Kitfox Series 7 Super Sport - Show Me Fox

[Jason Murphy]

After consulting with an experienced builder regarding some trouble I had with rigging the flaperon push pull tubes I was able to accomplish the task. It really is amazing how the Kitfox community is willing to help one another. I was clearly over thinking the “neutral” flaperon setting as having zero angle to the fuselage.

I also found another interesting method to hold the wings in place as I work on them. This is courtesy of Rich Kimble who posted a video of his Piggyback STOL kit. I already have my wing jigs all I would need to do is develop a way to support the wing vertically. This could probably be accomplished by placing 2 vertical boards on the jig.

Received my new windscreen, bubble doors, and matching quarter windows also great service and quick turn around by LP Aero.

[Jason Murphy]

Removed the wings from the airplane. Stored the flaperons from the rafters.

Cleaned work area re configured the workspace for working on the wings.

Modified my wing jigs to make a rudimentary rotisserie. There is nothing fancy but it will reliably hold the wings in a horizontal and vertical position to work on.

I will begin work on the left wing because it was already in the work area when it was removed from the fuselage.

I plan on verifying the position of the top false ribs. Prepping the leading edge for the leading edge extrusion and locating and bonding the false ribs.

Simple modification to the wong jigs. I moved my bottom brace where it was flush with the top of the sawhorse. I then took 2x2 and attached it with 2.5” deck screws. I put a small cross bar 16” above the floor to support the weight of the wing. The weight is supported by the lower spar. The top spar can be clamped in place for security or simply float in place supported by the vertical 2x2.

[Jason Murphy]

Moved wing under car port.

Primed leading edge. There were some areas where I broke through the primer Thant I had placed on the spar previously. I also primed some of the cross braces and a few bays of the rear spar with extra primer that I had mixed. This will seal out any moisture and protect the spar in areas you are unable to inspect after the wing assembly is completed.

After the primer had cured I moved the wing back inside and began fitting false ribs beneath the wing tank. I prepped the wing tank with 220 grit sandpaper and bonded the false ribs in place.

I also began fitting spacers below Rib No 2. I am using rib reinforcement material on its side to provide a narrow profile so it will not interfere with aesthetic rib stitching which will be placed there to match the stitching on the other ribs.

Bonded the tail light housing in place on the rudder with hysol. Held housing in place with tape. I plan to return to the area and place a structural fillet after the initial hysol cures.

Filled some voids in the welds on the frame per instructions early in the fuselage build section where the manual directs you to fill any places that may collect moisture with hysol. As I approach covering I need to remember that open access to the airframe will become limited in the near future. I should also look for areas I may need a smooth transition for the fabric.

[Jason Murphy]

Installed false ribs on the bottom side of the left wing today.

Used yard sticks to measure the position of the false ribs on the bottom and then using another set of yard sticks in the front and rear of the rib to ensure the ribs were placed in the same location on top. Measured from the leading and trailing edge of the false rib.

Prior to installing false they were straightened. The edge of a 4” level was used as a straight edge for comparison.

Prepped the spar and stringer with scotch brite and alcohol. Temporarily bonded the false ribs to the spar and stringer. Metal surfaces are re prepped with alcohol and hysol fillets were applied to all of the false ribs.

Remaining hysol was used to fill rivet heads to prevent any potential water from seeping into the wing spar through a rivet head. Also contained to fill areas on the frame where water could collect or the powder coating could potentially be thin.

[Jason Murphy]

Scuffed the primer on the leading edge with 400 grit sandpaper being ensuring Indo not break through the primer.

Prepped the leading edge with 100 grit sandpaper

Dry fit the leading edge with the leading edge template. Provided relief cuts for the front lift strut bracket and any rivets from the spar insert which were interfering with the fit of the leading edge and spar. Dressed up rough edges with 100 grit sandpaper. Cleaned surfaces with alcohol.

Created a hinge from masking tape per the build manual. Cradled the leading edge with side clamp clecos. Double checked the position of the leading edge material. Prepped all bonding surfaces with alcohol. Mixed 65 grams of hysol and applied a bead to the three surfaces which contact the spar. Flipped the leading edge on the masking tape hinge. Rechecked the position of the leading edge at each rib and secured the leading edge with tape.

Using excess hysol bonded the tail light housing to the rudder. I was not satisfied with the result and removed it again and cleaned the hysol off it. I emailed Brandon and promptly received a return email. I suspect that the ribs of my speedster tail may be slightly off which is causing my troubles. I have tried flipping the housing over without improvement. I may need to do some fitting to ensure I do not have any cant. Brandon advised he prefers to install the housing after the covering has been applied.

I took my AeroLED lights outside and used a set of test leads to connect them to the 12v battery of our minivan. It was pretty fun to see them working. Noted the vent hole on my Suntail was occluded. Emailed AeroLED to see if this will be a functional issue which needs addressed.

[bbs428]

Making good headway Jason. Keep on, keeping on!

[Jason Murphy]

Scuffed the outside of the leading edge material with 400 grit sandpaper.

Applied a coat of superfil by wiping it on with a popsicle stick then spreading it with a bondo squeegee. Attempted to create a transition between the ribs and leading edge. Made an initial coat between the wing tank and leading edge. This transition will require at least one or two more coats. Also made a smoother transition around the lift strut bracket.

Marked 4 inch intervals on the wing tank. Used my 4 foot level to bridge between the No 1 and No 3 ribs. Sanded rib reinforcement material down to match the contour of the adjacent ribs. Bonded strips to wing tank and No 2 rib with hysol.

Again using a yard stick to help assess the orientation of the tail light housing. Using the vertical tube the hinges of the rudder are welded. I placed a yard stick on the flat surface of the tail light housing. I measured just above the housing it was 462 mm from the back of the vertical rudder tube. I then measured about 18 inches above the tail light housing and found it measured 495 mm. I checked orientation of the housing and it definitely did not fit flipped over. I then sanded the top of the housing until the distance measured at the two points was 462 mm. (I will attach a photo when I have someone to take the photo because both hands are used to hold the yardsticks.

Called Kitfox about exchanging firewall for a burnished firewall. I wish I knew about this option when I ordered my FWF kit. It would need to be shipped freight which may be cost prohibitive especially both ways. Exploring options I could have it powder coated. I looked at round trip flights. I may be able to fly up for the kitfox fly in and check the firewall as cargo and fly it back. I would need to call the airlines for more information.

[Jason Murphy]

I am hoping this will be a with while investment of my time especially since I did not choose the Laker Leading Edge option.

My plan for tomorrow will be to work my way down the wing with my 3/8” rod and sand a nice smooth radius into the fillet of Hysol used to bond the ribs to the spar. I will be stopping just short of the spar and this will allow the Hysol to serve as a warning that the spar is just below that point if I continue to sand.

After sanding the radius I will lay a bead of Superfil behind the line that is tangent to where the fabric will take off of the wing. After the bead cures it will act as a dam and I will fill in front of the bead to ensure a uniform and smooth transition of the fabric off the spar onto the ribs.

Otherwise I could simply fill the small triangle area in front of the ribs and see how that makes the transition. I setup a handful of ribs in this fashion towards the tip of the wing to attempt this method. We will do some sanding in the morning and decide which method works best.

[Jason Murphy]

Mixed up Superfil, applied round 3 to left wing. Suspended left wing from ceiling.

Moved right wing to wing jigs. Scuffed epoxy primer on leading edge with 400 grit sandpaper.

Using heat gun removed the false ribs to straighten them and place them back onto wing. Used towels to insulate and mask areas I do not want to heat such as brackets. Setup shop vac to blow cool air down the wing spar to prevent heat from being conducted to areas I do not want to be heated. Monitored the temperature of areas I do not want to heat by physically touching them to ensure they do not become hot. Cleaned up old hysol with scotch brite.

Tomorrow I plan on cleaning up the ribs with a dremel and remove all of the old hysol. I also need to finish cleaning up the old hysol off the spars.

I would like to bond the leading edge and the false then apply the superfil and begin creating a transition between the leading edge and ribs with Superfil.

I am wondering if I should fill the areas on the bottom of the fuselage between the landing gear attachment points and between the forward landing gear attachment point and the fabric attachment point just rear of the boot cowl.

[alexM]

I am wondering if I should fill the areas on the bottom of the fuselage between the landing gear attachment points and between the forward landing gear attachment point and the fabric attachment point just rear of the boot cowl.

My opinion (worth $0.002), yes. I did, and if I built another Kitfox I would also fill the space between the main gear attach point and the brackets behind them.
PXL_20230321_234651864(1).jpg