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Old May 27, 2009, 06:39 PM
S55
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Beaverton, OR, USA
Joined Feb 2001
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Bombardier CL-415

I kept flying the models I have whenever weather and spare time allowed, but havenít built anything since 2007. Got into this new hobby:
Senorita (1 min 3 sec)


Suddenly I got the building bug and decided to do the CL-415. Before starting the guitar thing I was thinking of learning Rhino and use it to build models. Now I can tell itís not going to happen. Constantly dedicating at least one hour per day to guitar practice can only allow for quick, cheap and dirty builds.

Well, the 415 deserves better, so it wonít be that cheap, but I wonít care much about details and scale.

Since I will use some techniques that go well with any model, I will post it here in the Scratchbuilt section because there is more traffic

Thanks,
S55
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Old May 27, 2009, 07:17 PM
S55
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Beaverton, OR, USA
Joined Feb 2001
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The 3-view drawing I used is available here, if you click on the Specifications and Performance tab.
http://www.bombardier.com/en/aerospa...1260d80008fff#

I enlarged it at Kinkoís to 40 inch wingspan and followed these steps.

Two template pairs were made of formica: one for top/bottom and one for left/right. Sanded the edges very carefully so the hot wire would slide nicely on them.

Then I cut a plywood piece following the keel line and glued/sandwiched it between two foam blocks. Then I used the top/bottom templates and hot wired the sides.

After that I placed the left/right side templates and hot wired the hull bottom. The plywood keel was helpful during this step as the hot wire was resting on it and on the side template.
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Old May 28, 2009, 01:28 PM
S55
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Beaverton, OR, USA
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Finished sanding the hull bottom. Still need to figure out how to do the ďnoseĒ so it can be removable.
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Old May 28, 2009, 01:30 PM
S55
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Beaverton, OR, USA
Joined Feb 2001
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Canít decide which approach to use for wings. The easiest way is to use bluecor sheet and thin down the trailing edge (easily done with hot wire), then wrap it with 1 mm depron. CF tube added for stiffness. I tried it on a little piece, just to see how it works. The curving was done with my heated bending device. I used epoxy on this one and rushed a bit so the lamination is not that perfect. I will make another test using white gorilla glue.

The other option is to use foam cores with a nice airfoil shape and then carve with hot wire to reduce weight. After that, wrap it with 1mm or 2 mm depron. This structure is stiff even without CF tube.

Estimated wing weight is 110 grams for the first approach and 100 grams for the second one, so not much of a difference from this point of view. The question is: which one provides more lift at slow speed?
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Old May 28, 2009, 09:37 PM
Departing at 'O' dark 30
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Sudbury, Ont. Canada
Joined Feb 2002
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Ok, im in

Wanting one of these for ever! Just got to finish my Hurricane and i will build one too.

I think i want at least 42" span though. How much room will you have for props with the 40" span?

Go for the foam core wing.....
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Old May 28, 2009, 10:08 PM
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Denton Tx.
Joined Sep 2003
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Hi S55, Looking good so far.

Here is a free set of plans for the CL-415 with a w/s of 67in. Maybe it can help you with some idea on your build.

http://www.aerosquare.com/content/ca...24/42/lang,en/
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Old Jun 01, 2009, 12:20 PM
S55
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Beaverton, OR, USA
Joined Feb 2001
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Done some work this weekend, but basically no progress. After deciding upon using hollowed foam cores and starting the 4th pair of wings I ended up messing up the left one, so I will have to cut another one and Iím afraid my spare time budget is low till next weekend.

Thanks for the plans, but like previously said I will not care much about details and scale. I enlarged my initial plans for 40 inch wingspan which called for 5 inch chord, but will now stretch the wings to 44 wingspan and 6.5 chord. I am obsessed about weight so I am trying to get more wing area while keeping the other dimensions roughly unchanged. I plan to have ailerons and flaps. When covering the fuse I will be able to lengthen it by roughly 1 inch. Will post pictures when I get to the fuse covering job since itís a new way of doing it (I think).

The motor nacelles will be a bit farther apart to allow for 8 inch props. I am not sure yet if 8 inch doesnít get them too close to the water. In that case I will use 7 inch and probably go with 4-blade ones.
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Old Jun 01, 2009, 02:27 PM
Ajutor de băgător de seamă
San Carlos, CA
Joined Mar 2004
734 Posts
IMO, if you enlarge just the wings, the plane will become too twitchy.

Even a scale model will suffer from the very short distance between the wing and tail. Increasing the wing chord pushes the COG even closer to the tail, making the situation worse.

If you don't care too much about the scale feel, I suggest to make the fuse longer.

Cheers,

Şerban
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Old Jun 01, 2009, 05:12 PM
S55
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Beaverton, OR, USA
Joined Feb 2001
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Serban, youíre right. The plane is a bit short coupled to begin with, but I will keep the COG where it was with respect to nose and increasing the fuse length by 1 inch will help.
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