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Scratch and Kit Built Aircraft Discuss and share your scratch built or kit built aircraft as well as building techniques, methods, mediums and resources.

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Old 11-11-2014, 08:54 PM   #1
Zabriel
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Default I couldn't wait longer :)

Hi everybody
I am really very new to this hobby. I was just a modeller who is building plastic modells, and also I am a weekend soldier who plays airsoft & repairs a lot airsoft guns. So I know a little about modelling (building) and repairing some things and learned a lot of things about LiPo batteries...
Then I discovered this hobby
Unfortunately I have no one else around who can advise me or teach me
So I read a lot in many forums about building & flying & scratchbuild foamies & building techniques etc... I downloaded a free plan (F-22), built it, tried to fly it, did all "don't"s, crashed it (it was obvious-but had a lot of fun & learned a lot of it ).
But I couldn't wait longer and decided to build totally new thing to me: My boys toy; a Cessna Seaplane. I finally finished it but until this moment I couldn't maiden it yet. Because of bad weather or time issues

I tried to attach some photos but was not able to. I am waiting for a administrators respond. I will try it later...
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Old 11-11-2014, 09:12 PM   #2
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Good luck when it comes top the maiden flight.
If it's a float plane my advice would to be to take the floats off and fit conventional landing gear until you get the hang of it, or even remove the floats and fly it with no landing gear, justy hand launch and belly land.
The thing is the floats will be vulnerable to damage if landing on grass and trying to fly from water when you havent flown before is just a bad idea for many reasons...
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Old 11-11-2014, 09:19 PM   #3
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Thats the point: I always try the hard way first! I couldn't upload photos of it but I think I managed to resize it to make one photo of it as an avatar. The CoG is about 15mm or maybe 20mm back as I planned. A little tail heavy. But I built this plane to test my building skills
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Old 11-11-2014, 11:12 PM   #4
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Tail-heavy == death. If you even suspect it might be tail-heavy, consider putting some weight in the nose until you get CG sorted out. There's a saying that nose-heavy planes fly badly, while tail-heavy planes fly only once.

Best of luck!

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Old 11-12-2014, 01:43 AM   #5
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Agreed - bump up the battery size = correct balance more air time! A shade nose heavy is cool, even a smidging tail heavy is a nightmare. If you insist on going off water (not salt I hope) bag everything you can and consider hosing down all electronics with Corrosion-X. Be ready to commence drying out your gear because in my experience, something will get wet even with precautions.
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Old 11-12-2014, 06:55 AM   #6
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Regarding the CG... it depends what you mean by 15-20mm back... back from where? This being a float plane I was assuming you meant 'back from the step in the floats', which should be fine when it's on the water. How that relates to having a proper CG for flight I've no idea but as a rule of thumb (and a very rough and sometimes incorrect rule of thumb) the CG should be in the 25-30% of wing chord range (measured from the leading edge of the wing, assuming straight, unswept wing)
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Old 11-12-2014, 01:34 PM   #7
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Thanks all for the replies. Finally here are some pictures. There is no much room left inside. The CoG is about on the straight part of the servo cables, as seen on the last pic. But I believe it should be more closer to the leading edge of the wing.
The floats are too big. I was also not sure how deep it "swim" on water.
As I said before, I like the hard way to learn, so I can understand problems better.
Of course I hope it flies well, but it was a challenge to me to build something like this without any plan. Trying out some "new to me" techniques was my first goal. Without any plan I couldn't be sure where the CoG had to be. I read somewhere that some rc pilots like to fly just a little tail heavy.
It is 100cm wide, about 80cm it weighs almost 900gr. Heavier than expected. I am looking to move the CoG forward without adding more weight. Any suggestions? Maybe trimming the too big stabilizers?



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Old 11-15-2014, 05:58 PM   #8
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CG is way too far back. Should be at 25 to 30% of the wing chord/width.
Although I'm probably too late.

Gord.
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Old 11-16-2014, 03:30 AM   #9
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It's good to move gear in order to avoid ballast, but I wouldn't worry about adding weight, especially with a subject like yours that should tolerate some. Like many modelers, I used to cringe at adding ballast for CG setting, until I realized that the model will actually fly like a lighter airplane with the CG set properly, even with the added weight. I had a few difficult subjects that I thought would not tolerate the added weight, which seemingly had more power once the required ballast was added.
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Old 11-16-2014, 09:40 AM   #10
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Originally Posted by Bill G View Post
... I used to cringe at adding ballast for CG setting, until I realized that the model will actually fly like a lighter airplane with the CG set properly, even with the added weight. ...
Thank you very much for the replies. This sentence above is a real turning point to me. I will consider it.

flypaper 2: it cannot be too late if I'm learning
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