[gmarsden]

I saw a couple of posts on rollers mixed in another thread, but I thought I would start one on the subject so that it doesn't get lost. Even though I enjoy doing them now, I remember the trials and tribulations of learning them 20+ years ago for the TOC. Because it takes a lot of flight time to perfect them, I taught myself on a smaller plane and I did a lot of them without wearing out my more expensive and larger equipment. Also, depending on your local flying field, the other pilots would probably be less put out by a small quiet plane doing rollers center stage for 10 minutes at a time rather than a big IMAC plane.

Before you start with the rolling, practice rudder skidded circles upright and inverted using about 1/2 rudder and make sure your plane trim and radio mixes are such that there is no rolling or bad pitching tendancies during the skidded circles. I would use your normal cruise power. A little down elevator may required for the inverted version similar to what you would need for straight inverted flight.

With most IMAC planes you will find that the skidded turn radius will not be too large, and in my opinon, when you start adding the rolls, the radius should not get much bigger. From the giant, and do I mean giant, ones I saw at the W/C, not everyone agrees. Although the rule book doesn't offer guidance about the size, if the judge can't see what the A/C is doing because it is so far away, I would think it would affect the ACS score. If you find some video footage of the full size aircraft doing rollers, they haul them around pretty deliberately.

If you are just learning, in my opinion, the next step it to learn how to do rollers with out worrying about rudder. You will lose a little altitude at knife edge so you need to gain it back as you go though wings level. It will end up having a little roller coaster look to it, but it shouldn't look too bad. For you mode 2 flyers, you need to practice learning how to keep the aileron input fixed so that the roll rate is constant while you are moving the stick in the pitch axis. I am pretty sure even with out rudder, you could out score some of the disasters created by wrong rudder I have seen on the contest circuit.

The next step is to add the rudder. Since except for Unlimited, the rolls are always to the inside, what follows applies only to this type. The control inputs are only determined by the bank or roll angle of the plane and not the number of rolls in the circle.
The key thing to remember is that the rudder changes direction as the plane leaves wings level, somewhere around 45 degrees bank. At the start of the circle, the first thing you need is rudder to the inside of the circle to start the skidded turn.

You do not need elevator at the start, or even before the start, otherwise you will climb on the entry and look like a novice, the same applies to the entry of any straight line slow rolling element. I lectured the guys practicing before the NOIC contest about breaking this bad habit, so much that they probably got tired of hearing it, but you have to force yourself to unlearn something you used as a saftey net when you did your first rolls years before.

But I digress, back to the roller, the problem with the rudder you added to start the skidded turn, is that it quickly becomes bottom rudder as the plane rolls away from wings level and down you go. So this is where you need to reverse the rudder so it is top rudder, it happens gradually somewhere about 45 degrees after wing level. When I say wings level, this applies whether you are upright or inverted.

So if you have already commited the aileron and elevator stick movements to muscle memory, all you need to remember is to reverse the rudder soon after wings level, how hard is that

The following are the dominate elevator and rudder inputs for a left roller to the inside. Remember it is continuous blend as the plane rolls and not a step function at each 45 degrees as shown below. There may be subtle rudder or elevator where is not shown below, again, these are the dominate controls.

Control inputs for an inside roller to the left.
Bank Angle Input
=============
0 degrees LR
45 degrees UE
90 degrees UE/RR
135 degrees RR
180 degrees RR
225 degrees DE
270 degrees DE/LR
315 degrees LR

I hope someone finds this helpful and it stimulates further discussion.

Cheers - Greg

[Eye Can Fly]

Thanks Greg, this will really help.

[Billpilotca]

Originally Posted by gmarsden

I lectured the guys practicing before the NOIC contest about breaking this bad habit, so much that they probably got tired of hearing it, but you have to force yourself to unlearn something you used as a saftey net when you did your first rolls years before.

Frank .... any idea who Greg is talking about ??? Must be me, yeah, it was me.

Truthfully Greg your coaching and lectures are appreciated, at least by me. Actually swapping out an elevator servo that had gear train problems and was "sticking" part way through the throw also helped. But your guidance (aka kick in the butt) was certainly appreciated.

Thanks a bunch for taking the time to write this primer out. I am keen to get over this hurdle and will be flying the heck out of my foamies indoors this winter to try and get the fingers doing the right things. That will have to translate to outdoor practice next spring.

I need to read your post 5 more times to make sure I understand it, but one question is do you have a "roller condition" or dual rates set up to help with a consistent aileron roll rate ? I have a roller condition that decreases the aileron movement such that I can throw the stick pretty much all the way either direction and will have a slow enough roll rate that I can get my darn brain to think through what I should be doing with rudder and elevator. The only danger is that if I have to bail out I don't have much aileron throw so I need to quickly throw a switch to get out of the roller condition.

[gmarsden]

Flying mode 4, my aileron stick is with the throttle, so it is easier for me to hold a constant aileron input without having to reduce the aileron sensitivity. Flying Advanced, I don't use any switches, the risk of getting them wrong, especially in unknowns is too much compared to the benefits for me. That said, if I was doing an Unlimited 1 or 2 roll roller, I must admit that I would like a little more rudder and may give in and set up a condition.

I don't think there are many top flyers using full stick, or nearly full stick aileron for rollers. You may want a little expo like curve so that it softer near center. Other than than that, I think you just need to suck it up and learn how to do it part stick. You want to keep the elevator stick sensitivity high enough that you don't need to move the stick too far for elevator where it would be harder to keep the aileron constant.

One word of caution, and this is likely to stir up some controversy, I don't believe in high percentages of expo, to me, it makes it feel too dead and non linear right near center. I never use expo more than about 15%. If this doesn't get the feel I want, I use a multipoint curve with linear section and a break point at 50 to 75% where the rate gets steeper.

Picture attached of my elevator curve, sorry about the rotation.

[LEE]

Great thread Greg! For those of you moving to Intermediate the 90 degree roller ( always to the inside ) is your first intro to this fun maneuver. Watching and judging countless intermediate pilots, the biggest error I see is not finishing the roller 90 degrees to your start point. Also like Greg mentioned, many will bump up ( wether upright or inverted) when they initiate the roll to get that happy feeling that they aren't going to dive into the ground. STOP IT!
Most planes are relatively neutral and a smooth rudder input as you knife edge will often be all you need to keep things level.
The first year I went to intermediate, the 90 degree roller was from the back of the box rolling in. Apparently three pilots at the US Nats lost their planes that year!

[Billpilotca]

Originally Posted by gmarsden

I don't think there are many top flyers using full stick, or nearly full stick aileron for rollers. You may want a little expo like curve so that it softer near center.

Ok well you are one of the most talented Advanced pilots we have so I respect that. I also understand your skills come from a lot of dedicated hard work and practice. Something we all can learn from.

I do understand that a number of top pilots do use roller conditions but perhaps not as extreme as what I indicated. Hopefully some of them can chime in. Truthfully I may need to "suck it up" however I am also trying to use the computer radio capabilities to make it work best for me. I also understand that there are some top guys that use virtually no conditions at all and fly purely with the sticks. I admire that skill, unfortunately I don't have it.

Thanks for taking the time. It is very helpful.

[garyr1]

Thanks for taking the time to break this down Greg.
Learning this move is certainly a challenge. That's not a bad thing.
I'm miffed that I spent much of my time over the last 12 months working on outside rollers...that's what was detailed out in the Dave Scott Aerobatics books I used to get started. It's the old story: I don't know what I don't know.
It's really, really HARD at first to get the inside one going after learning the outside but it is starting to come. (my wife is convinced I'm loosing it, swearing at the computer so much...)
Hey, it's gonna be a loooong winter, and my sim and I enjoy each other's company, so as long as I don't wear out the reset button, I'm rocking!
Thanks for starting this up...it's great to tap into the brain trust out there.

[gmarsden]

Bill

I wasn't suggesting that you get rid of the condition switch, just that you don't use it to radically desensitise the aileron such that you need almost full stick to do a roller and need to hit the switch to bail out. During normal flying, you have conditioned your reflexes to expect a certain stick/aircraft response, and I think you are doing yourself a disservice by altering it so drastically.

While calling for Bryan M., I noticed he has his radio set up to repeatedly say a phrase while a condition is active, it seems like a good idea to ensure you don't forget to turn off the condition after the roller.

Cheers - Greg

[LEE]

Originally Posted by gmarsden

Bill

I wasn't suggesting that you get rid of the condition switch, just that you don't use it to radically desensitise the aileron such that you need almost full stick to do a roller and need to hit the switch to bail out. During normal flying, you have conditioned your reflexes to expect a certain stick/aircraft response, and I think you are doing yourself a disservice by altering it so drastically.

While calling for Brian M., I noticed he has his radio set up to repeatedly say a phrase while a condition is active, it seems like a good idea to ensure you don't forget to turn off the condition after the roller.

Cheers - Greg

A good point on the voice cue. I have one for my hammer condition and also one for landing. You should not look down to activate a switch and if your radio has the voice feature it's a really great way to remind you of where things are.
I have a roller condition but I don't use it anymore as I got used to flying things through with regular rates, so the only switch I have is for my hammer which gives more rudder.

[Billpilotca]

Originally Posted by LEE

You should not look down to activate a switch and if your radio has the voice feature it's a really great way to remind you of where things are.

I use one three position switch when flying, it is a top right with that I can flick easily with my index finger without looking. I standardized on it several years ago after trying several switches. I don't need to take my thumb off the stick to change conditions and it works for me. I use one other switch to idle down for landing. My snap conditions are all stick position triggered so no switching involved.

Originally Posted by gmarsden

I wasn't suggesting that you get rid of the condition switch, just that you don't use it to radically desensitise the aileron such that you need almost full stick to do a roller and need to hit the switch to bail out.

Fair enough. I just cannot seem to coordinate my left and right thumbs to work together at the right times. I can hold the aileron more or less constant and use elevator, or hold the aileron and use rudder, but holding the aileron constant and use elevator and rudder in sequence at the right moments, geeeezz!! Kind of like that old deal of patting your head and rubbing your belly at the same time. I am too darn spastic !!