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How-To: Inverted with Video
I figure there's probably enough interest on this topic to warrant an inverted how-to. So here goes...Pre-requisites
You should have fairly good control of the helicopter at this point. Hovering in all orientations, circuits, funnels, backwards flight, loops, rolls, nose in, stationary pirouettes should all be in your repertoire before starting the task of inverted. If you need to work on any of these items come back later as you need a solid foundation of control before layering on yet another set of complicated orientations....That being said, welcome to Inverted 101You should at least be comfortable with a little "inverted" by now if you can do loops and rolls. You know at least how to give a little negative pitch when inverted to keep the heli from crashing to the ground.Learning process
There really isn't a lot to "teach" about inverted but I will give you a bunch of pointers that will make the learning process (maybe) a little easier for you. Also you should know that taking 6 months or more to even start to get comfortable at inverted is actually fast learning. If you work hard 6 months is a very attainable goal, but expect up to a year or more if you are not actively practicing on a regular basis.What I'm trying to say you're only enemy with learning inverted is time. Even using a sim diligently you will need to put a lot of time and effort into learning well controlled inverted hovering. Learning forward or backward flight is an even bigger step (IMHO) so relax and work at your own pace. It will not come quickly, but you will get out of it what you put into it.Simming
First off, if you don't have a sim by now, get one. Sorry but the fact is sims are a very effective learning tool, that saves a lot of time and money. What sim to use is up to you. See the 1000 different threads here on RR on that topic, but whatever floats your boat is what I say. Flight time is flight time especially when just practicing orientations. All the sims (even the really bad ones) all work the same. Move stick left heli leans left. Good enuf, but I digress... Get a sim and use it.If you refuse to get one, or can't use one that's ok, but expect the learning process to take a bit longer. You will need to practice everything with your real setup which means a lot less stick time (sims can be used 24/7 in any weather), plus you will likely crash a cpl times. But don't fret, just keep it high and keep at it.Most sims have some kind of inverted practice trainer game. They are ok, but I don't recommend getting too attached to it. Just get in the air in an idle up mode and flip her over and work on stability.Flip it
Flip or roll to inverted however is comfortable for you. Personally I like to backflip to an inverted nose-in orientation, but you do run the risk of using too much positive pitch and flying the heli over your head so keep the heli a good distance from you if you prefer backflips. When you do your flip start with a little positive to get the inertia of the heli moving upwards. As you roll quickly transition the collective to mid stick/zero pitch and as you finish the flip end with a tad below mid-stick amount of negative pitch. You really do not need a lot of negative pitch for hovering (no more than positive pitch for upright hovering) but it will take a bit of practice to find that sweet spot.Reversed Controls
When you are inverted a few of the controls will get "reversed" from what you are used to when hovering upright. I'll list them and then I'll list some tips on overcoming the changes.1. Rudder - If you normally "fly the nose" when you are hovering upright, then you are used to using for example left rudder, and whatever part of the heli is furthest away from you points to the left. So if the heli is tail in, then the nose (furthest away) points to the left. This will be reversed when inverted.
2. Elevator - Normally you pull back to make the nose go up. Now pulling back will make the nose go down.
3. Collective - Down is up and up is down Don't ever get this one mixed up hehe.Notice I didn't mention ailerons. Aileron controls are not affected by being inverted. If you are inverted tail in then giving right aileron will roll the heli to the right. How convienient!!! One less thing to worry aboutRudder
To overcome the rudder being reversed look at what part of the heli is closest to you. So if the heli is nose in look at the nose. If you want that nose to point to the left, then give some left rudder. If the heli is tail in then left will make the tail go left. Point being is the part if the heli that is closest to you will move in the direction of the rudder you use. In normal upright flight this would be called "flying the tail" which some people do. When those people go inverted they have to switch to flying the nose.Elevator
To overcome the elevator reverse, I always just pictured the tail as just being the nose. Forget about the actual nose, it's useless, look at the tail. Pull back and the tail goes up. Push forward and it goes down. Hey that's just like the nose when upright hovering!! Point... The tail is the new nose. Don't forget that and the elevator will be a snap to get used to.Side note: Because the inverted tail acts like the upright nose, I always found inverted tail forward flight much easier than nose forward flight. Pull back and heli go up. Push forward heli go down. It's just less confusing.Collective
Not too much to say about collective. It will just take time to get used to the stick being below center when inverted. Normally when upright UP is your friend to bail out and fly higher in the air. Now DOWN stick will be your bail out direction. Get that wrong and you'll have a weekend of wrenching to look forward toPractice Practice Practice
Well as I said you will need to practice a LOT. Keep at it and slowly but surely comfort and control will come.Pirouetting while hovering
This will probably be one of the hardest skills you will have ever learned in your life (not really joking here ) I've learned a lot of different skills in my life, but this without a doubt ranks up at the top of the difficulty meter. Hovering inverted is hard enough, but now do it while the heli is spinning around... Yeah, you get the idea. However this is an essential skill that you will simply need to put hours of practice into. Work on piroing in both directions, but it's ok if you get a little better at one direction than the other, just make sure at least to work on both. Also, keep them very slow. About one revolution every 10 or so seconds at most. As you get better you can speed them up, but when you are starting keeping them slow will teach you a lot more (I.E. it's harder).Although this is extremely hard to do (and also very frustrating at times) there is light at the end of the tunnel, and the more you practice the easier it will get. Eventually you'll forget why it was hard and it will actually be easy and natural to do. Just put in the time and you'll get there.Forward and Backward Flight
Actually flying forward or backward while inverted is a whole 'nother animal. You will need months to get used to hovering alone, and I honestly do not suggest practicing forward inverted flying until you are very much in control of hovering and stationary piros first. The better you are at piroing in place, the less likely you will find yourself in a confusing dumb thumb situation later when you are flying around.If you have an airplane background (and could fly well inverted) that will certainly help learn heli nose forward inverted as it's nearly identical. But hold off for a while and get the control down first.I recommend starting with a controlled hover in front of you then slowly use a little rudder and use the cyclic to follow the heli around in a circle as the heli piros round. This is why learning to hover a slow piro is so critical. Once you can piro in place forward or backward flight will be a piece of cake.Coordinations
In a different How-To I talk about what I call "coordinations", that being how the rudder and aileron sticks work together when forward or backwards flying. As I mentioned in that post inverted flying will have the opposite coordination than upright flying. When flying nose forward rudder and aileron will be uncoordinated (opposite directions) and tail forward flying will be coordinated (same direction). Try to keep that in mind when starting out and it may help you in a moment of "what do I do!" and remove some of the early learning dumb thumbs.----Well there's a lot of text here. More than I anticipated writing when I started, but it's useful stuff. Mostly what I went though when learning. The end goal while far away is not so impossible to attain, just keep working at it, and keep it fun.Good luck, and keep practicing!
|01-02-2013 08:34 PM|
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How-To: Inverted with Video