Hello could you please tell me the difference betwwen a snap roll and an aileron roll? Also the control stick intputs?

I'm new at this too. Here's how it was describe to me. You ge the aiplane close to stalling and then you get one wing only to stall first. I think you do that by kicking the rudder over. Then the aiplane stalls on one wing and flips over to that side. That is all I know about them.

I've done aileron rolls with my trainer. It goes over a bit slowly. It also helps to add a bit of down elevator as you go upside down to keep the plane level. It is pretty easy as long as you don't freak out in the middle and have some room under you.

To bad my trainer is 75 feet up in a tree now and that is where it is going to be for a long time. I'm just putting another one together tonight. I wish I had crashed it insted - at least that way I could salvage the engine etc. Oh well.......

a snap roll is just that , a snap. At pull power, give full right ailerons at the same time give full right rudder. Remember it will be quick, so do this at altitude.
An aileron roll is considerably slower, and you have to feed in a bit of down elevator when the aircraft reaches the inverted position.
Enjoy your flying , and above all , be safe
Bill

Technically, a snap roll does not use the ailerons. Its all done with elevator and rudder. Some pilots cheat the entry by using ailerons to induce the stall on the inside wing. Some planes will naturally snap without even using the rudder (e.g. CAP 232). The typically snap is done by pulliing (positive) or pushing (negative) the elevator and using the rudder in the desired direction of the snap. Calling it a roll is almost a misnomer, as its technically a spin, since it is a stalled wing maneuver. They can actually be performed pretty fast, but your plane better be built to take it. It puts a tremendous amount of stress on the wing.

Do a google search and you'll find lots of opinions.

Brad

Aileron roll - aileron input only. Maybe a little "down" elevator when it's inverted to maintain altitude.

Snap roll - aileron input, rudder input in the same direction, elevator input.

Throttle at whatever setting your plane does the maneuver the best.

Dr.1

dr 1 is correct aileron roll is just aileron with just enough elevator to maintain altitude
snap roll is all the sticks to one corner in other words full rudder with full aileron in the same direction full up elevator and i reduce throttle to idle to help relief stress on the airframe

bkdavy is correct in my opinion. A snap roll is a rudder - elevator maneuver, and shouldn't need aileron input. Some models might need a little aileron in the same direction as the rudder to induce the roll in the right direction. Due to the torque of the propeller, it's easier to snap to the left. Also, snapping too violently causes the model to loose too much forward momentum and thus when you stop the snap, the model will have to build up speed to fly again. The optimal control inputs are such that you still continue flying after stopping the snap.

-tychoc

What sets the snap roll apart from just a quick aileron roll is that the snap roll is quicker than possible just using aileron to do the roll.

How is that possible?

You must get the wing to stall. Just whacking the aileron stick won't do anything more than do an aileron roll fast. To get the extra speed, you hit the elevator first and as the wing is pitching, hitting the rudder puts the airplane into a super fast roll. Using the ailerons at the same time as you hit rudder insures the direction of the roll and helps the roll rate as well.

Generally, in competition, if the airplane doesn't demonstrate some pitching to start the maneuver, the judges are apt to penalize the maneuver since the true snap is done with a stalled wing. No pitching, and it's just a fast aileron roll.

Slow down some.
Snatch the elevator and as that stick is moving, hit the rudder and pull ailerons.

To keep your speed up, you can relax the elevator as soon as it's done "enough".

An inside snap uses UP and the Aileron/Rudder in the same direction.
An inverted snap uses DOWN and Ail/Rudder in opposite directions.

darock sounds technically correct, but I always do a snap with full aileron and full rudder. Really kicks the thing around in a hurry. I also like to do wing-stall maneuvers with full elevator, but in that case I'm usually trying to get the plane to tumble.

I would suggest trying your first snap roll at just above stall speed and go up from there. I know if I tried a snap roll a full throttle using full rates on my pattern plane, it would rip the wings right off.. In that thing a snap at anything more than 1/2 throttle is down right brutal.

Mike McConville explained how to perform a "proper" snap roll in the March 2006 issue of Model Airplane News, page 126. In the article, he describes how the common pilot snap rolls by inputting full stick deflections, and how this makes the snap too "deep", causing the model to lose too much energy. He then goes on to describe an "unloaded" snap, that is still a full snap that is legal in competition and retains much of the plane's energy.

Here is part of the article, where he explains the procedure:

"The snap is initiated with elevator only. For a positive snap, first pull hard up elevator. For a negative snap, push hard down. As soon as there a visible pitch up of the nose, move the aileron and rudder simultaneously to full delfection. The same applies to a negative snap, except there will be a visible pitch down of the nose before moving the ailerons and rudder to full delfection.
At the same instant as you start to move the ailerons and rudder, also start removing the elevator. The object is for the elevator to return to the neutral position at the same moment as the aileron and rudder reach full deflection. A very easy way to look at this is for the right stick (mode 2 pilots) to draw an imaginary checkmark (he then refers to a figure).
When done correctly, you will see a fast pitch in the direction of the snap, meaning up for positive and down for negative. Immediately, the model will begin to autorotate around the roll, yaw, and pitch axes. Because the elevator is unloaded, however, the model wont go as deep into the snap and it will stop faster, lose less energy, and remain on the original heading it was on before the snap.
.....
The ailerons control the snaps speed. As you do a snap with this technique, if the speed of the snap is too slow, increase the amount of aileron travel. If its too fast, reduce the aileron travel.
Rudder input controls how deep the model stays through the snap. If the snap is too axial (that is, if it looks like a fast roll and the nose doesnt move far -if at all- off the model's line of direction as it snaps), increase the rudder input. If, however, the snap still looks too deep, there is probbaly too much rudder throw even though you are unloading the elevator correctly. Using a computer radio makes these adjustments very easy.
Do everything as described above, and you will be 95% there. But there's one last thing: when you exit the snap, release rudder and aileron when the model is where you want it to be. With the unloading technique, the model wont really over-rotate much. At time, though, the model will wiggle a little as it stops rotationg.
Here is one last tip and you will know just as much about snaps as I do: When the model is a 1/4 turn from where the snap is supposed to stop, release the rudder. When it gets to where you want it to stop, release the aileron. This will get rid of the wiggle, and it will look great."

(Copied verbatim from the March 2006 issue of MAN. Author: Mike McConville)

Hope this helps!

EDIT: SPitfire good article.[8D]

If you want to keep your airplane, dont snap it at full speed. Build up some speed and then chop the throttle back and snap it about 1 second later. You may have a hint of throttle on during the snap but not much. Snaps are easier, and safer to practice on a 45 degree upline or downline. Keep them high, especially if you are new at it and you are flying a plane with a relatively high wingload as the snap can be difficult and if you dont know what you are doing, sometimes impossible to stop.

Now, by definition in the AMA RC Aerobatics handbook heres the basic definition.
A snap roll is a simultaneous, rapid autorotation in the pitch, yaw and roll axes of flight in a stalled wing attitude. Its initiated by rapid stall of the wing, initiated by a change in the pitch attitude. The nose should show a definite break from the flight path in the direction of the snap while the track closely follows the flight plath.

Typically a nice clean snap will look like this
1. Nose break up or down by a sharp elevator input which stalls the plane. Techincally this is all it shold take to snap the plane.
2. Simultaneous with the pitch break the wing stalls rapidly and violenty.
BUT

That is not hows its done in RC. This is a Radio Controlled airplane forum not a scale airplane forum. The rules of physics are the same, but the planes have bigtime differences in weights and wingloads that make them handle a little differently.

Typically a positive snap, which is initiated by sharp up elevator input, is almost but not quite simultaneously followed with right rudder, right aileron or left rudder left aileron. The right stick will be moved in a real quick U shape and the rudder stick and aileron stick are essentially moved together. With an RC plane the wing loading is usually so light that you get a barrel roll and not a true snap if you dont cheat in a little aileron.

A negative snap is basically the same but the rudder and aileron go in opposite directions and it is normally performed from inverted.

Evidences of a snap

1. Rapid Autorotation..
2. The nose and tail rotate in a conical shape around the CG. Imagine a string stretched tight and the plane is affixed to the string by a cuphook on the belly right at the cg point. The nose and tail will cone around the string, but the cg will rotate right on the cuphook without bending the string...

When you get it there is no mistaking it. A snap is real quick and basically takes on a life of its own somewhat beyond the pilots control for a split second. If the roll is slow and the plane barrels and if you dont see that rapid autorotation caused by the sudden stall of the wing, it is not a stop.