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Old Sep 23, 2009, 07:50 PM
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Slidell, La
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Help!
My long awaited pusher build! Time for blades!!!!

I've been working on this for quite sometime now and finally got to the point that I need some input! Not only on the machine itself but on the head also! I am wanting to give the two blade head design a go but I need to know what size blades I should build. I would like them to be a rigid foam build first, but I can build them out of bass and balsa if need be. The current weight as it sits is at 9.70oz 15 3/4in long and 10in high at the top of the dc plate. Any and all input is welcome

The prop is an apc 7x4 behind a am400xt
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Old Sep 24, 2009, 12:12 AM
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Comment #1. " nice 'gyro mate. "

Hi pilot_dragonfly,

Looking very neat there, I like your DC head connection.
Untill some one more experienced in two blade operation comes along to answer your question, have you read all the great information here, (sorry if have already) it's all I can offer.

http://www.autogyro.com/technic/tech.htm

Good luck with getting her airborne, cheers,

regards Al
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Old Sep 24, 2009, 12:28 AM
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Hello,
Looks like an interesting build. I'm curious to see if the Ball links you're using on the control links, and the head pivot point will be sufficient for load bearing(They appear to be the type that just snap together right?). I hope it works out, that's an innovative idea if it works(Otherwise it's dumb if it doesn't ). I would reccomnend trying a three blade setup for your initial tests, and getting used to the model. A two blade setup is always more responsive, and gernerally more difficult to handle until properly set up. Just my humble opinion though, I wish you the best of luck! I'm just over in DeRidder, we need to link up sometime and do a bit of flying. Again, very nice build!
Regards,
-Mike

P.S. Do you have previous Gyro experience? Heli/fixed wing? what's your background?
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Old Sep 24, 2009, 03:16 AM
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Hi,

very clean-looking gyro. I agree with Mike: save yourself a lot of frustration and build a three-blader first. 1.5" blades, 15" to 17" long. And use a horizontal stab until you've grown used to flying these things.

Have a look at the 'Micromum' thread, this may give you some ideas how to build a head for a gyro of this size.

One question: how do you prevent the gyro's head from turning around the vertical axis?

Jochen
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Old Sep 24, 2009, 03:32 AM
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Hello Jochen,
That's a good point! I didn't even think of that until you mentioned it. The head would most likely pivot clockwise/counter-clockwise as seen from above, in addition to the intended for/aft, left/right tilt. Perhaps if the control rods were stiff enough it might prevent that from happening.
I would also suggest a hang thrust test to see how far the motor should be offset to the right. Could somebody post the link for him to the offset testing videos Jochen and Rich did?
-Mike
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Old Sep 24, 2009, 07:50 AM
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I'm not sure what I'm more impressed about....how clean your build is or how clean your workshop is! Nice!

What's your weight? It looks very solid, like spruce and ply so I would be curious how much it weighs.

On the blades, you can always go with 3 blades and if works, then build a two blade assembly. If you do the two blade, I would think you'll have to go with the teetering head with that size model......
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Old Sep 24, 2009, 11:09 AM
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As for flying expierence I have over 15 years in r/c heli's and about the same in building and flying airplanes. In other words, I have a very firm grasp on piloting twichy machines The weight as it sits is right at 9.70oz. To keep the head control from twisting cw or ccw I have damered behind the ball link using medium fuel tubing. I have done some rudimentary tests by holding the gyro by the top of the shaft, powering it up and giving 3/4 throttle while working the elevons quite roughly to see if it can atleast hold up to that test! It passed with flying color's! I will be setting it up later on today for more accurate testing and video. Thanks for the compliments guys, I am very anal when it comes to my models!
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Old Sep 24, 2009, 12:52 PM
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Heres a bit of video!


Pusher gyro motor offset test (1 min 56 sec)
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Old Sep 24, 2009, 01:23 PM
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I used basswood, balsa, thin ply, foam for the vertical stab and styrene for the rest. My motor offset is from center to center a 1/4in. Would it be possible to run it without a teetering head? I have built one but I did'nt like the way that it turned out. This has to be a 2 blade setup, if not I did it all for nothing! To make my flying skills a bit more understanding, I fly the majority of my heli's using -10 on the expo. I like a very touchy machine
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Old Sep 24, 2009, 01:30 PM
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Outstanding! Looks like the offset is good to go, or at least close enough for initial test flights for sure. The dampening material behind the ball link seems to be working exactly as you intended, I couldn't see any rotation of the head in the video. That is a very clean looking design. I'd like to point out that in no way was I trying to be condescending by asking what your experience was, just wanted to guage what you might need guidance with. You hit the key buzz word with your experience, and that's "Used to flying twitchy machines" LOL . Good, you'll need that experience! I'll be watching the build for sure! Keep up the great work, and thanks for sharing your ideas.
Regards,
-Mike

p.s. PM me if you happen to be U.S. military; if so I could arrange a flight in a full scale helicopter for you since you're so close.
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Old Sep 24, 2009, 01:43 PM
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Quote:
This has to be a 2 blade setup, if not I did it all for nothing!
That's a nice teetering head. I'm just reccommending the three blade because gyro's don't fly like Heli's or fixed wing. Our backgrounds were very similar when I started flying gyro's and you're in for a different flying experience that's going to be (And I warn you) addictive. You could easily swap from a three bladed head over to the teetering head. Three blade heads are just a bit easier to manage. The difference between the two could be compared to a heli that is set up for hovering and pattern work vs. a heli set up for 3D. One other thing you might do is research the number of R/C gyro's in this forum that are flying without a horizontal stabilizer, and take the findings into account for your design. Then again your heli experience will help very much with an unstable autogyro. I'm looking forward to seeing your blade build as well, sounds like you have some innovative plans there too.
Regards,
-Mike
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Old Sep 24, 2009, 01:45 PM
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Thanks for the offer bro, but i'm not in the military. I have had over 120 flights in different heli's though! I worked offshore for quite a long time and had to fly out many times. Plus, I have a couple of good friends with a old bell heli and a cessna. I am actually disabled now from crabbing the majority of my life when I was'nt offshore. Pulling in 600-800 crab traps a day takes a mean toll on your body! So now i'm stuck at home everyday building toys! Lifes cruel ain't it! It has its ups and downs! At the momment i'm trying to decide on the material for the blades. I would like to go with rigid foam blades but balsa and bass would probably be better. I've been reading all the stories and suggestions on autogyro's for around two years now and have finally decided to go for it. I have about 3 days worth of work into this one and have built the whopper twin rotor gyro but never did get to fly it. Long story! Anyway, i'll keep posting my work and add more vid as soon as I gets some blades built.
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Old Sep 24, 2009, 02:03 PM
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Here's a link for the Aerobalsa web-site's blade finishing tips:AB's blade finishing tips
You could talk to Mike Smith about your design, and he would be more than happy to suggest the correct size blades. I have several sets of blades from AB, and the quality is outstanding. Guys have varying degrees of success with the AB blades based on the application and preperation. Some guys say they are TOO efficient, but I think that may be because their aircraft were set-up with lower performance blades and the AB blades changed the flight characteristics. In any event, it's worth checking out, could save you tons of time.
-Mike
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Old Sep 24, 2009, 04:18 PM
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Teetering head vid. Not sure if I want to use it or not, but it would be a big advantage!

teeteringhead (0 min 15 sec)
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Old Sep 24, 2009, 04:31 PM
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Hey guys, gotta another quick question. Would it matter if on the teetering head that the center balancing point be underneath the blade line or does it have to be in the center? I hav'nt found any info on this subject!
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