Competition Turns

[paulo]

(Reading Alan Cassidy's Better Aerobatics the other day, I discovered that the competition turn was not what I thought it was. Coordinated turn? No. Points off. Bad pilot. You establish bank whilst staying on your entry heading, then do the turn.)

I had a try today in an R2160. Right aileron, balance with left boot. Nimble though the Robin is by spamcan standards, it does become the flying anvil in certain aerobatic maneouvres (inverted, it's either two handed, or better still, use a spare foot on the stick :)

Full straining left rudder I think I managed about 40 degrees bank tops, any more it was going to turn. Tried a few more times using a bit more forward stick to arrest the turning tendancy, but only did marginally better.

So, anyone got any tips for low powered aeros mounts? Is there anyway of holding 60 degrees bank? Or is it just a given that you'll never really get there and so beyond, say, 45, you accept the inevitable and make the turn?

[Miserlou]

I've not flown the Robin so can't help other than to suggest that you also consider the speed required for the manouvre. It is an aerobatic manouvre and therefore requires that you enter it at the correct speed. This is the first key.

The second depends on the accelerometer, 60 bank requires 2g to maintain level flight. If you're pulling harder, you're wasting speed.

[paulo]

Miser - re-read, should be 1g as you get established -

You might be thinking of max rate turn as I used to think of them (i.e. in the coordinated turn sense). The comp turn requires that you do the opposite, at least initially. So, right turn, left boot, so you get the bank without initiating the turn. They actually, so I read, go as far as deducting points if you turn as you bank.

Didn't really consider entry speed - wonder if faster is better for the out-of-balance transition?

[djpil]

Two points for you to consider:
1. treat that initial roll as you would the first part of a slow roll - roll quickly to 60 deg bank
2. the turn has a very low K factor so it doesn't matter a whole lot if its not perfect, not that I'm sugegsting that you throw points away but use it to maximise points in other areas i.e. what figure is next? do you need to descend during the turn to exit at a particular speed? where are you in the box?
There is simplified judging criteria at the BAeA website (http://www.aerobatics.org.uk/judging/Judging%20School.htm)

[paulo]

dj - cheers; I guess my only exit consideration right now is the beginners sequence (i.e. post 270 comp turn, it's an aileron roll straight at the judging line)... but as you say, maybe it's more the figure as a whole, so sod the perfect entry (esp. if it can't be done in my choice of machine)

[djpil]

You should be able to do it in the Robin without much penalty on the entry if the roll to the 60 deg angle is brisk and you make a good effort to avoid yawing or change in height. I haven't flown one but often judged them.

[FlyingForFun]

Hope I'm not going to embarass myself too much by talking about things that I don't know very much about. Mind you, it wouldn't be the first time....Right aileron, balance with left bootReally? On all the aircraft that I've done this one (Great Lakes, Pitts Special, and a bit of practice in a Super Cub), for a right turn, I've used right rudder to counteract adverse yaw. Not quite enough to keep it coordinated, because like you say that would result in the aircraft turning to the right before you're ready for it to do so. But if you were to use right aileron with no rudder, the aircraft would initially yaw to the left, so therefore you must need right rudder to counteract this?

Or, to look at it another way - is the turn entry not the same as the upright part of a slow roll (as djpil says)? And don't you use rudder in the same direction as aileron in the upright part of a slow roll?

Ok, I'll shut up now and let the people who actually know about aerobatics correct me! :D

FFF
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[Miserlou]

I read it again but didn't think it worthy of a pedantic reply to the effect that the positive g loading during the entry must be less than 1, reducing to 0.5 at the 60 degree bank, then instantaniously increasing to 2g during the turn.

Re-reading your description, I would suggest raising the nose slighty just before you introduce the bank. This should be a fluid motion and you should be using full aileron for the roll.

The aircraft is not required to maintain this attitude. The turn MUST start as soon as you reach the required bank angle.

[paulo]

With you miser - sorry, thought you had misunderstood.

FFF - [Sigh]. There's always one isn't there? ;) Hmmm. Yes, I see what you're getting at. The adverse yaw on full aileron deflection is going to be fairly momentary? Maybe there's a case for a brief dab on 'bottom' rudder on the tip in, then a boot load of top to the point where it's turning regardless, then slowly release to get a smooth transition to the turn proper.

I get the feeling I'll be mailing Mr Cassidy quite soon. :D

[FlyingForFun]

There's always one isn't there?Yep! ;)

[Aerobatic Flyer]

Paulo

If the judges are to one side of you they're probably not going to notice a small change in heading in the time it takes you to roll to 60° of bank.

You want to get the bank on as quickly as you can. You'll probably find that this is easiest if you use rudder in the same direction as the bank to counter any adverse yaw. If you use opposite rudder, you'll exacerbate the adverse yaw, reduce your rate of roll and either lose height or speed.

Depending on the position of the judges, the other thing you can try is cheating! When drawing the line before the turn, you can yaw the aircraft slightly while holding the wings level. On appling aileron, with a bit of luck you'll reach 60° of bank just as the nose comes through the entry heading.

Have fun practising!

[paulo]

Heh heh... Cheers Aero Flyer... it gets better and better :E


The great thing is that Mr Cassidy actually covers 'cheating' in his book, so I'm sure he won't be offended if I run this by him.
:ok: