Scratch built autogyro with electric prerotator by Axbri

Rating: 4.65      23 ratings
Posted: June 20, 2013  |  4,575 views
INFLUENCE 56%

An autogyro is a combination of an airplane and a helicopter. It has a rotor generating lift like a helicopter, but the rotor is not powered in flight. The vehicle is driven forward to remain in the air, this is done by a normal propeller, just like an airplane. The vehicle is controlled the same way as an airplane, but it is a totally different experience to fly.

This is a presentation of my home built autogyro. This design has evolved from a few different prototypes. I built it four years ago, and it still flies gait today.

 

The takeoff can be very tricky with an RC autogyro. The difficult part is getting the rotor to spin fast enough, especially when there is no wind. Therefore I have made an electric start mechanism for the main rotor. It is a friction drive system with a brushed speed 280 motor that is engaged when the rotor is tilted fully backwards.

I have programmed a microprocessor the measures the signals the the rotor servos, it senses how the rotor is tilted and starts the motor when the rotor is tilted fully backwards. The microprocessor can be seen in the image below.

To control my autogyro I can tilt the rotor forward and backward, as well as left and right. The is a rudder on the tail to help with turning, but there is no elevator. I used the following setup:

  • Axi 2212/26 (Gold Line)
  • 10x4.7 propeller cut down to 225mm diameter
  • JETI Model 19A ESC
  • Old Hitec 5CH, 35Mhz radio system
  • JR NES-537 servos for tilting the main rotor
  • HTX 900 servo for the rudder
  • 4 Cell, 13.2V, 1200mAh, A123 LiFePO4 battery
  • Brushed 6V Speed 280 motor for the rotor start mechanism

Other data:

  • Rotor diameter: 980 millimeters
  • Length: 690 millimeters
  • Weight: 870 grams
  • Flight time: 5 to 8 minutes

The most critical part of an autogyro is the rotor head. The rotor blades are mounted to the rotor head using hinges that are angled in a way that makes the blades decrease their angle of attack when they are bent upwards by their own lifting force. This reduces the difference in lifting force of the blades going backward opposite to the direction of flight and the blades that go forward against the direction of flight. If the blades where mounted solidly to the hub, the rotor would need to be tilted a lot to compensate for that.

The fuselage is built of 10mm thick blue foam, reinforced with fiberglas and carbon fibre strings soaked in epoxy. Since the have been some people asking for plans of my autogyro, I have made a document with detailed high resolution pictures with annotations.

The pdf is available for download on my website:

http://axelsdiy.brinkeby.se/airplanes/autogyro/autogyro.html

Comments

mattplaneflyer June 23, 2013
Awesome! great job on the build.
Log In to reply
slav June 23, 2013
awesome couldn't stop grinning right through the video
Log In to reply
earthsciteach June 23, 2013
Nevermind - I see how the pre-rotator works, now. Nice work!
Log In to reply
earthsciteach June 23, 2013
Great build! Thank you for sharing. Does the pre-rotator disengage in flight?
Log In to reply
Axbri June 23, 2013
Thanks. In normal flight, it is not necessary to give full elevator by tilting the rotor backwards. But if I do that, the prerotator is engaged and the motor starts, even in the air. So to answer your question: no, it is not.
Log In to reply
stonekap June 23, 2013
I love the sound I t makes on the flyby! Great article!
Log In to reply
Axbri June 23, 2013
Yes, I agree. I think that the sound it makes is definitely one of the best things with this aircraft.
Log In to reply
tiiams August 25, 2013
Hey chad, we have plane and quads all over the site but one article on gyros ?board with planes I am now working on my gryo skills I suck. but the g2 from hk with improvements is taking one heck of a beating from but after repairs flys again.I love this article.
Log In to reply
Buk June 23, 2013
Very nice build, thanks for sharing.

-Buk
Log In to reply
hansdude June 23, 2013
Out of curiosity, what micro did you use?
Log In to reply
Axbri June 23, 2013
The Microcontroller. It is a PIC12F683. I have programmed it using mikroC. It controls the motor using a IPS031 Power switch and the built in hardware PWM module in the PIC.
Log In to reply
cyc June 24, 2013
awesome
Log In to reply
tramsgar June 24, 2013
Impressive!
I wonder what's wrong with a simple switch that'd engage the prerotor?
Log In to reply
Axbri June 25, 2013
In this case, the power to the prerotator motor is slowly increased from none to full power in about 5 seconds. This prevents the friction drive system from slipping. This solution if also more customizable. I can easily adjust both the ramp-up speed and the maximum power.
Log In to reply
tramsgar June 25, 2013
Of course, I see.
Log In to reply
Zpack June 26, 2013
This is SO COOL! I love the sound it makes!
Log In to reply
ChengShiJiaZu July 2, 2013
这时旋翼机啊!做飞机是否需要点知识呢?我想,但是资金不够哦。其声呜呜然!Do you Know?
Log In to reply
ChengShiJiaZu July 2, 2013
In this case(在这个例子中), the power to the prerotator motor is slowly increased from none to full power in about 5 seconds.(预旋器在5秒之内从静止到最大速) This prevents the friction drive system from slipping(这个可以防止摩擦驱动打滑). This solution if also more customizable(不太懂). I can easily adjust both the ramp-up speed and the maximum power(速度好调). - See more at: http://www.flitetest.com/articles/scratch-built-autogyro-with-electric-prerotator#sthash.6ZsOZ1sB.dpuf(访问更多:t: http://www.flitetest.com/articles/scratch-built-autogyro-with-electric-prerotator#sthash.6ZsOZ1sB.dpuf)。
在中国学习英语不好,考试根本没什么,有哪位高手会中文的教我英文,我的QQ1040628736,要问我的电话号码,随便回答一个!!
Log In to reply
baronbernie June 23, 2013
Love the design, it looks so simple.
Log In to reply
ChengShiJiaZu July 2, 2013
I agree with you.I love it,too.
Log In to reply
abelmagwitch July 22, 2013
This Comment Has Been Removed
abelmagwitch July 22, 2013
This Comment Has Been Removed
abelmagwitch July 22, 2013
This Comment Has Been Removed
fredira January 30, 2014
I like the configuration of it being a pusher
Log In to reply
Yogenh March 29, 2014
I have never tried one but this one make me want to try one
Log In to reply

Log In to leave comments