Kitfox 4 rebuild

246 posts in this topic

Posted

Situations like these keep me from wanting a 912. I think I'll save my pennies for a bird with a Cont or Lyco on the nose. They may be old, outdated, heavy and came here on the Mayflower, but they are pretty simple and reliable. I know from all reports that the 912 is a great engine, or at least till something starts going south.

I just flew a Scout that a friend bought, up from Colorado today.  Great airplane, O-360 constant speed prop. It flew a little slower than my Avid and burned 10.1 g/hr .Costs around 2.5 times what my MK IV would sell for ($80,000+ USD) and I can tell you that I would not trade my plane for it for it even if he kicked in $10,000.  The Avid is a lot more fun to fly.  The Scout is definitely a great plane and will fit his mission well. I can fly it anytime I want but doubt that I will just because, for me the Avid is just a GREAT little plane and did I mention FUN TO FLY.  

All engines suck when you are having problems with them and life is good when they are running good.  Finish that plane up Allen and come on out and have some fun!

i feel for you Jim and have been thinking about your issues, hope you find it soon.

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Posted

Thanks Laurent,  you mention stator coils, and maybe I'm thinking wrong, (not the first time)  but do you mean trigger coils?  In my mind, I thinking the stator coils are what do the charging.  Which I've wondered about as well.  I can't get the tach on my MGL engine monitor to function correctly either and it does read pulses off the charging system.  I wouldn't have thought the charging system should make it run poorly, that's the ignition systems fault if my problem is electrical.  At least that's what seems right to me.  Then again, there is no telling what little tricks Rotax had up their sleeve just to mess with people like me.  :-)...  I switched the modules and coils from the other engine today, and no better.  Even rigged up a gravity feed fuel tank, and that did nothing to improve things.  I pulled a cylinder off the spare engine to day to have a look and see if there is any evidence of corrosion inside.  Looked perfect, cam lobes were nice and shiney.  Unfortunatly when I was putting the cylinder back on, I cracked an oil ring, so there goes another holdup.  Plus about $65 after shipping as well.  So now I have the spare engine sitting on a cart, and I'll pull the engine off that doesn't want to run smooth and let it take a rest.  Before I take a sledge hammer to it....  The saga continues..... JImChuk

PS  See Allen, I told you we were crazy.... Who in their right mind would put themselves through this and come back for more?

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Posted (edited)

Thanks Laurent,  you mention stator coils, and maybe I'm thinking wrong, (not the first time)  but do you mean trigger coils?  In my mind, I thinking the stator coils are what do the charging.  Which I've wondered about as well.  I can't get the tach on my MGL engine monitor to function correctly either and it does read pulses off the charging system.  I wouldn't have thought the charging system should make it run poorly, that's the ignition systems fault if my problem is electrical.  At least that's what seems right to me.  Then again, there is no telling what little tricks Rotax had up their sleeve just to mess with people like me.  :-)...  I switched the modules and coils from the other engine today, and no better.  Even rigged up a gravity feed fuel tank, and that did nothing to improve things.  I pulled a cylinder off the spare engine to day to have a look and see if there is any evidence of corrosion inside.  Looked perfect, cam lobes were nice and shiney.  Unfortunatly when I was putting the cylinder back on, I cracked an oil ring, so there goes another holdup.  Plus about $65 after shipping as well.  So now I have the spare engine sitting on a cart, and I'll pull the engine off that doesn't want to run smooth and let it take a rest.  Before I take a sledge hammer to it....  The saga continues..... JImChuk

PS  See Allen, I told you we were crazy.... Who in their right mind would put themselves through this and come back for more?

Hey Jim,

I can feel what you're going through...I nearly lost my mind when I did have my rough running..

Anyhow when you get it going you'll forget the hard time troubleshooting. One thing for sure, you will know your engine inside-out:)

Concerning the coils....you have 8 coils producing electric current for your aircraft (250W) and then you have an additional 2 'ignition' coils producing electricity (unregulated AC) to power each your ignition modules (that way your engine ignition has always power). These are the coils you have to check. Also note the two red wires, they are the ones feeding your modules. Also check these wires as they were a problem / shorting out on some harness against the shielding (intermittent problem). So when you check your two coils through the red wires, wiggle the harness around and check continuity at the same time. Hope that helps,

Keep going..

Screen Shot 2020-08-26 at 8.21.51 PM.png

Edited by flywise
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Posted

I've been not keeping up on this thread, mostly cause it was a bunch of work in another direction.  I pulled out the 912 that was missbehaving, and installed the other one.  At any rate, I got it all installed, and it runs good.  No gas puking out of the overflow tubes on this one.  Conditional inspection tomorrow morning, so looks like I'm almost done.  I was out in the hangar till 9:30 tonight though.  Couple of little things that I had missed.  Had to tighten up the flap handle as well.  Looks like I have a just barely weeping fuel fitting on the plastic header tank, I guess the AnP needs to find something.  JImChuk

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Posted

Hope the condition insp goes well. Many of those poly header tanks weep. They expand and contract with the temps and seem to always seep. One reason I went to an alum header tank. A&P's can always find some little thing they don't like. We have a lot of pet peeves when it comes to airplanes. Mine, I hate zip ties around engine mount tubes. They cause corrosion to start on the tube. Has to do with the chemicals used in the zip ties. See we're all crazy!

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Posted


Good luck Jim hope its flying by tonight.

 

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Posted

AnP left a bit ago, a few minor issues to address.  Will be good to by this evening most likely.  Still have to inform the FAA about the major changes, engine and propeller, plus state registration of a flying aircraft (no charge for unairworthy plane in Mn) and insurance.  So it will be a bit yet before it flys, but for sure it's close.  JImChuk

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Posted

AnP left a bit ago, a few minor issues to address.  Will be good to by this evening most likely.  Still have to inform the FAA about the major changes, engine and propeller, plus state registration of a flying aircraft (no charge for unairworthy plane in Mn) and insurance.  So it will be a bit yet before it flys, but for sure it's close.  JImChuk

When I swapped engines from the Hirth to the HKS, FAA said it was not a major change or alteration and 5 hrs phase 1 was all that was required plus the logbook entry. I might have got lucky and they just didn't want to bother with me. I seem to have that effect on people!

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Posted

My understanding is they have to be notified of a major change in writing, and phase 1 flight time plus log book entry.  I think that is what it reads in the operating limits. If the plane was registered before something like 1990, and still has the old airworthiness certificate, other older  rules apply, and the FAA is required to make an actual inspection.  They then change the airworthiness  cert to a new one with the newer rules applying.  Last conditional inspection on your plane was it 2006 Allen.  Sure is a different plane today.  JImChuk

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Posted (edited)

EDIT: pasting didn't work the way I thought so added the snips from the op lims

This is from the "old old" style op lims (My project Kitfox Speedster)

This is from the "Old but not that old" style op lims (My Sonerai)

And this is from the "New" style op lims. (New limitations updated this year for my Yellow Kitfox IV)

 

 

In 2 cases the FAA is supposed to be notified of a major change and their response received. With the old old style the response must be in writing. In the new style it doesn't say it has to be in writing but you have to have concurrence. And then there is the in-between limitations that don't even say you have to notify them.

The bottom line is it depends on what YOUR op lims say. The safest course of action is to notify and get a response in writing or by e-mail. Having said that, I've made a lot of major mods to my Sonerai and never notified because the op lims didn't say to, but I did make log entries.

New.png

old but not that old.png

OLD OLD.png

Edited by 109jb

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Posted

I'll read the op limitations when I go back outside, but the FAA inspection had to be done on my first Avid Flyer when I changed engine from 532 to 582.  Second Avid hadn't finished it's Phase 1 flight testing, and they had to inspect for change of location flight test area.  In both cases the planes were issued updated airworthiness certs.  In both cases, the FAA inspectors came right to my house where I had the planes.   That was in 2005 and 2008.  JImChuk

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Posted

I'll read the op limitations when I go back outside, but the FAA inspection had to be done on my first Avid Flyer when I changed engine from 532 to 582.  Second Avid hadn't finished it's Phase 1 flight testing, and they had to inspect for change of location flight test area.  In both cases the planes were issued updated airworthiness certs.  In both cases, the FAA inspectors came right to my house where I had the planes.   That was in 2005 and 2008.  JImChuk

I just reviewed my limitations and since the engine was still resip and fixed pitch it is not considered a major change. I do like the new system of having the AW cert printed on the operating limitations. That way there isn't a chance of them getting separated. But as in the past, different inspectors in different areas have a different understanding of the regs and how they apply. Since I have never bought one from a different area, the limitations have always been pretty much the same.

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Posted

Well I took a look at the operating limitations for your old plane Allen,  and they are sure different then any I've seen before, and I've had the chance to study at least 8 different ones if I include the ones I mentioned in my last post that were redone.   The one in paragraph A 1  states. 

This aircraft shall be operated in accordance with FAR 91.319.   

A 2 says..   Any major change to this aircraft, as defined by FAR 21.93, invalidates the special airworthiness certificate issued for this aircraft.      (and nothing else)   Nowhere else in the limitations does it mention a change, minor or major.  

I sure wish I had read this before, and could have contacted the local FISDO to see how this can be resolved.  Reading FAR 21.93 does not seem to apply to the Kitfox, wonder how they interpret that regulation???   I'll call the FISDO on Monday morning to see it they can get onto it and get a solution in a reasonable amount of time.  Ya, I know that's asking a lot from a governmental agency, but I can hope, can't I??    These were not the original limitations, these were done in 1998, after the N number had been changed to the current number.  I usually get a copy of all the paperwork the FAA has on a plane I own, can't remember if I did that for this plane or not.  I'll have to look, not that it maters, unless these limitations were super seeded by a later set.   Nothing is ever easy..... :banghead:   JImChuk

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Posted

Still waiting on the FAA to return my calls.....:dunno:  Insurance company hasn't returned my call either.  JImChuk

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Posted

Still waiting for the FAA, but did get a video uploaded to utube today showing the plane.  Few bits and pieces still left to finish, glare shield not completely fastened, little stuff like that.  Anyway here you go.  JImChuk

https://www.youtube.com/watch?v=zWh5kq4ox60

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Posted


Very nice Jim hope you get to fly it before it starts snowing.

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Posted

FAA told me today to go fly.  I didn't argue.  Insurance company said I had to have 2 hrs dual with CFI in same make and model.  After some discussion, they said an EAA Flight Adviser program would do it as well.  I think I got that done in one phone call today.  He is about 90 miles away in Superior Wl.  He was surprised the insurance company gave me any grief at all considering what I have been flying.  He will send me a packet of info to help prepare me for the first flights.  Getting closer.... JImChuk

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Posted


think i would fly the model 4 to the local cfi and get your dual instruction.

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Posted (edited)

What insurance company are you dealing with?  I am either going with Avemco or thru the Ultralight assoc. I talked to my purposed instructor last night and he is booked up till late in the week. TW instructors are getting rare!

Edited by Allen Sutphin
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Posted

I've got Avemco insurance on the Avid now, and that is who I was dealing with for the Kitfox.   They quoted me $390 for liability only, $500,000 coverage.   He also told me that if I had 2 hrs. flying time by myself in it they would insure me.  JImChuk

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Posted

2 hours by yourself, that's a no-brainer!  It will take that long to get it tweaked the way you want it.

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Posted

Got an email from Avemco today in response to my email on Friday asking if they needed any information from the EAA Flight advisor, and that I had talked with him and he was sending me an info packet on setting up a first flight game plan.  They said they didn't need anything from him, and when did I want them to start the insurance.  I told them Wednesday, so it looks like I have crossed that hurdle as well.  Getting closer..... JImChuk

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Posted

Good news. Let the festivities begin!!! Be safe and let us know how things go.

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Posted (edited)

Well after bringing  it home in a 1500 mile trip, 6 years of on and off rebuilding, Kitfox 4  N# 423GB left the ground this evening for the first time since 2006.  When I got it, it had a Subaru EA81, and weighed 826 lbs.  Now it has a 80 HP Rotax 912, and weighs 645.   I just did a couple short trips around the pattern, but she sure flew nice, and climbed like a home sick angel.  Here are some quick numbers.  I'm at 1500 MSL, and wasn't pushing anything to get the most out of it.   I was off the ground in about 300', climbed at 1000' per minute, cruised at about 5000 rpm doing 90-95 MPH.  And that is without streamlining on the lift struts yet.  I'm sure the numbers will be better then.  I have some videos of the flights, but it will take some time to edit them into something I can put up on utube.  I snapped a couple of pics of my computer screen with the videos on so I could at least post some pictures.  One thing else I learned from the videos, is it took 38 seconds to get from pushing in the throttle to 500' AGL.  Best I think I've ever measured with my Jabiru powered Avid was 42 or 43 seconds.  I did it once in my Avid B model with 532 in 32 seconds, but that plane only weighed 445 lbs.  Anyway, I'm one happy guy this evening.  I'll have to start working on editing the videos soon.  I see I didn't get the date stamp set right on two out of three of the go pros.  JImChuk

Kitfox flight 1.jpg

Kitfox flight 2.jpg

Kitfox flying 3.jpg

Edited by 1avidflyer
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Posted


Hey wait to go Jim cant wait for the videos.

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