduit on the root of the wing is the same as the original plans; however, the outboard end differs. Lets, take a look:

Here is the inboard root... I'm making the 4.8" mark as indicated in the plans...

Since I will be installing internal belhorns, the outboard end gets placed 1.25" from the trailing edge..



The third spline point is located about 2" forward of the aileron hinge line... on the outboard edge of the aileron...

I placed the 0.025 wall 3/16 OD nylaflow tubing where I made the marks and held it with clamps...

I then traced out the path for the conduit...

Following the internal belhorn rudder plans, the last few inches need to be parallel with the trailing edge...

For the inboard tip, I followed the original plans.. it states to ramp the last 8" such that it is about 0.7" deep at the very end... so I measured about 8" out to gauge when to begin the ramp...

I got my dremel ready...

And milled the conduit channel away...

I was very careful towards the outboard tip to not bottom out into the bottom skin...

I removed the inboard insert...

And drilled a hole through...

This will allow me to slide the nylaflow conduit through...

See...

There it is....



I then cut a channel on top of the insert plug so that I could place it back into its place...

Good fit!





I used tape to mask off the nylaflow and the hole.. this will prevent the micro from running off and bonding the insert back to the wing...

I then put the insert plug back in and taped off the exposed nylaflow tube to protect it from any epoxy droppings..

The rest of the conduit laid nice and flat...

The outboard tip was a bit of a pain.. I simply used clamps to hold it in place until it was time to do the layup...

But before we can do any layups... the top spar cap needed to be cleaned up a bit.. notice the peel ply strings on the edges...

After those were sanded off... I used the dremel to clean up any cured micro runoff from when I bonded all the wing foam sections together...

The wing attach pocket gets a floxed corner the same way the bottom skin had... I also used a metal file to make sure the flox will bond to the glass pocket perimeter...

It was at this point that I wanted to double-check twist and jig alignment.. so I reinstalled the top halves of the jigs...

Here I am checking that all jigs are within 1 tenth of a degree. I agree that an iphone is not a calibrated instrument.. I would however argue that its hysteresis performance is pretty phenomenal! This was easy to test.. I simply placed my iphone on a clean surface... picked the iphone up and placed it back on the surface... I did this about 20 times and got the same exact answer every time. This lets me disregard its magnitude, but made sure all jigs were perfectly level with respect to each other...

Here is a pic showing how I had to shim a few jigs to get them level... and taped the shims onto the table to prevent them from sliding around...

I then noticed a little bit of light shinning through between the wing and the bottom jig.. so I placed weights (unopened epoxy cans) on top of the wing.. and the light went away...

So I used a little bondo to hold the wing onto the jigs... this allowed me to remove the weights and the wing was still held onto the jigs where it needed to be with no light shinning through the airfoil profile...

The last hurdle before moving on to glassing the top surface was installing the nav antenna. I purchased a high-gain antenna from ACS.. the problem now was how to orient the antenna... it came with pretty good documentation showing how the angle of the antenna affects its receiving strength...  so I angled it such that it will be as close to perpendicular with the airflow...

The documentation also states that the antenna must be placed 18" away from anything metal.. so then I questioned "hmmmm, does that include the antenna cable itself?!"

I called up the antenna manufacturer and they suggested I run a bench test to make sure...

So here I am in my hangar... I placed the antenna onto a foam surface...

I used my truck to power my friend's 12V comm/nav radio....

Luckily, I have a VOR on my field at KPIE. But before conducting the test, I needed to know what radial my hangar is located on. So I took a screenshot with my iphone and used digital calipers to measure the orange and red line of the triangle below... with the orange line measuring 49.42 mm and the red line measuring 35.25 mm... simple trig tells us the angle between the orange and purple lines is 35.5 degrees. So my hangar is on the 35.5 degree radial...

And guess what the nav radio showed.... 36 degree bearing... spot on!!! I played with the RG-400 cable a bit and did notice some interference when the cable is run back to the tip of the antenna. So I will make sure to keep the cable away from the antenna as much as possible...




I then placed the antenna onto the wing surface and traced it out with a marker...

Using the dremel, I milled out the area so that the antenna would lay perfectly flush with the rest of the surface...

The antenna is so thin you can barely notice I milled anything out at all..

I then removed the pocket where the BNC connection goes...

Look at that... soooooo flush!!!!

Ok, now for the cable routing... remember my antenna bench test taught me to keep the cable as far away from the antenna as possible.. so I brought it as far forward, and ran it inboard along the leading edge...

I milled out a channel for the cable and pressed it in..

I could have used micro to bond the cable in just before glassing the top skin, but I figured that would be very messy given how the channel is running along the leading edge. Instead, I opted to fill it in with pour-foam...

After a few minutes, it cured and I sanded everything smooth...

To be honest, I'm not really sure how I will route the BNC cable later on. I have the option to either run it along the leading edge of the strakes... or into the center section spar, through the firewall and down the fuselage... that is TBD and will worry about it later...

Moving on... I then made sure the rudder nylaflow conduit was ready to go...

Marked the position of where the peel ply for the attachment points go...

Taped off the outboard end of the rudder conduit to protect it from any epoxy spill off...

This was a lengthy prep!!! But now, all is ready to begin the top skin layup! Stay tuned!