Kitfox 4 build # 2

46 posts in this topic

Posted

Its looking good! I don't see any landing gear reinforcement on this one, are you trying to keep your weight down?I'm always impressed by how much progress you make, even more now knowing your 70.

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Posted

I infilled with about 1/8 to 3/16" of fiberglass between bottom of door and longerons.  Thanks for the compliment.  JImChuk

fiberglass reinforcement.jpg

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Posted

Jim that all looks great

 

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Posted

Thanks,  TJay,  I cut out some old lexan to fit in the triangles, and braced two boards against each inside.  The lexan laid on the boards, and gave me something to support the fiberglass on.  Fiber glass doesn't stick to lexan, so when I was done and glass was hard, it was easy to pop the lexan out.  Looks much better/smoother on the inside where it's visible.  

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Posted

OK that makes sense, I think that would be a good alternative if you didn't want to weld on a fuselage. Would it be possible for you to measure and list the control rod lengths? It can be a bit confusing to figure out what goes were when your building old kits that the labels have fallen off of. To add to the confusion I have a model IV kit and a model III and a model III to IV conversion kit. Maybe it could even be posted in the files and forms section.

Have a good day! 

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Posted (edited)

Hi Kent,  I got those control rod lengths just now, I forgot till I saw your comment again, and ran out to the garage.  Elevator is the short one, flaps are the long one.  The dumb end of the tape in the first picture shows where I measured from.  JImChuk

control rods 1.jpg

control rods 0.jpg

control rods .jpg

Edited by 1avidflyer

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Posted

Thanks for doing that Jim, are the flapperon rods the same length left and right? I imagine it will be evident when I get to that point but I’m just curious. No need to make a special trip to the garage :)

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Posted

Thanks for doing that Jim, are the flapperon rods the same length left and right? I imagine it will be evident when I get to that point but I’m just curious. No need to make a special trip to the garage :)

left side (pilot side) will be the shorter one.

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Posted

Not much progress on my Kitfox build this summer, currently I'm rebuilding a set of Kitfox 4 wings for a friend of mine.  Hope to be recovering by the end of the week.  Several weeks ago, I finally got around to sending in the registration on my Kitfox project.  I was kind of worried that the FAA would want a bit more paperwork on the ownership trail back to Skystar.   Today I looked up the N number I requested, (87JC) and there it was.  I have another airplane!   Of course, now the state sales tax people will come after me, but you can't escape that.  Anyway, I'm happy today.  Here are the wings I'm working on.   Hard to believe I have about 30 hrs into them so far.  Second one needs less work, and I made parts for both, so it'll take less time.   JImChuk

 

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Posted

Oh no you running outta projects Jim, Having to build other peoples airplanes haha

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Posted

Not really, still have a couple or three waiting in the wings.  If I get this one done, I'll get it out of my hangar.... :-)   

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Posted

Well the conditional inspection is done, and we hauled my buddy's Kitfox to the airport this weekend.  Tight fit with the Chief in there, but it worked.  JImChuk

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Posted

Well it's been quite a while since I posted anything about the Kitfox 4 build. I have been working on it a little.  Started the engine for the first time a couple of days ago.  Did it more for motivation, I was pretty sure it was going to run.  Maybe the boost of adrenaline will take me to the finish line.  JImChuk

New Kitfox 4 first engine start - YouTube

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Posted

Nice Jim! That will be a real ripper when you finish it up! If being that close doesn't fire you up I don't know what will! :BC:

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Posted

Thanks Chris.  It should do pretty good.  I was flying my 80 HP Kitfox 4 this evening, and I was doing right at 95 mph at about 5150 rpm.  Verified that with the GPS flying both ways down a road.  I imagine the 100 HP should pick up 10-15 mph more at the same rpm.  JImChuk

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Posted (edited)

Wow. I get 100 lightly loaded with a 912S in my fat avid and that is at like 5400 RPM. More like 85-90 at gross when it is hot out.

Edited by ChrisBolkan

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Posted

What radiator are you using?  I'm going with a uls in my build, and am looking at the (ugly) mods to make the larger radiator fit in the fairing.  Mind you, I'm in Texas (105 today), so it may be a no brainer (maybe run the heater in summer, to bleed off extra heat (like I had to do in my old buick (convertible!) 215 V8..?), but ..  Which way did you go?

Looking good! 

Jack, Austin, TX

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Posted

Chris,  the Kitfox 4 wing is a faster wing at higher speeds than the Avid wing as I understand it.  I know it's hard to push my Avid over 100 with the 80 HP Jabiru.  But I was flying in the Avid at 2880 RPM tonight at 84 MPH.  Verified that with the GPS flying two ways on the same stretch of road.   

Jack,  I have the standard old Kitfox radiator.  That is what I have in the other Kitfox 4 with the 80 HP and it does fine.  I never fly when it's very hot though.  When I took of this evening it was 78, but it had been up to 85 and I didn't feel like going in that.  I do have a new larger Kitfox aluminum radiator but it wont go on unless I need it.  You might end up with a radiator in the cowl, and one on the belly.  Better a bit of drag than overheating I would say.   JImChuk

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Posted

Well I'm still putzing on the new Kitfox build, I bought a Kitfox cabane style landing gear for it, and it had a set of aluminum 1 1/4" axels.  I could buy new 3/4" axels from grove for about $225, or look for some 6" wheels that use the 1 1/4" axels.   I've seen a video where a 3/4" axel broke on a grove gear, and it messed up the plane pretty quick.  I ended up making my own hubs that will still use the 8" wheels I have, and the 1 1/4" axels.  Bought some 4" long, 3" aluminum tube with 1/2" wall, and some 4" x 1/2" aluminum circles, all on ebay.  Machined things down, and took them to the welder.  Got them back yesterday, trued them up on the lathe, and pushed in the bearings.   They are done now and I think they will work just fine.  I like playing on the lathe anyway.  The dirty hub is the factory kitfox one for 3/4" axels.   JImChuk

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wheel hubs 2.jpg

wheel hubs 1.jpg

wheel hubs 0.jpg

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Posted

Looking good Jim, looks like a fun project. 

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Posted

This does look very nice for sure. Aluminum is fun to work with on a lathe. What kind of bearings do the 1 1/4 inch axle's use? It looks like some sort of sealed tapered roller just at a glance. If it is it will or should be essentially bullet proof. 

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