Kitfox 3 Bushplane Project.

210 posts in this topic

Posted

Although the rib tails were judged by Avid and Kitfox to be strong enough, when the kits were evaluated in the UK the British authorities demanded that the extra braces be put on each side of the tails to meet their (like FAA part 23) standards.  Numerous rib tails have been broken, mostly in accidents/incidents here in the U.S., so some reinforcement before covering is considered a good mod, but not mandatory here.   EDMO

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Posted

Here is the best I got.

 

 

What is the reason to do this? As long as the wood is good? The only fatality I have read about was when the wood rotted out causing a control surface failure.

 

Mine have been repaired with wooden doublers due to a flapperon contacting the ground when one of our airforce pilots was "demonstrating" it.

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Posted

Spent the day working on this thing. Cringed as I stabbed through the fuselage fabric, but got it all pulled off except the top of the tail. Powerwashed the entire airframe after I removed it all, and the hot water powerwasher removed the bits and pieces left on the tubing. Dried it out and put it back in the barn so I could yank the engine. Tomorrow Ill peel the tailfeathers and top of the tail as well as the landing gear.

The next order order of business is getting prepped for welding, going to have the wide body kit welded on, and reinforcements around the landing gear attach points and seat truss. Any tips as to the thickness and type of material to use for this? Chromoly sheet? And any pics of strategic placement of gusseting would be helpful as well, want to add some but not too much weight. 

-still getting quotes on coverings, although almost sure Im going to use stewarts

-Extended tailfeathers and trim are out, Kitfox quoted me 1150 for that kit, not including shipping which would be substantial. 

-Pretty much decided I want a 100hp timed out rotax for this now, just for ease of install

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Posted (edited)

Well felt bad making several mice homeless but spent a bit peeling the wings today, insides look pretty good minus the mouse nests, hysol bond on the leading edge of the inboard rib  broke on both wings. Gotta clean them up and re epoxy the ribs but going to wait until the new tanks get here. Going to peel the fuselage tomorrow

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Those ratefaced bastards!

Edited by LSaupe

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Posted

Tjay- what material did you use for strengthening the landing gear area? I'd like to do that and the seat truss. 

Dholly- just washed the wings, I don't see much corrosion at all except for the trailing edge angled aluminum has a bit where a nest was. Rinsed everything out repeatedly. Pulled the tanks as well. These are going into the rafters until the tanks come, if you want to come give your professional opinion you'd be welcome ;)

.035 4130

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Posted

Cant see $1150 plus shipping for electric trim larger elevators - You could modify yours for less than $100 including all parts needed.  EDMO

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Posted

Nice project. I will be watching you progress with interest as I would like to do one similar. Mike

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Posted

As far as the electric trim goes, a piece of light weight bungee cord tied to the seat truss, wrapped around the joystick, and then tied back again to the seat truss works good for trim.  Some have put a thin piece of aluminum on the stick with notches so the bungee for sure stays where you put it.  The higher up the stick you put the bungee, the more nose up trim is applied.  Cheap, simple, and effective.  JImChuk

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Posted

As far as the electric trim goes, a piece of light weight bungee cord tied to the seat truss, wrapped around the joystick, and then tied back again to the seat truss works good for trim.  Some have put a thin piece of aluminum on the stick with notches so the bungee for sure stays where you put it.  The higher up the stick you put the bungee, the more nose up trim is applied.  Cheap, simple, and effective.  JImChuk

Love it, this is what I will do , thank you sir!

On another note, have the thing completely stripped now and getting ready for welding in gussets for the longerons over the gear and the seat truss. What do yall think about just welding a plate to the outside of the fuse, instead of cutting a bunch of triangles to fit inside each opening. I would still do lightening holes to lighten it up as well. Also I will be installing Murle williams widebody so the fabric will be spaced away from those tubes anyhow (so it wont look weird with a big plate under the skin). Also thinking about adding a couple gussets to the rear above the tailwheel cluster weld, does this area ever fail? Seems like the next area that would be likely to take a hit

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Posted

On its way!

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Posted (edited)

I put this on another post by accident:  I see the different colored caps on the 912 engines - does this show HP or type of engine?

Can you use a Kitfox cowl for the 912 in an Avid?

Maybe Akflyer can answer your question about the plate welding?  I would think that a weld in the center of the tubes would be stronger, but I am not a welding engineer....

EDMO

Edited by EDMO

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Posted (edited)

Yea, Dholly was of the same opinion so that what I will do, will be fabbing up those gussets once the sheet shows up. Made some more progress today, cut and fit new floorboards, and started coating them, which should take a few days. Also stripped all of the polycarbonate off of the doors. (the specs all over the pictures is dust in my phone lens ;/

 

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Edited by Neloner

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Posted

@ Ed.  Yes, the rocker box colors do identify the engine as they come from Rotax, Green - ULS 100 hp, Black - UL 80 hp, Red - 914 turbo, 115 hp, Green or blue - 912is (injected), 100 hp.

 

 

Mine are yellow.

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Posted

Any info on these tanks, put an order in for new ones but figured I should check with you guys, these are the old ethanol susceptible tanks correct?

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Posted

Worked on the wingtips yesterday night and this morning, pulled out all the old Whelan lights, 2.7 lbs in each wingtip! Will be replacing them with the self contained LED whelan microburst lights, should save about 5 pounds out of the wings. Also had to separate the two halves of each tip so I could grind out all the old resin/ Hysol that used to hold them together and was failing. Ground down to fiberglass wiped it off good with MEK and rehysoleed it together. Also got a couple more coats on the floorboards. 

 

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Posted

I wonder if you could lose the weight and get by cheaper and get good effects by just gutting those lights and replacing the bulbs with the 30watt LED strobe bulbs from Spruce which don't need the power packs or shielded wires?  EDMO

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Posted

You definetly want the bigger tails surfaces.  I went with a Model 4 rudder and increased the elevator cord.  Wide body kit and model IV doors are also worth the effort.

Keep an eye on the GW when you start adding mods.  Not a whole lot of room to spare with a 912 if you plan on taking a passenger.

back to this, ordered a bunch of 3/8 .035 tubing to modify the tail feathers. Any specifics on the best way to do this? How big should we make them? Dholly suggested making the rudder chord longer as well as taller and wrapped over the top to the leading edge of the vertical stabilizer, which sounds good to me as long as it still fits into my barn on its trailer. Any pics or threads of anyone modding their tail feathers?

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Posted (edited)

Just keep them under the legal trailering width, which is 102" down here.  I posted some bare bones photos of my elevators in Kitfox 4 section in "FOXY FLAPPER FOTOS" showing the cutouts for trim tabs and the forward triangle-shaped tips that are used for counter balance.  I think mine are total width of 94 or 96", but not sure now - memory too old!  I increased chords of elevators, HS, VS, and rudder about 6", and increased VS and rudder height to 54" like KF4 Classic, but overlapped the rudder over the shorter VS.  I believe the cutout for the trim tab is about 24" wide x 3 or 4" deep.

  Larry, Av8r3400 posted lots of photos of his modified elevators - I think you will find them in the KF4 section too.  

EDMO

Edited by EDMO

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Posted

^Perfect I will go read up! Spending today removing glue from all the tubing

 

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Posted

^Perfect I will go read up! Spending today removing glue from all the tubing

 

Good idea! I know it might seem quicker/easier to just ask a question, but you will miss out on a wealth of info if you don't search and read thru the site here. You can target the model specific forums and skim the threads to cherry pick what might be of particular interest pretty quick.

In addition to Av8r3400's MangyFox KF4 rebuild thread, I would recommend LSaupe's build posts in the KF III Forum:

See: Home > General Category > Kitfox General Forum > Kitfox III

_______________________

Re: my tail mod suggestions... the KF 4-1200 added 2" to the rudder chord and the rudder and V.S. were both increased 7" in height vs. the KF III, both will be easy to incorporate in the repair. As suggested, the additional height can be in the form of a balanced rudder. Pic is my A+ tail for reference of what I was trying to describe.

Also, the KF 4-1200 added additional bracing to the vertical fin. Not sure exactly where this was. I would search here to find some pics of an uncovered fuse to compare to your model 3, it might be something easy to add when we do the longeron gussets. FWIW, I posted pics of a bare KF 3 and KF 4-1050 fuse side-by-side in a Classified Ad onsite HERE and would note the tailpost and tailspring area are identical. If you are planning a big tail wheel, you might want to check for some strengthening ideas from the KF 4-1200 for this area as well. (P.S. - I may have included some pics of the new style drag tube and jury strut brackets in the 4-1050 wing kit.)

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Posted

Yea that rudder looks nice Doug, Ill take some measurements to figure out my limitation on height. I need to be able to pull it into my barn while its on its trailer, although I could also drop the tailwheel perch on the trailer as well if need be. Ordered 32' of 3/8" .035 moly tubing, got enough to play with the elevators as well if your buddies are up for it, may end up doing that electric trim tab as well, read through those threads you suggested and doesn't look too complicated to add in. 

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Posted

I used square tubing in the opening for my trim tab - looked like it would be easier to attach the piano hinge to that.  EDMO

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Posted

I was thinking about the mouse pee issue again, you absolutely need to stop the caustic corrosion as washing and rinsing just doesn't do it. The only way to guaranty permanent elimination is with a enzymatic cleaner that pulls the pee out and eats it up. Yum.

So anyhoo, my mind turned to the 'Nature's Miracle Super-Oxygenated Stain & Odor Remover' product we used to clean up after one of our Black Labs suffered from canine epilepsy. It is an oxygen-infused, bio-enzymatic formula designed to react to organic stain and odor matter and works to eliminate any traces of urine, feces, drool, vomit and other pet messes, strong pet urine odors, yellow stains and the sticky residue left behind after pet urine is efficiently removed. Great stuff, we bought it by the gallon and couldn't live without that and the carpet steamer. (R.I.P. Sophie Girl ^-^).

Thinking it might be worth following up on, I posted the question to the manufacturer's online "Ask The Expert" FAQ forum and got an answer:

Q.) Hi, I have found mouse nests, droppings and urine in my stockpile of 2.5" dia. x .065" wall 6061 T6 aluminum tubing. Which product(s) would be best for cleanup and effectively neutralizing the long term corrosive effects of mouse urine? Thank you.

A.) Thanks for asking! The best product to tackle the mouse mess is our Advanced Stain & Odor Remover. As long as it remains wet it will continue to 'eat' the urine until it is completely eliminated. You may want to use a garden sprayer, or purchase one of our battery powered units, to make sure the spray reaches the inside of the tubing.

Wife says it cost about $20-25/gal. at WallyWorld, PetSmart etc. Don't buy the Advanced Formula, it just adds some fragrance which we found both redundant unnecessary as you are eliminating all odor anyways (kudos to the marketing team I guess). So there you have one good, cheap (at least, relatively to the AlumiPrep/Alodine treatment) mouse pee neutralizing option that should work and provide peace of mind. You sure don't want to fly or pass along a plane knowing it has a spar corrosion issue when it can be resolved so easily, IMHO. According to the Directions you must saturate the areas, maybe more than once, and let dry naturally. Best to treat your wings ASAP so the ribs will be completely dry by recovering time.

Directions:

Stain Removal:

  • Wipe away any excess stain-causing material, and then soak the surface thoroughly with Nature’s Miracle Stain and Odor Remover.
  • Wait 5 minutes, and then wipe away stain with a cloth. For tough stains, use a stiff, bristle brush.
  • If the stain is not completely removed, re-soak area and allow Nature’s Miracle Stain and Odor Remover to work for 1 hour before wiping with a cloth.

Odor Elimination:

  • Thoroughly soak the entire area with Nature’s Miracle Stain and Odor Remover. For carpets, apply enough to reach the urine penetration in the pad and floor. This may mean lifting the carpet and applying directly to the pad and floor.
  • Allow the product to air dry. Depending on air circulation, carpets and upholstery may take up to 2 weeks to dry completely.
  • If after 2 weeks there is still an odor, Nature’s Miracle Stain and Odor Remover has not reached ALL of the odor-causing material. Pinpoint odor source and repeat cleaning process.
  • Keep the product away from children and pets and do not allow pets onto the treated area until it is completely dried.

Tips:

  • Always test surfaces to be treated for color fastness by applying to a hidden area and wiping with a cloth. If color is removed from the test area, do not use Stain and Odor Remover on this surface.
  • Always use Stain and Odor Remover at full strength for best results.
  • Use Nature’s Miracle Stain and Odor Remover before any other product as cleansers and detergents may chemically “set” the stain.
  • Stain and Odor Remover is not recommended for use on silks, leather, or suede.
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Posted (edited)

Might be cheaper and easier to just replace the section of trailing edge that has the corrosion on it?  Spar corrosion would be something more serious.  EDMO

Edited by EDMO

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Posted

Well, the pee has ammonia in it, which is a base. I have found that a mild acid will neutralize the ammonia. NOT that there aren't corrosive properties with an acid. It needs to be washed off thoroughly with water. 

Alumaprep is a mild acid, isn't it?.................  HA!!! Just looked, phosphoric acid is in Alumaprep. :P

BTW I have a rescue dog that had a few accidents on the carpet before we came to an agreement. Vinegar and a wet shop vac is your friend! ;)

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