Mike's Kitfox IV rebuild

[4Hummer]

Finally found myself a Kitfox here in Canada. I've been searching a long time, Problem is supply is extremely limited here n Canada, and most in my price range where Model 2's with 2 stroke engine and tons of hours.

This 1993 Model IV (Built and flying in 1995) only had 150 hours on it, and has a Rotax 912 80 HP engine. Aircraft had only 3 owners (2 in the last 3 years) and the build quality was exceptional. Original builder/ owner kept great logs, did lots of maintenance and only flew an average of 15 hours a years in it.

Log book shows he does his annual inspection. puts it on floats, takes it to the cottage, flies it a couple times a month and puts her away for the winter. Rinse and repeat for the first 15 years of her life.

Here is Foxy all loaded up on the custom trailer ready for her new home

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Aircraft happens to match the wife's pickup truck to boot

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Amazingly it fits in my 2 1/2 garage. Which means I get to spend the winter tweaking and making changes

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[4Hummer]

Shot of the Trailer. Very well built and thought out.

The drive home (2 hours) was a little nerve wrecking, high winds meant I had to keep my speed down to 90 KM/h, and the darn passenger door kept popping open. We drained the tanks completely, and built the transport bars for the wings, Other than some tense moments on the drive my Kitfox arrived home safe and sound.

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[4Hummer]

Day one was spent stripping, cleaning and inspecting everything.

Engine is good, needs motor mounts (the rubbers) and ignition cables, One of the scat tubes for carb heat needs to be replaced.

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Floors all cleaned up, Will need to clean up some wiring and fuel lines. Battery is shot and WAY to small, will order a the 680. and am going to replace the battery cables. And the old 121.5 ELT does in fact work, previous owner thought it was shot, new battery and its up and running.

Header tank needs to come out at some point to have a bung welded in for a low fuel warning light/buzzer

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Wiring is nice and tidy, but it will be all ripped out and done my way. (I don't believe in using the frame for grounds)

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Dash is also a Redo for me

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[4Hummer]

Lots of elbow grease, and the seat covers came out good as new.

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Spent today moving the fuel shut off valve from below the throttle to the foot well, I'm 6'4" and found the factory location impossible with my long legs, It's still easily reachable but now no longer jammed into my knee.

The yellowish tinge you see on the fuel line is some clear tubing to protect the fuel line from rubbing. I also redid some of the fuel lines to run perfectly straight (Did I mention I have major OCD?)


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[4Hummer]

Tomorrow the Windshield comes off. It has a major crack that was "Fixed" with zip ties and RTV. (Hey it held...so good temp fix for sure)

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Due to my size (Tall not fat) I'm going to order the bubble doors in Medium Tint, I'm trying to source some 0.093 Tinted Polycarbonate here in Canada for the windshield. The Acrylic windshield is over $1100.00 Canadian with shipping and handling, and I've read too many horror stories of people cracking there new acrylic windshield. Bubbles doors I'll just have to swallow the cost and exchange rate ($1783 Canadian for the 2 doors, install kit and shipping, plus there will be duty on top of that)

Anyone have a source for Tinted Lexan in Canada ? Found a few places online in the USA but shipping is always $300+ for $100 sheet.

[Dusty]

Very nice
btw the 80 hp doesn't need a very big battery, I am running a motobatt MBTX 12U. It is more than big enough.
I like your location for the fuel cock. I may copy that

[4Hummer]

Started replacing the wiring today.

All new power and ground cables will be going to a central bus bar.

Replacing the main power lines from the battery with some nice WindyNation 4 AWG Silicone wire. Great wire (Overkill yeah maybe) Solid copper strands (not tinned) #4 battery and welding wire. Very flexible !

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Side by side with the original 15 + year old wire, some of the protective sheaths is starting to come off the original stuff and is corroded aluminum wire.

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Will be replace all the wires to the starter and engine ground as well

[bbs428]

Following along. Beautiful Series IV. Glad to see it being restored to a flight worthy status.
Aluminum wire and corroded to boot. Wow. Bet your happy to see all that hit the trash can! I like welding wire as well - copper and very flexible. :)
I still have a lot of tinned wire that's left over from my yacht repair business so its being "repurposed" So many electrical problems I solved back in the day due to faulty grounds. Salt water didn't help... ;)

[4Hummer]

Parts are starting to arrive and get installed into the aircraft

Power and ground distribution blocks installed. The Large "lugs" in the foreground to the right is Power (red) and Ground (black) in from the battery, these are toggled via the master switch and relay located near the battery.

The wires leading threw the fire wall go to the starter relay +, and engine block -


The distribution block (aft and left) are the bus bars: one for central ground - (the rearmost), and Power + which will be wired from the ACC via the Key switch (Not connected at this time)

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Wires from battery and relay. Green will go to "Master Switch" (Battery still needs to be replaced, so the battery box cover is not yet on, nor is the battery strapped in)
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[4Hummer]

Once my Cleco's arrive I will be tackling the windshield

Smoke grey tinted lexan .118 (Hoping with some heat and carefully forming I can get this to install and NOT crack) I couldn't find tinted lexan here in Canada at any thinner thickness (I know your suppose to use .060 or 0.93)

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Anyone have a template for the wing root cutout or tips. I don't want to use my old windshield as a template since is was a bit of a hack job.

[Jfquebec]

Maybe you can made a paper template over the old one🤔

[t j]

Anyone have a template for the wing root cutout or tips. I don't want to use my old windshield as a template since is was a bit of a hack job.

I took these measurements off a windshield I built for my Classic 4 kitfox. The new windshields come with the pattern roughly outlined about an inch or so outside the final fit.

[4Hummer]

Thank you.

[4Hummer]

Banged this out quickly,

Both headphone jacks and USB charge port, located behind the passenger seat (Easy access for the pilot)

Can't take credit for the idea, as I saw it on this forum first and thought to myself "Genius Idea" I always hated jacks in the dash, with wires everywhere.

Nothing is wire up yet, But I did temporarily connected the the USB port just to see it light up and say "Oooooh Awwwww"

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[bbs428]

I also saw this on another post but just the headset jacks. USB port is a natural in the same location. Brilliant! :D

[4Hummer]

Not a whole lot to report. Drafted out the new dash.

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Tested out in cardboard. have to make some adjustments, unhappy I have to put the Airspeed indicator in the lower left side of the dash, but all the other steam gauges are just to long, and the ASI is the shortest

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Lots of new wire runs for.....well everything

[4Hummer]

oddly satisfying removing the door skins.



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Naked !

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Anyone need some door skins ?

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[4Hummer]

I seem to have less and less aircraft as time progresses.


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[4Hummer]

Two 1N5400 Diodes arrived in the mail so I installed them on the starter and battery coils.

Heres my way of connecting them: Remember the stripe on the diode goes towards the positive side. I used clear shrink wrap over the assembly.

Connected to the main battery coil
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Close up of the shrink wrap and ring terminal's, Sized so the diode can never be installed backwards
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Also some of my circuit breakers have arrived, maybe soon I can start wiring things up.

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[Dusty]

I'm intrigued as to the purpose of the the diode?

[4Hummer]

I'm intrigued as to the purpose of the the diode?

"The diode acts as a surge absorber or one way gate. Anytime you turn the power off an inductive load (coil, motor, solenoid, etc) the collapse of the magnetic field creates a voltage spike of opposite polarity to the voltage applied"

Basically it prevents arcing on the key and or toggle switche(s), The inside of the relays use a magnetic field to open the contacts, when turned off, this magnetic fields collapses and creates a massive reverse spike in power (Often many times greater than the forward voltage) The diode is basically a one way valve for power.

If you've ever seen burned or melted contacts on the key or toggle switch, it because a diode wasn't used. The reverse spike can often times fry sensitive equipment.

For the $3.00 it costs to install it's a worthwhile precaution to take

[Hawkertech]

Most of the Corporate jets I worked on had diodes on the back of all the switches.

[jrevens]

Any time you have an electromagnetic coil (pretty much any relay or "solenoid" relay) it is good practice to use a diode - usually at the coil as shown by Mike. Sometimes it may be more convenient to locate them at the switch(es), but is usually done at the relay or contactor on our aircraft. As he said, this is to protect the switch contacts controlling that relay from the momentary reverse voltage spike when the magnetic field collapses. That can create a pretty good arc which can be very hard on contacts.

[Dusty]

Thanks, I have learnt something today.

[4Hummer]

Does this madness ever end ? =) All these wires will eventually be cleaned up.

Everything is numbered with network cabling tape. (Previous life) I really like this tape, sticks like crazy (Almost like hockey tape or skin tape) numbers don't wear off easily, oil and gas resistant and cheap. I number things in Groups. 30's Radio, 20's: Ignition, 1-19 Accessories kinda a thing

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On my 999th template it feels like. Couple more adjustments and it should be good for CNC. Carbon fibre background with white lettering will be the end result:

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need a tad bit more space for the circuit breakers.

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[4Hummer]

And guys! The shielding wire DOESN'T get used in the circuit, it instead gets it's own independent ground (On one end only) the design of the shield is to shunt all RF noise back to ground so it is not picked up by the radio,

Here's an example for the Mic and Headset wires, Green wires are soldered onto the shield and connected to a separate ground.

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The independent radio ground, all the shielding gets connected here and than goes back to the central ground buss.
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[4Hummer]

Grips. From Meh! to Niiiice



Originals

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Now

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[4Hummer]

1" Heat Shrink tubing over the control stick.
Spank Shorty Grips (they are like the lizard grip's that are so popular)
LED PPT. with 3D Printed adapter

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Powered up to test.
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The 3D printed adapter can be found here:
https://www.thingiverse.com/thing:3783281

However he sells the entire kit cheaper than I could find JUST the buttons. Comes with wiring guide, printed instructions, connectors, plus fast shipping, and lots of colour choices
https://www.ebay.com/itm/153736492549?ul_noapp=true


Only tip I have when covering the stick with the heat shrink tubing is do the centre of the stick first, than work your way out each end, you will need to pull the wrinkles out at the bends and shrink, pull a little more, shrink, pull shrink.

[DesertFox4]

Very nice work. 👍

[4Hummer]

Another mile stone accomplished. Windshield cut and fit

I have been putting off installing the windshield for weeks now. It honestly wasn't all that hard but pretty time consuming. Traced out the outline of the old windshield and added about an 1 1/2 on all sides, than started measuring and trimming. Original windshield was installed cock eyed, and was way off.. (thank goodness I added extra material and was able to compensate) also glad I didn't reuse his original holes.

I can see now why the old windshield cracked he had the whole thing off centre by quite a bit, and forced it straight by the window pillows, I noticed his error when I was measuring to cut out around the wing spar, things just didn't line up left to right.

Rounded all the edges and sanded smooth, I now have a love hate relationship with clecos must have had this lexan off 15+ times to adjust and trim,


This is .118 Smoked Grey Lexan (Only lexan in tinted colours I could find here in Canada) It's a little thicker than recommend but seems to be working very well so for. Purchased from Polymershapes Distribution Canada I dealt with Roberto: rfernandez@polymershapes.com Cost was $145.00 Canadian for a 48 x 96 inch sheet with $35 Shipping to my door.


Original rough cut and layout

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Spar cutout.

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Close up. I than rounded and fitted, and rounded and fitted. repeating until perfect

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Almost final fit. will install the windshield with Riv Nuts instead of rivets.
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Turtle deck is next, Just need to purchase the proper Rivets.

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[bbs428]

That's some nice work on your new windscreen. The light smoke imho is just the right amount of tint. Looks perfect!

[4Hummer]

Rudder Peddle Reinforcement Kit.

Thanks Kitfox... this sure makes it easy.
Still have to glue in the sleeves and paint the brackets, Just test fitting here and showing you all the complete kit (M1-C4) from the factory.






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[4Hummer]

Under Seat Storage installed.

Had to repair some of the previous "repairs" prior to final installation (The very dark brown fibreglass wasn't me) and fix some other cracks in the seat pan.

I think every Kitfox should have these storage boxes installed or at least some sort of butt blocker, seeing the shape this seat pan was in, one hard landing or opps and you loose some of your flight controls, It's great insurance, and adds a handy storage area.

Bottom View:

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Top View:

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Test Fit with scrap lexan lid (Old windshield), Final version of the lid will be done with leftover tinted lexan from the windshield

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[4Hummer]

Time for the wheels.

Nanco N800 21 x 12 x 8 on the right.

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Mounted: Thankfully they round out a bit. was a bit worried when they arrived

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Unfortunately I cannot install the tires, Seems the past few owners have neglected checking the inner wheel bearings for the past 24 years, I've ordered new inner and outers

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outer vs inner wheel bearings. F-It ordered 4 new ones
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[Jfquebec]

Wowww nice job..i need these to..thank’s for good pic

[4Hummer]

Seems my Kitfox 4 came with shielded spark plug wires. The shield grounds to the ignition box behind the firewall ( box houses the coils and mags)

problem is I can’t seem to find shielded wire anywhere. Seems Rotax stopped requiring this on the 912, I however like the idea of shielded cables

heres said box and the spark plug wires (blue). There is a metal retaining bracket that clamps the spark plug wires to the ignition box and affectively Grounds the wires (not showed)

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Old wires are falling apart, time to replace:

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Heres what I did: Ordered standard Rotax Ignition wire and 3/8 shielding, put the shielding over the ignition wire, heat shrink and zip tie near the cap, shielding stops at the ground block that houses the modules.

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New Caps
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Ignition box. Tight fit getting all the wires back in there.

There is more blue heat shrink covering the shielding where the wires go threw the firewall (Just as added protection)

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[4Hummer]

Motor mount replacement time

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Pretty easy,
Top two come right out, The bottom bolt everyone complains about (Head of bolt is against the engine case) I found if you removed the two bottom bolts on the cradle, you can just slide the whole assembly off
Easy peazy

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Jack on table, Lift a little here, lift a little there, and the rubber mounts pop right out.

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Bottom bolts, Remove the 2 bolts (17mm) that connect the engine cradle to the bottom of the engine block, and you can easily slide the bottom bolt right out still in the cradle

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[Dusty]

If you have room put a heat shield on the lower mount(I used the curved end from an oil filter with a spacer) when I replaced mine. One disc was cooked to the point of possibly been on fire at some point. Also check the crush sleeve as there was a change of specification on length. You are gunna have soo much fun with that nice plane!

[4Hummer]

Brakes Redo

Out with the old, in with the new.

Gotta say Matco is super awesome to deal with. New Masters, Rotors, Pads, Shorter Clevis's, and Nord lock washers (so I don't have to use safety wire)

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Reline tool. Don't bother with the cheaper one at aircraft spruce. This is worth the extra couple bucks,


RAPCO BRAKE RIVET TOOL
https://www.aircraftspruce.ca/catalog/topages/RapcoBrake.php?clickkey=201929

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[4Hummer]

Tail wheel time.

This setup has got to go. Look at the massive stack of washers someone used to try and fix the bent original tail spring.

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Decided on the Matco 8" Wide (single fork)
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Phat!
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Just a tad bigger....
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New Leaf springs from the wonderful people at the KitFox factory.
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The tricky part was getting the bolt out and replaced with a shorter one. No access hole and I didn't want to cut into the fabric. I found if you removed the access plate below the elevator you could use an inspection camera and spring loaded grappling hook to get the bolt in and out. It's very VERY frustrating but doable.

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Ever play that Arcade game where you try and pickup a toy with a grappling hook ? This is 100% worse than that.
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Its like playing the above game, but via a crappy camera in a cramped space, and everything is backwards
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Success
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[4Hummer]

Installed.. just have to setup the chains.

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[4Hummer]

Speed Fairings.

Belt sander makes quickish removal ridges in the PVC

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I found sanding down the ridges inside the fairing helped with fitting the jerry strut clamps, reduces the bulge a bit

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Speaking of clamps, I decided to get some no slip AN Clamps.

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Typical test fitting.
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Found a use for the stock aluminum cover Kitfox provides with the speed fairing kit....

Mixes up superfill really well.
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Fill gaps with foam, hysol together, cover in superfill, sand, rinse, repeat.
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[4Hummer]

Finished

And look the new Matco wheel is playing peek a boo in this picture

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[Carlyle]

Just stumbled upon your thread here. Nice to see a fellow kitfox a short distance away - I'm just down the road in Stratford. I see you replaced your tires with the Nanco's, mind me asking where you got them? I've been looking for quite some time, and aside from driving to walmart in the states, I haven't found a decent place to get them.

[4Hummer]

Walmart in the US, ordered online, had them delivered to the closet Walmart (Niagara Falls USA) and hopped the boarder to pick them up. I couldn't find one single vendor that carried these tires in Canada or a US Vendor that would ship to Canada at a decent price,

Stratford is super close, we will have to go Kitfoxing !

[Carlyle]

I'm not on this forum as much as I should be, but I'll try and keep an eye on your thread here. Will you be based out of YKF?

[4Hummer]

I fly out of CBL2.

[4Hummer]

Sorry for the slow updates, lot's of little things I need to finish up.. but nothing concrete as of yet. currently working on designing a dual door latch system (Latches both front and rear) and waiting for the bubble doors to arrive

I did however get the completed dash installed, pretty happy with how it turned out

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