Bringing a Kitfox 1 back to life

[Good old number 29 158]

Having a bit of trouble getting pics to upload. Our internet has been having issues. 

[1avidflyer 1983]

Hope I'm wrong, but that rib tail looks ugly...  Is that dark area from moisture?  Maybe rot??? Ouch.  If it comes to it, here are two ways to replace the rib tails.  Not that hard for you to make.  These were for an Avid Flyer, but the Kitfox is very similar.   JImChuk

[Good old number 29 158]

Jim,

I need to replace at least five false ribs. Some were repaired or warped, so I could use as many as ten. I just got word that the wing tanks won’t be ready for six weeks, instead of 3-4 weeks from when I ordered them. I’ve decided to proceed without them, so I can get the covering done before it gets super cold. Maybe next year I’ll do the fabric on the fuselage when I fit the tanks. 

[Good old number 29 158]

Yes, that hanger rib is highly questionable. It’s the inboard one on the left wing. Looks to me like it was installed with that warp in it, or at least some pressure that direction. The discoloration is from moisture, but it’s not soft. It does have a little split in that kink. I’ve been kicking around different ideas on the repair. My uncle is coming to take a look at it, to help make the reinforcing brackets. He’s a retired sheetmetal worker, and flies a C-180. It’s great that he’s willing to help, since he has a sheet metal brake and a bit of expertise that I don’t have. I’m going to do all of the flapperon hanger ribs. It might be good to make the brackets longer than specified, to give a little more strength. 

[Good old number 29 158]

It’s placarded as being 414 lb. empty. My scale, adding 8% for known inaccuracy, had it at 400, minus the battery and wing tank. I’m going to shoot for making it that 400 lb, 52 hp Rotax 503 powered Kitfox of legend. Then I’ll add the wing tanks so I can actually go places. 

[Good old number 29 158]

Here is a link to my original posts in the other forum, in case anyone wants to see the full story. 

http://www.teamkitfox.com/Forums/showthread.php?p=77511&posted=1#post77511

[Good old number 29 158]

It’s been a busy few days, but I managed to make progress in spite of it. Got the other wing spars cleaned up and primed. Pretty happy with the results. I pulled off the shortened drag/anti-drag tube that was installed in the bay next to the old wing tank. The tubing to make a new and proper replacement is in the mail. Should be here tomorrow. I also pulled off the brackets that were used to mount the sheet metal wing tank cover. I’ll need to rivet a bandaid in its place. The big thing that I managed to do lots of, is spend money. Nine hours of driving, on Friday, netted me the fabric, all the coatings, including paint, the sheet metal to make the flaperon reinforcement brackets, and handfuls of other parts and tools. I also picked up a new intercom. The only other big thing I might buy is a prop. I’ve been leaning toward getting a Power Fin. 

I’m getting close to the point that I can re-cover the wings. Still waiting on the main bearings, so I can finish the motor. 

I sold my motorcycle, tonight. I hated to see it go, but it’s for a good cause. I already sold my little skiff to help finance this project. 

And, still having problems posting pics. Seems like smaller ones do okay, but I don’t like messing around, trying to make them little enough to post. 

In light of the corrosion issues with my spars, I HIGHLY recommend that you prime the bare aluminum in the wings before assembling and covering them. Proper prep is key to a good coating, and it is well worth it. Considering that my plane is thirty years old, the bare aluminum spars did pretty good. But, if they had been properly primed, it would have saved me a lot of time and work, and wouldn’t have had any corrosion, at all. In fact, I might not even have needed to pull the fabric, if the oxidation hadn’t caused the false ribs to let loose. When I cleaned the spars, prior to priming, I found that some of the epoxy (Hysol or Scotch-Weld) fastening the ribs to the spars, had blistered. I found this after I cleaned up the first wing. There was some blistering evident on the second wing, prior to paint prep. I cleaned all of the blistered adhesive away from the ribs prior to priming, and was more careful with the MEK when I cleaned up the second rib, in case that had been a factor. 

 

Edited 24 Sep 2018 by Good old number 29
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[Good old number 29 158]

I got the new windshield installed, this afternoon. Replaced the brake pads, packed the wheel bearings, and put it back on the wheels. I’m still looking at how I want to change the brake brackets. It looks like the master cylinders were replaced with longer units than original. The mounting brackets had been moved further up, reducing leverage, but weren’t moved far enough to get the right angle for the brake pedals, as relating to the rudder pedals. The brakes did work okay. You just couldn’t stay off them, using the rudder. Someone with a buzzbox stuck them on with 6011, as evidenced by the welds. I cut the tabs off, and ground off most of the built-up weld. I haven’t quite talked myself into moving the bracket clear to the top of the pedal to see if it works, but I think I’ll give it a shot. Not a lot of good options on it. 

[1avidflyer 1983]

Can you adjust the y on top of the master cylinder downward, so the pedals can tip more forward?  On the older Matcos with the 1/4" shaft, there is about 3/4" of thread, and you only need 3/8" of it.  Even if you cut the threads a bit further down the rod, and cut some off the top of the shaft.  The higher up you go on the tabs, the worse the brakes will be for holding power.  I'm right in the middle of making new brake pedals for my Avid right now.  Wish I had some pics handy.   JImChuk

[dholly 718]

Man, that's a lot of holes in the spars. Does not give me the warm fuzzy feeling, not sure what I'd do about it though.

[Good old number 29 158]

Yeah, those holes are not what I would have done to attach a wing tank cover. He put a bunch of holes in the ribs and cap strips, too. The front spar has four, 1/4” holes with threaded insert rivets in them. I guess I’ll leave the riveted holes on that one, but plate the back spar. There was a bracket riveted there, to which the cover plate was screwed, following a repair to the tank. Not how I would have done it. My plan is to cut a reinforcing plate, with radiused corners, so it doesn’t have hard edges, and rivet it to the spar, using the same holes. I can use the old bracket as a template to line up the holes. Rivet and bond it to the spar. 

[Good old number 29 158]

The shaft has a larger diameter below the threads, so I can’t just cut more threads. I can gain a little by trimming the top 3/8” off the threads, but it won’t be quite enough. I could put blocks on the rudder pedals, but I like the leg reach it has now. 

[TJay 1041]

you can gain more threads you just have to grind down the shaft a bit on the bench grinder then thread it further down. Its a pain but easier than spending money on new ones ha at least thats what I did. Good luck

[TJay 1041]

I also cut my pedals apart added 3/8th on an inch and tipped them back a bit I now love how the setup feels. Just a thought for you.

[Good old number 29 158]

That’s a nice setup, TJay. I got mine figured out. Just waiting for the paint to dry. I cut enough threads off to spin it all the way down, and welded the pad eyes back on slightly higher. 

I also got the doubling plates welded on the spars. 

[Good old number 29 158]

That’s a good point about being able to grind down the shaft diameter. I didn’t try anything like that, because I wasn’t exactly sure about piston stroke, and I didn’t want to come up short on my seals. I haven’t bled the brakes since I reinstalled them, but I know I have at least half an inch. I actually needed an inch and a half, though. How I have it now isn’t much different geometry than when I got it, and the brakes worked okay. The angle on the pedals is really nice, now. Feet make even contact on both rudder and brake pedals, and just a little toe to give it brakes. 

[1avidflyer 1983]

If the brakes are blead good, you will probably not need a lot of travel on the master cylinders to give it good brakes.  Matt, your package will be in the post office in the morning.  JImChuk

[Good old number 29 158]

Thanks, Jim. Getting closer to closing the wings back up  

I got my flaperon hanger rib reinforcing brackets made today. I’m taking some time to relax, this evening, and I’ll get them fitted tomorrow. 

I’ll get the old props boxed up and sent off tomorrow, too, if I can. I need to take a little time to square away the wiring, too. I wish those crank bearings would show up. Several items have been back ordered, and I’m waiting for them to ship. 

[flywise 169]

Man, that's a lot of holes in the spars. Does not give me the warm fuzzy feeling, not sure what I'd do about it though.

I am quite sure the spars were never designed to be drilled out at that location with so many holes.....  Any engineer to chime in about these drilled spars????

[akflyer 1427]

Man, that's a lot of holes in the spars. Does not give me the warm fuzzy feeling, not sure what I'd do about it though.

I am quite sure the spars were never designed to be drilled out at that location with so many holes.....  Any engineer to chime in about these drilled spars????

I was thinking the same thing.  I think I would make a plate that covered that area (something like the strut attach fittings) and glue it down and reinstall the rivets.  All those open holes in that area does not give me a warm fuzzy either.

[Good old number 29 158]

Not mentioning any names, but those holes were made by an A&P in Soldotna. I could hardly believe that anyone would do that, but I got the receipt for his work, from the previous owner, when I bought the plane. That same mechanic replaced the fan belt, and the fan blew up right after takeoff, on the test flight. They did a quick turnaround and dead stick landing on the runway. The owner did the repair work after that incident. 

My plan has been to do exactly as AKFlyer suggested. I got the doubling plate cut and rolled, yesterday. I’ll make radiused cuts in the ends, so it doesn’t have a hard, straight edge making a break point. Then, I’ll bond it to the spar with epoxy, and pin it with Cherrymax structural rivets. Twenty three holes in the spars in one bay, to attach a wing tank cover, with dozens of holes in the ribs and cap strips, too. Why, oh why, would anyone do that? Nineteen holes in the rear spar, and four in the front. I mean, I can fix it, but that is seriously ridiculous. Oh, and when I got it, that wing tank still leaked. 

[Allen Sutphin 705]

I've been an A&P for 40+ years and still won't drill holes in any spar unless instructed to do so by the instructions for that specific part. And generally there are other methods and ways to accomplish the task with out weakening a spar or part. One could fill in those holes with a TIG welder, but not everyone has one available.  Unfortunately there isn't a easy simple fix for it without looking like a fix.  One or two holes isn't a big issue but that many in a row should have raised a flag to an A&P. Or anybody else for that matter.  You wouldn't believe some of the things I've seen owners and mechanics do in my 40+ years. And it will continue long after I am gone!  Maybe I am just too darn picky!

[Good old number 29 158]

Got my “band-aid” cut and drilled, flaperon brackets fitted and drilled, and false ribs attached on the right wing. I drilled the rivets and removed the skylight out of the turtle deck. My wife texted me, two hours ago, about all the things she did in the house. I’d say that I think she’s great, but I think that’s missing the point. 

[Allen Sutphin 705]

I'll say one thing, you sure are going to town on that airframe. You just might make it in a month. Me, I am just getting caught up on pre-winter chores and working on the fox when time permits. A lot to do on 14 ac. w/6 ac of grass to mow. Either that or I am slowing down in my golden years.

[Good old number 29 158]

Hmm. Somebody forgot to take pictures, today.

I had a great trip to Girdwood, with my wife, and did some hiking around Alyeska over the weekend. Totally off topic, but these are the things in life that really matter. I’m just thankful to God for all the goodness in my life. I’ve been wanting to say how proud I am of my daughter, too. She beat four girls in 100yd backstroke, in high school swimming. With no legs. She lost both legs above the knee in an accident on Christmas, 2014. It’s pretty awesome to have seen her come so far. Ski season is coming up, and she’s excited about that. Two of our boys got in a motorcycle wreck, a week or so, ago. They’re okay. The young one is proud of it.

So, today I realized that the rivets spec’ed in the service bulletin are not the right length for attaching the reinforcing brackets to the flaperon hanger ribs. After I had them in place, and covered with adhesive. Good thing it comes off with paint thinner. The length specified was only the thickness of the material, and didn’t account for proper protrusion. Put them on my list and bought the rivets without thinking any more about what length they ought to be. I did get the tubing for the wing rib braces and anti-drag diagonal brace in place, where the wing tank was. I got the false ribs that Jim sent. Still have to stick them on the other wing. I might need to make another run to Anchorage to get the right rivets, so I can cover the wings. Eh. Maybe MARC has them in Soldotna. I should be so lucky. I got the “band-aid” riveted in place on the rear spar. It looks good. Still can’t believe he put so many holes in the spar. 

I’ve crossed a lot of things off my list. Down to three dozen. Realistically, it’s about half a dozen. False ribs, covering, engine reassembly, prop, odds and ends. I’ve been thinking that I need to stick some lights on it.