Stall turn

[Nick Farrow]

Hi,

 

Having read the recent article I thought I would try to nail these. I have done them occasionaly without putting too much thought to it, however I now find they seem to escape me, when I'm trying. I dont get much flying time so much is down on FMS but it does seem to mimick my failure to make them happen at the field

 

One of serveral things happens

1) Plane stalls, but just falls forward (nods) and seems to ignore the rudder input

2)  Plane stalls and falls back down where is came from for a few meters before pointing fully downward. So a stall turn of sorts but again has nothing to do with me and the rudder

3) Plane stalls but seems to have 'picked' the side to turn that is not the same as I specified with the rudder

4) I seem to have a bit of up elevator still on and it just manages to start a loop.

 

I have tried on a gws p40 and formosa, when I get a chance I will try on my multiplex easy glider (electric)

 

I guess all this is down to subtle reading off how things are progressing that I seem to be misssing. So any pointers would be welcome!

 

Thanks

 

nick

[Chris Bott - Moderator]

Nick to keep control of the tail as you come to a halt in the vertical, you need propwash over the tail surfaces. Sometimes an IC powered model has enough at tickover and sometimes not. If it's an electric model you probably have none at all.

 

You should be able to cure this by either leaving the throttle slightly up, or blip some throttle when the rudder goes in to make it effective. 

 

Or put in the rudder input well before the model stops, however to my mind this produces more of a wingover. 

Edited By Chris Bott on 05/10/2010 14:00:29

[Myron Beaumont]

Cimb up nearly verticaly -reduce the throttle -flick in full rudder -watch it change direction( ie downwards) -open up the throttle - carry on flying !

Simples

[Adrian Smith 1]

Hi Nick, one thing that might be worth checking is if your plane's CG is a little too far forward. I know when I was trying to perfect the stall turn I found the plane I was using was a bit nose heavy. Once I had moved the CG back a tad (not too far - be cautious!) so the plane was a little more unstable I found my plane would do it beautifully.

   

[Ultymate]

Sorry guys but you don't  need motive power to do stall turns they can be executed perfectly with a glider 

[Chris Bott - Moderator]

Yes you can Ulty if your timings perfect. But you won't flick the tail round if you wait until there's no airflow over the rudder. Having some propwash certainly doesn't make it harder.

[Ultymate]

Exactly it's all about timing, if you're after a perfect 10 out of 10 from a judge no sneaky application of power will cut it

[John Privett]

Nick, I never found FMS to be at all realistic with regard to the rudder.  Certainly it wouldn't knife-edge properly when I last used FMS.  I don't remember how it behaved trying stall turns.

[David Bathe]

What you should do is first check you right thrust... you need the air craft to maintain a nice long decent vertical hands off. It to wonders to the left, add some more right thrust to in engine, if it goes right do the opposite. No big deal.. your looking for a plane that'll track reasonably straight.

Once you've got that, go for the stall turn. Thing to remember is: don't throttle all the way back until you've gone over the top and are pointing down. Here how we do it in pattern:

 

Straight and level fight- pull up to vertical- establish vertical heading- start reducing throttle to slow aircraft to stop at the point you want to perform stall turn- Now the Secret...

leave the throttle at 1/3rd power, wait for aircraft to slow down, then just as it stops apply full rudder untill the plane yaws over. As it goes over the top release all rudder and take engine to idle. Let model decend vertically, increase throttle as you pull out to horizontal flight. Bobs your Uncle.

 

You need to allow some engine/prop wash over the rudder to create the yaw.

[andy watson]

This is about the only aerobatic manoeveur I can actually do!!

 

Oh, and a loop.

 

Can't blinkin roll for toffee for some reason.

[Biggles' Elder Brother - Moderator]

All good stuff on stall turns. Nick your description has all the hallmarks of you leaving the rudder too late - so the plane just "flops" whichever way it happens to be leaning.

 

In my experience there are at least two levels to every move. There's the "Ulty level" - in which you do it perfectly - text book. Quite right but requires a lot of practice and skill. We'll leave that to next week  And there's the level the rest of us are at - we just want to do a passable stall turn that doesn't embarass us - right? Afterall if you get the basic one sorted you can always work towards perfection - but in the meantime it would nice if the plane basically did what you wanted. And what you want is a passable version of a stall turn.

 

Here's the quick and dirty guide to stall turns (most of this is above but it will stand some repetition). Make sure your CG is right not just fore and aft but left and right as well. Fly straight and level, open the throttle to max in level flight then pull up (this way you get less torque reaction in the climb pulling you off line). Throttle back to about one third - just before she stops full rudder. As soon as she is at the horizontal position rudder off. Close throttle. Straight down until level with entry point, pull out and open throttle to cruise. Bow to admiring audience. Not text book I know - but it works 99 times out of a 100!

 

Andy - rolls. One trick, pull a little "up" just before you enter the roll. Release it as soon as the model starts to roll. This will work on its own for fairly brisk rolls. If you want to roll slower then a "dab of down" when the model is inverted will help. You'll know you've got it cracked when you exit the same height as you entered. Then try doing two, one immediately after the other as a continuous movement!

 

BEB

[Marc Humphries]

I think a well executed Stall Turn is one of the "prettiest" aerobatic manoeuvers around.  They look even better with a high aspect ratio glider wing.

 

Good technique tip from BEB.

[Ross Clarkson]

I have been practising both the stall turn and the roll on Pheonix Flight Sim for weeks now, i have nailed the stall turn but rolls are much harder but are getting there!

My progress is down to 2 x things, practice and more practice!! This is all after reading the Pilots Notes on the homepage over and over again!

 

I used to think i was able to do them, but after reading up and learning over and over again i realised i was no where near capable of doing them!! Thinking you are doing them right rather than actually doing them right makes a hell of a difference.

 

And i have to agree with Marc, when i thought i could do a stall turn i didnt like them much, now that i can, i agree that they look simply stunning!!

 

[Ross Clarkson]

Also, while we are on the subject sort of, i used to think a roll was merely just whacking the control stick over in one direction!!!

 

Until i read up on it in Pilots Notes i can't get over how hard that actual manouvre is to do properly and i am loving the practice because when i do one perfectly, it also looks so different and beautiful.

 

It makes you realise how easy those competition pilots make it look.

[David Bathe]

Here's an old chip of CPLR flying an F3A routine:

http://www.youtube.com/watch?v=SPuM0Ffphq8&feature=related

Notice how slow and drawn out the areobatics are... not just rushed.

A great tip for beginners is to notice how the aerobatics are joined together with deliberate, straight and level flight. Take your time, don't just fly around in circles, fly an nice straight line infront of you and do a stall turn at each end. When that's in the bag, add a roll, then a loop in the middle. Keep doing the same thing over and over again. What most sports flyers don't understand is that the aerobatic pilots are following a pre-set routine:

Take off, followed by an exact series of 'batics followed by landing. NO deviation!

We all fly the same routine(s) practice and competition. That way one doesn't have to rely on visual reference to see what your model is doing. You know exactly what it's doing because you put it there in exactly the same way you've put it there 1000's of times before.

Difficult to explain. very cool to do. Try a simple routine as mentioned above and your flying will improve 100 fold over adding aerobatics at random.

Edited By David Bathe on 09/11/2010 20:55:22

[fly boy3]

Nice one BEB, best write up of a stall turn I have read for a long time.   Any chance of doing the same on what I am always scared of  - a bunt, or outside loop.  Thanks FB3

Also to David Bathe, I had never thought about routines, but you are100% correct.  FB3

[Biggles' Elder Brother - Moderator]

OK - The BEB guide to the bunt! The Cheap and Cherful way.

 

First thing to remember is that most problems with the bunt are in the mind! It just "feels" all wrong - but once you get the hang of it, its a piece of cake. If your model has the power to loop - then it will bunt, honest!

 

OK first try to get nice and high - if you do make a pig's breakfast of it you want to have plenty of hieght in hand. Next you need to be going downwind - this is so that when you are on the "coming up" bit and you want the lift, you will be flying inverted into wind.

 

Right, here we go. Close the throttle, push in some down elevator. Not too much if you make it too tight you rob yourself of time! I think the problem most folks have is putting on the power too late. I start throttling up at about the 8 o'clock position (assuming you are flying right to left into the bunt). Don't snatch at the throttle - if you do you'll end up with a strong torque reaction which will tend to roll you out of the move. Just a nice steady opening of the throttle is what's called for - steady but purposeful. Now its just a question of holding your nerve while she comes round the bunt.

 

Your first goes at this might look a bit like a "6" rather than a "O" that's beause there is a tendency to "panic" and push in more down to "get it over with"!

 

Final tip - promise yourself that if you do lose your bottle at some point in the middle - you will half-roll out of the move - you must not pull! That way lies disaster.

 

Once you've done a few your confidence will increase and you can bring the move down a bit to a more usual flying height.

 

BEB

[Tim Mackey]

I think we are gonna have to set Mr BEB up as our online aerobatic guru - I like the way he explains it - simple but clear. Nice one Dave.

PS I like doing bunts...but they STILL scare me with anything other than foamy sloper

[Chris Bott - Moderator]

David, many thanks for your last post. It vindicates exactly what I've been doing for perhaps my last dozen flying sessions. Doing exactly what I planned beforehand, is really boosting my confidence, even at the "just beyond B test" level that I'm flying at just at the moment.

[Biggles' Elder Brother - Moderator]

Posted by Tim Mackey - Administrator on 09/11/2010 23:29:16:

I think we are gonna have to set Mr BEB up as our online aerobatic guru - I like the way he explains it - simple but clear. Nice one Dave.

PS I like doing bunts...but they STILL scare me with anything other than foamy sloper

 LOL - I'm certainly no aero guru! I think my only aerobatic talent is to find easier ways of making it look like you know that you're doing! Its the "Faker's Guide to Aeros"! Am sure the real aero experts would shudder at what I suggest  But, hey it works and it makes me happy!

 

BEB

[Lee Smalley]

just a note dont enter the bunt too slowly shut throttle yes but have the airspeed up quite high before entering otherwise you will get a six shaped bunt

[Biggles' Elder Brother - Moderator]

Yeap - Lee's spot on there you need to carry a bit of mometum into the bunt. One other thing I forgot to stress, just as in a loop, you must make sure the wings are level on entry. You can correct as you go round - but it makes life a lot easier if you start off straight in the first place!

 

BEB 

Edited By Biggles' Elder Brother on 10/11/2010 17:30:42

[Ultymate]

You can of course start a bunt from inverted at the bottom . you will then exit inverted at the bottom of your bunt.

[Ultymate]

If you do a negative snap at the top it could be called a negative avalanche.

[Biggles' Elder Brother - Moderator]

Posted by Ultymate on 10/11/2010 17:42:21:
You can of course start a bunt from inverted at the bottom . you will then exit inverted at the bottom of your bunt.

 

Some people actually find that an easier way to learn the bunt!

 

BEB