Chuck and Ryan's Carbon Cub Build Blog

[Chuck]

Scott and Lynn

The plane is sold by CC as a FAA certificated plane as well as a kit. The kit uses the exact same components as the certificated plane. CC does not prime the wing structure, although if it will be used on floats in a salt water environment it is recommended. Since my objective is to build it the same as a factory built plane, I opted not to prime the aluminum.

I have yet to find any steel components (other than bolts). There were two brackets made from stainless, but everything is aluminum.

 

[Chuck]

Great quality on those parts, and have I missed something, er, like the XK motor?

You have a sharp eye.

Yes, that is a 4.2 Jag with side draft Webers hoping to some day find a home in a D Type replica.

 

[Jack]

Very nice Chuck!

 

[Chuck]

Drag Tubes

The second wing is underway. A few posts of some details will follow.

The compression tubes need to slide in and out of the fittings and they must seat fully. If they fail to seat properly, the inner surface of the fitting and / or the end of the tube needs to be ‘polished’. A red Scotch Brite pad works well

If there is any doubt about whether a tube is seating fully, measure the depth of the fitting and then place a corresponding mark on the tube. This will provide a visual reference which will confirm a properly seated tube.

Once the tubes are all in place and the wing assembly is resting on the saw horses, we slid a center rib in and out adjacent to the compression tubes. It should be snug. Also check the measurements from spar to spar at each compression tube location. They should be exactly the same.

After the tubes are in place the fittings are riveted. It may be over kill, but a short piece of masking tape protects the spar from scratches when setting the squeeze riveter in place

 

[Chuck]

Wings are Done!


Have not been posting about the progress on the airplane on this forum since it is a bit off topic for a GT40 forum. But a progress report is in order. Details are on the SuperCub.com forum.

Moving the wings from the saw horses to a stand for storage is a bit like a right of passage. Sort of like graduating from eighth grade or learning to drive a stick shift. A milestone marking the end of a phase and now time to move on to something else. So after 150 hours spread over two months we can announce that the WINGS ARE DONE!

Picture of a fellow builder holding up the wing was taken when we weighed it sans fuel tank, flaps and ailerons. Weighed less than 60 pounds, exceptionally light for such a structure.

Now on to the fuselage which should be fun, and much less repetitious than all those ribs!

 

[Will Campbell]

Lovely stuff. Almost looks like what RCR would supply if they were in the business of Cub reps...

 

[Jack]

Well done! First milestone achieved.

 

[Al Jones]

Wings are Done!




Now on to the fuselage which should be fun, and much less repetitious than all those ribs!

Know what you mean......On a smaller scale with the R/C's but no less repetitious, I always liked building the fuselage more and was happy when done with the wings. I think we've all been waiting for updates and it's a wings/wheels subforum so keep posting!

 

[Ron Earp]

Watching this thread with interest. Still planning on a 180hp plant? I flew a cub many years ago when doing my PP but it certainly didn't have much power. 2000 fpm would be a blast.

 

[Chuck]

The Cup Holder

Thanks for the feed back AJ, P-Nut, Molleur and Ron. I will start posting a few more details as the project progresses.

Recall it was Cub Crafters announcement last November that the 2014 model would include a cup holder which was the final impetus that prompted the placement of our order.

Unfortunately the announcement did not include a picture. One had to buy the plane to see what it would look like.

So I am now revealing publicly for the first time on the internet a full color image of the elusive cub holder.

It is truly a work of art. The panel glistens with that marvelous carbon fiber pattern. The cup holder has the right size and shape to accommodate an average size beverage.

And what a surprise: a VHF radio fits perfectly in that spot!

Once word gets out about this addition to the CC for 2014, Cub Crafters will be deluged with orders, I am sure.

 

[Will Campbell]

The Cup Holder

Thanks for the feed back AJ, P-Nut, Molleur and Ron. I will start posting a few more details as the project progresses.

Recall it was Cub Crafters announcement last November that the 2014 model would include a cup holder which was the final impetus that prompted the placement of our order.

Unfortunately the announcement did not include a picture. One had to buy the plane to see what it would look like.

So I am now revealing publicly for the first time on the internet a full color image of the elusive cub holder.

It is truly a work of art. The panel glistens with that marvelous carbon fiber pattern. The cup holder has the right size and shape to accommodate an average size beverage.

And what a surprise: a VHF radio fits perfectly in that spot!

Once word gets out about this addition to the CC for 2014, Cub Crafters will be deluged with orders, I am sure.

But Dad, it's carbon!

 

[Al Jones]

A-1 on the cupholder Chuck ! Even my 740i didn't have one.....frustrating with no place to put that morning cup-a-joe.

 

[Chuck]

Fuel Line Leak Test

Making really good progress on the fuselage. The fuel line installation is near the finish line before the covering process. But got a question.

The idea that a fuel leak would pop up when the tanks were first filled crossed my mind as I was installing the fuel lines. Ironically about the time I had the fuel lines in place, I learned that the on line manual had been supplemented with a section on this very topic. The Cubcrafter’s approach involves pressuring the system and using soapy water to check each fitting for tell-tale bubbles.

I pursued a bit less messy approach.

1. The forward and aft drain lines were plugged. The aft with a radiator bleed valve, which fit perfectly; the front with a piece of 3/8” hose and a bolt.

2. Four balloons were attached to the lines that attach to the fuel lines. These are cheap Wal Mart party balloons which hold air for a day or so. Electrical tape assured an air tight connection.

3. The air compressor was hooked up to the line that connects the gasolator to the fuel switch.

Then the fun part. Pull the trigger on the air compressor and watch the balloons fill up! They were not all the same size, but they did all fill up. I come back in 18 hours and see they were still filled. So I should not have any leaks.


I like this approach because:

1. You don’t have to worry about over compressing the lines. A balloon will burst long before the lines will.

2. No drippy soapy water to deal with.

3. No chance of missing a tiny leak with said soapy water

4. Adds a party atmosphere to a mundane work shop.

So here is the question: Is this a reliable way to confirm the integrity of the fuel system???

 

[Scott Calabro]

I'd say you'd complied with at least the spirit of things! It's not certificated so really do what you think is best.

 

[Jack]

I would comply with the build manual instructions. Soapy water is the traditional method, you can not visually detect leaking air from balloons even though they appear to be the same size as when testing started. Interesting in theory though.
Why take a chance?

 

[Bill Musarra]

How about soapy water to the outside of all the fittings, like we search for leaks in a tire? If you have fuel pumps, then i would think you need to get the lines up to that pressure and then test. Not knowing anything about airplanes, I may be out in left field without a parachute??:laugh::laugh:

Bill

 

[Chuck]

Now at 24 hours since inflated and balloons same size.

Bill, it is a gravity feed, high wing. No fuel pump. So very low pressure.

I may just do the soap test with the balloons in place.

 

[Chuck]

48 hour update.

Is there any better way to confirm the absence of leaks?

 

[Pete McCluskey.]

Interesting stuff Chuck, I think your balloon test is pretty innovative and seems to be effective. I'm looking forward to the rest of your build.

 

[Jack]

That result works for me too!