Wow, circles are so hard. Any tips?

[clank72]

I'm using RealFlight 5.5

Hovor: No problem.
Nose in: Can do it in my sleep.
Flips: No problem.
Land Anywhere smoothly: No problem.

Circles: What the hell?

This is VERY hard for me. I'm trying to perform low level circles over the runway. The flight instructor on Realflight makes it look so easy. He just says "Point the nose down and move the rudder slowly". Yeah right.

Any tips? I know, just more practice I guess.

[marty_one]

best tip I can give is start in a clock wise direction, as the torque in the motor adds a natural lean to the heli that makes clock wise circles fairly easy to do.

can you do forward flight from one side to the other and back again? this for me is what made the transition to clockwise circles easier.

anti-clockwise circles are a little harder, as you have to go against the natural lean of the heli.

[Suburban92]

fly it like a plane.. add rudder to track tail with nose

[clank72]

Thanks!

I can do zig zagging at a higher altitude (fly to the left, turn around, then fly to the right, along the run way). I wil try these tips. Thanks!

[danyl]

There is a tendency to enter your turn with too much aileron and rudder, which makes the beginning more of a 90 deg affair. This becomes problematic to correct for later. Start with very limited aileron and slow, but steady rudder. This will also reduce the need for as much up elevator. Getting the rudder around seems to be the hardest part. I would personally over compensate the rudder. Even if it makes the last part of your circle into a piro. At least then, you can gradually take out the amount of rudder you use.

The other noobie problem with circles is a wide drift sideways as you complete the last quarter of the circle. It's referred to as an "increasing radius turn". And isn't what you want.

This occurs because the aileron input during the nose-in part of the circle is opposite that of the tail-in portion. The aileron input as you turn away from yourself in the last quarter will need to be increased from the amount you are already putting in.

There are of course many ways to skin a cat, but this is mine. best of luck

[LN400]

Just an idea: To turn the heli 90 deg, three things need to happen. The velocity in the "old" direction needs to be slowed down (cyclic opposite of flight direction), the velocity in the "new" direction needs to increase (cyclic in the wanted direction) and the helicopter needs to be turned using the tail rotor, clockwise or counter clockwise.

As for the cyclic, if you combine those two directions in forward flight (opposite of the old direction, into the wanted direction) you end up having to push the cyclic 135 degrees from up-cyclic, that is 45 deg down/left (and ccw rudder) or 45 deg down/right (and cw rudder). A heli is not stable at all and will need corrections all the time so these angels for the cyclic are just starting points that need to be adjusted.

The thing here is, if you want to bank turn in sideways flight, the exact same thing applies. If you look at rightwards flight and you want say, a left turn (ccw), slowing down the old velocity is left cyclic, speeding up in the new direction is up cyclic and the two combined gives 135 deg ccw from right cyclic, that is 45 deg up left, with ccw (left) rudder.

Use this as a starting point but remember you need to continuously adjust.

[clank72]

LN400, thanks for the response. I think I might need a bachelors degree in physics to decode your reply.

I will be practicing the sim.

[floop]

Here is a video describing what to work on. Circles will teach you better orientation and control. It takes some getting used to.

[rob56]

I wish I could stop doing circles I want to hover (on a sim)

[questerng]

Hi,

Just to share what I've found out that could help in flying circle..

1. imagine there's a clock facing the sky in front of you.. You'll have your 12 furthest from you, 6 closest to you.. and 3 is on your right side and 9 is your left side..

let say we start flying upright CW..

2. start with nose facing left at 6 hovering.. fly to 9 and have the heli facing front when you reach 9.. hover there for a moment..

3.From there fly a to reach 12 with the nose facing right when you reach 12.. hover for awhile..

4.Then fly to 3, and when you reach 3 your heli should be nose in.. hover there for awhile

5. finally fly to 6 again.. you should be back to where you start off..

you will need to fly like your are making a turn to achieve the desire result.

this exercise will help you to orientate all the different turn from all the diff positon.. ( or at lease it help me..) before you know it you'll be flying in circle..

once you get your upright down.. try tail, inverted nose and inverted tail..then try CCW..

Hope this help

Merry Christmas to all..

quest

[Innovine]

I like to do it like this: (I think CCW is easier..)

Start flying from left to right at a good speed. After the heli passes you, bank it around 45 or 50 degrees left. It'll start to lose altitude, so apply a little more collective and pull back on the cyclic to raise the nose a little. This will give altitude, and also control how tight the turn is. At the same time, apply rudder so the tail follows along behind the helis flight path. Now the hard part is just waiting as it turns nose in and does the last quarter of the circle. It's easy to overcorrect and screw things up here, so I find it helpful not to do much besides wait as the heli comes around. Keep the bank angle steady, and occasionally pull up the nose or relax it a little to tighten or loosen the circle. Lots of practice and it starts to get smoother.. it might also help to do ovals or circuits first, before combining both turns into a circle.

[dfraser]

Thanks for this thread! It's good to know I'm not alone. I totally fall to pieces when I try to do a nice smooth circle in the sim. I either end up flying all over the field or crashing... It's a mess. Often I end up with too much or not enough aileron or tail, and end up sliding sideways, doing a slow piro, flying backwards, etc.

I've noticed that I have to give a bit of up-elevator constantly during the circle to keep things smooth and level. Is that normal?

[ki4bbl]

Absolutely. When you are in an aileron turn, you will bleed off altitude if you do not adjust for elevator. I have flown both a real h46(automatic coordinated turns) and an H3 (coordinated turn needs yaw, collective, and cyclic to keep from slipping) and it is just like the rc bird. Helicopters take a lot of coordination to keep aloft...especially in a coordinated turn.

Greg

[dfraser]

I was having fun flying around in the sim today using only the cyclic control... I had the gyro in rate mode and the collective stick set at about 75%... Trying to maintain a constant altitude and not crash. It was a lot of fun!

[circle jerk]

I think understanding how an actual helicopter really flies may help in answering a lot of problems for many R/C pilots. I'll try but I'm not a professional teacher, just a professional R/W pilot/engineer. All figures will be hypothetical and swash plate will be important.
Here goes!
Only the blades on a helicopter provide lift; on R/C helis this happens one of two ways, fixed pitch blades which mean you have to increase the speed of blades to create lift, or collective pitch which means that your blade speed remains constant and the pitch of the blade increases to give you lift. Simple enough, I hope!.
Now, think of your blades working this way. Regardless of whether your blades turn clockwise or counterclockwise, the forward moving blades provide more lift than the retreating blades do, thus the need for a swashplate. The swashplate causes the retreating blades to increase pitch in the retreating motion and the advancing blade to decrease pitch in order to equalize and balance the heli. Next, try to picture the following.
Lets say you are flying forward at 100 m.p.h. and your blades are turning at a speed of 400m.p.h.( constant ). In total your forward moving blades are now travelling at a total speed of 500 m.p.h.BUT your retreating blades are now only turning at 400 m.p.h. less your forward speed of 100 m.p.h. because they are now going backward, thus your retreating blades are providing much less lift than your forward blades. This is where the swashplate comes into effect to offset the diminished lift of the retreating blades. The swashplate causes the retreating blades to increase pitch in order to prevent the helicopter from dipping to one side and eventually tipping over. Now remember this is in forward flight. So, what happens when you start to make a turn. The outboard blades are creating more lift than the inboard blades because when turning in a circle the outboard blades go even faster than the inboard blades. All of a sudden the heli wants to start dipping to the side that has the least lift, meaning the pilot has to compensate for this in different ways i.e. using tail rotor torque increases to help the heli turn, pulling back on the cyclic to keep the nose up and also pushing the cyclic to the direction of turn to maintain heading, and lastly, using an increase in collective pitch to stop the drop momentum caused by the loss of speed (forward speed)of the rotor blades; (both forward and retreating) which, in summary,want to cause a loss of lift.In the case of a fixed pitch give a little rotor speed increase in lieu of collective pitch increase.
So, on a fixed pitch rotor, some rotor speed increase would be necessary, faster tail rotor input to get the heli turned and some cyclic control inputs @ to initiate heading change and to keep the nose up.
The gist of all of this is simple, remember that advancing blades provide more lift than retreating blades so, whenever the direction of a heli wants to be changed the lift characteristics of the forward vs. retreating blades causes multiple rquirements for input changes and that these changes are very, very, relative to whether the heli is a fixed pich heli vs a collective pitch heli. ( no real helis are fixed pitch ) If the foregoing is understandable, hopefully it helps and not screws everyone up!
Further, remember, whenever power is applied to the rotor, power must also be applied to the tail rotor to offset the increase in torque which if not done would cause your heli to want to turn on its own axis. This is a more problematic situation on motor equipped tail rotors because the motor tends to build in lag time, causing the heli to most likey overswing in the tail before the motor kicks in to counteract torque.
I pray this info helps and not hinders!!
Cheers

[BaconRaygun]

Your thinking of a flapping hinge man, our helis don’t have those... The swash plate transfers control inputs from the pilot to the head... It really has nothing to do with dissymmetry of lift.

But yeh, left and right turns are different because of dissymmetry of lift.

Also, you don’t continue giving cyclic input in the direction of the turn, in fact when you are doing circles you are pretty much giving it opposite cyclic the whole time.

Another thing... The retarding blade loses around 2/3 less lift then the advancing blade gains so the difference is not linear but the faster you go the more pronounced this effect becomes. Fortunately for us this is not that noticeable with our RC helicopters, partly because of the bell/hiller head design and partly because the speeds we achieve vs the RPM of the rotor head is fairly low. Many RC guys can go their entire flying career without ever noticing dissymmetry of lift.

[danyl]

I personally love the mental masturbation of dysemmetry-of-lift, but I don't think it has anything to do with a noob's difficulty in mastering circles. He simply needs advice on stick inputs. The difference between good teachers and bad teacher has little to do with their knowledge. It has everything to do with their ability to relate to the student! The fact that this thread has been hijacked into a physics discussion is disrespectful to the initial inquiry.

Both of you seem to have a very nice understanding of heli physics. It might make a marvelous group on helifreak.

One correction though: (I can't resist either) Our helicopters DO have flapping blades! They are not fully rigid, they are semi rigid. They flap using the teeter-totter principle, but instead of a hinged teeter like the Robinson, the feathering shaft is free to flex in the headblock. That's what the dampers are there for! They control the flapping!

[BaconRaygun]

Originally Posted by danyl

I personally love the mental masturbation of dysemmetry-of-lift, but I don't think it has anything to do with a noob's difficulty in mastering circles. He simply needs advice on stick inputs. The difference between good teachers and bad teacher has little to do with their knowledge. It has everything to do with their ability to relate to the student! The fact that this thread has been hijacked into a physics discussion is disrespectful to the initial inquiry.

Both of you seem to have a very nice understanding of heli physics. It might make a marvelous group on helifreak.

One correction though: (I can't resist either) Our helicopters DO have flapping blades! They are not fully rigid, they are semi rigid. They flap using the teeter-totter principle, but instead of a hinged teeter like the Robinson, the feathering shaft is free to flex in the headblock. That's what the dampers are there for! They control the flapping!

Yep, Dampers and blade flex is our flapping hinge...

Circles...

-With a CW rotating head, right hand circles (and turns) are more natural so start with right hand circles.

-Initiate the roll, just like you would with a regular turn...

-Find the right pitch angle for the circle you would like to do, this stays pretty constant throughout the circle

-Now, you need to feather (very small adjustments) the tail AND aileron inputs to find the sweet spot, aileron input will be almost opposite of your initial input when starting the circle.

* During the circle

-If the nose starts to dive let off on the rudder a bit and give more opposite aileron.

-If the nose starts to rise give it more rudder and less opposite aileron (remember, pitch stays pretty much constant)...

-When you are in a turn your rudder has more of an influence on altitude then your pitch and aileron.

-Your collective pitch stays pretty constant, more pitch and you broaden the circle and put forth the need to alter your pitch angle otherwise you will actually start to lose lift and your heli will start to fall sideways. Less collective and you lose lift and start to descend vertically.

You should be able to find a 'sweet spot', once you do (assuming ideal weather conditions) the heli will keep flying the circle and you're sticks will be glued into a set position. It’s all about finding that 'sweet spot' and training your brain and muscles to know exactly how to get there smoothly.

Last but not least, practice, practice, practice!!!!!

[danyl]

^^

Wow. That helped me too! Kudos

[TallPaul]

I can also recommend I Heart Heli lesson #9 and on. http://www.iheartheli.com/content/view/107/44/1/11/

He demonstrates some of the forces and the reasons the heli reacts the way it does. Truthfully, his frisbee on the stick is a little bizarre, but it works.