Eddie P
Posts: 678
Joined: 2/4/2003
From: Reno,
NV, USA
Status: offline
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quote:
ORIGINAL: NorfolkSouthern
On my first flight, the instructor and several other people asked me how long I charged the batteries in the plane's receiver. At first, I told them that I charged the batteries initially for 15 hours, as per the instructions. My plane was grounded for that day as a result of my answer. They told me to take it home, drain the batteries, and run the charger for 24 hours. I simply did what I was told, and did not question them. I saved the photos to the two incidents discussed here too, so I can perfectly understand WHY they were so serious about the batteries. I brought the model back to the field a few days later, and everything checked out fine during the range check. I followed their instructions, again, no questions asked. That day, I got two flights in safely, my first flights on the trainer box.
The duration of a battery's charge does not tell me everything I want to know about a battery's health, unfortunately. My model doesn't have a volt meter that can tell me what the charge level is on the batteries before flight. Although that UAV (it's a model aircraft to some, but I consider it as an unmanned aerial vehicle) is airworthy, I took it upon myself to take it out of service for that very reason. That plane is not going to fly until I get a volt meter that will tell me how good the batteries are before I even start the engine. Why am I doing this? Because the field is close to an expressway and a residential area. If a plane ever loses contact with the transmitter because of undercharged batteries and hits a car, hits a house, injures somebody, or kills somebody a few miles away, you can very well bet the authorities WILL find out who that model belongs to. Needless to say, it WILL NOT be mine if I can in any way help it. If somebody gets injured or killed, the cost of a new plane to replace the one that gets lost is the the last thing to worry about.
NorfolkSouthern
Hi NS-
The battery voltage on NiCD or NiMH, sitting idle under no load, doesn't tell you much. You have to place a load on the batteries and then look at the voltage drop to determine the condition of the cells. There are a few ways of doing this but a high quality charger like a Schulze Camelian or similar, which can condition packs and cycle them, will give you a much better indication of the pack's health.
Besides the attention to the battery condition, which is very good when taken into context, it is also very important to concentrate on the whole airplane as a series of systems: flight controls, airframe, powerplant, radio link (airborne and TX), servos, etc.. They all play an important role and their neglect can cause any number of problems.
However, in the particular case in Hungary, the model airplane and transmitter seemed to have been in perfect condition. It appears a mobile radio station hijcked the frequency that was in use to control the model airplane, and caused the resulting lock out that led to the crash. This is very much an issue of how the event was conducted and the oversight of the event coordinators.
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RE: 2 death 4 wounded in model airplane crash - 
RE: 2 death 4 wounded in model airplane crash - 
