Kitfox Series 7 Super Sport - Show Me Fox

[Jason Murphy]

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.
Attachment 32489

Thanks Alex, the image you attached shows exactly what I was trying to visualize. It appears to be a very smooth and clean transition that you created. I will very likely follow suit.

[Jason Murphy]

Used dremel to remove hysol from false ribs which have been removed. Emailed Kitfox asking for prices on replacement ribs thinking they could not be too expensive and it may be a more efficient use of time. They wanted nearly 10 dollars each. I sent Brandon a picture and he reported the old ones were serviceable. I plan to check into the military standard it is my understanding the adhesive used to bond the ply is not adversely effected by heat. Otherwise I could easily go to Wicks and purchase some 3 mm Finnish Birch Ply and use my unused ribs as a master template. The cost to do this would be around 40 dollars in materials. I have 2 friends who are accomplished wood workers and I'm sure would be happy to let me use their shop.

Onto forward progress. I cleaned up all the remaining hysol from the spars with scotch brite.

I created relief cuts in the leading edge material for the rivets on the spar and the lift strut attachment bracket. I prepped the bonding surfaces of the leading edge material with 100 grit sandpaper and alcohol.

Took a break from building to teach a local ambulance district how to use the new ventilators they received from COVID grants. Then back to building…

The leading edge template was used to locate the leading edge material on the forward spar. Once again a hinge was created from masking tape per the instructions. The bonding surfaces are once again prepped with alcohol. 80 grams of hysol was mixed and used to bond the leading edge material to the front spar. Masking tape was used to secure the material and the position of the leading edge material was once again checked using the leading edge template. A fillet of hysol was used to bond and fill the areas relief cuts were made. Cleaned excess hysol with alcohol and set to cure for the night. After excess hysol was cleaned from relief cut for lift strut bracket tape was used to secure leading edge material approximately every 2 to 3 inches.

[Jason Murphy]

Note: Previous post occurred on 19 June 2023

After adhesive has cured rechecked the location of the leading edge.

Mixed 180 g of Superfil and applied to the leading edge to create a smooth transition between the leading edge material, the spar, and wing ribs. I will need to return and create transitions between the false ribs after they have been replaced. I spent some time cleaning hysol from the ribs which had been removed. I have about half of them completed at this time.

[Jason Murphy]

Day at work spent planning my next workday and developing a shopping list for my next trip to Wicks or to place an online order with Aircraft Spruce.

Called Garmin because I am having trouble finding hardware which will work to secure the pitot mast in the adjustable Garmin mount. The problem I am experiencing is a No 6 screw is loose and a No 8 screw will not fit. Before modifying the kit I wanted to check with Garmin and see what hardware they recommend. The lady who took the call was unable to provide any additional information. The suggestion was made to ream the holes to accept a no 8 screw. I am less than enthusiastic about that plan although it may be the only option. I would like to find AN hardware similar to a bold that has an unthreaded shank to provide the most support. I will continue to follow up on this.

While shopping I noticed cable lacing tape was made from Waxed Dacron and had a tensile strength of 50 lbs. I emailed Poly Fiber and ask if their flat rib lacing cord would also be suitable for this application. Greg at Poly Fiber confirmed their Rib Lacing Cord is also made from Dacron has a similar tensile strength and would likely be suitable for that application as well. So rather than use Black Cable Lacing Cord I will use my Poly Fiber Rib Lacing Cord for double duty as Cable Lacing Tape as well.

Over the past few days I have continued to dwell on what my registration number will be. I was not fully satisfied with my previous choices which I had reserved. I developed various combinations of my children’s birthdays and queried the FAA database for the various combinations. I finally came up with a registration number I am really happy with N462SM. It used the last digit from each of my children’s birthdays followed by SM which stands for “Show Me” because the airplane was built in Missouri and Missouri is the “Show Me State”I paid the fee and reserved the new N Number today. that I am really happy with.

Watched some videos on covering with Poly Fiber. I am interested in the Superflite process as it was highly recommended by me friend Roy.

Emailed Kitfox regarding my filler neck on the wing tanks and the best way to clean that up and prevent corrosion. If there was any reason I should not use body filler on the fuselage at the landing gear attachment points and if I would be able to have powder coating applied to various parts without damaging them.

I plan to begin the Aircraft Registration process tomorrow and continue work on the leading edge.

[Jason Murphy]

Sanded initial coat of superfil with sanding block.

Applied second layer of superfil In required areas.

Touched up around the tank filler neck. I will need to apply a generous amount to the top of the wing tank and sand smooth. The curve of the wing tank is not smooth and consistent across the width or depth of the tank. There is a gap of nearly 1/4” in some locations when checked with the leading edge template. Scuff sanded the top of the wing tank in preparation to apply filler. I will likely need to do something similar with the left wing. I plan to use my 4’ level as a sanding block. Otherwise I could pickup a sanding block at Wicks.

[Av8r_Sed]

Hi Jason,
I'm enjoying the detail and thought you're putting into your build thread. Please make all the mistakes before I get to my next build. I did notice in the registration post, that you're pretty much DOXing yourself putting out that much information from the form. Pretty easy for any bot to pick up all your info. I'm not sure if it would work, but taking down that photo and replacing it with a redacted one might be a good move.

[Jason Murphy]

Things are slowly coming together.

Sanded the second coat of Superfil down. I only have a dab left in my tub so I will need to get another tub on the way. That will be my 3rd tub since beginning the project. The wing tank filler neck cleaned up nicely. I will attach a photo to a later entry.

I plan on taking a pencil and marking the spots that I missed last time and applying 3rd round to fill any small bubbles and to continue on streamlining the lift strut bracket.

Comparing kits who used the fiberglass leading edge the edge is trimmed at the lift strut bracket.

I plan on moving the left wing back to the jigs to work on it while the Superfil cures.

[Jason Murphy]

With the help of Ted Myers & Myers Aviation reached a solution to the hardware needed for the pitot tube mast.

increased the size of the hole using a No 19 drill bit. A No 20 bit would allow the threaded portion of the screw through but not the shank.

Used an AN525 Washer Head Screw which was sufficiently long the unthreaded shank was long enough to fit through both ears of the bracket to secure the mast in place.

Need to order some No 8 washers and No 8 AN365 nuts to secure the assembly. I will order 4 - AN 526 6-32 R4 screws to secure the pitot tube in the pitot mast. This satisfies Garmin specifications of 0.218 min - 0.312 max length requirements.

[Jason Murphy]

Additional thoughts regarding hardware for the Pitot Mast… and we wonder why I have trouble sleeping at night.

A fact that I had overlooked yesterday. I chose the heated pitot tube. It would likely be best that I use a metal lock nut because I chose the heated pitot tube. The heat may conduct its way through the mast and weaken a nylon lock nut. There is a comment in the instructions regarding a minimum length the aluminum tube should be before the pitot / AOA tubing transition to plastic.

I will contact Garmin for clarification on the suitability of a wooden board to mount the tube and the requisite for other mounting hardware.

[Jason Murphy]

This entry contains a few days of work.

Ordered some additional avionics today I will be using the Vertical Power System to manage power distribution.

I committed to the decision of fabricating new false ribs. The existing ribs are probably safe however up to this point in the project I have never been shy of doing extra work to give myself peace of mind.

Yesterday I made a trip to Highland IL to Wicks Aircraft. I picked up some hardware, Superfil, Uncertified Light Fabric for use as bias tape and to cut doilies from when I begin the covering process. You may ask yourself why I would make my own bias tape and the reason for that is I am able to start with one thickness and make it wider where the bias tape will make a corner. This would give my finishing tapes a uniform perimeter all the way around otherwise you may run into where your border is 2” then in the area your bias tape is you only have a 1.5” perimeter.

Today I began work on fabricating new false ribs using the plywood purchased from Wicks Aircraft. Referencing the videos published by Kitfox I purchased 2.5mm Finnish Birch. The kitfox ribs measured 0.107” which falls between 2.5mm and 3mm plywood. The 2.5mm ply measured 0.100” and the layers matched the original ribs. I compared them to the 3mm ply wood and it was thicker and the schedule in which the material was different. I concluded the difference may be due to different lots.

Using an original Kitfox rib which I had not bonded or fitted to the spars I traced both the bottom and top ribs onto the material. These two ribs were designated as “master” ribs. They will be saved after the project is complete if I should happen to have the need to make additional ribs. I could have left some additional material between the parts to use as a buffer however I wanted to make sure I was able to cut a whole set of ribs from this one piece of material.

When I contacted Kitfox for replacement ribs, they wanted approximately 10 dollars per rib for replacements.
They also wanted to sell me full sets of 46 and 52 ribs which made the final price just under 1000 dollars for replacement ribs.

I was able to purchase this board for 35 dollars which is enough material to produce a whole set of top and bottom ribs for one wing and extra.