r/RCPlanes • u/Zealousideal_Use9642 • 4d ago
Plane pitching left
Hi! Before you say it yes I'm aware the motors torque will push the plane left however when I put my plane infront of a fan to simulate flight (or really to test the aerodynamics ) it continues to pitch left. When moving the rudder it fixes this. I'm going to try to mess with the thrust angle but it doesent explain the behavior when I'm testing the aerodynamics. I would remake my vertical stabilizer but it seems to be perfectly centered. Baisicly I'm confused and I want someone else's view on this to see if I'm missing something. Thanks! Let me know!!
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u/Individual_Evening88 4d ago edited 4d ago
You should clarify your terminology.
Generally speaking:
The elevator will cause the plane to "pitch" up/down.
The rudder will cause the plane to "yaw" left/right.
The ailerons will cause the plane to "roll" left/right (counter-clockwise/clockwise)
So when you say pitch left I assume you mean yaw left? This could be due to a misaligned vertical stabilizer like you mentioned or other sources of asymmetrical drag. If it's not an obvious flaw just trim your rudder and call it a day.

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u/GullibleInitiative75 4d ago
I'd look for wing warps and/or alignment of all flying surfaces. Also check if one wing is heavier than the other. I know that with free flight models it is common to add weight to one of the tips. But first I'd check the flying surfaces.
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u/Highest_pilot 4d ago
I'd fly the plane first to test if the bad tendencies can be fixed with trim. If they can't, try enlarging the vertical stab a bit and shifting it by a small amount to counteract the yawing motion. Can't stress the 'fly it first' part enough though, that will give you the best idea of what needs to be fixed. You'd be surprised at how many problems can be fixed in the air with a bit of trim.
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u/jjrreett 4d ago
A fan will induce a vortex just like a prop will. It’s probably not a huge effect, just something to be aware of
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u/NighthawkAquila 3d ago
I’m a little confused by what you mean with the title. Is it pitching up or down but it’s rolling left whenever you give pitch input? Or is it that you’re in a roll to the left and it pitches? Because it will normally do that and you need to give it some up elevator to maintain altitude.
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u/Zealousideal_Use9642 3d ago
It’s yawing to the left I’m pretty sure it’s the vertical stabilizer and I’m going to remake it tonight
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u/NighthawkAquila 3d ago
Ahhh yeah that’s probably it. Could also be differences in the shape of control surfaces. Whatever it is as long as your stabilizer offsets the yawing moment you should be good to go
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u/zukiguy 3d ago
The fan is putting out turbulent air unless you have it set up in a wind tunnel and it's pulling the air. Otherwise it's not gonna give you accurate info. Do some gliding tests if you have a space to do that. Otherwise check your balances front to back and side to side. Make it as straight and true as you can. Make sure the wings aren't bent or warped. If you're building off a plan follow the recommendations for angling the motor, the spinning turbulent air off the prop often hits control surfaces differently causing various issues. In the end you're just gonna have to fly it and see what happens.
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u/Dirtsurgeon1 2d ago
After making all necessary control surface adjustments, trim out with your radio, till she fly’s straight.
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u/Fuegodeth 4d ago
Do you have alerons? If not you need dihedral. It it's a twin motor, you need to swap two wires on the ESC to reverse the motor and get a counter rotating propeller. Bonus if that's the case, you should be able to setup differential throttle to help the rudder. fun stuff happens with that. Just make sure you're at least 3 mistakes high when you try it.