Hi All
Somewhat of an interesting story.
I attended this years "Worlds" & "Nationals" and had an opportunity to be exposed to the Contra Drive produced and sold by Brenner Sharp. My primary observation was the Contra drive produced a very constant speed schedule but beyond that I needed to fly the drive to really evaluate it's no torque/no "P' factor attributes.
After the Nationals I was offered the opportunity to purchase Marcello Columbo's [CA Models] personal De Ja Vu that placed 5th in Prelims and 9th in Semi's at a very good price. This particular aircraft had no servos [weight] in the tail, was powered by Q80 [heavy], had made weight & correct C/G and was a perfect test bed to evaluate a Contra Drive. Long story short I purchased the aircraft and ordered a Contra Drive, two sets of props, and three gear sets in order to set up and evaluate the drive.
I now have 15 flights on this combination and am zeroing in on a final setup and trim package. The final weight is 11lbs even. This particular aircraft has the new composite wings that CA is now producing and they are over 3oz heavier than my current De Ja Vu foam wings that were painted top and film on bottom. Evidently these are an early version as Chip has assured me the newer ones are much lighter. [I hope so!] There has been a huge learning process in getting to this point and I really want to thank Brenner Sharp and everyone contributing to this thread for there help in educating me in this process.
So far all I can say is "Holly S___ Batman!" [Some may recall I used this phrase recently in the Castle Creations recall thread] Flying this combination has already proven to be "head & shoulders" better than any aircraft I have had the pleasure to fly. In major terms the biggest change over my current De Ja Vu is the vertical & constant speed characteristicsthat the drive produces. The second observation is the increase in rudder authority the drive produces. Another way to say this is there is a large reduction in yaw stability. I almost snapped this aircraft during the maiden takeoff as I had a stiff crosswind and was holding alot of rudder on rotation and scared myself silly right out the box! I countered these tendencies by flaring the rudder with two pieces of 1/2" triangular stock and a pair of stab SFG's. The SFG;s may eventually come off as I feel like they are causing some negative issues with spins and snaps.
Enough of the tech. stuff. Bellow are several Pic's of the final result. After the conversion I had a number of graphics made as Marcello flies JR, Hacker, his name , and Argentina Number.
Thanks again to Brenner and this thread in getting me up to speed. Feel free to ask questions or make comments & observations.
Regards
Dick