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Old Mar 19, 2010, 05:58 PM
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Gary,

I realize some info is missing from the plan, so I still have a few questions about some settings: normally, with this type of gyro, I would expect the neutral setting of the rotor head to be a couple degrees or so, to the right (pilot's view). Is this what you have on yours? Also, the movements on the head, any idea how many degrees l/r?
If you hold the whole gyro at the top of the rotor shaft, is the shaft vertical? Or maybe even slightly past the vertical, i.e. more nose-down?

Willem
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Old Mar 19, 2010, 06:48 PM
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Hi Willem!

My AG-3 hangs just a bit past vertical (nose down), maybe 3 degrees. The tilt on the rotor is 15 degrees left and right which I find a bit too sensitive. I often over-control the roll axis, even with 60% expo. I may cut that down to about 10 degrees left and right. The neutral point of the rotor tilt is about 2 degrees right (aircraft's right), which puts the rotor hub just about dead center above the mast.

Have you flown yours yet? Hope you get some nice weather for it!

Gary
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Old Mar 20, 2010, 08:36 AM
IAD
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I just put one of these together last night (with the 40" two-blade rotor), and did a bit of test-flying today... Looked really neat in the air, and overall, things went quite well, I was able to ROG and fly a few circuits. Yaw response was very good, pitch was OK, and most of the time, roll was solid, with no noticeable tendency to roll over to a particular side. (I'm using a CW rotor.) However, I was getting a roll lockout (no roll response) at roll angles of ~35 deg, which prevented recovery. (The pitch/roll gyroscopic coupling got me in trouble a few times.) I'd end up hitting the ground relatively level, but stuck in a rolled orientation.

I've got at least +/-15 deg. travel on the rotor tilt, probably a bit more.

Any thoughts?

~Luke

P.S. It just occurred to me that it's possible my roll pushrod was flexing. That would explain a lot. Also, I'll get a better picture once I fix it up a bit; right now it's a little beat up.
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Old Mar 20, 2010, 12:26 PM
IAD
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Looks like it was a pushrod issue, took a few short hops with a 2mm carbon pushrod and it seems much more responsive. I've also noticed my fuselage profile is a little too 'lifty'... I added some fillets here and there, and I think I must have overdone it. On my last few flights the wind picked up and I got blown around a bit; I noticed the aircraft seemed perfectly happy doing near-knife-edge 'flight' [falling] with the rotor almost unloaded. Overall, though, it seemed to handle the rough air pretty well for such a draggy airframe.

~Luke
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Old Mar 20, 2010, 05:19 PM
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Maiden flight in No Fly conditions

Went to the flying club this afternoon. Took the gyro with me, but I really knew the weather was way too rough for anything with a light wing loading. So, after a cup of coffee I went outside with my AG3, ignoring warnings of fellow club members. It probably was a longing for sensation, but everyone came out to watch. Very windy, very turbulent, 3 blade rotor spinning like mad, and off she went from a hand launch. To my surprise, the AG3 was totally controllable and didn't really need any trimming! Anyway, after a 2 minute flight I landed. What a success!
An hour later, after setting up the combi switch (rotor tilt coupled to rudder) I had another go. This gyro is quite spectacular in that it is so neutral, and so easy to fly. Did a couple of loopings too! Unfortunately there was no video camera available. Waiting now for the wind to lie down and feel what she's like in quiet conditions, and to try out the large 2-blade rotor. Maybe tomorrow???
C of G is like Gary suggested, with a hang angle of roughly -3 degrees. Sideways tilt is now at some 8 degrees each way, coupled to a rudder movement of 30 mm each way. Put 60 % expo in.
On the first flight I had much more sideways tilt and found that it is possible to over-control, the AG3 will then suddenly bank 90 degrees and lose much altitude while recovering. So, go easy on the rotor tilt, 7 or 8 degrees is OK.

Willem
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Old Mar 21, 2010, 01:39 PM
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LED in rotor blade

Gary,

Did you use a high intensity LED in your 2-blade rotor? Can you show a close-up of how you put it in the rotor blade?

Willem
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Old Mar 21, 2010, 04:03 PM
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Willem,

Congratulations on your successful gyro maiden!

Yes, my two-blade rotor has an 18000 mcd 5mm high-intensity LED...

http://www.superbrightleds.com/cgi-b...sp=%2Fleds.htm

...embedded in one tip. The battery is on the other blade, much closer to the hub, so it will balance. Here are some pictures. The 3v watch battery is an Energizer 1008, but I imaging any large 3v watch type will work. I traced the LED outline onto the blade, cut a hole to match it, and laid the LED in the hole. It is secured with hot glue (low temp), and Scotch tape. The + and - leads on the LED are on opposite sides of the blade. Magnets are used as a switch on the battery.

Happy flying!

Gary
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Old Mar 21, 2010, 05:30 PM
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Magnet switch... Brilliant!!!

Coming Sunday we have our last indoor flying session of the season. I expect to see 2 or 3 AG3s (including mine) there!
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Old Mar 22, 2010, 03:47 PM
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Gary,

While sketching around a bit to lower the tail fin to create more room for the rotor blades I ended up with a somewhat different fuselage. It is entirely blueprinted on your original AG3.
Now, where can I find some spare time to build this version...
Hope you like it!
Instead of the radial engine drawing on the plan you can use any good photograph or drawing of a radial engine of your own choice, scale it down to 10 cm or 4".

Willem
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Old Mar 22, 2010, 09:38 PM
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AG3 with a twist

Willem II,
That is cool what you done with this great design. I seems the AG3 lends itself pretty well to mods (at leat in looks so far for me). I myself have been sketching some cosmetical changes on the AG3 too. I have been out of work for awhile and so my building has all but stopped. So I do alot of drawing on future projects that I would like to do once I get back to work. Cheers!
~Vrated
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Last edited by Vrated; Mar 23, 2010 at 11:07 AM.
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Old Mar 22, 2010, 11:23 PM
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Vrated,

Those are some really neat designs! I particularly like the second one, very nice lines! I must build that version too, I reckon .

Once a year we have a depron weekend at our club. Club furnishes depron and glue, members bring their own hardware. We build at the club, and the model must be finished by the end of the session. Last year it was STCs, Piper Cubs and the F-16, all very simple '+'fuselage models.
Some members already have said they'd like to do the AG3 this year. So now it looks like they'll have at least 3 models based on one design to chose from!

Willem
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Old Mar 23, 2010, 08:51 AM
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Willem II,
The Club sponsered Depron build sounds like a lot of fun. I have a few more variations somewhere, I will have to see if I can locate them. If you guys are interested I can put together a PDF file for the second sketch. The second sketch is not my original design BTW, I just incororated the "Tiberon" 3d biplane lines into the AG3 layout. I did make all the tail surface areas the same as the original AG3 though.
Cheers!
~Vrated
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Old Mar 23, 2010, 09:18 AM
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Got all the materials together in December to start building mine. Still haven't. I have drawn up an elevon tail to try too that I posted somewhere, couldn't find it today.

I am also still planning to do this apache gyro from over in the scratchbuilt forum as well. It is not a dc head, but uses an interesting rotor that doesn't change directions when inverted. http://www.rcgroups.com/forums/showthread.php?t=1175516
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Old Mar 23, 2010, 07:45 PM
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Just about finished building my second airframe... Some modifications here and there, like Willem, I decided to lower the vertical stabilizer a bit, and I reinforced the front end. I also removed the lower part of the fuselage, to reduce the knife-edge floating... Also substituted a 1/32" plywood plate for the Depron hub... (The hub in the picture is carbon-reinforced; I'll probably remove the CF, as it made it a little too stiff for my taste.) Lastly, I added a full-flying stabilizer, just for the sake of it.

Test-flights tomorrow, weather permitting..!

~Luke
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Old Mar 26, 2010, 05:59 AM
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Vrated,

I've extracted the DXF from your pdf file, so that I can print the patterns to the same size as the original AG3. Too busy with work, but somone in our club is going to build it. We'll keep you informed on that.


~Luke,

I like the rectangular hub on yours! I think the 2-blade rotor is harder to align than a 3- or 4-blade, or at least more sensitive to alignment related vibrations.
If one makes the hub plate the same width as the rotor blade plus carbon rod, the whole rotor can be aligned against a wooden block, a piece of angle iron, or whatever...

Willem
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