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Scratch build Fly Baby (first own design)

DH.98

New member
#1
Hi Guys,

I have already done a few scratch builds but this one is my first own design. I've chosen the Fly Baby because I quite like the idea of the original plane (buy the plans and build it yourself) and because it seemed to be quite easy to build using FT techniques. It's going to have a 600mm wingspan so it should be roughly the same size than the mini Scout (I'm also planning to build a bigger version but that's for later). I have already designed the plane on Sketchup and I'm currently building the first prototype.

Here are some pictures:

-Real airplane:
brain1[1].jpg

-Sketchup design:
Mini Fly Baby III.jpg

Mini Fly Baby II.jpg

-First prototype:
_DSC1885_01.JPG

_DSC1889_01.JPG
 

DH.98

New member
#5
I've now build a second prototype, I did a few small modifications to my first design (some pieces didn't fit very well). The second prototype is 6mm narrower, so that the mighty mini power pod fits in it, but I still have to make some minor changes, so there will be a third prototype. I've also done some test gliding and it looks quite stable and glides better than expected (test glide weight (airframe+noseweight) was 120g). I hope the next prototype will be good enough for powered flight ;) .

_DSC1893.JPG

_DSC1894.JPG

_DSC1896.JPG

_DSC1898.JPG
 

AkimboGlueGuns

Biplane Guy
Mentor
#7
Very cool! nice job on the build. The only things I would change is the size (make it bigger!) and give it a 3D cowl made of posterboard. But what you are doing at this scale is great. Keep us updated on the test flights!
 

DH.98

New member
#8
Very cool! nice job on the build. The only things I would change is the size (make it bigger!) and give it a 3D cowl made of posterboard. But what you are doing at this scale is great. Keep us updated on the test flights!
As I've already, mentioned I will also build a bigger version of the fly baby but that's for later (maybe summer holidays).
For the engine cowl I've tried the one from fiddlersgreen (http://www.fiddlersgreen.net/models/aircraft/Fly-Baby.html), but I'm not really pleased with the result, so if you have any idea how I could build a nicer cowl, please tell me :confused:
 

JohnRambozo

Posted a thousand or more times
#9
I've now build a second prototype, I did a few small modifications to my first design (some pieces didn't fit very well). The second prototype is 6mm narrower, so that the mighty mini power pod fits in it, but I still have to make some minor changes, so there will be a third prototype. I've also done some test gliding and it looks quite stable and glides better than expected (test glide weight (airframe+noseweight) was 120g). I hope the next prototype will be good enough for powered flight ;) .
Nice work. It looks like the transition from Sketchup to prototype is pretty smooth.
 

AkimboGlueGuns

Biplane Guy
Mentor
#10
Hm, I was just thinking using posterboard to make little side cheeks for the engine to give the nose some shape. The cowl from fiddler's green should work, I't's just down to a matter of how much, well, fiddling you want to do with it.
 

DH.98

New member
#11
Hello,
I'm back on the forum, the last few weeks I couldn't write on the forum or work on my plane because I was quite busy working for school or on other projects like this one:

DSC_0517.JPG

Finally I tried to testfly my Fly Baby but it didn't turn out very well, the plane had a bad tendency to roll either left or right and I didn't manage to keep it upright using only the rudder. There were two solutions to this problem, either adding some more dihedral to the wing (but that would have looked stupid) or adding ailerons to it. As the plane was to small to add a third servo for ailerons I now started to build a bigger version, 900mm, with ailerons and none undercambered wings.
 

DH.98

New member
#14
So here it is, ready for the maiden flight, finally I chose to put the NTM 28-26A on it, because I had to put almost 100g of weight in the nose to get the CG right with the AP19.

P1130016.JPG

P1130017.JPG

P1130018.JPG

While soldering new connectors to a battery for my fly baby, I accidentally very briefly shorcut it. The battery remained slightly warm for a few minutes but it didn't change shape, so is it still save to use or should I buy a new one?
 

AkimboGlueGuns

Biplane Guy
Mentor
#15
The build looks nice. I'd test that battery on a motor that is off of the airplane, if it still works then you're probably good, but you should be careful. I'm by no means a battery expert, so take my suggestion with a grain of salt. Try posting a thread in the battery and chargers part of the forum.
 

PeterGregory

CrossThread Industries
#16
Looks great, subscribed. With the servos so far back on such a small plane, you might have had to compensate with part of that 100 grams up front.
Looks good, hope it maidens well.
 
#17
I agree, you have created a very scale and quite nice looking airframe. I would mount the servos internally and more forward, just like the mini series. Very clean looking, juat rear of the wing so a hatch could be used for service if needed.
 

DH.98

New member
#18
Yes, mounting the servos further forward would have been a good idea, but with this motor I didn't need to ad any dead weight and it will have plenty of power (more thrust than weight). Now I'm just waiting for some good weather for the maiden flight.