Kitfox Series 7 Super Sport - Show Me Fox

[jiott]

Jason, I like your idea of making your own bias tape and varying the width to suit. Bias tape is wonderful stuff that makes doing corners a piece of cake. However, the width does shrink quite a lot as it is pulled around a corner.

[Jason Murphy]

Using a scroll saw cut new ribs.

Left ribs slightly oversized with the intention of sanding the false ribs down to the profile of the wing ribs.

I made a few extra and have some leftover materials if I need to make a few more.

[Jason Murphy]

I have been lazy the last few days and not particularly focused on the project.

I got back to work for a bit this afternoon. I began the task of creating a nice smooth transition for each rib and removing the excess Superfil.

I was also not satisfied with my No 2 rib on the left side. Using a coping saw I loosened the handle where the blade would flex. I was able to slide the blade between the elevated capstrip and the wing tank and cut the rib stiffener material that held the capstrip in place. I then used an into dremel and widdled away at the adhesive and prepared the surfaces for bonding again.

I have 2 more that I need to clean up before bonding the capstrip again.

I have also developed a new strategy how I will locate supports for the capstrip.

The poly fiber manual states to have rib stitching every 2.5 inches at a minimum within the prop wash area. I intend to use the front and rear of the rear spar as index points and begin my spacing from there. That way I will not be trying to run stitch and have a wing spar mess up my spacing.

If my memory serves me right center to center of the wing spars is 27.5” this means there will be a minimum of 10 to 11 stitches which will lie between the leading edge of the rear spar and the trailing edge of the rear spar.

And then we went fishing

[jiott]

When laying out the spacing for your rib stitching, there are several more things other than spars that can interfere with the spacing, such as the diagonal drag tubes, etc. What I did was to lay out my spacing marks on a thin flexible strip of wood or fiberglass trimming. Then move that stick to each rib and make sure there is nothing in the way under it at each mark. Check each rib on both wings. I found I had to tweak my spacing marks several times before I found a pattern that worked everywhere. If you do this ahead of time your rib stitches will all line up perfectly, instead of having to move one or two out of line to miss something under it. Don't worry if you have to stretch or shorten a spacing 1/8" or even 1/4" different from your normal spacing. That small difference is not noticeable if they all are the same and perfectly lined up.

[Jason Murphy]

When laying out the spacing for your rib stitching, there are several more things other than spars that can interfere with the spacing, such as the diagonal drag tubes, etc. What I did was to lay out my spacing marks on a thin flexible strip of wood or fiberglass trimming. Then move that stick to each rib and make sure there is nothing in the way under it at each mark. Check each rib on both wings. I found I had to tweak my spacing marks several times before I found a pattern that worked everywhere. If you do this ahead of time your rib stitches will all line up perfectly, instead of having to move one or two out of line to miss something under it. Don't worry if you have to stretch or shorten a spacing 1/8" or even 1/4" different from your normal spacing. That small difference is not noticeable if they all are the same and perfectly lined up.

Thanks Jim, I took your suggestion into consideration today.

Referencing the poly fiber manual the area within the propwash area needs to be spaced at maximum of 2.5”

Propwash area is defined as the diameter of the prop plus one rib bay.

The biggest prop I have seen up to this point is 75” meaning 37.5” from the center of the fuselage is the propwash area. By eyeball 20 of those inches is fuselage leaving the tip of the prop to fall somewhere around the second rib. Plus 1 rib means the 3rd rib should have a maximum of 2.5” then for the remaining ribs I will have to work out that spacing.

I do know if I use 2.5” indexed off the rear spar the diagonal tubes will get in the way. I may try shifting my start ot stop point.

To tease out my remaining ribs I think I will use the diagonal tubes as an index and I will measure from the trailing edge to be repeatable when the fabric has been bonded. The remaining ribs would require a maximum of 3.5”

Also on the bottom of the wing my hole spacing will need to be slightly tighter because there is more distance across the top of the wing. When I did the math it came out to 2.45” I rounded to 2 7/16”

Thanks for keeping me from dorking this up down the road!

[Jason Murphy]

Started the day by finishing my cleanup job on my No 2 rib.

Sanded away the old hysol and prepped the tank for bonding again. I believe I failed to mention the reason why I am repeating this work. Despite my best efforts the no 2 rib was quite proud over the surrounding false ribs and wing ribs.

Figured out rib lacing spacing for the underside of the wing. I plan on throwing some stitches under here to continue the pattern and to help the fabric adhere to the under camber. Mixed some Superfil with micro balloons to prevent sag. Applied a dollop of Superfil and laid the rib into place. Double checking its position vertically and laterally on the wing. Placed levels and angle iron on the rib to hold it down. Used popsicle sticks as spacers underneath. Applied a generous amount of hysol mixed with flox to the forward part of the rib. Which will undoubtedly be exquisitely painful to sand and transition.

The remaining portion of the day was spent sanding and creating a nice smooth transition between the ribs and the leading edges and spar. I feel to eliminate this step is the real reason for the composite leading edge.

Applied a small amount of hysol to small air bubbles areas and did some additional work around the lift strut to provide a nice smooth surface for the fabric to bond and take off from.

[jiott]

Personally, I like the look of the same stitch spacing the full length of the wing, even though it is legit to widen the spacing outside the propwash area. All stitches lined up look really good.

[Jason Murphy]

Not much to say today.

Continue dressing the leading edge with sand paper.

Finished making transitions between the wing ribs and the spars and leading edge.

I hope this is not a mistake.

I have noticed there are small dips between the baffles of the wing tank as well as the leading edge of the wing tanks and the trailing edge of the wing tanks.

Sanded the top of the wingtank to give the superfil something to bond to. Cleaned the top of the tank several times with alcohol and lastly acetone to ensure there were no mold release agents which would interfere with bonding.

I applied a skim coat (210g) of Superfil to the top of the wing tank. I am going to visit the local autobody shop and see if I would be able to borrow a large sanding block to create a nice uniform finish across the top of the wing tank.

That seems like a lot of weight but I would be willing to bet that 2/3 of it will be sanded away.

The goal is to create a uniform crown on the wing tank and improve the transition of the No 2 rib at the rear of the wing tank.

Fingers Crossed!

[Jason Murphy]

Sanded superfil from top of wing tanks to a minimum thickness. Checked leading edge using contour gauge and it still needs some work. Crown of tank is level between tank baffles.

Very time consuming but I believe the end result will be worth the effort.

Installed header tank. I was required to dress the upper left bung in order for the bolt to pass. Measured from the cross tube below the tank to the bottom of the tank to make sure it was mounted square. I should probably dress the edges of the other bungs on the wing tank to prevent snagging and minimize sharp corners.

I plan to have the header tank finished with powder coat or primer.

Laid our floorboards, plan to arrange the grain of the wood span wise to better blend the transition between boards

Removed rivets from rudder pedals.

Took rudder pedals and levers to Powder Coat to have color changed from white to black

[Jason Murphy]

Unfortunately I was not able to work much today. I was out all night the evening before as a medivac nurse/medic and needed to sleep most of my day off away.

I have been wanting to remake floorboards for quite some time. I laid the original floor boards out on my 1/8” mahogany ply and traced their shape. Rough cuts were completed using a hand saw. Finer cuts were made using a scroll saw. I plan to reach the final dimensions and fitting with sandpaper. In order to better locate the floor board tab holes I plan to turn a drill guide from scrap aluminum. I will then stain the internal laminate mahogany finish sand and use a spar varnish to seal the wood. It doesn’t make sense to use the epoxy varnish when the floor boards do not need to withstand the abuse of the MEK and will provide a better finish. I recruited the assistance of my oldest son Jaden to assist in cutting the boards.

I have also received some additional tooling I purchased second hand online a coax crimper and stripper.

I have also began to make preparations for AirVenture. I greased the wheel bearings of my camper today. I consulted our base mechanic on his preference for a grease gun and he advised I should buy a Lincoln. I found one online for a comparable price to the local hardware stores and I must say it is a quality piece of equipment. All the tire’s including the spare have been inflated to their recommended pressure. We will be making lists and taking care of odds and ends over the next week.