acro50

Thanks Ed, I took up your suggestion and bought the GMS 76 instead of the 61. Same physical dimensions. My LHS suggested an OS A5 glow plug. Is this suitable for this engine? I have never used an A5 before, only A3, A8 and OS F. Any suggestions, guys?

Thanks

Ed

majortom-RCU

My Feedback: (40)

On my Tower 75, which is pretty comparable, I do well with a K&B L1, which is a hot plug. The OS A5 is a cold plug, for high nitro off-road racecar engines. I don't see how that would relate. If you want OS, I'd go with the A8, which is also rated hot.

Ed_Moorman

My Feedback: (1)

I agree. The A5 would be too cold. You can tell because when you remove the battery, the rpm will drop a good bit. The A-3 would be a better plug or the OS #8. As has been mentioned, the K&B-1L is also good as it the Thunderbolt #3. I may be wrong, but it sure looks like the Tower Power plug is an A-3 with another label.

If you look at the coil and hole in the plug body, you can tell a hot or cold plug. Colder plugs have a small hold so the metal body is closer to the element (coil). This allows the heat to more easily transfer from the coil to the body, making it colder. Hot plugs have big holes. Next time you are at your local hobby shop take a look at the different plugs.

Don't forget to give your GMS 3 or 4 tanks of slobbering rich running, then run a smoke trail in the air for a while. Ringed engines do take a longer time to break-in compared to ABC types, but they will last a long time.

RonC

GMS 76 runs very well with OS 8 plug. Good idle, good transition and excellent performance

FlyNBHappy

My Feedback: (7)

It depends on what nitro content you're running. I run 5% in my GMS with a hot plug. Any nitro content over 15% needs a colder plug.

acro50

Thanks for all of that, guys, I will return the A5 and get an A8 and try the engine. Have not started it yet. Only got it yesterday! No guesses what I will be doing over the weekend!

If there is any other info/issues/setup procedures, etc. re this engine that you are aware of, please let me know. Always willing to learn from the experts. Thanks.

Cheers

Ed

majortom-RCU

My Feedback: (40)

Well, since you ask, I will recommend you get a bottle of castor oil from your LHS and add 4-6 oz to your first gallon, which can be either all castor lube (hard to find these days) or at least a blend of castor/synthetic. Ringed engines really need some castor in their regular diet, and especially so for the first gallon. As Ed says, run the first few tankfuls definitely rich; then after maybe 20-30 minutes of running, lean it out over several flights to 8000, then 9000, then 10000 rpm. As soon as the engine sings with a steady note, and with enough thrust to pull the plane, you can put it in the air--but be sure you have your low end set for a slow enough idle to land with. You will probably notice improvements in power over the first 5-10 gallons. My ringed engines seem to get better every year. I run them out of fuel at the end of the day, and work 10 drops of oil into the bearings.

acro50

OK, I'll do that. Any suggestions for prop sizes for my 3D plane (55" span).

majortom-RCU

My Feedback: (40)

I'd break in with a 12x6, then try a 14x5 or 15x4.

Flyboy Dave

My Feedback: (21)

....Fox Miracle plug....[sm=thumbup.gif]....(trust me)

FBD.