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Questions about three channel versus 4 channel and dihedral versus non-dihedral

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Questions about three channel versus 4 channel and dihedral versus non-dihedral

Old 05-07-2021, 11:57 AM
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Default Questions about three channel versus 4 channel and dihedral versus non-dihedral

Hi I have been wondering for a long time why there are no dihedral wings with significant dihedral whatever that means I'm not sure what I mean by that but what seems to be by comparison significant dihedral and also ailerons along with that. I know that the angel tends to work against the other ones but they used to make planes like the train star that had significant they call it and Anna runs now I noticed there are plans like the ranger which is supplied by horizon hobbies and made by a company I think it's called emm or something like that and there's one that I saw Nate on RC sailors demonstrating that I don't know where it was from but it was a system and it had anarons and flaps and no safe technology and only slight dihedral but I guess a big part of the question that I left out so far is that I want to see some made without safe technology that have ailerons that have significantihedral and I don't see any like that. Even the ranger has very little dihedral. I see that he's your significant and certain three channel planes like the many arrows are which is actually polyhedral and the WL toys Cessna f949 but that's only three channels and I can't seem to see any with the combination of all three no save technology dihedral and Aaron's. And they're mistaken about that if so where are these airplanes for a long time I thought there was nothing without safe technology that didn't have Street just three channels I'm glad to know that there are plans like the ranger and their sister that Nate was showing but it still leaves me wondering whether I should buy I just like I've said many times before just give up on the hobby because I can't even fly a sport cub s reliably in the advanced mode, I don't want to spend $150 on an airplane that I can't fly and end up destroying it I can't afford that but three channels is a compromise does anybody get the drift of what I'm trying to get at? Can anybody enlighten me? You see I can't help but feel that there's an opinion going around that flying with the safe mode it's not really flying or cheating or something and I kind of agree with that in a way but to find a plane that I can fly without it is very difficult

Last edited by obrien135; 05-07-2021 at 12:00 PM.
Old 05-13-2021, 05:53 AM
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Wow man. Punctuation is a really valuable thing. Look into it.
I think you want to know about what dihedral does and what flying 3 channel vs 4 channel planes is like.
Dihedral does 2 things: 1. It makes a plane self-righting in the roll axis, which means it will always return to straight upright flying on its own if disturbed. 2. It creates a roll coupling with rudder, which means rudder application will also result in a roll in the same direction.
Both of these effects become stronger with more dihedral.There are other aerodynamic design choices such as wing sweep and placing the wing above the vertical center of gravity that accomplish some of that too.
For flying: A rudder only plane with dihedral is easier simply because it's simpler. Old school trainers like the Sig Kadet or Telemaster could be built with ailerons for sure, but often weren't because they were so beginner friendly without them. 4 channel planes open you up to being able to fine tune your turning characteristics, cross control to handle more wind, and roll the plane without yawing in order to do rolling aerobatic maneuvers.
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049flyer (07-20-2021)
Old 05-15-2021, 12:25 PM
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Hard to know for sure, but I think he's also asking why he can't find 4 channel planes with a lot of dihedral. The short answer is that most high-wing planes don't need much or even any dihedral to be stable, and too much dihedral on a high-wing plane with ailerons messes up turns because the dihedral worsens the adverse yaw you get by using ailerons. Many years ago Lanier made a trainer with four channels and way too much dihedral. You had to use the rudder along with the ailerons to make a decent turn, and that's a lot to ask of a beginner. I suppose with a modern radio you could mix rudder and ailerons, but back then computer radios weren't a beginner thing.
Old 07-06-2021, 06:30 AM
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Agree with all of the above. Rudder only planes usually didn't have ailerons. They weren't needed and could mess up turns. On the bad side they didn't do well on wind. Any sideways gusts might flip it over into the ground. But they were beautifully stable in calm weather if flown on low power with generous up trim to slow them down, then just steer them around the sky. Avoid flying them with to much down trim as it makes them fly fast and they get very sensitive and twitchy to rudder control. Aileron planes, with less dihedral, could handle higher speeds much better and were not at all sensitive to rudder as they had little to no dihedral. In short, planes with lots of dihedral are good in calm or low wind conditions but not good in wind. Aileron planes handle wind better but are less stable.
Old 07-13-2021, 08:49 AM
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Great information here.

Also the advent of SAFE and AS3X reduces the need for aerodynamic stability. The old four-channel stick and balsa trainers have more dihedral than the current generation of e-flite foamies.
Old 07-18-2021, 01:40 PM
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Dihedral isn't really much about aerodynamic stability though, even though I agree with the point that the electronic systems have made it possible to have maneuverable planes that are also wonderfully stable. But traditional trainer traits- dihedral wing, lots of incidence, flat bottom airfoil, etc, are more about making the plane self-righting. If you are banked 90 degrees and let go of the sticks, the trainer will side slip for a second and then roll itself back level. If the sticks are released in a shallow dive, the plane will lift its nose and return to fairly level flight on its own. Trainers did for years aerodynamically what the stability system's trainer mode does electronically. That's also why though nearly everyone who graduates from their trainer to an Ugly Stick or 4 Star (or equivalent) says the new plane is easier to fly. Trainers resist being rolled and pitched.

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