Javron Cub Building for Dummies

[Sam D]

Index to main posts in this thread:
Background and order This post
Javron builder assist Post #2
Kit delivery and inventory Post #11
Trim plate and fuel value plate Post #23
Floorboards 1/2 Post #31
Floorboards 2/2 (front) Post #33
Metal Headliner Post #47
False boot and boot cowl Post #52
Wing tip light bases Post #56
Nutplates and piper channel Post #57
ELT Installation Post #60
Interior Panels Post #62
Fitting windshield Post #63
Fitting wings Part 1 Post #68
Fitting wings Part 2 -Wing Root Fairings Post #71
Under-seat bulkhead Post #72


After reading threads about folks building their own planes and seemingly doing everything short of forging their own steel, I’ve jumped in to the build process. I’m not totally kidding about the “Dummies” part. Until pretty recently, I couldn’t tell the shop head of a rivet from...well…whatever you call the other end. So, while I’ve gained a lot of knowledge by reading of others’ builds (I think I’m personally responsible for 900K of the 1M views of Bill Rusk’s thread), I wasn’t sure if I could add anything here. But I’m guessing there might be others like me who are more at the beginner end and might benefit from some of the basics I’ll be struggling with as well as my mistakes along the way.

About me and (lack of) past experience
I’ve been flying since 2005. Almost all of my hours are in a 1976 Piper Lance.
Unlike a lot of stories I see here, I didn’t spend any time building models or playing with RC aircraft as a kid. I think I’ve “built” one model plane. I say “built” because I basically glued the wings from one model plane onto the fuselage of a Viper from Battlestar Gallactica (but I did it as a canard so maybe that gets me some homebuilding cred!)
My brother is more of a builder but mainly woodworking and sailboats. So I might have a recessive building gene somewhere hidden away.

Getting (somewhat) educated
Realizing that I’m starting from square one, I’ve done a few things to educate myself while I set aside funds for the build. These included:

• Registered on supercub.org (wow, almost 5 years ago. Perhaps I set a new lurker record)
• Subscribed to Kitplanes and joined EAA
• Read numerous build threads multiple times including the grand daddy
• Read a few homebuilding books
• Visited a completed Javron cub somewhat local to me
• Attended an EAA Sportair sheetmetal workshop – I figured this was the first medium I was going to be working in
• Purchased Northland drawings and later discovered Christian Sturm’s excellent site
• Visit Javron at Oshkosh (2015 and 2017) and also had a phone conversation with Jay about the process and asked about: 1) whether the kit had been evaluated by the FAA and was on their list (it’s not but plan to sometime in the future); 2) whether there is a build manual (there is not but there is a “builder assist” offering – see below)
• Finally, I got a tailwheel endorsement in PA-12

What I’m building (and some why’s):

• Standard width Super Cub. Standard width because I like the idea of “wearing” the plane. I might make gone wider because it’s a popular option but re-sale is not a concern to me.
• Round wing tips, round air box – I like the looks
• Manual trim – in 700+ hours of flying the Lance, I have never used the electric trim. I agonized over this one quite a bit. We’ll see if I regret it…
• O-360 engine fixed prop – basically trying to keep things as simple as possible
• Float fittings – I like to have options!
• Acme struts (although I worry that I might be on of “those guys” with a nice SUV that has never been on the dirt!)
• When in doubt, I went with the original design, such as:
  • Trim on side panel
  • Aluminum panels
  • Wood floor boards
  • Single door
• Large lower baggage door – didn’t realize that the big door extends forward into the passenger area. Not sure I would go for this if I had to order again. Not a big deal either way.
• The only decision I made (by default) that I would probably have changed was that I didn’t specify that I wanted the extra/diagonal cross bar on the front of the fuselage. My mistake – I incorrectly assumed this was standard on the Javron. It’s not and is called out as such on the order sheet.
• I placed the order in October of 2018 and the kit was ready in May 2019. No idea if this is typical/atypical, and I didn’t push for speed. Just the time it took.

 

[Sam D]

Builder Assist Program at Javron
I spent a week in Brainerd, MN at the end of May getting rolling on the build under the watchful eye of Jay DeRosier. I was considering bringing along someone to work with me. Afterwards, I was glad I didn’t because it was enough for me to figure out what was going on let alone coordinating with someone else.
I flew in to Minneapolis on a Sunday, rented car, and drove up to Brainerd where I stayed at Days Inn in nearby Baxter. Right behind the hotel was Paul Bunyan State Trail which was great for morning runs.
We worked Monday to Friday each day from 8 am to 7-8 pm. Jay could have gone longer but I was cooked by then and was at risk of fouling things up. I drove make to Minneapolis and flew home on Saturday.
Here’s what we accomplished in the week (which was about average according to Jay):

• Installed fuel lines – really nice to have 3-4 other planes nearby in various states of assembly to learn from
• Installed brake lines on gear legs
• Fitted aluminum panels
• Fitted and attached stringers
• Fitted tail feathers and installed related control cables
• Fitted torque tube (this took a surprising amount of time to shim properly)
• Riveted seat pans to seat frame

While a lot of work and long days, this was a really fun week. It was great to see the operation and meet people manufacturing the kits. I work at a desk in my day job – so it was really neat to do this type of work.
Aside from the progress, another big benefit of the week was doing what I call learning ‘disciplines’ of building, such as: a) pace of progress (how things just take a while – be patient); b) pull it out, put it back in (I think I installed the torque tube about 20 times); and c) techniques – Jay taught me a lot of building techniques. Some more subtle than others, including proper way to bend cotter pins, cutting sheet metal, using a punch to pilot holes and many others that I can’t remember now but really hope come back to me at the right time!

Mistake: take a look at the following picture and see if you notice anything headed in the wrong direction:



The aluminum seatback is positioned backward on the seat frame. After this picture, I did a fantastic job of riveting it on to the frame only to realize that I had to drill out all the rivets, turn it around and rivet it back on. (Later, I was touring all of Javron’s parts including seat frames and seat backs. I couldn’t help but think how easy it would have been to just grab a new part… J)

A few final thoughts:
If I had to mention one downside of builder assist, it’s that there’s less need to think things through (e.g. need to install a nutplate? here’s the correct nutplate, and the correct drill bit size, the proper rivets and the squeezer…). Sometimes the puzzling about things is what leads to the development.
Make sure you have a backlog of things to do. It was not uncommon for Jay to get called away for a phone call or some other manner. While this was only 10-15 mins at a time, it was good to have something else to work on and not be dead in the water on something.
I can comfortably say that the week I spent saved me months of work and gave me a lot of confidence to take things on my own.

Here's the fuselage in Jay's shop. Just to give you an idea of his attention to detail...those sawhorses have felt on the bottom of their legs!

 

[DENNY]

If you have a underseat battery you are going to want to hinge the bottom seat cover. The first time you have to put anything big in the back you will fall in love with that big door!!! One of the best mods going.
DENNY

 

[bob turner]

I have flown Cubs with engines from 50 to 180 hp. Aside from fuel cost, the 160 is my favorite. The 180 will haul you straight up, but it is just enough heavier that your nimble Cub becomes a station wagon.

 

[Sam D]

You did see the part where I fly a Lance right? ;-) I know station wagons!

 

[cubdriver2]

I have flown Cubs with engines from 50 to 180 hp. Aside from fuel cost, the 160 is my favorite. The 180 will haul you straight up, but it is just enough heavier that your nimble Cub becomes a station wagon.

Bob, this is only noticed by lower powered E2,J2 and J3 pilots. The rest of the pilot population has no idea what " lite" really means. 558lb 37hp E2 Cub is still the best Cub ride I've ever had

Glenn

 

[supercrow]

Bob, this is only noticed by lower powered E2,J2 and J3 pilots. The rest of the pilot population has no idea what " lite" really means. 558lb 37hp E2 Cub is still the best Cub ride I've ever had

Glenn

My first J-3 was a very light 39' with an 85 stroker and I haven't flown anything since that I thought felt as "right".

 

[sj]

Sam, be assured you have not set the all time lurker record... not by a long shot! 8)

Thanks for posting about your project!

sj

 

[Steve Pierce]

Thanks for your post. I can relate to your seat pan and other experiences. I'd like to know how many times these things go together and back apart before the final assembly. Can't wait to hear more.

 

[Sam D]

Thanks for your post. I can relate to your seat pan and other experiences. I'd like to know how many times these things go together and back apart before the final assembly. Can't wait to hear more.

Thanks Steve (and everyone else) for the warm welcome. Your thread on the cub with all the problems has been a good gauge of my learning development. After my time in Brainerd, it made a whole lot more sense to me!

 

[Sam D]

Getting it home and first steps

I used a shipper recommended by Jay which worked out really well. For some reason, your local cable company can only give you a four hour window, but this guy was able to drive from Minnesota to northern California and arrive within minutes of his estimated time!
First, he helped me unload everything from the truck onto driveway


And then we moved everything into the garage.
My first order of business was to inventory everything. One tip that may be helpful to others is that I labelled all of the boxes with letters and then noted on the inventory sheet in which box each item was located.
Honestly this was my first (probably of many) experience with being overwhelmed. I’d come across a part that I couldn’t identify, put it aside, come across another part I couldn’t identify, etc etc. This is when it would come time to take a break, come back to the task and slow down. At the end of the day, I think I got just about everything identified properly (note: rear stabilizer pivot looks a whole lot like the flap handle pivot! :smile
Before I left Brainerd, I put together a rough action plan as follows. Jay mentioned that, from his auto background, you'd put the whole car together first then take it apart, paint it and then to final assembly. Rather than covering sooner, I think this approach makes sense for me because it might minimize those "oh shoot why didn't I make room for xyz" moments
- fit floorboards
- fit boot cowl
- fit windshield
- put wings on
- run cables
- wing root fairings
- engine and cowling
- cover and paint
- final assembly (small stuff like engine and avionics)

 

[DENNY]

I would consider hanging the engine or a 300 lb box on the motor mount as step number 1 before you drill any holes in anything. Put the wings on and set washout and check inboard flap clearance before I fit the windshield. Once the boot cowl and false boot cowl is on fit you dash and all the interments while sitting in the seat. If for any reason you have to lay on your back under the dash reconsider you design. Run and secure all wires in wings and back of fuselage before you cover (thinking of how you will access them once covered) I think the engine weight will flex the fuselage enough that some stuff might not line up quite right. A simple box full of sand bags will do the job and easy to take on and off with engine lift. Nothing worse then trying to avoid hanger rash on fresh paint then climbing in and out 100 times try to make a dash and avionics fit. No right or wrong just some things to think about.
DENNY

 

[Gordon Misch]

I'm beginning the build on an EAB 12. I'm thinking that a broad-brush sequence will be flight surfaces fully rigged, including control cables, then plumbing, then electrical including panel with FWF wires left long, then FWF. Entire plane completely assembled, maybe even taxi test, before cover.

Others' thoughts very much appreciated. Once I get really rolling on it this fall I should probably start a thread. No doubt I'll have lots of questions even having done a thorough rebuild on my cert 12.

 

[Eddie Foy]

What was the cost of the kit?

 

[tempdoug]

What was the cost of the kit?

call jay and ask him.

 

[Bill Rusk]

Awesome thread Sam. Thank you for posting. Please keep it going.

Bill

 

[RVBottomly]

What was the cost of the kit?

His website posts information on that:

https://www.javronaviation.com/content/docs/SuperCubKitOrderFormRev.pdf

 

[RVBottomly]

I'll echo Bill. Thanks for posting and keep sending us pictures! I'm blown away with how nice your wings and fuselage look. I'll be following for sure.

Vic

 

[Steve Pierce]

I would consider hanging the engine or a 300 lb box on the motor mount as step number 1 before you drill any holes in anything.

When we rebuilt my Dad's Clipper fuselage I built new doors and door sheet metal. I thought I would be smart and tighten up the tolerences a bit. Ha, that bit me in the butt. Put the engine on and quess what? Doors didn't fit. Later noticed new Bonanzas come down the line with a big weight installed as they come down the line prior to engione install.

 

[bob turner]

I love that Dennyism: Don’t do anything that will later force you to lay on your back under an instrument panel. Ditto wing root wiring - make it so you can unscrew the panel, then easily replace a switch.

I envy you guys - brand new stuff!

 

[N86250]

When my mentor was assembling a Cuby for the first time in his two car garage, it wasn't going to fit with the engine on it. So the engine was left on the engine hoist and pushed into a corner. Then we pinned the right wing and pinned its struts. Kerflop. The right wing tip went to the floor. Without the weight of the engine on the fuselage she wouldn't hold up just one wing. Be ready for little surprises like that. It was a private joke for many years that Henry ground looped a Cub in his garage.

 

[mike mcs repair]

When my mentor was assembling a Cuby for the first time in his two car garage, it wasn't going to fit with the engine on it. So the engine was left on the engine hoist and pushed into a corner. Then we pinned the right wing and pinned its struts. Kerflop. The right wing tip went to the floor. Without the weight of the engine on the fuselage she wouldn't hold up just one wing. Be ready for little surprises like that. It was a private joke for many years that Henry ground looped a Cub in his garage.

been there, learned that in 1993.....

 

[Sam D]

Trim plate and fuel valve plate
Happy Friday. I’ve been working on fitting the interior panels and the floorboards and will post on those later. But here’s a little work on the trim plate and fuel valve plate.
The left interior panel covers the fuel valve and the trim handle and indicator (if you have standard trim as I do). Both of these items require cover plates with indicator markings.There are plans for both of these items on the Northland flash drive (you can get it on this site) and on supercubproject.com. Just don’t search for “trim” as I did. Piper calls it a Stabilizer Indicator Cover (#10936). The fuel valve plate is #12838. I ended up departing slightly from the standard plans for both of these as follows:

Fuel valve plate – The plate in the drawing is 7” wide x 5.5” tall. On my kit, this would put the plate overlapping an edge on the interior panels. For aesthetics, I modified the dimensions to be more of a square.
Stabilizer Indicator plate – This one was a bit more tricky. I noticed that the distance between the center of the trim crank and the trim indicator slot looked closer together than on my plane. Sure enough, if you look at drawing #12999, you can see that the indicator assembly is shown as coming straight off the tab and remaining horizontal. Further, that distance, as shown in the indicator cover plate drawing is about 2”. This same distance on my plane is more like 2.5”. Therefore, if I were to follow the Piper drawings, the cover plate would pull down the trim indicator placing stress on the indicator slot. When I was in Brainerd, Jay pulled out a sample Indicator plate which I traced and photographed (see photo below with dreaded torque tube shims in the background). I ended up following these dimensions for my project.​

​

Tools/Materials:
Just in case this is useful to someone, here is an exhaustive list of everything I used. This list will (hopefully) get shorter with future mini-projects.

Aluminum sheet: The Piper plans call for: 3S-1/2 H Aluminum .020 thick to be used for the plate. According to Aircraft Spruce (https://www.aircraftspruce.com/catalog/mepages/aluminfo.php), 3S is an old designation which has been replaced by 3003. In addition, ½ H is now H14. So, if you order 3003H-14 .020, you should be good. Actually, the plans call for .032 thickness for the fuel valve plate but I used .020 for both.
​

Snips: Used to cut the aluminum. I got a left and right version of these from Aircraft Spruce . Be patient when cutting and plan on sneaking up on your eventual mark in a few passes.
​

File: Purchased from Amazon. I use these all the time.
​

Center punch – Purchased from Amazon
​

Step drill – Purchased from Amazon
​

Calipers – Purchased from Amazon I’ve got to say a few things about calipers. Before this project, I didn’t own any. But I find I use them ALL the time (how big is that screw? What size drill bit do I need for that hole? Is this really the center line? How can I make a row of rivets consistently ½” from the edge of this panel? Etc, etc). They're cheap and extremely useful.
​

Deburring tool – Purchased from Aircraft Spruce
​

Nibbler – Purchased from Amazon
​

Process – I used some drafting tools (t-square, ruler, circle template, fine tip sharpie) to draw out the two covers as depicted in the plans with the slight changes I noted above. I then cut out the plates using the snips in a few passes as noted above. After cutting them out, I used the file to leave smooth edges. Using the center punch, I marked the spots for the screw holes, drilled them out and deburred the holes. (Is it just me or is deburring oddly satisfying?) I then drilled out the center holes using the step drill. Finally, for the slot on the trim indicator panel, I drilled holes at either end of the slot and used a needle file to file down the center line of the slot. I then used a slightly larger file to enlarge the slot to my pre-drawn dimensions (see Piper plans). I still need to figure out how to put a slight bend on the edges (I’m guessing this involves working with a “break”…which I’m hoping is a misnomer). And I think I might round off the corners a bit more.


For the interior panel, I used the nibbler to cut out a couple of rectangles smaller than the plate size to give me quick access to the fuel valve and trim panel if needed. I’m not sure this is needed since I plan to have my panels removable after cover. At any rate, I positioned the plates to be parallel with the top of the panel and match-drilled the screw holes.
Finishing
I’m planning on having both of these parts powder coated to match exterior paint color and will use AeroGraphics for the markings.

Hope this is helpful to someone,
Sam "this is my first rodeo" D

 

[RVBottomly]

​

​

I still need to figure out how to put a slight bend on the edges (I’m guessing this involves working with a “break”…which I’m hoping is a misnomer). And I think I might round off the corners a bit more.
​

Bending brake. (Usually doesn't break things).

Harbor Freight has a rudimentary one that works on 18 gauge steel and even thicker aluminum. C-Clamps hold things down.

I've used one for bending the ribs for the tail feathers. Lots of similar ones online.

https://www.harborfreight.com/30-inch-bending-brake-67240.html

Vic

 

[skywagon8a]

Bending brake. (Usually doesn't break things).

Harbor Freight has a rudimentary one that works on 18 gauge steel and even thicker aluminum. C-Clamps hold things down.

I've used one for bending the ribs for the tail feathers. Lots of similar ones online.

https://www.harborfreight.com/30-inch-bending-brake-67240.html

Vic

Be cautious when using a brake, be certain that you make provisions for the correct bend radius. If it is insufficient, the aluminum will crack ruining your part. Most cheap brakes have a sharp angled blade which will work for some junk steel parts but certainly nothing you would want on your plane. Make yourself some radius strips to go between your part and the blade. Set up your brake correctly. The setup differs for different thicknesses of metal.

 

[CamTom12]

Bending brake. (Usually doesn't break things).

Harbor Freight has a rudimentary one that works on 18 gauge steel and even thicker aluminum. C-Clamps hold things down.

I've used one for bending the ribs for the tail feathers. Lots of similar ones online.

https://www.harborfreight.com/30-inch-bending-brake-67240.html

Vic

I used that same model when I made my new baffle sections and oil cooler plenum. It’s a good tool, but approach your bends slowly so you don’t overshoot.

 

[StuBob]

Forgive this stupid question but, how do you know what order to do things in without a manual?

 

[Steve Pierce]

If you don't have a brake you can get this Malco tool at Lowe's or Home Depot around the ducting. Works well on small stuff.

 

[Sam D]

Forgive this stupid question but, how do you know what order to do things in without a manual?

This is not a stupid question at all. It’s a question I had and continue to have - and one of the reasons for this thread. And it’s kind of part of the fun figuring it out. In my mind, I’m basically working toward the big milestone of covering which is the main point of no return. Certain tasks can be done without regard to a particular order (e.g. I need to install some nut plates for future water rudders, but it doesn’t matter when I do it before covering). Other tasks require a sequence (e.g. fit floorboards before installing rudder pedals). So, I use: 1. The backcountry build manual, 2. Others’ write-ups, and 3. My own “puzzling through it”. I do expect that I’m going to have at least one “oh crap, I should have done x” moment - hopefully it’s not a big one.

 

[Fortysix12]

Think in terms of systems,groups. Much like the piper supercub parts manual