Flight B/C

[bjt4888]

Hi everyone!
While I'm waiting for our kits to arrive, I decided to try and document as much useful trimming and design advice from last year's and previous flight forums. Flight forums are always super full, so I wanted to thin down the amount of reading I would have to do. Does anyone know what years of Flight/Wright Stuff had rules closest to the designs we're seeing this year? I know the Wright Stuff rules from past years were a lot stricter, but as far as I can tell 2019 and 2020 seasons were both restricted to monoplanes, while 2021 allowed for biplanes? I feel like most trimming advice from the monoplane seasons will hold up to the 2024 season, but I also don't want to go through hundreds of pages of forum posts. Thanks in advance!

Random,

Good thought to do some early season research. The Division C 2015 and 2016 season Wright Stuff forums have lots of good detail in them. Last year’s forum advice would be most applicable to this year. 2016 had the 1.5 gram motor rule, however, that season also had rules that specified very small wing area and a 20 cm prop. Best trimming is best trimming regardless of the airplane configuration. So, although the 2015 and 2016 years had very different airplane configurations the process is still the same. The main challenge with the wide wing chord and short tail moment we had last year is that the CG sweet spot is is very narrow. Slightly too far forward and the airplane looks fine but is actually draggy and fast. Too far back and pitch stability suffers. This year’s slightly longer box will allow a small improvement in tail moment and slightly bigger CG sweet spot and better pitch stability.

Enjoy!

Brian T

[randomdogonapc]

To be honest, I just read all of them. 2010-2022. Multiple times. For whatever reason I found them very entertaining to read?... but if you have time I'd definitely recommend reading all the forums. It sounds like a lot more than it actually is and is kinda enjoyable! And it does help reinforce the information sometimes because a lot of it is repeated between each year.

[randomdogonapc]

To be honest, I just read all of them. 2010-2022. Multiple times. For whatever reason I found them very entertaining to read?... but if you have time I'd definitely recommend reading all the forums. It sounds like a lot more than it actually is and is kinda enjoyable! And it does help reinforce the information sometimes because a lot of it is repeated between each year.

I finally worked up the motivation to start reading all the forums and I go to the 2009 WS forum and it’s 98 PAGES pumptato ma’am you are insane



Well, see you guys in 3 months when emerge from my cave of ancient flight forums.

[pumptato-cat]

Haha it's fun! I just read in the car or between classes (or during classes don't tell my teachers please !!) or between homework breaks.
Hmm haven't read 2009 in a bit; I might start another reread soon. Thanks for the reminder :)

[randomdogonapc]

Back again!
In a lot of the older forums, there's a lot of reference to rolled motorsticks and booms, and how they're an easier way to change your stab angle than solid sticks. What happened to make them mostly unused last year(at least, I think they were)? I also saw one of the coaches post about how the bending of a solid stick during a flight leads to some desirable flight characteristics, which is kind of my only lead there. I'm sure there's plenty of guides on how to make them, but what advantages and disadvantages do rolled sticks have to solid ones?

[bjt4888]

Back again!
In a lot of the older forums, there's a lot of reference to rolled motorsticks and booms, and how they're an easier way to change your stab angle than solid sticks. What happened to make them mostly unused last year(at least, I think they were)? I also saw one of the coaches post about how the bending of a solid stick during a flight leads to some desirable flight characteristics, which is kind of my only lead there. I'm sure there's plenty of guides on how to make them, but what advantages and disadvantages do rolled sticks have to solid ones?

Random,

Good job discovering some interesting design ideas. SO designs don’t need rolled motor sticks and tail booms. If we need to adjust stab tilt, we slightly crack the LE and TE attach points to the tailboom and then change the angle slightly, verify no twist in the stab and reglue the joints with one drop of CA. As this setting rarely needs to be changed more than once, this simple method works fine. We use the same method to adjust tailboom offset, if necessary (crack the TB/fuselage joint partially, adjust, maybe insert a very thin shim in the joint and reglue).

Rolled motor sticks are a weight saving design element used in the very lightest airplane classes like F1D.

Brian T

[bjt4888]

Back again!
In a lot of the older forums, there's a lot of reference to rolled motorsticks and booms, and how they're an easier way to change your stab angle than solid sticks. What happened to make them mostly unused last year(at least, I think they were)? I also saw one of the coaches post about how the bending of a solid stick during a flight leads to some desirable flight characteristics, which is kind of my only lead there. I'm sure there's plenty of guides on how to make them, but what advantages and disadvantages do rolled sticks have to solid ones?

Random,

Good elements to focus on in your research are rubber winding, trimming (CG, decalage, washin and turn settings) and flaring propellers. These are the areas that can give the biggest flight time improvements.

Brian T

[randomdogonapc]

Makes sense, but with the more open design options this year, could rolled motor sticks be a viable option for a biplane? I feel like an extra wing would be hard to build under 8g with a solid motor stick, but maybe that’s just my bad construction habits talking…

[pumptato-cat]

I don't think I've ever seen a biplane beat a monoplane. Interesting idea, though!
Because of how small the planes were last year I built one to 6.6g. I think that's enough for another wing? I wouldn't say your construction habits are bad, especially if you're considering making a rolled tailboom :)

[coachchuckaahs]

Makes sense, but with the more open design options this year, could rolled motor sticks be a viable option for a biplane? I feel like an extra wing would be hard to build under 8g with a solid motor stick, but maybe that’s just my bad construction habits talking…

Rolled motor sticks give a great bending to weight ratio than solid, but are a significant increase in complexity of build. This year's motor sticks are not overly long, so should not be an issue.

However, before considering rolled sticks, consider a smaller cross section with a vertical truss. A small vertical stick (toothpick) at center, going up 1-1.5". Then run a truss wire (kevlar) from front, up to top of toothpick, and then down to the rear hook location. This will increase bending stiffness more with little gain in weight, and allow a lighter motor stick

Coach Chuck