AC-10 Gyrocopter

by FliteTest | August 24, 2015 | (10) Posted in Reviews

Leave it to Peter to pick up one of the wierdest RC models we've seen to date. This is the AC-10 Gyrocopter by Unique. 

Unique is the best word to describe this thing too. The 1320mm rotors have no motor basically making this a flying windmill.

Some autogyros have a pre-rotator motor to give the blades a kickstart, but this relies on wind. 

The guts feature a 4250 outrunner motor with a 60 amp ESC (4S 14.8V 3000-3300mAh Lipo battery recommended)

Peter being the only one who's actually flown one of this crazy machines, was a little more excited than the rest of us. 

Flying autogyros takes a lot more attention to the craft and the surroundings (a.k.a. situational awareness) than normal fixed wing flying.

Also, more attention to which direction is down wind. When flying downwind the thing has a mind of it's own!

The biggest challenge is keeping the blades moving at all times during flight.

Maintaining proper head speed is done through throttle and pitch management.

Too slow of a head speed will cause the gyrocopter to roll violently to the left. The inertia of the blades will carry the entire gyrocopter over and crash. 

At the end of the day, there is nothing quite like the "thwop" of the gyros blades. 

This is a blast to fly, but definately not for first time flyers. If you are looking to challenge yourself as a pilot and step out of your comfort zone, this might be just what you're looking for. 

If you are interested in gyrocopters but a little intimidated by the price, you might want to start with the simpler Durafly Auto-G2.

In either case these are something out of the ordinary. If you are looking to shake it up at your flying field, gyrocopters are the perfect way to do so. 

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COMMENTS

SGRacer on August 24, 2015
Great episode! Im not a gyro guy, but this was fun to watch and informative.
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RockNBurn on August 24, 2015
Cool. I like gyros, but only flown them on the simulators.
I challenge Peter on making a swappable gyro.
Go Go Go!
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Axbri on August 24, 2015
Autogyros are fascinating! I scratchbuilt a couple of gyros a few years ago, this is my most successful one: http://flitetest.com/articles/autogyro-with-pre-rotator
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RockNBurn on August 24, 2015
I was wondering something about gyro building. The blades are standard heli blades with a bit of positive pitch?
There is so little information about gyros.
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Axbri on August 24, 2015
I do not think standard heli blades are a good idea. On an autogyro you want blades that are more flat on to bottom side, not symmetrical like heli blades. And they should have a few degrees of negative pitch, to keep them spinning. I made my own blades out of balsa. Look here if you want to see more details: http://brinkeby.se/downloads/AutogyroPlansV1.pdf
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rick_harriss on August 24, 2015
No the blades generally have a flat bottom profile and may have some positive twist at the tips. Chopper blades are generally symmetrical.
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rick_harriss on August 24, 2015
http://www.jefflewis.net/autogyros.html
is a good paper on autogyros and their principles.

https://www.google.co.uk/search?q=model+autogyro+plans&biw=1920&bih=953&tbm=isch&tbo=u&source=univ&sa=X&sqi=2&ved=0CCAQsARqFQoTCOCKqOzVwscCFUZvFAodSqAAYg

Many many model autogyro plans
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Blesson on February 17, 2019
I would like to explain you about the difference in some Autogyros, wherein some have a negative local angle of attack (AOA), where as others have slight positive. Before proceeding anymore, please understand that we often misunderstand the real angle of attack with local angle of attack. Local angle of attack is with reference to the rotation plane, whereas the actual angle of attack is with reference to the relative wind. Though local angle of attack may be positive or negative (always positive in case of real Autogyro), relative angle of attack should always positive, or else there will be negative lift.


Usually negative local angle of attack is provided to help rotor turn initially, but it greatly restricts the rotor RPM. The advantage of having a small positive angle of attack is that it allows high RPM to rotor, but demerit is that rotor can't spin easily when exposed to wind, instead RPM needs to be induced by connecting the engine to the main rotor for some time until main rotor picks up speed.


Cadilus 5E does have an extra motor that gives an initial high speed spin to the main rotor, therefore the local angle of attack is not necessary to be negative.

Of course, a conventional rotor blade of helicopter can be used, but local AOA must be very small, compared to helicopter. That is why pilot suddenly lower the collective during an engine collapse, in order to set the rotor into auto-rotation. Also there need not be provision for pitch altering, a simple rotor head is sufficient.

If you have any doubt about Autogyro, reply below....


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rick_harriss on August 24, 2015
Juan de la Cierva, the father of the autogyro, discovered very early on the issues you had with the model. To solve this he arranged for the blades to be able to flap up and down independently in a hinge. this allowed for the leading lagging blade problem by letting the leading blade fly higher then the lagging blade. your model does not appear to do this. Worth the modification. -- ref: http://www.jefflewis.net/autogyros.html Nice Model have fun. As a passing point a full sized autogyro can and does land vertically and in a relatively low wind can hover much like a helicopter. They are however a fair bit slower than a helicopter with the advantage of much better fuel economy.
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stay-fun on August 25, 2015
I don't know about this model (yet, I've ordered it), but the auto-g(2) definitely allows for flapping. Problem is, at low headspeed the blades don't flap, because there isn't enough force on the blades by the air, due to the low headspeed. So they don't flap quite yet, and that's why the model wants to roll left.
Actually, it would be better to outfit a model like this with a clockwise prop, so the motor torque counters the tendency to roll left at low headspeed. I tried it in my early gyro-times, but it's better to just get the head up to speed :)
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rick_harriss on August 25, 2015
If you stop the video on a shot of the rotor head you can see the blades are solidly connected to the head with no apparent hinge mechanism so I deduce (and from the behavior in the air) it doesn't flap as it should. Lots of models do away with this detail to make a relatively more simple rotor head.
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stay-fun on August 25, 2015
Hmm, interesting point. I checked out the pictures in this thread and on hobbyking, and indeed there doesn't seem to be any mechanism for that (unless they are hiding a feathering shaft&dampeners). Bear in mind though, that this size is close to a 700 size helicopter. I have one of those. The forces on the blades are LARGE, and even the most rigid rotors have to give a little. And even if they wouldn't, I'm sure the blades themselves would bend a little at the bolt.
Actually, isn't the sound the blades make a demonstration that the blades do flap? I thought flapping is the origin of that sound.
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rick_harriss on August 25, 2015
Don't know about the sound. The blades are carbon so i guess there isn't a lot of bend in them anyway. It will be interesting to see what you find when you get yours. You may be modding it in the near future! Hopefully not as radically as Peter did :-)
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stay-fun on August 25, 2015
:) I'll probably start a topic on the forum when I get mine maidened.
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Yogenh on August 24, 2015
Looks like something I would like to try. Don't know how good I would do.
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Gryf on August 24, 2015
Interesting little bird! Too bad you unbuilt it there at the end...

Gryf
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Snarls on August 24, 2015
Great episode with a fascinating machine! I was on the edge of my seat with Peter and Josh's flights. Nice Periscope extra at the end when you guys sadly crashed it, but I know none of those parts will go to waste!
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stay-fun on August 24, 2015
Awesome! I just ordered one of these yesterday!

I have experience with the HK auto-g. Pretty good machine, although quite tail heavy. I made my own (swappable!) autogyro, here is a link to the forum topic: shameless plug. Includes plans and a video!

http://forum.flitetest.com/showthread.php?10396-FT-style-(swappable)-autogyro!
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stay-fun on August 24, 2015
By the way, as an (amongst others) autogyro pilot, feel free to ask me questions on the forum (or point me to a topic you made). Don't get me wrong, I'm not a "pro" autogyro pilot, but I've built one and I can fly it pretty well. I recognize a lot of quirks that Josh and Peter mention: the rolling over to the left on takeoff, and the opposite aileron input the gyro needs in a turn. You really need to work the rudder!
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aagarmon on August 24, 2015
You want vertical takeoff and landing Peter? Build a Carter autogyro. Variable pitch head, prerotator and lots of tip weight on the rotor blades. Spin up at zero pitch and store energy, hit the pitch and you have a vertical jump takeoff!
http://www.cartercopters.com
http://www.youtube.com/watch?v=CFNc1iY8wi0
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Grizz on August 25, 2015
Ruddy great video guys and great to see you both flying that model Gyrocopter. Here's a good video which could show a few more things about these fantastic flying machines, especially the part about cutting the engine in flight: https://www.youtube.com/watch?v=p8IB-5PbL9U
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flyguyrceric on August 26, 2015
My Grandfather is 78 and has been flying and building full scale light sport and ultralight aircraft both privately and commercially his entire life. He has told me over and over that due to the autorotating head, once one is comfortable with an autogyro, it is the safest aircraft to fly because, the motor can shut off and the craft can be auto rotationed in softly! Peter, As you were stating before, pushing forward stalls the blades by not allowing any degree of blade angle to be effficient and actually tries to reverse spin the head.....No front flips!
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Maingear on August 27, 2015
Video on main rotor's dissymmetry of lift, can't explain it better....
https://www.youtube.com/watch?v=5zj_JtleHlM

Cool meter is pegged of the chart with the Gyrocopter, great choice Peter!!

Justin
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James in the blind on December 2, 2015
Just bought a couple on the HK Black Friday sale...glad I watched this! I wonder if a model rocket nose cone (with the blunt end cut off) attached to each blade tip would help with the head speed...like a wind speed meter.
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penthane on September 28, 2019
I built an autogyro with 2 counter-rotating rotors on the same axle some yrs ago. Don't remember where I got the plans, don't remember what I changed. But it looks and flies like this: https://photos.app.goo.gl/6TnAu775DkVXT6HC9
Used 5mm foam and BBQ-skewers mainly. Rotors have steel bearings. Just hot-glued them in. I use a CC3D to control it, as I'm not the best of pilots :) It's powered by an Emax XA2212 1400kv with 8045prop. battery is 3s 2200KWh. TOW is about 800gr.
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