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05-12-2006, 08:44 PM | #11 |
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Jason
I had a long post, but then deleted it lol. I am not typing it out again.....my point still remains....it doesnt matter. Anyways, I dont see the need to continue this more We hijacked Claudes thread enough. I will make one last point...if I had a 4096 bit resolution Tx/Rx....it would not improve my competition results any. If it did I would go out tomorrow and get a 14MZ....and all pilots flying JR would be getting beat by them. Well I dont have a 14...and last I saw Quique still won the US Nats with his 10x (although I did beat him on one round...with my 9Z ) |
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05-12-2006, 11:20 PM | #12 |
RCC Supreme Contributor
I am: Claude P.
Join Date: Sep 2002
Location: Great Western
Radio of choice:
Futaba 7C and 9C, Prism 7x # of RCs: 20+
Feedback: 8 / 100%
Posts: 2,092
Total Props: 1
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OK now you have me really confused! But I did find the above posts interesting as my 9C Futaba manual does have a few blurbs about EPA and resolution. (I paid no attention to it as I have always setup for 100%)
For what it is worth: I set my EPA's at 100% and adjust mechanical linkages to give me the high rate deflection recommended by the airplane manufacturer. I then program dual rates accordingly. And finally adjust expo to give me the "feel" I want. As I get used to the airframe if I want more throw then I just increase the EPA's. For trim, I fly and use the trim levers to attain straight level flight. Then I land and adjust linkages to return the trim levers to center. Now back to my question. After I have mechanically setup the plane as laid out above, I usually end up with no need for trim or sub trim functions of the radio. So I am still at a loss of the need for them and particularly what the difference is between a "trim" and a "sub trim" setting. If it helps answer my question at all, I now have a Futaba 9C radio and also my long in the tooth trusty Hitec Prism7X. Both have trim and sub trim functions that I do not use. I don't know if I do not use them because I do not need to or if it is because I just don't understand what they are for. I am seeking clarity on the later to figure myself out.
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05-12-2006, 11:46 PM | #13 | |
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Quote:
I agree... working with TX resolution isn't the point... it is the servo resolution (and I CAN tell the difference!!!), and FAR MORE IMPORTANT, servo power. Heck, just set up your plane like you want to and push on the surface... then do it my way and do the same... tell me you can't tell a difference. I've seen the worn linkages, worn servo gears, etc... from poor setups... not for me. I don't know what types of planes you fly, maybe it soesn;t matter on yours, but I can tell that on a 35% aerobatic ship (Extra and Panzl namely), it really really really does matter. But I'm not going ot argue until I'm blue in the face... do it your way. |
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05-13-2006, 12:00 AM | #14 |
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Claude... the reason for subtrim is that the splines on all servos are not oriented the same direction... with the subtrim at 0 one servo arm will be pointed in a little different direction that another.
Take a plane with 2 elevator servos, one for each half. Set both of your subtrims to 0, and you'll see the servo arms aren't exactly at the same angle (unless you got really lucky). Set your plane up so that the elevators are matched at neutral... trimmed for level flight. Match the throws at both ends with a throw-meter or by taping sticks to the elevators and seeing if they are together at full throw. Now look at the ATVs you had to set... they will be different from one side to the other. More important... move the elevator stick slowly... you'll see that those 2 sticks you taped on won't track together through the whole range... they'll be off at your low rate setting. Now move the stick fast... you'll see that one elevator will get to full throw first. All these are side effects of not having your servo arms at exactly the same angle and not having exactly the same ATVs on both. Sub trim fixes this problem. The same is true with aileron and it makes a huge difference if you want your plane to come out of rolls on the same heading. Now, if you are just a sport flyer and your ways are good enough for you, that's great. Don't use the function. It's better than using subtrim instead of mechanical adjustment. If you are an IMAC or pattern flier these little things are very important... a plane that can't track straight through a loop means that you have to correct for the plane's problem when flying... to correct you have to see something wrong. If you see something wrong, so do the judges... deduction. This all makes an even bigger difference when setting plane up with high mechanical advantage... i.e. high ATVs. Anyway, that's why it's there... take it or leave it... up to you. |
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05-13-2006, 12:43 AM | #15 |
RCC Supreme Contributor
I am: Claude P.
Join Date: Sep 2002
Location: Great Western
Radio of choice:
Futaba 7C and 9C, Prism 7x # of RCs: 20+
Feedback: 8 / 100%
Posts: 2,092
Total Props: 1
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Ah! I see. Because the splines of one servo may be off a little from another, the subtrim is used to adjust the "zero" position of the servo so the arm attached to it is exactly 90 degrees.
OK I got that one now. So what's the trim setting for?
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05-13-2006, 07:35 AM | #16 |
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I am: Ted L
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Trim setting.
This function allows you to control how much movement the servo arm travels for one click of the transmitter trim lever. If the number is set at 10 lets say, then the servo arm will move more than if its set to 2. I usually set mne for about 4 and I find that is good for sport flying.
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05-13-2006, 08:17 AM | #17 | |
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Quote:
Start with the default setting, then you can go to a finer adjustment later once your plane is trimmed. I often find that the default setting is not fine enough to get a good trim on a model. |
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05-13-2006, 08:23 AM | #18 | |
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Quote:
Anyways...off to do the thing that really improves your flying....flying |
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05-13-2006, 09:02 AM | #19 |
RCC Senior Contributor
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You answered all your own questions on your last post:
1) You weren't listening. I didn't say the limfac for resolution was the TX, I said it was the servo.. a servo has nowhere near 1028 steps... at 100% at best is has 800 steps if senstivive to 1 ms, but most are only sensititve to about 3ms, so you get 266 steps total... 133 steps in each direction. Take 30% of that (IMAC rates on a 3D ship) and you get 40 servo steps each direction for IMAC flying. If I use 140% and do the math again, I get 56 servo steps in each direction... a marked improvement. 2) You fly pattern. You don't have your plane set up to fly 3D AND pattern, so you won't notice... you are using all 133 steps each direction (for 100%) on your pattern rates. If you set up an IMAC plane with control surfaces that are 3x the size of yours for 3D, then dial the ATV down to 30% for IMAC, you will notice. 100% is fine for you, and after thinking about it, 100% on Futaba is actually 107% on JR (different conventions). 3) I said that servo power is more important... for your pattern plane it is not as important, especially if still using the top digis... your surfaces are very small and throws are very small compared to an IMAC/3D ship. Plus you are limited to 11ish pounds. Flutter is a very real and dangerous adversary in in 3D aircraft and must be treated with the utmost respect. 4) You are obviously old and resistant to new ideas (OK.... I was totally kidding there... just trying to lighten it up a little ). I'm not going to compare credentials because I normally don't like discussing my life in a public forum so as not to seem like an arse, but we can talk off-line if you want. 5) The reason I bring up the proper radio setup for IAMC planes is that surfaces are getting bigger these days and guy are gravitating toward aerobatic models (extras, edges, etc...) far more than are toward pattern ships, and often without the knowledge it takes to set one up safely. Using large ATVs will only save them trouble and heartache one day. Anyway, have fun. Give your new radio a CTRL+ALT+DEL for me |
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