Ihave a seagull ultimate 90 that Ihave been flying for a few months now, so for it flies great but with the throws i have it set to just may be a bit much, how much will aile diff help with the handling of this type plane? Icurrently have the throws set to max with no dual rate set up and all channels on 30% expo.</p>

Does it yaw out of the turns excessively? If so can you overcome it with rudder easly? most likely the answers are 1. no and 2. yes, so I would say don't add it as it will make any inverted manuevers worse and with a plane like this, you just need to concentrate on using the rudder properly.

On this type of airplane you will most likely not have an issue with adverse yaw. The need for differential comes from the wing/wings with the aileron deflecting down producing more lift then the lift lost by the wing/wings with the aileron deflecting up. This imbalance causes the airplane to climb slightly whenever aileron is applied. First test fly the airplane to see if you have an issue, try some vertical rolls both going up and coming down. If the airplane does not roll perfectly axial, then you need to add some differential. Make sure all ailerons are traveling exactly the same up and down before any adjustments.

Its actually been flying ok the way i first set it up but im the type thaqt like to mess with things, but actually reading the manual, the set up is saying to for low rates at 7/8 up and 1/2 down and high rates at 1" up 7/8 down, but the current set up is equal amounts both up and down. would these changes make that much of a difference?

Yes they would. Before trying anything, do the tests I suggested. Normal flying will tend to not be affected so much but as you get into more advanced flying ike rolling manuevers on an upline you will find that without differential it is much more work. Doing multiple horizontal rolls in a strait line will be more difficult too.

For symmetrical wings, like those, the difference is negligible; especially when the plane is flying fast and at low AOA's.

For high AOA's, like during landing, severe banks or loops, the ailerons that are down may induce some yaw towards the side on which they are (adverse yaw for turns).

Remember that whatever differential you introduce, will increase adverse yaw when flying inverted, as stated above by cfircav8r, especially at high AOA's.

Rudder is your friend, always, and to coordinate turns is not a sin.

I can understand that, I have always set up my planes withthe same amount of throw in both directions and used rudder if needed to hlep in turns but just resently desided to set it up per the manual, im just curious is how the plane with react with this set up? will the turns be some what the same? As stated earlyer Inorm set rates to max but im wanting to try to set this one up per the manual, witch says to set the alierons to move higher on the upside and less on the down side.

Try it, if you dont like it set it back. No harm in trying it. You may find it works well, or you may find the manufacturer suggests it to make it more docile and easer to handle for the low intermediate flyer. Speeds suggestions are a great way to see what the differences are, try them with and without differental and see how it works.

That particular model design, will work best at wing/stab all set zero zero and ALL weight possible eliminated

the reason why is that at lower speeds they get draggy and then th aileron responses are different-beause the wings are operating at a high angle of attack-
at maneuvering speed- very low angles of attack - all is fine.

<p class="MsoNormal" style="MARGIN: 0in 0in 10pt"><font size="3"><font face="Calibri">Hate to hijack this thread with a newbie question, but I am having some problems with a Phoenix Sea Bee plane that someone at the field mentioned that aileron differential might help. When I apply a little aileron to turn, the plane tends to continue to bank more and more. On turns, I usually apply a little aileron and then use the elevator to maintain altitude. With this plane I have to reverse the aileron in the middle of the turn to avoid the continuous banking. <span style="mso-spacerun: yes"> </span>None of the previous planes I have flown have done that. Note that both servos for the ailerons are on the same channel.<span style="mso-spacerun: yes">  Thanks.
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Differential should have no effect on your problem. This is a mid wing straight (no dihedral) aircraft so it does not have a self righting tendency. As your bank increases the wing on the outer portion of the turn will be producing more lift and it will try to roll into the turn. You will notice this same tendency on all aircraft just at different bank angles. It should not be excessive but is noticeable. What you need to check though is that the controls center properly after deflection, and that the plane balanced laterally.

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You are absolutely right. I checked it, and the plane is not balanced laterally. It is leaning to port and now I remember it was bad only turning left. So, this is the problem. It's hard to move the fuel tank and the battery moved to the right has not made any difference. Can I place weights at the wind tips? What is the best way to balance the plane laterally? Thaks a lot for your help.</p>

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It is best to add weight to the tip as it will minimize the amount needed. I am sure there is a good way, but I have always just used trial and error with stick on weights. After you determine how much you need you can then affix them permanently. On solid tips I just drilled a hole and epoxied them in the hole filled it and patched it. Just make sure it is solidly affixed to the wood frame.

http://www.rcuniverse.com/magazine/a...?article_id=84