Which set up would make cause the nose to want to pitch up A or B?.... I am having a hard time setting the ailerons on a plane that has them running the whole length of the wing

Well, are you talking about level trim on both sides? Meaning, are both sides set up with the same "trim"?

Why not make them center and neutral, as though they were a straight extension of the trailing edge? Then you can dial in whatever trim you need.

The elevator is going to move the nose, not the ailerons. If one aileron is off more than the other, well, you will get a slight roll tendency, not a nose up or down attitude.

CGr.

B will 'raise' the wing

A will 'lower' the wing

B will give you more lift, but the nose will drop,
A will kill your lift but your nose will raise up

a will cause the nose to pitch up. To set the ailorons properly you will need to centre the trims un screw the servo horn then have the two ends of the servo horns parallel to the wings then you adjust the length of the wires so you get both ailarons in the centre. Hope this helps

Ailerons are not the surfaces to affect pitch. The elevator is the surface that is supposed to affect pitch.

Do you have a symmetrical airfoil on the wing? or a flatbottom? Trimming the ailerons together in the same direction gives either a flap effect or a spoiler effect and whether or not those cause a pitch and how much depends on a number of things. Flap deflection sometimes causes a nose up pitch and sometimes a nose down pitch.

What is the model? and what do you actually wish to accomplish?

Ok thats what i was looking for...i have a H9 Tango that im having trouble trimming the ailerons.....I have neglected this airplane for a while, and flew her again for the first time in a few months... and the ailerons were orientedtated like A and it scared the **** out of me..... i thought maybe i was tail heavy but i doubt it now

Actually what JimmyJames213 said is not correct!

Aileron deflection affects different planes differently.

It largely depends upon the design of the plane.

I have several planes where dropping the ailerons raises the nose, and several where doing the same drops the nose.

There are other factors involved, just as Da Rock said.

The real answer is quite a bit more complex than stated in most comment above. It depends greatly on how the rest of the plane is set up. For an extreme example, look at the tail less designs that exist. The ailerons are set up as elevons and provide both roll and pitch couplings. If the CL is ahead of the CG, example A will pitch the nose up. I have had flaps on some planes that, when lowered, caused a pitch down attitude while such action generally causes a pitch up attitude requiring elevator correction to land with flaps.

For all the beginners...................

It's not a given which way a plane will pitch when flaps (or ailerons being trimmed in the same direction) or spoilers are deflected, deflected either way.

For example, many models have been designed to turn in pitch EXTREMELY fast. They were designed to turn inside very fast and to turn outsides just as fast. With those airplanes when A happened the airplane nose pitched even faster DOWN, and when B happened the nose pitched even faster UP. Why? Because the wing was increasing lift in the direction of the turn, either way and that lift helped the elevator pitch the plane.

There are models that pitch nose down when their flaps are deflected. There are others that pitch nose up when their flaps are deflected. It depends on the airfoil, the balance of the particular plane, and the location and size of the tail. And the airflow aft of the wing. And maybe one or two other things.

There is more to it than a sound bite.

Ok ill add some weight up from to be on the safe side and try to neutralize ailerons as best as i can... I just want the Tango to fly straight and be easy to trim, and most importantly enjoy it

Maybe it's just me and I'm missing something but unless both ailerons are moving up and/or down at the same time, you shouldn't have any nose up pitch issue. If you move the stick left, the left aileron should go up and the right should go down and you turn left. Generally the plane will pitch down some. The reverse is true if you move the stick right.

So, what's going on to cause you to think that the ailerons are giving you pitch problems?

Yeah it's just you!

He is talking about using the ailerons as Spoilerons and Flaperons which is not the same thing as what you mentioned.

Although I hate to say it but this sounds more like an airplane that is simply
being flown with the CG to far aft in the first place. If thats the case reflexing the ailerons either direction is not going to help.

John

OK, I have glanced over down through post #14. First your depictions do NOT provide any true information.

While one can find many variations as most model airplane depict the longitudinal axis as a point to measure incidence. In the real world that is not true. The chord line of the horizontal stabilizer is the line from which all aerodynamic incidence angles apply.
Example: A depicted longitudinal axis shows 2° downthrust, 2° positive wing incidence and a 1° negative incidence for the stabilizer. Aerodynamically the machine has 1° downthrust, 3° positive wing and zero for the stab.

Now you want to adjust your ailerons for certain wing incidence changes. OK, so what kind of wing do you have?

Most flat bottom wings have a rounded leading Edge. Since chord line is between the farthest forward point and the trailing edge, then a flat bottom wing already has some positive incidence relative to a flat stab. parallel to the bottom of the wing.
Any droop of the ailerons provides more positive incidence, more lift for a given airspeed, and probably a bit more touchy on the controls, especially elevator. Roll those ailerons up a few degrees and the machine now generally flies smoother. I cut all full span ailerons off some 2-4" from the outboard tips and glue those tips back to the main wings with a slight twist-up. T.O. and landings are much nicer and most of the dreaded "tip stall" is eliminated but never totally eliminated.

Symmetrical wings must fly at some positive angle-of-attack (AOA) normally not perceptual to the eye, depending on wing area, weight, and airspeed. A slight roll down of the full span ailerons will make the model less touchy, but inverted flight will require considerable nose-up (down elevator) pressure and the model will be seen as such. That is why most aerobatic pilots use neutral control surface settings and use an aft CG which applies the down force to load the wing to some AOA to maintain adequate lift, regardless of whether upright or inverted or on an up-line or down-line. (AOA is the angle between a chord-line and the oncoming airflow. AOA has nothing to do with INCIDENCE angles)
Roll up the ailerons on a sym. wing and it flies with the nose up dragging itseld to adequate positive AOA along with a draggy fuse. and stab. Pressure a slight bit of down elevator and it litterally wants to fall out of the sky.

I have assisted a number of RCers with a squirrely scale model on TO/Landings/ and even in-flight maneuvers by showing them how to roll up the ailerons several degrees, 1/16" or more, and therefore tame the tiger. It's simply "washout" which all machines like.

Hopefully the above explanation/s will provide adequate information for you to adjust your ailerons to what you wish. The only definite is that there is no definite. However the less differential incidence between stab and wing chordlines, the easier the machine is to fly. That will all change when you start flying Free Flight. All the statements are for subsonic convergent airflow which pretty much covers our models. If you are getting into trans sonic and supersonic divergent airflow, please write a book! [X(]

Good Luck.

I think John Buckner might be right about the CG being too far back.. Im just trying to get my Tango to fly level, and not want to climb and messed around with the incedince of the ailerons to see if helped. Upon doing some reading about the H9 Tango, i found out that these birds tend to be tail heavy when fitted out with the reccomended 2 stroke engines (ST 51 in my case), and better suited for four strokes.... My wing is a fat fully symmetrical high wing Im .....going to have to read what you posted a couple more times to fully understand Thank you for your explanation Horace

Where is your CG? They say "CG (center of gravity):4 to 5 in. back from leading edge at the wing root."

Well for a very proficient flier with a strong power plant, and wanting 3D stuff, that can work. OTOH for a sport flier with a less than a barn-burning engine, it is a crash waiting to happen.

Your wing has a slight taper. Your mean aerodynamic chord (MAC) is "close" to the mid point of the wing panels in SPAN. Not exactly but that suffices close enough for toy airplanes with such a wing.

If you go to that point and measure back 25 to 30% of that chord, and balance at that point your airplane will not be tail heavy.

Now are your tail servos at the rear of the model? If so, take those servos, place them in the fuselage and use pushrods, stiff and braced ones. Then you are moving 3 oz. of weight forward to close to the CG. That is about a 3 to one advantage or the same as adding 9 oz. to the nose, except you remain 9 oz. lighter and get the same effect, CG wise.

Since I don't know the taper and using their figures for span and wing aera:

48.5" span with 747 sq. " aera = chord of 15.4" (for the perfect rectangle) however on a straight taper that should be close to the center of the panels span wise.

25% of 15.4 = 3.85 30% of 15.4 = 4.62

Any balance point between 3& 3/4" and 4& a half " will give you a nice flying airplane.

After you get proficient with the machine, then you can do some experiments and move the CG back in small increments, along with playing with aileron adjustments. Soon you will be having it stand on its tail, and all that stuff. Enjoy!

What Hossfly is describing is an increditably quick and easy method to balance the vast majority of our model airplanes. Its so simple, its so quick and it works so good that its totally ignored in this computer fed society of helpless people. You don,t need a computer, you don,t need the plans, you don,t need to call some supplier and you don,t need count on some heresay about where to balance some model. What you do need to do is decide for yourself where you want to balance the airplane and thats the easy part.

Its called midspan averaging. Is it super accurate: No its not and it certainly does not have to be.

OK first for the midspan averaging part (piece of cake) Pick a point that is half way out between the wingtip and the fuselage. At this point measure the distance (a school ruler does just fine here) from the front edge of the wing and rear edge of the wing. Thats it, that is the Average chord (regardless of the wings leading and/or trailing edge tapers). The engineer types like to call this the Mean Aerodynamic Chord, MAC.


Now for the part were we the pilot/builder have to make a decision, what a concept And for that we don,t need a computer all we need is just a few old fashioned guide lines that never change whether or not its a gas/glow/electric or diesel airplane.

A few old fashioned guide lines expressed as a percentage back from the leading edge of that average chord we figured out above:

The vast majority of our trainers, sport airplanes and warbirds fly best at: 25% Mac and this is a perfect and safe starting place.

For fellows wanting to do the prop hanging stuff then 30 to 34% is appropriate but keep in mind its not for beginners and frequently lots of expo is used. Also the airplanes don,t fly very well in higher speed flight.

For leading edge tapered flying wings around 20% is a safe figure.

For a straght chord flying wing around 12 to 15% is the ticket to cool flights.

For controlline airplanes around 15% is a good starting place.


OK now we have made a decision and lets call it 25%, We just take that average chord we figured out with the tape measure or ruler and divide by four, That gives us the 25% place back from the leading edge half way out there between the fuse and wingtip. The last step is to just project that point inward to the fuselage (you can almost do that just by eyeballing along spar lines etc.) and this is the actual spot you want the airplane to balance level (not nose down for mother and country) when supported there on each side of the fuselage.

Took me forever to write this and it takes only a two or three minutes to actually do anywhere without this crutch called the computer.

Now following "A few old fashioned guidelines" will keep you out of trouble and will be agine "A good starting point" to experiment on your own and thats what this hobby/sport/passion is all about.

MJ Yes your airplane is being flown with the CG too far aft for you. The reflexing of the ailerons up or down does have effects that can improve various segments of flight but usually at a cost of some other end of the flight envelope.

Hoss sorry for repeating your post in kind more or less but just hoping to help get the point across.

John

not sure where the cg is on the model i threw the manual away and didnt bother CGing it, since i had the correct size 2 stroke motor, the servos in the stock locations and battery pack as far forward as possible... I will add a couple of ounces if i choose to fly it this weekend.

Horrace and John thank you for taking the time to explain how to balance a model[sm=thumbs_up.gif][sm=thumbup.gif]

Thanks John. I can always use some help! Thanks much.