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Old Jul 28, 2015, 05:05 AM
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Quote:
Originally Posted by Ralf W. View Post

Btw, I flew the machine yesterday first with a 11x7 propeller and later changed to a 10x4,7 prop. It surprised me, that the flight duration (motor run time) was identical.
I had something similar happen with my rewound motor. The stock prop drew 17A at WOT (static testing), I expected a fair rise in the current with a 11x4.7 but it only drew 17.9A.
I don't really want to move up to a 12" prop & think around 25A is a good target so there is still some headroom. Might have to rewind it again & spin that 11x4.7 a bit quicker .
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Old Jul 28, 2015, 12:01 PM
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I'm running an APC 11x8 and it pulls 22A static. I upgraded my ESC to a 30A I had in the parts drawer. Seems to fly with good power. I'm interested in trying the 10x4.7 after reading folks results here.

Dennis
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Old Jul 31, 2015, 04:31 AM
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I couldn't find the product thread for the newer Durafly Auto-G2 gyrocopter, so thought I'd post this here. A video we made the other day of the Durafly Auto-G2 - unfortunately due to pilot error it crashed!

HobbyKing Durafly Auto G2 Gyrocopter - Takeoff & Crash (2 min 11 sec)
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Old Jul 31, 2015, 07:44 AM
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I meant to do that
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So I've crashed, repaired, bought new fuselage and crashed again. I'm thinking this thing is not my cup of tee. Before I post the unbroken parts on the classifieds let me ask...

If I post the following parts in the classifieds would there be interest?

Empanage is good.
Tail boom is good.
Rotor head and mast is good (G2 with pre-rotator)
Motor, ESC and motor mount are good.
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Old Jul 31, 2015, 01:08 PM
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JOHN 3:16
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Central Ohio
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Quote:
Originally Posted by eMoon View Post
If I post the following parts in the classifieds would there be interest?

Empanage is good.
Tail boom is good.
Rotor head and mast is good (G2 with pre-rotator)
Motor, ESC and motor mount are good.

If the "price is right" there will be interest...
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Old Yesterday, 04:57 PM
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From Auto-G to Otto-G

This morning I built a new head and new rotor blades for my Auto-G - inspired by and based on the ideas of MrTwister http://www.rcgroups.com/forums/showthread.php?t=1340511 and Otto http://www.rcgroups.com/forums/showthread.php?t=2440662. Using the same diameter for my new 4-bladed rotor as the original HK 3-blader, there was no need to change the tail surfaces or anything else on the Auto-G.

This afternoon, on our flying field, I tried to spin the head in the light wind for a hand launch. No chance?!? The rotor started to spin slowly but no chirping. So I abandoned the idea of a hand launch and tried a ROG into the very light wind. Again: No chance – the gyro rolled along the grass, accelerating slowly and the rotor head accelerated very, very slowly. Ok, bad luck, I thought, maybe the negative incidence of the blades is too small. And while I was still thinking about blade incidence angles, and before I could cut the throttle, the autogyro lifted into the air, slowly, majestically – and flew like a charm. The necessary rpm and the flying Speed of the 4-bladed head was / is much smaller than I was used to from the original 3-blader. I did not try aerobatics today. But for “normal” flight I can already recommend this rotor head! Big success Thanks!
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Old Yesterday, 05:32 PM
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Congratulations, Ralf !!! It's great to hear of your success. Someone should produce similar blades commercially, and make them available to the Auto-G crowd. My Otto Jr. copter flies at roughly 15-20 mph, straight and level at less than 1/2 throttle. In a 7 minute flight, I am only using 50% of my battery's capacity. These flat blades must not be as "draggy" as initially suspected. Incidentally, my blades don't "chirp", either. The blade tips must be traveling somewhat less than the speed of sound. I've seen a British Pathe autogyro newsreel clip from 1931, where it is stated that the rotor rpm (looked to be a PCA-2) was 130 RPM. In the soundtrack, you can hear the blades are producing more of a "whooshing" sound. Keep up the good work, man !!! Charlie
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Old Yesterday, 06:00 PM
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PS I used 1/32" ply (3/16" wide x 1 1/2" long) shims that are tack-glue to the bottom trailing edge of the ply blade spokes. That is, in between the GF and ply spokes, on the first 1 1/2" of the bottom ply pad area of the blades. The spin-up is so much easier with the shims, certainly at Otto's 38" diameter. So your rotor is now 33" dia. , Ralf ?? It will be cool to see video of your new blades in action.....I am stoked that others are catching on to this !!! I recall a Model Airplane News article from 1948 by Roy L. Clough, Jr., describing a rubber-band autogyro utilizing this rotor blade style !!! My successful Cox-powered free-flight gyros all used forms of this rotor.
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Old Today, 12:02 AM
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Well,

I have a question: Should a person not attempt to fly one of these Auto G2's when it is a hot day, with low density? Mine flew just fine the last time I flew, but today (pretty hot day) it took off, but I couldn't get it to gain altitude above about 10ft. After I made my first turn it just kept slowly dropping altitude till it basically landed itself. Only damage was to the main blades as it went down in tall grass. I checked the battery, and the motor pulled a solid 21A static. I'm running an APC 11x8 Eprop. As I said, it flew fine on several prior ocassions.

I'm still learning these things. Any Ideas?

Thanks,

Dennis
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Old Today, 02:47 AM
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@Charlie: I followed your suggestions from post #2370: “The tip weights should not be needed with a more rigid blade. ... Allow the hub or spoke to flex, rather than the blade. When I lift my model by the tip of the spokes, the blades flex up @ 10 degrees. Set yours up in the same manner, and the rotor should perform well. Best of luck in your experiments. Charlie“
My new rotor blades are completely flat. Diameter of the rotor: only 800mm (31 ,5”), 50mm chord, 3mm Depron. The leading edge is 3mm CF rod (because I had no 3mm CF tube handy), fixed with clear tape. No special tip weights at all.
I use 1 mm shims at the rotor hub, tilting the spoke and thus the whole blade at the 3 mm bolt. This can be seen on my second picture, if you enlarge it sufficiently. The spokes are made from a sandwich of 1 mm ply, 0,4 mm GF, and another strip of 1 mm ply. Width of each spoke is 16 mm. I started with only 1 ply spoke together with the GF strip, but this was much too flexible. Adding the second ply strip, the blades flex up @ 10 degrees, when I lift my model by the tip of the spokes.

I had to throw away my 1250mAh pack because it has one weak cell. Flight time was only about 2 min before the low voltage alarm beeped. I changed to a smaller battery, 850mah, 70gr and now achieve flight times of 5 min, using about 600mAh. I will buy a new 1300 mAh battery because this bird is so much fun, now. Ralf
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Old Today, 02:49 AM
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@Dennis: When my autogyro went down in tall grass, the HK blades stayed intact, normally. Using only the outer screw and a toothpick in the inner hole of the blade holder makes the blades swing back in case of a crash.

I don’t think that the high temperatures change the flight characteristic of the rotor so dramatically. Are your really sure that the battery is OK? Can you measure the voltage of each individual cell under load? Maybe your 11*8 prop needs too much current. I flew my Jupiter Kwirl autogyro in large circles the other day, needing max throttle to stay airborne. The first circles were OK but then the bird descended slowly from circle to circle as the battery voltage decreased and I had to land it much too early. Inspection showed the battery having one weak cell. Ralf
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