AXN Trimming, Dual Rates and Expo

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AXN Trimming, Dual Rates and Expo

Postby Hallmark » Tue Apr 10, 2012 7:09 am

Hey all,

I decided to start a new thread because the subject matter of this posting has been my saving grace flight-wise.

I spent most of my last flights chasing the AXN and trying to trim it in, but every time it ended in a crash of one sort or another. So I decided when I got home to investigate some different set up qualities of my radios (Futaba 10CG and Spektrum DX6i). I repaired the AXN and made sure all of the control surfaces were operating within equal throws and went online for a quick lesson in radio transmitter set up.

What I was pleased to discover was a very well explained introduction to dual rates and exponential. When you're dealing with the DX4 or DX5e these features are not available, but with the DX6i they are and thank God for that!

So I set the following percentages on the DX6i and placed the high/low rates all on one switch for ease of access so if it all went wrong I was sure control could be regained by use of one switch and not needing to flick three while trying to stay aloft.

Here are the settings I used:
Aile: Low = 70% - 20% - High = 100% - 30%
Elev: Low = 80% - 5% - High = 100% - 15%
Rud: Low = 60% - 10% - High = 100% - 20%

So I mounted my trusty #3 key chain camera (which didn't want to work after my last prang), and off I went. I really wish the camera had worked because the flights were spectacular (IMHO). Once I got some height and the wind died off I trimmed the elevator and ailerons and bingo, no forced landings - even when the wind gusted to 20-25km p/h I had complete control for each 12 minute flight. I was stoked to say the least that all my inputs were controlled, went as directed and despite some trouble getting the AXN to land (wind again) I had the best flights ever!

As such my advice to budding AXN pilots is to get a radio that will allow you to set DR and Expo, then find what you're comfortable with. (I think the Turnigy 9X will do this.) I have to say this has made my confidence jump about 60%, which means I now feel 65% confident in my flying. :lol: Seriously though if you feel frustrated by crappy flights, try this set up and let me know how you went.

I hope that any experienced pilots (including our RC Guru Bruce) will comment accordingly with any information I may have omitted in promoting this 'discovery'...

Hallmark
Last edited by Hallmark on Tue Apr 10, 2012 10:32 am, edited 1 time in total.
"I am prepared to meet my Maker. Whether my Maker is prepared for the great ordeal of meeting me is another matter." Winston Churchill
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Re: AXN Trimming, Dual Rates and Expo

Postby RCModelReviews » Tue Apr 10, 2012 7:45 am

I'm sorry to have to say that I don't use dual rates on any of my models and on a simple model like the AXN I don't even use expo.

I fly my 3D machines with huge control surfaces and +/- 50 degree throws with just one set of rates (but quite a bit of expo).

Perhaps it's because I'm old (although that's just a rumor) but I believe in keeping my model setups as simple as possible. I learned some time ago that dual rates can be a trap and that when something goes wrong, there's never enough time to change rates which will inevitably mean you've got the wrong rates set to save the model.

Most people say that my models are set up *way* to sensitive for them to fly -- but that's the way I like it. I have full control available if/when I need it but using very subtle stick movements gives me the required amount of fine control at other times.

Likewise, I don't use any mixes -- I just use my brain and thumbs.

I watch people spend hours and hours trying to come up with mixes to allow them to do perfect knife-edge flight without any rolling or pitching tendencies. Hell, if I flip a model into knife edge and it starts to pitch towards the canopy -- I push in a little down elevator. If it starts to roll in/out of knife-edge when I apply the rudder -- I just correct it with the ailerons. That's what *flying* is all about. I much prefer *flying* to programming a radio ;-)

However, I know that what spins my wheels probably doesn't spin other people's wheels so I say "whatever works for you" is the main thing. Some folk will really want to set up a million rates, flight-modes, mixes and other fancy features that their transmitters offer and good for them!

Me, I'll just be flying while they're flicking switches, and dialing knobs :-)
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Re: AXN Trimming, Dual Rates and Expo

Postby Hallmark » Tue Apr 10, 2012 10:27 am

RCModelReviews wrote:I'm sorry to have to say that I don't use dual rates on any of my models and on a simple model like the AXN I don't even use expo... Likewise, I don't use any mixes -- I just use my brain and thumbs... That's what *flying* is all about. I much prefer *flying* to programming a radio ;-)... I say "whatever works for you" is the main thing... Me, I'll just be flying while they're flicking switches, and dialing knobs :-)


Please forgive my naivety (and inexperience) Bruce, but the events of the other day were so awful that I considered throwing everything on eBay and giving up altogether. It is very disheartening when you're trying to do everything for the first time and remember what went wrong last time and why, then to try and incorporate that into a new set of flights without disaster... Makes flying more like work not play! I put this *option* up for those who might be having the same experiences as me, not as a new way to fly, but as an assistance while these skills develop.

After writing the first post I went out again and flew another 2 batteries (about 25 minutes). As it happens I must have done something right in setting these values because as I said I flew like I knew what I was doing and the only adjustments I had made to the set up (other than a heap of repair tape and glue on the AXN) was the DR and Expo. From the difference in flights I would have to say - from a beginners perspective - that this has helped me immeasurably. Now whether this was a placebo effect or not I doubt I will ever know and I'm not sure if I really want to...

My intention in posting this was to try and find a way to make newer players feel more in control, perhaps I am projecting my faults onto others who knows? But I posted the information in the hope that I could help another noob to overcome the issues I've had to deal with. When I am more experienced (say in 25+ years) I shall endeavour to fly with my brains, thumbs and no help from my transmitter - I promise! Until then I will enjoy my new found freedom with all the help I can get that makes my time enjoyable. ;)

I did flick the switch to high rates and the difference was noticeable, so much so that after a couple of circuits I switched back before the wind gusts saw me over correct and plough into the ground. I suppose I should have mentioned that it was great to have control of the AXN for the first time where I could complete proper circuits, figure eights, loops and aileron rolls (incorporating elevator as learned on the simulator). There was a group of people nearby who cheered when I did multiple loops (power on - off - on) and I even got an inverted flight for about 20 - 30 metres. Personally I reignited my passion today and as the plane was not really tweaked I have to give credit to the DR/Expo.

On that note: I will tone down the low rate for the rudder to about 60% because when I did some rudder turns I would have sworn the ailerons were hard at work. More after my next flights.

Hallmark
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Re: AXN Trimming, Dual Rates and Expo

Postby cynr100 » Tue Apr 10, 2012 12:14 pm

Hallmark wrote:Please forgive my naivety (and inexperience) Bruce, but the events of the other day were so awful that I considered throwing everything on eBay and giving up altogether.
Hallmark

Grrrrrr... :x :x :o

"There was a group of people nearby who cheered when I did multiple loops (power on - off - on) and I even got an inverted flight for about 20 - 30 metres. Personally I reignited my passion today and as the plane was not really tweaked I have to give credit to the DR/Expo."
Yay........ :D :D 8-)

I haven't given up, I have a plan......................at the moment I just have to hurry up and wait.

What ever you do and it works for you keep it up.
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Re: AXN Trimming, Dual Rates and Expo

Postby Hallmark » Tue Apr 10, 2012 2:11 pm

Thanks mate and you will be pleased to know I pulled the key chain camera apart and used some soldering skill I had no idea I possessed and clipped the power wires (as they were badly kinked and looked broken), then re soldered them to the curcuit board! 8-)

So tomorrow's weather is supposed to be great for flying and I charged all three of my batteries in the hope of some early morning flights with video...

I will post on my channel if all goes well and post here if it doesn't :?

Hallmark
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Re: AXN Trimming, Dual Rates and Expo

Postby Stroman1 » Tue Apr 10, 2012 3:21 pm

I guess I am kind of like Bruce. I have always flown without programming in any help. I am also like Bruce in that I am rumored to be old! I also built a lot of my equipment from kits so they were simple radios going back to single channel escapement and galloping ghost, 6 and 10 channel reeds etc. (kit brands were World Engines-Controlaire, Ace and others). To make matters worse, I am left handed and built my stuff that way(Futaba Mode 3 is the same as my home built stuff). Point being, use what works for you and make no apologies cause we are in this for the fun of it. I have been fortunate to find RC Model reviews as it has helped me expand my knowledge and has saved me money by changing my old radios over to FrSky 2.4 ghz and it works!! I encourage all who benefit from the knowledge that Bruce shares without cost to support his efforts by making whatever donations you can afford to further his work. I started buying and selling model engines on eBay to help support my hobby, so using my Paypal account each month to make a small donation is fairly painless. If you can't donate, again don't apologize, use some other means to support Bruce's efforts such as mentioning his sites and this board to all your modeling friends. OK, off the soapbox!! Let's go watch some great videos and get excited! Thanks for reading! Stroman1 (Pete)
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Re: AXN Trimming, Dual Rates and Expo

Postby Hallmark » Tue Apr 10, 2012 11:05 pm

Thanks for the reply and please do not take me the wrong way - I have much to thank Bruce for and had it not been for his efforts I doubt I would have had so much fun as I have. I guess the problem with written forums is context is hard to wire into your words...

Perhaps Bruce could incorporate some new fonts for us too? Happlica - for when you're pleased Sarcastica - for when you're having a go at someone's total stupidity and Bantang for when it is beer o'clock! Just a thought... :)

I know this will make my Cairns connection really happy - I'm off to the park (found one literally 2 mins walk from the house) and going to fly fly fly the morning away... See you soon with new video I hope...

Hallmark
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Re: AXN Trimming, Dual Rates and Expo

Postby Shotglass » Tue Apr 10, 2012 11:23 pm

i dont understand the point behind dual rates either and have never used them and to my knowledge neither has my friend and mentor whos been flying for some 15ish years now
all i do as a standard is add 25% expo to all inputs and im done with the input filter side of programming
but then again we both prefer tray radios which have much bigger throws on the sticks and hold them in a pinch grip which is just so so much more precise than thumbs on a hand radio that you dont even hang from a neck strap
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Re: AXN Trimming, Dual Rates and Expo

Postby cynr100 » Tue Apr 10, 2012 11:45 pm

Hallmark wrote:I know this will make my Cairns connection really happy - I'm off to the park (found one literally 2 mins walk from the house) and going to fly fly fly the morning away... See you soon with new video I hope...
Hallmark


:x :x :x .......................... :(
Not enough time in the day for all my crazy ideas, I'm not slow, I'm just pacing myself
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Re: AXN Trimming, Dual Rates and Expo

Postby pldb64 » Wed Apr 11, 2012 12:19 am

One aspect of trimming / setup i'd be interested in feedback from those that have AXNs (Prof Bruce? :-)) is what amount of throw you have on airlerons, rudder & elevator?

I found when i set mine up initially, i really had to tone down the amount of surface movement to make it sufficiently docile for this humble newbie.

I'd found the proposed setups in one of the setup up/instruction sheets (the arrow one - not the one that came with the AXN) and set mine up with approximately 12mm movements in all directions. That proved to be quite sensitive for elevator, a little sensitive for ailerons and ridiculous for rudder.

So at the moment i have my Tx limits setup to only use 80% ailerons, 50% rudder (ie full stick movement results in 50% of available servo movement).

Bruce, when you're setting up an AXN for a newbie at your field, what amount of throw do you setup for?

Anyone else want to offer what their setup is like (with corresponding experience levels).
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