New to me Kitfox

[Xengineguy]

I have been lurking for a while,wanted to say hi and great forum!
A few months ago I purchased a kit fox speedster IV 1200 with a rotax 912.
80 hp. This kit was started in 1994, but little work completed in the years that passed.
The quality of the kit is very good! Very complete, lots of misc. you would normally have to buy as extras are included! (Safety wire,electrical connectors,hose and fittings etc.etc.)
Very much enjoying the build at this time. I'm sure I will have a few questions from time to time. First attempt at posting a picture?? Ready to start covering. Thanks again Mike

[SkyPirate]

looks good :) some things I would do before covering..decide where I'm going to put com antenna,..is there a plate already there or does one have to be installed,..are you using the standard antenna or the internal antenna that some use and mount in vertical stabilizer transponder antenna?

and welcome to the forum :)

[SkyPirate]

have you got the pieces I added in your photo that go from the door jam to tail?

[DesertFox4]

Welcome aboard Mike. The 4 with the 912 will be a great performing Kitfox. Build it light.;) I see a large baggage compartment and the wide body mod.
You'll enjoy both of those features.
Be mindful of old fuel lines that may have been included in that vintage kit.
There are many discussions on that subject to search for. Look for "mil. spec." black hose. Replace that with new alcohol proof fuel line. The mil spec. can swell internally and cause engine stoppage if using auto fuels with alcohol. Also some of the older fuel site gauges were known to become brittle and break which can leak fuel into the cockpit. That's an easy fix with the latest fuel site gauge kits offered by Kitfox Aircraft.

Be aware of aged liquid covering products. Some can still be used but others may not be useable anymore. Ask the forum for advice on specific items so you don't ruin your covering installation.

Also you can search Rotax sites for info. on your specific serial number on you engine for any safety bulletins that may or may not have been addressed.
You're probably aware of all the above mention items if you've been on the site for awhile.

Best of luck and have fun.

[Xengineguy]

Wow that was fast.
Yes Chase the comm plates are pre installed,I have the wood strips that go from the door jam to the tail.
Desertfox, I haven't used any hose from the original kit,and I agree completely about keeping it light! Just ordered new bunji coard material,and have new poly tak on the way. I was wondering about the other chemicals?? From what I've read they have a shelf life of at least 2 to 3 years. I hate to throw all this stuff away,but I don't want to be foolish? It's all 94 vintage.
I did use some of the spar varnish,was still good. The thinners I think would be ok?
Am aware of a few ADs on the engine, a few on the air frame also.
Have a question, my speedster kit uses 1/4" heim ends at the rudder pivot,did I read there is an up grade for this? Are 1/4" ok?

Thanks everyone. Mike

[Pilot4Life]

Mike,
Welcome to the forum and congrats on your Model 4-1200 score! I'm not building YET, but the response you just got from these folks is the "norm". Anything you've got questions about, someone here can answer...from Building Tips/Techniques to Regulations & Paperwork...This forum is great! Almost a "one-stop-shop" if you will! Welcome and please keep us update on your build. The "______'s Build" (i.e. Oz Build SS7 & Esser's Build) seems to be a good tool to keep things updated and address concerns or field questions. Until next time...

[cap01]

the sealant/adhesive for installing the wing tanks definitely has a shelf live . I'm aware of a late 90s speedster that has had both wing tanks loosen and start moving due to incorrect installation with crappy sealant . also consider installing the new improved wing tanks . it is expensive but much easier now than to have to cut the wing open and replace them later . I know , check my albums .
lots of info on this site , don't be afraid to ask

[cap01]

by the way , nice stand

[t j]

I built and fly a Model 4. The last generation and best of the original Kitfox;) in my opinion. I'm not aware of any upgrades to the 1/4 inch Heim on the rudder.

I hate all the plastic zip ties on my Kitfox. If I had it to do over I would not use them anywhere except to secure the seat pan as you will cut them off and replace once a year at annual anyhow.

I am slowly replacing all my zip ties with electrical wiring lacing cord.
http://www.aircraftspruce.com/catalog/elpages/BreydenLacingTapes.php

AC 43.13-1b and AC 43.13-2b shows you how and can be found on line but I find my hard copy is mush more handy and useable in the shop.
http://www.aircraftspruce.com/catalog/bvpages/asaInspectionRepair.php?clickkey=218417

[Xengineguy]

Great info as always,thanks guys. I am considering building aluminum
fuel tanks. I know some have failed in the past but I dont like the fiberglass ones that came with my kit (Kream coated).
Another question did any IVs come with a header tank only? If so what did the factory do to the wings to reinforce them? Drag, Anti drag bracing?

Has anyone used the plastic replacement tanks? Looked like you would loose
most of the original structure the fiberglass tanks provided?

If I build new tanks,I might incorporate a horizontal baffle "X" to provide some extra strength ?? Building metal tanks as light as glass tanks will be a challenge even W/O extra bracing inside. Need to keep the weight down.!!

Mike

[SkyPirate]

mike,..look into rolling your end seams instead of welding ,..if your putting a baffle in,.. there are a few ways you could attach it,,prior to forming your outer skin you could weld tabs that would hold the baffle in place and put a square hold where the tab could be folded thru the baffle to hold it in place and also limit expansion of the center section of the tank,..by doing this there is less chance of a leak because your flush welding the interior of the tank to a tab,,which will allow more flex on the baffle without stressing the baffle and weld joints,..ie from fuel sloshing back and forth putting side forces repeatedly,

get a good paste type sealer and put it on your end caps then roll a bead that forms the outer shell and end cap lip together,,this will allow the tank to twist but not leak and no welds to crack under stress,.. I'd use 3003 aluminum to make this,..if you have or know someone that has a French wheel it would make it allot easier to roll the seams,.. the skin I would overlap on the top in line with the filler port and do a folded seam with the same paste sealer in the joint the end caps and baffle would keep it from coming apart once installed..you could even solid rivet the over lap joint of the outer skin,.. and also solid rivet the tabs to hold the baffle,,with no welding at all

because of the area and weight of 13 gallons of fuel I'd use at least .020 thick aluminum or even .025

[t j]

Another question did any IVs come with a header tank only? If so what did the factory do to the wings to reinforce them? Drag, Anti drag bracing?



Yes and yes. Without the wing tank there is a drag, anti drag tube brace in those rib bays. There are drawings for all the wing with or with out tank combinations in your builder's manual.

[cap01]

my wings came with a 6 gal tank in each wing . the tanks fit between ribs . if there wasn't a tank installed , there would be drag/anti drag braces in that bay . the tanks will provide a part of the wing structure which a poly tank wouldn't do . I removed the 6 gal tanks and installed the large tanks that take up two bays . that required removing a rib and installing a shorter brace in the bay outboard of the tank .
I've seen pictures of a 9 gal poly tank mounted fwd of the instrument panel , I think with that the wing tanks were optional .

[SkyPirate]

something like this,..if I ever have a problem with my tanks this is what I will build

[avidflyer]

Hi Mike, I sent you a private message. Jim Chuk

[Xengineguy]

I have a couple sheets of 5052. I think it's .050. Was considering that, need to figure the weight . I have used it before with good results. I like to edge weld the ends,need the same "ribs" inside as a fiber tank. Maybe some sort of horizontal X also inside. To limit diagonal movement. Maybe just Stainless steel straps corner to corner inside the tank at mid height ? Still thinking about it. Thanks again for all the responses and ideas.
Mike

[Av8r3400]

This topic comes up every now and again. Aluminum tanks were tried on these planes in the early stages, then the idea was abandoned. They will crack and leak. This wing design is very flexible and this flexing will work harden the aluminum. Eventually leading to cracks and leaks.

Since you're still in the building stage, why not get the new updated tanks right from Kitfox. It is an easy instal at this point and they are designed to fit. No muss or fuss.

[SkyPirate]

I think it would work if no welding is involved, aluminum when it comes to welding is like any other multi component material, at the points of weld the heat burns off some of the properties which makes areas near the weld more brittle, steel you can add carbon even after its welded to replace what is burnt off in welding process, aluminum, although i have allot of experience welding it, im not sure there is a way to embed materials at welded joints after the fact, but no welding and rolled sealed seams with a seam sealer that retains its flex ,.. There is a good chance it would work

[Xengineguy]

Good points guys, I'm not committed to anything now. I might strip the inside of the original tanks and recoat with a better material, a product called "red coat" I use on a weekly basis and have for 20 years. (I build and repair/restore fuel tanks as part of my business).
As far as aluminum welding I too have some experience, it was my understanding that the rod alloy has a great deal of influence on the finished weld properties.
I also thought aluminum gets softer near the weld?? I would completely agree aluminum does fatigue when flexed and that's a problem!
Might just bite the bullet and get new tanks? Thanks for the input,not trying to be a pain. Mike. :)

[SkyPirate]

Your right Mike with the choice of wire/ rod used , almost all aluminum tanks I've welded were 3003 with exception to a few 6061 , if they cracked 99% of the time it was on a welded seam unless it was a puncture, not trying to be a pain either:) i was the road guy for Jones and Lamson, bryant grinder, and fellows gear shaper for awhile and also made Ravens dump body's and trailers for a while , most of the Ravens work was wire with exception to tanks, and built everything from nascar chassis to welding inkanel heat strips for asphalt heaters, not bragging, dont get me wrong:) i just think if the right process is used in building fuel tanks ,,it could be done and not have adverse effects

[SkyPirate]

Im really surprised that no one has built a fuel cell with the same concept as a nascar fuel cell:)