efish

My Feedback: (5)

Hi all, I just started my first gas engine - a brillelli 25GT magneto version.

Although the first start did take about 50 flicks working alone, it all went a lot easier than I expected! Every engine is different I guess and I wanted to take my time getting to know this one (and avoid hacking my fingers off!) Second start only took about 8 flicks so I guess I must be improving! Anyhow, I now have a few questions and I was hoping for some help.

Some background - the engine was bought secondhand with a plane. The previous owner claimed that his friends put in a couple of flights on it, but looking the engine over, it seemed brand new and unrun. The plug wasn't even tightened. For fuel, I'm running 98 octane with a blended synthetic oil in a 25:1 mix (that's probably too oily, but I didn't know what to expect from this engine; will gradually decrease the oil content to 32:1 and then 40:1). Don't know anyone who flies gas at my field, so I've spent the last couple of weeks reading up from the web and from various instruction manuals.


#1 Black Exhaust Residue
I was told that all gas engines spew out a dirty black exhaust residue at least until they are broken in which will take a few gallons. Well, this one certainly made a mark on my bench top! I'm used to cleaning up slime with my glow engines, but this black stuff is new! It is slightly oily, but no where near the thick phelgmy consistency of the exhaust from a glow engine being run rich.

It this anything to worry about?

The engine still needs a lot of breaking in - its running a little rough and the rpms seemed to be wandering a bit. Couldn't use my tach since its night here, but I will tommorrow.

#2 Prop/Magnet position
I'm scared that gas engines seem to start so easily - no heater needed! Dun know much, but would it be correct for me to conclude that the magnet must spin pass the sensor for the engine to start? Well, if so, then for the 25GT, would a safe transport storage position be with the magnet directly opposite the sensor?

For starting, right now I've got the prop at the 2 o'clock position when resistance is felt. This puts the magnet about 45 degrees away from the sensor. Would this be about right? Or is there a better way to set this up? The Fuji manual recommends having the magnet about 20 degrees away from the sensor when resistance is felt. Should I even bother trying to move the flywheel to accomplish this?

#3 Do I need a kill switch?
I've had different opinions shared with me on this. In fact, I've already purchased a great planes kill switch. However, when I ran the engine today, I found that I could shut it off by closing the throttle. Will this change as the engine breaks in?

Should I install the kill switch?

#4 Breakin in the air?
I like to break in my glow engines in the air - nitro is way too expensive to keep putting tank after tank through an engine on a test stand. Would this be a reasonable proposition for the 25GT? Will run a few tank fulls on the ground, but thereafter, can I just go fly the engine (tunned slightly rich, of course)

#5 Spark Plugs
I got a few NGK 7543 - CMR7A plugs with the engine. Are these the right plugs to be running? Should I be thinking of a colder/hotter plug during the breakin/initial flights or to account for warmer weather?

Guess that's it for now. The engine seems to be running generally ok except for a slightly burbling midrange and a sluggish transition. Actually, I haven't even opened up the throttle fully but there seems to be plenty of power. Will probably put a few more tanks through it at lower rpms before trying to tune it up for flight.

Thanks all.

Zippi

My Feedback: (10)

efish,

I had the Brillelli 25cc/EI a while back on a GSP Giles 202 73". I now have the Brillelli 26cc/EI on it. After you have fired the engine up and tweaked the needles you can go fly. Gassers are not like glow engines, you do not have to break them in with a lot of fuel. I can't help you with the kill switch, everything I have is on EI. The black residue coming out of the exhaust is normal and after a while it will go away. It's hard to get of the covering and I have found that Pledge will get it off. As far as the plugs, shoot Scott at [link=http://www.scottellingson.com/]Brillelli engines[/link] and email and ask him what he put in them when he shipped the engines. When I switched to the bosch cap I had to get a different plug.

efish

My Feedback: (5)

Thanks, Zippi. Pretty reassuring about the black residue.

Guess everything is in order for a maiden next weekend. Will put a few more tanks through the engine on the ground, though this would be more to practice my starting technique than anything else.

Chevelle

My Feedback: (2)

About your item #2, magnito engines create a spark when the magnet turns past the coil. The faster it turns past, the higher the current in the coil. For transporting, there is no way that the prop could ever move fast enough to accidentally start the engine. That is not something to worry about.

That being said, I would never suggest that you transport your plane with fuel in it. No fuel, no accidental starts. Finally, I highly recommend the kill switch. Then you can be assured that the engine will not start unless you want it to. Good luck.

jbflier

efish; For the kill switch check out www.rcatsystems.com . I've used their simple kill switches and highly recommend them......[8D]

Edited to fix the link
Rcpilet

karolh

First off, welcome to the gas world of flying, and I will try to answer your questions as best I can.

The black goo that you are experiencing is due to the fact that the engine is new, however this will diminish with run time. Too much oil will produce lots of goo, and I think the a 25:1 mix is a bit much and would suggest a 32:1 mix.

For plugs always use one with the letter 'R' in the marking as this signifies that it is a resistor type plug which is necessary to help guard against radio interference from the ignition.

There is no need to mess with the engine as any prop placement between 20 to 2 or 15 past 9 on the clock face when compression is felt is a good starting point. This is a magneto type ignition which which unlike a elect type ignition needs to be spun fairly fast to generate a spark. For initial startups you need to choke the engine to get fuel into the carb and to the engine, otherwise you will have to flip numerous times before the engine will fire up.

Fitting a manual engine kill switch is a good practice and should be considered mandatory. The use of an electronic kill switch is debatable, as some do and some don't, but for me I like having the option of killing my engine from the TX.

Gas engines don't need any extensive bench running and should never be run excessively rich. Most of the engine breaking in is best done in the air. Tune the engine as best you can for max revs less 300 rpm with a good transition from low to high and a steady idle and you should be okay. Your engine is new so don't expect a low idle. As it breaks in it will run smoother, produce more power and will be able to idle at a much lower rpm.

Gas engines vibrate a lot more than glow engines so locktite all metal to metal fasteners and do periodic checks of all connections. Remember to AVOID any metal to metal throttle connections like the plague. Now go fly and enjoy.

Karol

jbflier

Here's food for thought with regards the kill switch issue......I once saw a guy loose his throttle servo (for whatever reason) flying a gasser and his batteries ran out before the ran fuel did............[&o] To me it's worth the $25.00.............[8D]

Sewerdude

My Feedback: (20)

How does the kill switch really work? Do you have to have a available channel? I've got extra ports on the reciever but all my channels are used up on my radio.

karolh

You need a dedicated channel to operate the RCATS electronic switch which is the brand I use, so maybe it's time to upgrade your Tx to one with more channels

Karol

efish

My Feedback: (5)

Thanks for the tips guys.

Will install the kill switch on the plane. On the bench top, I've take to just unplugging the spark plug as a precaution. It does sound like a sensible and pretty cheap precaution both to avoid accidental starts, and perhaps just as importantly, as a fail safe to be able to kill the engine in the air.

Karol, I'm changing out my fuel to a 32:1 ratio. Did the first few tanks on 25:1 since I didn't quite know what the last guy did to the engine. With my glow engines, I always add a little more lube to the first few tanks when dealing with "suspect" engines.

Thanks again!

karolh

Attempting to disconnect the plug cap with the engine running is an unsafe thing to do and should not be done. Simply grounding one lead on the engine case will shut it down.

It's better to have too much oil for the first few runs of a new engine rether than too little, so no harm done. Just remember a gas engine should not be run blubberingly rich like a glow motor and use an oil specifically designed for 2 stroke AIR cooled engines.

Karol