Need suggestion on setting throws
 

The manual on my plane states for example aileron throws to be set (Low 11%) - (High 25%) Should I set all my throws on the lower settings until I dial this plane in and get some decent flight time with it? I've checked all the throws ail,elv,rud and they're all very high. The elevator is over 30%- the manual says elv high throw setting 28%. I'm wanting it to fly scale like. No loops or rolls for me. The Turnigy G60 motor has turned out to be a beast of a power plant with some wicked torque I'll have to learn to deal with. Like a Hemi in a Pinto. The floats are all done except for paint and detail. She's getting close!

RE: Need suggestion on setting throws
 

First thing, need to know what kind of plane. Warbird, Civilian scale, Sport, Aerobatic
Edwin

RE: Need suggestion on setting throws
 

Whenever I setup a new plane I always set the control surfaces for the maximum that called for in the manual. Most manuals will also give you a low rate setting as well, which I also setup. You want to go with the max amount for the first flight because it's much better to have too much control throw and not need than it is to need control throw and not have it. If you take off and find that there is too much on the high rate setting you can switch to low rates so that you have less throw.<div>
</div><div>Hope this helps</div><div>
</div><div>Ken</div>

RE: Need suggestion on setting throws
 

I've seen and gotten into trouble with recommended throw on some warbirds. I ended up with too much elevator and aileron which made the plane a handful. I also watched a warbird newbie loose a corsair the same way. The plane snapped at low altitude and smacked the ground. I will agree with Ken on sport, aerobatics, and civilian.
Edwin

RE: Need suggestion on setting throws
 

Thanks Ken, I'll set it up per your suggestion. The plane is a 71 inch J3 piper cub. Question???? What is positive and negative expotential?

RE: Need suggestion on setting throws
 

positive and negatives are dependent on the radio as to what they mean. Now most radios operate under the premise that positive expo will soften the middle of the stick throw. meaning a small stick input results in a very small surface movement. the exponential part then ramps up to the end of the stick movement makes the surface move a large amount. This is less noticeable with smaller number and more exaggerated with larger numbers. All that being said expo settings are like throws in general it is a taste thing there are good starting points but some people like more and some like less. I usually do not use expo on a plane unless I have trouble controlling the plane with good throws. I currently only have expo on my 3d aircraft and on an edf. I use typically smaller amounts than others with similar planes. Once again it is a taste thing. BTW Negative expo would do the inverse of positive and make the stick movement more pronounce at center and then deaden the ends of the stick movement. I can't recall anyone using negative expo but surely someone must use it.

RE: Need suggestion on setting throws
 

Great answer and in a way that I fully understood it. So expo could be very handy if you had fast servos and mine seem to be faster than my other planes. I like the idea of the expo and I'll experiment a little. It looks like to me it would make the planes movement much smoother. I'll be running my throws on the low settings so I may not need any expo???

"No loops and rolls for me."

Set at low rates. You might want more on the rudder if it is a tail-dragger.

I prefer exponential to high/low rates.

Expo has nothing to do with how fast your servos are. It's for when you need the occasional big throw at the extreme ends but find the center to be too sensitive to be able to fly comfortably and smoothly. I find that about 20% is a good place to start. It softens up the middle just a bit without making the ends feel sensitive.
As for your Cub throws, no way should you need 28 degrees of throw on any surface. I assume that you mean degrees instead of percent anyway. Cubs need a bit more rudder than your trainer does, but even then it's easy to get into a bind by overcontrolling the plane with too much throw. For the first flight, I'll recommend splitting the difference between low and high rates and adding 25% exponential in the right direction for your radio. Use that setting for your initial trim flight only just so you know you'll have enough throw to bring it in if your trim settings don't go far enough, then back it down to low rates and keep it there. Since you're very new to piloting in general and to Cubs in particular (which have been known to make guys with 2-3 years experience commit mild acts of blasphemy more frequently than any of us would like to admit) I'll offer a few tips.
1. Wait until you have a windless day. Cubs suck in the wind.
2. Use a couple of yardsticks or something similar to make sure the wheels on the main gear are straight. Some guys like to run a 1/2 degree of toe in, but I find that straight wheels are a bit more forgiving. Even with that, Cub main gears are not at all a forgiving design so you need to get it as straight as you can.
3. Make sure that after aligning the main gear properly your tail wheel tracks straight with the rudder also straight. If you don't, you'll fishtail that thing all the way to the scene of the crash.
4. Choose a windless day. Cubs suck in the wind.
5. Try to fly when there isn't much wind, as Cubs are very sensitive to the wind.
6. Delay flying the Cub at all until you're comfortable using the rudder. It's optional on a trainer, but mandatory on a Cub since the tail is so much smaller and the fuselage is so short compare to the wing.
7. Have a long runway. Cubs are floaters on the landing approach, and you'll likely overshoot your first few dozen landings.
8. Control your lift on landing with the throttle. It's the right way to land always, but a Cub with that giant wing will let you pull the nose up and stall it right into the ground whereas a trainer will just drop its nose.
9. Don't depend on the plane to self-correct. A Cub, if anything, will self-uncorrect. You have to be on the sticks and keep it flying in the direction you want it to.
10. Don't try to make it into an aerobat or a hot rod. Cubs are wonderfully relaxing planes once you get to know them, so let it be that for you. I can't stand to see guys stuff big power plants into them and then pull huge verticals and consecutive rolls with them. There are planes for that, but let the Cub be that slow lumbering floater that it was designed to be.
11. Don't fly it on windy days until you are very comfortable.
12. Expect a pronounced left yaw just as you advance the throttle and before the tail comes up and compensate with right rudder. Release the right rudder as the tail comes up and let the plane track straight on its own. Then give it a touch of right rudder as you rotate to take off. If this takeoff procedure doesn't give you a predictable and straight takeoff, then either you skipped step 2 or 3 or your runway is impossibly rough.

Note also: excessive exponential makes the sticks behave as "on/off/on" at the maximum throws and will make you more jerky rather than less. I see this frequently that pilots have made matters worse by programming too much exponential and they have to compensate with large stick movements. You don't need much unless the model is extremely responsive to begin with.

Thanks Jester, I thought the suggested throws listed in the manual were high like something you would see on a 3D plane. I cut the suggested throws down by 30% to start with and I'll add the suggested 20% expo. I'm running a DX7 radio. Good news is shes done with the floats finally finished and ready to fly. I don't know how others hook up they're float rudder but I didn't like the cable sleeve method and I didn't want to drill hole in the side of the fuse to hold the cable sleeve's so I went out on a limb and mounted a water proof servo in my float just ahead of the rudder then wired it with a quick plug.
http://www.rcuniverse.com/forum/atta...mentid=1906883

If you set the throws to the max in the manual as suggested then set rates to about 60% and some expo again as suggested that is a good starting point for the first flight.

I would always go with high rates on the first flight in case something is badly out of trim. If you are your own test pilot then it is a good idea to have someone standing with who knows which is the rate[s] switch[es] and which direction they go. You might be too busy to do it yourself. Ask me how I know this.

One of the club instructors will be the first to take it up and trim it out and set it up in the air. I'm not ballsy enough to attempt it. I'd like to bring this plane home from the field intact atleast a couple of times. I know I'll have to take the bull by the horns eventually.

Hi!
First of all you must set the transmitter values to 100% (or more) ! That is very important! Why? Because thats means you use as much servor gear travel as possible which means you minimize servo gear play. And servo gear play should always be recuced as much as possible to get a nice flying model.

Then ...Al trim settings should be done mechanicly first and not electronicly with the transmitter!
Why you ask?? Because that way you understand the importance of using as short servo arms as possible on especially elevator (one very important rule to remember) and how to set up the linkage so that there is no play.

Then when you have flown the plane once, land and mechanicly retrim the plane. Fly it a second time and notice how the plane feels. Land again and first then use the trim funktions in the transmitter. But be aware that reducing servo travel electronicly too much(reducing travel percentage in transmitter under 50%-75%) on especially elevator and aileron is not a good thing as it will induce servo gear play.
At home mechanicly re-trim the plane again and set all travels to 100% or more in the transmitter and fly it again!
That's the way you set up a plane!

Jaka does bring up an important point- you want your high rates to be set with as much servo travel as your mechanical linkages allow. My radio goes up to 150%, but with the standard L bend that I use I can't go quite that high without it binding. So I do as he said with the one exception that I go as high as I can without binding, then get the high rate throw set via the mechanical linkage if I can. Sometimes I do still wind up turning it down anyway, but at least I'm using as much torque and reducing slop as much as I can and still get the throws right.

To get the most of your servo and radio set the max possible trow I think the DX is good for 125 the reason is that the resolution and torque of servo are calculate at max deflection.....so to get all the torque and all the resolution you need max trow of the servo.....then set the surface mechanically to what ever max deflection it's called for in the manual (as a starting point) the set the trow in the dual rate or flight mode which I prefer.....set the expo + plus for JR/Skeptrum - for Futaba...don't be afraid to used the radio to do the mixing that is why we now have these computer transmitter.