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Limits & Mixing Strategies.

#1
Hi Team,

Full marks to everybody @ FT for providing inspiration & a fantastic service.

Despite being an old bugger, I'm a newbie to the sport.
I'm learning a lot by trial and error. For example after my first dozen or so prangs I started limiting the travel of my control surfaces, adding differential travel to ailerons, playing with different rates of expo, and now I'm starting to try switchable mixes of most of these things.
The thing is, even though I have been guessing values, these have made a huge difference to my ability to keep my planes in the air, and I think a segment on limits & mixing could benefit a heap of your viewers.

You probably don't need to go as far as how to program specific radios - there's plenty of guides online for that. However some discussion on what sort of limits should be set for various styles of aircraft, for beginners, intermediate, & experienced pilots, for each of elevators, ailerons and rudder (percentages or even mm of surface edge travel) would be great.
Suggestions on amount of differential travel would also be good, and maybe even things like setting up some elevator mix with use of flaps etc. You could put short clips showing the flying effect of these things in between the theory advice.

Now we've got programmable radios, it would be good for many of us to learn how to make the most of them.

Keep up the good work.
 

xuzme720

Dedicated foam bender
Mentor
#2
+1 on this. There are so few resources that have theory and practice on these types of setups. It would be a great addition to the FT lineup!
 
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#3
When companies are starting to design a particular product, its marketing is starting and often all companies solve the target market problems. They use both tangible and intangible product for solving the target market problem.
 

Craftydan

Hostage Taker of Quads
Moderator
Mentor
#4
Lex,

They don't go into numbers, but they do cover the settings in:


As for what numbers to pick, I'm afraid that's hard earned experience, and trial-and-error -- there's a reason it's put on a switch. The builder picks a value they thinks is safe, knowing the type of model and surfaces they've built on, and hopes it doesn't crash on maiden. Then they program in something they think might be better to a switch (to fix too twitchy or too anemic), and when it's stable in the air, they flip the switch and feel how it flies. Better, it's kept, worse, it's changed. Wit practice, it''l dial in over a few flights.

two words of advice:

- Fix one problem at a time (if you can) - Change too much at once and it can confuse what helped/hurt. YMMV, but I find this helps my sanity

- GET RID OF IT. I keep getting bit by OK-but-not-great mixes/DR/Expos on planes I forgot about. When I was flying plane "A" regularly I remembered what the mix was and which position I liked. I switch to plane B, get it set up how I like -- with switches in different positions. After a few weeks on B, I change back to A, and wonder why it isn't flying as nice as I remembered. When you've got a mix/DR/Expo set you like, make it permanent and get it off the switch!
 

Craftydan

Hostage Taker of Quads
Moderator
Mentor
#5
When companies are starting to design a particular product, its marketing is starting and often all companies solve the target market problems. They use both tangible and intangible product for solving the target market problem.
Cikker,

Seems like you're making a point here, but I don't get it how this applies to dialing in dual rates, expos, and mixing. Care to elaborate?
 

xuzme720

Dedicated foam bender
Mentor
#6
I was agreeing with the more elusive of the mixes, like differential, crow or reflex, for a comprehensive episode on what changes they make on flight characteristics. Some of us might know already, but I thought it would be helpful to newer pilots...
 

Craftydan

Hostage Taker of Quads
Moderator
Mentor
#7
I was agreeing with the more elusive of the mixes, like differential, crow or reflex, for a comprehensive episode on what changes they make on flight characteristics. Some of us might know already, but I thought it would be helpful to newer pilots...
Fair point. Sorta a what-do-I-get-for-my-effort episode, for deciding the trouble vs. value of 2, 3 and 4 servo wings, and how to make the most of it in a programmable radio.

That's different than "how do you know what to set rates/expos to" -- if they've got an easy (< 30 min) answer to that, I'd *LOVE* to hear it -- but a practical mix episode (going beyond throttle>elevator mix), would be nice.
 

xuzme720

Dedicated foam bender
Mentor
#8
Fair point. Sorta a what-do-I-get-for-my-effort episode, for deciding the trouble vs. value of 2, 3 and 4 servo wings, and how to make the most of it in a programmable radio.

That's different than "how do you know what to set rates/expos to" -- if they've got an easy (< 30 min) answer to that, I'd *LOVE* to hear it -- but a practical mix episode (going beyond throttle>elevator mix), would be nice.
Exactly!
 

Lex_Dysia

Junior Member
#9
Craftydan,

Thanks for pointing out the Expos & Dual Rates vid. I had missed that one. This does touch on the topic pretty well, but doesn't go far on the actual values.

I also take your point that a lot of trial & error goes into getting limits & mixing right. Just the same I'd welcome some starting points. For example I'm planning to build one of the versa wings. I've never flown a wing before and it would be useful for suggestions on what sort of limits would be a good place to start for a beginner and for an intermediate pilot.

Maybe I'm asking for too much but I would have thought a table with a few values as guidelines (limits of various control surfaces) for different aircraft styles and different levels of pilot experience was achievable.
 

RoyBro

Senior Member
Mentor
#10
One thing that might be helpful would be a cross referenced glossary. A way of translating between terms and where to set them up on a controller. For example the term "throws". I believe that in OpenTX these are set in the Limits screen. I'm not sure if they are called the same on other transmitters.
I realize that it would be nearly impossible to cover the setup for every transmitter, but if they did one all the way through it would create a template for us to duplicate on another transmitter. It would be a collaborative effort.

I think my focus changed mid post, but I think you know where I'm going with this. Hopefully.
 

xuzme720

Dedicated foam bender
Mentor
#11
Craftydan,

Thanks for pointing out the Expos & Dual Rates vid. I had missed that one. This does touch on the topic pretty well, but doesn't go far on the actual values.

I also take your point that a lot of trial & error goes into getting limits & mixing right. Just the same I'd welcome some starting points. For example I'm planning to build one of the versa wings. I've never flown a wing before and it would be useful for suggestions on what sort of limits would be a good place to start for a beginner and for an intermediate pilot.

Maybe I'm asking for too much but I would have thought a table with a few values as guidelines (limits of various control surfaces) for different aircraft styles and different levels of pilot experience was achievable.
Most of why you almost never see set values is everyone has their own range of comfort. A good place to start is usually 50% for dual and maybe 30% for expo. I ended up around 40 or 45% expo on my Versa but it's also my first wing. I will say launching was my issue, not flying it. I kept throwing too hard and spinning it. Once I learned to go full throttle and swing it in a smooth release straight ahead, all was gravy. Wings don't like too tight a turn so take it up high and test the envelope first. Better to find out high rather than meet the ground before planned.
Here's a couple to show you what to expect..or what not to do...
This one shows a smooth launch...dark video because I had the white-balance set to daylight and the overcast was too dark for it. It's also very windy in this one...