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Here is picture of my Rabe rudder setup.
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Charles Carter
Hi Charles,
I do not think we have met and I am getting in to this discussion a bit late. I can recommend to pay serious attention to what Brett has to offer.
This about your movable rudder. If you already have experience with the Rabe Rudder and know how to trim for what you want from your model, then disregard the following.
Now, with regard to the photos you showed of your Rabe Rudder. It appears that the elevators are at neutral in that photo. It could be just the camera angle, but the rudder offset with that neutral elevator position appears to be large. I think for initial trimming, you might want to use no more right rudder offset at neutral elevator than you would use if you had a fixed rudder. Then, if more right rudder seems to be needed for your outside maneuvers, go for it. But with a Rabe rudder and when it is properly trimmed, my experience is that for neutral elevator, even less right rudder is needed than if it were fixed, then, you can adjust for the desired line tension in the outside maneuvers, you adjust to have more right rudder with down elevator. I know Al will recommend to also trim to have more neutral rudder for the inside maneuvers. That will become a function of how well your model responds to the movable rudder. My experience as well as some others that have used the movable rudder even trim to use little rudder movement for the inside maneuvers to even giving a bit more right rudder. Rabe will probably tell you to ignore this. But, it becomes how the model responds in the maneuvers, particularly in the transition from outside to inside loops. The problem you might have is that with the position of the horns you have on the elevator/rudder linkage, you are fairly limited in what adjustments you can make to your rudder movement relative to the elevators. That linkage arrangement works for Al. I know it has not worked so well for me and some others that have seriously worked with this. (There are alternatives for that pushrod linkage.)
One of the problems for some who have tried the Rabe rudder is that they use excessive rudder movements from up and down elevator with unsatisfying results. Then they give up feeling the system is not helping.
Now, I will suggest that what I said may not apply to your model at all. I have seen Igor Burger use a lot of rudder offset on his electric Max Bee. But one factor is that his rudder is comparatively small and the rudder area is fairly well centered around the thrust line.
Yes, I have been lectured that many National and International Championships have been won
without the use of a movable rudder. My only response to that is that it works for me and will continue to use it for my Open competition models.
As I suggested at the beginning of this post, if you already have experience with these things, and know what to expect, then disregard all of the above.
Keith
Topic: My new Strega ARF to battle with in 2017 (Read 10354 times)
