Winglet Intersection Fairings

This is the completion of the winglet fairings for now. I still have the ends to do and I have an idea for that. I’m also unhappy with the thickness of the fairing. Its not a big deal but would need me to do several full days work to correct. Its not worth it for now. I’ll see how much it bothers me in a few months and next time the wings are off. Structurally its really strong being a touch thick. Correcting it would probably be no less drag. Its just optics and I want to keep going with the build.

I had some decisions to make as to how wide these fairings would be and where the curve would begin and end.

My trusty set of french curves helped and I made it ‘pleasing to the eye’. Too big and its just more wetted area for more drag. Too small and I’d ask why did I bother? I cut the ends in line with the rudder which worked out nicely.

I checked for interference and made some small adjustments.

The close out is quite neat.

I did a flox corner on the inside curve which you can see above with some peel ply. The other issue I’m addressing is that the bottom of the winglet is just slightly wider than the rudder. My fix is to add a few plies of BID to the inside of the lower winglet and then I’ll sand the outside a bit to fix the problem, knowing that there is enough ‘meat’ left. Its one of those things thats been on my mind to sort out and now is the time to get it done.

Here we are all sanded back, the darker areas is where I’m into the glass. I’m just doing a little filler to tidy up the outer area too.

It is now acceptable. Not perfect but quite OK.

I’ve also lightly trimmed the TE of the rudder to a perfect fit in the winglet. It just needed about .05″ at the top. Probably close to the gap that the hinge required after I’d cut the rudders out. Its all in line now.

While I was doing all this rudder work, I revisited the tip light fit. Don’t be too alarmed at the amount of filler. When I made the wings I put an indent for the light into the glass and foam so I could do exactly what you see above. This way I could bury a little of the light’s foot print without diminishing its function. In other words that 0.15″ or so of useless ‘light base’ I’ve sunken away.

Here it is with a good fit all the way around.

These lower winglet fairings have to be done with the wing inverted. Given I need to do the fill on the undersides it was time for the wings to yet again come off.

I’ve been allowed to borrow some Cessna 182R stands which they use when doing the undercarriage maintenance. They were just a bit short so I had to spend a few hours making extensions out of some scrap laminated timber I had left over from doing the CS Spar Jig.

A team of five people got the wings off. I still don’t have the knack on this one. There were also a couple of stands and boxes around that got me inverted wings without damaging the winglet tops. The blue foam is to protect them from my attempts to kick the perfect wing tips.

Here’s what we have after doing the top fairing. That metal came off easily.

I’m down to the bottom of my pour foam tins. One side I had to do the whole thing twice as it remained rubbery for some reason. This side cured OK.

Looks better after a good sand.

Here’s the other side.

This is after three plies of BID. Possibly overkill? I am thinking if the plane ever goes backwards I want a strong area here.

Its going to look great trimmed to the correct length. I’ll do that when the wing is right side up and maybe with the rudder on so it all looks correct when I do the cuts. Patience I tell myself.

This mod was inspired by James Redmon’s excellent testing of the concept. I’d also been looking at this for some years firstly when doing speed mods to my flying plane.

This is an oil flow of my wing where you can clearly see the separation at the trailing edge.

Back on the ground and its clear something, lets say, not ideal is happening here. So thats why I’m going for a fairing in this area.

First up I put the plane in cruise angle mode. I’m predicting 2 degrees nose up at 180knots+   Did I mention it was 38C in the hangar today with no breeze, given the doors were shut. Yes I REALLY want to finish this plane.

I was also worried it may tip backwards so the baggage pod box came in handy.

Finding the highest point on the wing chord that is level proved to be trickier than I thought. The glass there is very uneven so more eyeball engineering went into play.

Eventually I found some place to put a line I could live with. The Berkut winglet is certainly a little different to the Long-EZ. I worked to a compromise of what I know of drag from a few books, some formulas and more of that eyeball stuff.

All this was just so I could put a couple of plies of BID on the rudder in prep for the pour foam fairing shape to come.