Greetings from a KF3 kit owner

[Landcruisinmy93 5]

Greetings from Oregon. My name is Steve and I have a problem, Lol.

          I just bought a new to me, 3 owner, never assembled Kitfox model 3 assortment of randomness! Or at least I'm pretty sure it is a model 3. I have a fuselage in great shape. an assortment of random stuff that definitely doesn't belong to the aircraft, Kitfox 2 ailerons? and Kitfox 3 ailerons? 3 sets of door frames, too few wing ribs of which there are 2 types... you get the picture. I really didn't know what I was looking at when I drove 10 hours one way to pick it up. there was just so much stuff. I knew I had a couple of missing ribs and that the butt ribs and false ribs weren't present. However, I didn't realize how much stuff was really missing until I started going through and taking stock of what I had and taking stock of the 2 copies of the manual it came with, which itself was missing several pages and a few sections. I spoke with John McBean and ordered the digital copy for the model 3. At least one thing is now complete. 

          SOOOOO, I may or may not be building a Kitfox in the near future. If / When I do, I will keep everyone apprised of the progress. Meanwhile, I'm scouring the forums and the interwebs of things, stuff and whatnot for all of the information I can find. So far I have determined I might have some avid wing ribs and some model 4 ribs, Lol. If anyone can give me some quick identifiers to check the fuselage for model accuracy I would appreciate it. 

I would like to say thank you to 1AvidFlyer and Willja67 for responding to my posts and messages seeking assistance. They have both been a lot of help so far and have made me feel welcomed to the forum. Thank You, you two.

 

[1avidflyer 1983]

Hi Steve,  maybe if you can post some pictures of the ribs you have and such, we may be able to help you figure out what you have.  I don't remember if the Kitfox 2 and 3 have the serial stamped on the fuselage, but on the Kitfox 4 it is where the seatbelts connect in the center of the plane up above the flaperon mixer controls.  Kitfox 2 and 3 flaperons are the same, and are 6" wide with a flat bottom.  Kitfox 4 are 8" wide with a equal curve top and bottom.  I would suggest that you post as many pictures as you can when you have a question so it will help us to see what you are referring to if there is any confusion.  I got a kick out of how you introduced yourself.  Sounds like you just joined Aircraft Owners Anonymous and you are introducing your self to the other addicts in the room.    JImChuk

[Landcruisinmy93 5]

         Jim! That introduction was intended to sound exactly as you read it. I have so many questions now about the flaperons. I have identified the wing ribs as model 3 undercamber style and the others...the ones I have the most of as a model 4 design but with one dissimilarity from the ones I have seen pictures of.

          I have looked for a serial number in the location you mentioned and haven't found one. Due to the flaperon control mounting setup and parts I have, it looks like it is a model 3.

I'm not sure where to measure width but the spar carry through is just over 1" OD and apx 0.0625" thick as far as I can tell and it measures apx. 37.125" and to end. The cabin measures apx 39.375" at its widest point near the seat pan bend.

          The elevator is apx 13.375" wide at the widest point of its chord; and the rudder 15.50" wide at its widest point of its chord. The rudder stands 47" tall top to bottom.

          The Flaperon mystery continues. One pair is 8" wide and has angled brackets and the other pair 10" wide with straight brackets. 

Edited 8 Aug 2021 by Landcruisinmy93
Add pictures

[1avidflyer 1983]

Looking at the ribs, I would say the bottom one is a Kitfox 4 or newer rib, the other ones are Kitfox 3 or earlier.  Top rib has the long tail which the flaperon hinges off of.  Middle rib is the rib in between the long tailed ribs.  Narrow flaperon is early Kitfox or Avid,  wider flaperon is Kitfox 4 or new style.  JImChuk

[Av8r_Sed 82]

With the discussion on MIII ribs, when you do get to building, know that the plywood rib tails to support the flaperons should get reinforced somehow. That’s not in the manual, but is a known weak point in the earlier models. Mine have aluminum laminated on either side, but there are many ways to do it. 

[Landcruisinmy93 5]

Looking at the ribs, I would say the bottom one is a Kitfox 4 or newer rib, the other ones are Kitfox 3 or earlier.  Top rib has the long tail which the flaperon hinges off of.  Middle rib is the rib in between the long tailed ribs.  Narrow flaperon is early Kitfox or Avid,  wider flaperon is Kitfox 4 or new style.  JImChuk.

Jim your cup runneth over with Kitfox and Avid knowledge. I really appreciate all of your input.

With the discussion on MIII ribs, when you do get to building, know that the plywood rib tails to support the flaperons should get reinforced somehow. That’s not in the manual, but is a known weak point in the earlier models. Mine have aluminum laminated on either side, but there are many ways to do it. 

          I read that the earlier non- reinforced ribs had an AD or maybe it was just a Kitfox service bulletin requiring reinforcement. I believe it mentions using aluminum on both sides of the rails. 

          Does anyone happen to know the dimensions of the model 4-1200 tail control surfaces? Height and chord of rudder at the widest part and the width and chord of the elevator at its widest location?  

          I believe I will add an elevator trim tab, or depending on which control surfaces I have, I may just order a 4 rudder and elevator with trim tab setup instead of chopping mine up. 

 

[1avidflyer 1983]

When I rebuilt my Kitfox 4, I added a trim tab to the elevator.  I use a Ray Allen electric servo to control the trim.  It doesn't move very fast so now I only use it for keeping the plane level in flight.   I rigged up something else for trim on landing that was much quicker.  Adding a touch of flaps will give nose down trim,  so if I had to do it all over again, I'm not sure I would go thru all the effort of adding a trim tab to the rudder.  Here is a picture of my landing trim.