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We're not going to learn how to fly two helis at one time... the photo above is of me goofing around with a picture a friend shot while I was practicing nose-in inverted with my Fury Extreme. I cloned the second heli in Photoshop. I guess that is real advanced aerobatics! I'll explain the setups you need for flying aerobatics below: Collective Pitch: I prefer setting up my IdleUp Flight Mode to be the same whether I'm inverted or upright. I run around 10 degrees top and bottom on my Fury Extreme and Raptor 50 and it seems to work very well. I have the mid-stick set to zero degrees, this way I know exactly where zero degrees is on my stick and I have about 5 degrees positive at 3/4 stick and -5 degrees at 1/4 stick in Idleup. In Normal mode, still run my mid stick pitch at zero and hover at 3/4 stick but I reduce the low stick to -5 degrees and have -2.5 degrees at 1/4 stick. This setup gives me very good transition from spoolup and allows for fast decents in Normal Mode and is enough for basic autorotations. Above half stick my Normal mode pitch curve is identical to my Idleup and my Throttle Hold. This way I can flip from Normal to IdleUp to Hold without any pitch changes above half stick. NORMAL MODE PITCH SETTING: Five Point Curves will be used for simplicity. Point 1 (-5 degrees pitch) LOW STICK Point 2 (-2.5 degrees pitch) 1/4 STICK Point 3 (0 degrees pitch) MID STICK Point 4 (+5 degrees pitch) 3/4 STICK Point 5 (+10 degrees pitch) FULL STICK IDLEUP PITCH SETTING: Five Point Curves will be used for simplicity. Point 1 (-10 degrees pitch) LOW STICK Point 2 (-5 degrees pitch) 1/4 STICK Point 3 (0 degrees pitch) MID STICK Point 4 (+5 degrees pitch) 3/4 STICK Point 5 (+10 degrees pitch) FULL STICK I do have my Throttle Hold setup for +12.5 degrees pitch at maximum pitch. The pitch setting is the same as Normal and Idleup from 90% down to half stick, I modify only the last 10% of the pitch curve to get me a few extra degrees of pitch for making those autos hang a few seconds longer. THROTTLE HOLD PITCH SETTING: Five Point Curves will be used for simplicity. Point 1 (-5 degrees pitch) LOW STICK Point 2 (-2.5 degrees pitch) 1/4 STICK Point 3 (0 degrees pitch) MID STICK Point 4 (+5 degrees pitch) 3/4 STICK Point 5 (+12.5 degrees pitch) FULL STICK Throttle Curve: In Normal Mode, your throttle is idling at low stick (medium idle trim) and full power at high stick. Many beginners learn to hover around mid stick and must transition to 3/4 stick hovering before learning to fly aerobatics. To properly learn aerobatics you must move your hover point from mid stick to 3/4 stick and at 1/4 stick when hovering inverted. You will want to get your headpseed where you want it right side and inverted, this can usually be done with a linear pitch curve and fine tuning the throttle curve. You will want your inverted hover to be the same RPM as when hovering upright. If you don't have a governor (and I highly recommend you get one) you have to set your curves as close to perfect as you can get. Throttle curves become very critical when flipping a ten pound helicopter end over end. You must have the pitch and throttle curves synced so you don't overspeed or bog down. Your helicopter will fly much better if you maintain a constant headspeed, tail rotor response and authority drops along with headspeed. Also the heli will "feel" better, more consistand because it is... Here's a shot of my Futaba 9ZHP throttle curve in IdleUp:
Notice in the photo above you see a V shaped throttle curve. This is what you need in Idleup Mode. You have full throttle at each end of the sticks so you have full power whether you're inverted or not. I have my hover points at 1/4 stick when inverted and 3/4 stick when upright. This gives me a headspeed of around 1850 RPM at hover. The trick is to get the mid point of the curve as low as you can without causing the headspeed to drop too low. You have to be mindful as you decend in IdleUp that the RPM can increase as you decend upright. This throttle curve is for aerobatics and not cruising and landing, flip back into normal mode or flip into Throttle Hold to shoot an autorotation. Servo/Linkage Setup:
You want to get the most out of your mechanical setup and to do that you must be very consistant with your settings. It's very easy to overlook something. Setup your linkages and pushrods so that have minimum drag and zero binding, if it binds either you've got too much pitch and you need to reduce some servo travel with some ATV settings or you have something wrong mechanically.. You have to look at your Cyclic Pitch range in addition to your Collective Pitch. You shouldn't need any more than 6 degrees of Cyclic Pitch. The way to check it is to set up the heli at midstick in Idleup. Your main blades (both) should be exactly at zero degrees and your pushrods and servo arms should all be at right angles to each other when possible. Rotate the main blades until they are 90 degrees to the boom and the flybar is aligned with the boom. From mid stick in IdleUp, apply full forward elevator. Read how much negative pitch is on the left hand blade (assumes a right hand rotation). It is is more or less than -6 degrees adjust the down elevator/forward cyclic to give you -6 degrees at when the right stick is pushed all the way forward. Now go to the right side of the heli and again have the throttle at mid stick and in Idleup mode. Measure the right main blade pitch when you gove full forward on the right stick. It should be +6 degrees. Now, rotate the blades 90 degrees so the blades are in line with the tailboom. Go to the front blade and measure the cyclic pitch, again have the heli in Idleup and the throttle at mid stick. Apply full left cyclic/aileron and measure the pitch, it should be at +6 degrees. The rear blade should read -6 degrees. Depending on what flybar paddles you run and what length of flybar will determine how the heli handles as well as any delta mixing that may or may not be available on the head. You can vary the amount of flybar travel on some helicopters. Even the Raptor 30 has an adjustment for the flybar paddles, It's only a choice of two positions but at least there is adjustment there for those who like to tweak the setup. Heavy paddles will slow down cyclic authority and make the heli seem more stable. The size, thickness and shape of a paddle can really change the way a paddle handles on a particualr heli. I've found the white MA 20gram 3D paddles to be the best bang for the buck. I run them on my Fury Extremes (4mm) and my Raptor 50V2 (3mm) I prefer a stock flybar, some guys like to experiment but I'd rather just fly. I guess I'm not to the point where I want to micro manage that part of my heli. I do run weights on my Fury Extreme. It makes the heli a little smoother and I can use the help. Anything to make me a smoother pilot is good news. I do run -30% Expo on my aileron and elevator (cyclics). I prefer my setup a little softer around hover and center stick. I can slide my flybar weights out toward the paddles if I want to tame it down some or I can pull them back toward the center and increase my cyclic control and speed up my roll and flip rates. |
