Multiflyer,
thanks for the wishes, I had a nice Christmas, and you?

Now back to the discussion...

I have to thank you for your last example, I didn't think about that situation: you're right, in this case the spiraling slip stream doesn't produce any yaw, so let's eliminate it from our thinking. I understand your point and I agree with you that in this case R thrust would hurt, and in fact with such a design no right thrust would be needed, otherwise you can get bad yawing while inverted, as you correctly pointed out. Ok. To support this, the symmetrical depron biplane I've flown (I cited it in the previous posts) didn't have R thrust built. Ok, it will experience some yaw due to P-factor (again, I agree with you), but this can't be corrected with right thrust so - no right thrust. To summarize, we should not use right thrust to correct P-factor!


Now, regarding right thrust in patterns and my 4 deg... I don't think I am an exception with respect to the general airplane setup. I see right thrust built into all pattern planes I've seen and heard of. For example, let's look at the Focus II pattern airplane. The great Don Szczur, which has been 2003 FAI USA Champion with that plane, started in the past a thread about its building. From that thread, it is stated that the airplane kit comes with 3 deg of right thrust (and 1 of down):

"The good news is that the angles are all there for you. If you slide the pre-assembled piece into the slots it will give you the correct side and down thrust . Take care to put it in the right way up. The plane is supplied with 3 degrees side and 1 degree down."

Ok. Guess what Don did with respect to right thrust? It added a bit more! If you want more infos, here Don is also suggesting to modify engine mount in order to give more right thrust:

http://www.rcuniverse.com/forum/m_14...Cthrust/tm.htm

That said, I'm still convinced that right thrust should be reduced.. . in fact I started this thread because I was thinking that with fuse mods the slipstream effect could be reduced -> and so right thrust. Nevertheless, it is needed if we want to draw straight uplines. We could certainly reduce it in order to avoid bad yaw in inverted and during corners, but then the uplines... where do they go??? Ok, ideally we could correct them with rudder, but if the champions put right thrust... I think it is better to have hands off uplines and then correct during corners.

Finally, the promised link, a VERY VERY GOOD reading by George Hicks, an aero engineer of Gulf Stream, that also has a forum here on RCU (unfortunately it seems he is not present anymore on the forum [] - too bad!!!!!!!!!!!)

http://www.horizonhobby.com/Explore/...ArticleID=1101

Good reading!!! After that, I have another interestig how-to written by him...