Welding and repairs used Kitfox

[PA-17]

I looked at a video on the Kifox web page and I saw a few seconds of the factory construction of the kitfox as they were putting one together. I was supprised to see they were mig welding the fuselage together or so it seemed. (It was not Oxy/Ac welded). Do they stress releive the fuselage after welding ? Is the fuselage especially the lower longerons oiled or not ?
If I were to buy a used kitfox requiring some tube replacement can I do that or does it have to be done by an A&P mechanic? How about recovering? Can I do that? I can check with PolyFiber and see if they have envelopes for the kitfox. But if not, can I get envelopes from Kitfox for the older models or do they just cover using a blanket method?
Just a few questions that I would like to have answered before I get involved with a project that will require a lot of that type of repair.

[SkyPirate]

how much damage does this kitfox have? there is more to it then just replacing a tube here and there if the fuselage has excessive damage,..
and the wings? what kind of shape are they in?

Chase

[Av8r3400]

I looked at a video on the Kifox web page and I saw a few seconds of the factory construction of the kitfox as they were putting one together. I was supprised to see they were mig welding the fuselage together or so it seemed. (It was not Oxy/Ac welded). Do they stress releive the fuselage after welding ?

MIG welding is the norm. No they are not stress relieved.



Is the fuselage especially the lower longerons oiled or not ? No



If I were to buy a used kitfox requiring some tube replacement can I do that or does it have to be done by an A&P mechanic?
As the owner of an experimental aircraft you can do any repair, modification or maintenance you wish. You will need an A&P do the condition inspection (similar to an annual on a certified plane) for an amateur built experimental.



How about recovering? Can I do that? I can check with PolyFiber and see if they have envelopes for the kitfox. But if not, can I get envelopes from Kitfox for the older models or do they just cover using a blanket method? You can do any of the covering or cover repairs. The blanket method is what is used on these. I know of no envelopes available. The blanket method is easier, anyway.

[SkyPirate]

If you opt to purchase this plane and repair it,..using a mig welder ..just preheat the joints first,..this will ensure that you don't get a cold weld and use a telescoping tube on the inside of the repair joint . use a 75/25 mix with .030 wire or a tri mix with 2 to 11% helium.
the best way would be to tig weld it,..no perocity in the welds this way,..no perocity means less distortion end result ,less shrinking ,..
with a mig,.. look at the tube like a clock,..weld from 4 oclock to 8 oclock first then 12 to 4 and 12 to 8,.welding the bottom first keeps the heat in the tubing for better welds.
I'm curious how much damage is done first,..if the fuselage is out of square then you must square all crucial points first prior to any welding new tubes in.

Chase

[PA-17]

Av8r3400:
It is good to know that the repairs can be done by the owner,including recover. I was not sure about that part. I did know that the original builder had the right to repair and inspect the aircraft but that was the end of my knowledge on the subject.Thanks for that information.

[SkyPirate]

If this is a rust issue,.and not damage due to a wreck.I'd drill every tube that concerned me and check the thickness of the tubing wall at the bottom of the tube or where water might have been trapped. you can weld the holes after checking the tube.

Chase

[PA-17]

Chase:
Plane not wrecked as far as I know. But it has been stored outside and looks like it. I would guess some tubing may be rusty. Bottom of rudder looks discolored in the photos. If the mice have not made it their home the tubing and spars may be all right. The price seems to good to be true and you know what they say about that.

[Lion8]

Chase, Good idea about drilling 'small' holes in the bottom of selected tubes, then rewelding.
Question: Do you guys ever use a back purge? How about filling up all the tubes with n2, co2 or argon, then welding to trap the gas inside? Sound like to much? - Lion8

[SkyPirate]

Tom ,,I have done that with argon and I'm doing that now on the plane I'm building ,..Argon works best,. because I had planned on this I drilled every connection point prior to welding so all the tubes would be exposed to a charge,.at the nose of the fuselage will be an inject point at the tail a purge point,..to each his own as to do this or not,..I also do it on the strut tubes.

P-17 if you plan on blasting the fuselage,..use the silycon bead blasting material,..don't use sand or high carbon based blasting materials,.. because 4130 is a low carbon material other then silycon blasting beads will eat the material away quick if held in one spot too long,.also carbon based sand blasting materials will put a slight magnetism to the fuselage which will raise havoc with your compass once your to that point .

Chase

[PA-17]

Chase:
What documents should I get from the seller besides the Bill of Sale and the 2 log books?
Is the operations and limitations a required document or can I get it from the group for the make and model I am considering?

[SkyPirate]

you will need to get a new AWC after your all done with repairs but the old one would be good document to have,..I'd get all of the paper work available first ,..then go from there,..I'm sure from what you have said about the planes condition that the present owners have not kept the paper work in order as well,..if your missing anything ,..you should ask the owners which office they used when they first did all the paper work ,..contact them for missing documents ,..they have an archive and should be able to get you what you need ,..just saves allot of guess work knowing which office was used. if it was actually registered.
Your basically going to have to look at this as a new first time rigistration ,..it might be required that you do a new phase 1,...especially if major reconstruction is involved,..any original phase 1 documents,..a big plus if available,..the original pilots log book if an airframe log book isn't available,. should have this and possibly a copy could be aquired of the times and fly test's done,..have you got the serial number from the present owner? you can do a quick back ground check on the serial number or tail number if it was previously registered.
I recently helped someone on the forum that had similar issues ,.. he has got it all in order now,..even though allot is said about the FAA in a negative way,..the offices are more then willing to help with previous owned/registered aircraft to get all in order concerning documentation ..it also makes their jobs easier getting it right.

Chase

[kitfoxnick]

I am not an expert but why would this require a new
AWC. Most operating limitations require contact a FSDO for a phase 1 if incorporating a Major change not a major repair. If the plane has a valid AWC and operating limitations woudn't you just need to make a log book entry and a new weight and balance. Then have an A & P do a condition inspection. Please enlighten me as I'm a newbie.

[SkyPirate]

I'm no expert either Nick ,..best to prepare for the worst ,..


an example ,..here in MO ,..the DAR charged a friend $500.00 to come do his thing ,..I never heard of this in NH ,..it was always free.
Glad I know this now though since I'm getting closer to DAR time.

Chase

[SkyPirate]

your more then welcome P-17 ,..glad I could help,..I know your excitement
I'm building a plane ,..my own design this time, a 4 place tail dragger,.. can't wait to get her in the air
still got some time before the paperwork end hits me, although I do have a reserved N number. and went thru a similar situation that your facing once ,.it's really not all that bad to get it right,..just takes a little time ,..which you'll have during the repair process,..just don't do the final registration until you 3 months or so from flying,..no sense on paying tax on a bird that's not flying yet. (if your state has a tax on aircraft) I've learned that MO does. NH does not . don't know about other states yet

[kitfoxnick]

Yeah Chase around here it used to be the fsdo job to do it for free. Now they don't want to touch it. You have to get a DAR.

The reason I posted earlier is why do more than you have to. If the plane has a N number, and AWC and log books why go through the whole process again and fly 40 hrs off. To me it seems simpler to just make a log book entry do a W&B and get a condition inspection. Now all this assumes your not doing a major change ie. same engine same prop. Just my $0.02

[SkyPirate]

agreed Nick,..don't do it if you don't have to,..unless major changes are done and it's required. I'm all for the less paper work the better ,..the less the authorities know the better too hence my nickname ..skypirate

[t j]

PA-17, I sense a little bit of confusion creeping in on the operation limitations. Operating limitations are issued as part of the Airworthiness Certificate and must be kept in the aircraft with the Airworthiness certificate.

The operating limitations do vary from inspector to inspector. Each FSDO has a different intrepretation of what needs to be included in the operating limitations and each inspector...FSDO employee or DAR...has a different interpretation of his/her FSDO's interpretation.

Most importantly, the operating Limitations spell out specifically what the owner must do when making changes to that particular aircraft. Some require written notification to the FSDO and some do not.

If the owner of the aircraft does not have the operating limitations I would get the FSDO on board with me on getting a copy of them before purchasing.

[Rodney]

Most sources recommend an ER80S-D2 or
ER70S-2 wire for MIG welding 4130.

I know it's going to be time consuming, but I am seriously thinking of drilling a very small hole in each tube of the fuselage, and injecting a thinned boiled linseed oil to prevent internal corrosion.

Regards
Rodney

[PA-17]

To: All:
I guess after all your help and my questions to the owner he thinks he has anothe local buyer. I suspect he was not able to come up with the airframe log book. I don't know if that should be a deal breaker or not but I told him it was. Without the log you just don't know if any service bulletines have been complied with and you don't know if the airframe has been damaged in the past. If I am wrong let me know. It is a downer after all the exchanges with the owner,especially since he contacted me. There is another one in my area but the owner just never returned any of my calls. That is a early model no 2 and it is starting to go to pot also but it is in a tee hangar and looks better. Oh well back to the drawing board. I would like to thank everyone that took the time to answer all my questions. I do appreciate your input. Maybe I will find another at a good price. As I said earlier. If it sounds to good to be true it usually is.

Thanks :o

[SkyPirate]

Nick ..going thru the paper work concerning my latest build I found this,..
good to know concerning an AWC in reference to
8130.2F CHG 3


(2) In some cases, amateur-built aircraft are sold with an expired airworthiness certificate
or foreign airworthiness certificate. In such cases, an applicant may request and receive a special
airworthiness certificate for the purpose of operating amateur-built aircraft, only if the aircraft
previously was certificated in this category. In this case, a new Form 8130-7 would be issued along with
new operating limitations, but without the eligibility to obtain a repairman certificate for that aircraft.
The new certificate should only be issued after the FAA has verified airworthiness by following the
appropriate procedures in paragraph 88 of this order.

Chase

[fred colman]

Hi Skypirate,while on the welding subject,how is your project coming along.How about some photos.

[SkyPirate]

Hi Fred ,.it's coming along pretty good ..if you'd like to se some photo's send me an e mail to chase001@centurytel.net
I'll send you some ofthe latest


Chase