Kitfox 4 rebuild

42 posts in this topic

Posted

Well I thought about naming this topic, As naked as she can be!, but that would really only be describing this first post.  Would have probably had lots of one time views though! ;-)  Just about all that's left on her is paint.  I'll strip that off after I widen the fuselage, and add bracing above the landing gear.  I do have a question though for other Kitfox 4 owners.  In my experience, Avids are almost always nose heavy, even with a 2 stroke.  On my recent Avid MK IV rebuild, I mounted the battery as far back as I could get it to help offset this.  I'm going to be using a 912 Rotax on this Kitfox 4, and am wondering if I should make any provision for mounting the battery near the back for weight and balance issues?  I know some of the Kitfoxes have the battery on the firewall, this plane had it behind the turtle deck, but he was trying to offset a heavy Subaru engine.  Anyway, as I progress on this plane, I'll be adding to this thread.  Studying Larry's Mangy fox rebuild thread some as well.  I see his weight came in a just over 700 lbs,  what do others have for their Kitfox 4 empty weight?  JImChuk

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Posted

How do you find the time for all them airplanes Jim? Heck you might have more than the North Korean Air Force ;-) Will be watching this with great interest. Mike

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Posted

Actually it's been a bit of a slow process with these planes.  I got the Kitfox 1 flying about 9 months after I got it.  The Avid MK IV took about 6 years after I wrecked it.   This Kitfox 4 came from Texas 4 or 5 years ago.  I don't work on them all the time either.   Lately now with this Kitfox 4 I'm kind of pushing on it cause I want to get the fuselage painted before it gets to cold outside.  My work stall is heated, but not well enough to pull a lot of fresh air through there when I'm painting.  I figure to paint the fuse, and then I can mess with it in the winter at a bit of a more relaxed pace.  Going south for a while then as well, so if it flys next summer I'll be happy.  JImChuk 

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Posted

Wouldn't matter with your 4 I suppose, but fwiw my 5 came in at 680lbs witht the e81.  Battery below turtledeck.

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Posted

Wow, that was light for your 5 at 680 lbs.  My kitfox 4 was over 800.  It did seem like they did everything they could to make it heavy though.  I'll bet I cut 5 lbs of zip ties off of it. :-)  Had about 20 lbs of weight in the tail, a 1200 lb BR$, ect, ect.  That would be 50 lbs right there between those items.  JImChuk

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Posted

For comparison, the Mangy is 700#.  My old 4-1050 was 648#. 

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Posted

I will be happy if I keep it below 650. JImChuk

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Posted (edited)

I know that Kitfox probably wants to keep empty weight figures as light or sellable as possible, but here is what is in my Kitfox Pilot's Guide.

Kitfox 4 Classic / Lite Squared 912:  Average empty weight - 600 lbs.

Kitfox 4 Classic / Lite Squared 912S:  625 lbs.

Kitfox 5/1400-912:  700 lbs.

Kitfox 5/1400-912S:  750 lbs.

I don't see how a Kitfox 5 with EA81 could come in at under the average weight of one with a lighter 912 engine, but guess anything is possible?  ???   I wonder how many were weighed with bathroom scales?

EDMO

Edited by EDMO

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Posted

Well the data plate on mine says 626 lbs with the Subaru.  A later W&B sheet shows the 800 something weight.  I think was first one was a guess at best.  JImChuk

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Posted

626 with a Subaru?   Now that's funny right there!

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Posted

I'm watching with interest, JimChuck.  I just picked up a partially completed Model IV kit.  I've got to back up a little and take care of some corrosion, old fuel tanks and the like before any progress starts.  It'll be interesting to see how light you'll be able to keep it.

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Posted (edited)

Guess I will get shot down and go down in a trail of smoke on this one?  If I was landing on sandbars and such I would try to build light - However, here in the flatlands full of long runways I am more comfortable pushing the upper limits on weight - I don't like getting bounced around in a light bird.  I don't try to do STOL show flying - mostly 100 to 200 mile or more, cross country flights.  EDMO

Edited by EDMO

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Posted

I wont shoot at you Ed.  But if I build light, I can always load it up to be heavier.  Can't go the other way though.  I will agree with you on not liking getting bounced around in flight.  I do most of my flying later in the evening before sunset.  JImChuk

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Posted (edited)

I wont shoot at you Ed.  But if I build light, I can always load it up to be heavier.  Can't go the other way though.  I will agree with you on not liking getting bounced around in flight.  I do most of my flying later in the evening before sunset.  JImChuk

I cant argue with building light and hauling more - my "more" is in the engine and extra tanks, which can be used for long trips or left empty for short hauls - I usually fly solo and very light on luggage.  It has a lot to do with my "Night-shifter" life - My flying buddy is doing his preflight before the sun comes up and takes off in smooth air and lands before it gets rough - I go to bed a couple of hours before that and don't get started until about noon and get all the thermal bounces and x-winds!  I loved to fly at night since it is usually smooth air, but cant do that now with SP - Just our own choices.  ;<)  EDMO

Edited by EDMO

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Posted

Just got the fuselage back from the welder.  I cut and fit everything, and had him tig weld it.  Fuselage will be 4" wider than stock.   Next step is sandblasting.  Not looking forward to that though.  JImChuk

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Posted

Looks good Jim

You gonna stick around this winter to finish it up

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Posted

No, but I've got a couple of months before I go.  I'm not staying as long this winter either.   If it flys next summer, I'll be happy.  Looks like the hurricane didn't hurt Gulf Shores, so the condo in most likely still in one piece.  JImChuk

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Posted

Busy for a bit yesterday and today.  Got the sandblaster to work, and used it a couple  of hours today.  Should finish tomorrow if other things don't get in the way to much.  Maybe paint Wednesday?? Hope hope.  JImChuk

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Posted

JimChuk,

I'm amazed at what you can do with simple home shop tools! :rolleyes:  Did you raid the local public works department?

How many pounds of sand did that take?

 

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Posted

Well it took quite a bit of work to get the compressor and sandblaster to work.  My brother was always buying junk at auctions.  buy it, bring it home, and then it would sit and rust.  He had a stroke several years ago, and I got to clean up the mess.  As far as the sand goes, I had a 5 gallon bucket of silica sand, so I tried that first.  I also have some bags of garnet sandblasting grit, but wanted to try the silica first cause I figured it wouldn't be as aggressive on the tubing.  It worked real well so, got some more of the silica.  I did end up mixing the silica with a bag of garnet fine grit I had.  I put a big plastic tarp down, and reclaimed most of the sand and reused it.  Ran it through a window screen to get any big chunks out before it went back into the sandblaster.  Seems to work fine so far.  I imagine the sand will get smaller the more times it's used, so will be less effective.  I've got the 5 gallons plus two 50 lb bags of silica and the one 80 lb bag of fine grit garnet media in the blaster now.  Could get by with less, but would have to refill more often.   About $25 for the silica and grit.  JImChuk

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Posted

Just remember, and I am sure you know, that silica is not anything you want in your lungs. Awesome set up, just make sure you are protecting your innards!

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Posted (edited)

We bought two 50 lb bags of kid's play sand and ran it thru a screen - put the J3 fuselage on a couple of tarps to save the sand and used a 100 lb pressure pot blaster with a large Sears vertical air compressor - worked good.  EDMO

Edited by EDMO

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Posted

Thanks for the info.  Makes me a little jealous.  No place to blast, even if I had the equipment.  I hope to find a deal like Larry did to blast and powdercoat when I'm ready.

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Posted

Well it took quite a bit of work to get the compressor and sandblaster to work.  My brother was always buying junk at auctions.  buy it, bring it home, and then it would sit and rust.  He had a stroke several years ago, and I got to clean up the mess.  As far as the sand goes, I had a 5 gallon bucket of silica sand, so I tried that first.  I also have some bags of garnet sandblasting grit, but wanted to try the silica first cause I figured it wouldn't be as aggressive on the tubing.  It worked real well so, got some more of the silica.  I did end up mixing the silica with a bag of garnet fine grit I had.  I put a big plastic tarp down, and reclaimed most of the sand and reused it.  Ran it through a window screen to get any big chunks out before it went back into the sandblaster.  Seems to work fine so far.  I imagine the sand will get smaller the more times it's used, so will be less effective.  I've got the 5 gallons plus two 50 lb bags of silica and the one 80 lb bag of fine grit garnet media in the blaster now.  Could get by with less, but would have to refill more often.   About $25 for the silica and grit.  JImChuk

Seems like you can reuse the sand once or twice but after that the sharpness is gone and takes way more time. Just my experiences with blasting

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Posted

Had a little time to sandblast today, but didn't finish.  The sandblaster was kind of pulsating for some reason.  It would throw out about a half a teaspoon full of sand every half second or so.  When I would adjust it for less sand, it would slowly quit sending out sand.  I still made some progress, although I've come down with a sore throat and cold it seems.  Between sneezing and blowing snot all over the place, it wasn't as much fun as I was expecting for today.... :-)  JImChuk

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