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Old Apr 14, 2008, 03:36 PM
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Germany
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Quote:
Originally Posted by Rare Bear
CS - thanks for that info! That's exactly what I wanted to hear, and lengthening the wires will make this build exceptionally easier & quicker. Appreciate the info!

Here's a question for anyone willing to answer; I plan on using HS-81MG servos for the ailerons - have a set lying around, and I figure they would add a bit more weight towards the nose, considering this bird is a bit tail heavy. But, I have heard of a few desiring HS-65's all around, which I do have in hand - plan on using (1) for the tail, and I have (2) others waiting for another project. Anything I'm missing? Let me know - thanks!!


God bless - "Rare"

The HS 65 in the tail is not a bad idea, bcause its not so heavy as a HS81MG, but you will still need some additional weight(lead 4 example) in the nose to reach the correct CG, I think the siren is developed before the lipo age. I 've ordered some cells of A123, so I think with this cells its easier to reach the CG as with a lipo battery.


Wolfgang
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Old Apr 18, 2008, 03:27 AM
Isaiah 40:31
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Joined Mar 2006
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Wold, Andy, and Everyone Else - thanks for the info! Siren build is starting on Monday - I'll update pics and info when I can. Thanks again!


God bless - "Rare"
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Old Apr 19, 2008, 03:27 AM
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Joined Jul 2005
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Spektrum install

Hi,
a couple of people have asked me to see my setup of how I have my RX installed in the siren. Ive had it now for about 8months with this setup,without any glitches etc and have had it at over 1300+ feet with no signal loss.You can also see how the batteries are installed right up the front side by side,
no nose weight needed,just put some stop blocks to stop the batteries from rudding against the motor.
Ive also attached a dump for those that want to see what a 14 X 9 spinner with an axi 2826/10 draws. As you can see I flew for over 35mins,not full out all the time.
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Old Apr 19, 2008, 10:54 AM
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United States, UT, Ogden
Joined Nov 2004
629 Posts
Whats all this talk of lead in the nose? I fly my siren with an Axi 2826 10 and a TP 2070 Extreme - CG is "about" 100mm and it flys great, dive test shows a slight pull up and landings are a bit warm but easy.....
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Old Apr 19, 2008, 12:10 PM
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Germany
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Quote:
Originally Posted by asat
Whats all this talk of lead in the nose? I fly my siren with an Axi 2826 10 and a TP 2070 Extreme - CG is "about" 100mm and it flys great, dive test shows a slight pull up and landings are a bit warm but easy.....
ok, so you can be lucky, but its not possible to reach the recommended CG from the manual (about 55mm) without some additional weight in the nose, perhaps if you use a heavy geared inrunner like a kontronik etc. but with a axi like yours (and also mine 2826/12) there is no way, perhaps using two batterys, but with single battery....not for me
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Old Apr 19, 2008, 02:45 PM
Bad Gunkie
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USA, GA, Centerville
Joined Dec 2002
3,341 Posts
fwolf,
The CG in the manual is wrong. Read through this thread and the other on the Siren and you'll find that referenced many times.

Bill Davenport
AMA 28141


Quote:
Originally Posted by fwolf15
ok, so you can be lucky, but its not possible to reach the recommended CG from the manual (about 55mm) without some additional weight in the nose, perhaps if you use a heavy geared inrunner like a kontronik etc. but with a axi like yours (and also mine 2826/12) there is no way, perhaps using two batterys, but with single battery....not for me
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Old Apr 20, 2008, 07:40 AM
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Germany
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Quote:
Originally Posted by badbill
fwolf,
The CG in the manual is wrong. Read through this thread and the other on the Siren and you'll find that referenced many times.

Bill Davenport
AMA 28141

Ok, thats the reason why I've to put so much additional wieght in the nose, I've flewn mine with a CG of 60mm, so next time I try to go more back, in the thread I've found a recommended CG of >75mm.
I've checked the online manual today, there still the 55mm listed :-(
Sorry for the confusion.
Wolfgang
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Old Apr 24, 2008, 11:33 AM
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Wolf,

So how did she do setting the CG?

I'm looking to add one to my fleet. How bad would you say the tip stall is? Is it comp to others? Can you fly her pretty slow if you want?

Anyone can chime in on this one.

I'm looking for a good thermal sailplane that looks a bit sporty and can handle some speed. Not looking to break speed records...

Any help would be greatly appreciated.

John
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Old Apr 24, 2008, 11:35 AM
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Also,

Is the CF really paper thin? does anyone think it's stroger than a glass fuse?

John
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Old Apr 24, 2008, 01:30 PM
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Germany
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Quote:
Originally Posted by Jlundberg
Also,

Is the CF really paper thin? does anyone think it's stroger than a glass fuse?

John
the CF fuse is thin, not to compare with a glass fuse in thickness, at the nose behind the motor, its easy to push in the CF near the cooling slits.
Yesterday I have removed the preinstalled firewall, so if the firewall is not installed, the fuse is very weak and soft in the front area. So its important for the structure that the battery mount (plywood) inside the fuse is completey glued to the carbon, so this should be checked after rough landings.
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Old Apr 24, 2008, 02:07 PM
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Germany
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Quote:
Originally Posted by Jlundberg
Wolf,

So how did she do setting the CG?

I'm looking to add one to my fleet. How bad would you say the tip stall is? Is it comp to others? Can you fly her pretty slow if you want?

Anyone can chime in on this one.

I'm looking for a good thermal sailplane that looks a bit sporty and can handle some speed. Not looking to break speed records...

Any help would be greatly appreciated.

John
Hello John,

I can't compare the siren with a comparable model, it's my first model of this type. Before the siren I have got a MPX easyglider, made of EPP Foam. SO it's really not comparable... I think it's not a (pure) glider, and also not a hotliner, it's more like a mix of both, somebody called it warmliner, so i think this is the best description for it. I wouldn't buy it anymore, not because I think it's a bad plane, only that I've often problems with the one piece wing (2000mm), its not so easy to store or transport it. If you want a more thermal like glider, you should choice a model also with rudder, a simprop excel 3 for example.


Wolfgang
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Old Apr 24, 2008, 02:22 PM
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Great Info... Thanks.

I have a truck but I do like the thought of a 2 pc wing. How do you think she flys?

John
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Old Apr 24, 2008, 02:27 PM
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Germany
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Quote:
Originally Posted by Jlundberg
Great Info... Thanks.

I have a truck but I do like the thought of a 2 pc wing. How do you think she flys?

John
She flys well, but not recommended for a beginner.... compared to my easyglider she is much faster, and so the runway is getting often very short for landing.
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Old Apr 24, 2008, 05:14 PM
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Joined Nov 2004
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Only a beginner in Sailplanes not flying. Been doing that for a while now. I mostly have been into pattern, some 3d and helis.

Do you use spoilerons? This doesn't slow her down enough?

where is a good place to look for a simprop excel 3? I can't seem to find a location here in the states.

Thanks,

John
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Old Apr 25, 2008, 05:59 AM
RIP Ric
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Marietta, GA
Joined Jun 1999
43,312 Posts
Spoilerons don't slow the model much, they just help reduce the glide length..
..a
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