Wednesday, March 12, 2008

Lessons : Flips

Here I got Flying Lesson From, i'm sure this lesson will help you Guys.....

Lesson objectives:
1. Learn stationary elevator and aileron flips.
2. Incorporation of swashplate mixing.
3. Learn correct collective pitch management to avoid 'over pitching'.

Now that you have mastered inverted flight, then you'll be looking to get onto something different, and the natural progression from there is both elevator and aileron flips.

Although flips are quite easy in concept, like everything else, doing them consistently, controlled, and well can be a little more challenging. Flips make up the basis of a lot of 3D maneuvers and as such, time taken to get them right will help extensively with more advanced maneuvers.

Your heli should have the standard Idle Up 2 (Inverted) setup. It should be able to pull at least 9 degrees pitch both ways in Idle Up 2. Set your pitch curve for 0 degrees at mid stick. Ensure you don't have any binding at full pitch (both positive and negative) while adding in cyclic.
For the throttle curve, start off with something like 100, 70, 50, 70, 100. Remember, you're aiming to hover at points 2 and 4, so you don't want the engine screaming it's nuts off there, I wouldn't recommend anymore than 70% throttle at either of these points.
If your radio has some extra mixers (or if you've got a radio with a dedicated SWASHPLATE function that mixes in throttle with swashplate movements), then become familiar with the use of these functions. They'll become very useful when we get into more advanced aerobatics. We'll discuss the use of this function a little later on.
If you've got a heading hold gyro, it's a good idea to setup Idle Up 2 for heading hold. That way the tail can look after itself while you're trying to come to grips with the cyclic controls.

The concept of a flip is quite simple. For an elevator flip:
· Either push forward or back on elevator as you reduce pitch slowly and smoothly.
· As the heli goes through the vertical plane you should aim to be at about midstick (zero degrees). This will prevent the helicopter moving too much.
· As the heli passes through vertical, you'll be slowly and smoothly adding negative pitch until the heli is fully negative at which point you should be at the inverted hover point (around -4.5 to -5 degrees).
· As the heli passes through inverted back to vertical, you'll again be reducing pitch back to around midstick and then adding the pitch back on as it becomes upright again.

The same steps are true for aileron flips.

· Do not over pitch! If you swing on the collective too much you'll kill both headspeed and engine revs which will take time to come back. An inconsistent headspeed will result in a varying flip rate which will throw your timing off. You'll also probably loose precious altitude!
· Make sure you're straight and level before beginning a flip otherwise the heli will 'walk' or 'run' off in some direction and will make it difficult to control.
· Ensure your gyro is holding well and that your drive system is ok. I did a forward flip with my Standard Vigor the other day only for it to do it's own impromptu piro flip because the tail belt had lost it's teeth! That was exciting I must say and luckily no damage occurred, but it was stress that needent have occurred. If your tail breaks out, do not panic, just continue to follow through with the maneuver until you are upright, then correct, don't try to correct during the maneuver cause you'll just about always screw up (until you have gained more experience).
· To increase your flip rate, ensure that you're getting the most out of your setup first by making sure you have as much cyclic control as you can get without binding, then your next bet is different paddles. My Voyager increased it's flip rate a lot once I installed Hirobo Sceadu paddles, same for my Vigor's with Freya paddles.

Swashplate Mixing:
Something I like to do on my helis for Idle Up 2 is program in a bit of swashplate mixing. What this does is for every cyclic input, the transmitter mixes in a little increased throttle to compensate for the extra loading the cyclic input is putting on the engine.
I use this so that the headspeed is nice and consistent throughout maneuvers, but when hovering either upside down or right side up, the engine isn't screaming too hard.
My radio, the 9Z WCII, has a swashplate function built in, with some of the other radios, you will need to use some of your free mixers to achieve the same result.

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