Hi,

Can someone explain why pattern planes do not have full span ailerons? Most of the artistic models are full spanned in order to be 3D capable. Would this have any kind of "bad influence" during pattern maneuvers?

I'm asking because most of the top pattern designs have kind of semi span ailerons. Is that related to drag issues mostly?

Rgrds,

Nick

Turbulence/ disturbed air over the stab.
ie Aileron deflection changes airflow and therefore effectiveness of the rudder and elevator.
The less coupling in a pattern plane the better, so to have the application of one control (aileron) affect another controls power is a negative. Outboard ailerons= more leverage, less airflow disturbance (that matters to us anyway).
Cam

Cameron thanks! Reasonable answer, I wonder though if 10-15 degrees of max aileron throw used on pattern planes is enough to cause such turbulance effects taking into consideration the relativelly lower speeds that modern pattern fly?

I don't know, just wonder...

Nick

The older pattern planes had full span ailerons. I'm flying a Widebody and it has them except for about 1 1/2 inches from the fuselage. The aileron area is huge. The Epsilon is the same. I've heard from someone that the Widebody seems somewhat smoother for pattern flying without ailerons and elevators running out to the tips. Some of the older designs had flutter problems with ailerons running to the tips and builders would shorten them to cure this.

Tip vortices would depend on a few things besides just ailerons going to the tips. Shape of the wing tip would be a major factor. Wing shape matters a lot.

is that why old pattern planes have their elevator not on the same level as the wings?

HI Snap

From what I've gathered over the years it used to be thought that putting the stab higher meant that the tail-plane would be more efficient if it wasn't in the wake of the wing. However at that time the designers hadn't considered the down-wash that comes from the wings. Therefore having the stab on the same line means that the tail is actually operating in clean air, to put it simply.

Having the stab higher tends to lead to some control coupling in many designs, which is why the later designs are more 'pure' to fly.

As for full span vs inset ailerons, it can be seen from the above argument that it is a matter of taste as opposed to pure aerodynamics.

Many people have shortened the ailerons in order to try and stop tip stalling in certain designs, but seeing as some maneuver's require a clean snap, then a controlable tip stall is a good thing in aerobatics. As with full size, models are designed to fulfill a specific function and their design reflects this. I have found that having some aileron in the wash of the prop has lead to better control at landing speeds, but then I have also found that barn doors for ailerons has the same effect!!

Steve

I'm reading the question to also include the inboard (next to fuse)part of the aileron, not just the tip. Concerning that part (inboard) a 3-D plane needs to feel some of the propwash to have aileron control in hover and other near-zero airspeed maneuvers. Our pattern planes don't . We're not flying that slow,Yet
Eddie

So guys you think that artistic designs with full span ailerons such as Synergy 140 3D or may be the CAModel Epsilon 120 will have degraded performance in pattern compared to a genuine pattern plane with outboard ailerons?

The long and the short of it yes.
Have a look at the early Majestics, they had split ailerons to allow the inner section to move conditionally (ie different radio modes).
I would assume that this is to obtain the best of both worlds (in the respective phases of flight).
But the later Majestics and now Synergy 3d etc have a single continuous ailerons, apparently this is to save the weight of the 2 extra servos required for split ailerons.
So the weight penalty of the servos must have been deemed to be more of a performance loss than the airflow disturbances caused by full span ailerons.
So full span ailerons will affect performance, to what degree is subjective, and depends on your level of flying I guess.

Any peice of equipment designed to a single single set of criteria (F3A plane) will outperform equipment designed to fulfill 2 sets (ie Artistic Aeros stuff). Simply there is less compromises to be made.
Cam

This is interesting and I'm not trying to be argumentive....I'm flying a Widebody now with the same aileron design as the Epsilon. I'm flying pattern with it. I don't see where this is hurting pattern flying at all. Rolls are axial. It likes to roll either with short throws or a lot, and with very good precision. It is an intuitive plane, so there is no fighting it or forcing it to do what it needs to do. I'm just not sure where I'm lacking with the setup.