Author: Mark Fadely
Edition: Model Aviation - 2008/01
Page Numbers: 119,120,121,123
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Radio Control Helicopters - 2008/01

Mark Fadely [[email protected]]

Indoor flying season is here; check out an event in your area

Now that we are in the full grip of winter, it is a good time to discuss indoor electric models. I have included some pictures from E-Fest 2007 to get you excited about that event.

Unless you just entered the hobby, you probably know that micro electrics have been the fastest-growing segment for some time. Along with being cheaper, easier to fix, and safer, they are tons of fun to fly.

New indoor events are popping up like mushrooms across the country. Enthusiastic electric-power fliers are making deals with building owners to use their space for RC aircraft. There is nothing like having a large, heated area in which to fly when it is cold outside.

There are two major indoor events in the Midwest around this time:

  • The JR Indoor Electric Festival was held November 2–4 in Columbus, Ohio.
  • The Great Planes E-Fest will take place February 9–10.

I heard a rumor that there is going to be a mega indoor fun-fly in the University of Phoenix football dome this year. Now that is taking it to the next level for sure. (Editor's note: This event is called the Electric Flight Expo, and it will be held April 25–27, 2008.) If you have a chance to go to this inaugural event, by all means be there.

If you have not experienced a large indoor RC event, attend one before this winter flying season is over. You will be amazed by how much you gain from attending one. Not only is it a lot of fun, but the amount of knowledge and helpful information exchanged is phenomenal. This is where you meet and rub elbows with the top pilots in the country. The nice thing is that most of them are very friendly and will take time to help you with any aspect of your helicopter. Even though they might fly for a different company, it is okay to ask them to help you. Their job is to help anyone, no matter what brand they fly. So do not be bashful; just ask politely for their assistance. You might be surprised by how responsive they are.

Help! I think I'm gonna give up this frustrating hobby!

You are not alone if you feel this way. I have said it myself. Sometimes you get into a "funk" where everything just seems to go wrong. When you fly, you crash. When you are building, nothing is going together right. Your parts order that was supposed to show up the Friday before the fun-fly comes the following Monday. Anyone who has been in the hobby for a while probably knows what I am describing. At these times it seems like a black cloud is hanging over you.

With little feedback from readers, I sometimes wonder if these columns are reaching anyone. I recently received a letter from somebody in Jonesburg, Missouri, so that proves at least one person is reading. He is having problems getting his helicopter going; here is what he wrote:

"No, you're not sending useless information down a black hole. Your helicopter articles are the first ones I read every time I get my Model Aviation magazine.

"My problem with helicopters is that everything I read is tailored for the advanced flyers. I bought a great little book on helicopters, but about all it did was define a lot of the words that you hear in the heli world. Actually I needed that, but as far as setting up pitch curves and throttle holds (etc.) ... I still haven't a clue.

"The guy I bought the helicopter from got me partially set up, and I was able to do some hovering, but there is a lot more to setting this up. I've got about $1,500 wrapped up in this hangar queen, with batteries going dead and fuel going bad.

"Do you think that once in a while, you could throw guys like me a bone, and give us some basic information on how to get started?"

I was glad to receive this letter because it brought some things to my attention. I have had a running theme in this column that tends to appeal to more advanced pilots. I am going to make a point of including some of the basics to help pilots who are new to the hobby.

Balancing stuff

Whether you are an expert or taking your first steps on the yellow brick road to helicopter bliss, there is one crucial thing you must do: balance your whirling, spinning, rotating components.

Three things need to be balanced on your helicopter for it to fly smoothly:

  • The main rotor head
  • The tail rotor
  • The fan or drive system

I know many people never balance anything, but their helicopters wear out much faster and they have more part failures because of excess vibration. The main rotor head is generally going to produce the most visible vibration on the helicopter if things are out of whack. Canopy vibration, tail bouncing, and skid vibes are some of the prominent effects.

Rotor-head speeds are roughly 2,000 rpm. Vibrations at that frequency are easy for the human eye to see.

Much has been written about balancing rotor heads. The system I use is the same as car-tire balancers; it is called dynamic balancing. That means the head is balanced while in rotation. That is the best way.

There are other ways to static-balance the head, but they are a waste of time for this reason: you have to take the whole head off the helicopter and put it in a balancer. After you are finished, if one main blade leads or lags you will have a shake because the dynamic balance is off. I believe that only dynamic balance is important, and I'm going to describe how I adjust it.

Promise me you will not laugh: I use a roll of black electrical tape.

Years ago everyone at the field used to laugh at me when I stuck different lengths of tape on my model's blades and spooled up to check the balance. It does work, though. Remember when you drive down the road in your car that it is smooth because of dynamic balancing. There are little bits of weight on your wheels just like the little pieces of electrical tape I use on the rotor head.

A simple method to check and correct canopy or head vibration (no disassembly required):

  1. Take off and hover, note the amount of canopy vibration.
  2. Put a 4-inch piece of electrical tape on a blade or a paddle at its center of gravity (CG) or near it.
  3. Take off again and observe whether the vibration is worse or better.
  4. Move the tape to the other blade/paddle and repeat to check which blade/paddle affects the vibration most.
  5. When you isolate the blade/paddle that reduces the vibration the most, add another 4-inch piece of tape to that same blade/paddle.
  6. If the vibration increases, reduce the amount of tape. If it decreases, you can try adding a bit more tape. Trial and error until you get it as smooth as possible.

Every one of my machines has electrical tape on it for balance. If you want it to look nice, figure out how much tape you need and substitute the same amount of weight with matching MonoKote trim tape on the underside of the blade/paddle.

A reader replied that this technique got rid of his vibrations. Note that canopy shakes can come from a variety of sources, so this technique won't always fix every case. It's a convenient, accurate first check for head imbalance. Next time we will get into tail and drivetrain balance issues.

That is all I have space for this time. I will try to include tips such as this every other month or so. Please write and let me know if this is the direction you would like to see the column heading. Thanks for reading.

MA

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Transcribed from original scans by AI. Minor OCR errors may remain.