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Tandem Rotor Helis Vertol Chinook > KA-22 Vintokryl VTOL
 
 
heli_madken
Senior Heliman
Location: Liverpool, England

Hi All, Although not strictly a tandem I thought you might like to see my latest project, a scale model of a 1959 Russian VTOL aircraft the Kamov KA-22 Vintokryl -



I have just had my first sustained flight albeit very sensitive on Elevator but its easily fixed -

http://uk.youtube.com/watch?v=A6oRSwBZXlA

It uses a TH2 VTOL mixer which some of you may be familiar with

I have done a complete description of the build over on Scale helicopters -

http://www.runryder.com/helicopter/t377267p1/
10-01-2007 05:07 PM
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Popcorn
Senior Heliman
Location: Switzerland

Thats a very interesting and imposing project! Respect respect!
10-04-2007 09:44 PM
 
 
tungym
Heliman
Location: Underground

I have done a fixed pitch V22 prototype 6 months ago. Icannot solve the pitch instability problem especially in windy outdoor condition. I was thinking about doing exactly your same project using collective pitch with flybar (heli head) to improve pitch stability. After viewing your video, I can still see the seesaw like pitch instability.

In addition, using heavier blades may help the cyclic stability due to gyro effect.

Here is my video.
http://www.youtube.com/watch?v=-8OM1kMtybc
http://www.youtube.com/watch?v=vduXzKXHk_o
10-14-2007 04:39 AM
 
 
heli_madken
Senior Heliman
Location: Liverpool, England

Hi,

I saw your video some time back very impressive project. I think you are right collective pitch is more stable due to the speed at which the servo's can react in pitch adjustments compared to altering the speed of motors. You can see that in how stable my KA-22 is in aileron movement

In error I had far too much gain on the elevator channel programmed into the TH2 controller I was only moving the right stick a couple of millimeters resulting in the harsh fore and aft movement in the video, I cut down on the amount of gain I had on the elevator channel and fitted a gyro, providing gyro's on all three channels. I had a brief flight last weekend which showed a huge improvement only for the troublesome left motor to give up on me, thankfully with no damage to the airframe, so I am grounded for now.

The problem I think you will have with going the helicopter CP route is transition, nobody seems to have had a great deal of success with a helicopter setup going to forward flight as the characteristics of CP helicopter blades do not suit them to being propellors. I saw one thread that showed using MS Composit 3 blade head units with propellor blades fitted to give a combination of CP in hover and normal propellor in forward flight, seemed like a good idea but didnt see the outcome

There is a good forum for VTOL's with some great guys over on RCGroups - http://www.rcgroups.com/vtols-360/ you might get some help there with the V22
10-14-2007 09:16 AM
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tungym
Heliman
Location: Underground

heli_madken

Indeed, thrust is a very imnportant component in stability. Once the rotor is tilted, the hovering thrust is shared to forward vector. I did some elevator to throttle mixing, that makes FF better. Still, it cannot overcome outdoor windy condition that makes the prototype tips over in hovering. Mine you I follow previous flier with 1024 propeller, with thrust too mean for a hovering in windy condition.

Therefore , I am looking for a E-sky king heli with rotor diameter of 550-600mm (close to 24 inchs) , which comes close to my planned scale body length of 30- 36 inches. In addition, dirty cheap for a set here($35 USD).

How do you feel using the TH-2 mixer, in terms of resolution or phase adjustment? I got 2 Omni Veetail as a preliminary CCPM mixer for testing and the lag is a bit disappointing. One can actually se the servo lag much behind the stick input.

2 Mikado V-bar would be a dream, though.
10-14-2007 10:14 AM
 
 
heli_madken
Senior Heliman
Location: Liverpool, England

If you are going the CP route (it doesnt work for vector control using motors) then I would strongly recommend the TH2 VTOL controller, it does all the DCP mixing for you and will also control your aeroplane mode ailerons, you can switch over from heli-mode to aeroplane mode using a TX switch it is a great piece of kit, there is certainly no lag.

I dont think you have that much choice actually as, to my knowledge, none of the other tandem controllers can cope with the side by side rotor layout of the V22.

Good idea to use the E-Sky components, what will your all up body weight be and what motors do you plan on using?
10-14-2007 11:13 AM
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Tandem Rotor Helis Vertol Chinook > KA-22 Vintokryl VTOL
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