Progress Report on Wings

Sorry, I have let this Blog down during the Thanksgiving period although I continued to work on the wings. The Deburring and Fluting of the Ribs was quite time consuming and when all the parts were ready I took them to the Alodine treatment in Greensboro. I took also all the spars except the main wing spars which are already anodized for corrosion protection.
Here are the ribs all ready for alodine:

Back all alodined on the shelf, ready for wing skeleton assembly:

Let's start the fun! First the main ribs of the left wing:
One down, 12 to go!

Left wing main ribs done!

And on and on...
Here I am done with the left wing that I had to hang to make room for the right wing:

At this point I am preparing to put the nose ribs on the right wing and the "gotcha" strikes.
When looking for the different nose ribs, I was missing a "forward trimmed" nose rib but I had an extra nose rib which was not forward trimmed: Houston, we have a problem!
As I knew I had trimmed the right number of ribs, I knew that my trimmed rib was somewhere and the only placed would be... on the left wing (hanging on the left) at the wrong place.
I found it there:

I am already working at drilling out the 6 rivets. Note that the room is limited between the ribs it's why rather than using a drill I am using a small electric screwdriver with a #30 drill. The good news: unriveting went swell.
Note for the builders: there is little difference between a forward trimmed rib and a non trimmed one; this is why I caught this error late. Luckily, I had not skinned the left wing before working on the right wing, following the order of the instruction book. At some point I considered skinning the left wing first because of the lack of space in my workshop, this would have been big trouble!
Then finishing the right wing skeleton was a cinch:

This is where I stand today, the last day of November 2010.

I just ordered the fuselage kit which should arrive in 8 weeks which put the delivery end of January. This means I have plenty of time to finish the wings (and find out "where in the world am I going to store them to make room in my workshop". Note: vertical stab and stabilator are already using a guest bedroom).

Brief count down:
Fuselage 2 months: end of March
Finishing kit 2 months: end of May
Avionics 2 months: end of July
Engine 2 months: end of September
Preparing for first flight 1 month: end of October
First flight: sometime in November/December 2011

EAA 1114 Visit of the GE Turbine Engines Plant

Shu Fung, from GE and an EAA chapter 1114 member organized today a special visit of the GE plant located in RTP on Miami Boulevard. There were about 25 members, all very interested and a few quite competent about jet engines. The best part of the visit is that Shu who is working at the plant is passionate about the jet engine business and managed to communicate his passion to an already very motivated group. The result: a visit planned for 1 hour and a half lasted close to 4 hours!  We even saw the engine Alliance GP7000 that equips the A380, that is, the one that does not blow-up in flight...
A few things we learned about modern jet engines:
- The blades of the first stage compressor move to change their angle of attack in order to fight stall, not unlike the wing of an aircraft. This is of course computer controlled as a stall of the compressor would result in a flame out and a few other bad things for the engine longevity.
- The blades and enclosures of the turbines behind the combustion chamber are cooled by air ducked from the compressor chambers.
- The engine starter is not mechanically linked to the turbine shaft, it is just a compressor that pushes air into the combustion chamber to get the blades moving until the ignition and combustion of fuel takes over

Now next time we fly an airliner, we will know what's behind these big cowlings. Whether this will make us more comfortable flying is another story... Did you say A380?
I like my Rotax 912S.

Wing Ribs: a hefty serving of work

Here is a photo of a sample of the wing ribs:

I have shown the 2 types on the picture: right ribs and left ribs. On the picture each set is made of a nose rib and a main rib positioned as they will be in the wing.
To put some spice in the building, VANs is not putting the right ribs in the right wing and the left ribs in the left wing. Right and left ribs are mixed in each wing!
As I will have to remove the labels identifying left and right ribs for the alodine treatment, I needed a way to identify them, hence this picture.


There is a total of 28 nose ribs and 28 main ribs. each set (nose,main) has a total of 140 holes including the lightning holes that are visible on the photo. Each and every of these holes need to be debured... for a total of about 4000 holes (3000 of which will receive rivets). Once the deburing is completed and after alodine treatment, each rib will have to be fluted: Why?
Below is the reason:

You see that the darn rib is not flat which means that the holes of the flange will not align with the holes of the skin. The fluting consists in making small creases on the flang (preferably between the holes!) until the rib lies flat on the table. This process is very time consuming.
My guess is that the time spent on the wings is 80% deburring + Fluting and 20% fabricating and assembling.

Updated list of Builders Web Sites... and more

As my list of RV-12 builders is buried deep into my Blog, I will refresh it regularly through these postings. Just go to:
http://vieilleburette.blogspot.com/2010/07/list-of-rv-12-builders-sites.html

Built myself a deburring station

Took the opportunity of a cheap worktable on sale at Northern Tools. I also bought a cheap drill for the 2" Scotchbrite wheels which I attached to the table. It is easier to hold the parts which are light than the drill. Notice the vacuum cleaner nozzle under the deburring wheel to  get rid of this nasty Al dust. The main advantage of the table is that I can, weather permitting, do the deburring outside the workshop.
This workstation will come handy for the deburring of the 56 wing ribs starting tomorrow.

My workshop tested by EAA Chapter 1114...

Saturday Afternoon I had a visit by a few members of EAA Chapter 1114 as part of the Workshop visits organized by fellow member Hari Gopalan. Below is a picture of one visitor who is aspiring to become the youngest FAA DAR ever:

Dylan Troy, 4, reflecting (no pun intended) on the quality of my riveting of the Vertical Stab. (Photo by Dad Barry)
I had a great time as it was an opportunity to boast about my work, an activity people of French stock enjoy greatly... (just self-deprecating as my American acquired culture kicks in...)

Alodine treatment tested

Went to United Metal Finishing in Goldsboro to have a batch of parts treated. Below is a picture of the result on the Stub Spar Assembly (all parts treated before riveting - click on picture to enlarge for more details on the finishing)

Not too much to show these days, unlike Republicans!

I have suspended following the instructions of section 14 (Rear Spar, Stub Spar, Hinge brackets) to make a decision about priming. Section 14 requires quite a bit of riveting and once riveted, the parts cannot be primed. I am not an avid Primer for two reasons: it is not required by VANS for most of the parts as most parts are Alclad. There are endless debates about the necessity to prime beyond what is recommended by VANS. The most compelling case for priming everything, including Alclad parts is for those who will keep their plane in a coastal area because of the saline atmosphere. The second reason has to do with the extra work, hazardous nature of the chemical products involved and all precautions that have to be heeded to make the priming process safe. I took the advice of a fellow EAA chapter 1114 builder, Noel Fallwell. Noel has been through the full priming enchilada with his RV7 and his position, in retrospect, is that he would not do it again. He gave me a good lead to solve the problem of parts on which the Alclad has been removed by the manufacturing process (i.e. deburing, countersinking, ...): use an Alodine treatment. The interest of the Alodine treatment is that it is a chemical reaction that does not add weight and that provides good corrosion protection. The other interest is that it is a cheap treatment to have subcontracted. Noel gave me the address of a Greensboro company that he used in the past and I was able to confirm their rate ($50 a lot which is all what fit in one basket). They use two baths, one for cleaning and one for "alodining". An additional plus  is that they can provide your batch treated back the same day.
This is what I will do for the wings. The consequence of this decision is that I had to debur all parts I want treated before taking them to Greensboro, hence the little hyatus in my building process.
More soon....