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Old Nov 18, 2012, 11:52 AM
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Belgium, Flemish Region, Duffel
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Jamara Siai Marchetti SF-260 build

I have been looking for a model of the Siai Marchetti SF-260 for a while, and I found a nice lasercut kit of Jamara for this.
I want to make it in the Sabena flight school livery:

After all the foamies, I felt it was time to get me some balsa :-)
I had been working for weeks on a foamie, but I got a bit tired of it; it's just not the same feeling.
I started the build yesterday, and I am very pleased with the quality of the kit : good cutting, good fit of the parts. Only the manual can be a bit unclear at times, and one needs to use common sense to find the right parts.
I will be equipping it with retracts, and I am wondering whether it would be a good idea to add flaps to it. I will be operating it from a grass field with quite some limitations that sometimes force you to make the final turn at only a few meters in front of you, at pretty low altitude. In those cases it might be a bit more comfortable to slow it down....
As the pictures show, I started with the fuselage, and it is slowly starting to look like an airplane....
To assemble the wing, I need to find a method to fix everything at the correct angle before I start to glue things together. And I need to decide on the flaps before I can do so...
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Old Nov 18, 2012, 01:46 PM
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Phaedra's Avatar
Belgium, Flemish Region, Duffel
Joined Apr 2012
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For this model, I bought a Turnigy 2822/14 1450 kV motor.
According to eCalc, with a 8x4 prop this should give me 0,75:1 power to weight ratio. Recommended prop is 9x6, but eCalc states this would exceed the max current for this motor. I will try and measure this anyway.
Another problem I am having with this build, is fixing the parts while the glue sets.
I have read about magnetic jigs, does anyone know where I can find more information about those?
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Old Nov 22, 2012, 08:29 PM
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Nice. Were can I order one online?
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Old Nov 23, 2012, 01:23 AM
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Belgium, Flemish Region, Duffel
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If you search for Jamara Marchetti sf-260 lasercut, or it might be marketed under the Balsaworx brand in the US, I'm not sure about that.
In Europe there are plenty of stores that have it in stock.
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Old Nov 25, 2012, 12:03 PM
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Phaedra's Avatar
Belgium, Flemish Region, Duffel
Joined Apr 2012
625 Posts
Little progress in the build, due to high workload from my job.
The fuselage got some stringers, while I clamped it with some heavy objects to keep it straight while the glue set.
The easy, standard part of the build is done, now the customising can start.
After building up the basic structure of one wing, I need to investigate how and where to install the retracts and flaps.
I got some nice scale struts from Hobbyking, but they would come out too long when I use them as they are. In the pictures you can see how I intend to do that by making a connecting piece twice as long, so the strut would "kneel" a bit more, which also corresponds more to the real landing gear. Don't know yet how I'm going to do that....
Now things start to get really interesting :-)
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Old Nov 26, 2012, 01:16 PM
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Belgium, Flemish Region, Duffel
Joined Apr 2012
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With a bit of tinkering and tweaking, I made some advance with the landing gear.
I had to solve different problems:
  1. As I explained in the previous post, the gear legs needed to be shortened. I did this by fabricating a replacement connecting part of twice the original length, so the gear would "kneel" more
  2. In the E-flite retracts, the axle comes out flush with the servo motor housing, requiring an axis-shift to be able to fit the struts
I managed to create a first trial for the connecting part, still very rough, but this can be ground down to a nice shape with rounded edges.
With the help of my neighbour, I was able to bend a 3mm steel wire to get the required axis shift. It isn't perfect, but it's the best I can manage with the tools I have. It would be better if I could get the struts closer to the housing when the gear is up, because now I'm afraid they will still stick out. I might solve that with slightly bent gear doors if I don't find a better solution.
Next step is to make the necessary cuts in the wing ribs, to house the retracts, struts and wheels.
Wish me luck....
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Old Dec 17, 2012, 08:53 AM
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Hi Phaedra,

I just opened the box on my SF260 today!

Which retracts did you go for?

thanks

rich
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Old Dec 17, 2012, 10:47 AM
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Can you advise which stores have these in stock? And have the contact info for the store.
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Old Dec 17, 2012, 11:03 AM
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Belgium, Flemish Region, Duffel
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I used the e-flite 10-15 retracts, which only just fit inside the very thin wing.
Had to forget about the struts and use the standard eflite ones, because otherwist the main gear comes out too long. I figure the struts will be covered by gear doors anyway...
Meanwhile I haven't made much progress.
I cut out flaps in one wing, and built up the structure for the other wing. Very busy period at work, hopefully I can continue soon.
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Old Dec 17, 2012, 11:09 AM
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Phaedra, OK thanks - will take a look at these.
I just got started today, got the two spars glued and the ribs are prepared. I have a few weeks off work so hopefully can make some progress.

I have an e-flite power10 outrunner I intend to use which should give some decent performance I hope

cheers

rich

Flyinucrazy - I bought mine from Germany via e-bay, here http://www.ebay.at/itm/ws/eBayISAPI....m=170949018182
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Old Dec 17, 2012, 02:30 PM
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Will you be adding flaps?
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Old Dec 17, 2012, 02:54 PM
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have not thought about it - probably try and avoid the complexity although it looks like it might be quite slippery and difficult to slow down.
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Old Dec 18, 2012, 01:40 AM
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Phaedra's Avatar
Belgium, Flemish Region, Duffel
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I was thinking exactly the same, given its thin wing profile...
I will not be home this evening, but I will do my best to post some pictures of how I did the flaps as soon as I can.
Problem is that the ailerons are a bit long to be scale, so there isn't much trailing edge of the wing left for flaps.
I'm not quite happy with the result I got, maybe I will still modify it.
Don't know what type of hinges I will be using for the flaps, offset or normal. If I put normal hinges at the bottom, I'm afraid the flaps will generate a bit too much turbulence at full deflection (and thus drag). If I use offset hinges, I can create a bit of a fowler flap effect, which it might need considering the small flaps surface.
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Old Dec 18, 2012, 02:18 AM
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Did you consider flaperons?

if the ailerons take up most of the trailing edge maybe that is an option? I have never used them myself so do not know the details but in principle......

I think I will build without flaps for now. This is the first build like this I have done so I think I will keep it relatively simple.

The retracts are adding complexity for me as I have never dealt with them before so one step at a time!!

The area where I fly is pretty open so landing length is not really an issue, just need plenty of time to slow her down.
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Old Dec 18, 2012, 02:05 PM
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Not quite an SF260 but close.....

http://www.facebook.com/photo.php?fb...type=1&theater
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