| August 1-3 |
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The past few nights have been spent studying the plans and
cleaning the workspace in preparation of cutting the center ribs. As usual
I'm probably over-thinking the process. Oh well, when I'm satisfied that I
won't be screwing something up too badly, I'll start cutting. |
| August 4,5 |
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What a great build weekend. I ended up having to
draw out in and exploded parts type view the way the spar caps were assembled on
the spar. I finally got the proper rib sizes figured out in my head.
Once that was figured out I could spend some quality time sanding |
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I am going to use the same router method that I used on the nose
ribs. The first step is to make a template with the 9/16 flange. |
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I made the template 1/4 inch short on the main spar side and 1/8
short on the rear spar side. I'll describe why in a couple of
minutes. Once the main center rib template is complete I need to make a
duplicate of the template so I can sandwich the rib black between the two.
The simplest way I know of to make an exact copy is to use the laminate bit and
simply route it to size. |
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The reason for cutting the ribs short by 1/4 inch on the main
spar side is to accommodate the varying thicknesses of the spar cap. I
borrowed a chapter from Russ Erb and got some 1/8 thick aluminum stock and made
two inserts for the end of the rib template. I made the center hole
off center so that I can only put the spacers on one way. |
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With these two inserts I can make the template be full
thickness, 1/8 short or 1/4 inch short. In this picture I've got the
spacer clamped into place while I inserted the screws.
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I managed two minor screw ups in this process.
One: I sanded the rear of the template 1/16 too much. The
solution was to sand another 1/16 too much and add a 1/8 insert to the rear spar
side of the template. Problem solved.
Two: I got in a rush when I was drilling the pilot holes for the wood
screws I used to hold the inserts in place. I neglected to check my drill
bit size. The result was a pilot hole that was wider than the thread of
the screw. The solution? I dripped some gorilla glue into the holes,
inserted the screws and clamped them in place for the night. The
insert on this end doesn't need to be changed out, so gluing it in place isn't a
problem. |
| August 6 |
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After letting the glue set overnight, I was ready to start
cutting my rib blanks. The same process that I used for the nose ribs
would be used here.
- cut the blank slightly oversized
- place the blank in the master form block to get jig pin holes drilled
- clamp the blank in the routing jig.
- route the blank to size
- debur the edges. I don't debur the holes at this point, since all of
the holes will be drilled out to be the lightening holes later.
The only difference in production from the nose ribs was that this time I
labeled and kept score of which ribs (different length) had been made.
In retrospect, I kind of wish I had cut the nose ribs to size when I was
making them. Time will tell if it will make much difference.
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With all of the .025 center ribs cut it was time to start
hammering flanges. I made two piles of ribs. I checked and double
checked to make sure that I had the proper ribs in the proper piles. Once
I was confident that I had my left and right wings fairly represented I started
hammering the flange. |
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I placed the routed rib into the master formblock. Using 5
of the 1/4 inch holes I had already drilled I secured the blank in an MDF
sandwich. Once secured, I marked off the general rivet spacing. This
will ensure that I don't place any flutes where a rivet might be placed
later. |
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Once I had both flanges marked I laid the whole formblock down
on my bench with one side overhanging the edge. I have a note on the
backer block to make sure that I'm hammering the correct direction. |
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It was a good day of work. I got all but four of the .025
center ribs flanged. |
| August 7 |
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Tonight I hammered the flange on the remaining .025 center
ribs. I seamed and fluted two ribs after that and called it a night. |
| August 8 |
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I got 5 more ribs squared up tonight. That completes the
job for one wing. Well, it completes it for the .025 center ribs anyway ;) .
I decided to start in on the lightening holes just to mix it up a
bit. I got three cut and called it quits for the night.
About the only other thing I did tonight was to install a cheapo wall mount
fan. |
| August 9 |
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I fluted the other 7 .025 center ribs tonight.
I also finished cutting out the center lightening hole in the rest of the
batch. |
| August 10 |
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More work on the ribs last night. I set up my high-tech
flanging station and flanged half of the pile last night. I'll probably do
the other half tonight.
Just so you don't think I've fallen off the planet, this will be my last
update until the 21st. |
| August 11-16 |
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The 11th through - 16th were spent camping in NH. It was
pretty nice. No cell service, quiet, disconnected. I wish I
could have stayed. |
| August 17-20 |
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I worked on and off from Thursday through Sunday. The main
hurdle I'm wrestling with is the cutting of the .025 oval lightening
holes. If I had been thinking straight, I would have cut the ovals first
with a router while I still had all of my jig pin locations intact.
Instead I cut three of the five lightening holes first, leaving me with only
one jig pin location to secure the rib to a form. Not good.
I think I'm going to buy a dremel hole cutter attachment and make the ovals
that way. I'll post more detailed pictures once I get the process figured
out.
I did try to make the oval with the fly cutter. It works, but it's
messy. Lots of clanking and jamming. It's just not the way to get
the job done. At least it isn't for me.
While I'm waiting to come to a decision on my course of action, I started
laying out the lightening holes for the back ribs. |
| August 21 |
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After weighing all of my options, I ended up taking another stab
at cutting the holes with my fly cutter. If I took it slow and cut a bit
off of each circle at a time, I was able to get good results. I'm happy to
report that the oval holes are behind me.
Here's a run down of the basic process I used. Bear in mind that if I had
planned this out better, I could have saved myself a lot of aggravation and
simply routed out the oval the same way I had the rib.
Since I had cut three of the five lightening holes in the ribs already, my
options were a bit limited. Most of my jig pin locations (lightening hole
centers) were gone.
First I made a backing block for the operation. I did this by placing
the 2.4 under the master form block and drilling out the remaining two jig pin
locations.
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Next I placed the center rib on the block with two bolts
sticking up through. |
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I then placed the master form block over the rib and clamped it
down into position. |
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Next I used a hand drill to drill the pilot holes for the two
circles needed to make the oval hole |
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Here is the rib after it has been screwed down to the drill
press. The screws are in the centers of the two remaining jig pin
locations. This serves two purposes: One it keeps the rib stationary
while cutting, and two it keeps the waste from the cutting process in place so I
can cut both holes. |
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Here's a picture of the process when both holes were cut half
way through. Almost there :) |
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Finally! Here's a picture of the rib after the holes have been
cut. All that is left at this point is to sand the peaks where the circles
meet flat. |
| August 22 |
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Last night was "tape the maze night" on the farm.
I spent about 20 minutes total out in the PK skunkworks facility. I sanded
down the peaks in the ovals, making them. . . well. . . oval. |
| August 23 |
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Tonight was another light night. I cut the last of the
lightening holes in the .025 center ribs and of course took the obligatory
picture. |
| August 24 |
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see all of those holes in the picture above? Well tonight
I broke out the Bobstick3000 and had at it. 70 holes later, I was
done. I didn't have any arm left, or I would have started in on the push
tool to flatten them all out. Maybe tomorrow I'll do that.
Before I do any push tool work I need to make a push station for the center
ribs. I don't think the setup I used for the nose ribs will work quite as
well for the center ribs. |
| August 25-30 |
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Friday night I set about making the new and improved push
station for the center ribs. I used another chunk of MDF (yes the same
single sheet I bought when I started this whole process) and drilled the
lightening hole centers just like it was a rib blank.
Then I increased the size of each hole to account for the rib flange
area. Once I had all of the figuring done, I started drilling. The
result turned out pretty darned good if I do say so myself. |
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The only thing I found that helped was the addition of a scrap
block of mdf on the narrow side of the formblock. you can see it in the
picture above. This helped keep the rib from sliding around as I did the
pushing |
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Here are the before and after push pictures of a center
rib. The bottom picture is not quite finished, but it's the only
"after" picture I have |
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After finishing up the pushing I moved on to the back ribs
4 of them. I knocked them out scary quick. Well scary quick for me
anyway. I had to head over to The Home Deopt Aircraft tool department to
get a 1.25 hole cutter. It seems that my fly cutter doesn't go that
small. so the last two holes would have to be done in a different
manner. The smallest hole will get a .5 drill bit and the next one up will
get the 1.25. |
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Since I couldn't finish the back ribs I took stock of the
remaining aluminum and what I needed to get out of it. If I cut much more
I wouldn't be able to cut the wing tip ribs from what was left, so they were
next up. I didn't do much other that cut out the blanks and set them
aside. I'll finish them up some other night.
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This brings me to Tuesday night. Tonight I started cutting out
some of the aileron and flap ribs. I was able to get 7 or 8 blanks cut out
of the aluminum before I ran out of pieces big enough to get more ribs out of
it. I still have some left for the nose and pocket ribs. I'll see in
the next few days how much I can get out of it.
In any event it's time to order some more aluminum. This will be a sizable
order. I hope to have enough money to be able to order up my spar and the
remaining rib aluminum all at once. I've spent the last day or so working
out how much of each I need to get.
Yes, I know that others have written down what they used, but I want to
figure it out for myself and then check against others. |
| August 31 |
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Here I am at the end of August. Almost four months into
this project. I have to say I'm pretty happy with the work I've managed
to produce so far. Considering I have no idea what I'm doing ;) .
At any rate, I've been spending a lot of time working up the aluminum
order. There hasn't really been too much in the way of actual metal work
this week. I think I'm just about ready to pull the trigger on this
one. It should give me enough to finish making the wing structure, but
not enough to skin it. |
| back, next |
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