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Old Jul 24, 2012, 08:44 PM
ROV Pilot
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Norway
Joined May 2002
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Waiting for a E Strega, is 110mm the optimum CG?
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Old Jul 25, 2012, 02:55 AM
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Since I've flown my so little, all I can say is that 110 is well balanced, not to aft,
and feel responsive. I have read some people liking it at 113, and others thinking
moving a little foreward from that. I think 110mm is good to start with.

Strega F3F Light DS Morvikfjellet (4 min 51 sec)


Predator & Strega @ Salhusfjellet (5 min 36 sec)
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Old Nov 30, 2012, 09:04 AM
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New Strega in progress

I got a second Strega model to prepare. I crashed the first, not beyond repair, but have not motivation to do the reparation now, it's a spare now for simular incidents later.

However, this Strega is being modified to carry wing and possible joiner ballast as well. Also I am up scaling the fuselage ballast tube from previous 22mm slugs, to 24mm slugs. It will fit just nice, the only limit, is that I am in doubt if the wiring will be possible to fit under the servotray next to the ballast tube on each side.

With my new configuration, the weight in the fuse is now 1700grams.

In the wings I have brass 700 grams, to the 20x10mm rectangular tubes supplied by sloperacer. But the brass supplied were very loose in the tube, so I am planning to mould 20x10mm lead slugs by using silicone mould mass to make the forms from a 20x10mm wood list. That should give approximate 1000 grams in the wings. I now have two joiners, and I have filled one with lead beads adding another 400 grams. The cutout job for the holes for the wing tube were easy, and the tubes will now be glued into the bottom of the wingsskin, and one side facing to the spar, behind the joiner box. The Cg will be placed at 112mm when glued in behind the joiner box, a little to aft after my taste, so possible some joiner ballst is the solution.

That would sum up to a total of 3100grams available ballast.

Most likely I should be able to fly the wings of the fuselage with this weight in some fast EM turns.

The motivation to do the wing ballast modification, is that I have got my hands into a Skymax 4 which have 24mm slugs in the fuselage. And for not having to carry different sets of ballast, I needed to make it possible to bring two planes to the slope, but just one ballast set.

Also I am convinced the more weight carried in the wings, will maintain the crisp handling on the elevator on the Strega, compare to having a long sausage of lead in the fuselage. I think 1400 grams in the wings+ some extra in the fuse will be just perfect. I am hoping to have it ready within early spring.
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Old Dec 01, 2012, 02:00 AM
Thermal Wrangler
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Launceston Tasmania
Joined Mar 2004
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You're gonna make the earth wobble with all that lead. Be my guest ;0)
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Old Dec 01, 2012, 03:57 PM
isoaritfirst
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Not a Brummie/but close
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Have you checked what the FIA weight limit will be on that model.

I also hope that the wings are much better made these days than the earlier ones. Mine used to get very twisty at anything sub 40.
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Old Dec 01, 2012, 04:33 PM
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I am not planning to put in more than 1600 grams in it.

I have flown the Strega with 2kg, and the wings became alive.

So I am not ignorant to limitations of the Strega.

Just as much as possible of that weigh in the wings.
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Old Dec 22, 2012, 02:22 PM
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The second Strega build have moved a bit foreward. I decided to leave the fuselage ballast out of the equation for this build. The wing tubes are glued in
and the plane wil still take 1700 grams of lead in wings tubes and joiner tubes.

Wood plugs for moulding lead slug have been prepared. A form will be prepared in silicone mould mass, that can withstand 450 degress celsius (and molten lead).

A long servrotray was prepared, 43cm long, actually it can be seen half through the joiner hole. It is my hope that the long servotray could make this model survive the harder landings, and the nose is always a weak spot were it breaks first. The tray is prepared for Futaba S9650 or S9071SB servos.

On the other hand, I worry that I only move the breaking to under the middle of the wing, were a repair will be much harder. Time will show.

I am aslo planning to have two strips of carbon rowing in the canopy opening, and two strips in the lower fuselage inside the opening as far as I can reach it.
To bad it was not done at the factory as the newest versions have.

Some very nice aluminium servoframes from Windrider were bought in for this. Even though not mounted, this ball bearing frame feels like real quality, and to add to this, I prepared some extra spars to be put inside the servoarm for each wingservo, so there is no chance the wings sking moves / give in, when the servo is stressed with forces. A 15mm wide balsasheet was used, laminated with 160grams carbon, and another layer of glass 120 grams (?), with standing balsa. It seems quite solid. Hopefully these two enhancement will give precise on look tight control surfaces, that is the plan anyway.

I have attached some pics below.
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Old Feb 13, 2013, 07:29 AM
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Fuselage preparation

The servo tray has been glued in. A nosejob was given to the Strega, two layers of 120 grams glass cloth did the difference. Together with the long servotray, the nose is quite stiff, and hopefully much stronger than original.
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Old Feb 15, 2013, 09:20 PM
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Australia, VIC, Croydon
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Quote:
Originally Posted by jijohans View Post
Waiting for a E Strega, is 110mm the optimum CG?
Just found this thread ----answer NO

For Electric Strega !00/105mm would be more appropriate

Regards Keith
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Old Feb 23, 2013, 10:21 AM
Impatience is a virtue
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Denver, Colorado
Joined Nov 2008
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FWIW, my Strega is at 114 - flys great
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Old Feb 24, 2013, 10:47 PM
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Quote:
Originally Posted by MCH27t View Post
FWIW, my Strega is at 114 - flys great
What is your AUW

Regards Keith
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Old Feb 24, 2013, 10:52 PM
Now Compressing Air
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United States, CA, Thousand Oaks
Joined Jan 2010
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Looking very nice krvedaa.

GS
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Old May 02, 2013, 02:37 PM
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Modified Strega with only wing/joiner ballast (1640 grams)ready for maiden.

Waiting for the right day with good conditions. Cg at 109mm, ready weight 2250 grams.
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Old May 07, 2013, 12:53 AM
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Strega first flight

Strega first flight Golten (3 min 10 sec)
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