Hi All:

I started the Plecan Falcon back in early February and have been posting on another Vintage site about the build. The enthusiasm is high but traffic is low there. I figured I would throw my hat into the ring for the 2012 build off located here.
I will quickly re-post what I have already accomplished and then post along as my build progresses.

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I am going to keep this a simple build posting. I plan on posting quickly the routine building parts and show more detail on changes I make or more interesting building techniques.
Please keep in mine I have 6-7 other builds going so like flying oldtimers I will be slowly posting along on this one.

Initally I was leafing through an AMI mag. and came across a pic of an oldtimer. It looked interesting but I couldn't ID it and there was no description of what was in the photograph. I scanned the pic and then I could read the name Falcon on the side. I posted it on the vintage forum and within an hour I was told it was a Falcon by Paul Plecan and it was published in the September 1940 Model Airplane News. I also now had another picture of it.
With this info in hand I posted in that famous plans thread and within 12 hours I had a scan of the 1940's build article. Love the internet.

And away we go.

Attached pics show the scan I took and what I received.

Chris

The specs. come out to a 60"ws and wing area 549sq in.
Overall length 38", with the weight around 2lbs. 4 ozs. depending on the engine used.
I am an electric guy and this will be electrified for what I want to do.

The article does recommend a couple of different engines of the day.
Baby Cyclone .363 cu.in disp.
Gwin Aero or Mighty Midget .45 cu.in disp.
a Hurlemann .488 cu.in disp.
or a O.K. .49 cu in.

Chris

I looked around the internet and found the engines that are listed if anyone is interested.

First two are the baby Cyclone. The next one is the Mighty Midget, then the Hurlemann. While the last pic is of the Ok 49.

Chris

I should post a little of where I am at in building the Falcon.
After looking over the plans for a couple of weeks I decided to build the wing first as it is needed to finish the pylon on the fuselage.

I must say this is a builders model as most model aircraft of this time were. You not only have to scratchbuild the plane but also the plans. It is a grid system.
Well this is the 21 century and we have computers. With the plans scanned in PDF I simply tiled up the size I wanted and printed them off at a 60" ws.

Once I taped the wing section of the plans together the 1940's bit me. Well with a plan scanned from a page in a magazine that is over 70 years old there must be distortions present. Maybe the grid on the plan wasn't the best at the time of printing, Paper size changes from humidity over the years and maybe the scanner but I ended up with a interesting scale on the wing.
Well the pencil, paper and ruler still work so I set about creating the wing plan. At least it will be scaled correctly now.
Next I started on the ribs.
There is a sheet provided that has all the various ribs printed on it but again some of them were out and I had to resize them a bit to the wing chord.
With the paper cutouts I can now cut them out of balsa.
Oh, I also cut out the trailing edge paper outlines and had to resize them a little.

Chris

A little more progress tonight. Selected some nice 3/32 C grain balsa and cut out the ribs. Most people I talk to hate cutting out ribs but I seem to enjoy it. To me it seems like a lot of progress is being made on the build. Anyway I now have two nice stacks of ribs.

Onto that strange wing spar.

Chris

Well, I have never seen wing spars like this before. I guess I can put this in my box of building techniques I have now done.

The plans or build guide doesn't mention what the wing spar is made of. I assume it is 1/4" hard balsa. I am going to use Popular. This is something that another builder mentioned a few years back when he was building spads. The popular comes in various widths and lengths and I have built a few plane spars with it and have been happy with the outcome. The nice thing is there are no knots to contend with.
I hope I can describe cutting out the two spars. Basically the spar tapers from the root to the tip. The top taper becomes more aggressive 1/3 of the way from the root and finishes at the tip. The bottom taper becomes convex into the spar 1/5th of the way from the root and comes out 1/5 from the tip only to taper up again a few inches later to the tip. The convex in the spar allows the underside of the spar to match up with the undercamber in the ribs.
Make sense?
Anyway here is the pic. Might help make sense of my previous explanation.

Chris

Onward with the build. Tackled the wing leading edges.
The plans call for 1/2"x3/4" soft balsa. Well I know I don't have 1/2" balsa and if I did it wouldn't be soft for bending.
Really the only solution is laminating up the wing leading edge. This would allow me to put the wing together without the leading edge trying to snap out of place. It would also be much stronger.
I traced a paper pattern of the front of the wing and transfered it to a piece of scrap foam. You could use a couple layers of cardboard to do the same thing instead of the foam. I stripped six lengths of balsa. Two 1/4" thick and four 1/8" thick. I stripped the balsa longer than I needed just in case of the opps factor. I basically glued one of the 1/4" and two of the 1/8" together with Weldbond. I rubber banded the glued balsa to the foam form I made earlier and proceeded to clamp the whole thing to the work bench to keep it straight until it dries.
Tomorrow I will glue and clamp the other side.

Chris

Not much excitement here. Left wing assembled and glued. You can see the shape of the Falcon wing emerging. Fiddly work mostly. I cut the slots in the ribs at this time to make sure they indexed correctly with the spar.
I changed the plans a little and elongated the ribs by 3/32 on both ends. I also made matching slots into the leading and trailing balsa with stacked hacksaw blades. This allows me to index the ribs into the balsa. Just stronger than butt joining them.
Will be adding some triangles and some other bits for reinforcement, then onto the other wing half.
Well I kick myself that I didn't make the spar 3/32" longer. I then would have been able to slot it into the tip balsa. Anyway I had to butt join it and add some small triangles on the sides for strength.

Chris

I seem to have the right wing half finished. Trimmed some of the excess balsa leading edge off. Started to make the pieces so I can assemble the two wing halves. You can see the two wing joiners in the pic.
I decided to sheet the two top inner bays of ribs. I figured the rubber bands that hold the wing on would cause damage on open bays. Basically just used a balsa stripper and took 3/32" off the top of the three root ribs.

Chris

I decided to tackle the leading edge on each wing and round them up to the ribs. I can now use one of my favourite tools. The razor plane. I figured now is the time, as I can easily manage the wings halves before they are assembled. The only real issue is to be careful not to damage the ribs by nicking them with the blade. You could sand the leading edge but that is messy and takes too long in my books. Go buy a razor plane it is well worth it.

It doesn't take long before I am covered in shavings and the job is done. I also tapered the leading edge into the wing tips.
Did I mention, I really like using the razor plane.

I lightly sanded the ribs to just knock any rough or high points down. Since the ribs are all different heights. I checked the ribs with a straight edge to make sure one rib flowed to the next rib without any high or low spots.
Well the 1940's plans came back and bit me again.
It looks like 3-4 ribs need to be built up. Particularly the 3, 8 and 9 rib on each side. Back to the fiddly work.

Since taking a pic of the finished rounded leading edge is boring I will show you a nice pile of shavings from one of my favourite tools.
"The Razor Plane"
It is best to clean the pile up when you are finished. It is surprising how quickly it gets tracked around the house. Don't ask how I know.

Chris

Nice looking design Chris, love that wing shape! Watching your build with interest.

Originally Posted by Sundancer

Nice looking design Chris, love that wing shape! Watching your build with interest.

Thanks! When I saw the wing, that is what tipped the scales and I had to build the Falcon.

Chris

What a fabulous wing...andd what a fabulous build. Certainly something out of the ordinary. Thanks for sharing, and please do keep us updated.

Regards
Chris

Beautiful model.

Cem

Thanks Chris and Cem.

Took me a couple of days but I think I have now fixed the ribs.
Started to join the wings. Will post pic tomorrow.

Chris