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Author Topic: Why do low-winged models prefer to fly left?  (Read 275 times)
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Crabby
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« on: March 26, 2018, 10:19:21 AM »

It would seem to me if the above is true, and it seems to be, a good plan of action would be to add slightish wash-in, to the port wing instead of wash-out. I had a badish time with my HE-112. It wanted to dork in to the left. When I trimmed for right flight, it climbed (right) till the downwind part of the circuit, then dorked in to the left. Could this be the effect of the inverted gull wing, and not quite enough wing area to cover the thrust line? This is a model that has a good reputation and I built it well, its light, and I had high expectations. Its on the gurney with slight port wing leading edge drama. Maybe a good time to rebuild that part of the wing and (build in) wash-in?
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Why do low-winged models prefer to fly left?
Why do low-winged models prefer to fly left?
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tom arnold
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« Reply #1 on: March 26, 2018, 10:52:27 AM »

I can only speak for my own experience, which may well be not the best, but I have found putting wash-in (trailing edge down) is a recipe for never ending problems. Should a model climb to a stall, or get bumped into one by a mild gust, that wash-in causes that wing to stall before the other and the wing drops and the model dives to that side. Increasing the wash-in (the most "obvious" solution) just makes it stall quicker. This is for outdoor models only as indoor models with the dead calm air use this very successfully.

I always put washout in my models as it stops all of this tip stalling. Washout forces the tips to stall AFTER the inner wing does such that it mushes down forward without falling off on either wing. That's the theory and most of the time it works unless some other force is trying to roll the model at the same time.

If you have a straight glide with NO prop on it, you have a good base for trimming (a freewheeling prop will roll a model usually to the right). I have found if I have any roll to the left after a good glide test, then it has to be torque. The best cure for that is right side thrust. Practically all of my planes will go into a right spiral when the motor runs down due to the aforementioned freewheeling prop. I kill that with a dab of clay on the left wingtip or a drag plate on the lift wing tip. I don't like tabs on the wing tips because that screws up my, hopefully, equal washout. You can also put in a smidge of left rudder but I fear this as rudder is very strong especially with increased power. I know that this all fights the right thrust but getting the right balance is what makes sunny afternoons over tall grass fun. Great looking He-112.....I like the tissue work.Very clean.
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SBlanchard
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« Reply #2 on: March 26, 2018, 12:02:19 PM »

Just an observation: I put a straight edge on the pic you provided of the overhead view of the model. It looks like you may have a little left in your rudder. See if that is true. If not, just ignore me.

Steve
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