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Woodstock

The Italian Job: Graecalis Aerobatic Glider

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Woodstock

I am a lucky recipient of one of the first (I think it may be THE first) "craft kits" of this model to be built (and hopefully flown) outside of Italy, so I thought a build thread may be warranted.

So, some background: a group of Italian enthusiasts by the names of Giammarco, Stefano and ? (please help me guys, I get a bit mixed up who is who in the zoo!) decided to design and build a new aerobatic machine with a wingspan of just under 4 m. The design brief was to go for a look that was a bit different to current models, and, of course, great performance. 

To this latter end, a dedicated airfoil was designed for this project by Claudio Becchetti, he calls this foil "BEX 1809". Even though I'm no expert on foil design, I do know that the foil is key to a gliders' performance. Claudio emailed me this explanation: "an evolution of the famous RG15. Camber 1.8 to 48%, and thickness 9% to 28%. The RG has the least resistance to the natural profile but worsens with negative flap. The profile that I obtained, as well as more efficient RG, has a better performance in inverted flight, with the advantage of being able to decrease the resistance with very -2 ° of flaps allowing an acceleration that the RG does not have." That was enough to convince me :) !


Specs are:

wingspan: 380cm
fuselage length: 209cm
wing loading: 90g/dm2
weight: 8,5kg

You may notice that is one HUGE fuz :blink: ! I fell in love with the design of particularly the fuz, as it has a graceful curved underside, and a spectacular canopy that goes all the way back to the wing joiner position. The tailfeathers are a bit different to the norm in that, instead of the rather ubiquitous all-moving elevator with a cut-out for the rudder, the curvy rudder is instead given a prominent cut out to allow for the elevator on the fixed tailplane to move. More curves there than Sofia Loren (am I showing my age  :unsure: ?)!


The initial steps of manufacturing my model in Italy (and more background) can be seen here: http://www.rcgroups.com/forums/showt...light=greacali. For even more background, have a look here: http://www.voloinpendio.it/ .

My building always takes forever, so this isn't going to be finished soon, but I thought I had better start getting the photos that I have taken so far published...

Hope it'll prove interesting  :) !


 

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Shedofdread

They look stunning and appear to go very well too so we're all expecting great things here... No pressure, you understand ;)

 

Will it be ready for the Kerry 'do'..?

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Woodstock

While I blithely ignore the previous post <_<, I'll post some images of the original designs:

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isoaritfirst

So how is it progressing Chris?

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Gromit

Very much lookin forward to following the build of this beauty & your progress with it Chris B) . Mmmm Sofia Loren :drool:

 

  Stu.  .

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oipigface

Sophia is coming my way soon.

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RGPuk

A very good set of eyes have worked on the proportions and details of that lovely machine.

Very lust worthy indeed.

Ro.

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Buzz

Beautiful and purposeful looking design, I will be watching your build with interest Chris. 

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simonslim

Sometimes, not very often though, you see a non-scale plane that definitely deserves a full-size replica and this has got to be one of those. I love the shape of the MDM-1 Fox but this Graecalis knocks the socks off the Fox in the looks department.

Watching with loads of interest and a new hidden fund started. :thumbsup:

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Woodstock

So how is it progressing Chris?

I'll be doing a (slow) build log here Mike....

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Woodstock

The serious stuff started with the arrival of the biggest darn box I've ever received! 

The "craft kit" consists of the main components only: Fiberglass fuselage (not "finish painted" in the mold: you are expected to finish and paint the fuz yourself); wings, rudder and tailplane in foam with "Tanganyika" timber veneer, clear canopy; canopy base; some fuz reinforcing formers, and a rudder top piece (more on the rudder later). I had the control surfaces hinged with peelply: there are various options you can ask for. The surfaces were all cut and ready to rock 'n roll.

The foam /veneer canopy base supplied to me has now been superseded with a moulded 'glass base incorporating a "seat" and "instrument panel" bumps. One is on it's way to me...

I elected (after advice from Giammarco and Stefano) to go for a wing joiner system consisting of two traditional standard brass boxes and steel blades. These were sourced in Italy and supplied for me for extra. I could have opted for round steel or carbon joiners instead. The wings come with timber cassettes installed to receive the brass boxes. These are already tied into the main spars.

There is no wing fairing on the fuz: I will have to match the wing roots to the fuz in due course.

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Woodstock

My chosen colour scheme for the Greacalis is a Red Bull skeme.  Sadly, after buying the decals already, I now see it's suddenly becoming hideously popular - oh well, should still look good I hope :unsure: . 

 

The photos are for illustration purposes only, and show a not-too-dissimilar model, the 3.7 m w/s Cornia Byphon, also of Italian design and manufacture (Giulio Cornia is a hugely productive designer and kit manufacturer: the Byphon can be bought as a full wood kit - built up with ply and balsa parts ; with a ‘glass fuz instead of wood; and even with a glass fuz and foam / veneer wings.  Rumour also has it that a very well-known Italian manufacturer of fully-moulded models will be producing the Byphon as well.  See: http://www.corniaaeromodelli.com/ .

 

I will not be doing the white bulls on the underside, just the lettering, and I think I will be adding blue tips to the tops of the wings...

Decals were designed and printed / cut by CallieGraphics : http://www.callie-graphics.com/index.php.  Callie is a pleasure to work with.

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Greg Dakin

Looks fantastic Chris - really looking forward to seeing your project progress, and the fruits of labour!

Cheers,

Greg

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Woodstock

Thanks Greg  :) !

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Gromit

Chris, I think the Red Bull scheme will be a good choice & look very cool :drool: .Really lookin forward to seeing your Greacalis in 'Woodstocks Workshop" when we come over in a few weeks time B)

 

  Stu.

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Woodstock

So, to start the build I approached her from the back (er, should I re-phrase that  :rolleyes: )?


The Italian guys apparently painted their flying surfaces as well as the fuz. I have a reasonable painting set-up, but not really good enough for that much work, so I thought of using Oracover / Profilm instead. I decided to cover the stabilizer first to check it out, and I'm happy with the results (BTW I first tried HK covering film as it's WAY cheaper: NOT recommended at all  :angry:).


I fitted a ply block with a captured nut in the fuz tail to take a nylon screw to secure the stab, and fittted a wood dowel as a locating pin at the front of the stab.

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Woodstock

The idea is to clad the ply top piece of the rudder with balsa after the slot for the hinge rod has been constructed. I was a bit concerned about the strength of the front "balance" part of the rudder: once the ply is grooved it is structurally in 2 pieces, and I'm not sure how strong it will be being held together with balsa only. For that reason I reinforced the piece with ply sections on each side of the hinge slot (before then cladding with balsa).

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Woodstock

next pic.

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oipigface

I am watching with interest, Chris.

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Woodstock

More rudder work.  A heavy rudder is a drag, so I did some lightening.

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