[spejic]

The Alenia Aeronautica Sky-Y is a testbed for the engine and control systems for the two-engined high altitude Molynx UAV. It just might be the prettiest aircraft in a class noted for producing the opposite. I was looking through a Alenia Aeronautica brochure when I spotted a 3-view, so I thought I'd see if I could stretch my skills to produce the curves of the fuselage. I don't know if I can do it, of if I can do it before the group build is done, but I want to start it.

First job is, again, printing multiple copies of the 3-view on paper which will be the template for the parts. This is a big UAV - about the size of a WWII fighter. Making the wings out of laminated strip plastic won't be strong enough, so I thought I'd carve them from the wings of a Dragon F-15 kit I won't be building.



In the corner you can see the test of the decals I made. In doing this, I found that the aircraft had about 4 or 5 slightly different marking schemes, and there aren't really that many images of the aircraft on the internet.

[spejic]

I carved out the wings, and they look really good. I was right - using the solid kit plastic made a very strong wing piece, and it withstood some heavy sanding with no bending at all. I also made the tail fins, and cut out some profiles in three dimensions of the fuselage. I've also sourced the right rods for the tail booms. This is going to be a very sturdy craft when it's done.



Unfortunately, I'm in a quandary as to how to build it. I've never done any sort of cross-section scratchbuilding before. I'll have to think about this.

[HOLMES]

Spejic,


I think you have taken on a challenge with this scratchbuild but I KNOW you will be able to get it done.

Looks like a marvelous choice for a build and look forward to more of your updates.

Please post when you are able..

BEST WISHES & GOOD LUCK.

HOLMES

[spejic]

Here's my first attempt at making the fuselage. I put in cross sections in all three dimensions. I will add more. Then I will fill in the gaps, sand it down, and it will have the right shape and be symmetrical. That's the plan, anyway. You won't see it, but there is a slot in the bottom to fit the wings.

Speaking of wings, I glued them together so they have the right dihedral. Now that I have them together as one piece, I see how they have slightly different curves, so I still need some more sanding. The wing is heavy, but the tail is so far back that I will need lots of weight in the nose. The lines you see are filled in panel lines from the F-15, but I will make lines for the control surfaces once sanding is done.



I've also done the tail booms out of nice thick plastic rods from a Evergreen random rod-and-tube pack so I can't tell you what diameter it is. I just forgot to put them in the picture.

[drhornii]

good start!

[spejic]

No big update - I just added more cross sections and made a hole for the nose weight, and ended up making something that looks like a dinosaur skeleton.

[spejic]

I'm still working on this, but it's going slow. Basically, when I use epoxy putty on other projects I put whatever is left over onto the styrene skeleton I built. I finally filled in the main sections (I will have a styrene cover for the engine section) and started sanding down to the level of the styrene. It's slow going, because you don't want to sand into the skeleton but you still have to have symmetry and the right shape. Once I get this part done, the rest will be a lot quicker.

[spejic]

I've put the wing on and put in putty to smooth the surface. I am also working on the intake - it is constructed by putting in plastic sides (which go all the way down but were later covered with epoxy), a thick plastic ceiling, and sanded into the rounded shape.



I still have shaping around the engine to do. Then I need to prime it and go after the surface with putty again. It's really hard to get a smooth surface. It's only after the sanding and shaping that I can put in the booms and tail and the rest of the aircraft.

[spejic]

I finished the intake shape. I had to glue new plastic on the inside sides and sand in because the intake face is not as wide as the fuselage. I wasn't happy with the overall shape, so I did a lot of sanding and now it's much more rounded in cross section than before. I did more surface work, and cleaned up the join between the wing and fuselage. I also engraved lines to indicate the wing control surfaces. After I was happy with all that, I put on the booms.



Next is the propeller shaft and digging out the nose landing gear well.

This post has been edited by spejic: 10 November 2011 - 08:56 AM

[spejic]

I created the nose gear well, put in the propeller shaft and engine hollow, and created and added the stabilizer. The graceful shape and balance of the actual aircraft is starting to show up.



Next are the various bumps and scoops and the landing gear. I don't have any spare wheels of the right size, so I will have to make some. Yet another thing I need to figure out.

[spejic]

I've added the bump on the top and the engine scoop on the bottom and blended them in. I've added the bottom stabilizers on the tails and added the bumps on them that the later flying version of the Sky-Y had (it's supposed to be asymmetrical).

The main landing gear was cut from the top from a can of Spam. I tried using frame from various photoetch sets, but they just weren't thick or strong enough. The front wheel was made out of a slice of tube that was sanded to shape with a plastic rod in the center to make the indented hub shape. I didn't have a rod for the main wheels, so I sliced and drilled out the center of some sprue (it took a while to find - most sprue isn't perfectly round)

I also engraved new control surfaces for the wings to match the configuration of the flight version.





Next is making the propeller and painting.

[FlyingLow]

Hi Spejic,

only now I noticed this project (I am not going into Group Builds sections much)... very nicely done so far, it promises to be another award winning model

[spejic]

 FlyingLow, on 30 November 2011 - 07:23 PM, said:

Hi Spejic,

only now I noticed this project (I am not going into Group Builds sections much)... very nicely done so far, it promises to be another award winning model

The only reason I thought I could do this was because I was inspired by your Sopwith Camel.

[spejic]

I added the bumps on the nose and details to the front landing gear. The probe is stretched over a flame to get the tapered look. I've been doing the paint/see flaws/sand/paint loop a thousand times and I'm still not done with that. Most of the pictures I've been working with are from the starboard side, and I just found out there is a vent on the port side of the engine intake. I think it's a little late to add it.

I tried multiple methods for making the propeller. The one I was happy with was taking some .030 styrene rod and sanding it mostly flat but keeping the hub end round.

Here's what it looks like now:



The paint is still splotchy in real life. And I still have to sand down the sides again. Only two weeks left...

[drhornii]

Down to the wire....almost there! Looking good

[spejic]

I've gone backwards a bit. It turns out the rough spots were bits of putty that didn't cure properly, probably because I didn't mix it well enough. I tried to sand or smash down or cut down those spots, but it turns out nothing works. So I dug out all the spots and put in new putty. It'll take a day or so to cure in the cold weather here.

Hopefully I will have enough time after I fix this.

[Eri]

WOW. Very nice, its like a Heron of the IAF

[drhornii]

The finish line is close....looking perfect as usual!

[spejic]

It'll take me a few more weeks at least. I'll keep the thread updated even after the GB is over.

I've bumped off the main probe so many times it could no longer be glued back on, so I made a new probe and drilled out the old stump. The new one is thinner, so hopefully it will bend more as I try in vain to cover it in enough coats of white. I also need to get some better decal paper.

[spejic]

Still working. I did add that intake on the side of the really big intake. Took a long time to get the white looking right. But I finally did, and in the last few days I masked the aircraft and painted the red parts. The writing on the bottom was masked off with tape.

I added the wheels and did some of the detail painting (headlights, front gear). I still need some more detail painting. The props are painted, but I need the white tips.

The decals are designed, but for some reason my new black ink cartridge is streaking badly when drawing on glossy surfaces. I have to figure out what is going on before I can print the decals.