Kitfox IV modifications

[109JB]

I may be able to get a Kitfox IV project close by where I live. It is uncovered and I wanted to get a list of modifications that you guys that have been flying Kitfoxes and Avids for a while have made and feel are worthwhile. I'm interested in hearing about all modifications, but especially those that are considered mandatory and need to be done before covering. Don't think that any mod is too trivial or simple because I want to try to think of all and incorporate the ones I want during the build rather than try to add on later. I'll start the list below. If you would when you post let me know if you think a particular mod is mandatory, nice to have, etc. Just so you know some of the parameters, the airplane will be a tailwheel airplane powered by an 80 hp Rotax 912. I'm going for light weight as much as possible.


Modifications List


1. Comply with all Kitfox service bulletins and service letters


2. Reinforce fuselage sides where landing gear mounts


3. Reinforce landing gear truss where bungees attach


4. Different main landing gear (Grove, cabane type, other) (I'll probably go with cabane type gear)


5. Larger pneumatic tailwheel (Probably a 8" Matco)


6. In flight adjustable elevator trim tab. (Electric or manual)

[Dusty]

The Murl williams wide body kit would be a good starter as the 4 is a bit cozy. Also remount the top harness position directly on your centreline as the single mount in the middle lets the inner strap slide off and the outer chafes. Unfortunatly even small modifications add up in weight. However a heavy (730 ib)4 with 80 hp still performs extremely well.:D

[jrthomas]

If you plan on mounting your comm antenna on the plate behind the turtle deck, it would be a good time before covering to figure out some kind of ground plane. Also my model 4 has a 2nd plate a couple of feet back toward the tail that would be perfect for your ELT antenna except that it's about impossible to install after the fabric is on. I ended up putting my ELT antenna on the inside. And be sure to put an inspection cover beside the tailwheel leaf spring bolt. I had a leaf spring break while flying a friends model 2 (a single leaf). It was easy to replace with inspection cover. Would have been a bear in the field without. I'm sure I'll think of something I wish I had done.

[109JB]

Thanks. Good suggestions. Here is the current list. Again, likely won't do all of these, but will consider any suggestions.

1. Comply with all Kitfox service bulletins and service letters
2. Reinforce fuselage sides where landing gear mounts
3. Reinforce landing gear truss where bungees attach
4. Different main landing gear (Grove, cabane type, other) (I'll probably go with cabane type gear)
5. Larger pneumatic tailwheel (Probably a 8" Matco)
6. In flight adjustable elevator trim tab. (Electric or manual)
7. Beef up tailspring mount area.
8. Inspection ring near tailwheel spiring bolts
9. Ground plane for antenna mount
10. Widen fuselage at seat back (Murle Williams kit or other)
11. Relocate shoulder harness mount so that straps don't fall off shoulders.

[rogerh12]

To that list, I would like to add:

A Center Floor console to route your wires through, and add position adjustment notches on the flap lever
Find a place to mount a fire extinguisher, this probably means welding in a plate somewhere
Replace wood floor boards with metal
Add cargo bag, and possible add second cargo area behind bag for light weight things, such as pillows, sleeping bag
Add close outs between the floor board and seat pan to keep stuff from rolling under the seat and jamming the controls
Add weldment to attach rudder trim tab - hand bending type.
Make sure you use the metal header tank with low level sensor
consider boost electric pump on the header tank outlet, and make sure you can drain the tank.
Leave empty space on your instrument panel for tablets or other devices used in navigation
Use hand held communication radio to save big bucks over installation and maintenance/certification of panel mounted units
Add blocks to bottom of seat pan in case the straps break, so you don't jam the controls under the seat

Hope this helps
Roger

[Av8r3400]

Yup. You guys are looking for The Mangy Fox... I have every one of those mods except the "widening" kit. With the bubble doors, it really does nothing for space in the cabin.

23985

[napierm]

I have the grove gear. Are there some good pictures showing the reinforcement of the side frame around those mounts?

Thanks

[Av8r3400]

This is how I modified my IV-1200 Classic.

24961

[jrthomas]

VG's, bubble acrylic doors and 22 Dessers. The Grove gear is a tremendous improvement over the original bungy gear. Desser also makes 27 and a half inch tires but for my type flying from paved and grass strips the 22's work great for me.

[napierm]

Thanks! Is that 1/16" 4130?

Also, roger12, why the metal header? My kit has the plastic one that goes under the right seat. I see the metal one in the KF catalog but not sure why they changed it out.

[rogerh12]

Thanks! Is that 1/16" 4130?

Also, roger12, why the metal header? My kit has the plastic one that goes under the right seat. I see the metal one in the KF catalog but not sure why they changed it out.


Well all the plastic ones seem to leak after awhile, a short while in some cases. The ones that are blown molded, and not fiberglass or aluminum tanks.
Hope this helps
Roger