Written by Greg Gimlick How-to As seen in the Winter 2017 issue of Park Pilot.
Maybe I should write de-tuning because I’m going to discuss how to tune a helicopter so that it’s appropriate for beginners. Most online information concerns tuning to increase performance, but if you are a beginner, you need a more stable, less sporty machine. The abundance of email I’ve received points to interest in tuning down a 450-size helicopter, but these tips will work for most sizes. I’ll break the points into specific areas of concern.
Rpm: Some of the helis you see and hear at the field sound like angry hives of bees on a rampage. The 3-D pilots run impressively high rpm, but you don’t need that. I use the governor function of my Castle Creations (castlecreations.com) controllers and set three rpm levels for various modes. (Note that the terms idle up and stunt are used interchangeably depending on the source.) • Normal: 2,400 rpm • Stunt 1 or idle up 1: 2,600 rpm • Stunt 2 or idle up 2: 2,800 rpm
On a 450-size heli, these give a reasonable main rotor rpm that also provides stability and control authority.
Flybar weights: Flybarless helicopters are predominant today, but on flybar-equipped helis, you can enhance stability with flybar weights. You can even double the flybar weights for better stability. The idea behind adding weight to the flybar or paddles is to reduce the responsiveness of the cyclic controls. Weighted paddles are available from third-party suppliers, or some use wheel collars on the bar. Wheel collars must be the same weight and must be attached so that the flybar remains balanced. A nice benefit to using weights is that they can be positioned at various points along the bar to fine-tune the effects. The farther out on the bar, the more effective the weight will be in reducing the response. Increasing rotational mass can have a huge effect. Be sure that there is no way that a weight can come loose or shift position.
Greg’s Swift 16 employs aftermarket Hirobo weighted paddles to add stability.
The 450-size heli inside this Hughes 500 scale body is toned down by the use of the flybar weights that are seen near the end of the paddles.
Pitch and Pitch Curves: As a beginner, you don’t need maximum positive and negative pitch like 3-D fliers do. You need enough to maintain solid control, but not so much negative pitch that you are constantly slamming into the earth. As a fixed-wing pilot, you develop a habit of rapidly reducing throttle when you think you’re about to crash. On a helicopter with negative pitch, reducing the throttle will accelerate your arrival at the crash scene. I don’t advocate taking all of the negative pitch out, because you don’t want to develop a habit of not paying attention to it. As you progress, you will increase the available negative pitch, so it’s important to learn about its effects from the start. One thing to remember is to always set your pitch to zero degrees at mid stick. This is important to establish early so that no negative habits develop before progressing beyond the basic flight modes. Here are a couple of guidelines for beginner pitch/curve settings. Remember, these are recommendations for starting points and are conservative; you can dial them up later. • Normal: 40%, 45%, 50%, 70%, 90% • Stunt 1 or idle up 1: 10%, 30%, 50%, 70%, 90% • Stunt 2 or idle up 2: 0%, 25%, 50%, 75%, 100% These settings allow a beginner to have three increasingly more-aggressive settings without jumping all at once from beginner settings to 3-D. Remember, you’re learning to crawl before you walk. The purpose of having 40% and 45% as the first two steps in normal settings is to reduce the amount of negative pitch and make it easier to land from a hover.
Here is a sample of one of Greg’s pitch/curve settings for normal mode.
Throttle curves: Few areas cause more confusion and arguments than throttle curves. These are guidelines to get started if you’re a beginner. Remember that I use the governor function of my ESC, so the first set of numbers reflects what I use to attain the rpm previously listed. • Normal: 0%, 30%, 30%, 30%, 30% • Stunt 1: 70%, 70%, 70%, 70%, 70% • Stunt 2: 100%, 100%, 100%, 100%, 100%
This is the Stunt 2 throttle curve for one of Greg’s toned-down, non-governor, 450-size helis.
These settings are for my Castle Creations ESC governor and work well as a starting point. If you are using a different governor, adjust as necessary to achieve your expected rpm for each flight mode. For those of you who are not using a governor, here are some recommended settings to get started. • Normal: 0%, 50%, 80%, 90%, 100% • Stunt 1: 100%, 95%, 90%, 95%, 100% • Stunt 2: 100%, 100%, 100%, 100%, 100% You might wonder why the Stunt 1 mode has a lower number in the middle. Remember that mid stick is zero pitch, so there is less load on the system than at the other ends. This requires less power to maintain a steady rpm through the range of motion. In Stunt 2, it’s 100% across the board—the hardcore 3-D pilots need that available to them at all times. I’m out of space, but there’s much more to cover. This should get you over the first setup hurdles and hopefully answers the questions that I’m receiving in your emails. Keep the questions coming! --Greg Gimlick
