Kitfox Series 7 Super Sport - Show Me Fox

[Jason Murphy]

Received a call from the DPE, CFI-I check ride will be rescheduled he accidentally double booked himself. I decided to take a break and work on the plane instead. Multi Engine training begins next Thursday.

Prior to starting I spoke with another builder who has the Hoerner Style wing tip seeking advice or lessons learned while they had fitted their wingtip. I was advised to fit the wingtips before covering. Clamp straight edges to the wing to assist in alignment. Trim only the top first. Drill some temporary holes and cleco in place. If needed these holes can be patched later. After getting the top just right clamp and mark the bottom. Trim up the bottom rinse and repeat. It will take several fitting sessions to get things right. Then turn your focus to the trailing edge. Using a straight edge mark and trim.

Dry fit wing tip onto right wing using clamps. Noted interference of the forward spar tube with the wing tip. Used an 8 ft level as a straight edge placed across the top of the wing ribs. It appears I will need to compensate for a slight droop.

Dressed up the end of the spar tube to eliminate interference. Dry fit wingtip using clamps again. I am starting to get the feeling this will be another exceptionally tedious task if I am going to make this look right.

Following the advice received earlier in the day I will need to trim the topside first. I am thinking I could layout a pattern on the aluminum strip and drill No 40 pilot holes. After I get things trimmed, sanded, and fit I can use my angle drill attachment to back drill / match drill the wingtip from the inside. This would ensure I have proper edge margin on the aluminum. I would then bring the holes up to full size.

I am also wondering if the wingtip would benefit from using a countersunk washer and countersunk flat head screw to hold it in place. I believe the pressure would be better distributed but this may require a slightly wider aluminum strip to serve as the wingtip attachment point. I am open to feedback and suggestions.

Pictures to follow or click the link

https://eaabuilderslog.org/?s=ShowMeFox

[Jason Murphy]

Tried emailing the pictures to myself and attaching them via web browser today. They are JPG images... No Joy

[Jason Murphy]

Used an 8? level across the cap strips of the ribs to help me determine the wingtip is flush with the wing.

Used a 4? level across the leading edge. Brought the wingtip flush with each straight edge. Clamped wingtip in place. Using the outboard edge of the No 10 cap strips I measured 5 mm from the cap strip which was actually the largest deviation from the cap strip. I then connected all the dots using a ruler and a reinforced cut off wheel made a rough cut and snuck up on my cut line with sandpaper. I now have a much straighter edge. I am going to repeat the process on the bottom edge and start making plans for final fitting.

I have the photo feature quasi working, it seems to only allow attachment of one picture. Regardless the photo that is attached is a faring on a PC12. I would like to know if anyone has used countersunk washers with flat head screws to attach the wingtip. I eyeballed the thickness of a washer and I wonder if it is thicker than the fiberglass. I also believe I would need to have wider attachment strips to allow adequate edge margins on the mounting strip and wingtip. The photo appears to be a No 8 screw and there is approximately 5/8 to 3/4? center to edge distance.

IMG_1433.jpg

[jrevens]

... I would like to know if anyone has used countersunk washers with flat head screws to attach the wingtip...

I did... #8 SS screws and SS washers. I epoxied the washers to the fiberglass.