hey !

im also flying the contra drive and as i maybe use a different setup, brenner asked me to publish here. so here my setup :

- im using a thunder power 8S lipo with 4350mAh
- hacker C-50 competition 11winder with the hacker controler
- gear ratio 10,33 x 1
- front prop 22" x 20" rounded tips
- rear prop 21" x 22" rounded tips and cutted of 1" from the 22" diameter

right now im flying the drive, wich is running very smooth and silent, in my oxai beryll08. of course i needed some test flights to find my setup and im still playing with my center of gravity and the angle of incidence.
first i had the 22" x 20" props front and rear, but this had been a lil bit too little power for strong wind conditions. instead of changing the gear ratio, brenner recommended to change the rear prop for 22" x 22", bcs mainly the rear prop gives more speed horizontal and power. so as i made the first flights with this new prop setup i just can confirm that this is true. now i have exactly the power i need for all conditions. i also must to say that we, here in germany, fly more slow (specialy me ;-) im flying slowmotion), so the setup is not made for full speed. of course i could change for another ratio and maybe fly a 22"x22" in front too, but is not my style.
my fuel consumption is now between 3000 and 3500mAh max. before, with single prop, was always about 4000 and more! with the 22" x 20" rear prop was 2800 up to 3200mAh. so far i dont have any temp. problems even not with outside temp. of 37°C!
the flight characteristics of my beryll changed so much with the contra drive that i can not believe. its a new airplane! everything is more easy now to controll, i have so much less work, the rudder is much sensible and effective so that the rolls gets amasing, like the turns as well. what realy surprised me is that the angle of attack of the fuselage during rolls is now nearly 0 !
to controll the constant speed is very easy now, specialy bcs i can adjust the brake very sensitively. of course the effect of the brake is much more than with single prop before. about all im totaly happy with this change for the contra drive and just can recommend this for everybody! the support and service from brenner is amasing and professionel.
bye, bye,

dominik