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Old Nov 04, 2012, 07:27 AM
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Well going to maiden mine today. Wish me luck! Just going to fly it on the recommended low rates first to get a feel for it and get it trimmed out.

Robert
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Old Nov 04, 2012, 07:49 AM
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Originally Posted by kingconsulting View Post
Well going to maiden mine today. Wish me luck! Just going to fly it on the recommended low rates first to get a feel for it and get it trimmed out.

Robert
Good luck!

What expo are you running?
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Old Nov 04, 2012, 02:13 PM
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Well did the maiden today...Flew great!

Needed a few clicks of up elevator and one click right aileron and flew pretty good. Second flight I moved the battery back about an 1/8th of an inch and it flew a lot more level. Even had my hands off it a couple times. Did 4 flights. By the second flight I was doing rolls, loops, snap rolls etc. and I've never done snap rolls before in a real plane.

Probably my favorite plane now. Need to try the other prop (12 x 6) for comparison just for fun.

Oh I never used expo before but did on this. Used 40% all around except for the rudder which was 50%. Got that from that AJ video.

Will need to do some adjusting as I go but very happy with it today! If I can get the video from my son I will. Not sure on the quality yet

Robert
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Old Nov 05, 2012, 08:53 AM
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Well I took what I could from my sons phone and cut out a lot. It was a little chilly that morning and he was wearing shorts and shivering

So first flight was right about 6 minutes and I had 47% left on the battery but I wasn't doing too much on the first flight. By the fourth flight about the same time I had 27%.

I usually set the timer about 5 minutes. That gives me a little wiggle room.

Robert

3DHS Osiris 47 Maiden (2 min 32 sec)
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Old Nov 07, 2012, 09:50 AM
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Originally Posted by kingconsulting View Post
Well I took what I could from my sons phone and cut out a lot. It was a little chilly that morning and he was wearing shorts and shivering

So first flight was right about 6 minutes and I had 47% left on the battery but I wasn't doing too much on the first flight. By the fourth flight about the same time I had 27%.

I usually set the timer about 5 minutes. That gives me a little wiggle room.

Robert

http://www.youtube.com/watch?v=9KkxFkiBXQM
shivering in California?
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Old Nov 07, 2012, 02:56 PM
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Well it was 54 degrees you know You guys just don't know what REAL weather is like haha

I'll admit it my kids are wimps when it comes to weather!

Robert

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shivering in California?
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Old Nov 08, 2012, 04:42 PM
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I think there is something wrong with the suggested CG range for the 47" Osiris. Even the most aft recommended (125mm) is a static margin of about 20%. I found it has requires too much down elevator inverted with the CG there, and drops the nose too quickly on an inverted 45 degree up-line.

I recently got a 62" Osiris, and the manual and the thread here both suggest a CG 7" back from the wing LE/fuse junction is best for pattern flying. I calculate a static margin of 6% with the CG there. So far I like the way the 62" one flies with the CG at 6% SM.

I calculate the 6% SM CG location on the 47" Osiris would be about 158mm back from wing LE/fuse junction. I like the way it flies better back in that area. I have flown with the CG back as far as 165mm so far. That is a long way out of the recommended range. It flies very nicely there, but of course the elevator throw must be reduced considerably, preferably mechanically. I'm have the pushrod on the inside hole on a Hitec HS65 servo arm.

I wonder why there is such a huge difference in the recommended CG positions, when the planforms are essentially identical, just scaled?

Kevin
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Old Nov 08, 2012, 09:32 PM
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Partly, because you can scale the plane but not the air molecules. You can't make a plane bigger/smaller and expect it to fly like it used to. Personally, AJ's (and Scott's) recommendations are quite a bit more forward than I prefer to fly.
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Old Nov 09, 2012, 12:09 PM
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I made a mistake in the sweep on the 62" Osiris. The 7" CG position is actually an 11% static margin. The equivalent point on the 47" Osiris would be about 146mm back from the wing LE/fuse junction.

Stability, unless there are severe low Re effects and poor airfoils with very non-linear lift curves, is not really affected by scaling. My calculated neutral point for the 47" Osiris seems to be very close from flight testing. With the CG back to 165mm it is still reasonably pitch stable.

I am a bit surprised that these airplanes are being flown with even an 11% static margin. That would be considered very pitch stable in the sailplane world. Re effects do start to come into play on the stability of sailplanes at the low speeds they can fly at, but even so the effects are usually quite small with decent airfoils.

I suppose there are certain compromises in the CG position to get the knife edge behaviour correct for pattern airplanes.

Kevin
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Old Nov 09, 2012, 03:55 PM
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My first flight was at 117mm and had to move the battery back about an 1/8th inch. Next time I will be experimenting a little more with the CG.

Had a little wind for both days so waiting for a day to trim it better.

Just bought a couple more batteries and another charger. Really love this plane got a lot of nice compliments on how well it flew and one guy wanted to trade me for it

Robert
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Old Nov 23, 2012, 09:00 PM
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Marietta GA.
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Guys, mine was flying good until I got into a esc/motor funk.. Too make a long story short I sent a esc back to Castle for warranty, but I`m pretty sure its my Omega motor..It worked fine on a Hacker esc so that messed me up trying to figure out the problem.The magnets have comes loose on the omega..Does the torque and hacker just bolt up with the same cowl spacing? I`m kinda thinking 3DHS should warranty the omega , but I took it apart to try and fix it so shame on me.
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Old Nov 23, 2012, 09:04 PM
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I'd call 3D they are good people. My Hacker sticks out in front of the cowl by ~3/8"
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Old Nov 24, 2012, 01:47 PM
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After fooling with the Omega for a bit...I had a Turnigy 3536-1100 lying around..This thing bolts right up...It was a touch shorter so I used the X-mount off the Omega as a spacer..This 18.00 dollar motor works just as well as the Omega..I couldn`t tell any difference in speed or run time..For a guy looking for a cheap motor for one of these, its perfect..I`m still gonna get another Omega or maybe a Hacker...jason
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Old Nov 25, 2012, 09:56 AM
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Guys, after going through the forum it looks like the Omega is about 45mm from x-mount to prop adapter...It seems the Hacker is 51mm and thats why the cowl must be moved so far foward...Anybody have a dimension for the Torque motor? or is it the same as the Hacker?
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Old Nov 25, 2012, 11:56 AM
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I have seen an installation where a hole the diameter of the motor was cut through the firewall, and the motor mount screwed to the back of the firewall, instead of the front. That moves the motor back most of the difference in length.

Kevin
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