redbird340
Posts: 41
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Joined: 2/14/2007
Last Login: 3/14/2009
From: Richmond, BC, CANADA
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Troubleshooting
Troubleshooting: .049 - .061 Engine Won't Even Pop
You own a NORVEL .049 or .061 engine, and you are having trouble getting the engine to pop or to show signs of starting. (Popping is when the engine runs for a split-second then stops).
First of all, you should read the technical article in this web site entitled, "Starting a NORVEL Engine." If you've read this article and still can't get the engine to pop, then read on.
All NORVEL engines are individually started and run at our manufacturing facility, so it is almost certain that your new NORVEL engine will pop if properly started. Technically, popping occurs when the glow plug is hot enough to induce combustion in the combustion chamber, and when there a small amount of fuel/air mixture in the combustion chamber. The result is that the fuel/air mixture explodes, the engine runs for a split second, then stops.
This would be a good sign. When the engine is popping, it means that your glow plug is hot enough, your fuel is good, and the engine is ready to run. Just open the needle valve incrementally, keep popping the engine, and, when the needle is set to the right place, the motor will keep running.
Unfortunately for you, your NORVEL engine won't even pop. There's really only three possible explanations for this. Either no fuel/air mixture is getting into the combustion chamber from your priming, the glow plug is not hot enough, or your fuel is old or bad.
For the most effective priming procedure, read the article "Starting a NORVEL Engine." If you think you're priming the engine right, you probably are.
So turn your attention to the glow plug. If your NORVEL engine came equipped with the #100138 plug, you may need a stronger battery to heat the plug. You can check which plug was shipped with your engine by looking at the exploded diagram on your instruction sheet. If you still can't tell which plug shipped with your engine, call NORVEL at (330) 425-3631 for technical assistance.
The cold glow plug #100138 is really cold, which means that it requires a lot of battery power to get hot enough to make combustion. If you are using 2 D-cell batteries, or a standard 1.5 volt hobby battery with a #100138 NORVEL glow plug, chances are your plug is not getting hot enough.
You can check this by removing the muffler and looking in the exhaust port while the power supply is attached to the glow plug. It should radiate bright orange, visible even in daylight. Don't stick your eyeball up to the exhaust port!
Hearing a sizzle doesn't mean the plug is hot enough for combustion. It really needs to be hot, and checking for the brightness of the glow, from outside the motor, is a good check.
If your plug is barely glowing, then you need either to increase the power supply to the glow plug (with a hobby power panel turned up to 3-4 amps) or to use a "hot" glow plug. Hot plugs are available from NORVEL; they're called the #110138 Freedom XL‘ plugs. Also, you can use a Cox glow head if available.
A #110138 Freedom XL‘ plug will get hot enough to make combustion with even a hobby battery or D-cells. Make sure your hobby battery or D-cells are fresh, though, because weak batteries won't work even with a hot plug.
The best solution for the long run is to use a Freedom XL‘ plug with a Du-bro Kwik-Start rechargeable NI-CD glo- ignitor. These glow plug ignitors are compact, powerful, rechargeable, and inexpensive when compared to the price of battery purchases over time.
Troubleshooting: Problems with the NORVEL #102100 Fuel Tank Mount
The NORVEL fuel tank mount was designed as a multi- use fuel tank mount for R/C and control line. As such, it should be a strong, vibration-free mount, a leak-free fuel tank, and a steady source of fuel in tight manuevers and inverted flight. The fuel tank mount should have external dimensions that allow for use of NORVEL and Cox engines on the thousands of kits already designed for Cox reed valve engines: RTF's, sailplanes, control-line planes, etc. The CG cannot be changed too much when upgrading a Cox reed valve .049 to a NORVEL .049 with fuel tank mount. The tank should hold as much fuel as possible. And, of course, the engine with tank mount should fit inside a common canopy of 1/2A airplanes.
As you can see, a lot is asked of our little fuel tank mount. For the most part, it does its job extremely well. It only holds 0.5 oz. of fuel, enough for 2-3 minutes of flight with an .061 and 3-5 minutes of flight with an .049. But it is sturdy, vibration-free, and leak- free.
The biggest problem customers have with the tank is filling it. Because there is not enough volume in the tank for a clunk system, some design compromises have to be made to provide for fuel suction during manuevers and inverted flight. Instead of using the two-pickup system employed by other manufacturers, NORVEL uses a single brass pick-up tube that sucks from the CENTER of the rear part of the tank.
Upon first glance, some customers are confused how this will work during inverted flight. Well, the air ram vent partially forces the fuel to the rear of the tank, and the rest is handled by physics. Remember the physics lesson where a bucket is swinging in a vertical loop, yet the water stays in the bucket? Well, the NORVEL tank mount uses this same principle to keep fuel in the small cup at the rear part of the tank.
As long as fuel stays in the rear of the tank (which it will unless flight is very slow), it will be picked-up from the pick-up tube.
This is great, except when filling. If you use the vent tube for filling, fuel will pour out of the tank's pick-up tube as soon as the tank is half-full. But, if you point the nose of the airplane towards the ground, you can fill the tank to the top without a problem. And that's the solution.
Some customers who use the tank mount on sailplanes find that the pick-up system will not suck all the fuel from the tank. In this case, it is best to remove the pick-up tube gently and bend it so it will pick-up from the bottom of the tank. This modification will prevent sucking during inverted flight, but this is not a concern for sailplane pilots.
Another common complaint about the fuel tank mount is the position of the fuel pick-up tube. If you find the end of the pick- up tube to be too close to the mounting bolts of the engine, just bend it up a little. If you have a hard time putting fuel tubing onto the tube, you may want to try small fuel tubing. Medium tubing is sometimes too big to fit onto the tube as designed.
We hope you find these tips on the fuel tank mount to be helpful. We also hope that you will understand why any fuel tank mount cannot serve all needs perfectly. It may surprise you to learn that we actually recommend using an external fuel tank whenever possible when building or designing a model airplane. An external tank will hold more fuel and will work more reliably in inverted flight and for filling.
Troubleshooting: .049 - .061 Engine Cutting-Out
Cutting-out can occur when the engine is running at high rpm, or at idle. Cutting-out is defined as a very abrupt stopping of running just as it was running perfectly.
The most common cause for cutting-out is over-compression. The NORVEL cylinder/piston set is quite tight from the factory, and each NORVEL engine is set with one copper gasket underneath the glow plug. By adding the two additional gaskets supplied with your engine, you will reduce the compression. This will help eliminate sudden cutting- out.
Over-compression causes pre-ignition, which will stop the piston during its upward movement in the stroke. Cutting- out can happen at high or low rpm.
If you're using 25% or 35% nitro, you may even need to add more gaskets, since higher nitro will increase compression. This is one reason why lower nitro is better for breaking in your engine.
A good rule is to start breaking-in a new engine with 15% nitro (NVX15 fuel is recommended), the #110138 Freedom XL glow plug, and all three copper gaskets #110117 supplied with each engine. One .2 mm gasket is installed in each engine, and two .1 mm gaskets are taped to the instruction sheet. Be careful when removing the gaskets from the instruction sheet so as not to bend them.
Troubleshooting: .049 - .061 Engine Overheating
How do you know if a NORVEL engine is overheating?
If you have run model engines before, you probably have some idea of how an overheated engine behaves. When started cold, the engine runs fine. Then, after a minute or two of running, the engine begins to sag in power. Leaning out of the needle valve temporarily fixes the problem, but the engine just sags again after a few more seconds. It seems the needle valve won't adjust the engine. When the engine sags so much that it dies out, touching the engine will almost certainly burn a finger. Pouring fuel over the cylinder causes rapid boiling and evaporation of the fuel.
There are several causes for engine overheating.
First, if an engine is new, and hasn't been run much, it will overheat if leaned out for extended periods of time. This is most easily avoided by running a new engine rich, following the break- in procedures mentioned in the technical article "Breaking In a NORVEL Engine."
Second, if the fuel does not have enough oil content, or does not have enough castor oil in it, a NORVEL .049-.061 engine will overheat. Fuels with all-synthetic oil will almost always cause a NORVEL engine to overheat. Some large engine fuels work fine, and some do not. Read technical article "Selecting Fuel and Propellers for your NORVEL .049-.061 Engine" for more information.
Third, if the engine has an air leak, it will overheat. Air leaks are sometimes visible as bubbles coming-out from the glow plug area at the top of the cylinder or from the rear coverplate. Other times, air leaks are located at the needle valve threads, more difficult to detect because bubbles will not form on the needle valve screw.
Air leaks will make the engine very difficult to start, and it will run poorly even when running. Using a tachometer to test the engine at maximum rpm is one good way to check engine performance. A low tachometer reading can be the first indication of a problem with an engine.
If your NORVEL engine is overheating consistently even when you run a recommended fuel after 30 minutes of break-in, then the engine almost certainly has an air leak. Locating and eliminating an air leak can be a very simple matter, or it can be very difficult. If you are not experienced with modifying and servicing model engines, we recommend that you send your NORVEL engine to us for inspection and warranty service.
There are four places where an engine can develop an air leak. The #100117 copper glow head gasket seals the top of the cylinder against the glow plug. Putting some fuel on the head of a warm engine and turning the propeller will indicate leaking if bubbles are seen rising from the seam between the glow plug and the head. Similarly, soapy water can check for leaks on the coverplate and cylinder head gasket areas. As previously mentioned, air leaks on the needle valve cannot be identified easily. Placing a piece of small silicon tubing over the needle valve, sealing the threads may eliminate a leak. Success can only be determined by subsequent running and taching of the engine. Silicon sealant can be used on the rear cover plate area to eliminate small leaks.
In any case, leaks are very rare in NORVEL engines, but it may be helpful for you to know how to eliminate them, especially if you plan to disassemble or modify your engine. (These are the two most common causes for air leaks).
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All Forums >> RC Airplanes >> "1/2 A" & "1/8 A" airplanes >> RE: Norvel Engine FAQ 
RE: Norvel Engine FAQ - 
RE: Norvel Engine FAQ - 
