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setting up expo on a warbird ?

Old 07-01-2013, 09:52 AM
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RCFlyerDan
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Default RE: setting up expo on a warbird ?

That is actually GREAT that you have been flying old school (late 70's and 80's, and I learned in the 70's with no expo, no computer radio!!) of no use of expo!! IF you are running dual rates on your flight controls, go to travel adjustment, and increase your end points by 10%, provided you don't have a mechanical end limit. Then, only use 10% of positive expo on low rates and 15% expo on high rates. I didn't read all of the settings, but I am old school on WarBirds, and less throw is better. Too many guys try to set up a Warbird as an IMAC plane, and that is totally wrong.
Old 07-01-2013, 02:30 PM
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flycatch
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Default RE: setting up expo on a warbird ?

In the September 2013 issue of "Model Airplane News" there is an article that covers' this topic and you should read it.
Old 07-01-2013, 05:39 PM
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Default RE: setting up expo on a warbird ?

I certainly agree that the geometry of the physical connections is very important. While a push-rod connected more closely to the output shaft of the servo will mean more travel on the stick for the same deflection, this is nothing like the 'soft' feel that expo gives you in the center of the stick, for movement is 'exponential' not linear. I think these subjects are apples and oranges here. Both great subjects to explore, but completely different.
Old 07-01-2013, 07:29 PM
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Default RE: setting up expo on a warbird ?


ORIGINAL: ram3500-RCU

I certainly agree that the geometry of the physical connections is very important. While a push-rod connected more closely to the output shaft of the servo will mean more travel on the stick for the same deflection, this is nothing like the 'soft' feel that expo gives you in the center of the stick, for movement is 'exponential' not linear. I think these subjects are apples and oranges here. Both great subjects to explore, but completely different.
The reason for going "in" on the servo wheel toward the shaft is to maximize torque. This is also true for being "out" at the control surface horn. While there maybe some "expo" realized here, torque is the main reason for doing this. Granted, this will not always give the desired amount of control movement, so we tend to be other positions to get what we need.
Old 07-01-2013, 08:59 PM
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Default RE: setting up expo on a warbird ?


ORIGINAL: vertical grimmace


ORIGINAL: ram3500-RCU

I certainly agree that the geometry of the physical connections is very important. While a push-rod connected more closely to the output shaft of the servo will mean more travel on the stick for the same deflection, this is nothing like the 'soft' feel that expo gives you in the center of the stick, for movement is 'exponential' not linear. I think these subjects are apples and oranges here. Both great subjects to explore, but completely different.
The reason for going ''in'' on the servo wheel toward the shaft is to maximize torque. This is also true for being ''out'' at the control surface horn. While there maybe some ''expo'' realized here, torque is the main reason for doing this. Granted, this will not always give the desired amount of control movement, so we tend to be other positions to get what we need.
The subject is expo. Expo relates to the 'feel' of the stick. It was in this context that I referred to the amount of movement on the stick, and how that correlates to the location of the push rod connection on the servo arm. Again, torque, or mechanical advantage (leverage), is not in question when discussing expo. It is an entirely different issue during setup. No less important, just a completely different subject.
Old 07-01-2013, 11:46 PM
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Default RE: setting up expo on a warbird ?

Ever played with Futaba 9Z ????

Regards
Dave Read
Old 07-02-2013, 03:16 AM
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Default RE: setting up expo on a warbird ?


ORIGINAL: flyingpiggy

Ever played with Futaba 9Z ????

Regards
Dave Read
Limited exposure. My brother is Futaba (9Z), I'm JR (12X).
Old 07-02-2013, 07:45 AM
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BobH
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Default RE: setting up expo on a warbird ?

I think you may have ment Septenber 2012? The 2013 edition isn't out yet ..
Old 07-02-2013, 08:02 AM
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Default RE: setting up expo on a warbird ?


ORIGINAL: ram3500-RCU

The subject is expo. Expo relates to the 'feel' of the stick. It was in this context that I referred to the amount of movement on the stick, and how that correlates to the location of the push rod connection on the servo arm. Again, torque, or mechanical advantage (leverage), is not in question when discussing expo. It is an entirely different issue during setup. No less important, just a completely different subject.
Actually, the OP asked about expo as a way to reduce the sensitivity of his ailerons. Either reducing travel or adding expo will solve that problem, but expo will only reduce the sensitivity around center, leaving the sensitivity at high stick movements and total travel the same. It is best to optimize the limits of travel (mechanically or with ATV/EPA) before deciding that expo is needed.

Jim
Old 07-02-2013, 08:50 AM
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Default RE: setting up expo on a warbird ?


ORIGINAL: LDM

Yes as crazy as it seems I never set up expo on any of my warbirds . After reading a magazine article recently I think I am really missing a great radio asset .
On the Spectrum 7 I know the + means less sensitivity , my question is , is there a right formula for warbirds ? Will expo be differant on one flight surface vs another ?
Thanks
Hi,

I use expo on my warbirds and find it very useful. Unfortunately, there is no particular amount of expo that will work for all planes and all control surfaces, so it's going to take some experimentation to find the amount of expo that works for you and your planes. It is very much a matter of personal taste. When you begin your experimenting, using 20% expo (-20% on Futaba radios) as a starting point will be enough to feel how the expo works, without causing any problems. I am assuming that the linkage and servo geometry is all correct.

Like Ron101 said below, on my large warbirds, I generally use dual rates, high rates for take off and landing and low rates for flying. Both the travel and expo are higher on the high rates than on the low rates. Once airborne, this helps me fly smooth on low rates, but provides more control surface throw during take off and landings when my planes are in a low energy state. Some of my large scale WWII planes have relatively small control surfaces and narrow landing gear, so it is helpful to have more control surface throw (and expo) during takeoff and landing. But, there are exceptions! For example, on my 1/4 scale bf 109 (102"; 35lbs), on high rates (for take off and landing) I have full travel but no expo on the rudder. Why? Because the bf109 has narrow landing gear and a relatively small rudder and it tends to yaw hard left on takeoff, so it is helpful to have a large amount of rudder throw without any expo to provide the quickest response possible. This helps me keep the plane straight during the takeoff roll. Once this plane is airborne, I switch to low rates, which has a small amount of rudder travel and some expo so that I can fly smooth turns using rudder, elevator and ailerons. So, as you can see, every plane is different.

Good luck and have fun with it! You may find it to be a valuable tool for you and your planes. If you would like more information, please feel free to PM me and this weekend I can look at my settings for one of my planes and give you some specific numbers that I use.

-Ed B.
Old 07-02-2013, 09:10 AM
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LDM
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Default RE: setting up expo on a warbird ?

Pete and everyone thanks . My goal is eactly like many of you stated , smoother flight ! I am 100% connected as far as the mechanical side of flying from CG to lateral CG , to every manual setting possible . I am not connected to the luxuary of what the new computer radios can do . I was not even mixing flaps with elavator until a year ago , yep old school when it came to flying , it was all me lol.
So now I am simply traying to take advantage of the fact that I have the technology withen my radio so why not play with the settings and see how I can improve my flying .
Thanks
Old 07-02-2013, 09:14 AM
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Default RE: setting up expo on a warbird ?

Whoops.. my bad. Just got my Sept 13 edition today.
Old 07-02-2013, 12:15 PM
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flycatch
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Default RE: setting up expo on a warbird ?


ORIGINAL: BobH

I think you may have ment Septenber 2012? The 2013 edition isn't out yet ..
I'm a subscriber and received my copy yesterday.
Old 07-02-2013, 12:19 PM
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predman
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Default RE: setting up expo on a warbird ?

I always put in some expo on my rudder, that way when I up the throttle the rudder doesn't move with it if I am not dead straight as I go up.
Old 07-05-2013, 04:19 PM
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Default RE: setting up expo on a warbird ?

LDM it also depends how much movement you like the sticks to move in order for the plane to respond. Me personally I like you never use Expo and that is because anything more than about 1/2 inch movement in the sticks is a sloppy feel to me. I need to have a good solid response from the plane at 1/4 inch stick movement. The only time full stick travel is ok is in a roll or loop. The feeling of moving the sticks to the half way point to get solid movement does not sit well with me.
I think you may have too much surface deflection for your stick movement. It could be you are one of those that rather the feel of moving the sticks close to half travel to get a response from the plane. Expo will help you there, but have someone by your side on test flight to flip that switch in case things get too slow.
Old 07-06-2013, 03:06 AM
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LDM
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Default RE: setting up expo on a warbird ?

91Zulu I do like the feel and immediate response but need smoother control . All the control horns are adjusted at the best place so it was time to play with the expo . I agree and will have someone with me to judge feel and help with the switches .
As crazy as this sounds its also a matter of the time of day that you fly . Early morning flight after coffee and you tend to be more quick on the sticks , later in the day more relaxed (that is for me ) , so I am conscious of every aspect when I fly.
I am anxious to get the feel for some expo and see how it goes.
Old 07-06-2013, 01:41 PM
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Default RE: setting up expo on a warbird ?

I always put in some expo on my rudder, that way when I up the throttle the rudder doesn't move with it if I am not dead straight as I go up.
Me too, but I fly on mode 1 & tended to pull the elevator stick a bit sideways which added rudder & resulted
in screwy loops.

My radio (Futaba 12 FG) has 'point' mixing so you can set the sticks to have no movement around centre.
My rudder now has a dead spot around centre which has improved my looping manoeuvres.
This doesn't effect rudder expo. - John.
Old 07-18-2013, 05:01 PM
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Default RE: setting up expo on a warbird ?

The first time I ran into what Dan is referring to was with a first gen Futaba 7 CAP. You could mix two elevator servo's on two channels, 2>7, but the expo nor the trim from ch2 would carry to ch7. Which was interesting since they allowed the aileron to carry from ch1 to 6 for all those mix's.
Its my understanding that Futaba fixed this oversight on a later gen of the 7C.

Back then I ended up getting a nice servo reverser from Electrodynamics to get around the prob.
Cheers.

ORIGINAL: BarracudaHockey


ORIGINAL: All Day Dan

Use 30% on the ailerons and elevators. If you use a ''Y'' connector for them you will get the same expo on each surface. If you are using different channels for each one it may be dependent on your radio. Dan.
Sorry, but computer radios put expo on the function, not the individual servo.

If there's any radios that are otherwise, please let me know which, because in my somewhat admittedly limited experience, I've yet to have seen one.

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