That is the only choice that I have at the LHS. Which would be better for Stunt?
Tia.
Frank
Glow Plugs can also be a major cause of trouble, and poor runs. When you first crank the plane, notice if it goes rich and sags slightly when the battery is removed; if so, the plug is normally too cold. This is critical to getting a proper Stunt run.
Most plugs are designed to provide a colder range than we want in C\L aerobatic engines , and you should try to get the right range for the motor. Many days of testing and much time and expense buying almost every plug on the market has yielded these results ;Thunder Bolt R\C long, T Bolt #3 , T Bolt 4 stroke, Glo Devil RC #300 long, Enya 3 & 4, Fireball RC long, the Hobby Shack RC long, SIC RC long a few of the OS hotter plugs and some of the FOX long and Miracle plugs are best plugs for our use. In almost all instances, use a long plus, as they will be substantially hotter than the shorts, plus they are deeper in the combustion chamber and this tends to keep things hotter and keeps the plug elements cleaner.
A lot of times the plug problems show up as rich inside maneuvers and leaner outsides; this happens because gravity and centrifugal force ,forces the oil-fuel charge down on the element on insides, thus cooling the coil and pulls it away on the outside maneuvers, letting it naturally go leaner. I have seen this problem instantly cured by simply changing plugs. Please do not be afraid to put in a new glo plug , or try different types of plugs .
All of this assumes you have your tank height perfect (you did adjust your tank height, didn’t you), you’re right side up and inverted lap times are the same. This is important; don’t skip this step. If your using a profile sometimes you will need to have the tank center higher than the engine center. The 3 \16 to 3 \8 range will do for most fox 35s . Others will run on center line ,or just off of it. Another case of run problems are tanks or fuel delivery systems, which includes the tank, fuel tubing ,fuel filter, and anything else connected to the fuel system. When these problems arise in most cases, the engine changes speeds in flight, either faster or slower , and is generally inconsistent in the needle setting. This is almost always blamed as an “engine problem” when in fact it almost always turns out to be a tank problem, or fuel delivery system problem. I find most every time I see this , it is one component of the fuel system that is at fault. Either a hole in the fuel tubing, junk in the filter, a hole in the tank, a tank with an internal crack in the pick up or feed line . The next most common problem of this is water in the fuel. Water will give a very inconsistent needle setting, and will change at random back and forth from lean to rich. There are a few other things that cause problems with fuel delivery, muffler or pipe pressure will, most times magnify any little leak or problem you have and make things much worse than they were. A few other causes are an engine with a leaking backplate gasket, or an improperly cooled engine. A basic rule of thumb is to have a good intake area, with double the size of the exhaust area. Make sure you model (if fully cowled) has the air blowing all the way across and past the engine before the air flow exits the cowling. If your plane goes lean in maneuvers and comes back to a four-cycle slowly, it can be running too hot, you most likely need more oil, or less back pressure from the muffler. I have seen a lot of fuel with water in it (methanol attracts water) and this will cause erratic runs and needle settings. Always use fresh fuel and don’t be afraid to try another fuel if you think this is the problem.
Topic: Which plug, Fox RC or Enya No. 3 (Read 1185 times)
