Sunday, February 26, 2012

Skirts Match-Drilled

In the morning I started verifying the fit of the canopy left from the previous day. I saw that I needed a bit more clearance at the aft bow's base on each side to not touch the welds in that area.
The Dremel tool took care of that.

Then I took the time to adjust the forward fit of the side skirts to follow the curve of the fuselage/canopy. I thought this should better happen early so it could be bent a bit too far and then make a good fir while being forced back by the canopy curve.
We'll see if this was a correct assumption. I created the curve by drawing a line on the skirts that matched the one shown in the manual and then used a vise to clamp it and get the bend started along the line. The rest was done free-hand with the help of a paint can.

The last little trimming I had to do was at the weld on both sides of the canopy frame where the skirts would touch and not lay flat. I sanded them down with the Dremel tool and had the canopy removed for this to have easier access. I cleaned the spot and primed it, hence the green stuff you see.

The skirts where then put on place (with the canopy still off) and held in place with clamps to adjust the position as well as to support it during the first few drills until the clecos secured it safely.

Here a close up of the fit at the aft end where it almost touches the turtle deck skin.

And then it was business as usual. Drill, cleco, drill, cleco, and so on until everything got removed again, deburred, some holes dimpled and some countersunk in the frame.
This was when it looked like this.

And this was also the moment when I realized that I don't have any friends.
At least no friends that are non-claustrophobic, as well as lighter than me, and available, all at the same time.
My sister-in-law as well as one of my two nephews could have easily done the job of crawling into the cockpit, getting sealed in by putting the canopy back on and then hold a wooden block against the angle where I wanted to drill a hole through.
However, neither one was available and I hadn't planned for them being "accidentally" around this weekend by reading ahead in time.
So I had to stop here and find something else to do. This something turned out to be the canopy latch handle.
I drilled (a not so precisely done) pilot hole into the handle.

Adjusting the length of the latch pipe and then match-drilling through that latch pipe deeper into the latch handle, was next.

Well, the next step was to open up the holes to #19 and then tap the deeper part in the handle with an 8-32 tap.
Hm, an 8-32 tap? That's new - wonder if I have that ...
Guess what! The Avery toolkit discretely overlooked that I needed such a tap right now. They provide the 6-32, skip the 8-32 and continue at 1/4".
What a show-stopper!
So I had to order that tap and also threw in a 1/8" plexiglass bit but the shipping cost were still 1/3 of the whole order. Ouch!

I hope next weekend will be as warm as this one and that my sister-in-law will have time to help me out with the canopy.

Saturday, February 25, 2012

Canopy Drilled

It was time to drill the canopy today. The ones familiar with this task know that in order to correctly drill the front bow one has to mark the tangent line on this bow to indicate where the canopy makes contact with the bow. The technique described in the manual has not really worked for anyone so far and I wasn't even going to try. I thought that old fashioned typewriter carbon paper ought to do the trick.

The idea is to slide the carbon paper in between the canopy and the front bow with the carbon side facing down so it touches the blue tape that has been put on the front bow. Then, while applying slight pressure on the canopy to ensure contact with the bow, carefully pull the carbon paper out. This should cause a slight friction between the paper and the bow and therefore leave a visible black mark in the blue tape.

Ready to try! I started on the pilot side as this one was more accessible. While pulling on the paper I made sure that I applied pressure along the canopy where it touches the bow.
This is the mark after the first paper has been pulled out.

As you can see, the carbon paper left a very clear mark. I continued with the rest of the papers, repeating what I had done before.
It left a very legible mark all across the bow. It might not come through in the picture too well without looking at the full size picture but I assure you that I had no trouble seeing the line on the blue tape over the whole length of the bow.

Before marking and pre-drilling the rivet holes into the bow, I wanted to make sure that I had a sufficient fit. I read through three or four blogs and examined the pictures. What I saw indicated that I still needed a little detail work.
It turned out that my fit on the aft bow was not good enough and would have left quite a wide gap between the canopy and the aft window. In order to pull the canopy further aft, I had to slightly trim the hole for the latch handle as it wouldn't allow me sufficient travel otherwise.

This put the canopy aft far enough for a tighter fit with the aft window but it will also require me to trim off quite a bit material on the aft end of canopy to make this happen as some areas are extending too far aft. I will not tackle this problem now other than to ensure that I will have enough material in that area for now.
After this step, the canopy came off and the rivet holes on the front bow where marked in 2" distances across its length.

I also pre-punched the spots where I had to drill as the bow would otherwise easily allow your drill bit to wander off. Then I pre-drilled the spots with a #40 bit,

The canopy came back on, was readjusted and taped down to hold it in place during the delicate first few holes until the clecos would do the job.

And then the drilling started. I deviated from the plans in this step as the Avery toolkit provides for a #27 and a #40 plexiglass bit but not for a #30. I wanted to make sure that these rivets would sit tight enough and therefore I created a lot more work for myself. As you can see in the image, I started pre-drilling the canopy with a #40 plexiglass bit using the hand drill which gives me excellent control. I clecoed as I drilled along.

Then, when all the holes had been drilled in #40, I started from the center again with two drills now. First I widened the hole in the plexiglass with a dull #30 bit (drill with an old bit into concrete or a brick to dull it). This dull bit won't catch on exit and it heats up the plexiglass very well to avoid any chips or cracks.

Then, I used the hand drill again, with a sharp #30 bit that would drill through the aluminum into bow. I tried it with the dull bit once and it wouldn't really do it with the hand drill, so I chose this method instead. A lot of work but I cracked the aft plexiglass window and I certainly don't want to do this on the much more expensive canopy. No chance!

This shows the process at a bit more than half the way. No cracks, no chips, but a lot of time ... Eventually I was done with that and it was on to the aft bow. This had a special surprise for me as it required the holes to be drilled and clecoed ALTERNATINGLY on the left and the right side. As I only have one single ladder that would get me in the right position to drill the upper holes, I had a fun time (NOT) carrying the ladder from one side to the other while making slow progress.

On this task I also deviated (due to a lack of #30 plexiglass bits) by pre-drilling with #40 plexiglass bit, using the hand drill and then opening up the hole with the dull #30 drill bit. Again, no problems, but it required very accurate positioning of the #40 bit to correctly center it on the #30 hole in the aft bow.

Before working on the next step of matching the side skirts and match-drilling them, I decided to take the canopy off as I had not cleaned up the edges from this protective cover yet and I wanted to make sure this couldn't disturb the delicate fit of the skirts. I also used this occasion to deburr the holes drilled in the frame as well as in the canopy - at least on the side that doesn't get countersunk soon.
Once I was done the daylight faded and all I could do at that point was to put the canopy back on the frame and take a couple of finish photos. The skirts will have to wait.

Sunday, February 19, 2012

Canopy Trimming

Before I tell you about the trimming of the canopy I'd like to show you some peculiarity about the fit of the canopy on the front bow. Sure it needs some trimming to adjust the gap between the forward canopy edge and the sheet metal covering the avionics. The thing that looks odd is the significant droop of the canopy of the left and right curved area. It appears that it is about 1/8" to 1/4" too far below the surface of the metal reference surface. Not in the center section, only in the curved area.

This area will get covered with fiberglass later but I am concerned that this droop is so deep that I might have problems filling this sufficiently to not show in the fiberglass layup without some serious filling work. I'll have to look at other blogs to see if they had the same kind of fit ...

But on to the actual trimming now. I masked the area to get trimmed with a blue painter tape strip. This made it easy to guestimate the 1/8" gap (which should be at least 1/8" to allow for enough clearance when opening the canopy). All I had to do thereafter was to remove the material that wasn't covered by the tape.
It was a pretty cold day for plexiglass work so I decided to use the space heater to heat up the acrylic a bit.

It was quite a time consuming using that little HF belt sander but the tool is easy to control and the chance to ruin this $1k canopy is quite small. About a third into the work...

... and finally done.

I had to do one additional trim run as the right side didn't show enough clearance but that job was quickly done. After putting the canopy back on and adjusting it, the gap appears to be uniform and large enough.

Now I have to mark the tangent line on the front bow for which I will try to use carbon paper as we used with typewriters. I hope this will work better than the method described in the manual ...

Monday, February 6, 2012

New Rear Window Material

When I tried to order a replacement plexiglass window with Carl, I got a surprising answer:

"I am no longer fabricating the plexiglass window. The cost of shipping, cracking and breakage was the reason I had
switched to a different type of plastic for the rear window. The new type of plastic is called Vivak it is made by the Bayer
Co. of Germany. Vivak is only available in clear, so a tint film must be applied to get the tint required. This plastic is unbreakable
like Lexan but does not have the sensitivity to fuel and solvents that Lexan does."

This new window material lies flat as the Lexan one does, so Van's themselves could replace the fuel-sensitive window with this material. It turns out that this Vivac stuff is also a bit cheaper than the plexiglass and will ship for less as it doesn't have to ship preformed.
I just hope the tinting film will work out ok and stick to the material as I really want to reduce the heat in the cockpit when flying in Arizona's summer.
Carl is going to make one for me this weekend, so we'll soon see how it looks.
To see how fuel resistant this material is, I ordered a 0.1" thick sheet through I'll use that for testing how different solvents are affecting the material.

Sunday, February 5, 2012

And On With The Canopy

I tried to avoid it but now I had to continue with the canopy anyway. This task really is intimidating to me and I am far away from feeling comfortable with it, rather overwhelmed I'd say.
So as usual in such situations the standard procedure of Divide et Impera works like a charm. Split an overwhelming task into smaller, controllable tasks and the problem appears less scary.
First I verified that the frame has an even 1/8" gap to the canopy deck. That was not the case. I had to remove some of the cardboard in the front as it wanted to push the frame up where it should match the arch of the rollbar. I held it down good with a lot of blue tape applying the necessary force on both sides.

Clamping the bow to the rollbar with the wooden blocks providing the reference for the distance was the next step. I noticed the the frame is not completely symmetric. One side is slightly shorter than the other which introduces a little warp into the structure when forcing it into an even distance to the rollbar. Nothing significant as I believe the canopy glass will even it out once attached to the frame. At least that's what I hope.

Fluting those little angles that will hold the canopy to the sides of the frame was slow but easy to do. Seems that I haven't done this job in a while and I got somewhat rusty. Much more challenging was figuring out how to sufficiently clamp these angels to the frame for the match drilling. Fortunately I had two clamps that were just big enough to do the job. After two clecoes it's easy to support and fine tune the fit by hand while drilling.

Match drilling, removing clecos, deburring, re-clecoing and then for the fun part. You know it, I LOVE riveting!!!

Then some masking tape had to be attached to some possible scratch points around the canopy frame. This was in preparation for fitting the canopy.

The protective plastic cover in the canopy only seem to be thick and bulky on the front inside where it should fit to the front bow of the frame. That's where I peeled the plastic off to allow a close contact. The rest I left in place for now.

Wow, this looks impressive. Almost like a plane :-).
The fit that Van's produced is breath-taking but it also created a concern. The fit on the rollbar is so perfect that there is no way for me to compensate for a not quite so perfect match drilling and alignment of the rear window to that very same rollbar. I had silently hoped that I could fix that by trimming the canopy but this is now obviously out of the question. As I had also cracked the rear window while opening up the holes (because of the fact that I HAD a hand drill and forgot all about it and didn't use it), I decided to suck it up and order another rear window from Carl. There's is no point to try to fix this mess, it would very likely just get worse.
Now I just have to figure out how to create the tangent line on the front bow. Blue chalk on blue tape doesn't sound so good. I'll see if I can find some green painter's tape.

Saturday, February 4, 2012

Skyview Ordered

Tonight I faxed the order form to Van's to get my Skyview Avionics package in the queue. I don't think this will even get mailed before 4-8 weeks considering the backlog that has developed over the last year. I am certainly ok with that and can feel the pain of those that went ahead with the engine install and that have a complete aircraft sans avionics sitting in their hangars. These guys should definitely get their package first. I will be covered in resin and fiberglass for the next weeks anyway ...
At least I got my order in the queue and can expect something to happen very soon.

Thursday, February 2, 2012

Food for Thought

A friend made me realize that I had made a decision in secret that I should have been more vocal about. After all, I had expressed my concerns about it here before.
The topic at hand is the engine choice for the RV-12. I had said before that I was considering an alternative to the Rotax 912S and that I was looking into the Viking engine.
I have now decided to not deviate from the plans and go the ELSA route which means that I will be buying my engine from Van's and install the 912S.

The Reasons
When the Viking came out I was hoping that it would sell and install in much larger numbers and quicker than it actually did. The delay was partially caused by last minute production line changes but the result is now that I don't see a large enough number of hours flown on engines not owned by the company that I would trust my own installation flying across a wide open desert. I am experimental - not tired of life, to put it more bluntly.
I don't see this lack of proven hours significantly change until mid 2012 when I want to be ready to hang my engine.
The current lead time for a Viking is around 6 months and that would make it impossible to get my bird in the air this year which is my expressed goal. I am grounded for way too long and I want to finish this build soon.
Even if the availability, and track record would be to my liking, I had still to consider that deviating the plans on my first build to the extent of mounting a different engine would be a very big task to handle on my own. I don't have access to anybody locally who could help me or just give me advise after looking something over. I think just following the plans on the engine install as provided by Van's might be challenging already. I don't even know at this point how much effort there would be involved to get the Viking supported by the SkyView that I bought through Van's and which settings are all locked out and preset tp support the 912S. If this couldn't get fixed, I would have to buy another SV panel for around $3k alone. And the overall savings by going with the Viking are just around $10k given the fact that I bought the kit parts that I don't need for the Viking but that are hard to return now that I have them (cowl, installed fuel pump and gascolator, etc.).

This doesn't mean that I gave up on the Viking or would think that it's not a terrific engine. To the contrary! It is just not my choice at this time for the project at hand.
Once I have flown 1500 hours on the Rotax, I will reevaluate the situation then and it is very well possible that I feel confident to make an engine change and that might very well be the Viking that will have a much longer track record at that time.

Wednesday, February 1, 2012

No More Main Gear Work

I got as far as I could in the Main Gear section. I finally torqued the top engine mount bolts after getting a stronger torque wrench that could apply the necessary 160-190 inch-pounds (this one actually works with foot-pounds and I applied 15 of those). The hole in the bolts lined up perfectly to allow the cotter pins to secure the castle nuts. Getting to those bolt heads was a bit tricky and needed all the extensions for the wrench that I had lying around and it just was enough to clear all the obstructions around the panel.

Then I added all the brake line fitting to the brass blocks and to the wheel brakes so the lines can get attached to these later down the road. I used Bakerseal for the thread sealant.

That was about all I could do in this section before I would have to get the gear legs attached to the fuselage and I cannot do that with the fuselage being located on the BACK patio. The only way to get this monster out the backyard is through a double door gate to the carport and it is just wide enough to clear the fuselage on the rolling workbench. It wouldn't pass with the gear legs attached and so I will go back to working on the canopy section again now that the temps have come back up and will soon stay warm anyway.
If my weather forecast would turn out to be all wrong, I could still finish the gear legs and then remove them for getting the fuselage into the carport to not stall the building process (yet again).
My real hope is though that the Avionics package will become available in the next 4 weeks and that I can finish the wiring in the fuselage so to move on and finish previous sections and get back to a more orderly build process without jumping back and forth to work around the Avionics installation.
And as I just learned on VAF, the Avionics order form for SkyView is finally available. I didn't really expect, so now I have to transfer some funds to be able to pay for it but at least we now see the end of the tunnel!!!