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Old Jun 14, 2012, 09:39 PM
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United States, GA, Dacula
Joined Apr 2012
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Problem with glide lock mechanism on SK Ornithopters

I've had my Lazy Hawk ornithopter out twice now and noticed I could never get it to glide properly. Every time I throttled down, it would always go into "pigeon" mode (wings high) and essentially fall rapidly out of the sky. It never would go into the normal glide mode where the wings are out flat to the horizon.

Now I'm probably telling everyone something they may already know but I thought I'd share my fix in case others come across the same issue. When I started investigating why this was happening, I discovered that the glide lock pawls were not operating properly. The glide lock pawl is the ivory colored piece of plastic located forward of the motor. See picture. There's one on each side of the fuselage. These pawls are supposed to pivot freely about their mounting screw with little or no resistance. In the interest of brevity, I'll forgo explaining how they work and why they have to pivot freely. If anyone is interested, I can answer in a subsequent post.

What I found with regards to the pawls were two issues. One, the mounting screw is a simple course thread screw that is threaded into the G10 fuselage. Apparently, my bird was shipped with these screws tightened such that the pawls would not rotate. This is really a poor design choice as a shoulder screw would work much better and prevent clamping the pawl down.

The other issue was an assembly tolerance issue. The pawl rides in the gap between the drive gear and the fuselage with very little clearance. The width of the gap on my bird was just small enough that the drive gear would contact the pawl and rub; thereby preventing the pawl from freely rotating.

My fix for this problem involved replacing the original mounting screws with small stainless shoulder screws. I can't recall the specifications for the screw except to say that the thread was close enough to the thread size of the original screw that threading it into the G10 material was easy. I also had to drill out the hole in the pawl with a 1/8" drill bit. Also, used blue loctite to secure the screw to the fuselage. Someone like McMaster Carr would have the appropriate shoulder screws for sure. In lieu of a shoulder screw, I'd suggest removing the original screw, applying loctite and reinstalling WITH NO CLAMPING FORCE.

In addition, I had to remove 0.005" to 0.010" of material from the thickness of the pawl to prevent rubbing on the drive gear. After reassembly, both pawls now function as intended.

As Sean Kinkade's assembly and operations manual is a bit lacking in clarity and detail, hopefully this will help any other poor soul out there who is experiencing the same issue.
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Old Jun 15, 2012, 02:13 AM
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KOROBELNIK's Avatar
PARIS
Joined Oct 2002
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The mechanical aspect is only one part of the problem

Spring for ratchet.wmv (0 min 8 sec)


http://homepage2.nifty.com/smark/GLDABE.htm
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Old Jun 15, 2012, 05:13 AM
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I agree with you completely KOROBELNIK. I see you have a GLDABE installed on your bird (I assume that's your bird). I recently ran across GLDABE myself when researching this issue. I think it's an ingenious idea and I am very interested in obtaining one. I found where I could order one at http://ovirc.free.fr/GLDAB_English.php for 86 Euro. Do you know if this is the only place I can order one? Any chance there's someone in the U.S. who sells them?
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Old Jun 15, 2012, 06:49 AM
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glide lock pawls are hit and miss but do work if the bird is weighted properly another opton is a programable esc with a hard brake regards Brian
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Old Jun 15, 2012, 07:08 AM
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PARIS
Joined Oct 2002
818 Posts
bwayneholt,
Sorry ,before the Gldab was also sold by Nathan Chronister on Ornithopter Zone but it ended its stock Gldab. I think now we must wait till Yovio sell the Gldab, he is making in Hong Kong : Rolleyes:.
http://www.rcgroups.com/forums/showp...4&postcount=38
note: Gldab Originals, had SMD (surface mounted device) and programmable for all types of motor and esc
Best regards
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Old Jun 15, 2012, 12:57 PM
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Glide Controller, will be available next week
Ornithopters Glide Controller (3 min 3 sec)
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Old Jun 15, 2012, 01:02 PM
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Sign me up Yovio!

Wayne
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Old Jun 16, 2012, 12:09 AM
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looks great how much
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Old Jun 16, 2012, 01:17 AM
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Price for the Glide controller + 30A ESC will be SGD 85, its about USD 68.

I will only sell it as bundle cause we tried with other esc the brake functionality is not so good. If people want to buy only the Glide controller it will be SGD 65, but I will not guarantee the result will be as precise as the bundle one.

Another thing that need to be consider is sensor mounting, I don't have other bird except protoseni's bird so I can;t provide the mounting. I will post all the photo of the sensor and measurement when I'm ready to sell it. I will also post the photo of sensor mounting on Protoseni bird, it should be simple.

Please note, the above price is without shipment, the cheapest shipment to US is USPS priority mail SGD 10 (6-8 working days)

I will keep you guys updated sometimes next week. Right now we're doing flight test on the new bird. Stay tuned....
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Old Jun 16, 2012, 04:09 AM
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Joined Oct 2002
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Immediate blocking of the wings is not a good thing It's like a rearing horse. the aircraft loses too much speed . He went into a spin, just like on your video:
Ornithopter sensor Lock (2 min 24 sec)

The opening of the wing in 2 times is, for me , the best solution.
Good luck !
Video of the Proto Gldab : Juni 2007
Ornithopter Gldab Glide Modul (4 min 28 sec)
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Old Jun 16, 2012, 06:12 AM
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Korobelnik, I'm not really sure I understand what you mean. Anyway, the video that you put over there was taken sometime back, at that time we don;t have proper sensor mounting, we just tied up the sensor using tape and some cable ties. At some point the sensor was move because of vibration and improper mounting.

Anyway, we'll post the result, and if we're not confident of the result we won't sell it
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Old Jun 16, 2012, 07:05 AM
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Hi Korobelnik, i guess i understand what you mean with 2 openings of the wing.

Thank you for the input, i'll made the changes and see how it perform. Thank you.
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Old Jun 16, 2012, 07:44 AM
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I'll take the sensor and esc.. just sell me the bird to go with it as well
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Old Jun 16, 2012, 06:16 PM
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How much will your birds cost when it is ready?
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Old Jun 16, 2012, 11:41 PM
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Singapore, Singapore
Joined Mar 2012
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Looking at Bird Seller

Quote:
Originally Posted by G-LO View Post
How much will your birds cost when it is ready?
Hi G-Lo, Are you asking Yovi or Protoseni??
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