Kitfox-4 floorboard or firewall options for access

[rogerh12]

Howdy all;

I started to install my floorboards today in my model 4 when I realized it would be held down by the rudder peddle brackets and control column mounts. I think this will be a problem later if I want to remove these components for service as under the floor boards will be fabric (so how do I get to the mounting nuts or inspect the tubs for cracks ???). I was thinking about using metal plates for floorboards instead of the wood as well, maybe make them removable without disturbing the controls, or maybe not run the fabric all the way to the front of the plane, and instead extend the firewall under the plane back to the seat area or something (and make the rear portion of the extended firewall removable with screws.

Any ideas?

Thanks in advance

Roger

[SkyPirate]

I would not replace the wood with steel,..to get the same rigid performance of the wood ,..out of steel would add weight ,.. it would also offset any pre designed heights that were accounted for in the design ,..the wood thickness versus the equivelant for rigidness in steel,..your other suggestion of making a removable plate's makes more sense,..just take into concideration your radiator location if your using the 582 or 912,..and your choice of landing gear as to how you conform the plates,..also the material you choose to make the plates out of and the support system for them

[rogerh12]

The metal in the floorboards would be thinner than the wood, and be made of Aluminum (0.062 aluminum diamond plate is available locally) or perhaps Titanium if I can gets some more cheap. I was thinking the stainless firewall would extend under the fuse, and the removable underbelly portion would be aluminum (a 6061 series or something like that). Oh, this plane is also a Tri-gear, so the nose wheel mounts must be taken in consideration, but the engine will be air-cooled only, so no water radiator will be required.

[HighWing]

I agree with your concern. It was after I built my first model IV that the Service Bulletin came out regarding cracks at the rudder pedal torque tube junctions. I had to remove the rivets securing the bottom firewall extension to get at the nuts for the torque tube pivots. I am building again and will install the aft edge of the firewall part to the floorboard like the radiator is mounted with a two or three through bolts. For the stick torque tube, by far the easiest way to make the nuts accessable would be to add some inspection rings to the fabric and then when necessary cut the fabric and replace with inspection covers. I put an inspection ring on the left side only as the pivot bolt in the right side is accessable.
Lowell

[enyaw]

Could you drill the tab holes larger and install rivnuts? We did this for our bagage compartment.

[Geowitz]

I just put inspection rings and left them uncut so if I do ever need to get to the nuts it will be easy. As Lowell mentioned you really only need access to the left side since you can then remove the tube once that side is removed. Also, as Lowell said you can mount the bottom section of the firewall with through bolts or some type of screw to make it removable to get to the rudder torque tubes.

[FoxDB]

Hello
On my model 1 following fuselage mods for my new landing gear prior to recovering I used these clip nuts http://www.aircraftspruce.com/catalo...es/0402052.php
to hold on the stick tube brackets. This allows control and floorboard removal with no fabric problems. They are lock nuts so no concern with loosening.
Dave

[rogerh12]

Some really great ideas here, thanks for the pic of the underbelly, that helps me visualize the setup.
Anyone got a picture of the underbelly with the firewall installed??

The rivet nuts are interesting, but I wonder if they will hold up as well as actual fiber nuts, and I am not sure about the ease of removal later. The clip nuts I have used before, but I have also had the move on me and fall off during bolt insertion. I like the inspection holes perhaps best and the picture gives me something to work toward.

[Esser]

Depending on how you were finishing your plane I dont the checkerboard aluminum would weight more than the wood with carpet on top. Just a thought.

[SkyPirate]

the 1/8" tread plate aluminum / bright ,..which is grade 3003 aluminum is very workable ,.and it's reasonably priced,..the advantages of 3003 ,..it is the same material used for making fuel tanks so it doesnt stain easily,..it is easily welded ,..scratches, if not too deep can be buffed out too.
The only problem with it,..if your going to use the tread tape on areas where your heals go,..you might have to use a heat gun to get it to stick down to the surface due to the "tread" design in the aluminum ,..you could get the spray on rubber for this instead,..and now I believe you can get it in different colors ,..if not ,.the spray on tread that comes in the quart can that has to be reduced (which is a yellowish color )is paintable.
if you use aluminum instead of the wood ,..put something between the aluminum and the airframe where the aluminum would meet the 4130,..tape or split hose on the tubes spaced about 2 inches apart,.. the reason for this ,..vibration will wear the coating off /primer/baked enamel/?/of the 4130,.2 unlike metals rubbing on each other will cause oxidation/corosion,..dont forget to make spacers the same thickness as what ever you use to seperate the 2 metals where there are any thru connect points.

PS . if the aluminum proves to be too reflective ,..if you wash it with an aluminum cleaner it will take the shine off and leave it a light gray in color ,..remove it from the plane first ,..the cleaner is acid based