heli_madken Senior Heliman Location: Liverpool, England
| Hi All, thought now that I have it flying I would share with you my latest project, its a twin rotor / twin propellor semi scale model of an obscure russian VTOL aircraft circa 1959, the Kamov KA-22 Vintokryl. The aircraft was designed as a compromise giving the advantages of a helicopter in vertical take off and landing, plus fast forward flight given by the forward thrust of the propellors. It still holds certain records to date for load and speed categories. The project was abandoned after two crashes, they just didnt have the technology to see it through.

I cant make my mind up which forum this belongs as its definately not a tandem as such but neither is it true scale so apologies if it doesnt quite belong here.
I started out by getting a set of plans off the net, I then did the design work in AutoCAD drawing it up as a 3D model -

The wings and fuselage are made from 1.5mm birch ply formers with aluminum reinforcements using the same sort of techniques you would use to make an RC Aeroplane, covering is Solarfilm -

Next I worked out cyclic controls for the helicopter heads, tail surfaces, flaps and ailerons -

I used JGF 500TH for helicopter rotors and geared JGF 450TH motors for propellors all driven by seperate Pheonix 45 ESC's. Motors are mounted in outboard nacelles made from 1.5mm carbon fibre -

The rotor heads are 450 sized (720mm Rotor Disc) and are my own design 4 blade heads to match the original, shaft size is 6mm with ECO 8 swashplates and my own design swash drivers -

A GY240 gyro controls tail and a G190 controls aileron -

Mixing for the two heads is via a Techmodelproducts TH2-VTOL controller. This applies differentail collective pitch to the heads to control roll and yaw -

The TH2 has an extensive range of settings programmed via a USB link to a PC. I am using a 10 channel RX with all channels occupied!, the heli has 13 servos in total, the flight mode switch controls 3 modes via a range of TX mixes -
Helicopter mode (hovering), only the 6 cyclic servos are active (flaps and ailerons are set in fully down position), only the two 500TH motors are driven
Hybrid mode (transition to forward flight), all servos are active, power is split between the two sets of motors, gain is reduced to helicopter cyclic servos
Aeroplane mode (forward flight) as above but power is reduced further to 500TH helicopter motors, TRex autorotation hubs are fitted to allow autogyro effect
Some of the mixes -

Wiring all this together takes some thought! -

I still have the fuselage to cover which I wont do until all testing is complete -

I am at the stage of testing now, I intially had some problems (and still have) balancing both rotors which I intend to solve using the new eMultiGov governor by Aerospire. I have been able to sustain flight now although in the video I am attaching I had the gain set too high on elevator so it looks a little uncontrolled but thats easily fixed -
First showing rotor balance problem -
http://uk.youtube.com/watch?v=Cv-fou4rxfk
Second showing soem taxi testing -
http://uk.youtube.com/watch?v=MjFM_7l24C8
And sustained flight albeit sensitive on elevator but aileron and rudder are rock solid -
http://uk.youtube.com/watch?v=A6oRSwBZXlA
Next is to sort elevator sensitivity and fix governors then more testing
More pictures in my Gallery |