Mechanics of Flight: RC Model Turning Issues

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    Flight Mechanics
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When flying the Bixler 2 RC model, the user experiences unintended climbing during turns, potentially due to aileron control issues and the model's center of gravity (CG). The model's ailerons have equal throw in both directions, which can cause adverse yaw and pitch changes, leading to climbing instead of level turns. Suggestions include adjusting aileron differential, trimming the elevator, and ensuring the CG is correctly positioned to enhance stability. The user also notes that external factors like wind may affect flight behavior, complicating control and learning. Overall, achieving proper trim and understanding control responses are crucial for stable flight.
  • #31
Borek said:
I have a feeling with a GoPro (additional weight and air resistance) it got more stable. Sure, it requires more power during flight, but it is not as sensitive to wind and steers as without the additional load.
That might have moved the center of mass forward a bit, did you recheck it?

Video from the local hill site, mostly Radians which I mentioned before. All I had was a basic phone, so not a great video, but enough to get an idea that these are popular. Some of the guys were doing touch and goes off the carpet.

 
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  • #32
rcgldr said:
That might have moved the center of mass forward a bit, did you recheck it?

Yes, I moved the battery to the back to keep the center of mass where it should be according to the manual, plus - as I do every time - I checked if it glides correctly before flying. Sure, I can be off by several millimeters, but not by much.

I think I moved the center of mass up though - but there is not much I can do about it.

Quite crowded place on your video, such flying requires precision that I can only dream about at the moment.
 
  • #33
Borek said:
I think I moved the center of mass up though - but there is not much I can do about it.
Adding weight will speed up the model a bit and make it less sensitive to minor gusts.

Borek said:
Quite crowded place on your video, such flying requires precision that I can only dream about at the moment.
Since they are foamies, occasional collisions aren't going to do any harm, so they can flight in tight packs if the motors are off so the props don't do any damage. They were mostly using the updraft on the hill to stay up, and they landed rather than turn on motors to avoid doing any damage. For those that launched using motors they launched away from the pack, then motored off and glided back into the pack.
 
  • #34
A short update - things are getting better, but I am still far from feeling confident. Actually I have a problem doing any of the tests we talked about earlier, as they require a stable flight to start with - and that's not something I see often. No idea if it is still a matter of gusts (last weeks were windy here, so it is quite possible) or something else, but the flight is shaky all the time despite my attempts at tweaking the trimming and whatnot.

Warszawa_z_powietrza.jpg


(the other file is a recorder flight path in text/xml format that can be opened with Google Earth - either change the extension to .kmz or unzip the file and use the .kml, works both ways).
 

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