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Old Mar 11, 2012, 03:47 PM
Why Yes I Fly!
schroeder4's Avatar
United States, IA
Joined Oct 2009
161 Posts
It's finally finished!

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After about 2-1/2 years my Citabria is finally finished! I still have some issues with my radio to work out before final pre-flight trimming, but then will just be waiting for warmer weather for the maiden flight. Thank you again EJWalsh for creating this bulid log as my plane is certainly better for it.

Bernard
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Old Mar 11, 2012, 05:43 PM
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mamethot's Avatar
Montreal, Qc
Joined Jan 2007
242 Posts
Beautiful!
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Old Mar 11, 2012, 06:33 PM
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EJWash1's Avatar
United States, WA, Hoodsport
Joined Mar 2008
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Oh man, is that sweet!

Great finish! Did you end-up painting the white covering?

Please post pics of the maiden when you get to it.

EJWash
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Old Mar 11, 2012, 09:48 PM
Why Yes I Fly!
schroeder4's Avatar
United States, IA
Joined Oct 2009
161 Posts
Thanks, it's not perfect, but I'm pretty happy with it.

The paint is one thing I will do differently next time. The white covering is precolored white Solartex, with yellow LusterKote spray can painted trim. This worked well. However, the white cowl, landing gear and struts are painted white with Testors spray can, with Lusterkote yellow trim, and a LusterKote clear over the top to make the Testors paint fuel proof. Unfortunately, the Testors and LusterKote finishes were not entirely compatible, causing some runs and peeling yellow trim when removing the masking tape. It's not very noticeable, except to me, but it was kind of aggravating at the time.

Bernard
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Old Mar 11, 2012, 10:07 PM
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United States, WA, Hoodsport
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We are always our own worse critics.

I find that the difficulties I experienced during the build all blend-in and go away at the maiden.

EJWash
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Old Mar 11, 2012, 11:00 PM
KE your cub.
Curare's Avatar
in the gutter, again....
Joined Jun 2005
4,166 Posts
Gorgeous! I hope you're going to put some pants on!




Maybe a set for the plane might be an idea too.
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Old Mar 12, 2012, 11:18 AM
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LesUyeda's Avatar
San Diego, California
Joined Dec 2004
3,526 Posts
"Thanks, it's not perfect,"

I have been building a LOT of years, and I don't think I have EVER done one that was "perfect", but a lot of other people thought so":-))))))))

Les
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Old Mar 12, 2012, 11:25 AM
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SLC, Ut
Joined Apr 2010
118 Posts
Beautiful job and ditto on the pants thing.
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Old Mar 15, 2012, 05:41 PM
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Canada, MB, Winnipeg
Joined Nov 2011
332 Posts
Thrust Line and Plastic

Nice build EJ, a very good read, lots of clever little ideas, and a nice plane. Love to see it painted and flying. Anyway I just wanted to toss in my 2 cents.

In posts #356 - #367 (page 24 & 25) there is a discussion about how the hood line is sloped on the model and the real plane has little or no slope. Everybody agreed that kit manufacturers have to make adjustments so that the model will fly. You were very close to the right idea when you started thinking about the thrust line. We balance a plane's cg nose-to-tail at the wings and the Lateral Balance (left to right).

In order to propel an object correctly (straight) the thrust line must go through the center of the mass. The mass (weight) must be or close to where you have 50% above and 50% below the thrust line. On the real Citabria the fuel tanks are in the over head wing, which makes the plane top heavy because there is not much below the thrust line. In the model the fuel tank is low in the fuselage along with a battery(ies), RX, and servos so now the thrust line has to be a lot lower. I think and I guess the engineers thought a sloping hood line looks better than a flat raised (kind of bulging) hood line. In both cases (Real and Model) the engineers have to take all this into account and make a very good guesstimate where to put the engine for the best thrust line.

A good analogy about how this works would be a toy boat with a keel. If you put the pull string on the right side the boat will want to go to the left when pulled but, will go straight once you stop pulling. In our case the plane will want to ascend or descend under power. You could trim up the radio but, with the control surfaces neutral the plane should not slowly ascend or descend under thrust or wind gusts.

As for the plastic and the crazing, I call them shadow cracks because they will cast shadows onto a sheet of white paper placed behind the plastic. The only way to stop it is to use a mold of some sort that is close to the shape you want and slowly heat the plastic until it can be softly pushed down around the mold. Problem is getting the heat just right; to much heat and the plastic will shrink, thicken, and stiffen, not enough heat and the plastic will still develop crazing. I have found that UV light will cause this type of plastic to become very brittle with age and the UV also causes more crazing. I wish I could remember the type of plastic that I use to use, all I can remember is that it is the same type they use for vacuum molding.

Ray
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Old Mar 16, 2012, 11:47 AM
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San Diego, California
Joined Dec 2004
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"all I can remember is that it is the same type they use for vacuum molding."

PET G.

Les
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Old Mar 17, 2012, 09:19 AM
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Central Lake, Michigan
Joined Dec 2002
1,414 Posts
Great looking plane. I noticed you don't have the wheel pants on, but that's no big deal. They're difficult to keep on if flying from grass fields.
Do you have any close-up photos of the windshield? I'm having a heck of a time trying to get mine to fit and I have no idea just how it is fitted around the upper fuse former that's airfoil shaped. I've ruined a couple sheets of plastic even though I used paper patterns to get it set up. Cutting around the very tight curve at the top of the cabin has been the worst problem.
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Old Mar 17, 2012, 02:18 PM
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United States, WA, Hoodsport
Joined Mar 2008
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Quote:
Originally Posted by Nav_Aids View Post
Nice build EJ, a very good read, lots of clever little ideas, and a nice plane. Love to see it painted and flying.
Thanks Ray!

EJWash
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Old Jul 16, 2012, 12:23 PM
Why Yes I Fly!
schroeder4's Avatar
United States, IA
Joined Oct 2009
161 Posts
This thread has not been very busy. We maidened the Citabria and did not like it at all. It is the most squrily, bad flying plane I have ever flown. Luckilly I was able to make a video of it before it crashed due to it's squrilyness. I was really dissappointed I was expecting a lot more from this plane. It cold not even handle a 5 mph crosswind without it flying out of control. I do not think there is anything we can do to make this plane fly well so we are just going to put the engine into a ucando3d .46. Enjoy the video.

(we had dual rates on it and it still flew awfully)


Flying the Sig Citabria: One Last Time (5 min 24 sec)
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Old Jul 16, 2012, 12:58 PM
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Well, I watched the video twice, and I couldn't see any "squirlyness" - but I was not at the controls, you were. Your report is appreciated.

I built this kit to take out to the flying field with me so my friends that are not into R/C can get a "taste". I did not build it for any higher performance than that.

I can understand the model being a tad "pitchy", as it has such a short tail moment. I bet that pushing an aft C.G. (NOT saying this is the case with yours) can turn it into a handful...

I waited too long to paint mine, so now I'll have to wait until early fall.

EJWash
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Old Jul 16, 2012, 03:23 PM
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United States, CA, Clovis
Joined Mar 2004
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I can say my Great Planes version is a bit squirrelly too. I found its more of finding out how they fly.. and what techniques it takes to keep her straight.. and they do take a few different techniques. I would imagine the Sig version is a bit easier then the GP's, as the GP's has a fully symetrical wing.. and is a tad smaller.

Do you have any other experience with a high-wing tail-dragger? Overall theyre just a bit different then a low-wing sport plane.. don't give up though.. you'll get it flying good... I'm thinking its just a learning curve.
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