Mechanics of Flight: RC Model Turning Issues

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    Flight Mechanics
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Discussion Overview

The discussion centers around the mechanics of flight related to an RC model, specifically addressing issues encountered during turns that result in unintended climbing. Participants explore various factors that may contribute to this behavior, including control setup, model stability, and environmental influences.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant describes experiencing unintended climbing during turns with their RC model, questioning whether this behavior is normal or indicative of a problem.
  • Another participant suggests that aileron throw symmetry could lead to upward pitch during turns and recommends adjusting the aileron settings to achieve differential throw.
  • Concerns are raised about the model's center of gravity (COG) and its impact on pitch stability, with suggestions to check the COG position and elevator trim.
  • Some participants propose that environmental factors, such as wind, could be affecting the model's flight path, suggesting that the model should fly straight and level once airborne.
  • There is a discussion about the potential for over-controlling the model and the importance of making small control movements to avoid excessive climbing.
  • One participant notes the challenges of learning orientation while flying, especially when the model is approaching the pilot, and offers tips for improving spatial awareness.
  • Suggestions are made regarding the use of a buddy box system for training, which allows an instructor to take control if necessary.

Areas of Agreement / Disagreement

Participants express a range of views on the causes of the climbing issue, with no consensus reached. Some agree that environmental factors and control sensitivity may play a role, while others emphasize the importance of checking the model's setup and trim.

Contextual Notes

Limitations include the potential for missing assumptions about the model's setup, the influence of external conditions like wind, and the unresolved nature of the model's stability following previous damage.

  • #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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