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Posts Tagged ‘setup’

R/C Helicopters – Blade Pitch Setup In-Depth

July 13, 2010 Leave a comment

Setting up the pitch curve on your helicopter is one of the most crucial parts of setup.

First of all, lets define ‘pitch’. Pitch describes the angular movement of the rotor blades in relation to the horizontal plane. For example, when the angle of the blades is upward, the blades are described as having ‘positive pitch’. Likewise, when the angle of the blades is downward, the blades are described as having ‘negative pitch’.

Rotor Blade in Positive Pitch

Rotor Blade in Positive Pitch

Rotor Blade in Negative Pitch

Rotor Blade in Negative Pitch

Setting up the pitch curve

Once you have read this article, read the tutorial on Helicopter Setup then the tutorial on Radio Setup.

Setting up the pitch curve on your helicopter is one of the most crucial parts of setup. What is a pitch curve you ask? OK…

First up, I’m no aerospace engineer, so I’m not going to give you the physics behind everything. I’m gonna give you the story from my point of view.

First of all, lets define ‘pitch’. Pitch describes the angular movement of the rotor blades in relation to the horizontal plane. For example, when the angle of the blades is upward, the blades are described as having ‘positive pitch’. Likewise, when the angle of the blades is downward, the blades are described as having ‘negative pitch’.

The amount of pitch is measured in degrees above or below the horizontal plane. A normal pitch range for many helicopters is about 22 degrees in total, that’s positive and negative pitch combined.

When the rotor blades get more positive pitch, the helicopter will ascend (climb), likewise, the more negative pitch, the faster it will descend (fall). Unless of course it’s upside down, but we’ll get to that later :).

Now, back to the pitch curve situation. The amount of pitch on the blades is dictated by the position of the collective stick on your transmitter. If your transmitter didn’t have pitch curve point adjustment, you’d have a pitch curve that looks like this:

The graph on the left illustrates a ‘linear’ pitch curve. This means that moving the collective stick along will represent an equal change in the amount of pitch on the blades.

If it weren’t for the provision of pitch curve point adjustment, the amount of change of pitch in the rotor blades would be linear. Meaning that movement of the collective stick would yield equal movement of the pitch on the rotor blades. In some cases, this is fine, but what about if you want to set up different modes of flying? A pitch curve that enables you to hover nicely is probably not going to let you do inverted flying very well. For this you need to be able to adjust your pitch curves.

Most good radios have points on their pitch curves that can be adjustable. The cheaper radios have about three points, good radios have five, while the top-of-the-line radios can have about thirteen. The more points that are adjustable on your radio, the more you will be able to tune your pitch curve.

Most radios also have multiple flight modes. This means, at the flick of a switch, you can change the flight characteristics (pitch curve, throttle curve etc) of your helicopter. So for each flight mode, you can set up different pitch curves that suit different types of flying, hovering, fast forward flight, inverted etc. Flight modes are often called ‘Idle Ups’. Not sure why! Some radios have one idle up mode, others have two, some more advanced can have even more.

You need to set your helicopter’s pitch curves up as well. Make sure you use a pitch gauge to set up your curves. Doing it by eye is just useless.

Linear Pitch Curve

The graph illustrates a 'linear' pitch curve. This means that moving the collective stick along will represent an equal change in the amount of pitch on the blades.

I’ll come back to this later to show you in more detail the type of curves you can create and in what situations they are typically used. For now, that’s it! 🙂

R/C Helicopters – Blade Tracking In-Depth

June 15, 2010 Leave a comment

Hi all,

It’s been a while since my last post, as i had a well deserved holidays period. Now back on track, i will try to recover the time and keep coming to you all with the best and most accurate information i can provide.

This time, i will focus on how to correctly execute the blade tracking setup on a heli. This could be described in just a few lines of text, but i want to fully cover this subject, as this is a key setup action to ensure your heli will be stable and smooth. This is also forgotten or ignored by many practitioners, either by lack of knowledge or by improperly doing it, leading to many flight difficulties that are usually related with incorrect blade tracking and, as a consequence, a very unstable heli.

RC helicopter blade tracking has been a mystery to many new RC helicopter owners, but I’m going to demystify the whole concept for you right now so that you’ll have a complete understanding of blade tracking by the time you finish reading this post.

First, we need to answer this important question: What is blade tracking?

Essentially, blade tracking is when one rotor blade rotates in a circular motion and the following blade follows exactly behind it. Both rotor blades spin on the same plane without one blade being higher or lower than the blade it’s following. Another way to look at it is that both blades travel through the same airspace created by their spinning. If the rear blade is following the front blade on a higher or lower plane, then it can cause a lot of unwanted vibrations for the RC helicopter.

How To Track Your Blades

If you’re flying your RC helicopter for the first time, you need to see if the blades are tracking properly and you may need some help from an experienced RC helicopter pilot. You can check the blade tracking by simply hovering the helicopter in place at eye level and looking at the blades as it hovers. If you see a lot of shaking and vibrating, your RC helicopter is more than likely not tracking properly. If you’re not sure if it’s tracking properly, here are a few simple steps to check it:

  1. get two different colors of tape and apply a small strip of one color to one blade. Put a red strip on one blade and a blue strip on the other blade. By using a different color on each blade, it makes it a lot easier to see which blade might be out of track.
  2. Now that you’ve applied the colored tape, have an experienced RC helicopter pilot hover the helicopter in place so that you can see the blades as they spin. As you watch the blades spin, you’ll know if they’re in track if you only see a single circle or both blades spinning on one line. If you see two circles or two lines, (red above blue or vice versa) then you’ll know that one of the blades is off and needs to be aligned.

Blade Tracking
Blade Tracking

You should always make sure that your blades are balanced before you look at the tracking, as unbalanced blades will effect how they track. I will come back to this subject (blade balancing) in a different post later).

To properly track your rotor blades, you need to land the hovering RC helicopter first. After the blades have stopped spinning, you can adjust the blade that is out of alignment. You’ll need to have your RC helicopter manual handy so that you can look up the proper blade tracking information in it. Be sure that you adjust the correct linkages in what the manual says and not what someone says. This is the best way to be sure that you’ve done it correctly. Usually it involves lengthening the linkage to the blade grip of the rotor that was spinning lower, by removing the ball links and unscrewing them one turn at a time until the tracking is dead on.

If you need to unscrew one blade grip linkage by more than a couple of turns, you might want to tighten the other by a turn or two and alternate until the tracking is perfect.

Once you’ve tightened or loosened the correct linkage or linkages, you need to have someone fly the helicopter again so that you can look at the blades. You’ll repeat this process as often as needed until your blades are tracked properly and they spin on the same plane. Once you’ve completed proper blade tracking, your RC helicopter will handle a lot smoother than it did before and be much easier to fly.

Remember to always use the blade that you did not use to set the pitch with. If you did not use a pitch gauge or do not remember which blade it was, then it depends on how you want to affect the head speed. If you want more head speed, lower the high blade, if you want less head speed, raise the low blade. If you want to maintain the head speed, you have to raise the low blade and lower the high blade by the same amount.

One thing you might want to keep in mind, is that anytime you remove the main rotor blades, you’ll want to keep note of which one goes where to avoid having to readjust the tracking in the future. Also, every time you replace the main rotors, you should check the tracking. I keep a small roll of red tracking tape with me, so I can check the tracking anytime I’m at the field.

RC Helicopters – Getting Started (Part 1)

May 4, 2010 1 comment

I’ve been focused mostly on fixed wing planes until now. But this blog will cover all kinds of radio control flying machines, so i will work along the helicopter fans too – i fly both planes and helis.

RC Scale Helicopter

RC Scale Helicopter

On this first post, i’ll cover the most frequently asked questions beginners usually have when getting into helis. Ready to go? So let’s move on…

What brand helicopter should i buy?

Most of the helis on the market today are good. With any helicopter the good experience you have is almost entirely proportional to how well the helicopter is built and setup. That is why it is so important for people starting out to get help from someone that understands how to best set one up for the flight level you are at. I see this all the time. Just the other day i saw someone with a JR Venture and it was in need of a little help. The guy was having problems with the helicopter not lifting off the ground. This heli has eCCPM and I found that two of the servos were hooked up in the wrong positions. After getting this straight (it was causing the top end pitch to unexpectedly change) then I did my normal setup for throttle curve and pitch curve. I flew it and got the blades in track then set the tail to feel nice. After a half of tank of adjusting I handed the controls to the guy and after this he flew one circuit and kept saying this helicopter has never flown like that before… That made me feel good and is the reason I try to help others .

The point is no matter what helicopter it is, how well they fly is dependent more on how well they are assembled and setup. For me the determining differences between one helicopter versus the other are in how easy they are to work on, how easy it is to get parts, price of parts, and price of kit. And if you have other heli pilots in your area that you plan on getting help from then you should get something they have experience with. Talk to them about the helicopter you are looking at to purchase and make sure they can help you with it.