Initial Fit for Flapperon Hangers- Model 5

[N14ND]

Looking at my builders manual (95) it has the fitting/drilling/installation of the flapperon hangers and flapperons after cover. I have a Model 5 with the original fish-mouth style hinges. Has anyone indexed the hangers and pre-drilled the ribs for the hinges prior to covering? Looking the hole locations of the hangers and the width underneath the cap strip with the aluminum gusset there's not a lot of room for error. The edge distance looks pretty small. Covered in fabric it would seem to make it a high worry item. I thought of a layer of masking tape and a layer of duct tape to simulate the fabric and rib/trailing edge tape thickness. Then do the fitting and pre-drilling of the holes. That way I know the holes are correct.

Thanks.

[Jerrytex]

I too am using the old style. I am mocking up 6 layers of fabric (3 on top and 3 on the bottom) to get the spacing right. I didn't do enough spacing on my KF 4 and it was "fun" getting the brackets on after covering.

[alexM]

Looking at my builders manual (95) it has the fitting/drilling/installation of the flapperon hangers and flapperons after cover. I have a Model 5 with the original fish-mouth style hinges. Has anyone indexed the hangers and pre-drilled the ribs for the hinges prior to covering? Looking the hole locations of the hangers and the width underneath the cap strip with the aluminum gusset there's not a lot of room for error. The edge distance looks pretty small. Covered in fabric it would seem to make it a high worry item. I thought of a layer of masking tape and a layer of duct tape to simulate the fabric and rib/trailing edge tape thickness. Then do the fitting and pre-drilling of the holes. That way I know the holes are correct.

Thanks.

I would swear my series 5 manual (98) discussed pre drilling them. I'll look in my manual tomorrow and see. I agree that the margin for error would be small and doing them ahead seems like a great idea.
I've got all new ribs so I'm going with the new style brackets.

And yes, mocking up the thickness of the fabric as Jerry suggests is very important with those fish mouth brackets.

[N14ND]

I re-read the manual this morning. Oops. You do predrill the hangers before cover. I saw the picture on page 105 of the hanger on after fabric and my brain went flat. Then I read the notes in faded pencil I made years ago. Sorry for the confusion. ;)

[bbs428]

Yes - get them all set correctly and drilled prior to covering. Measure thrice and drill once! Glad you found it.

I re-read the manual and seem to find out something AFTER I muck it up. I force myself to re-read each section prior to that particular step and it's helped reduce the forced errors. Thank goodness most covering mistakes can be corrected with MEK and more Poly-Brush.

I would add that as you cover, you melt thru to the holes with a small soldering iron. Each time you add a tape or over-lap the fabric your holes will disappear and you'll have to fit the corresponding flaperon hinge to find them again. Ask me how I know... :o

[alexM]

I re-read the manual and seem to find out something AFTER I muck it up. I force myself to re-read each section prior to that particular step and it's helped reduce the forced errors. Thank goodness most covering mistakes can be corrected with MEK and more Poly-Brush.

I had one of those moments last night when I was bonding ribs into the vertical stab. Suddenly had the thought that I needed to do them in a specific order.
Thankfully I was okay.
Decided to RTFM before doing the ones with the aluminum angle

[N14ND]

Along the same line... I made guides for the hangers to hold the two halves together with the correct spacing from the upper bolt edge to the trailing edge (1/4"). The issue I have is the one that Jerrytex ran into in regard to getting them to fit post cover. With nothing on the ribs to simulate fabric/glue/edge tapes/UV block/topcoat the hangers fit correct as per the manual. But even the slightest amount of tape will not get the correct fit without deforming the hangers.

So, the question is if the hanger is installed back slightly so it fits without deforming the hanger (the additional distance aft from the manual is an 1/8" when I have the estimated fabric thickness of tape installed) will it make a difference to the flapperon function? I can still get all the rivets in the rib.

I can see why Kitfox went with the longer/beefier hanger that just attaches to the top. Makes installation much easier.

[Jerrytex]

I think as long as they are all the same as far as the distance off the end of the rib, you're ok. It's a happy medium between "deforming" and getting them tight on the rib.

I thought about the new style hangers, but I have seen some pics and I am not sure if they were done correctly but it appears the lower rivets on the brackets come through the bottom of the trailing edge and stick out. Not sure if this is the norm but, I didn't like this look. The older style, to me, seems more "Beefy" but are a PITA to install.

[PapuaPilot]

My hinges were predrilled before I bought up the plane second hand. I think the first builder had them tight without any allowance for fabric. It was a pain to get them on and match the holes.

I would put 2-3 pieces of card stock such as 3x5 cards to simulate the fabric. There is going to be 2-3 layers of fabric on there plus all the under layers and paint.

[N14ND]

I put down one layer of masking tape (to get the duct tape off) and three layers of duct tape. It’s about the correct thickness. I mic’ed my elevator aft tube and it’s about right.