Articles

The Runway

11/9/2005 by Gary Katzer

Copyright:© 2005 Horizon Hobby, Inc.

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New Entry Get the Right Support Equipment

When you start looking at planes that don’t include all the equipment in the box with the plane, you’re going to need to pick up some additional items to get your plane off the ground. One thing that has struck me about foamie planes is how few tools you’ll actually need to assemble your plane. Instead, you’re going to need things such as CA, strapping tape, and piano wire to build up your plane.

Beyond basic assembly items, you’re also going to need the proper gear to get off the ground. One of the most important items you will purchase is your battery charger. Your particular battery needs will help determine which charger is ideal for you. If you don’t plan on moving into Li-Po batteries any time soon, you can go with a Ni-MH/Ni-Cd–only charger. If you don’t plan on using anything but Li-Po batteries, then going with a Li-Po–only charger would make sense. However, if you plan on flying planes that utilize both Li-Po and Ni-MH/Ni-Cd batteries, there are chargers that will do each of these battery types. In addition to the battery type that it can charge, you should also check to see whether a particular charger can plug into a standard AC outlet or requires a DC power supply. A DC-only charger is generally smaller and less expensive than an AC charger, however, when you add in the cost and size of a power supply, it can many times be a wash. I personally prefer DC-only chargers, but that’s only because I also have a power supply with a high amperage output. A lot of this decision boils down to personal preference.

New Entry Back to the Bench

With racing 1/8-scale buggies and truggies, flying my HobbyZone® Firebird Commander® 2 and ParkZone® J-3 Cub, my E-flite® Blade CX has been somewhat neglected lately. One of the reasons is that I recently broke the head rotor on a hard crash and was a little nervous to swap it out.  Since I haven’t taken one of these heli’s apart before, I didn’t know what I would need to loosen up to get the old shaft out and get the new one in. I’m here to tell you this was much easier than I initially thought it would be.

I also bent my fly bar in the same flight that broke the head off of the main rotor shaft meaning I didn’t need to worry about popping off the ball link that adjusts the rotor pitch. I began my disassembly by removing the body work and landing gear. This isn’t necessarily a must-do, but it does make things much easier. From here, I loosened both set screws that held the rotor shaft in place and the damaged rotor slid right out. As the rotor slid out tough, so did the bearing that supported the top of the shaft. I proceeded to simply pop the bearing back into place, making sure it was square and not mounted off to one side or another. Next up was to slide the new main shaft into place and retighten the set screws. When you’re doing this, make sure you’re tightening the set screws down on the part of the shaft that has two flat spots. An easy way to tell where these are is to look at the head. The two posts line up with where the flat spots are. The last step is to install the fly bar and pop the ball link on. From here, just tighten everything down, put the body back on, and you’re ready to fly.

New Entry It worked fine last winter…

I admit that I enjoy surfing the web and checking out the various bulletin boards and forums to see what people are talking about. One such thread I saw on a board was entitled “My electric plane doesn’t fly as long as it used to.” Upon diving into the thread further, I discovered that it was created by someone who had just entered into the hobby last June and had recently unpacked his plane after a long winter’s storage. Once he had everything unpacked and a battery charged, he ran into several snags. First of all, he claimed that his motor was very loud and operated with a screeching sound. Secondly, he was frustrated that he wasn’t able to fly as long as he had last summer and fall. The thread concluded with the person asking the question of whether the plane is shot and he needs to buy a new one or if there’s still hope. Thankfully, there’s hope.

 

The electric motors used in park flyers like HobbyZone and ParkZone planes utilize oilite bushings to support the motor’s armature. While they can go unnoticed for some time without any major issues, when not oiled frequently the armature can cause excessive drag on the bushings and wear them out. You should use some high-quality bushing lube on both ends of the motor’s shaft from time to time. I’ve used Fantom Racing’s Bushing Oil (FAN54303) for quite some time on my motors for my race cars, and it works very well in this application too.

 

As far as the poor flight time, there’s hope there as well. While Ni-MH batteries are less prone to developing a memory than their Ni-Cd counterparts, it does still happen. The best way to eliminate this is to occasionally charge and completely discharge your battery pack (also known as cycling a pack). What this does essentially is to “retrain” your battery pack, so that it takes a full charge and improves the internal resistance. After several cycles, you should notice your performance and flight time returning to normal. While this can improve the performance in some instances, there are situations where the battery pack cannot be resurrected and you will have to replace it. That should only occur after several years of use, however.

New Entry Repairs, Repairs, Repairs

I must say that I am absolutely thrilled with the performance I have had on my Blade CX thus far. I have already flown about a dozen battery packs through my personal Blade CX and I am amazed by its performance and durability. While it spooks the living daylights out of my yellow lab, Max, flying around my home has been an absolute blast. That is, until I went ahead and got a little over-confident, flying too close to my table. Here’s what happened.

It seems like every stupid thing someone does starts with “Hey, watch this!” I admit that I did utter those words and, looking back on it, I now know I was spelling my own doom. I decided to see if I could reproduce a maneuver I saw in the instructional VCD where one of the pilots flew under a table, then backed up over the top of it. I felt like I had flown the Blade CX enough to be comfortable with attempting this, and so I set up my kitchen table to try. Now, I did think enough ahead to install the leaf in the table to give myself more room than what it had initially between the legs. Everything seemed to be going well; the approach was nice and straight and the Blade CX seemed to be tracking perfectly. And then it happened. My daughter asked me a question, and I looked away from the Blade CX for just a moment to see what she needed. As I was looking away, I heard the blades as they came in contact with the legs of my kitchen table. The next thing I knew, I had two broken blades and two split blades. That’ll teach me to keep an eye on what I’m doing. But at least the flybar and the head survived my stupidity.

New Entry Maintaining Your Battery Packs

Along with your motor, your battery packs have a huge impact on how long your plane will fly and how well it will climb. Over time, however, battery packs can lose capacity and the average voltage output can be impacted as well. I’m not going to bore you with the details of what chemically happens inside a cell that makes this happen, but I will tell you there is a proper way to maintain and store your batteries.

While NiMH Batteries (Nickel Metal Hydride) are considered to be “memory free,” you will still want to discharge them completely and balance the pack out. No two cells ever charge and discharge exactly the same. Some cells come to a full charge before others, and this means that some cells can be overcharged and potentially damaged. To make sure that your batteries all charge properly, you will want to occasionally discharge your pack completely. There are a few different ways you can do this. If you have a HobbyZone plane, there is a voltage cutoff designed into the speed controller, and you can use this safety feature to maintain your batteries. The easiest way would be to hold your plane by the nose while it is sitting on your workbench and hold the throttle open until the motor comes to a stop. Once the motor stops, don’t reset the throttle and drain the battery more. You could also retrofit a car bulb discharger, like the Buds bulb discharger (BRP6928) with a HobbyZone battery connector (HBZ1081), but there’s one key to remember. Unlike the speed controller, there isn’t a voltage cutoff built into this discharger. Once the bulb begins to dim, remove it from the pack immediately to prevent over discharging and protect your pack from potential cell reversal. Now that your packs are properly discharged and maintained, let’s get back in the air.

New Entry Motor Tech

 

Batteries and motors can be two of the most confusing aspects of the RC hobby. When I first started in this hobby, I didn’t know anything about either of these two items besides the fact that you need to charge the batteries before you run and the motor makes the car go. This simplistic view got me by for a short time, but after awhile I noticed that my motors were getting gradually slower and I was getting less and less runtime per charge with my batteries. I eventually sat down and talked to a more experienced racer who clued me in on a lot of things I never knew anything about. Not surprisingly, many of these tips and tricks carry over to the airplane world.

 

All HobbyZone planes use a sealed-endbell motor, often referred to as a Johnson, Mabuchi, or Silver Can motor. These types of motors are very basic in their construction, which can make maintenance a bit of a bear. You cannot remove the brushes from the motor to properly clean the commutator or brush face on this style of motor, but with a little effort it is still possible to maintain and clean your motor. If you look at the fuselage on the Firebird or Aerobird planes, the area around the motor is vented to allow heat to escape. This also provides a way for you to spray your motor out with Dynamite Magnum Force 2 (DYN5500) motor cleaner. To do this, remove the wing and rubber bands from the fuselage, as some solvents could potentially attack the foam wing. Hold the fuselage upside down with the tail angled towards the ground, slip the nozzle into the opening on the side of the motor and spray the motor out lightly. You’ll want to occasionally spin the prop by hand to free any dirt or crud that may get trapped between the brush face and the commutator. Once everything has dried, oil the motor bushings with a quality lube, such as Team Orion Free Revs Pro (ORI41704) or Trinity Bushing Oil (TRI4026) to extend the life of the bushings and help everything run smoother and with less friction. Now that your motor is nice and clean, it’s time to take care of your batteries. 

New Entry Into the Great Wide Open

I loaded both of my newly repaired planes into my truck and headed to where I’ve been flying more and more lately, a former military base near my apartment. The base has a large concrete section so that I can land and take off normally instead of hand-launching my planes, but there’s still enough grassy spots that if I need to set down hard or in a hurry, I can without damaging the plane too badly. Plus, the closest tree is 300 yards away! My wings are safe!!!

I was more worried about trying out the Firebird Scout since the repair work was more extensive, so I flew the Firebird Commander first. Once the Firebird Commander was airborne, it didn’t turn as sharply to the right as it did to the left. In fact, I had to give it full stick right to make it do anything. I landed it safely and made some adjustments to the control lines while it was on the ground. After a few adjustments, I was back in the air, and this time the Firebird Commander was more responsive.

To say I was concerned about flying the Firebird Scout would be an understatement. With so much structural damage to such a crucial part of the aircraft, I was afraid that the tail boom might flex too much. I was pleasantly surprised—the Firebird Scout flew great! With my two new repaired planes having survived their first post-repair flights, I went home for the night. But they will now have to compete for my attention soon, as I have just picked up a new HobbyZone Firebird Commander 2. I’ll give you a full first flight report next time.

New Entry Basic Repairs

 

After flying my Firebird Commander for as long as I have, it’s taken its fair share of abuse and rough landings. Along with the trailing edges of the main wing, the tail and prop have been in need of replacement. And, at our flying lunch the other day, the Firebird Scout nosed into the ground pretty hard and damaged the tail boom. I sat down and took an inventory of what exactly needed to be replaced. When everything was tallied up, I picked up a replacement white wing (HBZ2521), white tail (HBZ2531), prop (HBZ2004), and a new set of rubber bands (HBZ2011). For the Scout, I found that there was a simple fix for the broken tail boom: a 1.5” Tailboom Repair Kit (HBZ1047).

I sat down at my workbench with the Firebird Commander first and began to remove the old wing and prop, but paused when I got to the tail. I had to be very careful not to cross the control lines on the tail. To help me avoid mixing up which line went to which control surface, I marked one of the control lines along with the mounting bracket that it went to. I also had to be careful to make sure I ran the control lines through the correct hole in the bracket.

After about thirty minutes, I turned my attention to the Firebird Scout. The tailboom repair kit was actually designed for planes such as the Firebird Commander or the Aerobird Challenger, so the inside diameter of the tailboom repair kit was significantly larger than the outside diameter of the Scout’s boom. I simply CA-ed the two halves of the broken boom together and used several layers of heat-shrink tubing over the break. Once this was done, I glued the repair kit in place. But now how well will the newly repaired planes fly?